CA1324423C - Apparatus and method of detecting abnormal load of pressurizing apparatus - Google Patents
Apparatus and method of detecting abnormal load of pressurizing apparatusInfo
- Publication number
- CA1324423C CA1324423C CA000610074A CA610074A CA1324423C CA 1324423 C CA1324423 C CA 1324423C CA 000610074 A CA000610074 A CA 000610074A CA 610074 A CA610074 A CA 610074A CA 1324423 C CA1324423 C CA 1324423C
- Authority
- CA
- Canada
- Prior art keywords
- sampling
- pressurizing
- pulse
- detecting
- linear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/16—Rotary-absorption dynamometers, e.g. of brake type
- G01L3/22—Rotary-absorption dynamometers, e.g. of brake type electrically or magnetically actuated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/0094—Press load monitoring means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/28—Arrangements for preventing distortion of, or damage to, presses or parts thereof
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus and a method for detecting an abnormal load for a pressurizing apparatus is disclosed, in which a load change of the work is detected by use of an effective power detector or a mechanical strain detector, and values obtained by sampling at a plurality of points of pressurizing time are compared with a normal value already stored. The result of comparison is used to detect an abnormal load condition.
An apparatus and a method for detecting an abnormal load for a pressurizing apparatus is disclosed, in which a load change of the work is detected by use of an effective power detector or a mechanical strain detector, and values obtained by sampling at a plurality of points of pressurizing time are compared with a normal value already stored. The result of comparison is used to detect an abnormal load condition.
Description
1~24423 1 sAcKGROUND OF TH~ INVENTION
The present invention relates to a pressuriz-ing apparatus comprising a power source including a motor and a flywheel and a slide ram adapted for linear motion through a flywheel crankshaft to pressurize a material, or more in particular to an appara~us and a method of immediately detecting an abnormal condition and `
promptly finding a fault such as the breakage, cracking or wear or displacement by work grip failure of a punch or die of a pressure unit which may develop during the pressurizing work by tbe former ; References on àn abnormal load detection apparatus relating to the present invention include JP-B-59-229Q2 (U) f~led~on November 17, 1981 and .
JP-B-57-13~1 filed on January lq, 1980 by Sakamura Xikai ; Sei-a~usho Ltd , a tèchnical report ent1tled "Energy Sen~or Dev~loped for ~xtra ~arge Size FormerH for ntroducing nèw product- of~ Sakamura Xikai Seisakusho td~.i, and`product specifications nProcessa 3040-20 ~Processa Model ~0~0~ and ~Processa~Model~4010 Compactn `of~-Bran~amp system Peozebautomation~GmbH
Th abnormal~lQad d`etection apparatuses dl-closed in these~r~ferences are operated in such a ~ `
m~nner that a load ce}l embeddèd in`the rear part of a 25~ punch or a die records a maximum or average value of ` "
.
, ` ~32~23 1 load change for each pressurizing stroke or a sync signal is used to record an average value of load change within a predetermined specific partial area in a stroke, and the resulting value thus obtained is com-pared with a normal value for pressurizing the workwithin a tolerance thereby to detect an abnoramal condition or fault.
In these conventional apparatuses, a normal value is no~ compared with each of load changes sampled continuously in the process of work deformation at or in the vicinity of a pressurizing point of a moving pressure unit, and therefore it is impossible to detect with high accuracy an abnormal load which may occur instantaneously at a given time point while the work is under pressure.
Another disadvantage of these conventional apparatuses is that in view of the fact that the~full load is imposed on a load cell providing a sensor, it is practically impossible to use a small-capacity high-sensitivity load call capable of detecting a very smallchange under an abnormai load and that the use of a singl- data of average or maximum load for each stroke ;~
of the presQurizing work to detect a fault fails to ~ ~ , . .. .
attain an abnormal load detection with high resolution.
~: .
25~ S~#MAAY OF THE INUENTION
Accordingly, it is an ob~ect of the present ` `
` invention to provide an abnormal load detection ;
, .
: . . .
The present invention relates to a pressuriz-ing apparatus comprising a power source including a motor and a flywheel and a slide ram adapted for linear motion through a flywheel crankshaft to pressurize a material, or more in particular to an appara~us and a method of immediately detecting an abnormal condition and `
promptly finding a fault such as the breakage, cracking or wear or displacement by work grip failure of a punch or die of a pressure unit which may develop during the pressurizing work by tbe former ; References on àn abnormal load detection apparatus relating to the present invention include JP-B-59-229Q2 (U) f~led~on November 17, 1981 and .
JP-B-57-13~1 filed on January lq, 1980 by Sakamura Xikai ; Sei-a~usho Ltd , a tèchnical report ent1tled "Energy Sen~or Dev~loped for ~xtra ~arge Size FormerH for ntroducing nèw product- of~ Sakamura Xikai Seisakusho td~.i, and`product specifications nProcessa 3040-20 ~Processa Model ~0~0~ and ~Processa~Model~4010 Compactn `of~-Bran~amp system Peozebautomation~GmbH
Th abnormal~lQad d`etection apparatuses dl-closed in these~r~ferences are operated in such a ~ `
m~nner that a load ce}l embeddèd in`the rear part of a 25~ punch or a die records a maximum or average value of ` "
.
, ` ~32~23 1 load change for each pressurizing stroke or a sync signal is used to record an average value of load change within a predetermined specific partial area in a stroke, and the resulting value thus obtained is com-pared with a normal value for pressurizing the workwithin a tolerance thereby to detect an abnoramal condition or fault.
In these conventional apparatuses, a normal value is no~ compared with each of load changes sampled continuously in the process of work deformation at or in the vicinity of a pressurizing point of a moving pressure unit, and therefore it is impossible to detect with high accuracy an abnormal load which may occur instantaneously at a given time point while the work is under pressure.
Another disadvantage of these conventional apparatuses is that in view of the fact that the~full load is imposed on a load cell providing a sensor, it is practically impossible to use a small-capacity high-sensitivity load call capable of detecting a very smallchange under an abnormai load and that the use of a singl- data of average or maximum load for each stroke ;~
of the presQurizing work to detect a fault fails to ~ ~ , . .. .
attain an abnormal load detection with high resolution.
~: .
25~ S~#MAAY OF THE INUENTION
Accordingly, it is an ob~ect of the present ` `
` invention to provide an abnormal load detection ;
, .
: . . .
", ' : :.: ' `
1~24~23 1 apparatus in which a load change in the process of work deformation is determined by detecting the power consumption o~ a motor making up a power source, a mechanical strain of the former or a shock force of the pressurizing process by a sensor, and a signal thus obtained is converted into an electrical signal. The -power consumption is detected by detecting the effective power or the power factor indicating the ratio of effec-tive factor in the power consumption~ The elec~rical signal thus detected is continuously sampled and stored.
The stored value is compared with a normal value sampled previously~ I~ the dif$erence between the two values thus compared exceeds a tolerance, the pressurizing work is stopped. In detecting a load change from the power consumption of a motor, the power consumption is converted from analog to digital signals or from analog si~gnal to $requency, and pulses thus generated are counted by a counter. This count is based on the data representing the amount of shift of a slide ram in actual pressurizing work. The data representinq the shift of the slide ram is obtained as a pulse from an oscillator which derives a starting pulse from a trigger -~
pulse generated at a predetermined position of the slide r~ or a flywheel. Such a pulse may alternatively be ~"
obtained from a linear pulse encoder mounted on a slide ram or a rotary pulse encoder mounted on a crankshaft for converting the rotational energy of a motor into the linear motion o$ the slide ram. This pulse is used as a - 3 - `
' :`, 2~423 1 reference pul~e for determining the timing of sampling.
The V-F (voltage-frequency) of A/D conversion, counting of pulses, comparison and generation of a signal upon detection of a fault, are all effec~ed by a controller includinq a CPU, a RAM, a ROM, an I/O interface, or other processing devices having the required functions.
The object of the present invention for de~ecting a load change from the mechanical strain of the former is attained by sampling an output of a strain gauqe mounted on the former body.
Accor~ing to another method of detecting a load change from a mechanical strain, a pulse encoder is mounted both on a flywheel crankshaft of a power source in rotary ~otion and on a slide ram for converting the 15 rotational kinetic energy into a linear kinetic energy `~
which is used for actual pressurizing work. A pulse `
signal from a rotary pulse encoder mounted on ~he ,~
flywh el cran~shaft for~detecting an angular displace-ment of the crankshaft and a pulse signal from a linear pulse encoder for detecting the displacement of the linear motion of the slide ram are counted, processed, comparea and sub~ected to such procèss as normal-~bnormal decision, so that the difference in the number ; ~ of pulses produced under an abnormal load is used to 2S ~d~tect a oase of fault or abnormal condition, thus ` ~ producing a ~ault signal for suspendlng the pressurizing -work. The controller has built therein a CPU, a RAM as data memory, a ROM a~ program storage memory, a counter, ~ : : .. .
. : .
1~24423 1 and other processing devices having the required functions.
The object of the present invention for detecting a load change from an impact force is attained by sampling an output from a load cell embedded in the punch or die side.
According to an apparatus and a method of the present invention, a detected load change is sampled at a plurality of points for detecting an abnormal load, and therefore a very small abnoraml load condition including the breakage, cracking or wear of a die or displacement due to work grip failure which may develop during the pressurizing work and have an adverse ef~ect on the work processing is easily and accurately detected.
According to a method of the present invention utili2ing a mechanical strain, the displacement due ~o ;
meohanical strain which may develop between the ~lywheel crankshaft and the slide ram of the machine during the pres-uri~ing work is used as a signal representing a load condition, and the displacement due to strain is detected ~s a phase difference between pulæes genera~ed by two pulse encoders or more accurately as a difference in the number of pulses generated therebetween. It is thus possible to detect even a qlight change in load s~gnal with high sensitivity as a large amount of dis-placement, thereby assuring detection of high resolution of an abnormal load.
_ 5 _ :' ~ .
- . . .
`` 1324423 The invention may be suDmarized according to a firæt broad aspect as an abnormal load detection apparatus for a pressurizing apparatus, co~prlsing, power generatlon ~eanæ adapted for rotational ~otlon and including a motor; converter ~eans for convertlng the rotative kinetic energy into linear klnetlc energy;
pressurizlng ~eans for applying the llnear kinetic energy to the work; ~eans for detecting a cbange in the load l~posed on the work and converting it into an electrical signal; means for sampling ~ `
sald electrlcal signal at selected one of a plurality of ` `
pressurlzing positions and a plurallty of pressurizlng tlme points; ~ean~ for storlng a nor~al value of the electrical signal corresponding to sald sarpllng points; means for coDparlng a value obtalned by sald sarpling ~lth the nor~al value stored; and means ~` `
for deciding on an abnor~al load oondltion ~hen the result of sald conpari~on exceed~ a predeter~ined ~alue~
Accord1ng to a ~econd broad a~pect of the inventlon, there i~ provlded an abnor~al load detection apparatus for a pre~urizing ~pparatus, co~pri~ing po~er generation ~eans adapted `-for rotational ~otlon; con~er~lon reans for convertlng the -rotatlonal ~ln~tic energy into the linear kinetlc energy;
prQ~urlzlng nean~ adapted for linear ~otlon by the linear klnetlc energy; ~eans for detecting the di~placerent due to a ~echanlcal ~ -~train bet~een ~ald pre~urlzlng uean~ and ~aid po~er generation , n~an~ a~ a signal representing a load conditlon under -`
. . . .
pre~urlzatlon, ~aid ~ean~ for detectlng lncludlng means for detectlng the anount of rotational dl~place~ent of a rotary shaft ... . .
ln rotational aotlon and ~aan~ for detectlng the a~ount of llnear .
5a , . ..
132442~
displacement of said pressurizing ~eans; means for sampling and storing the amount of rotational displacement and the a~ount o$
linear displace~ent at predeterD~ned regular tlDe intervals in a pressurizin~ process; means for co~paring the amount of rotatlonal displace~ent and the a~ount of linear displace~ent ~tored as above wlth the amount of rotational displacement and the amount of linear displaceDent sampled anew in a new pressurizing process and neans for producing a signal notifying a fault when the amount of rotational displace~ent and the a~ount of llnoar displace~ent sa~pled anew exceed t~e a~ount of rotational dlsplace~ent and the aJount of llnear displace~ent stored respectively by a `
predeternined tolerance Accordlng to a third broad aspect of the invention t~ere i8 provided a ~et~od of abnoraal load detection co~prlslng the step of detecting a load change of the ~ork and converting the detectlon lnto an electrical signal; the step of ~anpllng the eleotrical signal converted at ~elected one of a plurallty of pressur~zlng positlons and a plurality of points of pre~surlzlng tl~e~ t~e step of co~paring the sanple value uith a noraal value of the electrlcal slgnal correspondlng to the sa~pling polnt) and t~e step of decldlng on an abnornal load conditlon when the result of conparlson exceeds a predeter~ined toleran¢e Accordlng to a fourth broad aspect of the present lnventlon there ls provld~d a nethod of abnor~al load detectlon `~
for a pressurlzlng apparatus covprl~lng power generat~on ~eans adapted for rotational ~otlon nean~ for convertlng the rotational klnetlc energy lnto the linear kinetic energy and pre~surlzlng . ~ ~ . .
C 5b ~ ,' 1324~23 means adapted for linear motion by the linear kinetic energy, said method comprising the steps of counting the number of pulses generated by a pulse encoder for detecting the aDount of rotational displacement of a rotary shaft in rotatlonal Dotion, counting the nuDber of pulses generated by a pulse encoder for detecting the amount of linear displacement of the pressurizing means~ and detecting an abnoraal load condition from the difference between the count values generated fro~ said two pulse encoders. : `
. `' '.
. . .
.,'','.' . .
,.: ,' ...:
C``. ` `'` :~
5c -. .
''~'~;`'',''.' 132~423 1 BRIEF DESCRIPl~ION OF THE DRAWINGS
Fig. 1 is a diagram showing an example of configuration utilizing the effective power according to an embodiment of the presen~ invention.
Fig. 2 is a diagram for explaining the opera-tion of the embodiment shown in Fig. 1.
Fig. 3 and Fig. 4 are flowcharts of programs for executing the operation of the embodiment shown in Fig~ 2.
Fig. 5 is a diagram showing another embodimen~
of the present inven~ion u~ilizing the effective power.
Fig. 6 is a diagram for explaining the opera-tion of the embodimen~ shown in Fig. 5.
Fig. 7 iS a diagram showing still another embodiment of the invention utilizing the effective power.
Fig. 8 is a diagram showing still another embodiment of the invention utilizing the mechanical strain.
Fig. 9 is a sensor output diagram according to ~n embodiment of the present invention.
Fig. 10 is a diagram showing specific steps of the pressurizing work.
Fig. 11 is~a diagram showing an output of a :
~ ~25 ensor produced at each processing step shown in Fig.
~ 10.
Fig. 12 is a diagram showing still another embodiment of the invention utilizing the mechanical .:, 132442~
1 strain.
Fig. 13 is a diagram for explaining the operation of the embodiment shown in Fig. 12.
Fig. 14 and Fig. 15 are flowcharts based on the operation explained in Fig. 13.
Fig. 16 and Fig. 17 are flowcharts showing ~-another embodiment of means for abnormal load decision.
Fig. 18 is a diagram for explaining the opera-tion of still another embodiment having the configura-10 tion shown in Fig. 12. ~ ;
Fig. 19 and Fiq. 20 are flowcharts based on `-the operation explained in Fiq. 18.
Fig. 21 and Fig. 22 are flowcharts showing another embodiment for abnormal load decision. `
15 DESCRIPTION OF THE PR~FERRED EMBODIMENTS `.``.
Fig. 1 shows an example of configuration of `
th- present invention in which a load change is detected ``
fro~ the power consumption of a motor and a referen~e p~lse is obtained from an oæcillator in a controller 9. .`
Num~ral 1 designates a former body. The rotational energy of a motor 15 is tranæmitted through a pulley 14 and`a shaft 12 to a flywheel 10 and stored therein. A
- : ~
flywh el cran~shaft 2 is connected to a slide ram 5 by a connecting rod 4, so that the turning effort 12 of the ~ .
25 "flywhe-l crankshaft 2 is converted into a linear motion `~
13 of the slide ram 5. ~ punch 7 is mounted at the -for~Ard end of the sllde ram 5, a die 8 is arranged on a , .
7 ~ ' . ~
132~423 1 frame 11 of a former 1 at a position in opposed relations with the punch 7. A proximity switch element 17 for generating a trigger pulse providing a start pulse for the oscillator in the controller 9 and a sensor 18 therefor are mounted on the flywheel 10. The motor 15 is connected with a power consumption detection means 16 for detecting the effective power EI cos~ of the power consumption.
Fig. 2 shows the operation within the con-troller 9. This operation is entirely controlled by a program under the control of a CPU. A power consumption waveform for the pressurizing work assumes a smooth form as shown in Fig. ~(a) as an actual load change is somewhat integrated by the energy storage-discharge `
15 function of the flywheel 10. The power consumption `
waveform (a) is detected as a load change waveform by a power consumption detection means 16. The output thus produced is subjected to a V-F conversion, thereby producing a detection pulse output higher in frequency for a high power consumption as shown in (b). When the flywheel 10 rotates with the proximity switch element 17 passing through the ~ensor 18, the oscillator pulse of (c) is generated. This start pulse couses the oscil-lator w~thin the controller 9 to be enèrgized thereby to generate a pulse shown in ~d) at reqular intervals of .
time. This pulse provides a re~erence used as a sampl-ing pulse for counting detection pulses. A reference pulse may alternatively be generated at predetermined ` ' ' - 8 - ~
1~2~423 l intervals of time by counting the time in accordance with a program instead of by using an oscillator. The count value of detection pulses is sampled and stored each time of generation of a reference pulse. The detection pulse count value may be reset each time of generation of a reference pulse or an integrated value~
An example of reset~ing a counter each time a reference pulse is generated is shown in ~e). The number of samplings is determined appropriately in advance by a program taking into consideration the time at which the change area of power consumption charged in the flywheel is capable of being caught, or a detection point.
A reference value is obtained by conducting the normal pressuri~ing work several times and averaging ~ -the count value of the detection pulses sampled for each reference pulse. The several pressurizing work for ; `
dotermining a reference value may be either initial several ones or given s-veral ones of all the work that ;~ have ~lready been conducted. As another alternative, an .
appropriate value may be written as a part of the program. A reference value is stored as Al, A2 and so on of ~f). In actual pressurizing process, each time a reference pulse is genèrated, tho count value of detec-tion pulses sampled is compared with a reference value.
If an abnormal load condition occurs as shown by dashed line in the waveform (a~, the nùmber of pulses at or around the time point of abnormal load occurrence increases as shown in (g). At this time, the detection ..;':`'':
, .: .
_ 9 _ ~ 324423 1 pulse count value A'5 shown in (h) is compared with a reference value A5, and if the difference therebetween exceeds a tolerance (x), a fault signal (i) is generated thereby to stop the pressurizing work.
Program flowcharts are shown in Figs . 3 and 4.
The flowchart of Fig. 3 is for determining a reference value. step 31 monitors the generation of a reference pulse, and upon generation of a reference pulse, step 32 stores the count value of detection pulses. Then, the integrated value of reference pulses is stored àt step 33. Instead of storing an integrated value of reference pulses, the sampling number may be identified by the address of a memory for storing the count value of detection pulses each time of sampling thereof. Sampl-ing is not necessarily effected each time of generationof a reference pulse but by a selected reference pulse.
In order to determine an average value for a number n of normal pressurizing work repeated, step 34 monitors whether a number n of pressurizing work has been com-pleted. At the end of a number n of pressurizing work,step 35 determines an average value of counts of the detection pulses for the same integrated value N of reference pulses associated with the number n of normal operations, and step 36 qamples the average value and stores it as a reference value for the N-th dètection pulse count.
A flowchart of a program for decision on abnormal load is shown in Fig. 4. Steps 31 and 32 :
~, ' .
132~23 1 sample a detection pulse count value from the N-th reference pulse. Step 41 reads the reference value for the N-th sampling from the memory, and step 42 deter-mines the difference between the sampled value ana the reference value, wAile at the same time checking to see whether the result of comparison exceeds the tolerance X
assuring that the work piece is capable of being processed within the tolerance. If the difference exceeds the tolerance x, step 43 decides that a fault has occurred and produces a $ault signal. If the difference does not exceed the tolerance x, step 44 starts the next pressurizing ~-ork.
- In this embodiment, proximity switches 17 and 18 may be mounted on the slide ram 5 and the frame 11 15 respectively. ` "`
(Embodiment 2) Power consumption may be detected as an analog : `
value and sub~ ected to analog-to-digital instead of voltage-to-frequency conversion and may be stored in .
digital form. A circuit configuration for such a method is s~own in Fig. 5, and the operation thereof in Fig. 6. `~
A start pulse shown in ~b) is generated by proximity -sensors 17, 18 or a program, and with this time point as a reference, an output signal of a power consumption 25 detection sensor representing a load change is sampled. -The sampling value is subjected to A/D conversion and stored in memory. Reference values are stored as Bl, ~
' "' "` ' - 11 - . ~.
'.'''. '~
132~ 23 1 B2, SO on as shown in (d). The reference value is determined in the same manner as in Embodiment 1. Each time of pressurizing work, the sampled analog signal is subjected to A/D conversion, and is stored as Bl', B2', so on as shown in (e). If an abnormal load occurs as shown by the dashed line in Fig. 6, the A/D conversion value Bn' undergoes a considerable change, and if the difference thereof with the reference value Bn exceeds a tolerance X, a fault signal shown in (f) is generated thereby to stop the pressurizing operation.
A flowchart for the aforementioned operation is obtained by replacing the count value of detection pulses with an A/D conversion value in Figs. 3 and 4~
In the prccess of comparison, each A/D con-version value may be compared with each corresponding reference value, or the sum o~ a predetermined continuous number of A/D conversion values may be compared with a corresponding normal value. As another alternative, an integr~ted value of A/D conversion `` `
values may be compared with a corresponding normal value for each predetermined number of samplings. ` `
The above-mentioned methods o~ comparison o~ ~-A4D converQion value are applicable also to all other embodiments.
The proximity switches 17, 18 may be mounted on the slide ram side.
. . ,' ."', .. ..
132~23 1 (Embodiment 3) Fig. 7 shows ano~her embodiment in which a load change is detected from the power consumption of a motor and a reference pulse is produced from a rotary pulse encoder 3 mounted on a flywheel crankshaft 2. If a rotary pulse encoder having a start pulse built therein is used in this embodiment, the oscillator in `.
the controller and the proximity switch for generating the start pulse of the oscillator are eliminated. The operation of this embodiment is identical to that of Fig~ 2 lacking the oscillator start pulse (c). The flowchart of the program of this embodiment is the same `
as Figs. 3 and 4.
The same object o~ operation is also achieved by a linear pulse encoder 6 having a start pulse built therein mounted on the slide ram side instead of a rotary pulse encoder. ~
', ' (~mbodiment 4 An embodiment in which a load change is detected from mechanical strain by a sensor which converts the load change into an electrical siqnal is s~own in ~ig. 8. A load cell or a piezoelectric device is generally known as a device ~or converting a mecha-nical Qtrain into an lectrical signal. Numeral 20 25 designates a ~oad cel~l embedded in a die 8, and numeral ~
21 designates a load cell embedded in a punch 7. ~ -` Numeral 22 designates a piezoelectric device mounted on ~; ~
.
~32~23 1 a frame 11. ~ signal produced from one of the sensors 20 to 22 is applied to a controller 9 and subjected to V-F conversion, or a signal subjected to A/D c~nversion is sampled and stored. A corresponding output of a machine strain sensor representing the particular load change is shown in Fig. 9. The waveform of Fig. g has a high-frequency noise elimin~ted by filter. The related operation is identical to those of embodiments 1 or 2.
Specifically, assume that the four steps of process shown in Fig. 10 are accomplished simultaneously in parallel way by each o~ the dies Q to ~ shown in Fig. 8. If a load cell is embedded in ~he punch 7 or ` "
each of the dies 8, outputs of the load cells are -detected in the waveforms Q to ~ corresponding to t~e respective steps ~ to ~ as shown in Fig. 11. A
plurality of these detection signals are processed in `
p~rallel by the operation of Embodiment 1 or 2 thereby to assure detection of an abnormal load with higher accuracy.
According to this embodiment also, the `
proximity switches l? and 18 may be mounted on the slide ram side.
~Embodiment 5) ~`;`
Another em~odiment in which a load change is detocted from mechanical strain is shown in Pig. 12.
A rotary pulse encoder 3 is mounted on a `
flywheel cran~shaft 2 of a former 1. A pulse produced 1329~9~23 1 from this encoder 3 is used as a reference pulse.
A linear pulse encoder 6 is mounted on a slide ram 5. A pulse produced from this encoder 6 is used as a detection pulse.
~he resolution of the pulse encoder is set in such a manner that a plurality of pulses from the rotary pulse encoder 3 are available between adjacent pulses of the linear pulse encoder during the operation of the slide ram 5. (That is to say, the more the pulses, the hiqher the resolution) Upon application of pressure on the work from the slide ram 5, a displacement strain is ~:`
generated in the machine, and therefore the motion of the slide ram 5 is substantially delayed, thereby lengthening the period of generation o~ a detection lS pulse as compared with a reference pulse. The period of `
the detection pulse faithfully reflects the speed change of the slide ram 5. The period of generation of the reference pulse, however, is not much affected in view of tbe fact that the change in rotational speed of the 20~fly~heel crankshaft 2 remains small due to the accumulated energy for rotations stored in tbe flywheel .
10. Fig. 13 shows the operation of a fault detection aocording to the present embodiment. Upon starting the proQ-urizing work, an origin detector built in the 25~ rotary pulse encoder~3 generates an origin pulse (a), and countèrs in the controller 9 are energized to start counting the referenoe pulses (b) from the rotary pulse sncoder 3 and the detection pulses te) or (f) from the ,~, '' ', ~ ", 1324~23 1 linear pulse encoder 6. In synchronism with the generation of a detection pulse, the controller 9 samples the count value of the reference pulses, and the value thus obtained is stored in memory. The count -value of detection pulses indicates the number of samplings of re$erence pulses directly or indirectly.
If the count value of detection pulses is not stored, means may be provided for identifying ~he sampling number by the address of a memory for storing the count value of reference pulses each time of sampling.
Sampling may not be ef~ected each time of generation of a detection pulse but for selected detection pulses.
After initial several pxessurizing work in normal ;~
operation, an averase count value o~ reference pulses (Xl, X2, so on~ ~or each count value ~Yl, Y2, so on) of aetection pulses is determined and stored in a memory as a standard value ~c) under normal operation. The count value of reference pulses may be either an integrated ~ .
~ ~alue from operation start to completion, or a count i, ~
~20 value in each s~mpling period reset each time and ` ``
fetched separateIy. A flowchart ~or determinlng an av rage value is shown in Fig. 14. Step~101 sees the generation of a detection pulse, and steps 102 and 103 ; Q le a count value~of reference pulses from`the : `
counter-~ and an integrated value of deteotion pulses ;a--ociated thèrewit~ and store them in a memory. On the a-sumption that an average value~for a number n of times `of normal presQurizing wor~ is determined, step 104 , .,:
``` 132~423 1 recognizes the end of a number n of pressurizing work cycles. Step 105 determines an average value by divid-ing by n the total for a nu~ber n of counts ~ a reference pulse count value for the same integrated value N of s detection pulses) for a number n of cycles. Step 106 stores the average value as a reference value in memory.
Reference pulses against detection pulses are naturally varied even in normal operation, and such variations are processed as a tolerance ~X) at the time of normal-abnormal decision mentioned below. If a fault such asdie breakage, cracking or wear or work grip failure occurs in actual pressurizing process, the load decreas-es suddenly, and therefore ~he feed rate of the slide ram 5 is instantaneously increased at the time of the lS fault as compared with in normal operation. AS a result, a detection pulse is generated earlier as shown -;
by dashed arrow in Fig~ 13(f). This causes some count values (Xl', X2', so on) of reference pulses at ~he time of generation of detection pulses ~X9') are deviated from the range of tolerance for normal operation. This relationship of ~eneration of detection pulses and reference pulses at the time of a fault ~f) and (g) is -Qtored in memory in advance. This data is compared with a reference value (c) for normal operation and, if the result exceeds a tolerance (~X) set in advance, a fault .
signal (h) indicating the generation of a fault is produced. The end of pressurizing work is recognized in software by setting the number of reference pulses to a ` ' ' .
- 17 - `
....
~;
.' . ; ~ . ` ' ,' ' ' ' , `'. ,, ' ' ` ' ` ~ ' .. ... ..
- 132~423 1 predetermined value. Upon generation of a fault signal (h), the air clutch in the flywheel lo is separated, and the pressurizing work stops instantaneously, thus preventing the pressurizing work from being repeated under abnormal condition. The number n of pressurizing operations for determining an average value as a reference val~e is performed by alternating between two methods selectively~ In one method, an average is taken for the first number n of pressuring work out of a plurality of pressuring operations continuously repeated and the value thus obtained is not updated until a predetermined number of pressuring operations is `
finished. In the other method, an average for a given number n of pressuring operations performed already is determined, and with the repetition of pressuring operations, a new number n of pressuring operations is selected to update the average value constantly. A
flowchart for the present embodiment is shown in Fig.
15. Step 101 checks to see whether a detection pulse is ganerated or not. If a generation of a detection pulse i~ recognized, steps 102 and 103 sample two pulse count values, which are then stored in memory. This process of operation is repeated unitl a cycle of pressurizing ~`
work is completed. Upon detection of the end of a cycle of pressurizing work at step 111, step 112 subtracts a reference pulse count value for the N-th sampling stored as a reference value ~from a reference pulse count value ~ ~`
for the N-th sampling (N: Integer), and if the result :. ~ . , .
132~423 1 of subtraction exceeds the tolerance X, step 113 produces a fault signal, while if the tolerance X is not exceeded, step 114 produces a signal for starting the -next cycle of pressurizing work. The number N of -samplings coincides with the integration value of detection pulses, and therefore a reference pulse for the N-th sampling is easily searched for within a memory. If an integration value of detection pulses is not used, the number N indicating the sampling number may be determined by a memory address. In such a case, step 103 is omitted. Unlike the present embodiment in which ~ount values of reference pulses associated with the generation of detection pulses are compared with each other, the increase or decrease in reference pulses may be determined by comparison between detection pulses as~another embodiment. a flowchart for determining an average value in such a case is obtained by changing steps lOS and 106 in Fig. 14 to have the contents of st ps 121 and 122 in Fig. 16 respectively. A flowchart for comparison according to the present embodiment is ` for seeing whether a tolerance X is exceeded by the .
difference between a reference value and a reference pulse count value for the N-th sampling less a reference pulse count value for the (N-l)th sampling. As a 2S further enbodiment, the count value of detection pulses may not be limited to àn integration value but the sum ~of a detection pulse count value and a reference pulse count value may be used for comparison or the difference , -- 19 -- .
' .
" ~ . ; P 7 132~23 1 between ~he ~wo pulse count values may be compared. A
flowchart for such a purpose is realized by changing the steps 105 in Fig. 14 and step 112 in Fig. 15 to determine the sum or difference between a detection pulse count value and a corresponding reference pulse count value. -`
(Embodiment 6~
~ his embodiment is so configured that more pulses are generated per unit time from a linear pulse encoder than from a rotary pulse encoder. No opera-tional problem is posed, however, if substantially the same number of pulses are produced from both pulse encoders. This configuration is identical to that shown in Fig. 12.
Fig. 18 is a diaqram for explaining the operation of fault detection according to the present embodiment. With the start of pressurizing work, an `~
origin pulse (a) is generated from an origin detector built in a rotary pulse encoder 3, and counters in a controller 9 begin to count reference pulses ~b) from a ` ~ rotary pulse encoder 3 and detection pulses (e) or (f) from a linear pulse encoder 6. The controller 9 samples a count value of detection pulses in synchronism with ~ ;
the generation of reference pulses, and values thus obt~ined are stored sequentially in memory. The count value of reference pulses indicates the number of samplings of detection pul~es directly or indirectly. -', :. '' ':
- 20 - ~ `
'."' .
132~423 1 If count values of reference pulses are not stored, the sampling number may be identified from the memory addresses stored each time of sampling of a count value of detection pulses. Sampling need not be effected for each reference pulse but for selected reference pulses.
nitially, ~n average count value (Yl, Y2, so on) of detection pulses for each count value ~Xl, X2, so on) of reference pulses is determined thro~gh several normal pressurizing operations, and is stored as a reference value (d) for normal operation in memory. The count value of detection pulses may be either an integration value frôm operation start to completion or a count value for each sampling sec~tion which is reset and fetched each time. A flowchart for determining an average count value is shown in Fig. 19. Step 201 checks to see whether a reference pulse is generated, ~nd upon recognition of the generation of a reference puise, steps 202 and 203 sample a count value of reference pulses and that of detection pulses and store them in memory. Assume that an average value is obtained by repeating normal pressurizing work a number n of times. Upon recongition of the end of a number n of pressuri2ing cycles at step 204, step 205 divides the total of a number n of count values (a count value of detection pulses for the same reference pulse integra-tion value N) for a number n of cycles by n thereby to determine an average value. Step 206 stores this average value in memory as a reference value. ~etection 132~423 1 pulses generat~d against reference pulses, which are naturally subj ected to variations even within a normal operation, are appropriately processed as a tolerance (iy) at the time of abnormal-normal decision mentioned below. If such a fault as die breakage, cracking or wear or work grip failure occurs in actual pressurizing process, the load is decreased suddenly, and therefore the feed rate of the slide ram 5 is instantaneously increased at the time point of the faul~ as compared ~ -10 with at the time of normal operation, resulting in `
detection pulses being generated earlier as shown in ~$). As a result, some count values tsuch as Y8') out~
of the count values (Yl', Y2', so on) of detection pulses at the time of generation of reference pulses are deviated from thè range of tolerance for normal operation. The relationship of generation between detection p~lses and reference pulses as designated in ~c) and (f) in abnormal operation is compared with the `
r~ference value ~d) for the normal operation stored in 20 ~e~ory, and if the result of comparison exceeds a ``
tolerancc ~y) set in advance, a fault signal th) indicating a fault is generated. The end of pressuri-zing work i-~ recognizable in software by setting the number of reference pulses to a predetermined level beforchand. Upon generation of a fault signal (h), an ;- ~ .. :.. :
~ air clutch in a flywheel 10 is separated, and the - ~ -pressurizing work is instantaneously Jtopped in such a manner as to inhibit the pressurizing work being `-. .
., .
. . ..
. . A . .
1324~23 repeated under abnormal conditions. A flowchart for the present embodiment is shown in Fig. 20. Step 201 checks to see whether a reference pulse is generated. upon recognition of a reference pulse generated, steps 202 and 203 sample ~wo pulse count values and store them in memory. This process of operation is repeated until the end of a cycle of pressurizing work is complete. Upon detection of the end of a cycle of pressurizing work at step 211, step 212 subtracts a detection pulse count value for the N-th sampling stored as a reference value from a count value of detection pulses for the N-th sampling (N: Integer), and if the result exceeds a tolerance y, step 213 produces a fault signal.
Otherwise, step 214 produces a signal for starting the `
next pressurizin~ work cycle~ The number N of samplings coincides with an integration value of reference pulses, and therefore detection pulses for the N-th sampling are easily searched for in the memory. In the case where any integration value o~ reference pulses is not used, 20 the valuè N may be determined also from the memory `
;address. In such a case, step 203 may be omitted.
Unlike in the present embodiment where count values o~
detection pulses against generation of reference pulses are compared with each other, the change in the number .
of detection pulses between reference pulses may be determin-d as another embodiment. A flowchart for determining an average value in such an embodiment is obtained by including steps 205 and 206 in Fig. 19 .
1 324~23 l changed to have the same contents as steps 221 and 222 in Fig. 21. In a flowchart for comparison process according to this embodiment, ~tep 212 in Fig. 20, as shown by step 231 of Fig. 22, is for checking to see whether the difference between the reference value and the detection pulse count value for the N-th sampling less the detection pulse count value for the (N-l)th sampling exceeds a tolerance y. According to a further embodiment, the count value of reference pulses is not -confined to an integration value, but the sum of a detection pulse count value and a reference pulse count value may be used for comparison or the difference between the two count values may be compared. A flow-chart associated wi~h such an embodiment is realized by including step 205 in Fig~ l9 and step 212 in Fig. 20 - for deter~ining the sum or difference between the reference pulse count value N and a corresponding `
detection pulse count value. `
Although embodiments of the present invention ~re expl~ined abo~e with reference to an abnormal load detection ~ystem for a former, the present inven~ion is applicable with equal effect also to other pressurizing .. .
apparatuse~ than the ~ormer.
. ~ ~
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1~24~23 1 apparatus in which a load change in the process of work deformation is determined by detecting the power consumption o~ a motor making up a power source, a mechanical strain of the former or a shock force of the pressurizing process by a sensor, and a signal thus obtained is converted into an electrical signal. The -power consumption is detected by detecting the effective power or the power factor indicating the ratio of effec-tive factor in the power consumption~ The elec~rical signal thus detected is continuously sampled and stored.
The stored value is compared with a normal value sampled previously~ I~ the dif$erence between the two values thus compared exceeds a tolerance, the pressurizing work is stopped. In detecting a load change from the power consumption of a motor, the power consumption is converted from analog to digital signals or from analog si~gnal to $requency, and pulses thus generated are counted by a counter. This count is based on the data representing the amount of shift of a slide ram in actual pressurizing work. The data representinq the shift of the slide ram is obtained as a pulse from an oscillator which derives a starting pulse from a trigger -~
pulse generated at a predetermined position of the slide r~ or a flywheel. Such a pulse may alternatively be ~"
obtained from a linear pulse encoder mounted on a slide ram or a rotary pulse encoder mounted on a crankshaft for converting the rotational energy of a motor into the linear motion o$ the slide ram. This pulse is used as a - 3 - `
' :`, 2~423 1 reference pul~e for determining the timing of sampling.
The V-F (voltage-frequency) of A/D conversion, counting of pulses, comparison and generation of a signal upon detection of a fault, are all effec~ed by a controller includinq a CPU, a RAM, a ROM, an I/O interface, or other processing devices having the required functions.
The object of the present invention for de~ecting a load change from the mechanical strain of the former is attained by sampling an output of a strain gauqe mounted on the former body.
Accor~ing to another method of detecting a load change from a mechanical strain, a pulse encoder is mounted both on a flywheel crankshaft of a power source in rotary ~otion and on a slide ram for converting the 15 rotational kinetic energy into a linear kinetic energy `~
which is used for actual pressurizing work. A pulse `
signal from a rotary pulse encoder mounted on ~he ,~
flywh el cran~shaft for~detecting an angular displace-ment of the crankshaft and a pulse signal from a linear pulse encoder for detecting the displacement of the linear motion of the slide ram are counted, processed, comparea and sub~ected to such procèss as normal-~bnormal decision, so that the difference in the number ; ~ of pulses produced under an abnormal load is used to 2S ~d~tect a oase of fault or abnormal condition, thus ` ~ producing a ~ault signal for suspendlng the pressurizing -work. The controller has built therein a CPU, a RAM as data memory, a ROM a~ program storage memory, a counter, ~ : : .. .
. : .
1~24423 1 and other processing devices having the required functions.
The object of the present invention for detecting a load change from an impact force is attained by sampling an output from a load cell embedded in the punch or die side.
According to an apparatus and a method of the present invention, a detected load change is sampled at a plurality of points for detecting an abnormal load, and therefore a very small abnoraml load condition including the breakage, cracking or wear of a die or displacement due to work grip failure which may develop during the pressurizing work and have an adverse ef~ect on the work processing is easily and accurately detected.
According to a method of the present invention utili2ing a mechanical strain, the displacement due ~o ;
meohanical strain which may develop between the ~lywheel crankshaft and the slide ram of the machine during the pres-uri~ing work is used as a signal representing a load condition, and the displacement due to strain is detected ~s a phase difference between pulæes genera~ed by two pulse encoders or more accurately as a difference in the number of pulses generated therebetween. It is thus possible to detect even a qlight change in load s~gnal with high sensitivity as a large amount of dis-placement, thereby assuring detection of high resolution of an abnormal load.
_ 5 _ :' ~ .
- . . .
`` 1324423 The invention may be suDmarized according to a firæt broad aspect as an abnormal load detection apparatus for a pressurizing apparatus, co~prlsing, power generatlon ~eanæ adapted for rotational ~otlon and including a motor; converter ~eans for convertlng the rotative kinetic energy into linear klnetlc energy;
pressurizlng ~eans for applying the llnear kinetic energy to the work; ~eans for detecting a cbange in the load l~posed on the work and converting it into an electrical signal; means for sampling ~ `
sald electrlcal signal at selected one of a plurality of ` `
pressurlzing positions and a plurallty of pressurizlng tlme points; ~ean~ for storlng a nor~al value of the electrical signal corresponding to sald sarpllng points; means for coDparlng a value obtalned by sald sarpling ~lth the nor~al value stored; and means ~` `
for deciding on an abnor~al load oondltion ~hen the result of sald conpari~on exceed~ a predeter~ined ~alue~
Accord1ng to a ~econd broad a~pect of the inventlon, there i~ provlded an abnor~al load detection apparatus for a pre~urizing ~pparatus, co~pri~ing po~er generation ~eans adapted `-for rotational ~otlon; con~er~lon reans for convertlng the -rotatlonal ~ln~tic energy into the linear kinetlc energy;
prQ~urlzlng nean~ adapted for linear ~otlon by the linear klnetlc energy; ~eans for detecting the di~placerent due to a ~echanlcal ~ -~train bet~een ~ald pre~urlzlng uean~ and ~aid po~er generation , n~an~ a~ a signal representing a load conditlon under -`
. . . .
pre~urlzatlon, ~aid ~ean~ for detectlng lncludlng means for detectlng the anount of rotational dl~place~ent of a rotary shaft ... . .
ln rotational aotlon and ~aan~ for detectlng the a~ount of llnear .
5a , . ..
132442~
displacement of said pressurizing ~eans; means for sampling and storing the amount of rotational displacement and the a~ount o$
linear displace~ent at predeterD~ned regular tlDe intervals in a pressurizin~ process; means for co~paring the amount of rotatlonal displace~ent and the a~ount of linear displace~ent ~tored as above wlth the amount of rotational displacement and the amount of linear displaceDent sampled anew in a new pressurizing process and neans for producing a signal notifying a fault when the amount of rotational displace~ent and the a~ount of llnoar displace~ent sa~pled anew exceed t~e a~ount of rotational dlsplace~ent and the aJount of llnear displace~ent stored respectively by a `
predeternined tolerance Accordlng to a third broad aspect of the invention t~ere i8 provided a ~et~od of abnoraal load detection co~prlslng the step of detecting a load change of the ~ork and converting the detectlon lnto an electrical signal; the step of ~anpllng the eleotrical signal converted at ~elected one of a plurallty of pressur~zlng positlons and a plurality of points of pre~surlzlng tl~e~ t~e step of co~paring the sanple value uith a noraal value of the electrlcal slgnal correspondlng to the sa~pling polnt) and t~e step of decldlng on an abnornal load conditlon when the result of conparlson exceeds a predeter~ined toleran¢e Accordlng to a fourth broad aspect of the present lnventlon there ls provld~d a nethod of abnor~al load detectlon `~
for a pressurlzlng apparatus covprl~lng power generat~on ~eans adapted for rotational ~otlon nean~ for convertlng the rotational klnetlc energy lnto the linear kinetic energy and pre~surlzlng . ~ ~ . .
C 5b ~ ,' 1324~23 means adapted for linear motion by the linear kinetic energy, said method comprising the steps of counting the number of pulses generated by a pulse encoder for detecting the aDount of rotational displacement of a rotary shaft in rotatlonal Dotion, counting the nuDber of pulses generated by a pulse encoder for detecting the amount of linear displacement of the pressurizing means~ and detecting an abnoraal load condition from the difference between the count values generated fro~ said two pulse encoders. : `
. `' '.
. . .
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''~'~;`'',''.' 132~423 1 BRIEF DESCRIPl~ION OF THE DRAWINGS
Fig. 1 is a diagram showing an example of configuration utilizing the effective power according to an embodiment of the presen~ invention.
Fig. 2 is a diagram for explaining the opera-tion of the embodiment shown in Fig. 1.
Fig. 3 and Fig. 4 are flowcharts of programs for executing the operation of the embodiment shown in Fig~ 2.
Fig. 5 is a diagram showing another embodimen~
of the present inven~ion u~ilizing the effective power.
Fig. 6 is a diagram for explaining the opera-tion of the embodimen~ shown in Fig. 5.
Fig. 7 iS a diagram showing still another embodiment of the invention utilizing the effective power.
Fig. 8 is a diagram showing still another embodiment of the invention utilizing the mechanical strain.
Fig. 9 is a sensor output diagram according to ~n embodiment of the present invention.
Fig. 10 is a diagram showing specific steps of the pressurizing work.
Fig. 11 is~a diagram showing an output of a :
~ ~25 ensor produced at each processing step shown in Fig.
~ 10.
Fig. 12 is a diagram showing still another embodiment of the invention utilizing the mechanical .:, 132442~
1 strain.
Fig. 13 is a diagram for explaining the operation of the embodiment shown in Fig. 12.
Fig. 14 and Fig. 15 are flowcharts based on the operation explained in Fig. 13.
Fig. 16 and Fig. 17 are flowcharts showing ~-another embodiment of means for abnormal load decision.
Fig. 18 is a diagram for explaining the opera-tion of still another embodiment having the configura-10 tion shown in Fig. 12. ~ ;
Fig. 19 and Fiq. 20 are flowcharts based on `-the operation explained in Fiq. 18.
Fig. 21 and Fig. 22 are flowcharts showing another embodiment for abnormal load decision. `
15 DESCRIPTION OF THE PR~FERRED EMBODIMENTS `.``.
Fig. 1 shows an example of configuration of `
th- present invention in which a load change is detected ``
fro~ the power consumption of a motor and a referen~e p~lse is obtained from an oæcillator in a controller 9. .`
Num~ral 1 designates a former body. The rotational energy of a motor 15 is tranæmitted through a pulley 14 and`a shaft 12 to a flywheel 10 and stored therein. A
- : ~
flywh el cran~shaft 2 is connected to a slide ram 5 by a connecting rod 4, so that the turning effort 12 of the ~ .
25 "flywhe-l crankshaft 2 is converted into a linear motion `~
13 of the slide ram 5. ~ punch 7 is mounted at the -for~Ard end of the sllde ram 5, a die 8 is arranged on a , .
7 ~ ' . ~
132~423 1 frame 11 of a former 1 at a position in opposed relations with the punch 7. A proximity switch element 17 for generating a trigger pulse providing a start pulse for the oscillator in the controller 9 and a sensor 18 therefor are mounted on the flywheel 10. The motor 15 is connected with a power consumption detection means 16 for detecting the effective power EI cos~ of the power consumption.
Fig. 2 shows the operation within the con-troller 9. This operation is entirely controlled by a program under the control of a CPU. A power consumption waveform for the pressurizing work assumes a smooth form as shown in Fig. ~(a) as an actual load change is somewhat integrated by the energy storage-discharge `
15 function of the flywheel 10. The power consumption `
waveform (a) is detected as a load change waveform by a power consumption detection means 16. The output thus produced is subjected to a V-F conversion, thereby producing a detection pulse output higher in frequency for a high power consumption as shown in (b). When the flywheel 10 rotates with the proximity switch element 17 passing through the ~ensor 18, the oscillator pulse of (c) is generated. This start pulse couses the oscil-lator w~thin the controller 9 to be enèrgized thereby to generate a pulse shown in ~d) at reqular intervals of .
time. This pulse provides a re~erence used as a sampl-ing pulse for counting detection pulses. A reference pulse may alternatively be generated at predetermined ` ' ' - 8 - ~
1~2~423 l intervals of time by counting the time in accordance with a program instead of by using an oscillator. The count value of detection pulses is sampled and stored each time of generation of a reference pulse. The detection pulse count value may be reset each time of generation of a reference pulse or an integrated value~
An example of reset~ing a counter each time a reference pulse is generated is shown in ~e). The number of samplings is determined appropriately in advance by a program taking into consideration the time at which the change area of power consumption charged in the flywheel is capable of being caught, or a detection point.
A reference value is obtained by conducting the normal pressuri~ing work several times and averaging ~ -the count value of the detection pulses sampled for each reference pulse. The several pressurizing work for ; `
dotermining a reference value may be either initial several ones or given s-veral ones of all the work that ;~ have ~lready been conducted. As another alternative, an .
appropriate value may be written as a part of the program. A reference value is stored as Al, A2 and so on of ~f). In actual pressurizing process, each time a reference pulse is genèrated, tho count value of detec-tion pulses sampled is compared with a reference value.
If an abnormal load condition occurs as shown by dashed line in the waveform (a~, the nùmber of pulses at or around the time point of abnormal load occurrence increases as shown in (g). At this time, the detection ..;':`'':
, .: .
_ 9 _ ~ 324423 1 pulse count value A'5 shown in (h) is compared with a reference value A5, and if the difference therebetween exceeds a tolerance (x), a fault signal (i) is generated thereby to stop the pressurizing work.
Program flowcharts are shown in Figs . 3 and 4.
The flowchart of Fig. 3 is for determining a reference value. step 31 monitors the generation of a reference pulse, and upon generation of a reference pulse, step 32 stores the count value of detection pulses. Then, the integrated value of reference pulses is stored àt step 33. Instead of storing an integrated value of reference pulses, the sampling number may be identified by the address of a memory for storing the count value of detection pulses each time of sampling thereof. Sampl-ing is not necessarily effected each time of generationof a reference pulse but by a selected reference pulse.
In order to determine an average value for a number n of normal pressurizing work repeated, step 34 monitors whether a number n of pressurizing work has been com-pleted. At the end of a number n of pressurizing work,step 35 determines an average value of counts of the detection pulses for the same integrated value N of reference pulses associated with the number n of normal operations, and step 36 qamples the average value and stores it as a reference value for the N-th dètection pulse count.
A flowchart of a program for decision on abnormal load is shown in Fig. 4. Steps 31 and 32 :
~, ' .
132~23 1 sample a detection pulse count value from the N-th reference pulse. Step 41 reads the reference value for the N-th sampling from the memory, and step 42 deter-mines the difference between the sampled value ana the reference value, wAile at the same time checking to see whether the result of comparison exceeds the tolerance X
assuring that the work piece is capable of being processed within the tolerance. If the difference exceeds the tolerance x, step 43 decides that a fault has occurred and produces a $ault signal. If the difference does not exceed the tolerance x, step 44 starts the next pressurizing ~-ork.
- In this embodiment, proximity switches 17 and 18 may be mounted on the slide ram 5 and the frame 11 15 respectively. ` "`
(Embodiment 2) Power consumption may be detected as an analog : `
value and sub~ ected to analog-to-digital instead of voltage-to-frequency conversion and may be stored in .
digital form. A circuit configuration for such a method is s~own in Fig. 5, and the operation thereof in Fig. 6. `~
A start pulse shown in ~b) is generated by proximity -sensors 17, 18 or a program, and with this time point as a reference, an output signal of a power consumption 25 detection sensor representing a load change is sampled. -The sampling value is subjected to A/D conversion and stored in memory. Reference values are stored as Bl, ~
' "' "` ' - 11 - . ~.
'.'''. '~
132~ 23 1 B2, SO on as shown in (d). The reference value is determined in the same manner as in Embodiment 1. Each time of pressurizing work, the sampled analog signal is subjected to A/D conversion, and is stored as Bl', B2', so on as shown in (e). If an abnormal load occurs as shown by the dashed line in Fig. 6, the A/D conversion value Bn' undergoes a considerable change, and if the difference thereof with the reference value Bn exceeds a tolerance X, a fault signal shown in (f) is generated thereby to stop the pressurizing operation.
A flowchart for the aforementioned operation is obtained by replacing the count value of detection pulses with an A/D conversion value in Figs. 3 and 4~
In the prccess of comparison, each A/D con-version value may be compared with each corresponding reference value, or the sum o~ a predetermined continuous number of A/D conversion values may be compared with a corresponding normal value. As another alternative, an integr~ted value of A/D conversion `` `
values may be compared with a corresponding normal value for each predetermined number of samplings. ` `
The above-mentioned methods o~ comparison o~ ~-A4D converQion value are applicable also to all other embodiments.
The proximity switches 17, 18 may be mounted on the slide ram side.
. . ,' ."', .. ..
132~23 1 (Embodiment 3) Fig. 7 shows ano~her embodiment in which a load change is detected from the power consumption of a motor and a reference pulse is produced from a rotary pulse encoder 3 mounted on a flywheel crankshaft 2. If a rotary pulse encoder having a start pulse built therein is used in this embodiment, the oscillator in `.
the controller and the proximity switch for generating the start pulse of the oscillator are eliminated. The operation of this embodiment is identical to that of Fig~ 2 lacking the oscillator start pulse (c). The flowchart of the program of this embodiment is the same `
as Figs. 3 and 4.
The same object o~ operation is also achieved by a linear pulse encoder 6 having a start pulse built therein mounted on the slide ram side instead of a rotary pulse encoder. ~
', ' (~mbodiment 4 An embodiment in which a load change is detected from mechanical strain by a sensor which converts the load change into an electrical siqnal is s~own in ~ig. 8. A load cell or a piezoelectric device is generally known as a device ~or converting a mecha-nical Qtrain into an lectrical signal. Numeral 20 25 designates a ~oad cel~l embedded in a die 8, and numeral ~
21 designates a load cell embedded in a punch 7. ~ -` Numeral 22 designates a piezoelectric device mounted on ~; ~
.
~32~23 1 a frame 11. ~ signal produced from one of the sensors 20 to 22 is applied to a controller 9 and subjected to V-F conversion, or a signal subjected to A/D c~nversion is sampled and stored. A corresponding output of a machine strain sensor representing the particular load change is shown in Fig. 9. The waveform of Fig. g has a high-frequency noise elimin~ted by filter. The related operation is identical to those of embodiments 1 or 2.
Specifically, assume that the four steps of process shown in Fig. 10 are accomplished simultaneously in parallel way by each o~ the dies Q to ~ shown in Fig. 8. If a load cell is embedded in ~he punch 7 or ` "
each of the dies 8, outputs of the load cells are -detected in the waveforms Q to ~ corresponding to t~e respective steps ~ to ~ as shown in Fig. 11. A
plurality of these detection signals are processed in `
p~rallel by the operation of Embodiment 1 or 2 thereby to assure detection of an abnormal load with higher accuracy.
According to this embodiment also, the `
proximity switches l? and 18 may be mounted on the slide ram side.
~Embodiment 5) ~`;`
Another em~odiment in which a load change is detocted from mechanical strain is shown in Pig. 12.
A rotary pulse encoder 3 is mounted on a `
flywheel cran~shaft 2 of a former 1. A pulse produced 1329~9~23 1 from this encoder 3 is used as a reference pulse.
A linear pulse encoder 6 is mounted on a slide ram 5. A pulse produced from this encoder 6 is used as a detection pulse.
~he resolution of the pulse encoder is set in such a manner that a plurality of pulses from the rotary pulse encoder 3 are available between adjacent pulses of the linear pulse encoder during the operation of the slide ram 5. (That is to say, the more the pulses, the hiqher the resolution) Upon application of pressure on the work from the slide ram 5, a displacement strain is ~:`
generated in the machine, and therefore the motion of the slide ram 5 is substantially delayed, thereby lengthening the period of generation o~ a detection lS pulse as compared with a reference pulse. The period of `
the detection pulse faithfully reflects the speed change of the slide ram 5. The period of generation of the reference pulse, however, is not much affected in view of tbe fact that the change in rotational speed of the 20~fly~heel crankshaft 2 remains small due to the accumulated energy for rotations stored in tbe flywheel .
10. Fig. 13 shows the operation of a fault detection aocording to the present embodiment. Upon starting the proQ-urizing work, an origin detector built in the 25~ rotary pulse encoder~3 generates an origin pulse (a), and countèrs in the controller 9 are energized to start counting the referenoe pulses (b) from the rotary pulse sncoder 3 and the detection pulses te) or (f) from the ,~, '' ', ~ ", 1324~23 1 linear pulse encoder 6. In synchronism with the generation of a detection pulse, the controller 9 samples the count value of the reference pulses, and the value thus obtained is stored in memory. The count -value of detection pulses indicates the number of samplings of re$erence pulses directly or indirectly.
If the count value of detection pulses is not stored, means may be provided for identifying ~he sampling number by the address of a memory for storing the count value of reference pulses each time of sampling.
Sampling may not be ef~ected each time of generation of a detection pulse but for selected detection pulses.
After initial several pxessurizing work in normal ;~
operation, an averase count value o~ reference pulses (Xl, X2, so on~ ~or each count value ~Yl, Y2, so on) of aetection pulses is determined and stored in a memory as a standard value ~c) under normal operation. The count value of reference pulses may be either an integrated ~ .
~ ~alue from operation start to completion, or a count i, ~
~20 value in each s~mpling period reset each time and ` ``
fetched separateIy. A flowchart ~or determinlng an av rage value is shown in Fig. 14. Step~101 sees the generation of a detection pulse, and steps 102 and 103 ; Q le a count value~of reference pulses from`the : `
counter-~ and an integrated value of deteotion pulses ;a--ociated thèrewit~ and store them in a memory. On the a-sumption that an average value~for a number n of times `of normal presQurizing wor~ is determined, step 104 , .,:
``` 132~423 1 recognizes the end of a number n of pressurizing work cycles. Step 105 determines an average value by divid-ing by n the total for a nu~ber n of counts ~ a reference pulse count value for the same integrated value N of s detection pulses) for a number n of cycles. Step 106 stores the average value as a reference value in memory.
Reference pulses against detection pulses are naturally varied even in normal operation, and such variations are processed as a tolerance ~X) at the time of normal-abnormal decision mentioned below. If a fault such asdie breakage, cracking or wear or work grip failure occurs in actual pressurizing process, the load decreas-es suddenly, and therefore ~he feed rate of the slide ram 5 is instantaneously increased at the time of the lS fault as compared with in normal operation. AS a result, a detection pulse is generated earlier as shown -;
by dashed arrow in Fig~ 13(f). This causes some count values (Xl', X2', so on) of reference pulses at ~he time of generation of detection pulses ~X9') are deviated from the range of tolerance for normal operation. This relationship of ~eneration of detection pulses and reference pulses at the time of a fault ~f) and (g) is -Qtored in memory in advance. This data is compared with a reference value (c) for normal operation and, if the result exceeds a tolerance (~X) set in advance, a fault .
signal (h) indicating the generation of a fault is produced. The end of pressurizing work is recognized in software by setting the number of reference pulses to a ` ' ' .
- 17 - `
....
~;
.' . ; ~ . ` ' ,' ' ' ' , `'. ,, ' ' ` ' ` ~ ' .. ... ..
- 132~423 1 predetermined value. Upon generation of a fault signal (h), the air clutch in the flywheel lo is separated, and the pressurizing work stops instantaneously, thus preventing the pressurizing work from being repeated under abnormal condition. The number n of pressurizing operations for determining an average value as a reference val~e is performed by alternating between two methods selectively~ In one method, an average is taken for the first number n of pressuring work out of a plurality of pressuring operations continuously repeated and the value thus obtained is not updated until a predetermined number of pressuring operations is `
finished. In the other method, an average for a given number n of pressuring operations performed already is determined, and with the repetition of pressuring operations, a new number n of pressuring operations is selected to update the average value constantly. A
flowchart for the present embodiment is shown in Fig.
15. Step 101 checks to see whether a detection pulse is ganerated or not. If a generation of a detection pulse i~ recognized, steps 102 and 103 sample two pulse count values, which are then stored in memory. This process of operation is repeated unitl a cycle of pressurizing ~`
work is completed. Upon detection of the end of a cycle of pressurizing work at step 111, step 112 subtracts a reference pulse count value for the N-th sampling stored as a reference value ~from a reference pulse count value ~ ~`
for the N-th sampling (N: Integer), and if the result :. ~ . , .
132~423 1 of subtraction exceeds the tolerance X, step 113 produces a fault signal, while if the tolerance X is not exceeded, step 114 produces a signal for starting the -next cycle of pressurizing work. The number N of -samplings coincides with the integration value of detection pulses, and therefore a reference pulse for the N-th sampling is easily searched for within a memory. If an integration value of detection pulses is not used, the number N indicating the sampling number may be determined by a memory address. In such a case, step 103 is omitted. Unlike the present embodiment in which ~ount values of reference pulses associated with the generation of detection pulses are compared with each other, the increase or decrease in reference pulses may be determined by comparison between detection pulses as~another embodiment. a flowchart for determining an average value in such a case is obtained by changing steps lOS and 106 in Fig. 14 to have the contents of st ps 121 and 122 in Fig. 16 respectively. A flowchart for comparison according to the present embodiment is ` for seeing whether a tolerance X is exceeded by the .
difference between a reference value and a reference pulse count value for the N-th sampling less a reference pulse count value for the (N-l)th sampling. As a 2S further enbodiment, the count value of detection pulses may not be limited to àn integration value but the sum ~of a detection pulse count value and a reference pulse count value may be used for comparison or the difference , -- 19 -- .
' .
" ~ . ; P 7 132~23 1 between ~he ~wo pulse count values may be compared. A
flowchart for such a purpose is realized by changing the steps 105 in Fig. 14 and step 112 in Fig. 15 to determine the sum or difference between a detection pulse count value and a corresponding reference pulse count value. -`
(Embodiment 6~
~ his embodiment is so configured that more pulses are generated per unit time from a linear pulse encoder than from a rotary pulse encoder. No opera-tional problem is posed, however, if substantially the same number of pulses are produced from both pulse encoders. This configuration is identical to that shown in Fig. 12.
Fig. 18 is a diaqram for explaining the operation of fault detection according to the present embodiment. With the start of pressurizing work, an `~
origin pulse (a) is generated from an origin detector built in a rotary pulse encoder 3, and counters in a controller 9 begin to count reference pulses ~b) from a ` ~ rotary pulse encoder 3 and detection pulses (e) or (f) from a linear pulse encoder 6. The controller 9 samples a count value of detection pulses in synchronism with ~ ;
the generation of reference pulses, and values thus obt~ined are stored sequentially in memory. The count value of reference pulses indicates the number of samplings of detection pul~es directly or indirectly. -', :. '' ':
- 20 - ~ `
'."' .
132~423 1 If count values of reference pulses are not stored, the sampling number may be identified from the memory addresses stored each time of sampling of a count value of detection pulses. Sampling need not be effected for each reference pulse but for selected reference pulses.
nitially, ~n average count value (Yl, Y2, so on) of detection pulses for each count value ~Xl, X2, so on) of reference pulses is determined thro~gh several normal pressurizing operations, and is stored as a reference value (d) for normal operation in memory. The count value of detection pulses may be either an integration value frôm operation start to completion or a count value for each sampling sec~tion which is reset and fetched each time. A flowchart for determining an average count value is shown in Fig. 19. Step 201 checks to see whether a reference pulse is generated, ~nd upon recognition of the generation of a reference puise, steps 202 and 203 sample a count value of reference pulses and that of detection pulses and store them in memory. Assume that an average value is obtained by repeating normal pressurizing work a number n of times. Upon recongition of the end of a number n of pressuri2ing cycles at step 204, step 205 divides the total of a number n of count values (a count value of detection pulses for the same reference pulse integra-tion value N) for a number n of cycles by n thereby to determine an average value. Step 206 stores this average value in memory as a reference value. ~etection 132~423 1 pulses generat~d against reference pulses, which are naturally subj ected to variations even within a normal operation, are appropriately processed as a tolerance (iy) at the time of abnormal-normal decision mentioned below. If such a fault as die breakage, cracking or wear or work grip failure occurs in actual pressurizing process, the load is decreased suddenly, and therefore the feed rate of the slide ram 5 is instantaneously increased at the time point of the faul~ as compared ~ -10 with at the time of normal operation, resulting in `
detection pulses being generated earlier as shown in ~$). As a result, some count values tsuch as Y8') out~
of the count values (Yl', Y2', so on) of detection pulses at the time of generation of reference pulses are deviated from thè range of tolerance for normal operation. The relationship of generation between detection p~lses and reference pulses as designated in ~c) and (f) in abnormal operation is compared with the `
r~ference value ~d) for the normal operation stored in 20 ~e~ory, and if the result of comparison exceeds a ``
tolerancc ~y) set in advance, a fault signal th) indicating a fault is generated. The end of pressuri-zing work i-~ recognizable in software by setting the number of reference pulses to a predetermined level beforchand. Upon generation of a fault signal (h), an ;- ~ .. :.. :
~ air clutch in a flywheel 10 is separated, and the - ~ -pressurizing work is instantaneously Jtopped in such a manner as to inhibit the pressurizing work being `-. .
., .
. . ..
. . A . .
1324~23 repeated under abnormal conditions. A flowchart for the present embodiment is shown in Fig. 20. Step 201 checks to see whether a reference pulse is generated. upon recognition of a reference pulse generated, steps 202 and 203 sample ~wo pulse count values and store them in memory. This process of operation is repeated until the end of a cycle of pressurizing work is complete. Upon detection of the end of a cycle of pressurizing work at step 211, step 212 subtracts a detection pulse count value for the N-th sampling stored as a reference value from a count value of detection pulses for the N-th sampling (N: Integer), and if the result exceeds a tolerance y, step 213 produces a fault signal.
Otherwise, step 214 produces a signal for starting the `
next pressurizin~ work cycle~ The number N of samplings coincides with an integration value of reference pulses, and therefore detection pulses for the N-th sampling are easily searched for in the memory. In the case where any integration value o~ reference pulses is not used, 20 the valuè N may be determined also from the memory `
;address. In such a case, step 203 may be omitted.
Unlike in the present embodiment where count values o~
detection pulses against generation of reference pulses are compared with each other, the change in the number .
of detection pulses between reference pulses may be determin-d as another embodiment. A flowchart for determining an average value in such an embodiment is obtained by including steps 205 and 206 in Fig. 19 .
1 324~23 l changed to have the same contents as steps 221 and 222 in Fig. 21. In a flowchart for comparison process according to this embodiment, ~tep 212 in Fig. 20, as shown by step 231 of Fig. 22, is for checking to see whether the difference between the reference value and the detection pulse count value for the N-th sampling less the detection pulse count value for the (N-l)th sampling exceeds a tolerance y. According to a further embodiment, the count value of reference pulses is not -confined to an integration value, but the sum of a detection pulse count value and a reference pulse count value may be used for comparison or the difference between the two count values may be compared. A flow-chart associated wi~h such an embodiment is realized by including step 205 in Fig~ l9 and step 212 in Fig. 20 - for deter~ining the sum or difference between the reference pulse count value N and a corresponding `
detection pulse count value. `
Although embodiments of the present invention ~re expl~ined abo~e with reference to an abnormal load detection ~ystem for a former, the present inven~ion is applicable with equal effect also to other pressurizing .. .
apparatuse~ than the ~ormer.
. ~ ~
~ ....
,.:
- 2g ~
.. . .
Claims (43)
1 An abnormal load detection apparatus for a pressurizing apparatus, comprising:
power generation means adapted for rotational motion and including a motor;
converter means for converting the rotative kinetic energy into linear kinetic energy;
pressurizing means for applying the linear kinetic energy to the work;
means for detecting a change in the load imposed on the work and converting it into an electrical signal;
means for sampling said electrical signal at selected one of a plurality of pressurizing positions and a plurality of pressurizing time points;
means for storing a normal value of the electrical signal corresponding to said sampling points;
means for comparing a value obtained by said sampling with the normal value stored; and means for deciding on an abnormal load condition when the result of said comparison exceeds a predetermined value.
power generation means adapted for rotational motion and including a motor;
converter means for converting the rotative kinetic energy into linear kinetic energy;
pressurizing means for applying the linear kinetic energy to the work;
means for detecting a change in the load imposed on the work and converting it into an electrical signal;
means for sampling said electrical signal at selected one of a plurality of pressurizing positions and a plurality of pressurizing time points;
means for storing a normal value of the electrical signal corresponding to said sampling points;
means for comparing a value obtained by said sampling with the normal value stored; and means for deciding on an abnormal load condition when the result of said comparison exceeds a predetermined value.
2. An apparatus according to Claim 1, wherein said means for detecting a load change and converting it into an electrical signal includes means for detecting the power consumption of said motor.
3 An apparatus according to Claim 2, wherein said means for detecting the power consumption and converting it into an electrical signal includes means for converting the power consumption detected into a voltage according to the magnitude of the power, means for converting the voltage into a frequency and means for counting the frequency; and, said sampling means includes means for sampl-ing a count value of said counter.
4. An apparatus according to Claim 1, wherein said means for detecting a load change and converting it into an electrical signal includes means for converting a mechanical strain into an electrical signal.
5. An apparatus according to Claim 4, wherein said means for converting a mechanical strain into an electrical signal includes means for converting the electrical signal into a frequency and means for counting the frequency, and said sampling means includes means for sampl-ing a count value of said counter.
6. An apparatus according to Claim 3 or 5, wherein said counting means includes means for counting the number of pulses generated between predetermined sampling processes as an output of said voltage-frequency conversion.
7. An apparatus according to Claim 3 or 5, wherein said counting means includes means for integrating and counting the number of pulses of said voltage-frequency conversion output.
8. An apparatus according to any one of Claims 1, 2 and 4, wherein said sampling means includes means for analog-digital (A/D) conversion of the electrical signal and means for storing a value obtained by the A/D
conversion.
conversion.
9. An apparatus according to Claim 8, wherein said comparator means includes means for adding a prede-termined number of A/D conversion values and means for comparing the sum obtained with the normal value.
10. An apparatus according to Claim 3 or 5, wherein said sampling means includes:
means for detecting the rotational position of a power generation section in rotational motion;
pulse generation means operated by a signal from said rotational position detection means; and means for sampling the count value by a pulse from said pulse generation means.
means for detecting the rotational position of a power generation section in rotational motion;
pulse generation means operated by a signal from said rotational position detection means; and means for sampling the count value by a pulse from said pulse generation means.
11. An apparatus according to Claim 10, wherein said pulse generation means includes an oscillator.
12. An apparatus according to Claim 10, wherein said pulse generation means includes means for counting the time according to a program.
13. An apparatus according to Claim 3 or 5, wherein said sampling means includes:
means for detecting the position of a pressurizing section in linear motion;
pulse generation means energized by a signal from said position detection means; and means for sampling the count value by a pulse from said pulse generation means.
means for detecting the position of a pressurizing section in linear motion;
pulse generation means energized by a signal from said position detection means; and means for sampling the count value by a pulse from said pulse generation means.
14. An apparatus according to Claim 13, wherein said pulse generation means includes an oscillator.
15. An apparatus according to Claim 13, wherein said pulse generation means includes means for counting the time according to a program.
16. An apparatus according to Claim 8, wherein said sampling means includes:
means for detecting the rotational position of the power generation section in rotational motion;
pulse generation means energized by a signal from said rotational position detection means; and means for sampling the electrical signal by a pulse from the pulse generation means.
means for detecting the rotational position of the power generation section in rotational motion;
pulse generation means energized by a signal from said rotational position detection means; and means for sampling the electrical signal by a pulse from the pulse generation means.
17. An apparatus according to Claim 16, wherein said pulse generation means includes an oscillator.
18 An apparatus according to Claim 16, wherein said pulse generation means includes means for counting the time according to a program.
19. An apparatus according to Claim 8, wherein said sampling means includes:
means for detecting the position of said pressurizing section in linear motion;
pulse generation means energized by a signal from said position detection means; and means for sampling the electrical signal by a pulse from said pulse generation means.
means for detecting the position of said pressurizing section in linear motion;
pulse generation means energized by a signal from said position detection means; and means for sampling the electrical signal by a pulse from said pulse generation means.
20. An apparatus according to Claim 19, wherein said pulse generation means includes an oscillator.
21. An apparatus according to Claim 19, wherein said pulse generation means includes means for counting the time according to a program.
22. An apparatus according to Claim 3 or 5, wherein said sampling means includes means mounted on a rotary shaft of the power generation section in rotary motion for performing the sampling operation by a pulse from a rotary pulse encoder.
23. An apparatus according to Claim 3 or 5, wherein said sampling means includes means mounted on the pressurizing section in linear motion for performing the sampling operation by a pulse from a linear pulse encoder.
24. An apparatus according to Claim 4 or 5, wherein said means for converting a mechanical strain into an electrical signal is mounted on a frame of the pressurizing apparatus.
25. An apparatus according to Claim 4 or 5, wherein said means for converting a mechanical strain into an electrical signal is embedded in a part where the work is pressurized.
26. An apparatus according to any one of Claims 1 to 5, wherein said means for determining a normal value includes means for determining an average value of the sampling values obtained from a plurality of pressurizing processes.
27. An abnormal load detection apparatus for a pressurizing apparatus, comprising:
power generation means adapted for rotational motion;
conversion means for converting the rotational kinetic energy into the linear kinetic energy;
pressurizing means adapted for linear motion by the linear kinetic energy;
means for detecting the displacement due to a mechanical strain between said pressurizing means and said power generation means as a signal representing a load condition under pressurization, said means for detecting including means for detecting the amount of rotational displacement of a rotary shaft in rotational motion and means for detecting the amount of linear displacement of said pressurizing means;
means for sampling and storing the amount of rotational displacement and the amount of linear displacement at predetermined regular the intervals in a pressurizing process;
means for comparing the amount of rotational displacement and the amount of linear displacement stored as above with the amount of rotational displacement and the amount of linear displacement sampled anew in a new pressurizing process;
and means for producing a signal notifying a fault when the amount of rotational displacement and the amount of linear displacement sampled anew exceed the amount of rotational displacement and the amount of linear displacement stored respectively by a predetermined tolerance.
power generation means adapted for rotational motion;
conversion means for converting the rotational kinetic energy into the linear kinetic energy;
pressurizing means adapted for linear motion by the linear kinetic energy;
means for detecting the displacement due to a mechanical strain between said pressurizing means and said power generation means as a signal representing a load condition under pressurization, said means for detecting including means for detecting the amount of rotational displacement of a rotary shaft in rotational motion and means for detecting the amount of linear displacement of said pressurizing means;
means for sampling and storing the amount of rotational displacement and the amount of linear displacement at predetermined regular the intervals in a pressurizing process;
means for comparing the amount of rotational displacement and the amount of linear displacement stored as above with the amount of rotational displacement and the amount of linear displacement sampled anew in a new pressurizing process;
and means for producing a signal notifying a fault when the amount of rotational displacement and the amount of linear displacement sampled anew exceed the amount of rotational displacement and the amount of linear displacement stored respectively by a predetermined tolerance.
28. An apparatus according to Claim 27, wherein said means for detecting the amount of rotational displacement includes a rotary pulse encoder, said means for detecting the amount of linear displacement includes a linear pulse encoder, whereby the amount of rotational displacement is represented as a count value of pulses from the rotary pulse encoder, and the timing of sampling at regular time intervals substantially coincides with the timing of the pulses produced from selected one of the two pulse encoders.
29. An apparatus according to Claim 28, wherein the timing of sampling substantially coincides with the timing of pulses produced from said linear pulse encoder.
30. An apparatus according to Claim 29, wherein said storage means stores the number of pulses generated from said rotary pulse encoder between the (N-1)th (N:Integer) sampling operation and the N-th sampling operation, and said comparison means includes means for comparing the number of pulses generated from said rotary pulse encoder between the (N-1)th sampling operation and the N-th sampling operation effected anew in a new pressurizing process with the number of pulses stored.
31. An apparatus according to Claim 28, wherein the timing of sampling substantially coincides with the timing of the pulses produced from the rotary pulse encoder.
32. An apparatus according to Claim 31, wherein said storage means stores the number of pulses generated from said linear pulse encoder between the (N-1)th (N:Integer) sampling operation and the N-th sampling operation, and said comparison means includes means for comparing the number of pulses generated from the linear pulse encoder between the (N-1)th and N-th sampling operations effected anew in a new pressurizing process with the number of pulses stored.
33. An apparatus according to Claim 28, wherein said storage means includes means for storing an average value of the amount of rotational displacement and that of the amount of linear displacement obtained by repeating a predetermined number of pressurizing processes.
34. An apparatus according to Claim 33, wherein said means for selecting a predetermined number of pressurizing processes includes means for selecting the number n (n: Given integer) of a plurality of continuously-conducted pressurizing processes.
35. An apparatus according to Claim 33, wherein said means for selecting a predetermined number of pressurizing processes includes means for selecting a number n (n: Given integer) of pressurizing processes already conducted continuously.
36. An apparatus according to Claim 33, wherein said means for selecting a predetermined number of pressurizing processes includes means adapted for switching between the first number n of a plurality of continuously-conducted pressurizing processes and a given number n (n: Given integer) of pressurizing processes already conducted.
37. A method of abnormal load detection comprising:
the step of detecting a load change of the work and converting the detection into an electrical signal;
the step of sampling the electrical signal converted at selected one of a plurality of pressurizing positions and a plurality of points of pressurizing time;
the step of comparing the sample value with a normal value of the electrical signal corresponding to the sampling point; and the step of deciding on an abnormal load condition when the result of comparison exceeds a predetermined tolerance.
the step of detecting a load change of the work and converting the detection into an electrical signal;
the step of sampling the electrical signal converted at selected one of a plurality of pressurizing positions and a plurality of points of pressurizing time;
the step of comparing the sample value with a normal value of the electrical signal corresponding to the sampling point; and the step of deciding on an abnormal load condition when the result of comparison exceeds a predetermined tolerance.
38. A method according to Claim 37, wherein said step of detecting a load change and converting it into an electrical signal includes the step of detecting the power consumption of a motor.
39. A method according to Claim 37, wherein said step of detecting a load change and converting it into an electrical signal includes the step of detecting the mechanical strain of said pressurizing apparatus.
40. A system according to Claim 38 or 39, wherein said step of converting a load change into an electrical signal includes the steps of converting the electrical signal into a frequency and counting the frequency; and said step of sampling includes the step of sampling the count value of said counter.
41. A method according to Claim 38 or 39, wherein said step of sampling includes the step of A/D conversion of the sampled electrical signal.
42. A method according to Claim 41, wherein said step of comparison includes the step of adding the A/D-converted values and the step of comparing the added value of A/D conversion with said normal value.
43. A method of abnormal load detection for a pressurizing apparatus comprising power generation means adapted for rotational motion, means for converting the rotational kinetic energy into the linear kinetic energy and pressurizing means adapted for linear notion by the linear kinetic energy, said method comprising the steps of counting the number of pulses generated by a pulse encoder for detecting the amount of rotational displacement of a rotary shaft in rotational motion, counting the number of pulses generated by a pulse encoder for detecting the amount of linear displacement of the pressurizing means, and detecting an abnormal load condition from the difference between the count values generated from said two pulse encoders.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22496288 | 1988-09-08 | ||
| JP63-224962 | 1988-09-08 | ||
| JP63-325304 | 1988-12-23 | ||
| JP32530488A JPH02176435A (en) | 1988-09-08 | 1988-12-23 | Apparatus and method for detecting abnormal load in pressure apparatus |
| JP01-54837 | 1989-03-07 | ||
| JP5483789A JPH02235600A (en) | 1989-03-07 | 1989-03-07 | Instrument and method for detecting abnormal load in pressurizing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324423C true CA1324423C (en) | 1993-11-16 |
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ID=27295419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000610074A Expired - Fee Related CA1324423C (en) | 1988-09-08 | 1989-08-31 | Apparatus and method of detecting abnormal load of pressurizing apparatus |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4979401A (en) |
| EP (1) | EP0358405B1 (en) |
| KR (1) | KR900005163A (en) |
| AU (1) | AU621146B2 (en) |
| CA (1) | CA1324423C (en) |
| DE (1) | DE68916883T2 (en) |
| ES (1) | ES2060780T3 (en) |
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|---|---|---|---|---|
| US5450756A (en) * | 1992-11-06 | 1995-09-19 | Toyota Jidosha Kabushiki Kaisha | Device and method for measuring and adjusting pressing load values on a press |
| DE19617105C2 (en) * | 1996-04-19 | 1998-07-02 | Mannesmann Ag | Device for recording the current load on funds, especially hoists |
| KR100302549B1 (en) * | 1997-12-02 | 2001-09-22 | 박종섭 | Phase difference measuring circuit of full electronic exchange network synchronization apparatus |
| US6208159B1 (en) | 1998-03-11 | 2001-03-27 | The Minster Machine Company | Machine press motor load monitor |
| DE69823977T2 (en) * | 1998-03-16 | 2005-05-19 | Yamada Dobby Co. Ltd., Bisai | Control device for the ram of a press |
| US6003441A (en) * | 1999-01-25 | 1999-12-21 | Pmds, L.L.C. | Waste compacting system with system supervisor |
| US6250216B1 (en) | 1999-03-19 | 2001-06-26 | The Minster Machine Company | Press deflection controller and method of controlling press deflection |
| DE10211397C1 (en) * | 2002-03-15 | 2003-12-11 | Schuler Pressen Gmbh & Co | Press operating method uses detected velocity variation of fly-wheel of operating drive for calculation of actual press function value for process parameter correction |
| DE102012023665A1 (en) * | 2012-12-04 | 2014-06-05 | Brankamp Gmbh | Punching device with a sensor and method for transmitting a sensor signal |
| JP6666077B2 (en) * | 2015-04-30 | 2020-03-13 | コマツ産機株式会社 | Press system and control method of press system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3348234A (en) * | 1962-03-20 | 1967-10-17 | Reliance Electric & Eng Co | Production line operation monitor and recorder |
| DE2013272A1 (en) * | 1970-03-20 | 1971-10-07 | Maschinenfabrik Weingarten Ag, 7987 Weingarten | Method and device for monitoring the running area of a machine, in particular a press |
| US3825811A (en) * | 1973-02-26 | 1974-07-23 | Aluminum Co Of America | System and method for monitoring a press load |
| USRE30298E (en) * | 1974-07-22 | 1980-06-03 | Impact sensing detector | |
| US3930248A (en) * | 1974-07-22 | 1975-12-30 | Michael I Keller | Impact sensing detector |
| JPS5728700A (en) * | 1980-07-29 | 1982-02-16 | Aida Eng Ltd | Motion detector |
| JPS5821130A (en) * | 1981-07-30 | 1983-02-07 | Komatsu Ltd | Load measuring device for press machine |
| JPS5862000A (en) * | 1981-10-07 | 1983-04-13 | Riken Keiki Nara Seisakusho:Kk | Method and apparatus for detecting abnormal movement of reciprocating body |
| DD208457A3 (en) * | 1982-01-18 | 1984-05-02 | Otto Hoffmann | CIRCUIT ARRANGEMENT FOR MONITORING SPEED DIFFERENCES ON TOOLING MACHINES, ESPECIALLY PRESSES |
| JPS5922902A (en) * | 1982-07-29 | 1984-02-06 | Daicel Chem Ind Ltd | Suspension polymerization process |
| GB2127973B (en) * | 1982-10-05 | 1986-02-12 | Bl Tech Ltd | Monitoring a power press electrically |
-
1989
- 1989-08-29 AU AU40866/89A patent/AU621146B2/en not_active Ceased
- 1989-08-31 ES ES89308802T patent/ES2060780T3/en not_active Expired - Lifetime
- 1989-08-31 EP EP89308802A patent/EP0358405B1/en not_active Expired - Lifetime
- 1989-08-31 DE DE68916883T patent/DE68916883T2/en not_active Expired - Fee Related
- 1989-08-31 CA CA000610074A patent/CA1324423C/en not_active Expired - Fee Related
- 1989-09-06 US US07/403,475 patent/US4979401A/en not_active Expired - Fee Related
- 1989-09-08 KR KR1019890012982A patent/KR900005163A/en not_active Application Discontinuation
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| KR900005163A (en) | 1990-04-13 |
| AU621146B2 (en) | 1992-03-05 |
| ES2060780T3 (en) | 1994-12-01 |
| DE68916883T2 (en) | 1994-12-08 |
| DE68916883D1 (en) | 1994-08-25 |
| EP0358405A3 (en) | 1991-07-03 |
| AU4086689A (en) | 1990-03-22 |
| EP0358405B1 (en) | 1994-07-20 |
| EP0358405A2 (en) | 1990-03-14 |
| US4979401A (en) | 1990-12-25 |
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