CA2008460A1 - Automatically positionable chair - Google Patents
Automatically positionable chairInfo
- Publication number
- CA2008460A1 CA2008460A1 CA002008460A CA2008460A CA2008460A1 CA 2008460 A1 CA2008460 A1 CA 2008460A1 CA 002008460 A CA002008460 A CA 002008460A CA 2008460 A CA2008460 A CA 2008460A CA 2008460 A1 CA2008460 A1 CA 2008460A1
- Authority
- CA
- Canada
- Prior art keywords
- motor
- chair
- current
- support surface
- microprocessor
- 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.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G15/00—Operating chairs; Dental chairs; Accessories specially adapted therefor, e.g. work stands
- A61G15/02—Chairs with means to adjust position of patient; Controls therefor
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/19—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
- G05B19/40—Open loop systems, e.g. using stepping motor
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/37—Measurements
- G05B2219/37311—Derive speed from current, use of lookup table
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/37—Measurements
- G05B2219/37314—Derive position from speed
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/45—Nc applications
- G05B2219/45022—Auto seat, dentist chair, roll wheel chair
Abstract
Abstract Of The Disclosure A programmable automatic positioning chair for medical application. The chair has moveable support surfaces which are driven by electric motors to preprogrammed positions. Motor speed is determined by measuring the motor current, and the motor speed is integrated by a microprocessor to produce a computed value of surface position. The chair operates "open loop" without any feedback from position sensors.
Description
2~
Z~UTOMATICALI,Y POSITIONABLE CHAIR
sackqround of The Invention This invention relate~ to the field of automatic positioning chairs for medical application. Such chairs are sometimes referred to by the general term "table" and when the word "chair" is used herein, it is intended to include such a "tablen. The invention has particular application to podiatry chairs which may be automatically elevated or tilted and which may have automatically moveable back supports or foot supports.
Prior art chairs of the tvpe with which this invention is concerned use feedback sensors for measuring the position of moveable surfaces and signaling the measured position to a motor controller. Automatic positioning control is achieved by comparing a position command with a measured position to develop an error signal. The position motors are driven until the error signal has been reduced to zero. At this point, the controller knowis that the desired position is achieved.
Prior art chairs of the above described type have al 80 been provided with control units having switches which may be operated to move various support surfaces to desired locations. When the desired locations are achieved, the operator activates a switch directing the control system to store the positions of all moveable surfaces. Thereafter the chair may be returned to the same po3itional configuration by operating the same or another switch.
There has been a need for automatically positionable chairs capable of returning to a programmed po~ition without the use of feedback sensor~. such sensors complicate the design and increase the cost of the chair. It is apparent that such a chair may be operated "open loop"
without position sensor~ by simply measuring the time required to move the chair surfaces to a desired position and treating such movement time as a measurement of position~
However, it is desired to move such chairs to a variety of ~-~
preprogrammed positions under various load conditions which may be encountered during movement with patients of differing weights seated thereon. Drive motors are prone to operate at different speeds under different load conditions. This is especially true for electric motors which are de~igned with the anticipated operating load in mind and which do not have substantial overcapacity. It is impractical to utilize elapsed movement time as a measure of ~urface position when the motor speed change~ with load.
Summarv Of The Invention Thi~ invention provides a programmably positionable chair which may be directed to move to sélectively preprogra~med positions without any use of position feedback.
- Such po~itioning control i8 achieved by providing electric motors for moving the positionable support ~urface~ and mea~uring the motor current during surface movement. It has been found that variable load conditions affect the motor current as well as the motor speed and that there i8 a relationship between motor current and motor speed which is independent of load for a given supply voltage. In accordance with this invention, the relationchip between motor current and motor speed for a supply voltage of `
8~6~ ~
interest is experimentally e~tablished. This relation~hip is programmed into the controller, ~o that motor current measurement~ may be used as an indication of motor speed.
The motor ~peed, so determined, is integrated over the S movement time to establish surface position. The chair support surfaces are driven to computed positions on an open loop basis without any position feedback.
A chair in accordance with thi~ invention may use anywhere from one to four or more electric motors for driving a like number of support surfaces. In a typical application, a podiatry chair in accordance with thi~ invention, may have a programmable back po~ition and a programmable foot support position. Moreover, the seat may rest upon a base which may be automatically elevated to a programmed po~ition and automatically tilted to a programmed tilt angle. A
plurality of programmed position combinations may be established. In a preferred embodiment, the controller utilizes a programmed microprocessox, and the current flows through the electric motors are measured by Hall effect devices.
It is therefore an object of this invention to provide an automatically positionable chair which may be controlled to assume selectively programmed positions without the u~e o~ position feedback and to do 80 irrespective of load conditions.
~ Other and further objects of the invention will be ¦ apparent from the following description, the appended claims and the attached drawings.
' . ' MID 070 P2 - 4 - :
Brief Description Of The Drawinq~ ~
Fig. 1 is a perspective view of a podiatry chair; -Fig. 2 is a ide elevation view of a podiatry chair -in a flat position;
Fig. 3 is a bottom elevation view of a podiatry chair taken along lines 3--3 of Fig. 2;
Fig. 4 is a schematic electric diagram illustrating connections for a hand held program controller;
Figs. 5A - 5C are an electrical ~chematic diagram of a microproces~or connected for open loop control of drive motors for a programmable podiatry chair;
Figs. 6A and 6B are an electrical schematic diagram of circuity for tran~mitting motor current measurements to the microprocessor arrangement illustrated in Figs. SA - SC;
and Fig. 7 is an electrical schematic diagram of connections for a watchdog circuit.
DescriPtion Of The Preferred Embodiments A podiatry chair having programmable positiona in accordance with the present invention is shown in Fig. 1.
The chair 20 includes a base 22 to which a chair frame 24 is mounted. A plurality of upholstered sections 26 are removably mounted to chair frame 24 by hook and loop fabric strips or the like, so that uphol~tered sections 26 may be easily removed for cleaning or repair. The chair frame 24 comprises a back 30 pivotally attached to a seat 32. A foot support 60 is attached to seat 32. The chair model illustrated in Fig. 1 ha~ a powered back, powered tilt, and powered elevation. A slightly different model of podiatry 2008~60 chair, as illustrated in Figs. 2 and 3 may also have a powered foot support.
Referring now to Fig~. 2 and 3, chair 20 is provided with four electric drive motors: including a base motor 61, a back motor 66, a tilt motor 67 and a foot motor 62. Motors 61, 66, 67 and 62 are reversibly operated to power a back actuator 34, a tilt actuator 36, a base actuator 38, and a foot actuator 33 respectively. Controls for the ~
drive motors comprise a series of switches mounted in a hand ~-control unit 40 detachably mounted on the side of foot support 60. Hand control unit 40 also includes switches for programming the automatic control, as hereinafter described.
Actuators 34 and 36 include a screw shaft and gearing means or the like for enabling the re~pective motors lS to rotate their shafts. A nut is mounted on each shaft for converting the rotary motion of the shaft into linear motion of actuator arms 68 and 69. Actuator arms 68 and 69 in turn position back 30 and tilt seat 32. Foot actuator 33 operates in a similar manner for angular positioning of foot support 60.
Actuator 3B i8 mounted in base 22 and is secured to upper plate 86. Ba~e actuator 38 converts the rotary motion of base motor 61 into linear motion for operation of a scissors mechanism 88, as illustrated in Fig. 2.
The control system for the chair is illustrated in Figs. 4, 5A-SC, 6A, 6B and 7. The heart of the control system is a microproces~or 100 which i8 illustrated in Fig.
5B a~ having pin connections corresponding to those of a microprocessor sold by Zilog, Inc. under the trademark ~ C~
~ 2~)0E~
~:
:
Super8. Cloc~ pulses for microprocessor 100 are provided by a 12 MH. crystal.
Pin numbers 40-47 of microprocessor 100 are connected to a cable 203, which in turn is connected to ~olenoid operated switches 151 - 158. Microprocessor 100 selectively closes switches 151 - 158 ~Fig. 5c) for powering and directionally controlling base motor 61, back ~otor 66, tilt motor 67, and foot motor 62. Closure of switch 151 causes rotation of base motor 61 in a direction which causes upward move~ent of base 22. Base 22 is driven downwardly by opening swit~h 151 and closing switch 152. Switches 153 and 154 similarly cause upward and downward motion of back 30, while switches 155 and 156 cause upward and downward tilting of seat 32, and switcheY 157, 158 cause downward rotation of foot support 60.
Electrical current for motor~ 61, 66, 67 and 62 flows through choke coils 161, 166, 167 and 162 respectively.
Current flows through these choke coils are sensed by Hall effect devices 121, 126, 127 and 122 respectively ~Fig.
SA). Output signalis from the Hall effect devices are applied to operational amplifiers 221 - 224 which detect overcurrent conditions of the type which may occur when a foreign ob~ect interferes with motion of the chair. Output signals from operational amplifiers from 221- 224 are applied to pin numbers 24 - 27 respectively of microprocessor 100 to stop the overcurrent condition by opening the appropriate ones of switches 151 - 158.
Hand control 40 is connected to microprocessor 100 by means of lines 201, 202. The connection of those lines into hand control unit 40 i8 illustrated in Fig. 4. ~nit 40 2~08~æ~
ha~ fifteen switches 131 - 137 and 141 - 148, which are ;~
sequentially tested by 8-bit parallel to erial converters 109, 110. Microprocessor 100 transmit~ a sequence of clock pulses on line 201 to integrated circuit~ 109, 110 which return a code on line 202 identifying the state of each of the switches in hand control unit 40. The functions of these switches are identified in Table I.
As indicated by Table I, an operator may move foot support surface 60 in the upward direction by closing switch 147. Thereafter, upward movement may be interrupted by activating th~ stop switch 135. The operator may ~imilarly operate switches 142 - 148 in combination with stop switch 135 to achieve any desired relative positions of the moveable chair surface~. Once a desired positioned combination has been achieved, a calculated position set is programmed into the system by actuating the "Program" switch 134 and any one of the our positions select switches 131, 133, 136, 137. ;~
The latter four switches enable a podiatrist to program up to four position combinations into the control system. These four position combinations may be selected to meet his specific professional needs. The chair may be directed to return automatically to any of these positioned combinations by activating the associated one of switches 131, 133, 136 or 137. An "Auto Return" switch 132 is provided for commanding a return to the home position.
It is a feature of this invention that the chair may be controlled automatically to move to selectively programmed positions without using any position sensing transducers. This is accomplished by digitizing the analog output signals from Hall effect devices 121, 126, 127 and 122 `~
20C~8~
~, and using these digitized outputs to solve a position control algorithm. The algorithm as hereinafter described, associates motor cu~rent with speed and integrates the speed over time to establish a computed position.
Digitizing of the analog output signals from the Hall effect devices is performed by analog-to-digital converter 106 ~Fig. 6A). However, prior to digitizing, the Hall effect signals are processed by peak amplifieri 225 -228. These peak amplifiers are connected to one-microfarad capacitors 229 - 232 respectively for providing output signals which represent the average peak currents through choke coils 161, 166, 167 and 162. These average peak current signals are applied to lines 233 - 236 for application to the input terminals of A/D converter 106.
lS A/D converter 106 produces digitized equivalents of the average peak choke coil currents on lines 240 - 247 for application to pin numbers 10 - 17 of microprocessor 100.
Microprocessor 100 also receives programming codes from integrated circuit 102 which is a 16K by 8-bit EPROM.
EPROM 102 operates under control of an address decode latch 101. The computing circuitry also includes an address chip select decoder 103 for selection of EPROM 102 and another address chip select decoder 104 for gelection of a watchdog circuit comprising a clock divider 105 ~Fig. 7). The watchdog circuit generates a microprocessor reset signal, if it doesn't receive a periodic toggle signal from integrated circuit 104. This aisables the motorY in the event of a logic error or a failure of memory. However, if a problem is caused by a "glitch~ induced by an external cau~e, the system will resume operating automatically after the reset.
.' .
MID 070 P2 - 9 ~
It i~ another feature of the position control system that programmed position control information may be stored for up to 48 hours. Such storage is accomplished -through an 8K x 8 RAM 107 connected by a lead line 250 to a large capacitor 251. Capacitor 251 may have a capacitance of about 1 farad which may store sufficient charge to enable the above-noted data retention by RAM 107. Thus an operator may program the chair and then shut down overnight without losing the program data. Positional data is supplied by microprocessor 100 to RAM 107 via address/data bus lineY 240 - 247. Address information (low order bit~) is supplied by addres~/data bus lines 240 - 247 via address latch 108 and by ~i address bus lines 260 - 264 (high order bits~.
As noted above, this invention permits the chair surface~ to be driven to preprogrammed positions by solving algorithms which relate measured motor currents to motor speeds. It i~ important to know the motor speed, because variations in the weight of the patient who is seated on the chair affect the motor speed and hence the time required for the control surface to reach a preprogrammed position.
Knowing the speed of the motor, it is possible to integrate this speed over the movement time to obtain a calculated position. However, it is not necessary to know the actual position, as calculation of an appropriately repeatable position parameter is sufficient. If such a position parameter is calculated during a programming run the corresponding actual position may be achieved during a working run by operating the motors and repeating the calculations until the same value of the position parameter ha~ been calculated.
.
~0~8~0 ` .
The algorithm relating motor ~peed to motor current will vary with ~otor design details but can be readily established in an experimental procedure by applying the design working voltage to the motor and operating the motor against a continuou~ly varying load. A~ the load varies the supply current and shaft angular velocity are ximultaneou~ly measured and recorded. A plot of shaft angular velocity against current establishes the algorithm. The algorithm may be expressed in equation form by conventional curve fitting.
As an alternative the algorithm may be simply reduced to a tabular form and stored in memory. However, the tabular form is avoided where possible, because it uses up large chunks of ;~
memory.
It has been found that for ~any motors the algorithm has a fairly linear form over the current range of interest, 80 that motor speed can be derived to a fair degree of accuracy by the expression:
S = -Kl C + Ki, I
where: S is the motor ~peed C is the motor current K~ are constants to be experimentally determined It has also been found that the above expres~ion is not accurate for the conditions which obtain during ~tarting and stopping. However, it i~ generally satisfactory to assume a con~tant average speed ~independent of load) during ~~ 1 T,~
Z008Ds~
,.
these time periods. That speed, again, is determined experimentally.
In general the motor pocition i8 given by the equation:
X = s dt = - K1 C dt + K2T
where T is the total elapsed time.
If the starting time period i8 Gl and the stop period is G2, and the motor has an average speed SA dl1ring :~
these periods, then to a fairly good approximation:
X = SA ~G1 I G~) + X~ ~T - Gl - G2) - Kl C dt For a microprocessor computing at regularly timed intervals t X = SA ~Gl ~ G,) + K~ t - KlC t where the summations are taken over the time interval from G
lS to T-G~.
In operation during a working run the microproces~or begins computing at the instant of motor start , ; by calculating ~or looking up in memory) the term SA ~G~ t ' G~) and placing this value in a position register. ~t thereafter counts time intervals until t = Gl which is the known end of the motor start-up phase. Then the microprocessor calculates (K~ - RlC) t for each computing 200a~;o cycle and adds thi~ into the po~ition regi~ter. This is continued until the position register holds a predetermined target value. The time then is tby definition~ T-G~, and the drive motor is switched off automatically. For a programming run the operator switches the drive motor off manually when a desired position has been reached, and the value then in the position register is stored to become a new target value. In practice, since only a position parameter expres~ing a relative distance i~ required, Gl and Gz are expressed in terms of the number of elapsed computing cycles, and t is set equal to 1Ø
A routine implementing the above technique in SUPER 8 assembly language for foot motor 62 is listed in Table II.
In order to understand Table II it may be observed that the above-noted term Kz - KlC may be rewritten a~
K1 ~C - K~/K ). The program for the foot includes routines for running the foot motor up and running the foot motor down. Within these routines there are subroutines covering the two alternative conditions wherein the me~sured current i8 greater than or less than the no load current.
Referring now to program line noB. 721 - 730 for foot motor up and measured current greater than no load current and making the substitutions:
C = AV FT
K2/K1 = UP NL CUR FT
K = UP NL FAC FT
r;
200846(~) It may be seen that the computer performs a series of steps which calculate the term K~-K~C. The calculated value is added into a register known as ADD FT. Other program listings, not shown, include similar routines for S simultaneously controlling the position of motor~ Gl, G6 and G7.
It will be appreciated that frictional losses, motor slippage and cumulative computing errors will cause error# in the calculated motor position which will grow with the passage of time. Such error~ are small enough to be unobjectionable in an automatically positionable chair. In any event they may be removed by periodically returning the chair to the home position. When thi~ is done the position registers are all automatically zeroed.
While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention 1 which i- defined in the appended claim~.
I
~' 2~)08~
, ..
-l3~ -MID 070 P2 - ~U~ -TABLE I
:
Switch Functions For Hand Control Switch No. Function ~:
131 Select Position 3 132 Auto Return :
133 Select Position 1 134 Program 135 Stop 136 Select Position 2 137 Select Position 4 141 Base ~p 142 Base Down 143 Back Up 144 Back Down ~:~
145 Tilt Up ~:
`; :
146 Tilt Down 147 Foot Up :~
148 Foot Down .
,~
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taQe I~ID~ PODlaTRY T1111LE ~ 17 F~R_FT. aRC
2500 P..D. Super ~ l~acro P6se-bler - Version s.oe.
Input Filena~e: c;\Z511~-id~ark~src\for ft.src Output Filenaee s os\2500ad\~id~a~k\obi\foe ft.obJ
Listing Has Bee~ ted 6~2 .list on 603 .title ~IIO~RK PODlP~TRY TP~ 16, ~17, 6U .subtitle FOR_FT.SllC
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w6 .~OI~aL FOR_~
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6~9 EF03 FF FO~ FTs NP ;TEST ONY~ IlEPUlCE IIITH ~ ~RFtURN~ ~H :::
610 EFU 70 D6 ~I RPO s 611 EF~6 7a D7 PUSH RPI jSaVE RE61STER PIONTER ~Q
613 EF08 31 oe SRW ~OOH ;PIONT TO TEIIP ~IORKIN6 REI; `:
614 EFOa 3169 SRP1 ~H ;PlaNT TO Tll XXXX REB
61~ s `:~
617 ; I I I I I l :~
661~8 ; CNr Xll INDEX XX ~DJ XX
62~ ' ; ~
622 5TEST FOR T~E STOP EDGE
62~ ffOC 76 61 C3 TH ~oSK,~llOOODOa9 ;TEST fOR THE LoCK Of ~ T_f~E
,625 EfOf 6D FO 2~ JP 2,SIOP_fT ;f~E SETEC~ED, RUN STOP
626~ 1 627 IFORHULRS fOR RUN THE fOOT IN TK C04N DIRECTION
629 t 629 EF12 76 61 ~0 fT D~N fOLs T~ HRSN~102eOOOQB ;TEST fOR FODT DO~N
636 f~F15 6D EF 9E IP Z,fT,UP,fOL ;NOT RLN~ NEXT 31T
632 EF16 ~6 3C 00 U IN3EX_FT,1a0QH ;CYECK fDR SIRRTIN6 fDRO~ULR
633 f~FlB 6~ f~F ZD JP EQ,ST_UP_~UN FT ;RUN STW DOUN FORDPULa 63~ EflE ~6 3C Ol CP INDEX_Ft,~DOlH ;CHECX FOR RUNNIN6 fORDNULa 635 f~F2l 6D EF 3B JP E4 STRRT_DHN fT ;STMT RUNNIN6 DOUN FORDqULR
636 f~F2~ ~6 3C oe cP I ~ X_FT,1402H ;CKCN fOR RUNNIN6 fORC~ULR
637 f~F2? 6D fF æ JP ESlRUN_D~N_FT ;STMT RUNNIN6 Di~N fORO~ULR
638 Ef2a 8D ff 9E JP FT_UP_fOL jDELAY OR DOES NOT NED TO DE RUN
6U EFZD E6 3~ 20 SET UP D~N FTt LD CNT_fT,~RUN DELaY ;DELAY EET~EEN STaRT oND RUN
6~1 f3F30 a7 71 U Fg ~DE TEXPR7_R7,D~N_ST_CT_FT ;RUN RORYIII~ DFLaY FDR FT_CNT
6~2 fF3~ 79 4~ LD ~DJ_FT,TE~PR7 R7 j~OVE aDJ_FT
6 U EF36 20 3C INC INDEX_FT ;PIONT TO S~ORT
6U EF33 eD FO 2D JP CLRR ;DONE
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TABLE I I
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~ID~ARK PODI~TRY TaELE ~16, ~17, il~
FOR_FT. SRC
6~6 EF3D a6 3~ 00 STaRT D~IN_FT: CP CNT F~,#100H ;aECK IF STQRT STILL NEDS aDJUSTIN6 6~7 Ef3E El~ 05 JR Nl,ST~RT W~ P~J ;~DJUS~IT STILL IEDE
6~3 EF43 2a 3C INC INDE~ Ft ;PIONT TO RUN
6~9 EF~2 ID F0 2D JP U~ ;D0~E
6S0 EF/~5 P6 U 00 STaRT_D~N_aDJ: CP aDJ_FT,~OOH ;DEC QNC EVERY 2QBS LNTIL IERO
651 EF~B 6D FO 2D JP l,aEaR ;D0K
652 EF48 oa 4~ DEC ~DJ ~ DJUST -I PER 21bS
653 EF~D 60 66 DEC~ l F00T ;STaRT C0tlPEl~T10N
65~ EFU 8D F0 2D JP CLEaR ;D0IE
6S6 EF52 R7 51 30 F9 RUN_DUN FT: LDE TE~PR5 ~5,UP_NL_CUR_fT ;~DNE NO L0RD CURRENT TO RE6 657 EF56 M 05 1~ CP av FT,T~PR5 656 fFS9 P~ 07 JR 6T,aV_6T_N._DUN ;COIIP FOR aVE~6E 611ERtER THRN ND_LOFID
659 EfSB IB 23 JR LT,~V LT_N_~N jCONP FOR ~ERP~6E LE$ TH13N ND_LOP~
660 EFSD 60 6B DECII Tl~_FOOT ;fQUaL, NO CO~IP
661 B5F ~D FO 2D JP 1~1 ;DO~E
~63 Ef62 E~ 14 06 ~V_6T_N. D~l: LD TEI~P~6,RV_Ft ;SaVE COPY OF ~V_FT
66~ EF65 2~ OS 06 SUI~ TEl~PR6,TE~IPRS ;OET ~ DIFFERENOE ~VERP6E TO NO_LOPD
665 ff69 P~7 71 2I f9 LDE tfJlPR7 R7,WN_tL_FPC_fT ;Et W_FaCTOR_FT ~: :
666 Ef6C U 07 06 l~lT TE~IPR6,TEI~PR7 ;~DJUST I~ITH FRCTDR I~ILTI IN
667 EF6F 96 FF 06 DIV TQlPR6,~0fFlt ; .: :
66~ EF72 24 07 U SUB ADD Ft,TE~lPR7 ;P~DD PDJUST~Nt FP~TOR INTO ~N COINT ~ :
669 ff75 36 69 00 SBC TH FOOtR9,~OOOH ;RIPPLE ~RRY THROU6H
670 EF7B 36 6B 00 S~C T~l FGOTR8,~0H ;RIPPLE C~RRY THRal~H
671 EF7a 00 66 OEW T~l FWt 672 EF7D ~D F3 2D JP CLE~R . ;DONE ~
673 ~ :
67~ EF80 E~ 1~ 06 RV Lt NL D'RN: LD TE~PR6,RV FT ;SIWE MPY DF RV_FT
675 EF83 U 06 05 S~9 TEllPRfi,TEtlPR6 ;6ET THE DIFFERB~CE ~ERROE TO ND_LGqD
676 EFB6 R7 71 21 F9 LDE tEHPR7 R7,D~ N F~l: FT ;6ET UP_FPCTM_FT
677 EFBa U S7 06 HULT TEI~PR6,TEIIPR7 ;ADJIIST I~ITH FP~TOR MllTI IN
678 EF6D g6 FF 06 DIV TE~IPR6,~0FFH
679 EF90 Oi 07 U ADD ADD FT,TE~IPR7 ;RDD PWUST~NT FRCTOR INtO RLN COUNT
6BO EF93 16 69 00 aDC Tl~ FOOTR9,N~OOH ;RIPPLE ~qRRY THRDU6H
~I EF96 16 6B 00 aDC THjGoTR9,-000H ;RIPPLE CaRRY THROIIGH
6B2 EF99 20 6B DEC~I Ttl FDDT
6B3 EF9D 6D FO 2D JP a~R ;DON~
685 ~FDRIth~ FGR RLN THE FODT IN T~E W DIRECTII~N
6~6 6B7 EF9E 76 61 ~0 FT UP FQs Tll I~Sll,~01600000B ;TEST FOR FGIDT W
6~ EFal 6D F9 2D JP l,CLE~R ;NDT RUI, NEXT BIT
66g 69~ EFR~ R6 3C OO CP lNDEX FT,tOOOH ;CHECK FOR SToRTlNB FORO~ULa 691 EFa7 6D EF ~9 JP EQ,SET UP W FT ;RUN SETUP UP FOROPU4R
692 ffaa a6 3C Ol CP INDEX FT,taOI~ ;CHECK FOR RUNNIN6 FOROtULa 693 EFRD 0 EF C7 JP EQ,STaRT UP FT ;STRRT RUNNIN6 UP FOROPULR
69~ EF90 R6 3C oe cP INDEX FT,4aqeH ;CHECN FOR RUNNIN6 FORO~ULR
695 EfE3 6D EF DE JP EQ,RUN_UP FT ;STaRT RUNNIN6 UP FORO~ULR
696 EfE6 ~D FO 2D JP CLEOR ;DEL~Y OR DCES NOT NEED TO EE RUN
6n 690 EFS9 E6 38 2a ST UP UP_FT: LD W FT,tRUN DEUY jDELRH EET~EEN ST~RT oND RUN
699 EFEC a7 71 50 F9 LDE TE~PR7 R7, W ST CT FT ~RUN FOR~UL~, DEL~Y FOR FT W
70a EFC8 79 4~ LD PDJ_FT,TE~PR7_R7 ;POUE RDJ_FT
Pdge 3 ~ID~RK PODI~TRY T~aLE ~ 17, ~1 F~R_Ft. SRC
701 EFC2 20 3C INC I~X FT ;PIONT TO ST~RT
7æ EFU aD FO 2D IP CLEP~
7~ EFC7 ~16 3S 0~ STaRT~ Ft: CP CtlT_Ft,~OH ;CHEa~ IF STaRt StllL \~EEDS P~JUStlN~
705 EFbq E~ C5 JR NZ,STaRl_UP_~DS ;~DJUST~IENT STILL I~DED0 706 EFCC ~0 3C INC INDEX_FT ;PlONr TO ~N
7~7 EFOE ~D FO 2D JP CLEQR ;DO~E
70~ I~Dl P6 ~ 00 ST~RT UP NDJ: CP ~DJ FT,NOOII ;DEC ON~E ~ERY 2a~s UN~IL ZERO ::
~Og EFD~ 6D FO 2D JP Z,CLEaR ;DOilE
710 EFD7 00 4~ DEC ~DJ FT ;~WUST -I PER 2bS ::
711 EF`D9 80 6~ I T~l_FQOT ;ST~RT COlWlSAtlON712 EFDa aD f0 2D JP CLEPR ;DONE
71~ EFDE ~7 51 30 F9 RUN_UP_Ft: LDE tf~lPR5_R5,W_llL_OUR_FT ;~IDVE NO LCP~ CURRENT TO ~B `:
715 EFE2 M ~5 IJ~ CP ~V FT,TE~Pa5 j ~ -716 EFE5 ~ 07 JR 6T,M/_6t_1~_UP ;COI~P FOR ~VERR6E 6RE~tER rNaN NO LoaD
717 EFE7 1~ 23 J~ LT,~V_LT_NL_UP ;Cal~P F~R M~Ra6E LESS THIW NO_LOAD : `
716 ffE9 a0 68 I~ tl~_FODT ;EWL, NO C~
719 EFEII ~D FO 2D JP DEQR ;DOIE
721 EFEE E~ V 6T N_UP: LD Ta~PR6,aN_FT ;SaVE COPY ff RJ_fT
722 ~fFl 2~ 05 06 SUII TE~PR6,TE~PR5 ;6t TK DlfFERENCE ~IE~6E TO ~JD_LOPD
723 EFF~ P17 71 31 F9 LDE tE~lPR7 R7,W_N_FaC_Ft ;6ET UP FaCTOR_FT
72~ EFF2 U 07 06 ~lT TEIIPR6,TE~PR7 ;P~JUST ~IITH F~CTO~ IULTI IN
72S EFF6 X FF 06 DIV TE~IP116,~0FFH ;
726 EFFE 2~ 07 U SUB ~DD FT,TEIIPR7 ;~ JUSTl~NT FaCTOR INTO RUN COINT
727 FOOI 36 6g 00 SEIC T~l_FODTR9,~H ;RIPPLE C4MY THRW6H
720 FOO~ 3S 6B 00 SDC T~ FMTRB,1000H ;RIPPLE C~RRY THIDUGH
729 F007 ~0 6B INCll T~l fODT
730 F~llg ~D FO 2D JP Cl~R ;WNE
731 2 .
732 FOOC E4 14 06 ~V LT_NL UPI LD IE~lPR6,a'l1 FT ;SlWE COPY Of ~U FT
733 FOOF 2~ 06 05 SU~ TfllPR5,TEllPR6 ;6ET THE DIFFER~ICE ~tlER~6E TO ND_LOPD
73~ Fel2 ~7 71 31 F9 LDE TE~lPR7_R7,UP_NL_F~_fT ;6ET W_FPCTOR!FT
73S F016 U 07 06 IIULT TEDP~6,Tf~lPR7 ;~DJUST I~ITH FaOTOR I~ULTI IN
.736 FOI9 96 FF 06 DIV Tf~PR6,10FfH J
737 tOIC 0~ 07 U PDD PDD_FT,~IPR7 ;~DD PDJUST~T FaCTOR INTO RUI COlNT
7311 FOlF 16 69 00 P~C T~l FOOT~9,~OOH ;RIPPLE C~RRY T~H
739 fO22 16 60 00 aDC Tll FOOTRô~OOOH ;RIPPLE CMRY TIWU6H
1U t 2S P/O 69 INC~I Tll FOOT
7~1 tO27 ~ FO 2D JP CLEIIR ;DONE
7~2 J
7U ;~IOTOR DO~E, RES~T INDEX PlaNTER
7~ ~ ~7U F02R E6 3C 00 STOP_FT2 . LD INDEX_fT,lOOOH ;IIDTOR STOPPED, RESET INDEX TD 2ERO
7~6 i 7~7 ;C~R TO EXIT
7~ J
7~9 F02D 59 D7 CLE~Rt POP RPI
750 tO2f 50 D6 POP RP~ ;RfPLaC~ ~61ST~R PINTER
751 F031 RF RET ;WNE
7æ J
Line5 P~ bled t 752 ~s5nbly ~rors: O
Z~UTOMATICALI,Y POSITIONABLE CHAIR
sackqround of The Invention This invention relate~ to the field of automatic positioning chairs for medical application. Such chairs are sometimes referred to by the general term "table" and when the word "chair" is used herein, it is intended to include such a "tablen. The invention has particular application to podiatry chairs which may be automatically elevated or tilted and which may have automatically moveable back supports or foot supports.
Prior art chairs of the tvpe with which this invention is concerned use feedback sensors for measuring the position of moveable surfaces and signaling the measured position to a motor controller. Automatic positioning control is achieved by comparing a position command with a measured position to develop an error signal. The position motors are driven until the error signal has been reduced to zero. At this point, the controller knowis that the desired position is achieved.
Prior art chairs of the above described type have al 80 been provided with control units having switches which may be operated to move various support surfaces to desired locations. When the desired locations are achieved, the operator activates a switch directing the control system to store the positions of all moveable surfaces. Thereafter the chair may be returned to the same po3itional configuration by operating the same or another switch.
There has been a need for automatically positionable chairs capable of returning to a programmed po~ition without the use of feedback sensor~. such sensors complicate the design and increase the cost of the chair. It is apparent that such a chair may be operated "open loop"
without position sensor~ by simply measuring the time required to move the chair surfaces to a desired position and treating such movement time as a measurement of position~
However, it is desired to move such chairs to a variety of ~-~
preprogrammed positions under various load conditions which may be encountered during movement with patients of differing weights seated thereon. Drive motors are prone to operate at different speeds under different load conditions. This is especially true for electric motors which are de~igned with the anticipated operating load in mind and which do not have substantial overcapacity. It is impractical to utilize elapsed movement time as a measure of ~urface position when the motor speed change~ with load.
Summarv Of The Invention Thi~ invention provides a programmably positionable chair which may be directed to move to sélectively preprogra~med positions without any use of position feedback.
- Such po~itioning control i8 achieved by providing electric motors for moving the positionable support ~urface~ and mea~uring the motor current during surface movement. It has been found that variable load conditions affect the motor current as well as the motor speed and that there i8 a relationship between motor current and motor speed which is independent of load for a given supply voltage. In accordance with this invention, the relationchip between motor current and motor speed for a supply voltage of `
8~6~ ~
interest is experimentally e~tablished. This relation~hip is programmed into the controller, ~o that motor current measurement~ may be used as an indication of motor speed.
The motor ~peed, so determined, is integrated over the S movement time to establish surface position. The chair support surfaces are driven to computed positions on an open loop basis without any position feedback.
A chair in accordance with thi~ invention may use anywhere from one to four or more electric motors for driving a like number of support surfaces. In a typical application, a podiatry chair in accordance with thi~ invention, may have a programmable back po~ition and a programmable foot support position. Moreover, the seat may rest upon a base which may be automatically elevated to a programmed po~ition and automatically tilted to a programmed tilt angle. A
plurality of programmed position combinations may be established. In a preferred embodiment, the controller utilizes a programmed microprocessox, and the current flows through the electric motors are measured by Hall effect devices.
It is therefore an object of this invention to provide an automatically positionable chair which may be controlled to assume selectively programmed positions without the u~e o~ position feedback and to do 80 irrespective of load conditions.
~ Other and further objects of the invention will be ¦ apparent from the following description, the appended claims and the attached drawings.
' . ' MID 070 P2 - 4 - :
Brief Description Of The Drawinq~ ~
Fig. 1 is a perspective view of a podiatry chair; -Fig. 2 is a ide elevation view of a podiatry chair -in a flat position;
Fig. 3 is a bottom elevation view of a podiatry chair taken along lines 3--3 of Fig. 2;
Fig. 4 is a schematic electric diagram illustrating connections for a hand held program controller;
Figs. 5A - 5C are an electrical ~chematic diagram of a microproces~or connected for open loop control of drive motors for a programmable podiatry chair;
Figs. 6A and 6B are an electrical schematic diagram of circuity for tran~mitting motor current measurements to the microprocessor arrangement illustrated in Figs. SA - SC;
and Fig. 7 is an electrical schematic diagram of connections for a watchdog circuit.
DescriPtion Of The Preferred Embodiments A podiatry chair having programmable positiona in accordance with the present invention is shown in Fig. 1.
The chair 20 includes a base 22 to which a chair frame 24 is mounted. A plurality of upholstered sections 26 are removably mounted to chair frame 24 by hook and loop fabric strips or the like, so that uphol~tered sections 26 may be easily removed for cleaning or repair. The chair frame 24 comprises a back 30 pivotally attached to a seat 32. A foot support 60 is attached to seat 32. The chair model illustrated in Fig. 1 ha~ a powered back, powered tilt, and powered elevation. A slightly different model of podiatry 2008~60 chair, as illustrated in Figs. 2 and 3 may also have a powered foot support.
Referring now to Fig~. 2 and 3, chair 20 is provided with four electric drive motors: including a base motor 61, a back motor 66, a tilt motor 67 and a foot motor 62. Motors 61, 66, 67 and 62 are reversibly operated to power a back actuator 34, a tilt actuator 36, a base actuator 38, and a foot actuator 33 respectively. Controls for the ~
drive motors comprise a series of switches mounted in a hand ~-control unit 40 detachably mounted on the side of foot support 60. Hand control unit 40 also includes switches for programming the automatic control, as hereinafter described.
Actuators 34 and 36 include a screw shaft and gearing means or the like for enabling the re~pective motors lS to rotate their shafts. A nut is mounted on each shaft for converting the rotary motion of the shaft into linear motion of actuator arms 68 and 69. Actuator arms 68 and 69 in turn position back 30 and tilt seat 32. Foot actuator 33 operates in a similar manner for angular positioning of foot support 60.
Actuator 3B i8 mounted in base 22 and is secured to upper plate 86. Ba~e actuator 38 converts the rotary motion of base motor 61 into linear motion for operation of a scissors mechanism 88, as illustrated in Fig. 2.
The control system for the chair is illustrated in Figs. 4, 5A-SC, 6A, 6B and 7. The heart of the control system is a microproces~or 100 which i8 illustrated in Fig.
5B a~ having pin connections corresponding to those of a microprocessor sold by Zilog, Inc. under the trademark ~ C~
~ 2~)0E~
~:
:
Super8. Cloc~ pulses for microprocessor 100 are provided by a 12 MH. crystal.
Pin numbers 40-47 of microprocessor 100 are connected to a cable 203, which in turn is connected to ~olenoid operated switches 151 - 158. Microprocessor 100 selectively closes switches 151 - 158 ~Fig. 5c) for powering and directionally controlling base motor 61, back ~otor 66, tilt motor 67, and foot motor 62. Closure of switch 151 causes rotation of base motor 61 in a direction which causes upward move~ent of base 22. Base 22 is driven downwardly by opening swit~h 151 and closing switch 152. Switches 153 and 154 similarly cause upward and downward motion of back 30, while switches 155 and 156 cause upward and downward tilting of seat 32, and switcheY 157, 158 cause downward rotation of foot support 60.
Electrical current for motor~ 61, 66, 67 and 62 flows through choke coils 161, 166, 167 and 162 respectively.
Current flows through these choke coils are sensed by Hall effect devices 121, 126, 127 and 122 respectively ~Fig.
SA). Output signalis from the Hall effect devices are applied to operational amplifiers 221 - 224 which detect overcurrent conditions of the type which may occur when a foreign ob~ect interferes with motion of the chair. Output signals from operational amplifiers from 221- 224 are applied to pin numbers 24 - 27 respectively of microprocessor 100 to stop the overcurrent condition by opening the appropriate ones of switches 151 - 158.
Hand control 40 is connected to microprocessor 100 by means of lines 201, 202. The connection of those lines into hand control unit 40 i8 illustrated in Fig. 4. ~nit 40 2~08~æ~
ha~ fifteen switches 131 - 137 and 141 - 148, which are ;~
sequentially tested by 8-bit parallel to erial converters 109, 110. Microprocessor 100 transmit~ a sequence of clock pulses on line 201 to integrated circuit~ 109, 110 which return a code on line 202 identifying the state of each of the switches in hand control unit 40. The functions of these switches are identified in Table I.
As indicated by Table I, an operator may move foot support surface 60 in the upward direction by closing switch 147. Thereafter, upward movement may be interrupted by activating th~ stop switch 135. The operator may ~imilarly operate switches 142 - 148 in combination with stop switch 135 to achieve any desired relative positions of the moveable chair surface~. Once a desired positioned combination has been achieved, a calculated position set is programmed into the system by actuating the "Program" switch 134 and any one of the our positions select switches 131, 133, 136, 137. ;~
The latter four switches enable a podiatrist to program up to four position combinations into the control system. These four position combinations may be selected to meet his specific professional needs. The chair may be directed to return automatically to any of these positioned combinations by activating the associated one of switches 131, 133, 136 or 137. An "Auto Return" switch 132 is provided for commanding a return to the home position.
It is a feature of this invention that the chair may be controlled automatically to move to selectively programmed positions without using any position sensing transducers. This is accomplished by digitizing the analog output signals from Hall effect devices 121, 126, 127 and 122 `~
20C~8~
~, and using these digitized outputs to solve a position control algorithm. The algorithm as hereinafter described, associates motor cu~rent with speed and integrates the speed over time to establish a computed position.
Digitizing of the analog output signals from the Hall effect devices is performed by analog-to-digital converter 106 ~Fig. 6A). However, prior to digitizing, the Hall effect signals are processed by peak amplifieri 225 -228. These peak amplifiers are connected to one-microfarad capacitors 229 - 232 respectively for providing output signals which represent the average peak currents through choke coils 161, 166, 167 and 162. These average peak current signals are applied to lines 233 - 236 for application to the input terminals of A/D converter 106.
lS A/D converter 106 produces digitized equivalents of the average peak choke coil currents on lines 240 - 247 for application to pin numbers 10 - 17 of microprocessor 100.
Microprocessor 100 also receives programming codes from integrated circuit 102 which is a 16K by 8-bit EPROM.
EPROM 102 operates under control of an address decode latch 101. The computing circuitry also includes an address chip select decoder 103 for selection of EPROM 102 and another address chip select decoder 104 for gelection of a watchdog circuit comprising a clock divider 105 ~Fig. 7). The watchdog circuit generates a microprocessor reset signal, if it doesn't receive a periodic toggle signal from integrated circuit 104. This aisables the motorY in the event of a logic error or a failure of memory. However, if a problem is caused by a "glitch~ induced by an external cau~e, the system will resume operating automatically after the reset.
.' .
MID 070 P2 - 9 ~
It i~ another feature of the position control system that programmed position control information may be stored for up to 48 hours. Such storage is accomplished -through an 8K x 8 RAM 107 connected by a lead line 250 to a large capacitor 251. Capacitor 251 may have a capacitance of about 1 farad which may store sufficient charge to enable the above-noted data retention by RAM 107. Thus an operator may program the chair and then shut down overnight without losing the program data. Positional data is supplied by microprocessor 100 to RAM 107 via address/data bus lineY 240 - 247. Address information (low order bit~) is supplied by addres~/data bus lines 240 - 247 via address latch 108 and by ~i address bus lines 260 - 264 (high order bits~.
As noted above, this invention permits the chair surface~ to be driven to preprogrammed positions by solving algorithms which relate measured motor currents to motor speeds. It i~ important to know the motor speed, because variations in the weight of the patient who is seated on the chair affect the motor speed and hence the time required for the control surface to reach a preprogrammed position.
Knowing the speed of the motor, it is possible to integrate this speed over the movement time to obtain a calculated position. However, it is not necessary to know the actual position, as calculation of an appropriately repeatable position parameter is sufficient. If such a position parameter is calculated during a programming run the corresponding actual position may be achieved during a working run by operating the motors and repeating the calculations until the same value of the position parameter ha~ been calculated.
.
~0~8~0 ` .
The algorithm relating motor ~peed to motor current will vary with ~otor design details but can be readily established in an experimental procedure by applying the design working voltage to the motor and operating the motor against a continuou~ly varying load. A~ the load varies the supply current and shaft angular velocity are ximultaneou~ly measured and recorded. A plot of shaft angular velocity against current establishes the algorithm. The algorithm may be expressed in equation form by conventional curve fitting.
As an alternative the algorithm may be simply reduced to a tabular form and stored in memory. However, the tabular form is avoided where possible, because it uses up large chunks of ;~
memory.
It has been found that for ~any motors the algorithm has a fairly linear form over the current range of interest, 80 that motor speed can be derived to a fair degree of accuracy by the expression:
S = -Kl C + Ki, I
where: S is the motor ~peed C is the motor current K~ are constants to be experimentally determined It has also been found that the above expres~ion is not accurate for the conditions which obtain during ~tarting and stopping. However, it i~ generally satisfactory to assume a con~tant average speed ~independent of load) during ~~ 1 T,~
Z008Ds~
,.
these time periods. That speed, again, is determined experimentally.
In general the motor pocition i8 given by the equation:
X = s dt = - K1 C dt + K2T
where T is the total elapsed time.
If the starting time period i8 Gl and the stop period is G2, and the motor has an average speed SA dl1ring :~
these periods, then to a fairly good approximation:
X = SA ~G1 I G~) + X~ ~T - Gl - G2) - Kl C dt For a microprocessor computing at regularly timed intervals t X = SA ~Gl ~ G,) + K~ t - KlC t where the summations are taken over the time interval from G
lS to T-G~.
In operation during a working run the microproces~or begins computing at the instant of motor start , ; by calculating ~or looking up in memory) the term SA ~G~ t ' G~) and placing this value in a position register. ~t thereafter counts time intervals until t = Gl which is the known end of the motor start-up phase. Then the microprocessor calculates (K~ - RlC) t for each computing 200a~;o cycle and adds thi~ into the po~ition regi~ter. This is continued until the position register holds a predetermined target value. The time then is tby definition~ T-G~, and the drive motor is switched off automatically. For a programming run the operator switches the drive motor off manually when a desired position has been reached, and the value then in the position register is stored to become a new target value. In practice, since only a position parameter expres~ing a relative distance i~ required, Gl and Gz are expressed in terms of the number of elapsed computing cycles, and t is set equal to 1Ø
A routine implementing the above technique in SUPER 8 assembly language for foot motor 62 is listed in Table II.
In order to understand Table II it may be observed that the above-noted term Kz - KlC may be rewritten a~
K1 ~C - K~/K ). The program for the foot includes routines for running the foot motor up and running the foot motor down. Within these routines there are subroutines covering the two alternative conditions wherein the me~sured current i8 greater than or less than the no load current.
Referring now to program line noB. 721 - 730 for foot motor up and measured current greater than no load current and making the substitutions:
C = AV FT
K2/K1 = UP NL CUR FT
K = UP NL FAC FT
r;
200846(~) It may be seen that the computer performs a series of steps which calculate the term K~-K~C. The calculated value is added into a register known as ADD FT. Other program listings, not shown, include similar routines for S simultaneously controlling the position of motor~ Gl, G6 and G7.
It will be appreciated that frictional losses, motor slippage and cumulative computing errors will cause error# in the calculated motor position which will grow with the passage of time. Such error~ are small enough to be unobjectionable in an automatically positionable chair. In any event they may be removed by periodically returning the chair to the home position. When thi~ is done the position registers are all automatically zeroed.
While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention 1 which i- defined in the appended claim~.
I
~' 2~)08~
, ..
-l3~ -MID 070 P2 - ~U~ -TABLE I
:
Switch Functions For Hand Control Switch No. Function ~:
131 Select Position 3 132 Auto Return :
133 Select Position 1 134 Program 135 Stop 136 Select Position 2 137 Select Position 4 141 Base ~p 142 Base Down 143 Back Up 144 Back Down ~:~
145 Tilt Up ~:
`; :
146 Tilt Down 147 Foot Up :~
148 Foot Down .
,~
"':
/ ~7 ~!, Z0(~8~ç;O
taQe I~ID~ PODlaTRY T1111LE ~ 17 F~R_FT. aRC
2500 P..D. Super ~ l~acro P6se-bler - Version s.oe.
Input Filena~e: c;\Z511~-id~ark~src\for ft.src Output Filenaee s os\2500ad\~id~a~k\obi\foe ft.obJ
Listing Has Bee~ ted 6~2 .list on 603 .title ~IIO~RK PODlP~TRY TP~ 16, ~17, 6U .subtitle FOR_FT.SllC
6e6 ;
w6 .~OI~aL FOR_~
~ ; , 6~
6~9 EF03 FF FO~ FTs NP ;TEST ONY~ IlEPUlCE IIITH ~ ~RFtURN~ ~H :::
610 EFU 70 D6 ~I RPO s 611 EF~6 7a D7 PUSH RPI jSaVE RE61STER PIONTER ~Q
613 EF08 31 oe SRW ~OOH ;PIONT TO TEIIP ~IORKIN6 REI; `:
614 EFOa 3169 SRP1 ~H ;PlaNT TO Tll XXXX REB
61~ s `:~
617 ; I I I I I l :~
661~8 ; CNr Xll INDEX XX ~DJ XX
62~ ' ; ~
622 5TEST FOR T~E STOP EDGE
62~ ffOC 76 61 C3 TH ~oSK,~llOOODOa9 ;TEST fOR THE LoCK Of ~ T_f~E
,625 EfOf 6D FO 2~ JP 2,SIOP_fT ;f~E SETEC~ED, RUN STOP
626~ 1 627 IFORHULRS fOR RUN THE fOOT IN TK C04N DIRECTION
629 t 629 EF12 76 61 ~0 fT D~N fOLs T~ HRSN~102eOOOQB ;TEST fOR FODT DO~N
636 f~F15 6D EF 9E IP Z,fT,UP,fOL ;NOT RLN~ NEXT 31T
632 EF16 ~6 3C 00 U IN3EX_FT,1a0QH ;CYECK fDR SIRRTIN6 fDRO~ULR
633 f~FlB 6~ f~F ZD JP EQ,ST_UP_~UN FT ;RUN STW DOUN FORDPULa 63~ EflE ~6 3C Ol CP INDEX_Ft,~DOlH ;CHECX FOR RUNNIN6 fORDNULa 635 f~F2l 6D EF 3B JP E4 STRRT_DHN fT ;STMT RUNNIN6 DOUN FORDqULR
636 f~F2~ ~6 3C oe cP I ~ X_FT,1402H ;CKCN fOR RUNNIN6 fORC~ULR
637 f~F2? 6D fF æ JP ESlRUN_D~N_FT ;STMT RUNNIN6 Di~N fORO~ULR
638 Ef2a 8D ff 9E JP FT_UP_fOL jDELAY OR DOES NOT NED TO DE RUN
6U EFZD E6 3~ 20 SET UP D~N FTt LD CNT_fT,~RUN DELaY ;DELAY EET~EEN STaRT oND RUN
6~1 f3F30 a7 71 U Fg ~DE TEXPR7_R7,D~N_ST_CT_FT ;RUN RORYIII~ DFLaY FDR FT_CNT
6~2 fF3~ 79 4~ LD ~DJ_FT,TE~PR7 R7 j~OVE aDJ_FT
6 U EF36 20 3C INC INDEX_FT ;PIONT TO S~ORT
6U EF33 eD FO 2D JP CLRR ;DONE
6~5 ~ . ! ' ; ~
I ~,,*,.,., .,.,'' ~ ..
~ '' X~ O
TABLE I I
-: . P~ge 2 .. ~
~ID~ARK PODI~TRY TaELE ~16, ~17, il~
FOR_FT. SRC
6~6 EF3D a6 3~ 00 STaRT D~IN_FT: CP CNT F~,#100H ;aECK IF STQRT STILL NEDS aDJUSTIN6 6~7 Ef3E El~ 05 JR Nl,ST~RT W~ P~J ;~DJUS~IT STILL IEDE
6~3 EF43 2a 3C INC INDE~ Ft ;PIONT TO RUN
6~9 EF~2 ID F0 2D JP U~ ;D0~E
6S0 EF/~5 P6 U 00 STaRT_D~N_aDJ: CP aDJ_FT,~OOH ;DEC QNC EVERY 2QBS LNTIL IERO
651 EF~B 6D FO 2D JP l,aEaR ;D0K
652 EF48 oa 4~ DEC ~DJ ~ DJUST -I PER 21bS
653 EF~D 60 66 DEC~ l F00T ;STaRT C0tlPEl~T10N
65~ EFU 8D F0 2D JP CLEaR ;D0IE
6S6 EF52 R7 51 30 F9 RUN_DUN FT: LDE TE~PR5 ~5,UP_NL_CUR_fT ;~DNE NO L0RD CURRENT TO RE6 657 EF56 M 05 1~ CP av FT,T~PR5 656 fFS9 P~ 07 JR 6T,aV_6T_N._DUN ;COIIP FOR aVE~6E 611ERtER THRN ND_LOFID
659 EfSB IB 23 JR LT,~V LT_N_~N jCONP FOR ~ERP~6E LE$ TH13N ND_LOP~
660 EFSD 60 6B DECII Tl~_FOOT ;fQUaL, NO CO~IP
661 B5F ~D FO 2D JP 1~1 ;DO~E
~63 Ef62 E~ 14 06 ~V_6T_N. D~l: LD TEI~P~6,RV_Ft ;SaVE COPY OF ~V_FT
66~ EF65 2~ OS 06 SUI~ TEl~PR6,TE~IPRS ;OET ~ DIFFERENOE ~VERP6E TO NO_LOPD
665 ff69 P~7 71 2I f9 LDE tfJlPR7 R7,WN_tL_FPC_fT ;Et W_FaCTOR_FT ~: :
666 Ef6C U 07 06 l~lT TE~IPR6,TEI~PR7 ;~DJUST I~ITH FRCTDR I~ILTI IN
667 EF6F 96 FF 06 DIV TQlPR6,~0fFlt ; .: :
66~ EF72 24 07 U SUB ADD Ft,TE~lPR7 ;P~DD PDJUST~Nt FP~TOR INTO ~N COINT ~ :
669 ff75 36 69 00 SBC TH FOOtR9,~OOOH ;RIPPLE ~RRY THROU6H
670 EF7B 36 6B 00 S~C T~l FGOTR8,~0H ;RIPPLE C~RRY THRal~H
671 EF7a 00 66 OEW T~l FWt 672 EF7D ~D F3 2D JP CLE~R . ;DONE ~
673 ~ :
67~ EF80 E~ 1~ 06 RV Lt NL D'RN: LD TE~PR6,RV FT ;SIWE MPY DF RV_FT
675 EF83 U 06 05 S~9 TEllPRfi,TEtlPR6 ;6ET THE DIFFERB~CE ~ERROE TO ND_LGqD
676 EFB6 R7 71 21 F9 LDE tEHPR7 R7,D~ N F~l: FT ;6ET UP_FPCTM_FT
677 EFBa U S7 06 HULT TEI~PR6,TEIIPR7 ;ADJIIST I~ITH FP~TOR MllTI IN
678 EF6D g6 FF 06 DIV TE~IPR6,~0FFH
679 EF90 Oi 07 U ADD ADD FT,TE~IPR7 ;RDD PWUST~NT FRCTOR INtO RLN COUNT
6BO EF93 16 69 00 aDC Tl~ FOOTR9,N~OOH ;RIPPLE ~qRRY THRDU6H
~I EF96 16 6B 00 aDC THjGoTR9,-000H ;RIPPLE CaRRY THROIIGH
6B2 EF99 20 6B DEC~I Ttl FDDT
6B3 EF9D 6D FO 2D JP a~R ;DON~
685 ~FDRIth~ FGR RLN THE FODT IN T~E W DIRECTII~N
6~6 6B7 EF9E 76 61 ~0 FT UP FQs Tll I~Sll,~01600000B ;TEST FOR FGIDT W
6~ EFal 6D F9 2D JP l,CLE~R ;NDT RUI, NEXT BIT
66g 69~ EFR~ R6 3C OO CP lNDEX FT,tOOOH ;CHECK FOR SToRTlNB FORO~ULa 691 EFa7 6D EF ~9 JP EQ,SET UP W FT ;RUN SETUP UP FOROPU4R
692 ffaa a6 3C Ol CP INDEX FT,taOI~ ;CHECK FOR RUNNIN6 FOROtULa 693 EFRD 0 EF C7 JP EQ,STaRT UP FT ;STRRT RUNNIN6 UP FOROPULR
69~ EF90 R6 3C oe cP INDEX FT,4aqeH ;CHECN FOR RUNNIN6 FORO~ULR
695 EfE3 6D EF DE JP EQ,RUN_UP FT ;STaRT RUNNIN6 UP FORO~ULR
696 EfE6 ~D FO 2D JP CLEOR ;DEL~Y OR DCES NOT NEED TO EE RUN
6n 690 EFS9 E6 38 2a ST UP UP_FT: LD W FT,tRUN DEUY jDELRH EET~EEN ST~RT oND RUN
699 EFEC a7 71 50 F9 LDE TE~PR7 R7, W ST CT FT ~RUN FOR~UL~, DEL~Y FOR FT W
70a EFC8 79 4~ LD PDJ_FT,TE~PR7_R7 ;POUE RDJ_FT
Pdge 3 ~ID~RK PODI~TRY T~aLE ~ 17, ~1 F~R_Ft. SRC
701 EFC2 20 3C INC I~X FT ;PIONT TO ST~RT
7æ EFU aD FO 2D IP CLEP~
7~ EFC7 ~16 3S 0~ STaRT~ Ft: CP CtlT_Ft,~OH ;CHEa~ IF STaRt StllL \~EEDS P~JUStlN~
705 EFbq E~ C5 JR NZ,STaRl_UP_~DS ;~DJUST~IENT STILL I~DED0 706 EFCC ~0 3C INC INDEX_FT ;PlONr TO ~N
7~7 EFOE ~D FO 2D JP CLEQR ;DO~E
70~ I~Dl P6 ~ 00 ST~RT UP NDJ: CP ~DJ FT,NOOII ;DEC ON~E ~ERY 2a~s UN~IL ZERO ::
~Og EFD~ 6D FO 2D JP Z,CLEaR ;DOilE
710 EFD7 00 4~ DEC ~DJ FT ;~WUST -I PER 2bS ::
711 EF`D9 80 6~ I T~l_FQOT ;ST~RT COlWlSAtlON712 EFDa aD f0 2D JP CLEPR ;DONE
71~ EFDE ~7 51 30 F9 RUN_UP_Ft: LDE tf~lPR5_R5,W_llL_OUR_FT ;~IDVE NO LCP~ CURRENT TO ~B `:
715 EFE2 M ~5 IJ~ CP ~V FT,TE~Pa5 j ~ -716 EFE5 ~ 07 JR 6T,M/_6t_1~_UP ;COI~P FOR ~VERR6E 6RE~tER rNaN NO LoaD
717 EFE7 1~ 23 J~ LT,~V_LT_NL_UP ;Cal~P F~R M~Ra6E LESS THIW NO_LOAD : `
716 ffE9 a0 68 I~ tl~_FODT ;EWL, NO C~
719 EFEII ~D FO 2D JP DEQR ;DOIE
721 EFEE E~ V 6T N_UP: LD Ta~PR6,aN_FT ;SaVE COPY ff RJ_fT
722 ~fFl 2~ 05 06 SUII TE~PR6,TE~PR5 ;6t TK DlfFERENCE ~IE~6E TO ~JD_LOPD
723 EFF~ P17 71 31 F9 LDE tE~lPR7 R7,W_N_FaC_Ft ;6ET UP FaCTOR_FT
72~ EFF2 U 07 06 ~lT TEIIPR6,TE~PR7 ;P~JUST ~IITH F~CTO~ IULTI IN
72S EFF6 X FF 06 DIV TE~IP116,~0FFH ;
726 EFFE 2~ 07 U SUB ~DD FT,TEIIPR7 ;~ JUSTl~NT FaCTOR INTO RUN COINT
727 FOOI 36 6g 00 SEIC T~l_FODTR9,~H ;RIPPLE C4MY THRW6H
720 FOO~ 3S 6B 00 SDC T~ FMTRB,1000H ;RIPPLE C~RRY THIDUGH
729 F007 ~0 6B INCll T~l fODT
730 F~llg ~D FO 2D JP Cl~R ;WNE
731 2 .
732 FOOC E4 14 06 ~V LT_NL UPI LD IE~lPR6,a'l1 FT ;SlWE COPY Of ~U FT
733 FOOF 2~ 06 05 SU~ TfllPR5,TEllPR6 ;6ET THE DIFFER~ICE ~tlER~6E TO ND_LOPD
73~ Fel2 ~7 71 31 F9 LDE TE~lPR7_R7,UP_NL_F~_fT ;6ET W_FPCTOR!FT
73S F016 U 07 06 IIULT TEDP~6,Tf~lPR7 ;~DJUST I~ITH FaOTOR I~ULTI IN
.736 FOI9 96 FF 06 DIV Tf~PR6,10FfH J
737 tOIC 0~ 07 U PDD PDD_FT,~IPR7 ;~DD PDJUST~T FaCTOR INTO RUI COlNT
7311 FOlF 16 69 00 P~C T~l FOOT~9,~OOH ;RIPPLE C~RRY T~H
739 fO22 16 60 00 aDC Tll FOOTRô~OOOH ;RIPPLE CMRY TIWU6H
1U t 2S P/O 69 INC~I Tll FOOT
7~1 tO27 ~ FO 2D JP CLEIIR ;DONE
7~2 J
7U ;~IOTOR DO~E, RES~T INDEX PlaNTER
7~ ~ ~7U F02R E6 3C 00 STOP_FT2 . LD INDEX_fT,lOOOH ;IIDTOR STOPPED, RESET INDEX TD 2ERO
7~6 i 7~7 ;C~R TO EXIT
7~ J
7~9 F02D 59 D7 CLE~Rt POP RPI
750 tO2f 50 D6 POP RP~ ;RfPLaC~ ~61ST~R PINTER
751 F031 RF RET ;WNE
7æ J
Line5 P~ bled t 752 ~s5nbly ~rors: O
Claims (15)
1. In a positionable chair comprising a moveable support surface, an electric motor for moving said support surface to a continuously variable series of work positions, a power supply for said electric motor and switch means for selectively connecting said motor to said power supply and causing said support surface to move to said work positions;
improved positioning control apparatus comprising:
timing means for indicating the time consumed during movement of said support surface, sensing means for sensing the current drawn by said motor during said movement, computing means responsive to said timing means and to said sensing means for computing a position parameter related to the position of said support surface, and control means responsive to a target value of said position parameter for stopping said motor.
improved positioning control apparatus comprising:
timing means for indicating the time consumed during movement of said support surface, sensing means for sensing the current drawn by said motor during said movement, computing means responsive to said timing means and to said sensing means for computing a position parameter related to the position of said support surface, and control means responsive to a target value of said position parameter for stopping said motor.
2. The improvement of claim 1 wherein said sensing means comprise a Hall effect device.
3. The improvement of claim 1 wherein said computing means comprise a programmed microprocessor.
4. The improvement of claim 1 wherein said computing means comprise a microprocessor programmed to calculate the speed of said motor as a linear function of said current and to compute said position parameter by repetitively calculating and summing said speed.
5. The improvement of claim 4 wherein said control means comprise means for causing said motor to run to a selected position, means for causing said microprocessor to calculate a position parameter as aforesaid, and means for causing said microprocessor to store said calculated position parameter as a target value thereof when said motor has reached said selected position.
6. An automatically positionable chair comprising:
a plurality of movable support surfaces, an electric motor for each of said support surfaces, each said electric motor being connected for moving its associated support surface between a home position and a target position anywhere within the movement range of that support surface, timing means for indicating movement times for said support surfaces, current measuring means for measuring the currents drawn by said motors, computing means responsive to said timing means and said current measuring means for computing position parameters for said motors which are related to the actual position of said support surface, programming means for indicating target values for said position parameters, and control means for causing said electric motors to operate until the computed values of said position parameters are equal to said target values.
a plurality of movable support surfaces, an electric motor for each of said support surfaces, each said electric motor being connected for moving its associated support surface between a home position and a target position anywhere within the movement range of that support surface, timing means for indicating movement times for said support surfaces, current measuring means for measuring the currents drawn by said motors, computing means responsive to said timing means and said current measuring means for computing position parameters for said motors which are related to the actual position of said support surface, programming means for indicating target values for said position parameters, and control means for causing said electric motors to operate until the computed values of said position parameters are equal to said target values.
7. Apparatus according to claim 6 wherein said programming means comprises means for causing presently computed values of said position parameters to become target values for future control of said motors.
8. Apparatus according to claim 7 wherein said moveable support surfaces comprise a moveable back, a tiltable seat and an elevatable base.
9. Apparatus according to claim 8 wherein said moveable support surfaces further comprise a moveable foot support surface.
10. Apparatus according to claim 7 wherein said computing means comprise a programmed microprocessor.
11. Apparatus according to claim 9 wherein said current measuring means comprise a plurality of Hall effect devices.
12. Apparatus according to claim 11 wherein said control means comprise means for storing said target values during times when said microprocessor is without power.
13. Method of positioning a chair surface comprising the steps of:
using an electric motor to move said surface, repeatedly indicating intervals of movement time of said motor measuring the current drawn by said motor during each of said intervals, using the measured values of said current to calculate the speed of said motor during each of said intervals, multiplying said calculated speeds by the length of said interval to obtain increments of movement distance, summing said distance increments to calculate a position parameter, and stopping said motor when said position parameter has reached a predetermined target value.
using an electric motor to move said surface, repeatedly indicating intervals of movement time of said motor measuring the current drawn by said motor during each of said intervals, using the measured values of said current to calculate the speed of said motor during each of said intervals, multiplying said calculated speeds by the length of said interval to obtain increments of movement distance, summing said distance increments to calculate a position parameter, and stopping said motor when said position parameter has reached a predetermined target value.
14. Method of positioning a chair surface by an electric motor comprising the steps of:
measuring the current drawn by said motor, using the measured value of said current to determine the speed of said motor, integrating said speed over time to obtain a position parameter, and stopping said motor when said position parameter has reached a predetermined target value.
measuring the current drawn by said motor, using the measured value of said current to determine the speed of said motor, integrating said speed over time to obtain a position parameter, and stopping said motor when said position parameter has reached a predetermined target value.
15. Method according to claim 14 wherein said motor speed is calculated as a linear function of said current.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US331,931 | 1981-12-17 | ||
| US07/331,931 US4956592A (en) | 1989-03-31 | 1989-03-31 | Automatically positionable chair |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2008460A1 true CA2008460A1 (en) | 1990-09-30 |
Family
ID=23295969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002008460A Abandoned CA2008460A1 (en) | 1989-03-31 | 1990-01-24 | Automatically positionable chair |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4956592A (en) |
| CA (1) | CA2008460A1 (en) |
Families Citing this family (35)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5214360A (en) * | 1992-03-13 | 1993-05-25 | Den-Tal-Ez, Inc. | Programmable adjustable chair for medical and dental applications |
| GB9223296D0 (en) * | 1992-11-06 | 1992-12-23 | Univ Loughborough | Ergonomic chair |
| US6084519A (en) * | 1993-05-07 | 2000-07-04 | Control Devices, Inc. | Multi-function light sensor for vehicle |
| US5467002A (en) * | 1993-11-05 | 1995-11-14 | Reliance Medical Products, Inc. | Adjustable chair having programmable control switches |
| US5564662A (en) * | 1994-08-15 | 1996-10-15 | Midmark Corporation | Uneven floor compensating system for surgery tables |
| US6038718A (en) * | 1994-08-15 | 2000-03-21 | Midmark Corporation | Surgical table |
| US6754923B2 (en) | 1997-11-07 | 2004-06-29 | Hill-Rom Services, Inc. | Leg section support for a surgical table |
| US6615429B2 (en) | 1999-07-30 | 2003-09-09 | Hill-Rom Services, Inc. | Apparatus for positioning a patient-support deck |
| US6739006B2 (en) | 1997-11-07 | 2004-05-25 | Hill-Rom Services, Inc. | Head section support for a surgical table apparatus |
| WO2002058615A2 (en) | 2001-01-25 | 2002-08-01 | Hill-Rom Services, Inc. | Hydraulic actuator apparatus for a surgical table |
| US6550084B2 (en) | 2001-06-19 | 2003-04-22 | The Brewer Company, Llc | Medical examination table step |
| USD463861S1 (en) | 2001-06-19 | 2002-10-01 | The Brewer Company, Llc | Stirrup for a medical examination table |
| USD458780S1 (en) | 2001-06-19 | 2002-06-18 | The Brewer Company, Llc | Drawer front face |
| USD461900S1 (en) | 2001-06-19 | 2002-08-20 | The Brewer Company, Llc | Top for a medical examination table |
| USD462674S1 (en) | 2001-06-19 | 2002-09-10 | The Brewer Company, Llc | Medical examination table cabinet |
| USD461899S1 (en) | 2001-06-19 | 2002-08-20 | The Brewer Company, Llc | Medical examination table |
| US6802564B2 (en) * | 2001-10-12 | 2004-10-12 | Midmark Corporation | Examination and treatment chair |
| GB2384173B (en) * | 2001-11-22 | 2005-05-11 | Smartasystems Ltd | A power adjustable chair with coded handset. |
| USD496462S1 (en) | 2003-09-29 | 2004-09-21 | The Brewer Company, Llc | Medical examination table |
| US6907630B2 (en) * | 2003-10-10 | 2005-06-21 | Midmark Corporation | Load compensation system for power chair |
| US6915538B2 (en) * | 2003-10-10 | 2005-07-12 | Midmark Corporation | Smooth start system for power chair |
| US6944896B2 (en) * | 2003-10-10 | 2005-09-20 | Midmark Corporation | Line voltage compensation system for power chair |
| US7058998B2 (en) * | 2004-02-06 | 2006-06-13 | Midmark Corporation | Foot control |
| US20060258932A1 (en) * | 2005-05-10 | 2006-11-16 | General Electric Company | Safe motion enabling sequence and system for a medical imaging apparatus |
| DE602006008611D1 (en) * | 2005-06-07 | 2009-10-01 | Philips Intellectual Property | FAILSAFE REMOTE CONTROL |
| US9038216B2 (en) | 2005-07-28 | 2015-05-26 | The Brewer Company, Llc | Medical examination table |
| US7513000B2 (en) | 2005-07-28 | 2009-04-07 | The Brewer Company, Llc | Medical examination table |
| WO2009018422A1 (en) * | 2007-07-31 | 2009-02-05 | Herman Miller, Inc. | Integrated patient room |
| US8176584B2 (en) * | 2008-08-29 | 2012-05-15 | Hill-Rom Services, Inc. | Patient-support apparatus with movable top |
| US9782319B2 (en) * | 2008-11-27 | 2017-10-10 | Medical Technology Industries, Inc. | Articulated chair having universal reclining armrest system |
| US7862123B2 (en) * | 2008-11-27 | 2011-01-04 | Medical Technologies Industries | Articulated chair having universal reclining armrest system |
| US8266743B2 (en) * | 2010-08-23 | 2012-09-18 | Midmark Corporation | Examination table with motion tracking |
| DE102013105869A1 (en) * | 2013-06-06 | 2014-12-11 | MAQUET GmbH | Apparatus and method for controlling an operating table |
| US10786087B2 (en) * | 2017-12-27 | 2020-09-29 | Apex Health Care Mfg. Inc. | Electric bed with independent adjusting device for waist rest |
| US10632037B2 (en) * | 2018-02-01 | 2020-04-28 | Medical Technology Industries, Inc. | Programmable examination and procedure tables and chairs |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4258301A (en) * | 1977-10-21 | 1981-03-24 | Ricoh Company, Ltd. | Servo motor apparatus |
| US4423365A (en) * | 1981-11-09 | 1983-12-27 | The Singer Company | Servo control circuit |
| JPS5913957A (en) * | 1982-07-15 | 1984-01-24 | Fanuc Ltd | Speed detecting circuit |
| US4486797A (en) * | 1982-11-22 | 1984-12-04 | International Business Machines Corporation | Sliding mask variable resolution velocity trajectory for track following servo |
| US4516805A (en) * | 1983-02-15 | 1985-05-14 | Midmark Corporation | Multi-position examination chair |
| US4490659A (en) * | 1983-10-11 | 1984-12-25 | Eaton Corporation | Voltage controlled, variable time delay electronic interval timer for motor control |
| US4706194A (en) * | 1985-12-13 | 1987-11-10 | United Technologies Automotive, Inc. | Multiplex control system for memory seat or the like load |
| US4874995A (en) * | 1986-02-14 | 1989-10-17 | Nippon Seiko Kabushiki Kaisha | Passive seat belt device |
| US4845415A (en) * | 1987-12-08 | 1989-07-04 | Amp Incorporated | Multiplex control system for returning a motor driven element to a stored position |
-
1989
- 1989-03-31 US US07/331,931 patent/US4956592A/en not_active Expired - Lifetime
-
1990
- 1990-01-24 CA CA002008460A patent/CA2008460A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US4956592A (en) | 1990-09-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |