US2043246A - Power press - Google Patents

Description

June 9, 1936.

.T. B. HAWKES POWER PRESS 4 Sheets-Sheet 1 Filed Dec. 3, 1932 INVENTOR. (A;

ATTORNEYS.

June 9, 1936.

T. B. HAWKES -POWER PRESS Filed Dec.

4 Sheets-Sheet 2.

INVENTOR: H -w A T TORNEYS.

June 9, 1936. T. B, HAWKES POWER PRES 5 Filed Dec.

3, 1932 4 Sheets-Sheet 4 .YK T m Patented June 9, 1936 ireo STATES PATENT OFFICE I POWER PRESS Application December 3, 1932, Serial No. 645,565

-8 Claims." (01. 101-3) This invention is a novel power press, and relates more especially to platen presses forleather or other sheet material such as cardboard, fiber and the like. Such type of press is typically illustrated by Bredenberg Patent No. 821,179 of May 22, 1906, or Blake Patent No. 1,285,600 of November 26,1918, wherein are comprised upper and lower platens with power mechanism for causing their relative'approach and separation,.

usually by elevation of the lower platen or bed, through a cam and toggle or other connections, to deliver a heavy squeezing pressure upon the work; so that the leather or other material may be suitably embossed, smooth plated or otherwise treated between the platens of the press; although other modes of causing the lifting of the lower platen may be employed with this invention.

The general objects of the present invention are to afford a power press of improved efficiency, convenience of operation and product. A particular object is to provide for imposing a controllable or variable pause or dwell in the action of the machine while the material is under the heavy pressure, thereby adjusting the time period during which the embossing or plating action is continued. A further object is 'to provide for convenience of operation and control through electrical connections arranged to effect the starting of the machine, thecommencement and the ending of the period of dwell thereof, therestarting after the pause or dwell, and the final stoppage after the pressing is completed and the platens are separated. A further object is to afford an effective detector or safety device to prevent overstrain or undue pressure which might be injurious to the material being treated or even to the parts of the press itself.

Other and further objects of the invention will be explained in the hereinafter following description of an illustrative embodiment thereof or will be understood to those conversant with the subject. To the attainment of such objects and advantages, the present invention consists in the novel power press, and the novel features {of combination, construction and detail herein illustrated or described.

In the accompanying drawings Figure 1 is what may be considered a front elevation of the right hand portion of a power operated platen press embodying the present invention. r

Fig. 2 is a right elevation of the press shown in Fig. 1 with certain parts including shaft bearings and standards omitted to show better the novel features of mechanism. 7

Fig. 3, on an enlarged scale, is a right elevation showing certain details of the escapement or timing mechanism which determines the period of pause or dwell while the material is under compression.

Fig. 4. is a front elevation of the parts shown in 5 Fig. 3, partly in central section.

Fig. 5 is a right elevation on an enlarged scale of one of the safety devices shown at the upper part of Figs. 1 and 2, partly broken out to show the interior construction.

Fig. 6 is a top plan view of the parts shown in Fig. 5, also broken away to show the construction.

Fig. 7 is a diagram of wiring showing a convenient mode of effecting electrical control of the several controllable parts and actions of the apparatus.

Referring first to Figs. 1 and 2, the machine is shown as mounted upon a heavy base 10 above which are the lower frame parts I l and upstanding therefrom at the four corners a system of posts, the outer parts I2 of which may be hollow. On top of the posts I2 is the fixed head [3 of the press, preferablyoccupying the entire space between the four corner posts. The lower frame H, the vertical posts l2 and the top or head l3 are securely and rigidly attached together by a system of interior rods [4 passing through the respective posts, each rod being provided with a lower nut or nuts l5 threaded on to the rod and an upper nut or nuts I6 threaded to the top end of the rod, by which the entire structure may be rigidly and permanently united. The parts ll, l2 and [3 may be constructed of cast iron and the tension rods or bolts M of steel and the latter are therefore, when subjected to excessive stress, subject to slight elongation, which is taken advantage of by the safety device to be described to measure the tension or stress of the machine and to prevent dangerous overstrain.

The fixed head [3 may carry beneath it an upper platen l1, and directly below that is shown the lower platen 19 adapted to be lifted and lowered and shown as lifted to its full height. Depending upon the work to be performed, whether embossing, fiat plating or the like, the upper and lower platens may be provided with dies, plates or embossing members. The lower platen I9 is shown mounted at the upper side of a rising bed 20, which has several underneath extensions all marked 20 and at the four corners slides or shoes 2! adapted to run on tracks or ways 22 carried by the corner posts of the machine, so that the bed may rise with true paraling omitted from Fig. 2.

lel motion toward the head and descend therefrom; substantially as in said prior patents.

While the means for lifting the bed might be hydraulic or of various mechanical forms it is shown, as in said patents, as comprising a system of toggles. Thus extending directly below the bed near the front and back are upper toggle links 24, these having their lower ends pivoted to the free upper ends of the lower toggle links 25 fulcrumed on the lower frame II of the press. The straightening of the opposed toggles 24, 25 affords very powerful upward thrust of the bed 20. This spreading action may be performed by a third toggle pair 2? each connected to a pivot extension 26 of one of the toggles 25, and the two links 21 being mutually connected by a central toggle pin 28 which may have its ends suitably guided for central vertical motion, for example as shown in said prior patents. The central pin of the spreading toggle 21 is shown as carrying a roll 29 which rests upon an open cam 30 mounted on the main shaft 3| of the press. The cam 30 has an outer dwell which is shown as holding the bed in its lifted position, with inclines connecting said dwell with an inner dwell on which the roller rests when the bed is in its fully lowered position. If the shaft 3| be rotated continuously the cam 35)- will alternately lift and lower the press bed with regular action, holding it lifted for a period depending upon the angular length of the outer dwell of the cam 30. According to the present invention however, as will be further explained, the shaft and cam are to be brought to rest while the bed is fully lifted and the sheet material is under compression, so that the period of compression may be prolonged to a controllable extent as may be required for different classes of work. The cam may be designed with shortened dwell and the balance of the cycle altered to the improvement of the other parts of the cycle of operation, if desired in any case.

The power drive of the main shaft 3| may contain reducing gears described as follows. On the right end of shaft 3| is a large gear 33 which is in mesh with a pinion 34 mounted on a countershaft 35 which in turn carries a large gear 36 in mesh with a pinion 3'! mounted on a clutch shaft 38 driven from a high speed power shaft 39 through a clutch device to be described. The

shafts 3| and 35 may take their bearings in the.

lower frame H of the press, and in Fig. 1 is shown a standard 4| in which the shafts 35 and 38 take their bearings, this standard however be- The power shaft 39 turns in a bearing 42, and at its left end it may have another similar bearing, the shaft being rotated from any source of power such as belt and pulley, or direct drive by electric motor, the gear system 31, 36, 34, 33 reducing the speed of the main shaft to a suitable speed to deliver one complete cycle of operations for each rotation of the shaft.

While describing the shafts 38 and 39 and the power drive thereof the controllable clutch and brake may advantageously be described. The clutch is preferably magnetic and operated by electric current. It is shown in Figs. 1, 2 and 7 as comprising a pair of disks 43 and 44, one of which carries a magnet coil 45 so that by applying current to the coil the disks are drawn together for frictional drive, whereas discontinuance of current releases the drive. Two insulated contact rings 46 are shown from which extend conductors for electric. control of the clutch. The

brake shown in Figs. 1, 2 and '7 comprises a drum 48 on the clutch shaft 38, such drum. being engaged by a brake band 49 fixed at one end and having its other end secured to a brake lever 50 so that swinging of the lever applies and releases the brake. A strong spring 5| is indicated as pulling the lever and tending always to apply the brake and stop the shaft 38. For releasing the brake there is shown a magnet or solenoid 52 arranged to pull upon the lever 50 and thus relax the band 49. The solenoid is operated through suitable electric conductors as will be further described. The magnetic clutch and brake may be of conventional character, for example of the so-called C-H type.

The safety device preventing overstrain to the frame parts and injury to the sheet material may be duplicated at each of the four frame rods l4 and may be described with reference to one of them as follows. Adjacent to each vertical frame rod I4 is shown an upright bar or tie rod 55 having its lower end anchored in a fixed position by a plate 56 mounted at the bottom end of the press or frame rod. The upper end of the bar extends loosely through a similar plate or table 51 mounted at the top end of the press rod. The top end of the tie rod or bar is threaded and carries a pair of lock nuts 58 constituting a stop or contact for the operation of the detector or safety device. Electrical control is preferred and a switch box 59 is shown mounted on the top plate 51. A contact lever 60 best shown in Figs. 5 and 6, has anexternal short arm 6| contacting against the underside of the stop or contact nuts 58. The

lever is fulcrumed on a ball bearing near its.

short end. The long end of the lever 60 is connected by a link 62 with a pivoted plate or segment 63, the shaft of which has an exterior index finger or pointer 64 normally resting at the zero mark on a calibrated scale 65 at the exterior of box 59 The stop nuts 58 are initially adjusted so that the pointer 64 will rest at zero, and any elongation of the main or press rod |4 relatively to the, tie bar or rod 55 will be indicated upon the scale in a manner to disclose the amount of strain or elongation of the rod. In a sense the tie rod relatively shortens and so swings the lever 60 and the scale pointer. In this way the strain may be visually determined at each of the four corners of the machine and in case of overstrain or excess pressure suitable corrections of action may be effected.

To. afford an automatic device the following further mechanism is illustrated. Projecting from the link 62 is a finger 66 which thus is lifted, with a multiplied motion, when the rod I4 is elongated by its strain. Spaced a suitable distance from the finger 66 is a contact 61, which may be a micrometer screw and therefore finely adjustable to. bring about a tripping action at any desired overstrain. The contact screw 61 is mounted on a depending finger or arm 68 fulcrumed at. 69.. The arm 68 acts as a latch or trigger. It is held normally in place by a tension spring 10 but will be swung leftward when the rise of the finger 66 actuates the contact 67. A notch or shoulder TI is provided between the latch arm 68 and a pivoted switch lever 12. The switch lever or carrier 12 is thus normally held in the position shown in Fig. 5 but it is swingable about a fulcrum 13 and has a lateral arm 14 pulled by a spring 15 tending to swing the switch out of normal position. While the switch might be of various types it is shown as comprising a mercury tubedevice 16, for example with mercury effecting electrical connection between metal partsembedded in .the two depending legs of the tube as shown, this being a conventional form of mercury switch. When the overstrain on the rod l4 causes the arm 68 tobe swung to the left the spring 15 comes into action to tilt the mercury tube and thereby break the electrical connection between the terminals in the depending legs of the tube. At will the switch lever and tube may be swung back to their normal horizontal position by depressing a finger piece or resetting button 18 until the catch or shoulder H engagesagain in the notch or shoulder of the lever; and this finger piece by its elevation thus visually shows that the switch has been tripped and requires resetting.

, As indicated in Fig.7 the four mercury switches 16 at thefour corners of the machine may be connected in seriesin a.closed circuit, so that excessive strain or compression at any one or more of the rods or cornerswill cause the opening of the corresponding switch or switches and the breaking of the circuit, which may be arranged immediately to open the driving clutch and apply the brake of the machine; or the relief against further overstrain might beby release of a hydraulic resistance, for example in the upper platenor head as in the Blake patent. Coming next to the mechanism for timing and adjusting the extent of pause or dwell of the pressing action, this is mounted on a bracket 80 attached to the machine base. On top of the bracket 80 is a hollow base 8| for a cylinder 82 preferably containing a light oil but in some cases operable like a dashpot by air. The cylinder is shown as extending vertically upward above its base and its top end is closed by a cylinder head 83 above which is arrangedan upward extension .or bracket 84 carrying at its top end a guide 85., A piston rod 81 slides through the guide 05 and through thecylinder head 83, and at its top end is provided with a heavy weight 88 exerting a constant lowering force for the operation of the piston 90, although spring or other pressure might be used. Pinned to the piston rod and extending transversely through the bracket 80 is a crosshead 92, one outer side of which carries a roll 93 by which thehead, rod and piston may bejlifted at certain times and then released to be lowered, by the pressure of the weight 88,. The piston is shown partly lowered/and on its way down, after release by cam 95 to be described, and its extent of lift and drop is indicated by the dotted lines showing the highest and lowest piston positions in Fig. 4.

The intendedoperation is thatIthe piston 90 shall rise as the pressbed rises, and shall reach the top of its stroke as the lower platen of the press reaches the top of its stroke placing the leather or material 'under its fullpressure, at which timelcertain actions will occur to arrest the motion of the machine, while the piston is at the same instant released to descend slowly until, at the end of its descent, it brings about certain control to restart the. operation of the machine. Whilethe piston and rod might be lifted by a direct mechanical connection with the lifting parts of the press bed it is preferred to effect the lifting by a special cam 95 shown mounted at the right end of the main shaft 3|. This cam 95 has a substantially spiral outer contour, as bestseen in Figs. 2 and}, to lift steadily the rod and piston, but terminating abruptly to release them at the desired point of time, Fig. 3 showing thecam having reached the release position and having come to rest with themain shaft, and the roller 93 having passed off the cam and started its descent with the rod and piston. V

The fluid circuits are sufiiciently shown in Fig. 3. The cylinder base 9| is shown with a transverse passage 91, seen also in Fig. 4, which connects directly with the cylinder space below the piston. At one end of the passage 91 is a fluid inlet port 98 conducting liquid or air into the cylinder, preferably a light oil. At the opposite side is an outlet port 99 for the return flow I of the liquid. Analogously, at the top of the cylinder, are an outlet port I90 and an inlet port When the piston is being lifted the liquid above it readily passes through top outlet port I00 and back to bottom inlet port 98 by the following routeor idle circuit. A pipe I03 extends outwardly from outlet I90 and this is connected by a downtake pipe N14, with suitable unions and other fittings, the pipe 894 in turn delivering into a check valve I which permits flow only toward the bottom inlet 98, thus admitting liquid below the piston and permitting the free rise of the piston. The check valve however prevents reverse flow so that when the piston is descending the flow will be through the other circuit to be described- A fluid supply reservoir I96 is shown delivering into the circuit l03|04, and serving to discharge any air that may get into the system.

,The operative fluid circuit may be as follows. When the piston has been released and is descending under the pressure of weight 88 the liquid below the piston passes into and through the cylinder bottom outlet 99 and thence into an uptake pipe I08 which leads to an adjustable valve I09, preferably a needle valve-adjusted by a handle I I0, which may be in the form of a disk graduated to cooperate with an indicator or finger III, the needle valve I09 delivering into the top inlet [0| of the cylinder. The speed of descent of the'piston may thereby readily be regulated by the adjustment of the needle valve; for example the valve may be set so that the piston will occupy one minute more or less in descending through the cylinder, thereby prolonging the pressing pause or dwell of the machine to that extent. In effect the usual cycle is interrupted or suspended for the introduction of the slow release or escapement action, of predetermined period, so that the cycle is prolonged to that extent, to the enhancement of the pressing or embossing action, with the aid of the usual heat of the head, bed or both, and without the need of unduly or injuriously increasing the intensity of pressure.

As already explained, the main shaft 3|, and therefore the large gear 33, make a single rotation in one cycle or operation of the machine. The spiral or mutilated cam 95 is mounted directly on the shaft end and therefore is accurately timed with the shaft rotation. When the roll 93 runs off the cam, which it is about to do in Fig. 2 but which it has done in Fig. 3, soas to trip or start the extra pause or dwell action of the machine, the rotation of the shaft should be stopped, and means are provided for effecting the stoppage preferably at this point of time, at or immediately after the release of the escapement or piston device. The platen operating cam 39 having a dwell of 90 more or less, the precise point of tripping the piston and stopping the machine within this part of the cycle is not important, as it obviously might occur to the same eifect at any time before the main cam 30 has rotated far enough to start the descent of the bed and the release of the pressure on the goods. In fact, the total period of pressure on the goods between the platens of the machine will usually be approximately the sum of the period represented by the dwell of the cam 30 and the period represented by the descent of the piston 90 during which the shaft and cam are pausing in their rotation.

Preferably the temporary stoppage of the ma-- chine is effected approximately simultaneously with the release of the piston, soon after the main cam 30 has fully lifted the lower platen, and the construction is shown so adjusted. To bring about the temporary stoppage or pause as described there is shown, mounted on the bracket 80, a stopping switch I I4 having a contact finger H5 for operating it, this finger with its roll standing in the path of a contact or trip H6 mounted near the rim of the large gear or wheel 33. The tripping contact or cam H6 is of short length and is mounted on an arcuate rib or track II! in a manner to be adjustable to time the stopping action. The wheel contact H6 in Fig. 2 is approaching the switch and in Fig. 3 is shown as having operated the switch H4 and having come to rest with the wheel or gear in its operating position, where the rotation of the machine 'has been brought quickly to a stop by the action of the switch H4 through electric connections or circuits to be described extending to the magnetic clutch 43, 44 to open it and to the magnetic brake 48, 49 to apply it. The trip H6 and switch H4 thus hold the circuit open, and the machine stopped, until otherwise restarted as will be described; and immediately after be-- ing restarted the trip H6 rides out from under the finger H5, and'so closes the switch H4 for completion of the cycle.

Before describing the circuits by which the safety switch 59 or the stopping switch H4 may bring about the stoppage of the machine by the releasing of the clutch and the applying of the brake, the restarting switch will be described by which the machine is again set in motion following the pause and as the piston 90 reaches its lowered position. On the side of the cylinder 82 is shown a bracket H9 on which is mounted the restarting switch I consisting of a box con-- taining the elements to be described. The switch lever I2I is pivoted in the box at I22 and a compression spring I23 is arranged to lower the outer end of the lever and thereby lift its inner end and open the switch. ()n the lever is shown the movable contact member I24 and below it is the complementary or stationary member I25, each of these being attached in an insulated manner, and wire leads being shown extending from them to the circuits to be described. The inner or left end of the switch lever I2I extends beyond the switch box to where it carries a pin I2! by which the lever may be swung by the de scent of the piston. For this action the cross head 92 on the piston rod is shown as provided with a depending finger or wedge bar I28 held normally in vertical position by spring I29. The lower end of the finger has a wedge or cam surface I30 to cooperate with the pin I21, and above the apex of the cam surface is a recess I3I adapted to accommodate the pin when the cam surface has passed below the pin. The finger I28 is shown part way down; in its further descent its wedge end I30 depresses the pin I21 and switch lever until contact I24 meets I25,

thus restarting the machine and continuing the motion long enough to permit the reclosing of switch H4. The spring I29 then yields and as the finger comes to bottom position, shown dotted, it may snap past the pin and let the contacts separate at once, due to the recess I3I, thus reopening the restarting switch and circuit so that emergency stops will not be prevented. On the subsequent rise of the finger the spring may again yield to allow the wedge finger to pass the pin, without eflect on the then moving parts.

While the circuits for the various controls and operations might be indefinitely varied, to altord an electrified press, an advantageous arrangement is that shown in Fig. 7. From a generator G or other source, affording for example 230 volts D. 0., the current is shown carried by a pair of wires I which lead to and through a hand closed double pole switch I4I provided with fuses. Beyond the switch and fuses are parallel wires I42 leading to a main switch I43 arranged to be opened and closed automatically as will be described. Beyond the automatic switch M3 are parallel wires-I44 leading to the circuits of the clutch 43, 44 and brake 48, 49. Thus from one wire 4 is a wire I 45 leading to one of the brushes of the clutch, the other brush connected by wire I46 with the other wire I44. In parallel, the brake is connected with the one wire I44 by a wire I41 leading to the solenoid 52 and therebeyond a wire I48 leading back to the other wire I44. The hand switch I4I being normally closed the automatic switch I43 controls the clutch-v and brake; when the switch is closed the clutch is applied and the brake is released, and vice versa.

The main switch I43 is shown as a double pole switch, and it may for example be closed magnetically by the pull of a magnet or solenoid indicated by its core I49 and coil I 50, the deenergizing of the same releasing the switch, to be opened for example by a spring. The main switch control circuit, while normally closed, is shown open to correspond with Figs. 1-6, and may be substantially as follows. From the switch solenoid coil I50 extends a wire I5I to one of the wires I42, the circuit passing thence through the source of current and back by the other wire I42. From there the circuit continues, when the switch I43 is closed, through one of the arms of said switch, and thence by wire I53 to a normally closed manual switch or button I54, connected in turn by wire I 55 with the stopping switch H4, normally closed but shown open, seen also in Figs. 3 and 4. From there the circuit is continued through wire I56, manual or button switch I 51, the wires I58 of the safety circuit which includes the four mercury switches I6 in series, and finally by wire I59 back to the solenoid coil I50. Corresponding with Figs. 1-6 the four mercury switches are all closed, but the circuit is interrupted due to the fact that the stopping switch I-I4 has been opened, as in Fig. 3, by the trip contact H6, in consequence of which the magnetic switch I43 is open, the clutch is released and the brake is applied. When, a little later, the stopping switch H4 is closed the circuit is not closed, as the magnetic switch I43 is open, but the circuit is all set to be closed by the restarting switch, whereby the brake is released and the clutch is closed, for continued advance of the main shaft.

The restarting switch I20 is in a circuit shunting the initial starting switch I13 to be described.

Thus in Fig. 7 the restarting switch is shown open, as it normally is, and connected by wire I62 with the wire I55. Beyond the switch extends a wire I63 to a cutout switch I64 from which extends wire I65 to the long return wire I66 leading back to one of the live wires I 42. When the restarting switch is closed after the stopping switch has been closed this completes the circuit through the coil I50 and source G causing the reclosing of switch I43 and the restarting of the machine.

Supplemental to the stopping switch H4 is a normally open cutout switch I68 which may be closed when desired to cut II4 out of operation. The normal or main circuit may be broken by opening the button switch I54 or by the switch I51, which latter may be used for the final auto- -matic stoppage at the end of the cycle. A shunt circuit I10 is shown shunting the safety switches and containing a normally open button switch "I, so that by closing this switch the current is passed around the safety switches, permitting closing of the clutch and rotation of the machine notwithstanding that one or more of the safety switches has been operated or is out of order.

An initial starting switch I13 is shown paralleling the local circuit of the restarting switch I20, the starting switch I13 being interposed in a wire I1 4 extending from the wire I53 or I55 to the wire I66. By closing either the restarting switch I20 or the initial starting switch I13, both of which are normally open, the circuits .are made as follows. Both of these switches conwith the wire I55 which extends through the normally closed switches H4 and I51 and the wires I56, I58 and I59, the latter leading to the coil I50 of the solenoid, the other terminal of the coil connected by the wire I5I to .the other live wire I42. In this way thesolenoid closes the main switch I43. As soon as the switch I43 is closed, by either means, this automatically establishes a circuit which maintains the switch closed notwithstanding the opening of both the starting and restarting switches. Thus when the switch I43 is closed this provides. a circuit from one of the live wires I42 through wire I53, switch I54, wire I55, switch H4 and conductors I56, I58 and I59 through the solenoid coil and back by wire I5I to the other live wire I42. This establishes running condition, with the clutch closed and brake open, but subject to immediate stoppage upon the opening of the stopping switch H4 or of the button switch I54 or the switch I51 or any of the safety switches 16.

When it is desired to operate the machine without the automatic stopping switch H4 and restarting switch I20 it is only necessary to close the special switch I68, thus cutting out the switch II4, whereupon the closing of the initial starting switch I13 will put the machine into operation, while the opening of any of switches I54, I51, I68 or 16 will bring about the stoppage.

The final automatic stopping of the machine may be effected by the opening of the switch I51 in the main circuit, for which purpose the switch I51 may be similar to the switch H4 and cooperate with the same tripping contact I I6 or a similar contact, properly timed, so as to open the clutch and close the brake at the end of the cycle when the lower platen has been dropped to its lowest position; or on the other hand this final stopping might be effected by the switch II4 itself, cooperating with a second trip contact Simiand another piece of material substituted by hand, or the Well known scheme of progressively advancing a web of material step by step through the machine between pressing operations may be followed. The starting of the machine for the new pressing may be simply effected by the manual closing of the button switch I13, which closes the shunt circuit I55, I14, I66 thus energizing and closing the magnetic switch I43; and as soon as the machine is well started the switch I13 may be released as the main circuit will have been established through one arm of switch I43 and wire I53. When thus restarted the machine continues in motion until after the lower platen is fully raised and the material is under full pressure, when the trip II6 acts to open the switch II4 thus opening the clutch and applying the brake and so holding them until, after the slow descent of the piston, the restarting switch I26 is closed, thus first causing the restarting of the machine and thereupon the closing of the switch II4 to maintain operation until the final stoppage.

The described magnetic brake device constitutes a stop means for causing stoppage of the main or operating shaft when the drive is discontinued; but where the drag or natural friction of the machine is sufficient .to cause quick stoppage when drive ceases, as is usually so especially at the extremes of platen movement, such drag may constitute a stop means without need of a brake device that is applied and removed.

The described clutch constitutes a power drive means and throw-off means for applying power. and for discontinuing drive and permitting" stoppage of the shaft; and is representative broadly of any power throw-off such as a belt-shift, or a switch to cut off current to a driving motor, serving the same general purpose.

The stopping switch I I4 is in the main control circuit while the restarting switch I20 is in the shunt control circuit, these circuits operating through connections, in this case the magnetic switch I43 and operating circuit I44 to operate the drive means or clutch, opening and later closing it, and preferably also closing and lateropening the brake means.

The fluid operated escapement device, dash pot or piston and cylinder constitutes a retarded circuit control means for operating the restarting switch by delayed closing of the contacts thereof, and is representative of any retarding circuit controller such as clock train mechanism;

There has thus been described a power press embodying and illustrating this invention and attaining its objects; but as many matters of combination, construction and detail may be variously modified it is not intended to limit the invention to such matters except so far as specifled in the respective claims.

What is claimed is:

1. In a power driven platen press for embossing or pressing leather or like material having a frame and an operating shaft with connections for forcibly advancing or lifting the movable platen toward the other platen and causing its retraction in each cycle of the press; a power drive and throw-off means or clutch for driving and discontinuing drive of the shaft, a stopping device or switch connected for temporarily throwing off the drive to stop the shaft and timed to operate when the movable platen is in full-pressure position, a timed cylinder and piston device set into operation when the movable platen is in full-pressure position and having a predetermined period of operation during which the shaft pauses, and the material remains under full pressure, and a restarting device or switch set into operation when the escapement device reaches the end of its period and connected to restore the drive of the shaft and complete the cycle of the press, the cylinder and piston device having a flow adjusting valve or escape to vary the pause of the shaft.

2. A power press as in claim 1 and wherein is a mechanical connection to lift the piston to the top of its stroke as the movable platen rises to full pressure position and to release it for gravity descent as the shaft comes to a pause, and an adjustable fluid escape from the cylinder bottom for controlling the rate and period of descent of the piston.

3. A power press as in claim 1 and wherein the cylinder carries liquid and has two external closed circuits, the first liquid circuit having an adjustable valve to regulate the piston speed, and the second circuit having a check valve permitting only return fiow of liquid.

4. In a power driven platen press for embossing or pressing leather or like material having a frame and an operating shaft with connections for forcibly advancing or lifting the movable platen toward the other platen and causing its retraction in each cycle of the press; a drive means or clutch for driving and discontinuing drive of the shaft, a stopping switch for temporarily causing discontinuance of drive to stop the shaft and timed to operate when the platens are in material pressing relation, a timed retarding device set into operation when the platens are in pressing relation and having a predetermined period of delay during which the shaft remains stopped, and the material under pressure, a restarting switch operated when the retarding device reaches the end of its period to cause resumption of drive of the shaft and completion of the cycle of the press, and electrical control circuits containing said stopping and restarting switches and having connections for operating said drive means according to the operations of the switches; such control circuits comprising a main circuit containing the stopping switch normally closed during the running of the shaft, and a shunt circuit containing the restarting switch normally open; with timed means to open the stopping switch thereby to stop the shaft when the platens are in pressing relation, and means thereafter to close the restarting switch and shunt circuit at the end of the retarding period thereby to restart the shaft.

5. In a power driven platen press for embossing or pressing leather or like material having a frame and an operating shaft with connections for forcibly advancing or lifting the movable platen toward the other platen and causing its retraction in each cycle of the press; a drive means or clutch for driving and discontinuing drive of the shaft, a stopping switch for temporarily causing discontinuance of drive to stop the shaft and timed to operate when the platens are in material pressing relation, a timed retarding device set into operation when the platens are in pressing relation and having a predetermined period of delay during which the shaft remains stopped, and the material under pressure, a restarting switch operated when the retarding device reaches the end of its period to cause resumption of drive of the shaft and completion of the cycle of the press, and electrical control circuits containing said stopping and restarting switches and having connections for operating said drive means according to the operations of the switches; such control circuits comprising a main circuit containing the stopping switch normally closed during the running of the shaft, and a shunt circuit containing the restarting switch normally open; with timed means to open the stopping switch thereby to stop the shaft when the platens are in pressing relation, and means thereafter to close the restarting switch and shunt circuit at the end of the retarding period thereby to restart the shaft; the stopping switch opening means constructed to reclose the switch upon the restarting of the shaft, and the restarting switch closing means constructed to reopen the switch upon the reclosing of the stopping switch.

6. In a power driven platen press for pressing leather or like material having a frame and an operating shaft with connections for forcibily shifting the movable platen toward the other platen and causing its retraction in each cycle of the press; a drive means for driving and discontinuing drive of the shaft, a stopping switch for temporarily causing discontinuance of drive to stop the shaft and timed to operate when the platens are in material pressing relation, a timed liquid flow device set into operation when the platens are in pressing relation and having a predetermined period of liquid escape during which the shaft remains stopped, and the material under pressure, a restarting switch operated when the liquid flow device reaches the end of its period to cause resumption of drive of the shaft and completion of the cycle of the press, and electrical control circuits containing said stopping and restarting switches and having connections for operating said drive means according to the operations of the switches.

7. A press as in claim 6 and wherein the control circuits comprise a stopping switch circuit, and a restarting switch circuit, said liquid flow device arranged to operate the stopping switch to stop the shaft and thereafter to operate the restarting switch at the end of the flow period thereby to restart the shaft.

8. A power-driven opposed-platen press for embossing or pressing leather or like material comprising an operating shaft with connections for forcibly lifting the movable platen toward the other platen and causing its retraction in each cycle of the press; a power drive and throw-off means for driving and discontinuing drive of the shaft, a stopping device for temporarily throwing off the drive to stop the shaft and timed to operate when the movable platen is in fullpressure position, an escapement member fitted to travel in reverse directions, as upwardly and downwardly, along a given path between normal lowered and displaced elevated positions, driven connections for elevating the escapement member along such path into displaced position when the movable platen is advanced into full-pressure position, means operating independently of the shaft and power drive for controlling the esoapement device to have a predetermined period of progressive descending return travel from displaced to normal position, during which descent the shaft remains stopped and the material under full pressure, means for adjusting the period of the operation of the controlling means independently of the power drive and shaft operation, and a restarting device set into operation when the escapement member has reached its normal lowered position to restore the drive of the shaft thus to complete the cycle of the press.

THOMAS BLAIR HAWKES.

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