US2203354A - Power transmission - Google Patents

Description

J1me 1940- F. T. HARRINGTON ET AL 2,203,354

POWERTRANSMISSION Filed Oct. 12, 1957 s sn'eets-sheet 1 'INVENTORS 1 BY 5 m wf/M v ATTORNEY June 4, 940. F. T. HARRINGTON ET AL 2,203,354

' POWER TRANSMISSION Filed Oct. 12. 1937 5 Sheets-Sheet 2 INVENTORS BY :1; Rwy "wad ATTORNEY 1 1940- F. 'r. HARRINGTON ET AL 3,354

POWER TRANSMISSION Filed Oct. 12, 1937 3 Sheets-Sheet 5 INVENTORS ZZ aw 7. BY JRa/qwnd ,a/W1/ x, ATTORNEY Patented June 4, 1940 UNITED" STATES POWER TRANSMISSION Ferris.T. Harrington, L Raymond Twyman, and James Robinson, Detroit, Mich, assignors to Vickers Incorporated, Detroit, Mich., a corporation of Michigan Application October 12, 1937, Serial No. 168,618

Claims. (Cl. 242-55) This invention relates to power transmissions and more particularly to those of the type comprising two or more fluid pressure energy translating devices, one ofv which may function as a pump and another as a fluid motor. The invention is shown and described as embodied in a device for feeding strip material intermittently to a blanking press, although it will be understood that this is but one example of many applications to which the present invention is adaptable.

It is an object of the present invention to provide a hydraulic power transmission system and control'mechanism therefor which may operate a set of pinch rolls for feeding apredetermined length of strip material from a reel into a blanking press. In devices of. this character the timing of the strip movement and its acceleration and deceleration must be under accurate control so that exactly the correct length'is fed into the press at each operation, and unnecessary waste of material avoided.

It is also an object to provide in devices of the character described means for automatically controlling the speed of a reel so as to operate at a. speed which'is an average of the intermitt'ent speed of the pinch rolls.

It is a further object to provide a hydraulic transmission system of the type including a pump and a motor wherein a novel arrangement of reversing valves and relief valves is provided Which permit utilization of a single relief valve both for safety protection during normal forward or reverse operation and also for use as a brake when the load overhauls the fluid motor during deceleration.

A further object is to provide a hydraulic power transmission system wherein a single pump is utilized both for supplying fluid for driving purposes and also for supplying fluid for control purposes wherein control pressure is made available=even during periods when the load is overhauling the.- fluid motor.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying .drawings wherein a'preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a fragmentary side view of a blanking press provided with an automatic feed mechanism incorporating a preferred form of the present invention.

Fig. 2 is a schematic view of the hydraulic circuits incorporated in the feed mechanism of Fig. 1.

Fig. 3 is a schematic view of the electric circuits incorporated in the feed mechanism, of Fig. 1.

Referring now to Fig. 1 there is shown a blanking press l0 having a bed I2 carrying a blanking die l4 and a vertically reciprocating slide l6 carrying a blanking punch H3. The construction of the press per se forms no part of the present invention. Positioned at one end of. the press is a combined feeding and straightening device 20. Beyond the feeding device 20 there is mounted in a pit 22 a cradle type unreeler 24.

strip laterally in the rolls 26 and 32. The lower 2 roll 32 is driven by means of bevel gearing 42, shaft 44, and bevel gearing 46 from a'hydraulic transmission indicated generally at 48. The latter is driven by an electric motor 50 (see Fig. 3). An electric timing and control panel 52 is 20, the timing mechanism thereof being driven by a worm 54 meshing with a worm wheel, not shown. The control panel 52 includes an adjustable pointer 56 for determining the length of strip which is fed in one cycle, an adjustable pointer 58 for determining the point in the cycle at which deceleration is started, a push'button switch 60 for initiating a cycle of operation manually, a toggle switch 62 for switching from automatic cyclic operation to inching operation, a toggle switch 64 for switching betweenmanual initiation of. cyclic operation and press controlled initiation of cyclic operation, and a control lever 66 for effecting inching forwardly or backwardly when the toggle switch 62 is in inching position. Mounted on the main frame of the press adjacent the slide I6 is a trip switch 68 operable by a flipper cam carried on the slide. The latter closes the switch 68 during the upward stroke of the slide. 16 but is ineffective to close switch 68 on the downward stroke. Either the switch 68 -or the cam 10 may be vertically adjustable for varying the point in the press cycle at which the switch is closed.

' mounted in the front wall of the feeding device 7 by a chain 18 from a variablespeed hydraulic transmission 80. Idler rolls 82 are also mounted.

between the frames 12 for assisting in positioning a reel of strip material 84. The transmission 80 is driven from an electric motor 86 (see Fig. 3) and is provided with a handwheel 88 for varying the speed bf the cradle rolls 16. A three-way limit switch is mounted adjacent the reel 84 and is provided with an operating lever 92,

adapted to be contacted by the strip 30 when a predetermined amount'of slack occurs between the unreeling device 24 and the feeding device 20 (see the dotted lines 94).

Referring now to Fig. 2 the hydraulic circuit of the power transmission 48 is there shown diagrammatically. The transmission comprises essentially a variable strbke pump 96 and a fixed stroke motor 98. The shaft I00 of the pump 96 is driven by motor 50 while the shaft I02 of motor 98 drives bevel gearing 46. The pump 96 and motor 98 may be of any suitable construction and are illustrated as of the type shown in the patent to Hans Thoma, 1,931,969. The pump 96 delivers fluid into a conduit I04 which communicates with a port I06 in a three-way solenoid operated valve I08. A branch conduit IIO leads to a check valve 1 I2 whence a conduit II4 extends to the pressure side of a relief valve II6. A suction conduit I I8 of pump 96 extends into the sump I20 and may be provided with a filter element I22. In the mechanism of Fig. 1, the sump I20 is formedwithin the frame or housing of the feeding device 20. The three-way valve I08 is provided with a port I24 which connects by a conduit I26 with a port I28 in a solenoid operated four-way valve I30. A branch-conduit I32 extends to the motor 98 and forms the delivery conduit thereto when the motor is operating in a forward driving direction. A port I34 of the valve I30 is connected by a conduit I36 to the relief valve I I6 at the same point where the conduit I I4 connects thereto. A third port I38 of the valve I30 connects by a conduit I 40 to the discharge side of a resistance valve I42 which may be similar in construction to the relief valve II6, but incorporates in addition a check valve I43 opening to flow from conduit I40 to conduit I44. The pressure side of the valve I42 is connected by a conduit I44 to the opposite port of the motor 98.

Suitable exhaust connections I46, "I48, I50 and I52 are provided at the ends of the valves I08 and I30. The valves I 08 and I30 include spools I54 and I56 which are shiftable between their upper and lower extreme positions by solenoids A, B, C and D. When shifted to either position the spools are adapted to remain in that position until positively operated by the opposite solenoid, The valves I08 and I30 may be identical in construction, the valve I08 having a port I58 which is plugged, thus making the valve a three-way valve. The discharge port of the valve II6 connects to the sump by a conduit I60.

Each of the valves H6 and E42 includes a spool I62 reciprocable in a bore I64 and urged downwardly by a spring I66. Atthe lower end of the spool I62 there is provided a small piston I68 which is subject to pressure at the pressure side of the valve through a small conduit I10. Whenever this pressure exceeds the setting of the spring I66, the valve spool is caused to rise opening communication between the pressure and discharge sides of the valve. The valve I42 is pro- 'vided with an additional conduit I12 whereby fluid pressure may at times be admitted to the bottom end of the spool I62 for positively lifting the valve regardless of the pressure in the conduit I44.

For the purpose of providing a controlled acceleration and deceleration of the motor, the pump 96 is provided with a swinging yoke I14 the motion of which is limited by adjustable stops I16 and I18. A- link I80 cohnects the yoke I14 to the stem I82 of a piston I84 reciprocable in a cylinder I86. A branch conduit I88 extends from the pressure line I04 through a check valve I90 to the rod end of the cylinder I86. A branch I92 extends to a port I94 of a solenoid operated three-way pilot valve I96. A port I98 connects by a conduit 200 to the head end of the cylinder I86 and by a branch 202 to the control con-- duit I12 of the valve I42. A spool 204 of the valve I96 is urged downwardly by a spring 206 but may be lifted by a solenoid E. The spool is provided with a central bore 208 which connects between port I98 and an exhaust port 2I0 when the spool is in its lower position. A circumferential groove 2I2 connects the ports I94 and I98 when the spool is in its raised position.

In operation of the hydraulic circuit shown in Fig. 2, the pump 96 is operated at constant speed and fluid is delivered to pipe I04 at varying rates depending upon the position of the yoke I14. When the yoke is in its downward positionagainst stop I16, the pump is in maximum stroke position and when-it is raised up to the stop I18, the pump is in minimum stroke position which may be very near to its position of zero stroke. If it is desired to operate the motor I02 forwardly with a predetermined acceleration, the solenoids B, D, and E are energized. The spool of the valve I96 is thus liftmi admitting pressure fluid through conduit I 88, check valve I90, conduit I92, ports I94 and I98, and conduit 200 to the head end of cylinder I86. Due to the greater area at this end of the cylinder, the pressure is able to overcome the force constantly exerted in the rod end of the cylinder and to force yoke I14 downwardly at a speed determined by the resistance of the conduits I88, I92 and 200. 'Energization of the solenoid E also admits fluid-to conduit I12 of the valve I42 causing the spool I62 to lift and open communication between conduits I44 and I40. With solenoid B energized, spool I56 is lifted, connecting port I28 to port I34,-

and port I38 to exhaust port I52. With solenoid D energized spool I54 is lifted connecting port I06 with port I24.

.Fluid is accordingly withdrawn by the pump 96 from the sump through conduit II 8 and delivered through conduit I04, port I06, port I24, conduit I26 and branch conduit I32 to motor 98. Fluid returns from the motor 98 through conduit I44, valve I42, conduit I40, port I38, port I52 to the sump. The motor 98 is thus caused to operate at a speed which increases proportionally to the movement of yoke I14 downwardly until, when the latter reaches the stop I16, the motor 98 is operating at full speed and continues to so operate so long as the solenoid E is energized and neither solenoid A or C is energized. It will be noted .that under these conditions the pressure line between the pump'and the motor is connected to the relief valve II6 from conduit I26 through port I28, port- I34 and conduit I36.

- and connecting the head end of cylinder I86 to system including conduits I32 and I04.

, mum speed is reached when the yoke I14 prevents fluid pressure the sump through conduit 200, port I98, bore 208 and port 2I0. The pressure constantly exerted in the rod end of cylinder I86 is then able to lift piston, returning yoke I14 to its minimum [stroke position at a rate determined by the resistance of the conduit I88. Shifting of the spool 204 alsov exhausts fluid from under the spool I62 of valve I42 so that the latter tends to close until sufliclent pressure is built up in conduit I44 to overcome the force of spring I66. The valve I42 is preferably adjusted so that the pressure in conduit I44 required to open the same under these conditions is comparatively small but sufllcient to create a back pressure not only in pipe I44 but also in the pressure side of the It is thus insured that 'pressure is available in the branch conduit I88 even though the load which is connected to shaft I02 may tend to overhaul the motor 98. The motor 98 is thus caused to slow down at a predetermined rate until its ministrikes the abutment I18.

Thereafter if it is desired to stop the motor 98, the solenoid A may be energized shifting the spool I56 downwardly. This connects the return conduit I40 through ports I38 and I34, and conduit I36 to the relief valve H6. The motor is thus caused to stop almost instantly because of the high pressure required to force fluid through the relief valve II6. Thus the valve II6, which during forward operation functioned merely as a safety valve on the pressure side of the system, is now connected to the return side in such a manner as to act as a brake on the motor 88. The shifting of the spool I56 also connects port I28 to exhaust port I thus bypassing the, pump 96 through conduit I04, ports I06 and I24, conduit I26, ports I28 and I50. Check valve II2 built up in conduit I36 from reaching the sump through conduit II4 under these conditions.

If it is desired to operate the motor reversely, solenoids A and C may be energized thus shifting both spools I54 and I56 to their lower position. Under these conditions fluid is delivered from the pump 96 throughoonduit I04, branch IIO, check valve II2, conduit II4, relief valve II6, conduit I36, port I34, port I38, conduit I40, check valve I43, and conduit I44 to the motor 98. Fluid expelled by-the motor is delivered through conduit 'I32, conduit I26, port I28, and port I50 to the sump. The solenoid E may be energized concurrently with energization of the solenoids Aand C although for operation of the strip feeding device disclosed in Fig. 1 it is never I necessary or desirable to drive the pinch rolls backwardly beyond the minimum reeling speed. It will be noted that during reverse operation the relief valve II6 remains in communication with the high pressure side of the circuit through branch conduit II4. To stop reverse motion of the motor 98, solenoids A and D are energized causing stoppage in the manner'previously described, except that no braking effect is produced.

For the purpose of automatically controlling energization of solenoids A, B, C, D, and E the control panel 52 is provided which is illustrated diagrammatically in Fig. 3. The timing mechateeth thereof.

nism which is driven from the worm 54 includes a timer shaft 2I3, upon which a ratchet wheel .2 is rigidly secured so that the latter turns clockwise whenever the pinch rolls are operated in a forward direction; that is, to feed the strip 30 into the press. Freely rotatable on the timershaft 2I3 behind wheel 2I4 is an arm '2I6 carrying a pivoted pawl 2I8 which is snap-acting by means of an over-center spring 220. The arm 2I6 also carries an upstanding cam surface 222 for operation of certain switch levers later to be described. the pawl 2I8 has been snapped over to its counterclockwise position by means of a fixed pin 224 which projects from the front wall of the timer mechanism into the path of the tail portion 225 of the pawl 2I8. A spiral spring 226 constantly urges the lever 2I6 into the position shown in Fig. 3. The spring 226 may be overcome by operation of the ratchet wheel 2 I4 in a clockwise direction when pawl 2I8 is engaged with the Freely rotatable on the timer shaft 2I3 on the near side of the wheel 2I4 are two adjustable arms 228 and 230 upon which the adjustable pointers 56 and 58 are carried. The arm '228 carries a normally open switch 232 which is adapted to lie in the path of thetail 225 of the pawl 2I8 whereby the switch may be closed when arm 2I6 has been carried around to the arm 228. and whereby also the pawl 2I6 may be snapped over to disengage the pawl from the ratchet wheel 2I4. The arm 230 carries a normally closed switch 234 having an operat- In the position shown in Fig. 3

ing arm 236 engageable by the 'cam.222 after a predetermined arc of movement of the arm 2I6. Mounted on a stationary part of the mechanism is a normally open switch 238 having an operating arm 239 adapted to be engaged by the cam. 222 to close the switch when the arm 2I6 is in the normal or starting position shown in Fig. 3

The two sides of an electric supply circuit are indicated at 240 and 242. The line 242 is connected by a conductor 244 to one side of each of the solenoids A, B, C, D and E. The line 240 is connected by a conductor 246 to the arm of the toggle switch 62. When the switch 62 is in its upper position; that is, the position for cyclic operation, the line 246 isconnected to conductors 248, 250 and 252. Conductor 248 leads to the arm of toggle switch 64 which is shiftable for press initiated or hand initiated cycles. In its left-hand position in Fig. 3, the switch 64 connects conductor 248 to a conductor 254 leading to the switch 68 from which a conductor 256 leads to one side of the switch 238. In its righthand position the switch 64 connects conductor 248 to a conductor 258 leading to push button switch 60, the opposite side of which is connected to the conductor 256. Switch 238 is also connected by a conductor 260 to one side of solenoid B. The conductor 250 extends to' one side of the switch 234, the opposite side of which is connected by conductor 262 to solenoid E. The conductor 252 extends to the solenoid D and has a branch conductor 264 extending to one side of the switch 232, .the opposite side of which is connected by a conductor 266 to the solenoid A.

When the switch 62 is in its lower position, that is, the position for inching operation, conductor 246 is connected'to conducto-rs268 and 210. Conductor 268 extends to a switch 212, the other side a pair of conductors 288 and 2%. Conductor 2 88..

by cam 282 before either switch 2% or switch 285 is closed. When switch 28% is closed, connection is established with the line 240 through conductor 255,2switch t2, and conductor 2m with connects to conductor 21E leading to conductor 252 and solenoid D. Conductor 29!! connects with conductor 260 and solenoid B. When switch 285 is closed, a line connection is established from conductor 21:! to conductor 215 and to a conductor 292 which connects with solenoid C.

A pair of conventional motor starting contr'ollers 295 and 296 are connected in parallel across the lines 258 and 262- by conductors 29B and 300. The controllers 29d and 295 may be of the magnetically operable type having starting push buttons 302 and 366 which energize the magnetic operating mechanism, and stop push buttons 30% and 308 which break the holding circuit for the magnetic operating mechanism. The three-way limit switch 96 is connected to the starting controller 2% in a manner to break the holding circuit when the lever 52 is moved clockwise by contact with the strip material and to make the starting magnet circuit when the lever 92 returns to normal position.

-In operation of the device as a whole a reel of material 8i may be placed on the cradle rolls i6 and 82 between the side flanges l4 and the end of the material fed through the straightening rolls 26 and the pinch rolls 32. With the switch 62 in inching position, lever $6 may be operated to the left opening switches 212 and 215 and closing switch 28%. Solenoids B and D are there by energized, the circuit for the solenoid B being from line 250, conductor 2&6, switch 62, conductor 270, switch 28%, conductors 290 and 263 through solenoid B and conductor 24% tothe return line 252. The circuit for solenoid D is the same as far as switch 285 and thence by conductors 288 and 252 through solenoid D and conductor 28% to the line 252. With solenoids B and D energized the motor I02 is caused to operate in a forward direction at minimum speed as previously described, driving the pinch rolls 32 and feeding the strip into the press.

When it is desired to stop the forward motion of the strip 30, lever 66 may be moved tomidposition, opening switch 284 and closing switches 212 and 2'18. Solenoids A and D are thereby energized, the circuit for solenoid A being through conductor 256, switch 62, conductor 27%, switch 2'26 and conductor 2T8 through solenoid A, and conductor 2% to the line 2652. The circuit for solenoid D is from switch 52 through conductor 268, switch 272, conductors 21d and 252 through solenoid D and conductor 2% to line 2&2. With the solenoids A and D energized the motor is caused to stop.

If the strip 38 has been fed too far before stopping, the lever 66 may be moved to the right opening switches 212 and 215 and closing switch 285. Solenoids A and C are thereby energized, the circuit for solenoid A being from line 250 through conductor 2616, switch 62, conductor 2'), switch 286, conductor 218, solenoid A, and conductor 2 to the line 242. The circuit for solenoid C is the same as far as switch 286 and thence through conductor 292, solenoid C and conductor 2 to the line 262. The motor 98 is thereby caused to operate reversely at a minimum speed until the lever 66 is again returned to mid-position when the motor is stopped as previously described.

If it is desired to feed the strip 30 into the press in an automatic cycle of predetermined length, the toggle switch 62 is shifted upwardly I in Fig. 3 and with the switch 64 in its righthand or hand-initiation position, the push button 60 may be depressed to causes. cycle of automatic operation. With arm 2H8 inits starting position, as shown in Fig. 3, closing of switch 60 energizes solenoid B from line 240 through conductor 246, switch 62, conductor 248, switch 34, conductor 258, switch 60, conductor 258, switch 238, conductor 260, solenoid B and conductor 2 to line 2&2. The solenoid D is energized from line 240 through conductor 246, switch 62, conductor 252, solenoid D and conductor 2 to line 252. The solenoid E is energized from line 2 through conductor 265, switch 62, conductor 250, switch 235, conductor 262, solenoid E and conductor 245 to line 242. The motor 38 is thereby caused to operate forwardly with a predetermined acceleration as previously described thus causing the strip 39 to feed into the press at a gradually increasing rate of speed. As the feed rolls 32.3

sibly even before this speed is reached, cam 222 3 engages arm 236 opening switch 236 and deenergizing the solenoid E. The motor 98 is thereby caused to decelerate, slowing down the strip 38 in its forward movement into the press. At about the time that minimum speed is reached, the arm 2E6 reaches a position where the tall 225 of pawl 2l8 abuts the switch 232, closing the same andsnapping the pawl 2E3 out of engagement with the ratchet wheel 2%. Closure of switch 232 energizes solenoid A from line 2 through conductor 2%, switch $2, conductors 252 and 264, switch 232, conductor 266, solenoid A and conductor 2 to the line 242. The solenoid D remaining energized, the motor 98 is thereby brought 'to a, quick stop through the braking 51 action previously described. The spring 226 in the meantime returns arm M6 to starting position and the mechanism is ready for a second operation whenever the push button 60 is depressed. Y

For automatic press-initiated operation of the feeding device, switch 64 is shifted to its lefthand position in Fig. 3 and reel driving motor 56 is started. The variable speed transmission 88 is adjusted to a speed somewhat greater than the average speed of the strip 38 through the device 26 and before the press it is started, the unreeling device will operate to unreel the strip 30 until the switch 92 is contacted, thus stopping'the' motor 5b. Thereafter the press Hi may be started and as theslide It returns on its upward stroke, cam 50 trips the switch 58 which initiates a cycle of operation in exactly the same manner as was initiated by manual operation of the switch various sets of dies in the press Ill, it is necesiary that the vlength of strip which is fed at one cycle may be conveniently adjusted. This is provided by the adjustable arms 228 and 238 which are operable from the front of the control panel 52 by setting the pointers 56 and 58. The two pointers 56 and 58 are preferably kept a fixed distance apart which distance is such that the deceleration of motor 98 is just completed at the time the pawl 2|! closes the switch 232. This distance should of course be varied whenever adjustments, are made at the stops I16 and I18, re-

quiring a greater or less-time for the yoke I'll.

to swing between the stops.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope" of the claims which follow.

What is claimed is as follows:

1. In a device for feeding reeled material in intermittent steps the combination of a reel, means including a pair of pinch rolls for feeding the unwound material, a hydraulic transmission for driving said means, and means for control ling the speed ratio of the transmission to initiate a cycle of operation includinga period of predetermined acceleration, and a period of predetermined deceleration followed by a stop when a predetermined length of material-has been fed.

2. In a device for feeding reeled material in intermittent steps the combination of a reel, means for driving the reel to unwind the material at a constantspeed, a pair of pinch rolls for feeding the unwound material, said pinch rolls being spaced from the reel, a hydraulic trn for driving the pinch rolls, means for controlling the speed ratio of the transmission to initiate a cycle of operation including a period of predetermined acceleration, and a period of predetermined deceleration followed rolls.

" by a stop when a predetermined length of mate rial has been fed, and means responsiveto the slack in the material between the reel and the pinch rolls for controlling the speed of the reel.

3. In a device for feeding reeled material in intermittent steps the combination of a reel,

means including a pair of pinch rolls for feeding the unwound material, a hydraulic transmission including a pump and a motor, one of which includes means for varying the displacement thereof, and means for operating said last means in a predetermined cycle for producing asprecisely controlled acceleration and deceleration of the material to feed a controlled amount thereof through the pinch rolls. v

4. In a device for feeding reeled material in intermittent steps the combination of a reel, means including a pair of pinch rolls for feeding the unwound material, a hydraulic transmission including a pump and a motor, one of which includes means including a second fluid motor for varying the displacement thereof, and valve means for operating said last means in 'a predetermined cycle for producing a precisely controlled acceleration and deceleration of the material to feed a controlled amount thereof through .the pin'ch rolls.

5. In a device for feeding strip material in inpinch rolls, a hydraulic transmission including a pump and a motor, one of which includes means for varying the displacement thereof, and means for operating said means in a predetermined eycle for producing a precisely controlled acceleration and deceleration of the material to feed a controlled amount thereof through the pinch mars '1'. HARRINGTON. L RAYMOND 'I'WYMAN. JAMES nonmson.

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