US2425496A - Winder drive - Google Patents

Description

Patente d Aug. 12, 1947 WINDER DRIVE Ransom Tyler, Greenfield, Wis., asslgnor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application October 16, 1944, Serial No. 558,843

7 Claims. (01.. 242-45) 4 1 l This invention relates to hydraulic drives and more particularly to a drive of the type employed to drive a winding machine which winds sheet or strip material into a roll as fast as it is delivered thereto from a mill or other machine.

Winder drives now in use maintain tension upon the sheet or strip during the winding operation and some of them are capable of maintaining the tension within reasonable limits after the mill and the winder have been brought up to running speed but during acceleration and deceleration. the tension varies through a wide range. A substantial variation in the tension exerted upon a thin metal strip or metal foil is very objectionable as it tends to cause a variation in the gage of the metal.

One object of the invention is to provide a winder drive which will exert tension upon the sheet or strip before the winding operation begins and will maintain a substantially uniform tension upon the sheet or strip during the winding operation.

Another object is to provide a winder-drive which will exert tension upon the sheet or strip and will maintain the tension within closer limits than was heretofore possible during acceleration and deceleration of the sheet or strip.

Other objects and advantagesof the invention will appear from the following description of an embodiment of the invention which is shown schematically in the accompanying drawing.

For the purpose of illustration, the drive has been shown as being employed to drive a winding machine which is adapted to .wind sheet material into a roll as fast as it issues from a mill or other machine. Since neither machine forms any part of the present invention, the winding machine has been represented by a winding shaft I on which the sheet is to be wound and the mill has been represented by a pair of delivery rolls 22 between which the sheet passes.

The drive includes a variable displacement hydraulic motor 3, which is adapted to drive winding shaft I through a suitable .driving connection 4, and apump 5 which is driven from delivery rolls 2 through a suitable driving connection 6. Motor 3 and pump 5 are hydraulically connected to each other by two channels I and 8 which form therewith a closed hydraulic circult, channel I having arranged therein a check valve 9 which permits liquid to flow freely from, the outlet of pump 5 to the inlet of motor 3 but prevents liquid from entering the outlet of pump 5. Channels 1 and 8 may be'connected to each.

2 other through a normally closed manually op erable valve l0.

The drivealso includes an auxiliary pump [5 which is continuously driven by an electric motor I6. Pump l5 draws. liquid from a reservoir l1 and discharges it into a branched supply channel l8 one branch of whichis connected to channel 1 to enable pump l5 to make up leakage losses in the main hydraulic circuit and to maintain pressure in channel 1 during the winding operation at which time a part of the liquid discharged by.

' I1 and to the intake of pump l5.

When the drive is idle, pump l5 v is bypassed through a valve 23 having a piston 24 fitted in its casing 25 andnormally held in a bypass position by a spring 26. A branch of channel I8 is connected to casing 25 adjacent the normal position of piston 24 and both ends of casing 25 are connected by a channel 21 to return channel 22. The arrangement is such that, when valve 23 is open, all the liquid discharged by pump I5 flows through channel It, valve 23, channel 21 and channel 22 tothe intake of pump l5 and, when valve 23 is closed, the liquid discharged by pump I5 is directed to channel I and to motor l9.

Valve 23 may be operated manually or in any suitable manner but it is ordinarily closed by a solenoid 28 the armature of which is connected to the stem of piston 24. Solenoid 28 is controlled by a switch such as a push button switch 29 arranged in a control panel 30.

When valve 23 is closed, the pressure that can be created by pumpv i5 is limited by a safety valve 3| which in practice is built ,into pump l5 but which for the purpose of :illustration has been shown connected between channel l8 andreservoir I'I.

Hydraulic motor 3 has a displacement varying member or slide block 35 which is shiftable toward and from a minimum displacement position to vary the speed of motor 3 relative to the rate at which motive liquid is delivered thereto. Slide block 3545 adapted to be moved toward its maximum displacement position by a servo-motor having a piston 36 fltted in a stationary cylinder 31 carried by the pump casing on one side thereof, and it is adapted to be moved toward its minimum displacement position by a servo-motor having a piston 38 fitted in a stationary cylinder 39 carried by the pump casing on the other side thereof. The maximum displacement position of slide block 35 is determined by an adjusting screw 43 threaded through the head of cylinder 38 to enthereof according to the usual practice but which for the purpose of illustration has been shown as a separate pump and as drawing liquid from reservoir II andldischarging it into channel 42. Liquid discharged by gear pump 43 in excess of requirements is exhausted through a relief valve 44 which'enables gear pump 43 to maintain a, constant pressure in cylinder 31 so that piston 36 is enabled to exert a constant force upon slide block 35.

Slide block 35 is adapted to be shifted in one direction or the other in response to a Variation in the flow in channel 8 relative to the flow in channel I. In'order that this may be accomplished, cylinder 33 is connected to channel 8 by a channel and channel 8 is connected to reservoir II by achannel 48 having arranged therein aresistance valve 41 which, if pistons 36 and 38 have the same effective pressure areas. will open at a pressure somewhat higher than gear pump pressure.

The arrangement is such that, when motor 3 discharges more liquid into channel 3 than can enter pump 5, the excess liquid will flow through channel 45 to cylinder 39 and cause piston 38 to move slide block 35 in a direction to decrease the displacement of motor 3. Piston 35 will move-with slide block 35 and eject liquid from cylinder 31 through channel 42 and relief valve 44 into reservoir I'I. After piston 35 engages adjusting screw 4| and stops further movement of slide block 35, any liquid discharged by motor 3 in excess of the liquid that can enter pump is exhausted through resistance valve 41 and channel 45 into reservoir iI. When pump 5 attempts to draw more liquid from channel 3 than is discharged into it by motor 3, the pressure in channel 3 and in cylinder 33 will drop and permit the gear pump liquid to move piston 33 and slide block 35 in a direction to increase the displacement of motor 3.

If desired, means may be provided for causing the mill or other machine to start immediately after the end of the sheet has been attached to winding shaft I and the slack has been pulled out of the sheet. For example, the mill or other machine may be caused to start in response to the closing of a switch 50 which closes in respons to the creation of a predetermined pressure in channel I. As shown, switch 53 is adapted to be closed by a piston 5i .fltted in a stationary cylinder 52 which is connected to channel I b a channel 53. Piston 5! is urged to its inoperative position by a spring 54 the tension of which may be adjusted by a nut 55 to a value great enough to prevent piston 5! from closing switch 53 until the sheet becomes taut.

Operation Assuming thatthe parts are in the positions shown, that pump I5 is running,'that the mill is idle and that enough of the sheet extends beyond rolls 2 to permit the end thereof to be 5 is idle and pump I5 is being bypassed through son with pump I5 and arranged in the casing valve 23. The operator will first attach the end of the sheet to winding shaft I with as little slack in the sheet as possible. and then he will close bypass valve 23 if it is manually operable or he will close a switch, such as switch 23, to cause valve 23 to close if it is electrically controlled.

With valve 23 closed, the liquid discharged by pump I5 must flow either through channel M to motor I3 or through channels I8 and i to 'motor 3 since check valve 3 prevents the liquid from entering pump 5. The inertia of flywheel resists rotation of motor I3 and tension control valve 2| resists the discharge of liquid from motor I3 which causes pump I5 to create suflicient pressure to enable the liquid to start motor 3 which will rotate winding shaft I to pull the sheet taut and exert tension thereon.

Since there is only a little slack in the sheet, motor 3 needs to rotate but little to pull the slack out of the sheet. As soon as motor 3 starts to rotate, it discharges liquid into channel 8 and, since pump 5 is idle at this time so that the liquid cannot enter it. the liquid flows through channel 45 to cylinder 33 and causes piston 38 to reduce the displacement of motor 3. However, the pressure required to start and accelerate motor I 3 is great enough to enable motor 3 to start the winding machine and cause it to exert tension upon the sheet even when motor 3 is at its minimum displacement as determined by the adjustment of screw 4i. termined tension is exerted upon the sheet, motor 3 will stop and maintain that tension .unless the mill is started the instant that the sheet becomes taut.

Operators of winding machines are ordinarily highly skilled and able to operate the mill starting mechanism just as or just before the sheet becomes taut but, if desired, the mill ma be started automatically in any suitable manner such as by means of switch 53. If switch 53 is employed, motor 3 will stop when the sheet becomes taut and then all of the-liquid discharged by pum I5 will tend to flow through motor 18 but, since flywheel 23 can not be accelerated to full speed instantly, pump 95 must increase the pressure until it is high enough to open safety valve 3| and then the excess liquid will flow therethrough to reservoir II. The increased pressure will extend through channels I8, I and 53 to cylinder 52 and cause piston 5| to close switch 5|] and thereby cause the mill to start.

Starting the mill either manually or automatically causes rolls 2 to deliver the sheet to shaft l and to drive pump 5 which will discharge liquid into channel I and draw liquid from channel 8 at a rate proportional to the rate at which the sheet is delivered to shaft I.

The liquid discharged into channel I by pumps 5 and I5 will energize motor 3 which will rotate shaft I to wind the sheet thereon and to main-' When a prededisplacement of motor 3 until it did have suflicient torque as previously explained The mill will gradually accelerate to full speed and rolls 2 will gradually increase the speed of the sheet. Pump will accelerate in unison with rolls 2 and increase its rate of delivery in proportion to the increase in the speed of the sheet. This increase in delivery will accelerate motor 3 which will accelerate shaft I to wind the sheet thereon as fast as it is delivered thereto. Since pump i5 delivers liquid to motor 3 in addition to the liquid delivered thereto by pump 5, motor 3 tends to run faster than the rate determined by the rate at which pump 5 delivers liquid there! to which rate is proportional to the speed of the sheet. Consequently, motor 3 maintains tension upon the sheet.

The parts are so proportioned that flywheel reaches full speed at approximately the same time that the mill reaches full speed. Thereafter, all of the liquid discharged by pump ili passes through motor i9 and tension control valve 2| except a small portion required to make up for leakage losses and to maintain pressure in channel 'I so that the pressure in channel 1 is determined by the resistance of valve 2|, The tension exerted upon the sheet is dependent upon the torque of motor 3 which is dependent upon the pressure in channel I. Therefore, the tension is determined by valve 2| which may be adjusted to vary the tension.

As the sheet accumulates upon shaft I, the peripheral speed of the roll of sheet material on shaft i will remain the same as the linear speed of the sheet but the rotary speed of shaft I will decrease due to the increase in the diameter of the roll of sheet material. Decreasing the speed ofshaft i causes motor 3 to slow down and tend to deliver less liquid into channel 8 than is drawn therefrom by pump 5 so that the pressure in channel 8 and in cylinder 39 drops and permits servo-motor 36-31 to increase the displacement of motor 3 and thereby increase the rate of motor discharge relative to the rate of motor speed so that the pressure inchannel 3 and in cylinder 39 is prevented from'decreasing. The gradual increase in the diameter of the roll of material on shaft I thus causes motor 3 to gradually increase its displacement and its torque so that it maintains a constant tension on the sheet during the winding operation.

The winder drive described herein is susceptible of various modifications and adaptations without departing from the scope of the invention which is hereby claimed as follows:

1. In a mechanism having rolls for delivering strip material and a winder roll for winding said strip material thereon as fast as it is delivered by said rolls, the combination of a variable displacement hydraulic motor connected to said winder roll to drive the same, a main pump driven in unison with said delivery rolls for delivering motive liquid to said motor to energize the same, fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides, a relatively small pump driven independently of said main pump and connected to the pressure side of said -circuit to supply additional liquid thereto and thereby enable said motor to exert tension upon said strip material when said delivery rolls and'said main pump are idle, and a bypass for theescape of liquid discharged by said small ump in excess of the liquidrequired by said motor, said bypass including means pro- 6 viding a gradually decreasing resistance to the flow through said bypass to thereby enable said small pump to create a pressure which is initially maximum and decreases to a predetermined minimum during continued flow through said by- I and said motor and forming therewith a hydrau lic circuit having pressure and return sides, a relatively small pump driven independently of said main pump and connected to the pressure side of said circuit to supply additional liquid thereto and thereby enable said motor to exert tension upon said strip material when said delivery rolls and said main pump are idle, and a bypass for the escape of liquid discharged by said small pump in excess of the liquid required by said motor, said bypass including a substantially constant resistance and means which provides a gradually decreasing resistance to the flow of liquid through said bypass and which coacts with said constant resistance to enable motive liquid to said motor to energize the same,

fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides, a relatively small pump driven independently of said main pump and connected to the pressure sideof said circuit to supply additional liquid thereto and thereby enable said motor to exert tension upon said strip material when said delivery rolls and said main pump are idle, a bypass for the es-.

cape of liquid discharged by said small pump in excess of the liquid required by said motor, said bypass including a substantially constant resistance and means which provides a gradually decreasing resistance to the flow of liquid through said bypass and which coacts with said con-.

stant resistance to enable said small pump to create a pressure which is initially maximum and gradually decreases to a predetermined minimum during continued flow through said bypass means responsive to an increase in pressure in the return side of said circuit for reducing the displacement of said motor, and a relief valve providing escape of liquid from the return side of said circuit in response to the pressure therein reaching a given maximum.

4. [In a mechanism having rolls for delivering strip material and a winder roll for winding said strip material thereon as fast as it is delivered by said rolls, the combination of a variable displacement hydraulic motor connected to said winder roll to drive the same, a main pump driven in unison with said delivery rolls for de-.

livering motive liquid to said motor to energize the same, fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides,

I motor to resist the flow of liquid therethrough,

and a valve adapted when open to bypass said auxiliary pump and adapted when closed to cause the liquid discharged by said auxiliary pump to tend to start said auxiliary motor and to create pressure in the pressure side of said circuit to thereby enable said variable displacement motor 'to start before said main pump starts.

5. In a mechanism having rolls for delivering strip material and a winder roll for winding said strip material thereon as fast as it is delivered by said rolls, the combination of a variable displacement hydraulic motor connected to said winder roll to drive the same, a main pump driven in unison with said delivery rolls for delivering motive liquid to said motor to energize the same, fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides, an auxiliary motor, a flywheel driven by said auxiliary motor, an independently driven auxiliary pump connected to said auxiliary motor and to the pressure side. of said circuit. a tension control valve connected in series with said auxiliary motor to resist the flow of liquid therethrough,

a valve adapted when open to bypass said auxiliary pump and adapted when closed to cause the liquid discharged by said auxiliary pump to I tend to start said auxiliary motor and to create pressure in the pressure side of said circuit to thereby enable said variable displacement motor .to start before saidmain pump starts, and a check valve arranged in the pressure side of said circuit adjacent said main pump to prevent liquid delivered by said auxiliar vpump from entering said main pump.

' 6. In a mechanism having rolls for delivering strip material and a winder roll for winding said strip material thereon as fast as it is delivered by said rolls, the combination of a variable displacement hydraulic motor connected to said winder roll to drive the same, a main pump 8 driven in unison with said delivery rolls for delivering motive liquid to said motor to energize the same, fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides, an auxiliary motor. a flywheel driven by said auxiliary motor, an independently driven auxiliary pump connected to said auxiliary motor and to the pressure side of said circuit, a tension control valve connected in series with said auxiliary mo-' tor to resist the flow of liquid therethrough, a valve adapted when open to bypass said auxiliary pump and adapted when closed to cause the liquid discharged by said auxiliary pump to tend to start said auxiliary motor and to create pressure in the'pressure side of said circuit to thereby enable-said variable displacement motor to start before said main p mp starts, and means responsive to a variation in the pressure in the return side of said circuit for varying the dislacement of said motor.

'7. In a mechanism having rolls 'for delivering strip material, means for starting said rolls and a winder roll for winding said strip material thereon as fast asit is delivered by said rolls, the

combination of a hydraulic motorrconnected to said winder roll to drive the same. a pump drivenv in unison with said delivery rolls for delivering motive liquid to said motor to energize the same, fluid channels connecting said pump and said motor and forming therewith a hydraulic circuit having pressure and return sides. means for supplying additional liquid to the pressure side of said circuit, and means responsive to the pressure in said circuit-reaching a predetermined maximumior effecting operation or RANSOM TYLER.

said roll starting means.

REFERENCES crrm' The following references are oi record in the file of this patent:

UNITED STATES PATENTS Number v i Name Date 2,232,317 Douglas Feb. 18, 1941 2,351,264 Harrington et al. June 13,1944 2.354.278 Robinson July 25. was

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