US3771703A

US3771703A - Hydraulic rotary strip stock feeder

Info

Publication number: US3771703A
Application number: US00230353A
Authority: US
Inventors: A Denis
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-02-29
Filing date: 1972-02-29
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13
Also published as: GB1422869A; AU475571B2; AU5266673A; NL7302693A; DE2309466A1; AR201737A1; BR7301439D0; IT979545B; BE796124A; ZA731332B; JPS4899779A; SE393949B; CA963358A; FR2174615A5

Abstract

An improvement is described in strip stock feeders of the type in which a coiled metal strip is uncoiled and advanced by pressure rollers. The invention concerns a hydraulic drive system for the rollers in which a hydraulic motor is powered by a hydraulic pump via a conduit system. This system includes two parallel flow paths which permit different amounts of fluid to pass through the motor, thereby operating the motor at different speeds. Controllable valves determined which paths the fluid follows or stop all fluid flow through the system thereby stopping the motor.

Description

United States Pat'en 19] St. Denis I y NOV. 13, 1973 i 1 HYDRAULIC ROTARY STRIP STOCK FEEDER [76] Inventor: Andrew R. St. Denis, 3541 Rankin Ave., Windsor, Ontario, Canada [22] Filed: Feb. 29, 1972 [21] Appl. No.: 230,353

[52] US. Cl 226/42, 226/122, 226/181 [51] Int. Cl B65h 23/22 [58] Field of Search 226/122, 181, 42,

[56] References Cited UNITED STATES PATENTS 3,362,601 1/1968 Ford et a1. 226/122 Primary Examiner-Allen N. Knowles Assistant ExaminerGene A. Church Attorney-Peter Kirby et a1.

[5 7] ABSTRACT An improvement is described in strip stock feeders of the type in which a coiled metal strip is uncoiled and advanced by pressure rollers. The invention concerns a hydraulic drive system for the rollers in which a hydraulic motor is powered by a hydraulic pump via a conduit system. This system includes two parallel flow paths which permit different amounts of fluid to pass through the motor, thereby operating the motor at different speeds. Controllable valves determined which paths the fluid follows or stop all fluid flow through the system thereby stopping the motor.

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HYDRAULIC ROTARY STRIP STOCK FEEDER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a device for intermittently advancing predetermined lengths of strip material, e.g., advancing strip metal stock to power presses.

2. Description of Prior Art Strip metal, usually steel, from which shapes are to be cut by power presses is supplied in tightly wound coils, the outside diameters of which may be as much as 4 feet or more. While the metal of a coil usually is annealed, it nevertheless is quite stiff and is set in the curvature of the coil. As a result, it is necessary to pass the strip through a straightening mechanism which usually comprises a series of rollers that progressively reduce the curvature.

The coil to be unwound is usually supported in a cradle which carries the coil either on rotatable members that project axially into the center of the coil or rollers which lie beneath'the coil and are engaged by the periphery of the coil. The rotatable members or the rollers in some installations are permitted to turn as the coil is unwound by pulling the strip metal therefrom. In other installations at least one of the rotatable members or the rollers may be motor driven to turn the coil.

Because the metal of the strip is set in the curvature of the coil, the portion of the strip being unwound must be' forcefully pulled away from the remainder of the coil against the resistance of the strip against unwinding and also the resistance created by the weight of the coil supported in the cradle. Moreover, further resistance is usually met in terms of the force required to pull the unwound strip through a series of straightening rollers to straighten the strip. All of the above resistances must be overcome by the mechanismwhich pulls the metal strip away from the coil and feeds it to a power press.

It has been the usual practice to employ powered rollers between which the metal strip passes for uncoiling the strip and feeding it to a power press. However, even when very high pressures are applied to-these powered feed rollers, there does tend'to'be from time to time slippage because of variations in the guage of the metal, contaminants on the surface, etc. If sufficient of the metal-strip is not moved forwardly by the feed rollers during the cycle of the power press, the press will not receive sufficient metal in the next cycle so that the workpiece is ruined. One system that has been utilized in the past for overcoming this difficulty hasbeen to set the feeder a considerable distance away from the power press and then leavea slack loop in the metal so that there will be some leeway and the press will be assured of having sufficient metal in every cycle. Such a system, of course, requires an attentive operator who will actuate the, feeder to guarantee than sufficient slack is maintained in the strip metal between the feeder and the press and this, means that the machine is not fully automatic. i I

The above system assures that there is sufficient material supplied to the press but there is also. the-difficulty of supplying only sufficient material and no more. In other words, it is usually necessary to allow for inaccuracies in such a system and, to be assured that there will be sufficient material, it has been the usual practice to allow a slight excess beyond that required for punchparts are being punched from strip metal, this waste becomes a very significant factor in production costs.

There is, therefore, a great need for a strip stock feeder which can supply a very precise amount of strip stock to a production machine such as a power press during each cycle of the machine. A device which can automatically supply a precise amount during each cycle obviously has great benefits in terms of savings in labour and material costs. It is the object of this invention to provide such a feeder system.

SUMMARY OF. THE INVENTION According to the present invention an improved device is provided for intermittently advancing predetermined lengths of strip material. The device has the usual powered feed rollers between which the strip material passes. These rollers are driven by a hydraulic motor to which hydraulic power is supplied from a hydraulic pump through a fluid conduit system. The conduit system includes two parallel flow paths, one path permitting a large flow of fluid through the hydraulic motor and the other path permitting a restricted fluid flow through the motor, thereby respectively providing high and low speed operations of the motor. Controllable valves, e.g.,'solenoid valves, are provided in the system and these are arranged'such that in a first flow position, fluid flows through the large flow path or both the large and restricted paths, in a second flow position the fluid flows through only the restricted path and in a third position the conduit system is completely closed against any fluid flow.

The valves are controlled by a measuring device which measures the length of material which has advanced through the rollers. Thus, at the start of a cycle the valves permit a large flow of fluid through the motor and it travels at a high speed. After a predetermined length of material has advanced, the one or more valves are actuated such that only the restricted and the motor abruptly stops.

The system of this invention combines the unique ad'- vantages of both high speed and accuracy. This is possible because it takes full advantage of the properties of h'ydraulic fluids. It is particularly effective when used in conjunction with a hydraulic pump of the pressure compensator type which automatically adjusts pump delivery to maintain varying volume, requirements of the system at a preselected operating pressure. With such a system, the entire advance cycle except for the final fraction of an inch can operate at high speed and as it approaches the end of the advance cycle, the sudden decrease in fluid flow through the motor quickly decreases the travel speedrTh e total final lengthis then approached at this slower speed so that when the fluid system is closed, the material stops at precisely the desired point. In this manner the length of material advanced in a cycle can be controlled-within one thousandth of an inch while' operating at highspeeds. I

Particularly with the compensator. pump, this system has been found to be most unexpectedly smooth and quiet in operation. Since the braking action is entirely within the hydraulic system, there is no pounding or vibration at the end of a cycle because of contact with abutments, etc. and also because of the very few moving parts, maintenance can be kept to an exceedingly low level.

Although the above description refers to a slow-down stage before coming to a full stop, it will be appreciated that the system could also operate with a simple bydraulic system with one valve which opened or closed the system. Of course, if the machine is to operate at high speeds, the control of the end point in a material advance cycle becomes much more difficult to control without a slow-down stage and, alternatively, the entire advance cycle can be at a slower speed.

As a measuring device for measuring the length of material advanced, there can conveniently be used a wheel which is rotated by advance of the material. This wheel can turn a rotary transducer which feeds electric signals to an electronic counter. The counter includes relays for actuating the valves ane can be adjusted whereby the different valves are actuated when the different lengths of material have passed. It can also include an automatic reset for repeating the cycle and is operatively connected to the machine receiving the advanced lengths of material, e.g., a power press, whereby the advancingcycles are synchronized with the press cycles.

According to a particularly preferred embodiment of the invention, the conduit system includes a flow line which passes from the pump through a first solenoid valve to the motor. A return line passes from the motor back through the first solenoid valve to a hydraulic fluid reservoir. In the return line are a pair of parallel paths, one permitting a full flow of fluid and the other permitting only a restricted flow. Both of the parallel paths include a solenoid valve so that either one or both can be closed. The valves in the parallel paths determine the paths to be followed by the fluid while the first valve in closed position completely seals the loop containing the motor thereby preventing movement of the motor in any direction.

Any of the normally used hydraulic fluids can be used in this system, e.g., water base fluids and petroleum oils. Because of the simplicity of the system, it is also possible to use the new synthetic, fire-resistant fluids. These may require special valve seals but such are commercially available.

Certain preferred embodiments of the invention are illustrated in the attached drawings in which:

FIG. 1 is a side elevation of an uncoiling and feeding apparatus incorporating the features of this invention;

FIG. 2 is an end elevation showing details of feed rollers;

FIG. 3 is a top plan view of the device;

FIG. 4 is an isometric view of a side plate;

FIG. 5 is a detailed plan view of straightening roller adjusters; and

FIG. 6 is a schematic illustration of the hydraulic system.

As will be seen from FIG. 1, the feeding device 10 is attached to an uncoiling device 11. It will, of course, be appreciated that the feeder 10 can be used in association with any type of uncoiler. The uncoiler in this case has a pair of heavy steel plate side walls 12 within which a coil of strip metal 13 is supported on transverse rollers 14. One or more of these rollers 14 can be powered to assist in the uncoiling of the coil. The uncoiled strip 15 comes out as a large loop and passes up to the feeder device. A burn-out 16 is provided in each side plate 12 and a shaft can be inserted into this to prevent the coil 13 from moving out of position on the support rollers 14. This becomes particularly significant close to the end of the coil when it becomes quite light.

Looking now at the feeder device, this has a support structure with side walls 17 and end walls 18. The top is in the form of a heavy steel plate 19 which forms a support table for feed rollers, straighteners, etc.

On the plate 19 are mounted a pair of spaced heavy steel plates 20 and 21. Details of plate 20 are shown in FIG. 4 from which it will be seen that a number of holes are provided. Towards the front end of plate 20 is a rectangular burn-out 22 and a smaller burn-out 23 close to the upper edge. In the space between the burnout 23 and the upper edge is a central vertical hole 24 and extending through from the upper edge to the burn-out 22 are a pair of holes 25. A circular hole 26 is provided beneath burn-out 22.

In a central portion of plate 20 is another rectangular burn-out 27 with a hole 28 beneath and towards the rear end of plate 20 are another pair of rectangular burn-

outs

29 and 30. The function of these various holes and burn-outs will be described hereinafter.

The feed rollers comprise a lower roller 31 and an upper roller 32. These extend the full width of the machine and are provided with a series of spiral grooves on the surface as illustrated.

The

rollers

31 and 32 are mounted on shafts and are operatively connected at one end by means of

gear wheels

33 and 34. The roller 31 is mounted in plates 20 and 21 in a permanent location in sealed bearings. The shaft extends through hole 26 in plate 20 and a corresponding hole in plate 21. The shaft of roller 32 is mounted in sealed bearings in sliding blocks 42 which are mounted in burn-out 22 in plate 20 and a corresponding burn-out in plate 21. The blocks 42 can slide up and downin the burn-out 22 thereby increasing or decreasing the pressure being applied by roller 32.

This pressure is controlled by means of a springloading. A threaded stud 37 is mounted in hole 24 and projects upwardly beyond the surface of plates 20 and 21. A pair of shafts or pins 38 extend down through holes and the lower ends of these pins 38 engage the block 42 for pushing it downwardly. The upper ends of these pins 38 engage -a disc 39 which slides up and down on stud 37. A spring 41 is mounted above disc 39 and above spring 41 is a second disc 40 which is threaded onto stud 37. Thus, by turning disc 40 upwardly or downwardly on stud 37, the pressure being applied to roller 32 via spring 41 can be increased or decreased.

Power is supplied to the lower roller 31 by means of a hydraulic motor which is fixed to vertical plate 21 by way of studs 36. Preferred for this purpose is a high torque low speed motor of the positive displacement, bi-directional type. Such motors typically incorporate a roll-vane geroter and commutator principle to modify displacement and torque. A particularly useful motor is a Vickers I-ITLS-l23-A.

The measuring and controlling system for determining the amount of strip material advanced includes a measuring wheel of predetermined diameter mounted on a shaft. This wheel is positioned beneath the metal strip 15 and the shaft has connected at one end thereof a photo-electric rotary transducer 43 which is connected to plate 20. The strip material contacting surface of the wheel can be coated with a plastic, such as a urethane plastic, to prevent slipping. There is a direct controller 47.

connection between the axle supporting the wheel and the transducer 43 so that the transducer will always directly respond to'any rotational movement of the measuring wheel. Directly above the measuring wheel is mounted a roller 44 and this roller is supported in sealed bearings in slide blocks 45 which are mounted within rectangular cut-outs 27. These blocks 45 are spring-biased downwardly by means of springs 46 thereby pressing the strip metal 15 into firm engagement with the measuring wheel.

The transducer 43 is connected by way of connector 48 to an electronic counter 47 mounted at a convenient location on the side of the feeder. The electronic counter has two series of preset control buttons and each control button has a series of calibrations. Each of the two series of preset buttons is arranged to activate a separate relay. The electronic counter has a typical terminal board with connections for the first and second relay outputs, signal input, external reset, etc.

Next in line behind the transducer 43 and measuring wheel are a series of lower rollers 49 and upper rollers 50. These are straightening rollers which remove the natural curvature from the strip metal 15. The lower rollers 49 are mounted in sealed bearings on the inner faces of plates 20 and 21 while the upper rollers50 are mounted in seal bearings in slide blocks 51 which are positioned within rectangular burn-

outs

29 and 30 of plate 20 and corresponding burn-outs in plate 21. These slide blocks 51 and hence the upper rollers 50 can be moved upwardly and downwardly by means of threaded shafts 52. In order that both ends of each roller 50 will always move uniformly, the end adjusting mechanisms include gear wheels 53 and connecting chains 54.

Positioned on top plate 19 adjacent the rear ends of plates 20 and 21 is a box beam 55. This beam has a slot 56 cut out of the top face andhas a pair of vertically mounted freely rotating rollers 57 positioned therein. These rollers can'be clamped at any desired position in the slot 56 and are positioned immediately on each side of the strip metal 15 thereby guiding the metal.

The hydraulic power and control system is entirely mounted within the support structure of feeder and includes a support platform 58 on which are mounted an electric motor 59 and a hydraulic pump 60. The hy-' draulic pump is preferably of the pressure compensator type which automatically adjusts pump delivery to maintain volume requirements of the system at a preselected operating pressure. A particularly suitable pump is the Vickers in-line piston pump available from Sperry Rand. v I

A forty gallon tank 61 is provided 'as'a hydraulic fluid reservoir and this is connected to pump 60 by fluid inlet line 62. The outlet line of pump 60 is connected to hydraulic motor 35 via three

solenoid valves

63, 64 and 65. These solenoid valves are controlled by means of In operation, at the start of a feeding cycle, all three solenoid valves are activated whereby a maximum flow of fluid travels from pump 60 to motor 35 and strip metal is advanced at a maximum speed. After the metal has travelled a substantial portion of its predetermined distance, the controller 47 deactivates valve 65 so that-flow continues only through valves 63 and-64. Only a restricted flow is permitted through valve 64 with the result that the deactivation of valve 65 causes an instantaneous decrease in the flow of fluid through pump 35 thereby greatly decreasing the speed of travel. When the total desired amount of material in a cycle has passedthe measuring wheel the counter 47 deactivates both

valves

63 and 64 thereby instantaneously completely stopping all flow of fluid in the conduit system. This has the effect of instantaneously stopping the feed rollers and the strip material '15. With this arrangement there is no overrun or backlash and the material stops at precisely the location demanded.

The hydraulic system will now be described in greater detail with reference to FIG. 6. As will be seen from this figure, motor 59 is connected to hydraulic pump 60 through a Magnaloy coupling 66. The inlet 62 from reservoir 61 to pump 60 includes an inlet strainer 67. A fluid return line from the pump 60 to reservoir 61 is shown as a broken line. The outlet from pump 60 passes through a balanced piston relief valve 68 and also connected to the outlet line is a shut-off valve 69 leading to a 3,000 psi range gauge. The relief valve 68 also includes a return line to the reservoir 61.

From the relief valve 68 the pump outlet line proceeds to solenoid valve 63 and this is a double solenoid with the two solenoids designated as SOL.1 and SOL.4. Using standard symbols for fluid powered diagrams, it will be seen that line connection A connects to one side of hydraulic motor 35. Connector P connects to the pump outlet line, connector T connects to a return line back to the reservoir 61 while connector B connects to a conduit 72 coming from

solenoid valves

64 and 65.

The solenoid valve 64 is a single solenoid valve containing the solenoid designated as SOL.2. This valve is connected across between conduit 73 connecting to one side of motor 35 and conduit 72 coming from valve 63. The connection across is via conduit 74. Connector P is connected to line 74 while connector T joins a conduit returning to reservoir 61. Connector A is closed off by a plug while connector B is connected to a line coming from conduit 72 and containing therein a Manatiol non-compensated flow control 70.

The solenoid valve 65 is once again a double solenoid having the two solenoids designated as SOL.3 and SOLS. This valve 65 is joined in parallel with valve 64 by conduit loop 75 with the'conduit being joined to connectors A'and P while connector B is blocked with a plug and connector T joins a return conduit to reservoir 61;

With the above arrangement it will be seen that during the rapid initial advance of the metal strip, solenoids SOLJ, SOL.2 and SOL.3 are all activated so that hydraulic fluid is being pumped from pump 60 through valve 63 to motor 35, then through both

valves

64 and 65 back through valve 63 and back to fluid reservoir 61. When the speed of travel is to slow down, solenoid SOL.3 is deactivated thereby closing conduit 75 so that a restricted flow then passes through valve 64 only and the flow controller 70. This has the effect of slowing down the speed of motor 35. When the travel is to come to a full stop all of the solenoids are deactivated and this means that all flow stops at valve 63. This provides an instantaneous stop since the conduit loop from connectors A and B of valve 63 around through the motor 35 is completely closed. In other words, there is It is to be understood that the above description is illustrative of this invention and that various modificationsthereof can be utilized without departing from its spirit and scope.

I claim:

1. A device for intermittently advancing predetermined lengths of strip metal which is being removed from a coil, said device comprising:

a. a framework supporting a heavy steel platform;

b. a pair of vertically stacked feed rollers mounted on said platform, said rollers being spring biased into contact with each other and gear connected for powered rotation,

c. a hydraulic motor operatively connected to one of said rollers,

d. a hydraulic pump mounted on said framework beneath the platform with the inlet thereof connected to a fluid reservoir mounted on the frame,

e. a conduit connecting the hydraulic pump outlet to the hydraulic motor inlet,

f. a first solenoid valve connected in said conduit,

g. conduits connecting the hydraulic motor outlet to said fluid reservoir, said conduits returning through said first solenoid valve and including between the hydraulic motor and first solenoid valve two parallel paths with a solenoid valve connected into each path, one of said paths including a flow restrictor,

h. a measuring wheel mounted on the platform on an axle parallel to the axes of the feed rollers for rolling engagement with the strip metal,

i. a rotary transducer mounted on one end of the measuring wheel axle,

j. an electronic impulse counter for counting impulses received from the transducer and including relays which activate said solenoid valves, whereby the different valves are actuated at different times depending on the length of strip metal measured by the wheel such that during an initial major portion of an advance cycle all three valves are open and fluid fiows through both parallel paths, during a final minor portion of the advance cycle one valve is closed such that fluid flows through the restricted path only and finally all three valves are closed to stop the advance cycle.

2. A device according to claim 1 wherein a series of metal strip straightening rollers are also mounted on said platform.

3. A device according to claim 2 in combination with a reel uncoiling cradle.

4. A device for intermittently advancing predetermined lengths of strip material which comprises:

a. roller means for gripping and advancing the strip material,

b. hydraulic motor connected to said roller means in a direct, mutual driving relationship,

0. hydraulic power means for supplying hydraulic power to said motor,

d. first conduit means connecting said hydraulic power means to an input port of said motor,

e. second conduit means connecting an output port of said motor to a hydraulic fluid exhaust line,

f. first valve means having an open and a closed position and being located in said first conduit means for controlling fluid flow therethrough,

g. second valve means having an open and a closed position and being located in said second conduit means, said second valve means including a valve member providing a high flow rate path and a valve member providing a restricted fiow rate path,

h. a measuring device for monitoring advancement of said material by the rollers and'for emitting a slow down signal and a stop signal under predetermined conditions, and

i. means controlled by said slow down signal for moving said high fiow rate path valve to closed position and means controlled by said stop signal for moving said restricted flow rate path valve and said first valve means to closed position.

5. A device according to claim 4 wherein the hydraulic power means is a hydraulic pump.

6. A device according to claim 5 wherein the first and second conduit means are in the form of a loop including the motor with the ends of the loop being connected through said first valve means whereby when said first valve means is in closed position no fluid flow is permitted through the motor in either forward or backward direction.

7. A device according to claim 6 wherein the restricted flow rate path contains a non-compensated flow control.

8. A device according to claim 5 wherein said second conduit means includes a pair of parallel conduits providing the high fiow rate path and the restricted flow rate path, each of said parallel conduits containing a valve member having an open and a closed position.

9. A device according to claim 4 wherein the measuring device comprises a measuring wheel rotatably connected to a rotary transducer and an electronic impulse counter, said counter activating said controllable valves.

10. A device according to claim 4 in combination with a strip metal uncoiling cradle.

11. A device according to claim 10 in combination with metal straightening rollers.

Claims

1. A device for intermittently advancing predetermined lengths of strip metal which is being removed from a coil, said device comprising: a. a framework supporting a heavy steel platform; b. a pair of vertically stacked feed rollers mounted on said platform, said rollers being spring biased into contact with each other and gear connected for powered rotation, c. a hydraulic motor operatively connected to one of said rollers, d. a hydraulic pump mounted on said framework beneath the platform with the inlet thereof connected to a fluid reservoir mounted on the frame, e. a conduit connecting the hydraulic pump outlet to the hydraulic motor inlet, f. a first solenoid valve connected in said conduit, g. conduits connecting the hydraulic motor outlet to said fluid reservoir, said conduits returning through said first solenoid valve and including between the hydraulic motor and first solenoid valve two parallel paths with a solenoid valve connected into each path, one of said paths including a flow restrictor, h. a measuring wheel mounted on the platform on an axle parallel to the axes of the feed rollers for rolling engagement with the strip metal, i. a rotary transducer mounted on one end of the measuring wheel axle, j. an electronic impulse counter for counting impulses received from the transducer and including relays which activate said solenoid valves, whereby the different valves are actuated at different times depending on the length of strip metal measured by the wheel such that during an initial major portion of an advance cycle all three valves are open and fluid flows through both parallel paths, during a final minor portion of the advance cycle one valve is closed such that fluid flows through the restricted path only and finally all three valves are closed to stop the advance cycle.

3. A device according to claim 2 in combination with a reel uncoiling cradle.

4. A device for intermittently advancing predetermined lengths of strip material which comprises: a. roller means for gripping and advancing the strip material, b. hydraulic motor connected to said roller means in a direct, mutual driving relationship, c. hydraulic power means for supplying hydraulic power to said motor, d. first conduit means connecting said hydraulic power means to an input port of said motor, e. second conduit means connecting an output port of said motor to a hydraulic fluid exhaust line, f. first valve means having an open and a closed position and being located in said first conduit means for controlling fluid flow therethrough, g. second valve means having an open and a closed position and being located in said second conduit means, said second valve means including a valve member providing a high flow rate path and a valve member providing a restricted flow rate path, h. a measuring device for monitoring advancement of said material by the rollers and for emitting a slow down signal and a stop signal under predetermined conditions, and i. means controlled by said slow down signal for moving said high flow rate path valve to closed position and means controlled by said stop signal for moving said restricted flow rate path valve and said first valve means to closed position.

8. A device according to claim 5 wherein said second conduit means includes a pair of parallel conduits providing the high flow rate path and the restricted flow rate path, each of said parallel conduits containing a valve member having an open and a closed position.