US3762198A - Apparatus and methods for handling strip material - Google Patents

Apparatus and methods for handling strip material Download PDF

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US3762198A
US3762198A US00237827A US3762198DA US3762198A US 3762198 A US3762198 A US 3762198A US 00237827 A US00237827 A US 00237827A US 3762198D A US3762198D A US 3762198DA US 3762198 A US3762198 A US 3762198A
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fluid
motor
strip
hydraulic
supplied
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E Bair
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General Electric Co
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General Electric Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C49/00—Devices for temporarily accumulating material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D43/00—Feeding, positioning or storing devices combined with, or arranged in, or specially adapted for use in connection with, apparatus for working or processing sheet metal, metal tubes or metal profiles; Associations therewith of cutting devices
    • B21D43/02—Advancing work in relation to the stroke of the die or tool
    • B21D43/021—Control or correction devices in association with moving strips
    • B21D43/022—Loop-control

Definitions

  • ABSTRACT Apparatus includes strip material supply means, a press, and a straightening roller stand (i.e., a straightener having rollers) disposed adjacent to a mechanical press or other material processing device to which strip material is introduced in discrete steps.
  • the strip material is fed from a reel through straightening rollers and then to the press die set, with a slack loop of material in a temporary material storage locale between the straightening rollers and the die set.
  • a positive displacement fluid motor is used to drive the straightener, the fluid motor being connected with fluid flow control means that in turn are controlled in synchronism with operation of the press or other material processing device.
  • a supercharging pump maintains the fluid system charged while the pump, in effect, meters fluid to the motor.
  • Hydraulic circuit means are provided to fine tune the hydraulic system and synchronize the fluid motor in a desired manner.
  • Detector means are provided and control the slack loop to maintain it within predetermined limits.
  • Means associated with the detector means operate to divert or otherwise control leak age fluid from the motor inlet when the slack loop ex ceeds a predetermined maximum length, and to supply additional fluid to the fluid motor inlet when the slack loop shortens to less than a predetermined minimum length.
  • the present invention relates to apparatus and methods for handling strip material and, more particularly, to methods and arrangements for driving a mechanism acting on a strip of material that is being fed to a mechanical press.
  • Exemplifications of the invention embody hydrostatic drive arrangements for rollers acting on a strip and to means and methods for controlling the same.
  • a strip of steel is usually fed from a supply roll or reel through a set of dereeling or straightening rollers, e.g., to remove curvature from the strip as it approaches the press die set.
  • Presses generally require an intermittent feed of material, with the strip dwelling in the press while a stamping or other operation is performed.
  • the strip of material must, in such a case, pass through rollers such as straightening rollers at a relatively constant and uniform speed even though the strip is moved intermittently past or through the die set in the press.
  • the straightening rollers usually include one or two driven feed rolls.
  • the driving of the feed rolls may be accomplished by a mechanical connection extending from the press crankshaft to the feed rolls or may be accomplished by driving the feed rolls with a rotary motor, such as an electric motor.
  • the difficulty always presents itself, however, of synchronizing a desired continuous feed of the strip through the straightening rollers with an intermittent movement of the strip through the die set in the press.
  • a slack loop usually is left in the material between the straightening roller set and the press, and variations in this loop may be employed for varying the speed of rotation of the feed rolls.
  • strip steel in the manufacture of steel laminations for electric motors, it is common to process strip steel so that reels of lamination steel are provided.
  • the strip steel on these reels will be partially processed, and be in the form of lamination blanks joined together by a thin web of steel.
  • Each blank in the strip will have one or more holes therein that, desirably, will be precisely located in a press die set when the press is operated to separate the lamination blanks from the strip.
  • the center of each lamination blank will have a single hole in the center thereof which may be subsequently used to accommodate a rotor shaft or the center of which will be the center of a rotor accommodating stator bore.
  • the holes will be located precise preselected distances from one another in the strip and the press will pass this same preselected amount of steel through the press die set during each press stamping cycle.
  • roller straighteners have fed material to a storage loop until a mechanical, swingably mounted, arm bearing on the strip has moved to actuate a limit switch and stop the driven straightener rollers. Then, as a press took material from the loop, the mechanical arm would swing up as the loop diminsihed in size and the rollers would then start and re-establish an oversized loop. Thus, the straightener rollers would cyclically start and stop, and the strip material would be stressed as it was pulled in jerks from the supply reel.
  • an object of the present invention is to provide improved methods and apparatus for handling strip material.
  • Another object of the present invention is to provide methods and apparatus for synchronizing the continuous movement of strip material into a storage loop locale with an intermittent movement of strip material away from the storage locale.
  • Still another object of the present invention is to provide methods and apparatus for driving strip material through a set of straightening rollers for supply to a press, and for finely controlling the speed of movement of the strip material.
  • a more specific object of the present invention is to provide methods and arrangements for substantially continuously driving one or more rolls of a straightening apparatus by hydraulic means that are responsive to the operation of a press so that high speed press operation may be established and maintained without elongation or otherwise damaging strip material that extends between the straightening apparatus and press.
  • the present invention is exemplified and practiced in one form thereof, with apparatus comprising strip supply means, a press, and a straightener having rollers disposed adjacent to a mechanical press to which strip material is introduced.
  • the strip material is fed from a reel through straightening rollers and then to the press die set, with a slack loop of material in a temporary material storage locale between the straightening rollers and the die set.
  • a fluid motor is used to drive the straightener, the fluid motor being connected with fluid flow control means that in turn are controlled in synchronism with press operation.
  • the fluid flow control means may be a positive displacement hydraulic pump and the fluid motor a positive displacement unit matched to the pump.
  • a supercharging pump then is connected to the inlet side of the pump and maintains the fluid system charged while the pump, in effect, meters fluid to the motor.
  • Hydraulic circuit means are provided to fine tune" the hydraulic system and synchronize the fluid motor in a desired manner.
  • Detector means are provided and control the slack loop to maintain it within predetermined limits.
  • Means associated with the detector means operate to divert fluid from the motor inlet when the slack loop exceeds a predetermined maximum length, and to supply additional fluid to the fluid motor inlet when the slack loop shortens to less than a predetermined minimum length.
  • FIG. 1 is a perspective view, schematically illustrating apparatus comprising a mechanical press and a straightening roller stand and embodying my invention in one form, and which may be used to practice a method exemplifying my invention;
  • FIG. 2 schematically illustrates a hydraulic circuit useful for a desired mode of operation of the apparatus of FIG. 1;
  • FIG. 3 is a perspective view showing the physical arrangement of some of the components of the hydraulic circuit of FIG. 2;
  • FIG. 4 schematically illustrates an electric control circuit that controls the operation of the hydraulic circuit of FIG. 2.
  • FIG. 1 a mechanical press is schematically indicated at and has mounted therein a die set 12 for operating on segments of a strip of material, indicated at 14.
  • Strip 14 consists of a series of interconnected disc-like elements, each with a central hole. Within the die set, the elements are intermittently separated from each other and punched to form laminations for an electric motor having winding accommodating slots therein.
  • the strip 14 is fed from a reel 16 of the material and passes from the reel through material handling means illustrated as a straightening roller stand, generally indicated at 18.
  • the straightener comprises a conventional arrangement of a pair of superimposed rows of rollers which are staggered in the direction of movement of the strip 14.
  • the strip 14 is thus fed between the rollers, and the rollers serve to straighten out the strip, removing any bend therein.
  • One or both of the feed rolls of the straightening stand 18 are driven by means of a sprocket 22 which is connected with a motor driven sprocket 24 by a chain 26.
  • a belt preferably in the form of a timing belt so as to prevent slipping between the belt and cogged pulleys of course could also be used.
  • Pulley 24 is driven by a fluid motor 34 (best represented in FIGS. 2 and 3).
  • the fluid motor 34 is connected by conduits 28 and 30 in circuit with suitable fluid supply means, e.g., a pump, metering valve means, or a pump used to meter a fluid.
  • suitable fluid supply means e.g., a pump, metering valve means, or a pump used to meter a fluid.
  • the fluid supply means includes a fluid pump 32 mounted on press 10 and driven through suitable means in synchronism with the crankshaft of the press, e.g., by a timing belt or chain drive, so as to provide a positive interconnection between the fluid pump 32 and the press crankshaft.
  • FIG. 2 schematically illustrates the hydraulic circuit interconnecting fluid pump 32 and the fluid motor 34 which drives the feed rolls of the straightening roller stand.
  • the fluid motor 34 has the inlet side thereof connected with the outlet side of pump 32 by conduit 28.
  • the inlet side of pump 32 is connected by conduit 30 with the discharge side of a supercharging pump 36 which is driven by a motor 38.
  • the suction side of supercharging pump 36 is connected by conduit 40 to a filter 42 located in a reservoir 44.
  • valve 48 that acts as a relief valve and as a valve for decelerating and braking motor 34.
  • valve 48 discharges fluid through exhaust conduit 50 to a heat exchanger 52 to the aforementioned return conduit 40.
  • valve 48 vents the hydraulic fluid with about 5 pounds per square inch back pressure from the motor 34 to the heat exchanger 52 where the fluid is cooled, and from which it then returns to the conduit 40.
  • Valve 48 has a pilot or control line 54 leading to a valve 56 that is controlled by a solenoid 8-1.
  • the outlet side of valve 56 is connected by conduit 58 to the reservoir 44.
  • valve 48 When solenoid S-l is energized, the control line 54 is opened so that fluid may freely pass from valve 48 through the control line 54 back into the reservoir, and the valve 48 will still pass fluid above 5 psi to line 50. However, 500 pounds per square inch pressure on the inlet side of valve 48 is required for flow from line 46 through valve 48 when the control line 54 is closed by valve 56.
  • valve 48 acts as a high pressure relief valve, and vents fluid from line 46 only when the pressure in line 46 exceeds about 500 psi.
  • This condition normally occurs when the press is stopping and it is desired to stop motor 34. It will be understood that it is desirable to prevent freewheeling of motor 34 under this condition, so when solenoid S-l is deenergized, the inertia of motor 34 will cause a build-up of pressure in line 46 and this in turn will cause motor 34 to decelerate and stop as the pump 32 stops with the press. Thus, with the solenoid S-l deenergized, fluid passes through the valve 56 from the conduit 74 to the conduit 58.
  • conduit 54 is closed and the valve 48 is held in its 500 pounds per square inch high pressure relief or venting state.
  • solenoid S-l is again energized, fluid passes from conduit 54 to conduit 58 and valve 48 assumes its 5 pounds per square inch venting state.
  • drain line 60 leads from each of pump 32 and motor 34 back to reservoir 44 and conveys such slippage or leakage fluid back to the reservoir by any suitable drain line.
  • Charging pump 36 may be by-passed by fluid flowing thru a safety check valve 62 that will permit fluid flow from the reservoir 44 to lines 64 and 30 in the event that pump 36 should stop while pump 32 is still being driven.
  • This valve and a safety check valve 63 that is in a conduit parallel with the heat exchanger 52 function to prevent any accidental damage to their associated hydraulic circuit elements.
  • Valve 63 is normally set at about 30 or 40 psi to prevent damage to the heat exchanger in the event that it should become blocked.
  • check valve 62 and charging pump 36 are connected to a conduit 64 which is connected through a variable choke or flow control valve 66, a check valve 68, and a conduit 88 so that fluid is supplied to an inlet port of a valve 70 which is controlled by solenoids S-2 and S3 for a purpose to be described hereinafter.
  • Check valve 68 is provided as a safety feature for the hydraulic circuit to insure that back flow cannot occur in line 88.
  • Conduit 64 is also connected to the inlet side of a pressure relief valve 72 which is set to open at a pressure of about 200 pounds per square inch when its control or pilot conduit 74 is not vented back to the reservoir 44 through valve 56.
  • the conduit 74 is not vented to the reservoir when solenoid Sl of valve 56 is energized.
  • the pressure level for relief valve 72 drops to around 90 pounds per square inch when solenoid S-l is de-energized so that flow from line 74 to line 58 through valve 56 occurs.
  • the discharge side of valve 72 is connected to conduit 50.
  • Conduit 64 is also connected to a pressure indicating gauge 76 and a pressure safety switch 78 set to close for pressures above a predetermined minimum pressure, e.g., above the low pressure setting of valve 72. The switch 78 then will open if pressure in line 64 drops below a set minimum level.
  • valve 70 has a discharge port connected by conduit 80 with conduit 28 and also with the inlet side of a pressure relief valve 82.
  • the valve 82 is set to open if excessive pressure builds up in line 28. In the exemplification, if pressure in line 28 exceeds about 700 to 800 pounds per square inch pressure, valve 82 will pass fluid from line 28 and 80 to exhaust conduit 50. High pressure in line 28 may occur when the press starts and stops, for example.
  • Valve 70 also has an exhaust or discharge port through which fluid can discharge through conduit 84 and an adjustable choke or flow control valve 86 to reservoir 44.
  • Valve 70 is a three position valve and is normally in its centered position. When valve 70 is in its centered position and neither of solenoids S2, S3 is energized, all ports of valve 70 are closed so that conduits 80, 84, and 88 are shut off from each other. Upon energization of solenoid S3, valve 70 will shift to connect conduit 80 with conduit 84, thereby permitting fluid to flow from conduit 28 through conduit 80 and valve 70 to conduit 84 and then through choke or flow control valve 86 to the reservoir 44. The flow control valve 86 is adjusted to obtain any desired controlled fluid bleedoff rate from the line 28. This then controls the rate at which motor 34 will slow down while solenoid S3 is energized.
  • valve 70 shifts and connects conduit 88 with conduit 80 to supply additional fluid to conduits 80, 28, and motor 34 from pump 36 through conduit 64, flow control valve 66, check valve 68, and conduit 88.
  • the flow control valve 66 is adjusted to provide the desired rate and amount of speed increase of motor 34 while solenoid S2 is energized.
  • Valve 56 is a two position valve and when no material is to be fed from the rollers 92 the valve 56 (with solenoid Sl de-energized) is positioned to interconnect control or pilot conduit 74 and exhaust conduit 58, while closing off control conduit 54. Under these circumstances, valve 48 acts as a pressure relief valve and will not open until the pressure in line 46 reaches about 500 pounds per square inch. Thus, rotation of motor 34 is effectively prevented. Under these same circumstances relief valve 72 opens with a pressure in line 64 of about 90 pounds per square inch or more. Then fluid from charging pump 36 flows through line 64, valve 72, line 50, and heat exchanger or cooler 52 to the reservoir 44.
  • valve 48 switches to its open condition with a back pressure on line 46 of about 5 pounds per square inch. This permits motor 34 to rotate. Since valve 72 is effectively prevented from opening, the charging pump 36 will hold pressure of about 250 pounds per square inch on lines 64 and 30. If the pressure in lines 64 and 30 exceeds the desired 250 psi level, valve 72 will pass excess fluid from line 64 to line 50.
  • pump 32 is drivingly connected as by timing belt 88 with a rotary part of the press drive train, for example, the press crankshaft 90.
  • a rotary part of the press drive train for example, the press crankshaft 90.
  • operation of pump 32 is exactly synchronized with the press and the shaft of pump 32 will turn a given fixed amount for each and every stroke of the press.
  • faster strokes by the press will cause faster movement of the pump 32.
  • the volume and rate of flow of fluid passing through pump 32 is precisely controlled by actual press operation.
  • the feed rolls 92 of the straightening roller stand are positively interconnected with motor 34 by a timing belt and toothed pulleys or other means as described above.
  • Pump 32 and motor 34 are positive displacement units and may be, for example, in the form of piston units. Accordingly, there is substantially no slip in the hydraulic coupling of the pump 32 to the motor 34.
  • Such pumps and motors can be relatively small and lightweight so that the response of the motor to rotation of the pump is extremely rapid and full torque is developed on the motor relatively quickly.
  • a desired predetermined speed ratio may be established between the speed of rotation of primary press driving element 90 and the driven feed rolls 92 of the straightening roller stand.
  • the rollers 92 may be driven continuously to supply strip material at a substantially constant and uniform rate to an intermediate loop or temporary material storage locale while the press intermittently takes material from the loop or temporary storage locale. It will be understood that this ratio may be quickly determined from the feed per stroke and strokes per minute for the press. For example, for steady state operation with a feed of 6 inches of material per press stroke, and 10 press strokes per minute, the rollers 92 desirably will constantly supply 60 inches of material per minute to the temporary storage locale.
  • the motor 34 would then desirably drive the roller 92 at exactly four revolutions per minute. Accordingly, the drive ratio between press member 90 and pump 32, and the drive motor 34 and roller 92 would be selected to provide this desiredl performance.
  • FIG. 2 shows a slack loop that establishes a temporary storage locale.
  • the loop 20 is guided between a detector D1, which detects an excess amount of material in the loop and a detector D2 which detects a short loop condition.
  • detectors may be any suitable type, e.g., mechanical, optical, proximity, etc. For purposes of exemplification, commercially available mechanical and proximity detectors were used.
  • Proximity detector D2 is mounted on an arm 94 pivoted at 96. If the arm 96 is lifted by excessive shortening of the slack loop, still another detector in the form of a limit switch LS1 is switched to an open circuit condition for a purpose described later herein.
  • conduit 28 is connected to an adjustable bleed or flow control valve 98 that discharges to the reservoir or sump 44.
  • this bleed valve 98 can be fine tuned" to the point that the control provided by one or the other of the detectors D1 and D2 will rarely be required.
  • Use of the bleed valve 98 is particularly desirable when the linkage between the motor 34 and the feed rolls 92 is, for example, a chain and sprocket arrangement whereby the speed ratio of the two sprockets can be changed only by discrete steps.
  • the feed rollers 92 should in theory execute 1.98 revolutions for each revolution of pump 32, sprockets would probably not be available to conveniently provide the desired drive ratios.
  • pump 32 and motor 34 being selected as substantially identical and matched units, a drive between motor 34 and roller 92 would be provided to drive roller 92 at a 2 to 1 ratio relative to motor 34.
  • the bleed valve 98 would then be carefully adjusted to bleed fluid from line 28 so as to provide the desired drive ratio of roller 92 relative to pump 32.
  • the valve 98 is used to fine tune" the system so that relatively infrequent, if any, correction by detectors D1 and D2 is needed.
  • a safety device 300 is provided across lines or conduits and 28. This device is a pressure differential check valve which prevents direct fluid flow from line 30 to line 28. However, if line 30 should rupture or the sump 44 should run dry and if pump 34 should be operated under this condition; the valve 300 will circulate oil from line 28 (as it is discharged by pump 32) back to line 30 and thence to the inlet of pump 32.
  • FIG. 3 shows the manner in which the valves and other components referred to in FIG. 2, including charging pump 36, electric motor 38, and fluid motor 34, are organized to fit within the base portion of a commercially available roller straightener of the type available from the F. .I. Littell Machine Company of Chicago, Ill.
  • the motor 34, and the matching positive displacement pump 32 of FIG. 1, as well as many of the other components illustrated in FIG. 3 are commercially available items.
  • the illustrated pump and motor are radial piston matched displacement devices marketed as a Kawasaki Staffa type B-l0 motors by Kawasaki Heavy Industries, Limited, Oil Hydraulic Machinery Division, Kobe, Japan.
  • the heat exchanger 52 was a Young type OCH-24 forced air radiator, and the pump 36a Delaval type 3-BI18.
  • the Double A designations of the control valves are: solenoid actuated valve 70, 2F-005C10-AILI(; solenoid actuated valve 56, QJ-0O5Pl0-AILK; valve 72, BT-O6K1OA2; valve 82, BT-06KIOA2; and valve 48, BT0610A2.
  • Check valves 62 and 63 were Vickers valves, types C2815 and C2820 respectively.
  • a manifold 97 was constructed and used for a base for the two solenoid actuated control valves 56 and 70. The manifold also was machined to provide the check valve 68 and the three adjustable flow control valves 66, 86, and 98.
  • FIG. 4 schematically illustrated an electric control circuit that may be used to operate the valves and other apparatus shown in FIG. 2.
  • electric motor 38 will be seen to be controlled by contactors 108 of a commercially available control in a conventional manner.
  • a transformer 102 energizes poser lines L1 and L2 of the control circuit when master switch 100, across a 60 Hz 220 volt line is closed. Between the secondary of transformer 102 and line L1 is a circuit breaker 104 and a normally closed STOP" pushbutton 106.
  • a relay coil 108R that operates contactors 108 for control of motor 38 is connected between lines L1 and L2 in series with a normally open START pushbutton 110 and thermally actuated motor overload contacts 109.
  • a fan motor 112 for circulating air through the heat exchanger 52 and an indicating light 114.
  • This indicating light 114 is physically located on a small control panel of the straightener as illustrated in FIG. 1.
  • the control panel also contains the STOP switch 106, the START switch 110, a normally closed PRESS STOP switch 124, a JOG switch 128, a two-position selector switch 122 for automatic or manual press stroke operation, and a RUN switch 118.
  • pressure switch 78 Connected in parallel with switch 110 is pressure switch 78 which is closed so long as pump 36 maintains a desired pressure level in line or conduit 64 of FIG. 2.
  • the normally open contacts 108a of motor starter relay 108R are in series with switch 78. Switch 78 and contacts or blades 108a, when closed, connect line Llb and line L1.
  • RUN pushbutton switch 118 Connected between lines Llb and L2 is the coil of relay coil 116 in series with a normally open RUN" push-button switch 118.
  • RUN pushbutton switch 118 is by-passed by a branch containing contacts 116a under the control of relay coil 116, a normally open switch section 120 of selector switch 122 and a normally closed switch section of STOP pushbutton 124.
  • Switch 122 when adjusted for hand or manual operation has its section 120 open and when adjusted for automatic operation has its section 120 closed.
  • relay 116 functions as a latching relay and maintains itself in an energized state by way of its own normally open contacts 116a (which close when the coil of relay 116 is energized), provided the switch 122 is in its automatic position (with switch 120 closed) and further provided that the normally closed PRESS STOP switch 124 isclosed. The relay 116 then is latched by momentarily closing the RUN switch 118.
  • Switch section 126 is closed when selector switch 122 is set for hand operation and is open when the selector switch 122 is set for automatic operation.
  • the serially arranged pushbutton JOG switch 128 and switch section 126 are by-passed by a parallel circuit or branch containing normally open blades 116B under the control of relay coil 116 and contacts 130 that are controlled by the control circuit for the press which is not shown.
  • contacts 130 When the press is clutched in and running, contacts 130 will be closed; when the press is declutched, contacts 130 will be open.
  • Solenoid S-1 will be energized when relay 116 is energized, and the contacts 130 are closed because of operation of the press; or when switch section 126 is closed by setting the selector switch for hand or single cycle operation, and switch 128 is closed by depressing the .106 button.
  • Solenoid S-l is, of course, energized furing the normal running operation of the straightener motor 34, and deenergized when the straightener is idle. Solenoid S-l is also energized when LOOP FEED" switch 203 is closed provided contacts 1168 are closed.
  • the circuit for similar proximity detectors D1 and D2 is schematically illustrated as being connected between lines Llb and L2.
  • detector D1 When detector D1 is actuated indicating that the slack loop is too long, a coil of relay 132 is energized, and a holding circuit therefore is provided through contacts 1320 of relay 132 and normally closed contacts T2a of a timer T2.
  • detector D2 is actuated whereby relay 134 is energized and a holding circuit therefore is established through contacts 134a thereof and normally closed timer contacts Tla of a timer T1.
  • the timer T2 and a parallel resistor 136 are connected across lines Llb and L2 by way of the normally closed contacts or blades 1341; of relay 134, the normally open contacts 116d of relay 116, and the contacts 132b of relay 132.
  • Forming yet another branch in parallel with the relay device or timer T2 is the coil of solenoid S-3 of control valve 70.
  • the time device Tl has a similar parallel resistor 138, and that combination is similarly in parallel with the coil or solenoid S-2 of the control valve 70, and this parallel combination of T1, 138, S-2 may be in closed circuit relation across the lines Llb and L2 by either of two alternate branches.
  • the first branch comprises the normally open contact 128a of the JOG pushbutton while the other of the alternate branches comprises the series combination of the contacts 134a and 1160 of relays 134 and 116 respectively.
  • T1 and T2 in the illustrated embodiment are identical adjustable time delay structures having normally closed contacts which open a desired predetermined time interval (e.g., 10 seconds) after their initial energization, and may be of the Eagle CGl0A6 type.
  • delay device T2 After the prescribed time delay (e.g., 10 seconds) delay device T2 will open its contact T2a thus deenergizing relay 132 and causing the contacts 132a and 1321: of relay 132 to open. Opening of contacts 132b also de-energizes the solenoid S-3.
  • Delay device T1 is energized in a very similar manner when the detector D2 indicates that the slack loop 20 is too short, however, it should also be noted that contacts 128a may be manually momentarily closed to provide a manual correction and thus supply additional material from the straightener upon demand by the operator. This may be done, e.g., when strip material is first fed to the press.
  • a portion of the press control circuit is shown at the bottom of FIG. 4 and includes a series circuit loop containing switch section LSlA of limit switch LS1, contacts l08b and contacts 124b.
  • Section LSlA opens if the slack loop of strip material becomes dangerously short, contacts 108b open if relay 108R drops out, and contacts 124b open if PRESS STOP switch 124 is pressed. If any of these events occur, the electrical continuity between terminals 201 and 202 through the illustrated circuit loop is broken. Also, since terminals 201 and 202 are connected to the not shown press circuit, this will cause the press to declutch and stop using strip material.
  • contacts 130 When the press is declutched, contacts 130 will open. It should be noted that if limit switch LS1 is moved so that contacts LSlA open, contacts LSlB will close. Since contacts LSlB, upon closing, shunt contacts 130, opening of contacts 130 will not de-energize solenoid S-1 and cause the system pressure to drop, switch 78 to open, and motor 34 to brake and stop. Also assuming that the press is declutched so that the contacts 130 are open and further assuming that limit switch LS1 is not actuated so that contacts LSlB will remain open,
  • the motor 34 may be conditioned to run by manually closing the contacts 203 of the LOOP FEED switch.
  • solenoid 8-1 will be energized through manually closed contacts 203 so long as relay 116 remains energized and contacts 116B thereof are closed.
  • contacts 203 and 128a may be manually closed to feed material to the press while the press is declutched when switch 122 is set to automatic run and contacts 126 are open.
  • contactor 100 and switch 110 are closed to thereby energize motor 38 to drive pump 36 and also to energize the control system.
  • JOG pushbutton 128 can be used. With solenoid S-1 energized, control valve 56 causes fluid system pressure to rise, and pressure switch 78 closes. Actuation of JOG switch 128 energizes solenoid 8-1 of valve 56 and thus permits relief valve 48 to operate and also shuts off relief valve 72. Also, solenoid 8-2 is energized (when 106 contacts 128a are closed) to shift valve 70, thereby to cause motor 34 to rotate in a direction to feed strip material into the slack loop locale.
  • solenoid S-I may be energized, by manually holding contacts 203 closed to shunt contacts 130 as previously described.
  • valve 70 When the press is running on automatic cycle and contacts 1168, 116a, and 116d are closed, the detectors D1, D2 will control the shifting of valve 70 so that if the slack loop becomes too long, solenoid 8-3 will energize valve 70 so as to by-pass fluid away from motor 34, while if the slack loop grows too short solenoid 8-2 will be energized and shift valve 70 so as to supply additional fluid to motor 34.
  • the timers T1 and T2 control the length of time that the adjusting operations continue after the detectors operate and may be setfor a desired time delay period.
  • limit switch LS1 will open contacts LSlA because of movement of arm 94. This will interrupt the press control circuit as previously described.
  • pressing of STOP switch 124 to open its contacts 12412 or deenergization of relay 108R to open its contacts 108b will also interrupt the press control circuit.
  • depressing STOP" pushbutton 106 will interrupt the entire circuit, including the press control circuit.
  • apparatus or methods embodying the invention may be utilized to substantial advantage. For example, approxiestablish a material feed rate that will substantially equal the material utilization rate of the press.
  • slippage between a driven straightener roller and strip material; inability to economically establish theoretical gearing ratios; and amount of material on the supply reel; may be easily compensated for.
  • a control circuit for synchronizing first and second material processing devices which sequentially operate on a common length of material comprising: first and second fixed displacement hydraulic devices coupled respectively to the first and second material processing devices and each adapted to pass a volume of fluid which bears substantially the same relationship to the length of material operated on by the respective processing device; and means hydraulically interconnecting said first and second fixed displacement hydraulic devices and adapted to introduce a controlled leakage into the hydraulic system to correct for differences in the respective rates of consumption of material of the first and second material devices introduced by small differences between said relationships.
  • the method of operating the strip feeding means pertaining to a straightening roller stand to maintain a substantially fixed length of slack loop in the strip of material between the straightening roller stand and the machine being supplied thereby comprising: driving a positive displacement hydraulic pump by the machine; connecting a positive displacement motor to the strip feeding means; hydraulically interconnecting the pump and the motor; and introducing a controlled amount of leakage between the pump and the motor to thereby slow the motor slightly and make the average rate of supply of strip material from the feeding means more nearly the same as the average rate of consumption of the strip of material by the machine.
  • the method of claim 3 further comprising the steps of: sensing for excessive variations in the length of the slack loop; introducing additional leakage between the pump and the motor when the slack loop exceeds a predetermined maximum length; and introducing additional hydraulic fluid between the pump and the motor when the slack loop is less than a predetermined minimum length.
  • a machine having a member movable for operating on strip workpiece material fed into the machine at one side, said machine having a rotary element rotatable in unison with movement of said member, a straightening roller stand spaced from said machine on said one side thereof and having rotatable feed means and adapted to perform straightening operation on workpiece material while feeding the workpiece material toward said machine, and a hydrostatic transmission comprising a pumping element drivingly connected to said rotary element and a motor element drivingly connected to said feed means, and hydraulic conduit means connecting said elements in circuit.
  • said hydraulic conduit means comprise a main conduit connecting the outlet of said pumping element to the inlet of said motor element, and control means for varying the rate of supply of fluid to the inlet of said motor element.
  • control means includes an adjustable restricter connected between said main conduit and exhaust.
  • control means includes a first control valve connected to said main conduit, a variable flow control valve connected between said main conduit and exhaust; means for supplying high pressure fluid to said pumping element; said first control valve having ports connected to the high pressure fluid and exhaust, respectively; and means for shifting said first control valve to selectively supply or subtract fluid from said main conduit.
  • the invention of claim 9 further including actuating means for said first control valve, said actuating means including time delay means operable to maintain said first control valve in a selected actuated position for a predetermined time period following actuation thereof.
  • a first device for substantially continuously feeding strip material a second device located in spaced relation to the first device for intermittently performing a work operation on segments of strip material supplied by the first device; and means for controlling the operation of the first device in response to the operating condition of the second device; said means for controlling comprising: a first hydraulic mechanism interconnected with the second device; a rotary fluid motor drivingly connected to the first device; and hydraulic circuit means interconnecting the first hydraulic mechanism and the rotary fluid motor; said first hydraulic mechanism being operative to continuously supply hydraulic fluid to said hydraulic circuit means continuously during continuous operation of the second device and intermittently during intermittent operation of said second device; said rotary fluid motor operating in response to fluid supplied thereto through said hydraulic circuit means to thereby drive the first device so that a predetermined amount of strip material, sufficient in length to permit continued operation of the second device, will be supplied from said first device to said second device.
  • first hydraulic mechanism comprises a positive displacement unit interconnected by a slip free driving connection with the second device; said rotary fluid motor comprises a positive displacement unit; and said hydraulic circuit means includes means for continuously diverting a portion of the fluid moving into the hydraulic circuit means away from the rotary fluid motor so that under steady state continuous operating conditions, less fluid will move through the rotary fluid motor than is supplied to the hydraulic circuit means.
  • the structure of claim 13 wherein the first device supplies strip material to a temporary storage locale, the second device withdraws strip material from the temporary storage locale; sensing means are provided for detecting over-supplied and undersupplied conditions of the temporary storage locale; and wherein the detecting means are interconnected with said control means for selectively increasing and decreasing the amount of fluid supplied to the rotary fluid motor.
  • a method of operating strip feeding means to substantially maintain a predetermined amount of strip material in a slack loop between the strip feeding means and a machine being supplied thereby comprising: controlling fluid metering means by the machine being supplied; supplying high pressure fluid from the fluid metering means toward a positive displacement rotary motor and thereby driving the strip feeding means; and diverting high pressure fluid from the rotary motor to establish a preselected basic speed ratio between operation of the machine being supplied and the rotary motor.
  • the method of claim 15 further including detecting an undersupply of strip material in the slack loop and supplying high pressure fluid in addition to that supplied from the fluid metering means to the rotary motor.
  • the method of claim 15 further including positively driving the metering means in synchronism with operation of the machine being supplied; detecting an oversupply of strip material in the slack loop, and diverting more high pressure fluid from the rotary motor to thereby reduce the drive speed of the strip feeding means.

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4707106A (en) * 1986-03-03 1987-11-17 Polaroid Corporation Multiple format camera and accessory
US4736585A (en) * 1985-03-15 1988-04-12 Mannesmann Rexroth Gmbh Hydrostatic machine
US5392977A (en) * 1993-11-09 1995-02-28 Sankyo Seisakusho Co. Coil material supply apparatus for an intermittent feed device
FR2744938A1 (fr) * 1996-01-19 1997-08-22 Minster Machine Co Systeme de controle a boucle suiveuse amortie pour presse a estamper
US20010006182A1 (en) * 1998-09-08 2001-07-05 Rune Nilsson Method and device for feeding of long objects
US20090224021A1 (en) * 2008-03-05 2009-09-10 Garry Jensen Apparatus and method for processing coiled sheet-like material

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3333446A (en) * 1964-08-24 1967-08-01 Harper Laffie Sheet metal leveling and shearing apparatus and method
US3429164A (en) * 1966-04-08 1969-02-25 Armco Steel Corp Method of processing ferrous strip

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3333446A (en) * 1964-08-24 1967-08-01 Harper Laffie Sheet metal leveling and shearing apparatus and method
US3429164A (en) * 1966-04-08 1969-02-25 Armco Steel Corp Method of processing ferrous strip

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4736585A (en) * 1985-03-15 1988-04-12 Mannesmann Rexroth Gmbh Hydrostatic machine
US4707106A (en) * 1986-03-03 1987-11-17 Polaroid Corporation Multiple format camera and accessory
US5392977A (en) * 1993-11-09 1995-02-28 Sankyo Seisakusho Co. Coil material supply apparatus for an intermittent feed device
FR2744938A1 (fr) * 1996-01-19 1997-08-22 Minster Machine Co Systeme de controle a boucle suiveuse amortie pour presse a estamper
US5833105A (en) * 1996-01-19 1998-11-10 The Minster Machine Company Stamping press damped follower loop control system
US20010006182A1 (en) * 1998-09-08 2001-07-05 Rune Nilsson Method and device for feeding of long objects
US6422445B2 (en) * 1998-09-08 2002-07-23 Rune Nilsson Method and device for feeding of long objects
US20090224021A1 (en) * 2008-03-05 2009-09-10 Garry Jensen Apparatus and method for processing coiled sheet-like material

Also Published As

Publication number Publication date
FR2241977A5 (xx) 1975-03-21

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