US3040685A - Work-handling means for power-presses and like machines - Google Patents

Description

June 26, 1962 H. HJRIDLEY 3,040,685

WORK-HANDLING MEANS FOR POWER-PRESSES AND LIKE MACHINES Filed Nov. 17, 1958 2 Sheets-Sheet 1 June 26, 1962 H. H. RIDLEY 3,040,685

WORK-HANDLING MEANS FOR POWER-PRESSES AND LIKE MACHINES I Filed Nov. 17, 1958 r 2 Sheets-Sheet 2 United States Patent 3,043 685 WORK-HANDLING MEAIQ S FOR POWER-PRESE AND LEE MACHINES Harry Heywood Ridley, Aldridge, near Walsall, England,

This invention relates to work-handling means for power presses and like machines and more particularly to means for unloading workpieces from such machines.

According to my invention, work-handling means for power presses or like machines comprises a rigid substantially vertical arm carrying work-gripping means at its lower end mounted to swing about a point intermediate its ends on a pivot guided for movement along a fixed path, a lever mounted for angular movement about a fixed point and connected at one end to the upper end of the arm, and fluid pressure means for moving the lever angularly to cause the arm to move vertically and to swing about its pivot.

The gripping means is operated in synchronism with the movement of the arm, the arrangement for unloading or removing pressings from a power press being such that the gripping means is advanced to grip a pressing, the arm is raised through a small distance to lift the pressing, and the arm is then swung out to carry the pressing to a point where it is discharged by release of the gripping means, the arm then returning to its initial position.

The work-handling means may be set in motion automatically by the closing of a switch actuated either directly or through any convenient intermediate mechanism by a cam on the crankshaft of the press or by a striker or the like on the ram or slide, the switch being closed after the crankshaft has passed bottom dead centre.

A second switch is closed by a moving part of the work-handling means as the arm approaches the upper end of its movement to release the gripping means and allow the arm to return. A control actuated by a part of the gripping means may be provided to stop the press if the gripping means is not fully retracted when an appropriate point in the cycle of operations is reached.

Preferably the arm of the work-handling means is telescopic to allow its length to be adjusted to suit different presses, and it carries at its lower end gripping means movable in a substantially horizontal direction and incorporating fixed and movable jaws between which the work is held.

A practical form of work-handling means in accordance with my invention for unloading work-pieces from a power press is illustrated by way of example in the accompanying drawings in which:

FIGURE 1 is a side elevation of the complete workhandling means,

FIGURE 2 is a front elevation,

FIGURE 3 is a diagram showing the path of the arm,

FIGURE 4 is a diagram of the electrical control system.

In FIGURE 1, is a rigid bracket which is adapted to be bolted or otherwise secured to the frame of a press to carry the Work-handling means. The form of this bracket will depend on the design of the press.

Two spaced vertical plates 11 depending from the bracket form a rigid frame for the work-handling means and aligned slots 12 are formed in the plates. These slots are vertical throughout the major part of their length but a short part at the lower end is curved slightly as shown at 13.

The work-handling arm 14, at a point a short distance below its upper end, carries rollers 15 working in the 3,64%,685 Patented June 26, 1962 ice slots 12. The upper end of the arm is pivotally connected to the free end of a lever 16 which is pivoted at its other end about a stationary axis 17. About the middle of its length the lever has an integral depending lug '18 to which is pivotally connected by a pin 19 the free end of the piston-rod of a substantially vertical air cylinder 20 mounted to rock about a fixed pivot Z1 at its upper end;

To provide the necessary rigidity the upper part of the arm 14 is conveniently bifurcated, as shown in FIG- URE 2, with parallel limbs'fitting between the plates 11, and the rollers 15' are carried on the ends of a spindle mounted in a tube 22' extending between and welded to the limbs of the fork. The lever 16 is also bifurcated and is pivoted on a transverse pin mounted in-bosses 23 welded to the inner faces of the plates 11.

The arm 14 is telescopic, the lower part being adapted to telescope into the upper part so that the effective length of the arm can be varied to suit different presses.

A lug 25" pivotally mounted on the lower end of the arm'14 has secured in it a substantially horizontal bar 26. A sleeve 27 fixed on the bar carries a double-acting air cylinder 28 of which the piston-rod is'adapted to advance and close a gripper assembly 29 when the cylinder is energised. The form of the gripper jaws will depend on the work to be handled.

Air under pressure is delivered through flexible hoses to the air cylinders Ztland 28 under the control of a valve or valves by which the operation of the work-handling means is synchronised with that of the press.

In the normal position of the arm 14- as shown in the drawings, the rollers 15 lie at the lower ends of the slots 11 and the lever 16 is inclined downwardly at a small angle to the horizontal from its pivot to the connection to the arm.

In the operation of unloading or removing pressings from the press, the air cylinder 28 'is energised to advance the gripper assembly and close it on to: a finished pressing as soon as the tools have completed their operation and the moving tool has moved upwardly far enough to permit the entry of the gripper. Then after a predetermined time delay the air cylinder 20 is energised and swings the lever 16 upwardly about its pivot 17, and the angular and upward movement imparted to the arm in combination with the curvature of the lower end of the slots 11 produces a movement of the arm such that its lower end carrying the gripping means is first raised substantially vertically through a small distance and then is swung outwardly away from the press to carry the pressing outwardly away from the tools to a point where it is released.

The path of the gripping device is shown by the lines 31, 32 in FIGURE 3, the line 31 showing its path when the telescopic arm is at its shortest length and the horizontal movement of the gripper device is at its minimum.

The line 32 shows the path when these are at their maximum. In each case the pick-up point is indicated at 33 and it will be seen that there is a short substantially vertical movement of the arm to lift the pressing clear of the bottom tools before the arm begins to swing out.

The dotted lines in FIGURE 1 show the limiting upper positions of the lever 16 and the arm 14. These parts may be retained in that position by a bar inserted under the lever intoa hole 34 in the plates 11 in order to hold the arm and the gripper device out of the way for toolsetting or like operations.

The bar 26 carrying the gripper assembly will normally be substantially horizontal when the arm is in its rest position, but the angular relationship between the bar and the arm can be adjusted to suit particular circumstances. For this purpose a screw-threaded rod 35 pivotally connected to a laterally extending arm on the lug 25 is taken through a hole in a bracket 36 fixed on the arm and the angular position of the lug is adjusted by means of nuts 37 screwed on to the rod on opposite sides of the bracket. 7

The point in the outward movement of the arm at which the pressing is releasedis conveniently controlled by a switch 40 which is vertically adjustable on a rod 41 mounted in lugs on one of the plates 11, the switch being tripped by the lever 16 or by the arm 14.

A convenient layout for the automatic control of the work-handling deviceincorporating the switch 40 is shown in FIGURE 4.

When the crankshaft of the press haspassed bottom dead-centre and there is suflicient room for the gripper device to enter between the tools, a cam 45 on the crankshaft closes a switch 46 to energise one solenoid of a double solenoid-operated air valve 47. This admits air to the cylinder 28 which advances and closes the gripper device to grip the pressing. At the same time air is admitted through a controllable restrictor valve to a pilot operated master valve which, after a predetermined and adjustable time delay, admits air to the cylinder 20 which raises the arm with the gripping device and pressing and swings it outwardly. As the arm approaches the end of its movement the switch 48 is closed and energises the other solenoid of the valve 47 to reverse the valve. The energisation of the cylinder 28 is reversed so that the pressing is released and the gripper device is retracted, and the cylinder 20 is connected to exhaust so that the arm returns under gravity to its rest position. A manually operated switch 48 is provided to allow the work-handling device to be operated independently of'the press.

FIGURE 4 also shows a safety switching arrangement incorporated in the press control circuit.

A switch 49 adapted to be closed by a cam 50 on the crankshaft of the press is' connected in parallel with a pressure-operated switch 51 connected to and operated by the air pressure in the end of the cylinder 28 to which air is admitted to retract the gripping means, so that if the supply of air under pressure to that end of the cylinder should fail, the switch 51 opens and the switch 49 opens and stops the press as soon as the cam 50 clears the switch.

In an alternative arrangement a limit switch is mounted on the sleeve 27 and is adapted to be engaged by a striker on the moving part of the gripper assembly so that the press is stopped if the gripper has not been fully retracted when an appropriate point in the cycle is reached, whether the failure is due to failure of the air supply or to any other cause. e e

a It will be appreciated that work-handling means forms a complete unit which can readily be fitted to existing presses.

I claim:

1. Work-handling means for power presses comprising a frame, a substantially vertical arm, a horizontal pivot member carried by the arm and connected to the frame for substantially vertical movement relative thereto, work gripping means on the lower end of said farm, an actuating lever pivoted at one end on a fixed point on the frame laterally spaced from the path of movement of the pivot member and pivotally connected at the other end to the arm, and fluid pressure means operably connected to said lever for moving the lever angularly in a vertical plane to swing the arm about the axis of its pivot member and move it bodily in a vertical direction.

2. Work handling means for powerpresses comprising a frame, a substantially vertical arm, a pivot membercarried by the arm, work-gripping means on the lower end of the arm, means defining a fixed vertical path in the frame in which said pivot member is guided for movement along said path, an actuating lever mounted for angular movement in the frame about a fixed horizontal pivot laterally spaced 'from the path, a pivotal connection between the lever and the upper end of said arm, and fluid-pressure means operably connected to said lever for moving the lever angularly to cause the arm to move bodily in a vertical direction and to swing about the axis of its pivot member.

a 3 Work-handling means as'in claim 2 wherein said path defining means is a slot, said pivot member for the arm being slidably guided in said slot in the frame, the slot being vertical except for a short curved portion at its lower end in which the pivot lies in the normal rest position of the arm.

4. Work-handling means as in claim 2 wherein said pivot member comprises a pin fixed transversely in the arm a short distance from its upper end, rollers on said at an intermediate point in its length.

6. Work-handling means as in claim 2 wherein the dispositions of the arm, the actuating lever, and the path in which the pivot member of the arm is guided, are such that on energisation of the fluid pressure means the arm is first raised bodily through a small distance to lift a work-piece held in the gripping means clear of the tools of a press to which the work handling means is fitted and then-the arm is rocked angularly to carry the workpiece outwardly away from the tools to a point where i it is released.

7. Work-handling meansas in claim 2 wherein said work gripping means on the lower end of the arm comprises a gripping device slidably mounted on the arm 7 for movement thereon in a substantially horizontal direction and a double-acting fluid pressure motor adapted when energised in one direction to advance the gripping device into engagement with and close it on to a workpiece and when energised in the other direction to release the work-piece and retract the gripping device.

8. Work-handling means for a power press operating cyclically comprising a frame secured to the press, a substantially vertical arm, a horizontal pivot member carried by the arm and connected to the frame for substantially vertical movement relative thereto, work-gripping means on the lower end of said arm, an actuating lever pivoted at one end on a fixed point on the frame and pivotally connected to the arm, fluid pressure operating means operably connected to said lever for moving the lever angularly in a vertical plane to swing the arm about its pivot and move it bodily in a vertical direction, and a control means for energizing said fluid pressure means actuated by a moving part of the press during each cycle thereof to initiate an operative stroke of said arm in synchronism with the operation of the press.

9. Work-handling means as in claim 8 further comprising double acting fluid pressure means connected for actuating said work gripping means, a solenoid-operated valve means operable to energize said double-acting fluid pressure means in one direction to grip a work piece and subsequently, after a predetermined time interval, energize the fluid pressure means for moving the arm, said control means including a first switch actuated by a moving part of the press for controlling said valve to cause the gripping of a work-piece and the movement of the arm on an operative stroke of the press, and a second switch actuated by the arm for reversing the valve to cause the release of the work-piece and the retu-rn of the arm.

10. Work-handling means as defined in claim 8 further comprising press control means including means for-stopping the press upon failure of said double acting fluid pressure means, and means for rendering said last men- =tioned means operative at a predetermined point in the i 1 cycle of press operation.

11. Work-handling means for a power press or the like comprising an arm of substantial length having work gripping means at one end, a frame, mounting means for pivotally mounting the arm on the frame for swinging movement about a first pivotal axis extending transversely of the length of said arm, said mounting means permitting also movement of said first pivotal axis along a predetermined path, a lever pivoted to said arm on a second pivotal aXis' parallel to said first pivotal axis but spaced therefrom, means engaging said lever at point spaced from said second pivotal axis for guiding the path of movement of the lever, and fluid pressure means connected to the lever to move it along its path of movement and thereby to move said arm.

6 7 References Cited in the file of this patent UNITED STATES PATENTS 796,541 Tompkins Aug. 8, 1905 1,597,967 Grant et al. Aug. 31, 1926 1,859,956 Canfield May 24, 1932 2,275,561 'Sahlin Mar. 10, 1942 2,609,776 Sahlin Sept. 9, 1952 2,763,167 Sahlin Sept. 18, 1956 2,781,136 Sehn et a1 Feb. 12, 1957 2,811,266 Udal Oct. 29, 1957 2,868,582 Loisell Jan. 13, 1959 OTHER REFERENCES Sahlin Iron Hand Unloading Machines, Sahlin Engineering Co., PO. Box 289, Birmingham, Michigan, pp. Sand 8. v

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