Patent GB-927267-A (GB)
Title: Improvements in or relating to workpiece distributors
IPC: B21D43/10
Filed: 1962-03-26
Abstract: 927,267. Blanks transferring in metalworking presses. SOC. ORNANAISE DE CONSTRUCTIONS MECANIQUES. March 26, 1962 [Aug. 31, 1961], No. 11499/62. Class 83 (4). A distributer for feeding workpieces to a press or like machine of the type comprising a swinging arm provided with gripping means for seizing said workpieces from a point remote from the machine and transferring them to the tools of said press, said swinging arm being movable angularly in relation to two substantially vertical and horizontal axes, a connecting rod comprising a resilient telescopic section coacting with a movable plate for controlling the swinging movements of said arm during its movements about said vertical axis, the two end positions of said arm during its movements about said axis in a substantially horizontal plane being determined by a pair of adjustable stops, and cam members mounted on said movable plate and adapted to act upon one end of a lever causing with its opposite end said arm to swing about said horizontal axis when said arm is locked at the end of its stroke against one of said stops, said distributer being characterized in that said movable plate is driven for continuous rotation and comprises on its outer periphery two cams acting by turns during the rotation of said plate upon the end of said lever for successively controlling the vertical movement of said gripping means above the reserve of workpieces and above the tools of the press. In an embodiment the plate assembly 10 is driven through a V-belt transmission 11 from a gearbox and hydraulic clutch assembly 12. A telescopic connecting rod 14 has one end 13 pivoted to the plate and the other end 15 to one end of a swinging arm 16 carrying gripping means (not shown) e.g. clamps, an electromagnet, sucker-cups or the like. Stops 18 on a base member 19 limit the swinging movement of the arm about the axis 17. The base member 19 is spring-loaded and rockable about a horizontal axis X-X to impart vertical movements to the gripper arm 16. Such movement is imparted to the base member by an adjustable stop 23 mounted on the end of a fulcrumed lever 24 which is actuated by cams 28, 29 carried by the plate 10. A set-screw 30 limits the downward movement of the lever 24 thus limiting the amplitude of the vertical movements of the gripping means carried by the arm 16. The cam drum 10, Fig. 2, has dovetail grooves 37 to 40, the groove 40 accommodating the cams 28, 29 and the other grooves accommodate cams for controlling the auxiliary devices of the distributer. Fig. 4 illustrates diagrammatically the motor and reduction-gear unit 60 driving the clutch 70, 74 when fluid pressure is introduced into chamber 78 by operating a foot pedal 140. Cylinder 110 controlled by cam 106 actuates the clutch of the press to be fed with workpieces by the distributer. Cam 102 controls the jaws of the clamps 111 via a valve 115. Alternatively, an electromagnet 123, energized from a rectifier bridge 124 fed from a transformer 125 and controlled by a microswitch 126, is substituted for the clamp 111. When the cams 101 to 106 engage the valve rollers associated therewith they determine the following movements with the proper timing : ejecting and blowing the workpieces just pressed (cams 101 and 103); the clamp opening and closing movements or alternatively the energization of the gripping electromagnet (cam 102) ; if desired, controlling a workpiece loader or box (cam 104). Cam 105 operates a safety or emergency device, e.g. a treadle 132 controlling the clutch 70-74 of the motor reduction gearing 60 whereby the gripping means cannot be stopped outside a predetermined position when the distributer and the press fed thereby are stopped. Cam 106 controls the press clutch. In operation, the operator depresses the pedal 140 of the treadle 132 to position 2, whereupon the plate and cam drum assembly rotate to determine the movements of the clamp, the blowing and ejection of the workpieces and the workpiece handling loaders and the press clutch. The cam 105 opens at regular intervals the valve associated therewith thus causing downward movement of the piston 145 but this movement is inoperative since the pedal is in its lowermost position. When the operator releases the pedal the latter is maintained in position 1 during the time the valve associated with cam 105 is kept open by this cam whereby the gripping arm resumes its initial position. without allowing the press clutch to be engaged. The pedal returns to position O under the action of spring 142 when the valve associated with cam 105 closes and cuts-off the supply of pressure fluid to the piston 145 keeping the pedal in position 1 so that the distributer and press assembly stops completely. In another embodiment, Fig. 10, electrical control means are substituted for all the pneumatic control means of the first embodiment which can be so substituted. Assuming that switch 276 is closed, when the operator depresses the pedal 267 it closes both contacts 269 and 270, thus starting the motor 232. The press clutch is controlled at regular time intervals as the cam 252 moves past the micro-switch associated therewith. The gripping member (clamp 274 or electromagnet 275) is operated when the micro-switch corresponding to cam 251 is closed. When the operator releases the pedal both contacts 269 and 270 open simultaneously and the press clutch is disengaged immediately. The motor brake of the distributer however remains energized as long as the cam 253 does not engage its microswitch and thus enables the gripper arm to return to its initial position. Specifications 874,948 and 880,163 are referred to.