Patent GB-817841-A (GB)
Title: An automatic feed for delivering work-pieces to a machine and more particularly to a machine tool
IPC: B25J9/00
Filed: 1956-11-08
Abstract: 817,841. Machine-tool details; transferring blanks. SOC. ORNANAISE DE CONSTRUCTIONS MECANIQUES SOC. Nov. 8, 1956 [Nov. 8, 1955], No. 34166/56. Classes 83 (3) and 83 (4). Also in Group XXX] In the automatic feeding of blanks to a machine-tool, such as a press, tongs 4, Fig. 5, transfer a workpiece 6 from a supply table 7 to a working position 8 on the machine, by vertical and horizontal movements effected by hydraulic pressure, the opening and closing of the tongs being pneumatically controlled. As applied to a stamping &c. press, the feedmechanism has a frame 1 carrying a slide 2 and an air-distributing member 3 which, through valves, opens and closes the tongs and ejects the completed workpieces. The slide 2 is moved hydraulically by a piston 10 in a cylinder 9, and cams 11-13 on the slide actuate slide valves to control the distribution system. A slide valve 16, Fig. 6, actuated by cam 13 against a spring 15, controls air supply to a work-ejector 17, and a slide valve 21, Fig. 8, actuated bv a screw 77 on slide 2, controls the air supply to the tongs. The tongs comprise a cylindrical body 51, Fig. 13, carrying levers 54 pivoted at 55. Work-engaging arms 57, connected to the levers 54 by screws 56, are held apart by a spring 58 and are closed by a piston 60 in the cylinder 51, having a conical portion 61 engaging the levers 54. Vertical movement of the tongs is effected by a piston 23, in a cylinder 22, connected by a fork 25 to a lever 28, Fig. 3, pivoted at 29 and connected to a tongs-holder 31 by a ball-joint 30. The tongs are carried by a shaft 40 adjustably mounted by a slide 47 on a guide 41, pivoted at 5 on the tongs-holder 31. Pins 38, 44, on slide 2, engage recesses 43, 44 in a plate 42 attached to the guide 41 to prevent angular displacement of the tongs during vertical movements, these being limited by a rod 66, Fig. 4, connected to the press-head A at 67, and to slide 2 through a lever and a rack-and-pinion. In operation, as the press-head A rises after a working-stroke, rod 66 moves slide 2 in direction F3, Fig. 5, to cause a cam 11 thereon to release a valve 36, Fig. 11, against pressure of a spring 35, and admit hydraulic fluid to cylinder 22. Piston 23 thus descends, and through lever 28, raises the tongs-holder 31, the pin 38 being in recess 43 of plate 42. The movement of slide 2 releases pin 44 from slot 39, and plate 42 rotates about pivot 5 to position guide 41, carrying the tongs, above the table 7. The pin 38 is released from the recess 43 and the plate 42 ceases to rotate, and the continuing movement of the slide 2 locks the tongs by the pin 44 engaging the slot 39. The tongs are lowered by the cam 12 actuating the slide-valve 36, and the piston 23 ascends, and through lever 28, lowers the tongs-holder 31. The tongs are closed on the workpiece by the slide 2, displacing the slide valve 21, through screw 77, Fig. 4, and supplying compressed-air to the piston 60, Fig. 13. A screw 78 then actuates a slide-valve 74, Fig. 4, to admit fluid into cylinder 9 to reverse the slide 2, causing the tongs-holder 31 to ascend. A reverse transferring movement positions and lowers the workpiece on to the machine. Completed workpieces are ejected by compressed-air supplied to member 17 by the slide-valve 16, which also operates a charger 64, Fig. 5, to deliver workpieces from a magazine to the tongs. Hydraulic control.-Pressure is supplied by a pump 79 driven by a motor 80, Fig. 14, and regulated by a valve 81 which feeds the cylinders 32, 86 connected to a valve 82 controlling a slide-valve 83. The cylinder 9 is fed through valve 82 to displace the slide 2. In operation, oil pumped into the cylinder 32 displaces, through slide-valve 34, the piston 23 to raise and lower the tongs-holder 31, through lever 28.