Patent GB-908864-A (GB)
Title: Improvements in or relating to workpiece loading and unloading devices for machine tools
Inventor: DODGSON FRANK
IPC: B25J9/00
Filed: 1959-09-08
Abstract: 908,864. Conveyers. CHURCHILL-REDMAN Ltd. Sept. 8, 1960 [Sept. 9, 1959], No. 30568/59. Class 78 (1). [Also in Group XXII] An automatic loading and/or unloading device for machine tools, e.g. a copying lathe, comprises an arm pivoted at one end and having work gripping jaws at or near the other end, means for swinging the arm into or away from the lathe centres, and means for moving the arm laterally at one limit of its swing. An hydraulically-operated, electrically-controlled copying lathe comprises a headstock 10, Fig. 1, having a chuck 12, and a tailstock 14 with a centre 16, the tool post (not shown) being mounted vertically above the working position and the work being fed on a conveyer 20 to a position 22 where it is picked up by jaws carried by an arm 28, swung to the position 22a, machined, and then unloaded by a second swing arm 36, whose jaws grip the work and place it on a second conveyer 24 where it passes to a further machine or a discharge position. The arm 36, Fig. 2, is secured to a boss 120 keyed to a shaft 84 which is rotatably carried by a member 78 secured to a block 40 slidable on the headstock 10, the slidable movement being produced by a double-acting hydraulic piston 62. A spur-wheel 86 keyed to the shaft 84 engages a toothed rack 88, Figs. 2 and 5, which is actuated to swing the arm 36, by a doubleacting piston 92, enlargements 104, 114 being provided on the piston-rod to engage corresponding bores 102, 112, in the cylinder 94 at the ends of the stroke to reduce the flow of oil and therefore slow down the movements of arm 36, and a stop 124 engages a plate 122 on the arm 36 to limit its inward movement. The outer end of arm 36 carries a rotatable cylinder 134 having a chain sprocket 140 fixed thereto, which is connected to a sprocket 144 fixed to the member 78, by a chain 142, the sprocket 144 having twice the number of teeth of sprocket 140. This arrangement allows rotation of cylinder 134 when arm 36 swings about shaft 84. A piston-rod 148 having a double-acting hydraulic piston 150 is secured to a sliding block 168 having pins 184, Fig. 3, which engage elongated holes in jaws 174, 176, pivoted at 178 so that as the piston 150 and block 168 move upwardly in cylinder 134, the jaws move from the closed position to the open or chain-dotted position of Fig. 3. The end of loading arm 28 may have a similar arrangement of work gripping jaws except that jockey pulleys for the chain are required for the cranked end 32, or the cylinder may be non-rotatable and the chain sprocket may be omitted. In operation, the conveyer 20 arrives at the picking-up position and a switch is closed to operate a valve which supplies fluid to the piston of arm 28 and the jaws on the latter grip the work. A further switch is then operated and fluid is supplied to the piston operating the rack which swings arm 28 and the work to the loading position. The arm then actuates another switch controlling the supply of fluid to the tailstock 14 which moves to the left and after some lost motion picks up the head 26. The chuck jaws are closed and a switch actuates a valve to supply fluid to the piston of arm 28 to release the work and a further switch is actuated to move the rack of arm 28 to swing it back over conveyer 20. A switch is closed and the motor driving the lathe and feeding the cutting tool is started and when the operation is completed, a switch is closed which causes piston 92 to swing arm 36 to the loading position, the jaws grip the work, the chuck is released, the tailstock is moved away from the work and piston 62 is actuated to move the work out of the chuck. The movement of piston 92 is reversed, arm 36 is swung over conveyer 24, and the jaws are opened, thus releasing the work. The loading and unloading arms can be operated in reverse sequence.