Patent GB-839133-A (GB)
Title: "transfer mechanism"
IPC: B21D43/10
Filed: 1957-06-11
Abstract: 839,133. Feeding mechanism for stamping presses. U.S. INDUSTRIES Inc. June 11, 1957 [Aug. 14, 1956], No. 18380/57. Class 83 (4). [Also in Group XXVIII] Mechanism for transferring objects between work stations for the performance of successive operations thereon, comprises means operable to pick up objects from a station, second means operable in response to operation of said first mentioned means to rotate said first mentioned means to another station, and means operable in response to movement of said first mentioned means to the other station to release the objects from said first mentioned means. In an embodiment each transfer device 7, interposed between a line of stamping presses 1, 2 and 3, is mounted on a support 6 and consists of two arms 8, 9 arranged at right angles so that the pick-up device 10, 11 on arm 8 picks up a workpiece from e.g. the press 1 and transfers it to an idler station intermediate the presses 1 and 2, where it is inspected or inverted, and the other arm 9 simultaneously transfers a workpiece in its pick-up device 12, 13 from the idler station to the press 2. The pick-up device may be of the vacuum or magnetic type. Each arm consists of supporting rods 14 secured to a plate 15 pivotally mounted in a block 16, attached to the lift cylinder 18 of the elevating means (Fig. 7). A tubular housing 19 is adjustably secured to the rods 14 by clamping means 21. A fluid-operated piston in the form of a sleeve 27 slides within the housing 19 and a rod 29 slides within the sleeve 27 and is arranged to move both with the sleeve and with respect thereto. The outer end of the sleeve 27 carries a disc assembly 30 slidable thereon and the outer end of the rod 29 carries a plate 34 which is spring-loaded against an abutment within the sleeve 27. This arrangement enables an initial and final movement of the sleeve 27 without movement of the rod 29 in order to open or close the jaws 10 and 11 of the pick-up device. The opening and closing of the jaws is effected by means of ears 39 and 40 on the disc 30 (Fig. 6) which pivotally carry the jaws so that their bifurcated tailpieces 41 pivotally engage an arm 43 extending outwardly from each side of the plate 34 on the rod 29. On initial inward movement of the sleeve 27 the plate 34 and the arms 43 remain stationary but the disc assembly 30 together with the jaws 10 and 11 move inwardly and the pins 44 traverse slots 45 on the arms 43 thereby causing the jaws to open. The entire assembly continues'to move inwardly until fluid pressure is admitted to the annular space 47 to reverse the sleeve movement. When the rod reaches its outermost position the sleeve continues its movement until the pins 44 traverse the slots 45 in the opposite direction and close the jaws. Each of the arms 8 and 9 has mounted thereon mechanically actuated three-way valves 52 and 53 for operating the lift cylinder of the elevating means and the indexing means respectively. Elevating and indexing means.-These are contained in a casting 55 and comprise a vertical lift cylinder 56 and a horizontal indexing cylinder 57. A rod 18 carrying the mounting block 16 for the arms extends through the lift cylinder and rotatably engages in a bore in the lift piston 58. A rod 70 attached to the piston 58 extends through the bottom cap member of the lift cylinder and carries a plate 72 normally spring- loaded against the plunger of a three-way valve 76. When the lift, piston is raised by fluid pressure the plate will actuate a second threeway valve 77 to direct pressure fluid to the indexing cylinder for rotating the rod 18 and the arms 8 and 9. The rod 18 is provided, around part of its periphery, with teeth 79 and opposite to the teeth a block 80. The teeth 79 mesh with teeth 89 on the indexing piston 90 and the amount of reciprocation of the piston 90 is controlled by adjustable end caps 93, 94 in the cylinder 57. The amount of rotation of the arms is adjusted by set screws 83 and 84 (Fig. 9). After the indexing the pressure fluid in all lines is exhausted and the spring 75 returns the elevating means to its lowermost position whereupon the plate 72 actuates valve 76 to direct pressure fluid to retract the sleeve 27 and release the workpiece at the next station. The arms will eventually operate the three-way valves 53 to reverse the movement of piston 90 to rotate the elevating means and the arms back to their initial position. Vacuum pick-up.-The vacuum-producing device 98 (Fig. 10) is mounted on the block 16 and includes a cylindrical chamber 101 having a neck 100 through which reciprocates a rod 102 carrying a spring-loaded piston 103 intermediate its ends. A bevelled sleeve 105 on the lower end of the rod actuates an arm 109 of a valve 110 (Fig. 3) which directs fluid pressure to the lift cylinder. In operation, pressure fluid unseats a ball valve 116 and moves the rod and piston downwardly to create a vacuum through the openings 119 and 120 sufficient to pick up a workpiece. Each vacuum head comprises a spring-loaded piston 129 mounted on a cylinder 128 closed by a bored cap 130 having an extension 131 which slidably engages in the piston 129. A flanged tubular member 134 is screw-threaded into the bottom of the piston and an annular recess in the member houses a rubber ring 136 for engaging a workpiece. The opening 141 is connected by a conduit to the opening 117a on the vacuum producing device and the openings 119 and 120 on said device to the bore 133 of the cap 130. When the fluid pressure is exhausted the valve 116 closes and piston 103 is elevated by its spring 111 and the piston 129 returns to its initial position in readiness for the next cycle of operation. To ensure simultaneous operation of a series of transfer mechanisms an arm 144 is mounted on each indexing cylinder 90 and each arm joined by a link 145.