Patent GB-936651-A (GB)
Title: Improvements in or relating to work-feeding apparatus
Inventor: MURPHY BRIAN JULIAN MAURICE
IPC: A43D117/00
Filed: 1959-02-03
Abstract: 936,651. Feeding sheets. BRITISH UNITED SHOE MACHINERY CO. Ltd. Feb. 2, 1960 [Feb. 3, 1959], No. 3723/59. Class 100 (1). Work-feeding apparatus for feeding successively workpieces, e.g. shoe soles, from a stack to an adjacent machine comprises suction means to engage and feed the top workpiece, elevating means to raise the pile-table, and a hold-down member yieldably mounted on a carrier to engage the topmost workpiece, the yielding of the hold-down member due to upward pressure of the pile causing the elevating means to be interrupted and the suction members to be set in operation. The apparatus comprises a pile table 2 raised pneumatically by a diaphragm-operated motor to bring the topmost workpiece to a level at which it can be engaged by suction separators 4 carried by a horizontal transfer arm 3 mounted on a shaft 6 having a short vertical movement and a rotary movement so as to separate and feed the workpieces. The shaft 6 is actuated by rack-andpinion and helical cam mechanism, the rack being operated by a compressed-air piston and cylinder 8. To hold the workpiece flat and to arrest the upward movement of the pile, a hold-down member 40 is provided comprising a C-shaped metal frame 42 with an underlayer 44 of plastic material. The frame 42 carries a guide pin 58 sliding in an aperture in a fixed plate 60, another guide pin 62 engaging a hole in a carrier plate 46, and a third pin extending into a central bore in a stem 48 fixed to the carrier 46. The third pin is urged downwardly by a spring to a normal position which allows it to yield upwardly a short distance before the member 42 abuts against the underside of the carrier 46. The stem 48 has attached thereto a piston sliding in a double-acting cylinder 50 to which pressure air can be admitted at either end 54, 56. A spring- closed valve 64 is fixed to the carrier 46 and is opened by the upward movement of the holddown member 40 as it yields upwardly under the pressure of the pile and abuts against the carrier 46. In operation, when the valve 64 is opened as described, pressure air is admitted to the upper end of a piston valve 10 moving it to a position wherein pressure air is cut-off from the elevator mechanism and from the upper end of cylinder 50 and is supplied to (a) a vacuum pump to cause a workpiece to adhere to the suction cup 4, (b) the underside of the piston in the cylinder 50 to raise the hold-down member clear of the arm 3, and (c) the mechanism operating the arm 3. When the arm 3 reaches the position where the workpiece is to be released, a member associated with the piston of the cylinder 8 engages an adjustable abutment 68 to operate a trip valve 66. Actuation of this valve 66 connects the compressed air supply to the lower end of the piston valve 10 to restore it to its original position wherein the air supply is diverted from the vacuum pump, the cylinder operating the arm 3 and the lower end of the cylinder 50 to the pileraising mechanism and the upper end of cylinder 50. This allows the workpiece to be released, the arm 3 to move back under the influence of a spring to a position over the pile, and the pile-raising mechanism to operate.