GB785414A - Sheet feeding apparatus - Google Patents

Abstract

785,414. Feeding metal sheets. AETNASTANDARD ENGINEERING CO. Jan. 18, 1956 [April 20, 1955], No. 1695/56. Class 100(1) Metal sheets S are separated from a pile P in a support 4 by an oscillating sucker 25<SP>1</SP> until they contact rotating magnetic rolls 7, 9, whereupon suction ceases, and the sheets are fed upwardly by the rolls between guides 14, 15 to pairs of feed-off rolls 10, 11 and 12, 13 for movement to a tinning, galvanizing or other machine. As shown in Fig. 3, there are three piles P, and three pairs of suckers carried by arms 16-21 secured on a single pivot shaft 5, the arms all being attached together by a tierod 22 connected to and oscillated by the rod 29 of a piston in a fixed cylinder 27. The working fluid is allowed to enter the cylinder on either side of the piston under the control of a four-way valve V operable against the action of a return spring by a solenoid M which is energized when a sheet S completes an electric circuit through one of the contactors 87, 89, or 91 on the shaft 8 of the roll 9. Suction to each sucker 25<SP>1</SP> is established through a hose 44, a header pipe 45, hose 48, and pipes 50, 49 connected to a fixed cylinder 51. A piston 52 in this cylinder is secured to a rod 53 having a pin-and-slot connection With a vertical arm 55 keyed on the shaft 5, whereby the piston is moved to the right by the oscillation of the sucker arms 16-21 to produce suction at the suckers 25<SP>1</SP>. An adjustable member 62 on. an extension 55<SP>1</SP> of the arm 55 opens a relief valve 59 to release the sheets S only when the sheets make contact with the magnetic rolls 7, 9. A pin on the arm 55 is adapted to close a reverse limit switch 65 after a sheet is released, but this has no effect on the circuit until a sheet S leaves the rolls 7, 9. The same pin on the arm 55 is also adapted to open a forward limit switch 67 to de-energize the solenoid M and allow the valve V to be returned by the spring to the position shown in Fig. 2. Each sucker 25<SP>1</SP> is formed on a head 25 carried by a tube 24 slidable, against the action of a spring 26, in a bracket 23 secured to the operating arm, such as 16. The spring 26 allows the arm 16 to continue to move after a sheet has been engaged by the sucker, allows time, on the reverse movement of the arm, for suction to build up in the sucker, and compensates for the depletion of sheets in the pile P. The electric circuit described and shown in the Specification includes two transformers to supply current at reduced voltages, and a series of relays and switches, and ensures that (a) the suction separator arms 16-21 will remain retracted until the sheets have left the magnetic rolls 7, 9; (b) even though the main switch and starting button have both been depressed, the apparatus will not function unless there is a supply of low voltage current to energize a starting relay; and (c) prevents rapid vibration of the separator arms in the event of a sheet slipping:from contact with the contactor rings on the magnetic rolls 8, 9.