Patent GB-897773-A (GB)
Title: Improvements relating to sheet feeder apparatus
Inventor: SOLOMON JACOB
IPC: B65H3/08
Filed: 1958-12-15
Abstract: 897,773. Feeding sheets. GESTETNER Ltd. March 1, 1960 [Dec. 15, 1958], No. 40439/58. Class 100(1) A device for separating sheets one by one from the top of a pile 13 comprises a pneumatically operated device for holding down the remainder of the pile of sheets on for separating the top sheet of a pile and a support 14 whilst the top sheet is being lifted, means controlling pneumatically the position of the support 14 as sheets are lifted from the pile thereon, and a sheetlifting piston and cylinder arrangement which is located above the support and in which the cylinder 49 has on opposite sides of the piston upper and lower chambers and the piston is biased towards an upper position and has a depending piston rod 51 carrying at its lower end a sucker cap 53, a duct which is in communication with the upper cylinder chamber extending through the rod 51 and cup 53 and opening to the atmosphere at the suction face of the latter; the arrangement is such that when the chambers are connected to a vacuum source the piston moves downwards against its bias because the upper chamber communicates with the atmosphere through the duct, but when the sucker cup engages a sheet of paper and the duct is thereby closed the piston moves upwards to lift the sheet from the pile. The machine frame comprises sideplates 10, 11 in which is journalled a shaft 12. A sleeve 15 is rotatably mounted on the shaft 12 and carries a twin-arm unit 16, 17, of which the arms are joined by a handle 18. The arm 17 is of telescopic construction, having an inner member to which the cylinder 49 is secured. The outer end of the inner member has a slotted head 66 carrying a roller 67 engaged by a cam 68 on the shaft 12. Suction is applied to the chambers in the cylinder through a hose 62. The hose 62 is supplied with suction at the appropriate times by means of a rotary distributer valve 63 connected to the shaft 12. As the shaft 12 rotates the suction cup 53 descends and picks up the top sheet from the pile13; the piston and cylinder assembly is then reciprocated horizontally by means of the cam 68 so that the leading edge of the sheet is fed between a driven shaft 74 and a roller 70 which transfer it to a tape conveyer 73. Guides 76 engage the side edges of the sheet as this is done. The conveyer 73 feeds the sheets to a printing or other machine. Separation of the sheets is facilitated by a device 19 which is secured on the arm 16 and is longitudinally adjustable thereon. The housing 21 of the device 19 carries an air blower 22 which is connected to the distributer valve 63 and which blows air at the edges of the sheets at the top of the pile 13. A pair of hollow legs 25, having feet in the form of nozzles 27 is mounted for vertical reciprocation in the housing 21, such reciprocation being effected by a pneumatic jack 28, actuated by the valve 63, and a bell-crank lever 29. The nozzles 27 engage the second sheet in the pile and hold it down as the top sheet is being lifted by the sucker cup 53, air being simultaneously blown through the nozzles to facilitate separation of the top sheet. When the pile has been reduced in height by a predetermined amount the nozzles 27 have to descend so far to engage the second sheet thereof that the piston of the jack 28 opens a spring-biased ball valve and thereby connects the air pressure inlet 33 of the jack to a branch 34 coupled by a hose 35 to a second pneumatic jack 36 mounted on the side plate 10. Operation of the jack 36 withdraws a stop 37 from engagement with a pivoted arm 38 which is then oscillated by a cam 40 on the shaft 12. A pawl 41 carried by the shaft 38 rotates a ratchet 42 which operates lifting mechanism for raising the support 14. The support can also be raised manually by means of a handle 45. A brush 46 is carried by the housing 21 and extends between the legs 25 to prevent the picking up of more than one sheet at a time. The back corners of the top sheet on the pile are held by small counter weighted balls 47 fixed on rods 48, which balls prevent the paper from being blown out of position by the air blast. The top of the pile 13 is prevented from slipping rearwards by downwardly directed strips carried by the rods 48. The front edge of the pile abuts against a fence 75 which is pivoted at its lower end and oscillates between a vertical position and a position inclined to the vertical so as to allow a sheet carried by the sucker cup 53 to pass over the top thereof. The oscillating movement serves to keep the pile even.