GB1234271A - - Google Patents

Abstract

1,234,271. Separating sheets. CAMCO (MACHINERY) Ltd. 23 Dec., 1968 [8 Jan., 1968], No. 1151/68. Heading B8R. Apparatus for separating sheets from a stack comprises vertically movable suction grippers engaging the top sheet, clamping means operable to engage the remainder of the stack below the sheet being separated, a continuously-operating suction feed drum receiving sheets from the grippers, and means sensing the pressure in the suction line connected to the grippers operable to detect pressure changes caused by engagement of a sheet by the grippers and to control the movement of the grippers and the clamping means. General arrangement, Fig. 14b.-A stack 67 of sheets is supported on a table against a front lay 68, the table being vertically movable by an electrically-operated ratchet mechanism in response to a feeler 33. A head assembly 10 is movable along bar 11, to which it may be adjustably clamped, and supports suction grippers 30 and clamp plates 36, both linked to a rocker shaft 15. A rotating suction drum 64 completes the feed, and air blasts act between the separated sheet 5 and the rest of the stack, and also on the rear face of the stack, the various operations being controlled by fluid pressure changes, in such a way that the mechanism is self-contained and the timing depends only on the speed of rotation of drum 64. Control circuit and operation, Fig. 13.-Initially, the stack is raised until the top sheet engages the feeler 33 and suction grippers 30. On application of suction through restrictor 101, coupler 76, and conduits 28, the top sheet is gripped, and the resulting increase in suction is communicated via tapping port 103 to response valve 52, which, in turn, allows compressed air from branch 107 to be supplied by line 109 to cylinder 19. Movement of piston 18 to the right as viewed in Fig. 13 pivots link 16, which is connected to the rocker shaft 15, and thus lifts suction grippers 30 with the attached sheet 5 away from the stack, and pivots clamp plates 36 on to the stack. Simultaneously, the piston valves (47) (Figs. 9, 10, not shown) of blow jets 44 are allowed to rise, and compressed air passes from coupler 104 and 106 through the jets between the raised sheet and the stack, thus lifting the front end of the sheet into contact with drum 64, which is rotating continuously, and draws the sheet forward, i.e. to the left as viewed in Fig. 14b. This forward movement causes the grippers to tilt about internal pivots (29) (Fig. 8, not shown) and lines 28 are vented to atmosphere; the response valve 52 senses this pressure change, and applies compressed air through line 108 to the righthand end of cylinder 19, thus returning the rocker shaft 15 and associated clamping and gripping means to the initial position.