Patent GB-1303056-A (GB)
IPC: B65G13/00
Filed: 1969-09-19
Abstract: 1303056 Feeding and delivering sheets PILKINGTON BROS Ltd G H BRANCH and J E Hall 16 Sept 1970 [19 Sept 1969] 46409/69 Heading B8R [Also in Division C1] In apparatus for transferring sheet material, e.g. glass sheets, from a first location, e.g. a roller conveyer 25, Fig. 11, to a second location, e.g. a roller conveyer or a stack receiving table 28 or a plurality of such tables (31), (32), (33), Fig, 12 (not shown), suction from a suction means mounted above a substantially horizontal transfer path is created in the vicinity of rollers 3, spaced along the transfer path so as to hold the upper surface of each sheet in engagement with the rollers. A suction chamber 5 may be located between each pair of rollers 3, each chamber having holes or slits through which the vacuum is applied, or the rollers may be mounted in a common suction hood (22), Fig. 7 (not shown), or in a compartmented hood, the compartments being defined by partitions (18a), Fig. 5 (not shown), or by flexible flaps (24b), Fig. 8 (not shown), engaging each roller. Each roller may have rubber tyres thereon. In a stacking operation, a sheet is fed by conveyer 25, which may be raised, to the transfer apparatus 26 and is held against the rollers 3 by suction, these rollers delivering the sheet to a position, e.g. as defined by a stop 30, above the stack table 28. Suction may then be cut off, or rollers on a vertically movable frame 29 may be actuated to prize the sheet off the transfer apparatus, the sheet then dropping on to the table 28 which is lowered incrementally. Air jets and mechanical pushers (70), Fig. 15 (not shown), may assist in correct positioning of sheets in the stack. Sheets may be stacked according to size, as detected by a device (34) sensing the leading and trailing sheet edges, in separate stacks (31), (32), (33), the device (34) actuating the prising rollers or cutting off the suction. Faulty sheets may also be detected and stacked separately. In the embodiment shown in Fig. 16, all rollers 3 except the first roller 3a are compartmented by flexible flaps, roller 3a being in a compartment communicating with a main suction hood via a relatively large, valved aperture 81, the other compartments communicating via smaller apertures in the hood roof. A sheet bridging the gap between roller 3a and its neighbour causes suction to be applied through each small aperture but when the trailing edge clears the gap, suction is preferentially applied through the large aperture 81 only, causing the sheet to drop to the table 57. Valves 53 can be opened to adjust the length of the transfer path according to sheet length. Alternatively, if valve 56 is closed, the suction is retained at each of the smaller apertures and the sheet continues past the stack. In a similar arrangement, Fig. 17 (not shown), the valve (87) is associated with the first roller (3b), the other rollers being mounted in a common hood (22) and sheet size adjustment being effected by a movable baffle (92). The apparatus may be used to separate sheets from a stack by driving the rollers and stack table reversely, or may be used to temporarily stack sheets intermediate their travel on conveyers (13), Fig. 1 (not shown).