Patent GB-399209-A (GB)
Title: Improvements in and relating to sheet feeding apparatus
IPC: B65H3/36
Filed: 1932-03-31
Abstract: 399,209. Feeding sheets. POLLAK, J. E., 20, Holborn, London.-(Faber & Schleicher Akt.-Ges. ; 8, Sedanstrasse, Offenbach-on-Main, Germany.) March 31, 1932, No. 9308. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 1, 1932.] [Class 100 (i).] In a sheet-feeding apparatus which is especially applicable to feeding sheets to printing &c. machines from piles which may be in a wavy condition, and in which the sheets are fed from the piles in overlapped condition, the front edges of the sheets are acted on by suction nozzles 6 which are pivotally supported in oscillating arms 28 carried in frames 14 supported by a transverse rod 9 and by the main drive shaft 10 of the machine which is supported by frames 53, 54. The nozzles 6 seize the front edges of the top sheet of a pile 95 by suction, and lift each edge into contact with a suction roller 7, and after the suction is cut off from the nozzles 6, the nozzles are moved in the arms 28 in a direction parallel to the pivotal axis of these arms and so return to their original position to engage the sheet in a path around the side edges of the sheet previously fed. The nozzles may be moved outwards soon after having seized the edge of the sheet, so as to tauten the sheet if the pile is in a wavy condition. The nozzles 6 work in conjunction with separating and holding devices 3, 4, 5 arranged at the rear of the pile, and carried by an adjustable box 115 which can be adjusted vertically, laterally, and longitudinally to co-operate with piles of different sizes, these separating devices being operated from the shaft 10 by means of bevel gearing and an extensible shaft 43. The nozzles may be mounted so as to be adjustable vertically or angularly in a horizontal or vertical plane, and they are moved to and from the pile by cam mechanism, and the nozzles 3 are given a horizontal reciprocating movement. At the commencement of the separating operation the sheet-holding devices 4 are raised from the rear edge of the pile as shown in Fig. 12b, and the rear suction separators 5 are lowered to engage the top sheet near its rear edge. The separators 5 raise the top sheet by suction and the devices 4 then engage the pile below the separated sheet and may direct a blast of air below the top sheet to facilitate the separation. The sheet is brought into engagement with the nozzles 3, and the front edges of the sheet are engaged bv the nozzles 6 which are moved downwards and inwards as the previously separated sheet is drawn off by the rollers 7, 8. The nozzles 3, 6 are then moved towards the roller 7 and the front edge of the sheet is seized by suction apertures 64, 65, which are spaced apart to the required distance axially of the roller 7, and the nozzles 3 maintain their grip on the rear edge of the sheet to permit the sheet to be drawn taut in order to allow the nozzles 6 which are moved outwards away from the edges of the sheet after releasing the same, to move inwards under the separated sheet so that they can be lowered on to the next sheet. Finally the nozzles 3 release the sheet and return towards the nozzle 5 for a repetition of the operations, which can be effected before the complete withdrawal of the previous sheet so that the sheets advance in overlapped condition. The means for moving the nozzle 6 angularly about its pivot 31 is shown in Fig. 6, and comprises a cam 19, on a shaft 16 driven from the shaft 10. The cam 19 oscillates a segmental gear 33 geared to the pivot 31, and similar cams on the shaft 16 oscillate the arm 28 and reciprocate the pivot 31 axially. For dealing with stiff sheets the nozzles 6 can be put out of action and the sheets are fed solely by the devices 3, 4, 5 acting on the rear of the pile which is arranged at a higher level than for flexible sheets. The roller 7 is preferably constructed as shown at Fig. 8, and comprises an outer perforated tube 7 formed of two parts connected by a projection 52 and driven from the shaft 10 by gears 38, and a spur wheel 40 to the hub of which the tube 7 is soldered. The tube 7 rides on bushes 58, 59 fixed to pivots 55, 56 supported in the frames 53, 54 and on a central bush 61. Within the tube 7 and independently rockable or rotatable are the two suction nozzles 64, 65 formed in cross-shaped bodies 66, 67 which can be adjustable axially by screws 68, 69 to suit sheets of different width. The bodies 66, 67 are rotatable with the pivot 55 which is oscillated by a cam 80, lever 82 and link 83. The nozzles are connected by telescopic tubes 74, 75, and apertures in the central shaft 57 on which the nozzles are adjustable, to fixed tubes 76, 77 connected to an air pump. The action of the air pressure is limited to the extent of the nozzles 64, 65, and this may be further limited as shown in Fig. 11, by arranging a spring- pressed segmental body 86, made of compressed carbon similar to that used for commutator brushes, or other suitable material, within the member 66, the suction effect being in this case limited to the width of a slot 91 in the body 86 which itself acts as an antifriction device to permit easy movement of the roller 7. When the sheets are advanced in overlapped condition the nozzles 64, 65 may be stationary throughout, and may extend from the front of the pile to the line of contact with the roller 8. In some cases only one of the nozzles 6 is given a lateral reciprocating movement. The roller 7 may be fitted with air blast nozzles for blowing the sheet away from it. One central suction nozzle 3, or 5 may replace the two nozzles 3, 5, or these nozzles may be dispensed with entirely.