Patent GB-1078931-A (GB)
Title: Sheet feeding device
Inventor: SCHWEBEL ADOLF
IPC: B65H3/40
Filed: 1964-08-27
Abstract: 1,078,931. Feeding sheets. MABEG MASCHINENBAU G.m.b.H. NACHF HENSE & PLEINES G.m.b.H. & CO. Aug. 27, 1964, No. 35134/64. Heading B6B. Sheets are separated from the top of a stack 17 by two or more pneumatic heads, and are fed away in overlapping form by the action of air blasts and the engagement of the heads with feed rollers 44. Only two pneumatic heads 1, 2 are shown in Fig. 1, but three such heads are employed, each being connected alternately to sources of suction and compressed air through a rotary valve associated with a Geneva mechanism (Fig. 8, not shown). Each head 1, 2 is moved in a substantially circular path 66 by the engagement of its support 7 with a vertically adjustable cam 40. The support 7 is driven upwardly against the action of a compression spring 10 arranged between the head and the support 7. Tubes 4, 5 supporting the heads 1, 2, respectively, are lengthwise slidable in the supports 7 against the action of the springs 10, and are adjustable vertically and angularly in the supports by nuts 13 and brackets 18 having screw means 21. The two supports 7 are pivoted on studs 27, 28 respectively, and arms 24, 25 also pivoted on these studs and on further studs 30, 31, engage the supports 7 through loaded springs 34. The two sets of studs 27, 28 and 30, 31, respectively, are arranged to be rotated about axes 33a, 33a by gears 33, 33b, whereby the supports 7 are reciprocated against the springs 10 and urged by the springs 34 against the cams 40, and the heads 1, 2 are caused to follow the substantially circular paths 66. Each pneumatic head 1, 2 has a pressure roller 46, 48, respectively, which is urged bodily by a spring to protrude above the top of the head, and this roller engages a driven feed roller 44, when the head rises, to grip a separated sheet and feed it towards a table 50. Compressed air is supplied to a pipe 51 having one branch 51 directed against the top sheets of the stack 17 and directed upwardly at 56, and a second branch 53 directed at 55 beneath sheets being lifted from the stack. A sheet deflecting roller 49 is driven from the roller 44 through an idler roller 49a. In operation, using three pneumatic heads (1, 2, 3, Figs. 3-6), the pneumatic head 1 disposed above the stack 17 is connected to a source of vacuum and rises with the top sheet of the stack. The next head 2 moves beneath the first head towards the stack to pick up a sheet, and the first sheet is dropped over the second head 2 by supplying compressed-air to the first head 1. At the same time, the third head (3) has blown a sheet over the head 1 and this sheet is now being forwarded by the feed roller 44 and the roller protruding above the head 1. Thus, each head lifts a sheet, releases it over a succeeding head, and feeds a sheet previously lifted by co-operating with the roller 44. Each lifted sheet is forced against the deflecting roller 49 and floated by the air blasts 55, 56 to assist separation. Each pneumatic head 1, 2 &c. is vented to atmosphere at the top of the head at (62, Fig. 7) through a main passage (71) and a vent passage (60), and the main passage can be closed by a ball valve (59). When the mouth (16) of the head is sealed by a sheet, the suction buildup in the head closes the ball valve against the action of a spring (58), and the sheet can be lifted and separated. However, due to the vent (60), a sheet covering the passage (62) is held there by suction, and the ball (59) is then released to allow full suction to act on the sheet covering the head, and the sheet is pulled against the head with sufficient force to depress the pressure roller, such as 46, against its spring. Thus, each head is provided with two suction and two blowing ports for the attachment and detachment of sheets, and the valve arrangement ensures that the apparatus, will function when lifting the first sheet. If during the operation a sheet is misplaced and does not cover the passage (62) in a head, sheet separation will fail.