Patent GB-313244-A (GB)
Title: Improvements in pneumatic mechanisms for feeding sheets
IPC: B65H5/10
Filed: 1928-03-31
Abstract: 313,244. Marks, E. C. R., (Spiegel, May, Stern Co.). March 31, 1928. Stencils. - A sheet - feeding mechanism, which is described in connection with a machine for making stencils. comprises a sheet support formed with a series of perforated surfaces which normally support by suction a long sheet of paper, and, as the support is moved to a position below a gummed stencil frame, the vacuum is broken in a certain part of the support and a part of the sheet, which is severed by cutting, is raised into contact with the stencil frame by a reciprocating suction-nozzle which is shaped to pass through the frame. An air blast is directed through the certain part of the support to assist in the separation of the sheet and in its application to the stencil frame. Two sheet supports 4 operating alternately are given a step-by-step movement by rack-andpinion mechanism towards the right in Fig. 1, and at the commencement of each movement a long sheet is placed on the support, and is held thereto by suction in foraminous plates 15 arranged above suctionchambers 12 and formed with apertures arranged in a group of similar contour to that of the cut stencil sheet. The chambers 12 communicate with a suction chamber 13 in the support connected to the inner suction tube 17, of a double tube 17, 18 between which tubes compressed air is introduced by a flexible pipe 35 arranged near a similar suction pipe 33. The tubes 17, 18 are connected to and operated by reciprocating fittings 23 operated by a cam 30 on shaft 78, and valves 19, 20, 21 on the conduits assist in controlling the air pressure in the chambers 12; 13. The valve 19 confines the effect of the suction in chamber 13 to chambers 12 to the left of valve 19, and valves 19, 20 form a chamber in constant connection with the air conduit 18, whilst valve 21 limits the outflow of air to the adjacent chamber 12. The valves move with the table as this moves, to the right, and return to the left as the table is held stationary. The air pressure in pipe 35 is governed by a reciprocating valve 62, Fig. 5, which can connect a pressure chamber 56 supplied by a pipe 57 with a chamber 58 connected to pipe 35. The valves 62 for the two tables are operated by a pair of bell-crank levers 49 which are oscillated by a cam 38 engaging rollers on the levers 49. The levers 49 also operate sliding valves to control the air pressure in the suction conduits 33. The stencil frames 3 are guided on rails 2, and the cut sheet, when released from the suction of its chamber 12, is drawn into contact with a gummed frame by a reciprocating nozzle 69 on a suction tube 64 operated by a lever 75 and cam 77 on shaft 78. The tube 64 terminates in a nozzle 69 shaped to pass through the openings in stencil frames 3. Two suction tubes 64 are provided to cooperate with the corresponding feed tables and they are latched for a series of operations to a reciprocating head 65 by means of latches on shafts 83 operated by a cam 84 on shaft 39 and lever-andlink connections. When the sheet on one table has been fed completely, the corresponding nozzle 62 is held in raised position, being unlatched from the head 65, and the other nozzle is latched to head 65, and feeds the cut sheets to the stencil frames fed to a different position on the guides 2.