Patent GB-837566-A (GB)
Title: Improvements in or relating to feed devices for sheet materials
Inventor: BARSBY CHARLES RUTLAND
IPC: A21C15/00
Filed: 1957-07-30
Abstract: 837,566. Sheet-delivery apparatus. SCRIBBANS-KEMP Ltd. June 5, 1958 . [July 30; 1957], No. 24169/57. Class 100(1) A device for detecting and removing broken and defective sheets of material from a conveyer line, comprises a chamber arranged to be continuously exhausted during operations of the conveyer line and having a perforated or otherwise permeable surface adapted to co-operate with a perforated or otherwise permeable belt forming part of the conveyer line, the chamber also having an air pressure-sensitive part adapted to actuate control means to pass satisfactory sheets and reject broken or defective ones in accordance with the differences in air pressure caused by their passage on the permeable belt over the chamber. Sheets, e.g. wafer sandwich biscuits, are passed from a conveyer 4 (Fig. 1) on to a perforated belt 1 mounted above a suction box 2 having a perforated upper surface and fitted with a pivoted element 5. When a satisfactory sheet passes over the box 2 the pivoted element 5 is drawn up into the position shown in Fig. 4 and actuates a lever 24 to open a nozzle 25 of a standard pneumatic limit valve 9. In this position of the lever 24 air supplied from a pressure inlet. 19 passes through to outlet 28 to force the piston 10 of a relay valve 11 (Fig. 2) upward against the action of a spring 12. The valve 11 has a pressure inlet 21 and exhaust outlets 22, 23. With the piston 10 in the position shown in Fig. 2 air under pressure from inlet 21 is passed to connection 33 whilst connection 32 is in communcation with outlet 22. The piston 18 of an air cylinder 13 is then forced to the left as shown to operate a deflector plate 6, connected to piston rod 14. to allow the satisfactory sheet to be delivered on to a conveyer 7. When a faulty sheet passes over the box 2 the suction created in the box is insufficient to draw up the element 5 and lever 24 is left free to maintain closed the nozzle 25 under the action of tension spring 41. Outlet 28 is thus connected to an adjustable needle valve 15, the piston 10 is forced downwardly by spring 12 to connect the connection 32 with the inlet 21 and connection 33 with exhaust 23. The piston 18 is thus forced to the right as viewed in Fig. 2 and the deflector moved to the position shown in Fig. 1 for deflecting the faulty sheet into a shoot 8. The needle valve 15 controls the rate at which air escapes from the outlet 28 and thus introduces a time delay of a predetermined period before the deflector 6 is moved to its inclined position. The predetermined period is adjusted so that (a) there is sufficient time for a preceding satisfactory sheet to pass into conveyer 7 before the deflector is moved and (b) the deflector does not return to an inclined position in the event of a succesion of satisfactory sheets. When the machine is stopped a solenoid 16 is energized to raise the element 5 to the position where it actuates lever 24 to open nozzle 25 and thus to maintain the deflector 6 in the horizontal position which it assumes for satisfactory sheets. This is to prevent fouling of satisfactory sheets which may already be on the conveyer line beyond the suction box 2. Specifications 793,732 and 820,867 are referred to.