GB843659A - Improvements in or relating to sheet folding machines - Google Patents

Abstract

843,659. Folding sheets &c. ARMSTRONG & CO. Ltd., J., and SMITH, J. Nov. 28, 1958 [Sept. 5, 1957], No. 28085/57. Class 42 (2). A machine for folding bed-sheets &c. comprises a belt conveyer 4, Fig. 1, on which the sheets are fed in succession so that they hang down on each side of the belt, and means for holding back the forward edge of each sheet so that, by the conveying action of the belt, that edge becomes progressively doubled back, and for subsequently releasing that edge so that the doubled sheet is thereafter conveyed by the belt while still hanging down on each side thereof. Sheets delivered by a calender 2 are conveyed by narrow belts 3, 4, supported on plates 44, 45. The forward edge of a sheet is guided by fixed guide members 12, Fig. 4, between upper and lower grippers 7, 10 carried by bridge-shaped members 5, 6 rotatable about an axis X-X. Member 6 is frictionally braked at 25, 26, while member 5 is connected by a trunnion 15 to a sprocket 19 engaging a chain 20 connected at one end to the piston-rod 21 of a pneumatic cylinder 22, Fig. 1, and at the other end to a return-spring 23. When the second of two electric switches 39, 40 is closed by the forward edge of the sheet, a solenoid is energized and compressed air is supplied to cylinder 22. Member 5 is thereby swung to the dotted line position, Fig. 1; firstly it grips the edge of the sheet against gripper 7 and then carries member 6 with it, thus folding back the leading edge of the sheet. Switch 40 is opened, but a pneumatically-operated holding switch maintains the circuit. When the trailing edge of the sheet passes switch 39 the latter opens, the circuit is broken, and cylinder 22 is exhausted. Member 5 thereupon is swung back to the full-line position; firstly it separates the grippers 7, 10, releasing the doubled-back portion of sheet which falls into the portion on the belt 4; thereafter a flange 11 on member 5 engages member 6 to carry the latter back with it. The doubled sheet proceeds along belt 4 to a second transverse-folding mechanism similar to the first. The twice transversely-folded sheet is delivered on to a shoe 13 hanging down on each side thereof whence it can be removed by hand again doubled by a longitudinal fold. A cover. 46 carries idler rollers 47 which press against belt 3 to provide a grip for the sheet. The belts may each comprise a single belt, or a number of narrow belts side - by - side which may consist of wires or chains. The air cylinders may be replaced by hydraulic cylinders or solenoids.