GB888350A - Improvements in and relating to plants for the stacking of sheet metal - Google Patents

Abstract

888,350. Endless conveyers. UNGERER, F. Jan. 25, 1960, No. 2597/60. Class 78 (1). [Also in Group XVI] In a plant for the stacking of sheet metal the sheets are held by suction on the underside of an endless depositing conveyer belt before being dropped on a stack and suction heads are provided on the upper side of the lower strand of the conveyer, those suction heads which are situated above the stacking place and act on the sheet metal through the belt, being controllable by rays in dependence on the position of a sheet to be dropped. As shown, an endless conveyer belt 3 is driven by an electric motor 4 and has series of holes 23 therein arranged in longitudinally extending bands 25. The holes 23 flare outwards towards the outside of the belt 3. At the upper side of the lower run of the conveyer are mounted suction heads 6-11. The heads 6 form a series extending transversely of the conveyer belt and during operation of the machine exert continuous suction. There are three heads 9, Fig. 2, disposed transversely across the belt 3, one above each of the bands 25. Located outside and between the heads 9 over the parts of the belt 3 which are free from holes are further suction heads 28, 29, which exert suction continuously. The suction heads 7, 8, 10, 11 are arranged similarly to the heads 9. Metal sheets 16 are fed successively by a conveyer 15 to the lower run of the belt 3 where they are picked up and held in contact with the belt 3 owing to the suction exerted by the several heads 6-11. When a sheet reaches the position 16<SP>1</SP> its leading or trailing edge is detected by means sensitive to visible or invisible rays, e.g. a photo-electric cell, which actuates valves in the supply lines of the heads 7-11 so as momentarily to disconnect them from a source of suction and connect them to a supply of compressed-air. The sheet 16 is thereby detached from the belt 3 and, owing to its forward momentum, describes a parabolic curve in falling on to a receiving table 18 having a resilient abutment 19 which arrests the leading edge of the sheet. The actuation of the valves may be so rapid as to allow a longitudinal spacing of the metal sheets on the belt 3 of as little as one inch and there may be a delay, of variable length, between the sensing of a sheet edge and the actuation of the valves. The suction heads 28, 29 prevent sagging of the belt 3 and prevent it from flapping when compressed-air is blown through the heads 7-11. Instead of having holes the belt 3 may consist of an airpermeable fabric, e.g. wire gauze, in which case the suction heads have lips of resilient material which engage the belt. In modifications, the metal sheets are held away from the belt 3 by projections on the outside of the belt so as to permit a more rapid separation of the sheets from the belt. The projections may be in the form of individual lumps or longitudinal strips and may coincide with the holes 23.