ES357054A1 - Sheet feeding device - Google Patents

Abstract

A sheet-feeding device comprises at least two suction heads carried on an arm in the form of an articulated parallelogram, the movements of the arm being effected by the piston of a pneumatic cylinder bearing on one arm of a two-arm lever, the other arm forming a link of the parallelogram and carrying a roller cooperating with a fixed plate which controls the deformation of the parallelogram during its movement. General arrangement, Fig. 5.-Sheets are fed from stack 156 by suckers carried on the ends of arms 149, 150 supported on horizontal shaft 148 to the conveyer belt 139. When a preceding sheet has been processed, the conveyer releases the next sheet on to a table where the sheet is pushed into correct alignment with respect to subsequent processing machinery. Pile support, Fig. 5.-The pile 156 of sheets is preferably supported on the pallet 190 of a fork-lift truck 167 as the sheets are removed from the pile, a sensor 171 actuated by the rocker arm 147 operates the elevator mechanism of the truck to keep the top sheet at the required height. When the pile is exhausted, switch 189 operates on acoustic or visual warning switch 189 is sensitive to the presence of metal sheets, but is insensitive to non-metal materials, e.g. the wood of the pallet 190. Sheet separators, Figs. 3 and 5.-Rocker arm 147 carries a scanner 155 for sensing the height of the pile and two suckers mounted on the ends of arms 149, 150. The arm 147 pivots about cross-piece 120 of the apparatus and forms part of a parallelogram linkage, the other parts being a disc 157, an adjustable draw-bar 158 and a crank lever 161 one end of the crank lever supports a roller 160 co-operating with a fixed plate 162. A pneumatic cylinder 163 has a piston pushing against the other end of the crank lever 161, and the arrangement is such that when the piston is under pressure, the righthand end of arm 147 first rises taking the suckers and top sheet with it, and then the suckercarrying arms 149 150 rotate thus feeding the sheets into the nip of rollers 130, 152. When the cylinder 163 is evacuated, spring 170 returns the suckers to their starting position. Vacuum is supplied to the suckers during the desired periods by control systems operated by sensors. Magnetic separators 188 and blowers (not shown) aid separation. Conveying, Fig. 3.-A horizontal beam 122 supports two side members (125), (126), (Fig. 4, not shown) one fixed, one adjustable shafts 127, 128 connect the ends of the side members and carry pinions 129, 130 around which is trained a conveyer belt 139 driven by a controlled chain drive 134. A frictionless plate 144 co-operates with the underside of the conveyer belt so that sheets are fed therebetween. Tensioning roller 140 and idler rollers 143 keep the conveyer belt taut and in contact with sheets fed. The beam 122 is vertically movable on columns 123, (124), under the action of pneumatic cylinder 145 and piston 146, the arrangement being such that a sheet is first fed into the nip between roller 152 and belt 139 and the beam is only lowered when the processing machine has performed an operation on the preceding sheet. the sheet then being delivered to table 100. Registration.-A sheet is sideways delivered on to table 100 over pivotable tooth 110 spring lateral push member 111 then pushes the sheet back against the now-risen tooth 110. Rear push member 112 then aligns the sheet against front abutments 108, 109 and pincers (106), (107), (Fig. 4, not shown) of the carriage of the processing machine, e.g. a press, clamp the sheet in this position. Faulty feed.-A roller detects superposed sheets and actuates a microswitch 191 thus operating a deflector 193 which diverts the sheets into slide 194. Simplified construction.-A simplified construction suitable for use in co-operation with, e.g. a cutter, is described with reference to Figs. 6 and 7 (not shown). The table (201) of cutter is provided with a centre chain conveyer (202) carrying spaced feeding clips (203), the chain being continuously driven and co-operating with feed rollers (207, 208) through which the sheets are introduced by the suckers (215, 216).