GB1457622A - Cutting mechanisms for metallic can body trimmers - Google Patents

Abstract

1457622 Trimming metal cans STANDUN Inc 9 Jan 1974 [12 Jan 1973] 00955/74 Heading B3W Mechanism for trimming a scrap ring from the open end of a can held on a mandrel comprises an outer cutter ring surrounding the open end and an internal cutter within, the open end which is movable radially outwardly to penetrate the can wall and circumferentially to co-operate with the ring to shear off a scrap ring, cutter ring mounting means including a reference surface which enables the cutting surface of the ring to be located in a predetermined axial position even after wear and regrinding. Feeding mechanism.-Cans to be trimmed are fed to a star wheel (52), Fig. 3 (not shown), a can being moved from a feed station 54 on the wheel to a trimming station and back by a pusher 76, Figs. 5 and 6. The pusher is mounted on a stationary vacuum tube 68 and supports a pneumatic cylinder 92. A piston 94 is fixed to the pusher 76 and a collar 78 also fixed to the pusher abuts the rear end of the cylinder. Gas is supplied to the cylinder at a pressure such that driving toggle arms (98) fixed to the cylinder forwardly, moves the cylinder 92 and, through the piston 94, the pusher 76 forward to push a can from the feed station 54 on to a mandrel 66 at a trimming station, Fig. 10. At the beginning of the feed stroke, an ejector 88 contacts the can end 46 and is moved thereby rearwardly relative to a vacuum cup 80 which uncovers vacuum passages 90 so that the cup grips the can end. After trimming, the can is returned to the station 54 still gripped by the cup 88. Towards the end of the return stroke the ejector 88 contacts the stationary vacuum tube 68 and on further rearward movement of the tube 76 the ejector engages the can end, forcing the can off the cup 88 simultaneously with the cutting off of the vacuum due to closing of the passages 90. Should the can meet an obstruction a sensor 97 detects the increased pressure in the cylinder, causes an exhaust valve 99 to open and sends an electrical signal to stop the trimming operation. A break in the vacuum grip of the cup, if e.g. a can end is split, would be detected by a sensor 72 and the feed mechanism and/or trimming mechanism shut down. Trimming mechanism.-A can 44 held on the mandrel 66 has its free end located within a cutter ring 104 and a cutter 108 located within the can end, Fig. 14. The cutter 108 is mounted on a shaft 120 freely rotatable in a frame 122. The frame 122 is mounted in a frame 114, rotatable by a gear 112, by means of a rod 124 pivoted by a cam ring 132 via a follower 128, a lever 126 and a wedge 136 to move the cutter 108 radially outwardly and inwardly as it is moved in, a circular path by the frame 114. The position of the wedge 136 is adjustable to vary the degree of penetration of the cutter 108 into the can wall. The cutter ring 104, Fig. 10, is clamped to the trimmer frame 30 with the use of a register ring 156 and a spacer ring 154. The ring 154 is of the same initial height as the cutter ring 104 and is removed with the ring 104 and ground to the same height so that the cutting face 106 of the ring 104 is always at a predetermined axial location for co-operation with the cutter 108 to sever a scrap ring 164 from the can. Scrap disposal mechanism.-When the can is pushed on to the mandrel 66 its leading end enters slots 192 in scrap positioners 190 which are moved in a circular path about the axis of the mandrel by the frame 114. A threaded cylinder 116 located within the can, constantly lubricated and rotating with the frame 114 tends to carry the scrap ring away from the can. Scrap cutters 184 located in frames 168 which also rotate with the frame 114 are moved inwards to cut the scrap ring in two by rollers 180 which are vertically reciprocable below the frame 114 to engage actuators 170 in turn. The scrap ring pieces are thrown out by centrifugal force and fall into a shoot (194) Fig. 1, not shown. The trimmed can (58) is carried by the star wheel (52) to a shoot (60), Fig. 3.