Patent GB-1484078-A (GB)
Title: Wrapping machines
IPC: B65B51/10
Filed: 1975-05-22
Abstract: 1484078 Seaming non-metallic sheet material; cutting apparatus F M C CORP 22 May 1975 [5 Sept 1974] 22064/75 Headings B5K and B4B [Also in Division B8] A sealing, crimping and severing assembly C for incorporation in a wrapping machine 20, Fig. 1, comprises two opposed co-operating rotary heads for crimping and severing sheet material T and which are mounted on respective rotary shafts 30, 32, Fig. 14, one head having a blade 104 mounted in a slot 98 formed therein for movement relative to this head and the other head having a recess 38 to receive part of the blade 104 when it is in an outer position with respect to its slot. In the machine 20, Fig. 1, spaced articles A are fed by pushers on a conveyer 22 and a plastics web W from a spool S is wrapped therearound by a shoe 26 to form a tube T beneath which the overlapping margins of the web are sealed. Gripping belts 28 advance the tube T to a crimping, sealing and severing head C which crimps, heat seals and severs the web between adjacent articles A. Individual packages P are discharged by a conveyer D. The head C comprises counter-rotatable shafts 30, 32, Figs. 3 and 14, provided with crimping and sealing jaws 34, 36 having circumferential crimping ribs (128), (130), Fig. 2 (not shown), and heated by electric cartridge heaters 130. Intermeshing gears 50, 52 rotate the jaws 34, 36 in timed relation to each other and to the web W. The shaft 30 is displaceable upwardly against the action of springs (54), Fig. 4 (not shown), if a mistimed article is present between the jaws 34, 36 when they close together. A cam follower assembly 62, Figs. 3 and 17, is secured to the shaft 30 and includes rollers 64 biased outwardly into rolling engagement with a face cam 58 circular except for an inwardly directed lobe 60. Each roller 64 is attached to an arm 66 having a fork receiving a cross head 76 of a link 78 through which passes a tension rod 80 secured to a head 82<SP>1</SP> pivoted to links 84 having bell-cranks 88 pivoted thereto by pins 90. Tension springs 92 act on the links 84 to urge the rollers 64 into engagement with the cam 58. The bell-cranks 88 are mounted on a fixed pivot stud 96 and have cutting blades 104 pivoted thereto by pins 102. Each blade 104, Fig. 10, has a plane surface 108 and a bevelled surface 110 and inclined cutting edges 116 so that a zig-zag severance cut (Z), Fig. 2, and 13 (both not shown), is formed. To support the entubed articles A when the jaws 34, 36 are open, the shaft 32 is provided with two arcuate spacer blocks 142.  In operation, when the jaws 34, 36 are open the blades 104 are held retracted in their slots 98 and, as the lowermost blade 104 approaches vertical alignment with the uppermost recess 38, the lower roller 64 begins to ride up the cam lobe 60. Thus, the lower arm 66 moves the lower rod 80 to the right, Fig. 18 (not shown), so that the lower boll-cranks 88 swing downwardly to project the blade 104 into the recess 38 to sever the web W as it is simultaneously sealed and crimped. As the roller 64 leaves the lobe 60, the tension spring 92 retracts the blade 104 and maintains the roller 64 in engagement with the cam 58.