GB790212A - Improvements in or relating to methods of and machines for perforating sheet material - Google Patents

Abstract

790,212. Punching-machines. F. & H. SOUTHERN AGENCY, Ltd. July 8, 1955 [July 8, 1954; March 25, 1955], Nos. 20085/54 and 8869/55. Class 31 (2). [Also in Group XVI] A machine for punching holes in sheet material, e.g. breathing holes in plastic or other sheet material for making up into garments, comprises a feeding member having a resilient outer surface, a rotatable pin roller forming a punching nip with the feeding member at which the pins punch through the sheet material and press temporarily into the resilient outer surface of the feeding member so that the sheet material becomes impaled on the pins, an expander roller arranged on the feed side of the punching nip so as to flatten the sheet material and extend it sideways as it approaches the punching nip, and a roller on the delivery side of the punching nip co-operating with the feeding member to draw the perforated sheet material off the pins. As shown in Fig. 3, plastic sheet material 22 drawn off a roller 29 passes over an expander roller 21 through a punching nip 20 formed by a pin roller 16 and a roller 2 having a resilient covering, the perforated sheet material being drawn off the pins 17 by means of a roller 32 and wound on a roller 33 frictionally engaging driven rollers 34, 35 which may each have a resilient covering. The expander roller 21, Fig. 4, which is angularly adjustable, consists of two shafts 23 terminating in obliquely-mounted discs 24 between which extends a hollow steel roller (not shown), which may be covered with resilient material, freely rotatably mounted on the ends of the shafts 23, rods (not shown) being connected through ball joints to the drum and discs so that these rotate as a unit about the shafts 23. A series of rubber or like elastic bars 25 are connected to end-pieces 26 which are secured to the discs 24. The roller 21 may be positively driven or, preferably, rotated by engagement with the sheet material which passes over it. The roller 32 may be an expander roller. The pin roller 16 may be positively driven or, preferably, rotated by frictional engagement with the feeding member 2. Punchings are removed by a brush roller 47, Fig. 3. The rollers 16, 32 are journalled in a sub-frame 39 which is swingably connected to a frame 1 by an arm 40, a set of spring-loaded rollers 41 being secured to a cross-bar 42 on the sub-frame and engaging the upper surface of the pin roller 16 to ensure uniform punching. Alternatively, Fig. 5 (not shown), the sub-frame is supported on spring-loaded members slidable in guides in which the sub-frame is raised or lowered by means of screw-threaded members to adjust the punching pressure of the pins to a predetermined value. In a modification, the feeding member is in the form of an endless band and the shafts of the expander roller are journalled at their ends in spring-loaded cross-heads slidable in upright guides.