Patent GB-743116-A (GB)
Title: Improvements in or relating to tubes formed by helical winding
IPC: B31C3/00
Filed: 1951-02-09
Abstract: 743,116. Cutting tubes. ROBINSON, E. B. May 9, 1952 [Feb. 9, 1951], No. 3157/51. Class 31 (1). [Also in Groups XXVIII and XXIX] In a machine for the production of paper &c. tubes by winding strip material helically on a mandrel 19, Fig. 1, to form tubing which is cut into lengths by cutting-apparatus traversed longitudinally of the tubing and moved laterally into cutting position during the forward stroke and withdrawn before the return stroke, the longitudinal movement is effected by fluidpressure operated mechanism controlled by the travel of the tubing or by marks or irregularities on the strip material. As shown, the cutting- apparatus comprises two banks of cutters 4, 5 mounted on a carriage 1 supported by rollers 3, the bank 4 being carried by a slide 7 connected by a rod 45 to rocker arms 38 carrying the bank 5. Traverse of the carriage is effected by a hydraulic ram 58, Fig. 7, and lateral movement of the cutters by cams 20 which move the slide 7 inwardly against spring action and are fixed to a shaft 22 rotated from a crank 31 connected to the rod of a pneumatic, or, according to the Provisional Specification, hydraulic, ram 30. The ram 58 is controlled electrically, and the ram 30 is controlled from the carriage, both as described below. Hydraulic mechanism for traversing the carriage. A variable-delivery pump 65, Fig. 13, fed from a reservoir 69 through a filter 70 supplies fluid to the ram 58 via a relief valve 72 and a valve 73. At the beginning of a cycle, the valve 73 is in the position shown, under the influence of a weight 74, and the ram is fully extended. The fluid then passes through the valve 72 and a cooler 81 to the filter. On energization of a solenoid 80, the valve 73 is raised, the cylinder side of the ram is connected via passages 78, 76 to the cooler, the ram enters the cylinder and the carriage moves forward on a cutting stroke. Part of the fluid passes through a needle valve 172 during acceleration of the carriage, and when constant speed is reached the fluid pressure falls below the setting of the valve 172 which closes whereupon the ram takes the whole of the delivery. At the end of the stroke, a striker on the carriage operates a switch to de-energize the solenoid, the valve drops, and the cylinder side of the ram is connected both to the pump delivery and to exhaust from the rod side of the ram, thus providing a quick return. A cushioning effect is provided by a chamber 82 in which fluid is trapped and escapes through a valve 83. Pneumatic mechanism for operating the cutters. A valve 32, Figs. 7 and 21, controls a supply of compressed air which enters by a port 303. Pipes 304, 305 are connected to the cylinder and rod sides of the ram respectively. The valve is operated by a lever 34 pivoted to the valve and engaged by a striker 308 adjustably clamped to a rod 101 extending from the cutter carriage 1. Electrical control. A photo-electric cell detector is situated so as to be influenced by marks &c. on either side of the strip or on the inside or outside of the tubing. The circuit described is identical with that described in Specification 743,115. Specifications 653,613 and 653,616 also are referred to.