Patent GB-703981-A (GB)
Title: Improvements in and relating to the manufacture of helically wound tubes
IPC: B31C3/00
Filed: 1948-05-12
Abstract: 703,981. Machines for making paper tubes. ROBINSON, E. B. May 12, 1949 [May 12, 1948], No. 13051/48. Addition to 653,613. Class 99 (2). [Also in Group VIII] In the machine for making paper tubes described in the parent Specification in which pattern-bearing strip material is wound helically on a mandrel 2 by a belt 7 and a cutter device 11 is reciprocated alongside the tube as it comes off the mandrel and moves transversely of the tube at intervals to cut it into lengths, and in which the cutter is controlled in cooperation with control marks or irregularities on the strip material to ensure that the cuts are made between patterns, the cutter is reciprocated continuously without a variably-controlled pause, and cutting is controlled by automatically adjusting the traversing relationship between the cutter and the tube. As shown in Fig. 4, the tube is supported, during cutting, by a mandrel 9 extending from the mandrel 2 and movable axially thereof by a rod 10 (shown in Fig. 6) connected to a cutter carriage 19 by a rod 10a. The carriage 19 is traversed by a cam 15 rotated through a variable-speed gear 12 or by a variable-speed motor. The cam 15 rocks a lever 16 about a fulcrum 18 adjustable for tubes of different lengths, the lever having a slot 22 engaging a pin 20 on the carriage and a slot 116 engaging a pin 117 riding in a slot 120. The cam 15 is so shaped that the carriage 19 moves at substantially constant speed for the middle part of its forward traverse and restarts its forward traverse immediately or after a pause of constant duration. If the speeds of the tube and the cutter carriage are not in synchronism, this is detected by a photo cell device 24-26, which, through a switch 27, amplifier 28, commutator 29, relays 30 and a reversible motor 14<SP>1</SP>, adjusts a speed-control device 35 controlling the variable-speed gear 12. In a modification, Fig. 7 (not shown), the motor 14' controls a differential gear in the drive to the unit 12 whereby when the motor is driven for a correction an increase or decrease of speed of short duration is applied to the unit. The differential may be connected to the output shaft of the unit and may be applied to the tube winding mechanism or to both the tube winding and the cutter-traversing mechanisms. In a modification of the device of Fig. 7, Fig. 8 (not shown), the motor 14<SP>1</SP> is connected to the unit 12 as well as to the differential whereby an adjustment of the speed of traverse of the cutter is effected also. Fig. 6 shows mechanism for varying the return-traverse speed of the cutter and the traverse speed of the tube. A lead screw 39 fixed to the rod 10 works in a nut 40 rotated in the direction for forward stroke of the cutter by a clutch 43 driven by a chain 49 from a motor 52 and engaged by means of a lever 44 actuated by a solenoid 47 controlled by a limit switch 61 closed by a cam 57 on a bar 56 rigid with the rod 10. The nut 40 is rotated in the opposite direction by a clutch 42 driven from the motor 52 through gears 55, a variable-speed gear 54 controlled from the photo-cell device and a chain 48, and is engaged by means of a lever 45, solenoid 46 and switch 58. The tube-winding belt 7 (shown in Fig. 4) is driven at variable speed through gearing 64. According to the Provisional Specification (1) the cutter mechanism may be driven by hydraulic jacks controlled by a valve actuated from the moving tubing, and (2) power driven mechanism for traversing the cutter mechanism may be controlled by engagement of the free end of the tubing with a feeler traversed by the being-formed tubing so that the speed of the cutter mechanism synchronizes with that of the tubing. Specifications 653,614, 653,615 and 653,616 are referred to.