Patent GB-985793-A (GB)
Title: Method and apparatus for cutting spirally wound tubes in accurate register
IPC: B26D1/60
Filed: 1962-07-31
Abstract: 985,793. Making tubes. ROBINSON & SONS Ltd. July 31, 1962 [Aug. 1, 1961], No. 29359/62. Heading F2P. [Also in Division B5] A method of producing cylindrical containers comprises the steps of helically winding a tube with a pattern strip, moving the tube at a predetermined absolute axial speed, moving cutting means from a point remote from the position at which it is desired to cut the tube, axially of the tube, at a speed relative to the tube such that the cutting means approach a position where it is desired to cut the tube and then substantially eliminating relative movement between the cutting means and the tube when observation shows the pattern is in register with the cutting means and cutting off the tube. As shown, the tube 9 comprises one or more base layers 9b wound on a mandrel 9a by conventional means, e.g. a belt, and the pattern strip 18 includes a control mark 17 of a special ink, fluorescent patch, a magnetic marking or a physical irregularity such as a hole or slight bump, the strip being fed to the tube 9. The system at the moment when a cutting cycle is is about to begin is shown in Figs. 1 to 3 and the tube is to be cut at locations 14a, 14b distinguished by the marks 17. When the latter energizes the photo-electric cells 19 switches 22, 23 are closed, the switch 23 energizing the cell 15 and the switch 22 activating a solenoid 24 to axially displace the spool 25 of valve 26 to thereby allow fluid supplied by pumps 27, 28 to pass from the inlet port 29 to part 30 and thence to port 34 of hydraulic cylinder 5 and displace rod 7 and saw 1 axially of the tube. The pump 27 is adjusted such that the delivery thereof moves the rod 7 at the same axial speed as the tube 9 and the delivery of the pump 28 is less so that at this stage the saw moves faster than the tube. Photo-cell 19 is positioned so that the axial movement of the saw does not occur until the mark 14a has already passed the saw. As the saw approaches the mark 14a a signal from the cell 15 causes the closing of switch 33 which activates solenoid 31 to close valve 37, thus cutting off the auxiliary fluid of the cylinder 5 so that the speed of the saw is reduced to that of the tube. As the saw moves with the tube, a spring-loaded lever 41 engages a roller 42 to raise a contact 45 to bridge contacts A, this energizing a solenoid which in turn energizes a solenoid 11 to establish a holding circuit for that coil; the solenoid 11 swings the lever 10 to rock the saw into cutting engagement with the tube. After the tube has been severed, trip lever 41 engages roller 46 associated with lever 47 to raise a rod 48 and contact bar 49 which opens normally closed contacts C and breaks the holding circuit for solenoid 11. A spring 51 returns the saw to the non-cutting position thereof. Finally, a member 52 attached to the frame 8 engages a double switch 53 which resets contacts 22, 23. Resetting of switch 22 deenergizes the solenoid 24 and resetting of the switch 33 de-energizes solenoid 31, to allow the spools of valves 26, 37 to direct fluid into the port 39 of cylinder 5 and move the saw back to the starting position thereof. Relative movement between the saw and the tube may be achieved by changing the speed of the tube during the registering operation; the saw is either placed behind the desired cutting location at the beginning of the registering operation and reducing the speed of the tube during this registering period, or by placing the saw ahead of the desired cutting location at the beginning of the registering operation and increasing the speed of the tube during this registering period. In Fig. 8, the conventional tube winding head is modified and includes a main motor 102 driving bevel gears 104, 105 and by shaft 109 a differential gear assembly 107 the output shaft 110 of which transmits motion to winding belt pulleys 101, 101a. The speed of winding of the tube is increased at required times by application of rotation of a motor 119 in an appropriate rotational sense, that motor imparting rotation to the spider 116 and the bevel gears 113, 114 through a shaft 111, worm 118 and worm-wheel 117. A mechanically driven saw can be used with a mechanically or hydraulically driven tube, or an hydraulically driven tube can be used in conjunction with an hydraulically or a mechanically driven saw. A gang of saws may be employed. Specification 743,116 is referred to.