Patent GB-500784-A (GB)
Title: Improvements in or relating to apparatus for the manufacture of tubes
IPC: B29C65/00
Filed: 1938-07-04
Abstract: 500,784. Making and cutting paper &c. tubes. CELLULOID CORPORATION. July 4, 1938, No. 19731. Convention date, July 2, 1937. [Class 99 (ii)] [Also in Group VIII] Tubes are constructed by feeding flat stock to a forming means, cementing the edges of the tube and then advancing the tube to cutting and ejecting mechanism, the tube being supported during its formation by devices spaced apart from each other along the length of the tube. As shown in Fig. I, a pair of intermittently rotated rubber-covered rollers 29 draw flat stock 8 over a rubber-covered roller 24 from a roll 7, which is prevented from unwinding under its own inertia by a brake drum 17. Between rollers 29, 39 the stock is formed into a loop which is weighted by a roller 46 slidably mounted in guideways 44. As the loop shortens, the roller 46 rises until it closes a switch 48 which operates a solenoid 37 and engages a clutch to permit an electric motor 35 to rotate the rollers 29 and form a new loop ; the roller 46 then falls until it closes a switch 47 to disconnect the clutch and stop rotation of the rollers 29. The stock is kept flat until it is drawn past velvet covered or rubber members 49. A tube is then formed on a mandrel 54 which is supported by a flange 53 depending from a bridge member 52. The mandrel is either reduced in diameter at spaced intervals, or provided at spaced intervals with velvet or satin rings 55, Fig. 3. The stock is shaped into a tube by two adjustably mounted rings 59, 61, each having a series of rollers 63 disposed around the mandrel, the circumference formed by the rollers in the ring 59 being larger than that formed by the rollers in the ring 61. A lapping guide 66 ensures that one edge of the stock overlaps the other. Between the rings is a cement feeding block 67, Fig. 8, provided with a U-shaped groove 68 having a gradual slope from a valved inlet 69 to an outlet' 71. The end of the block is inserted between the overlapping edges of the tube and has an enlarged groove 72 which holds cementing material. After leaving the ring 61 and adjacent an enlarged part of the mandrel, a spring-pressed roller 84, Fig. 3, brings the edges of the tube into contact. The roller 84 may be arranged between or adjacent concave rollers 83 which draw the stock tightly around the mandrel. The laps of the seam are held until the cement is set by spring-pressed shoes 91 carried by a channel-shaped member 89. The shoes may be heated and their undersurfaces be polished metal or covered with velvet. The tube is pulled through the forming stage and pushed on to the cutting stage by an intermittently operated advancing mechanism comprising one or more pairs of rollers 112 Fig. 6, which are rotated by a variable-speed electric motor. To prevent the rollers from pushing the walls of the tube against the mandrel, each of the concaved rollers 112 bears against a convex idler roller 114 which projects through an opening 113 in the mandrel. The rollers 112 are mounted on a pair of housings 104, 105 disposed on opposite sides of the mandrel and slidably supported on a pair of shafts 106, 107 lying at right-angles to the mandrel. As the shafts are rotated in one direction, cams 115 move the housings apart against the action of springs 124 and move the rollers 112 out of contact with the tube, which is then held stationary by a pair of brakes 117, 118 mounted on the housings 105, 104 respectively, and moved into contact with the tube as the advancing rollers are moved out of contact with the tube. The shafts 106, 107 are oscillated by spring-returned belt-cranks 126 connected to the piston 127, Fig. 1, of a cylinder 128 to which air under pressure is periodically admitted by a valve 134 operated by a solenoid 135. When the solenoid is deenergized a spring 136 closes the valve 134 which opens the cylinder 128 to the atmosphere. Cutting mechanism.-The tube is cut, whilst it is stationary, by a disc knife 157, Fig. 5, disposed opposite a groove 174 adjacent a strip of velvet 55. The -knife is mounted in a stirrup 154 connected by rods 153 of adjustable length to a stirrup 155. The rods. 153 are slidably mounted in guide-ways 152 in a hub 146 rotated by an electric motor 148, Fig. 3, and centrifugal force holds a projecting pin 158, Fig. 5, on the heavier stirrup 155 against a ball 163 which engages a cam 162 carried by a plug 161 screwed into the hub 146. The knife is moved towards the mandrel by rotation of the plug 161, this being effected by a lever 167 connected with the piston 171 of a cylinder 172, Fig. 3, to which air under pressure is periodically admitted by a valve 178, Fig. 1, operated by a solenoid 177. As the lever moves to effect a cutting of the tube, it first closes a switch that operates a stopping gate in the ejecting mechanism and then opens a switch to de-energize the solenoid 135 that controls the movement of the housings 104, 105. Ejecting mechanism.-The cut tube is ejected from the machine by rubber-covered rollers 194, Fig. 14, driven by friction clutches 195 from shafts 188 rotated by an electric motor 183, the clutches only permitting the rollers 194 to rotate after the knife has severed a section from the tube. To prevent deformation of the tube, the rollers 194 bear against rollers 199 mounted in the mandrel. A further roller 209, driven through a friction clutch 213 from a shaft 205, Fig. 10, and mounted on an arm 204, is brought into contact with the tube by a connecting rod 214 when a spring-returned shaft 221 is rotated; at the same time the lever 167 closes the switch to energize a solenoid 222. Cams 232 mounted on the shaft 221 then rotate spring-returned shafts 235 to. enable forked collars 242 to operate gates 245 at the end of the mandrel. The rollers 112 advance the tube until it abuts against the gates 245. The control of the whole machine is effected by a spring-pressed finger 258 which is urged towards a groove 259 in the mandrel, and which is depressed, when the tube hits the finger, to operate a switch 257 which energizes the solenoid 177 controlling the cutter disc. Means are described for adjusting the different parts of the machine for the production of tubes of different sizes and lengths. The stock may consist of a film or foil made from or containing cellulose acetate or nitrate or of one or more sheets of an organic cellulosic derivative laminated to one or more paper sheets.