Patent GB-694137-A (GB)
Title: A method and apparatus for trimming and grooving the ends of a plastic tube, for example ceramic drainage pipes
Inventor: WEBB CECIL EARLE
IPC: B28B21/96
Filed: 1951-02-08
Abstract: 694,137. Trimming and grooving the ends of clay pipes. BOWNE, M. S. Feb. 8, 1951. No. 3094/51. Class 87 (ii) [Also in Group XXIV]. Apparatus comprises a pair of rotary trimming and grooving tools each arranged to cut off and groove one end of the pipe. The pipe may have been formed by extrusion in conjunction with a die which forms a bell end thereon, the pipe being slightly oversize and being cut to length by the apparatus of the present invention and at the same .time being internally grooved at its ends for the reception of sealing material. Thus, in cutting off the upper end of a clay pipe 27, Fig. 13, a cutter 213 projecting outwardly from a head 32, Fig. 1, descends vertically and then, Fig. 15, rotates (the pipe remaining stationary). There are four such cutters projecting from the head and each cutter slices off a quarter of the end of the pipe. The four quarters fall away from the pipe. At the same time a sealing-cement keying groove is made in the outer surface of the pipe by a rotating roller 203. Similar operations occur at the lower bell end of the pipe, except that the groove is made on the inner surface of the bell: and the juncture between the bell and the uniform-diameter part of the pipe is chamfered off (at 147, Fig. 6). The machine comprises a base 20 supporting a stationary column 21 which carries a fixed vertically-adjustable bracket 26 in which is journaled a rotary sleeve 106. Within sleeve 106 slides a shaft 42 adapted to be clutched to sleeve 106, and this shaft carries at its lower end the four cutters 213 and a mandrel 127. The cutters are fixed on stub shafts 215 freely rotatable in head 32 fixed on shaft 42. Mandrel 127 is freely rotatable on shaft 42. On sleeve 106 is clamped a depending arm 110 which carries a lever 208 pivoted at 210; this lever carries the grooving roller 203 and is counterweighted at 212. Sleeve 106 is rotated by sprocket 104, chain 105, sprocket 97, shafts 25 and 92, gearing not shown, shaft 66, onerevolution clutch 71, gearing 64 and continuouslyrunning electric motor 24. Shaft 66 turns a vertical shaft 135 which carries a cutting wire 243, a grooving tool 248 and a chamfering tool 257. On shaft 135 is journalled a ring 141 which supports the pipe 27. The pipe is centred by pivoted rollers 31 covered with rubber or plastic material. Shaft 42, with its cutters, groover and mandrel, is raised and lowered by pneumatic or hydraulic cylinder 37 acting through links 157 and lever 109. Operation:-A clay pipe 27 is placed on the ring 141, as shown in Fig. 1, being cradled between the guide rollers 31. The pipe pushes outwardly one of the rollers, and the resulting movement actuates a switch (45, Fig. 17, not shown) to couple clutch 71 to shaft 66, which thereupon, performs one complete revolution and stops (see Group XXIV). This one revolution results in one revolution of shaft 25 and two revolutions of sleeve 106 and shaft 135. As sleeve 106 rotates, counterweight 212 is urged centrifugally outwards and roller 203 pivots inwardly and grooves the outside of the tube; simultaneously a cam 40 on shaft 25 operates reversing valve 38 whereby cylinder 37 lowers shaft 42, the cutters 213 slicing vertically through the pipe end, as shown in Fig. 13. When the shaft 42 reaches its nadir, clutch teeth 116 thereon engage clutch teeth 115 on sleeve 106, whereby the shaft and its cutters are rotated (Fig. 15), the rotary stub shaft mounting of the cutters enabling them to swivel. As cam 40 completes its one revolution, valve 38 reverses and shaft 42 rises to the full-line position shown in Fig. 1. When pipe 27 is initially placed on the ring 141, cutter 243 penetrates into the end of the bell (Fig. 1), and when shaft 66 turns thus turning shaft 135, the end of the bell is cut off; simultaneously a groove is formed on the inside of the bell by centrifugally-urged tool 248 and the bell end juncture is chamfered by tool 257. Shaft 135 and sleeve 106 rotate in opposite directions, to eliminate torque tending to turn the pipe. The parts return to rest in the Fig. 1 position, the grooving tools swinging away from the pipe. In a modification (not illustrated) switch 45 may be connected with the control system of the electric motor to release the brake and start the motor. The machine may operate on pipes having two bell ends or two plain ends. Instead of being continuouslyrunning, the motor may be started by operation of switch 45 and stopped, after one revolution of shaft 66, by a stop switch which is tripped by disc 84 forming part of clutch 71.