GB664870A - Improvements in screw-threading machines - Google Patents

Abstract

664,870. Screwing-machines. W. J. L. (MACHINERY), Ltd. Sept. 20, 1950 [July 18, 1949], No. 18876/49. Class 83 (iii). [Also in Group XXIII] A manually-portable power-operated screwcutting machine, particularly for operating on large-diameter tubes, comprises a self-centring work clamp 15 and a self-opening die-head 18 which is rotated through reduction gears and has a guide member 19 with feed screw threads 21 engaged by a fixed screw 22. Work-holders.-The work clamp 15 is removably supported on four rods 14 extending from the body 11 and has a pair of transverse rods 27 on which jaws 28 are slidable against the action of springs 29 fitted between them. The jaws are operated by a hand wheel 34 on a right- and lefthand threaded shaft 33 engaging nuts 32 on levers 30 which are pivoted on links 31 and engage the jaws through rollers 35. An eccentric adjustment 37 for centring the jaws relative to the die-head is provided on the pivot for the links 31. Die-heads.-The die-head 18 is rotated by an annular gear 26 engaging a shrouded sliding gear 25a splined to the motor shaft 24 and consists of two parts, the front part 43 having four tangential guides for chaser mountings 53 and the rear part 41 being secured to the guide member 19. Guide pins 47 and a shorter pin 45 connect the two parts of the head through a plate 46 which is journalled on the forward part and has cam surfaces 52 engaging the chaser mountings. Initial adjustment of the position of the mountings in their slides is obtained by angularly adjusting the camplate 46 by adjusting a pin 49 in a slot 62; fine adjustment of the pin is obtained by a plate 50 and an eccentric 55 on the pin 45. Partial threads 63 in the chasers 40 and a worm 64 enable the chasers to be adjusted in their mountings and a plate 66 clamps them in position. The interchangeable threaded bush 21 on the guide member feeds the die-head along the tube a until it meets a stop and the front part 43 continues to rotate and move forward until the pin 45 disengages from the cam-plate 46 which is then free to be rotated by springs bearing on the pin 49, so that the chasers are opened. After the screw 22 has been disengaged, the die-head can be withdrawn by a hand wheel 56 which operates a pinion and rack. Removing burrs.-A conical cutter 60 fitted on the motor shaft 24 can be used for removing burrs from the end of the threaded tube.