Patent GB-591908-A (GB)
Title: Improvements in die sinking machines
IPC: B44B3/00
Filed: 1944-11-03
Abstract: 591,908. Engraving. FILTNESS, A. J. Nov. 3, 1944, No. 21579. [Class 100 (ii)] [Also in Group XXII] In a die-sinking machine the pattern and work are mounted on two similarly rotating tables and the tracer and cutter are carried by a frame swinging on trunnions to provide the depth of cut copying feed, the trunnions being mounted on a table which is given a slow arcuate movement about its centre point so as to traverse the tracer and cutter completely across the pattern and work. The work table 18 and pattern table 18<1> are rotatably mounted on bearings consisting of a single ball in stems 17 adjustably positioned opposite the cutter 13 and tracer 12 by means of articulated members 14 pivoted to a central pillar 2 and capable of being locked in the adjusted position. The tracer and cutter are carried by holders 51 on cross members 44 of a frame 11 supported by trunnions 9 on a table 6 which is pivoted by a ball bearing 4 on the pillar 2. The tables 18 are rotated by worms 21 driven by universally jointed or flexible shafts 31 and a belt 28 from an electric motor 26. The work and pattern may be secured to the tables 18 by side clamps, a collar band or by adhesive such as shellac. Angular motion is imparted to the table 6 about the pillar 2, to feed the tracer and cutter across the pattern and work, by means of a cord 36 attached thereto at 38 and led over pulleys 37 to a nut 35 engaging a screw 34. The nut slides along a guide 39a to prevent it from rotating and the screw 34 is driven by reduction gearing 27 from the motor 26 or alternatively a fixed nut may traverse a splined rotating screw. The nut may be split so that it can be disengaged from the screw and returned to starting position by hand after a feeding traverse and the cord 36 acts against a suspended weight 52 attached to the opposite end of the table by a cord 53 or against a spring. During this traverse the rise and fall of the tracer about the trunnions 9 is imparted to the cutter and this motion may be limited by adjustable stop screws 56 on the table 6 engaging the frame 11. The overhanging weight of the frame 11 maintains the tracer and cutter in contact with the pattern and work, but may be assisted by additional loading of the frame. To vary the scale of reproduction the distance of the work and cutter from the pillar 2 is made different from that of the pattern and tracer and to produce intaglio work from a cameo pattern the work and cutter are located on the opposite side of the trunnions 9 from the pattern and tracer. The depth of reproductions may also be varied by adjusting the cutter and tracer at different distances from the axis of the trunnions 9. In other modifications the cutter may project upwards from the frame 11 and the work be inverted, or the pattern and work may rotate in vertical planes in opposed relation. This arrangement produces work of the same hand as the pattern whereas the arrangement of Figs 1 and 2 produces work of opposite hand. For continuous operation of the machine the screw 34 may be driven by a separate motor which is reversed at the end of each oscillation of the table 11 by means of limit switches 43 and dogs 41 on the nut 35, the cutter penetrating to a greater depth at each oscillation until the full depth of the pattern has been reached or alternatively the screw 34 may be reversed mechanically. The cutter is removed from the work on the return stroke. The tracer is shaped similarly to a gramophone needle, with a' spherical point, and the cutter may be non- rotary with a V-point of D-section, or the cutter may be rotary and driven by a belt, etc. The tracer and stationary cutter are held in the holder 51, Fig. 7, by the heel 49 of a pivoted dog 47 and a screw 50. Cuttings, catching and removing.-Swarf from the cutting tool may be removed by an air blast provided by a fan, which may be driven from the shaft 31, and led to the tool by a flexible tube.