Patent GB-1158431-A (GB)
Title: Improvements in Multi-Spindle Die Lapping and Polishing Machines and to a method of operating the same
Inventor: TARRY FRANK HAROLD
IPC: B24B5/48
Filed: 1966-02-19
Abstract: 1,158,431. Lapping; polishing. RUDKIN & RILEY Ltd. 16 Feb., 1967 [19 Feb., 1966], No. 7387/66. Heading B3D. A high speed multi-spindle machine for lapping and polishing dies of tungsten carbide or other hardmetal for drawing wire, rods &c. is of the kind comprising: (i) an upright framework including a base section; (ii) two spaced vertical columns mounted in the base section for vertical reciprocation by an eccentric shaft; (iii) a horizontal head secured to and extending between the columns; (iv) a plurality of vertically disposed needle or lap holders detachably mounted in the head and incorporating rotary driving spindles; (v) driven pulley means at the top of the framework from which the spindles are driven; and (vi) below and in alignment with the respective needle or lap holders, a set of die pans for holding dies to be lapped or polished; and is characterized by comprising means adapted to drive the needle or lap spindles in one direction at a high rotational speed suitable for die lapping or polishing, and to drive the die pans in the opposite direction at a relatively low rotational speed. A horizontal head 4 is secured to and extends between spaced vertical coumns 3 mounted for vertical reciprocation in the base section 2 of an upright framework 1. The base section 2 contains an oil sump 5 and has a cover-plate 5a with an interposed block 6. A drive shaft 22 mounted in bearings 23 and working in the oil sump 5 has eccentric portions 24 connected by links 25 to the lower ends of the columns 3; the upper ends of the columns have extensions 26 passing through bores in the head 4 and located at their upper ends in housings 27 fixed to the top of the framework 1; springs 28 in the housings bias the columns 3 downwardly. The shaft 22 is driven, through a belt 20, by an electric motor (15). The head 4 makes 600 reciprocations per minute. Lap holders 7 removably mounted in recesses in the head 4 are driven by spindles 8 rotated by pulleys 9 disposed at the top of the framework 1, the holders having spring-biased chucks 7a receiving laps 12. The motor (15) drives, through steel bevel gear (46) and nylon bevel year (47), a vertical shaft (48) carrying a pulley (50) driving a belt 51 which contacts the pulleys 9; idler rolls 53 maintain the belt in firm engagement with the pulleys. The holders 7 rotate at 2500 r.p.m. Mounted for vertical sliding movement centrally through each pulley 9 is an element 54 having at its lower end a circular plate 55 biased away from the framework by a spring 56 and having on its underside a dog 57 with a diametral recess into which fits a diametral tongue 58 on the driving spindle 8. To disengage the drive, the plate 55 is raised against the influence of the spring by operating a lever 59 pivotally mounted on the head 4 and acting through a lever 63 and a clutchoperating plate 66. Die pans 10 for the die holders 11 are mounted in tubular housings 13 extending vertically upwards from the cover-plate 5a and connected by webs 14. Secured to the underside of each die pan is a sleeve 34 slidably keyed on a shaft 35 and lubricated from a tube (38) fed by a drip-feed reservoir (39). The shaft 35 has a gear-wheel 36 meshing with a worm 33 on a shaft 32 driven, through gears 29, (30), 31, from the shaft 22 which may carry a flywheel. The die pans 10 rotate at 11 r.p.m. Mounted on the base 2 adjacent each die pan is a screwthreaded spindle 40 having a knurled nut 41 supporting a sleeve 42 having an arm 44 provided with a pad 45 of wear-resistant material abutting the underside of the die pan, whereby rotation of the nut 41 vertically adjusts the die pan. The sleeve can be moved to inoperative position by a lever 43. The die holder 11, Fig. 4, has radial pins 68 received in inverted-T slots 69 in the die pan 10. The die is held in the holder by a screw 70; the holder has a cap 71 fitting on top of the die for retaining abrasive around the working end of the lap. The cap has a central cylindrical portion 72 with a hole 73 for reception of the lap and a surface 74 converging downwardly towards the hole.