Patent GB-456595-A (GB)
Title: Improvements in or relating to grinding and polishing machines
IPC: B24B21/02
Filed: 1935-07-13
Abstract: 456,595. Grinding and polishing wire. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.-(Crucible Steel Co. of America; 42nd Avenue, New York, U.S.A.) July 13, 1935, No. 20045. [Class 60] Wire stock S drawn from a spool B is ground and polished by passage through a rotating hollow shaft 3 carrying a head or heads 5, each supporting a motor-driven abrasive wheel 24 and a work holder 50 maintaining the stock in contact with the abrasive wheel. The shaft 3 is journalled in a standard 1, lateral movement being prevented by flanges 6 on the shaft engaging corresponding recesses in the bearing member 4. The standard 1 also carries an electric motor 46 rotating the shaft 3 by chain-gearing 48. Variable speed electric motors 9 carrying the abrasive wheels, 24 are mounted in octagonal openings 8 in the heads 5 and can be adjusted radially, to compensate for wear of the abrasive wheels by means of screw studs 26. The weight of the motors and abrasive wheels is counterbalanced by adjustable weights 36 mounted in recesses 34 in the heads 5. Each work holder 50 comprises a bracket 51 which is secured to the head 5 and carries a fixed holding plate 53 and an adjustable pressure plate 63 in contact with the stock S. The pressure plate 63 has an inclined upper surface maintained in contact with a similarly inclined surface on a guide member 58 secured to the bracket 51 by a spring-pressed retaining plate 72 acting on screws 70 which project from the pressure plate through a slot 71 in the guide member 58. The plate 63 may be adjusted along the guide member 58 by means of a nut 77 carried by a pivoted arm 78 on a bracket 80 carried by the standard 1, the nut 77 moving axially a screw 76 engaging a circular plate 67 at the outer end of the plate 63. The plate 67 has a central aperture 68 through which the stock passes. The stock S is wound, after being ground, on a drum 87 rotated by an electric motor 89, tension in the stock being maintained by a block 85 arranged in alignment with the passage 23 through the shaft 3. Current is supplied to the motors 9 by means of brushes 42 engaging collector rings 44 on the hubs of the heads 5. Casings 97 carried by shelves 2 on the standard 1 surround the abrasive wheels and enclose water or other cooling means for the stock, the liquid and particles being withdrawn through conduits 98. Fig. 12 shows a modified form of work holder comprising a slide 108 slidable radially in guides on the head 5 and carrying a pressure bar 111 engaging the stock S. When the head 5 rotates the slide 108 tends to move radially inwards owing to the rotation of a cam 114 by an arm 121 carrying a weight which flies outwards by centrifugal force. In a modified machine construction shown in Fig. 17, the abrasive wheels are replaced by abrasive belts moving in opposite directions, the work holder being dispensed with. Each head 133 carries two electric motors 138 driving pulleys 140 supporting abrasive belts 145 which are maintained in tension by adjustable pulleys 148, the belts and pulleys on one head being arranged substantially at right angles to those on the other head. The heads are rotated by a separate electric motor 131 through belt gearing 134. The surface speed of the abrasive belts 145 may be adjusted without changing the speed of the heads 133 by varying the frequency of the current supplied to the motors 138.