Patent GB-908247-A (GB)
Title: Improvements in or relating to centreless grinding machines
Inventor: WELBOURNE WILLIAM DUNCAN
IPC: B24B5/38
Filed: 1960-03-29
Abstract: 908,247. Grinding. KAYSER, ELLISON & CO. Ltd. June 29, 1961 [March 29, 1960], No. 10985/60. Class 60. [Also in Group XXX] Feed means, for a centreless grinding machine of the type in which feeding of workpieces through a grinding station formed by a grinding wheel and a pressure wheel is effected by inclination of the pressure wheel and adapted for finish grinding lengths of drawn wire or small diameter bar stock, comprises a peripherally grooved roller with horizontal axis adapted to be disposed transversely to the feed path of the machine in advance of the in-feed table, and with the bottom of the groove at the top side of the roller at least at the same height as the bottom of the channel of the in-feed table and aligned with that channel, a second roller disposed axially parallel to and above the grooved roller and adapted to be urged towards the grooved roller, and adjustable speed drive means for at least the bottom roller, whereby that roller is able to feed along the channel the leading end of a length of wire supplied to the nip between the two rollers and also provide assistance to feeding of the leading end of the wire into the grinding station until the pressure wheel is fully effective to maintain a constant feed rate. A peripherally grooved roller 11 is carried by a spindle disposed transversely to the feed path of a centreless grinding machine in advance of the in-feed table 13 which has a channel 14. A roller 15 above the roller 11 is urged towards the latter by springs 16 and can be raised by a solenoid 17. The roller 11 and four further peripherally grooved rollers 18 are driven, through belts 20, 21 by adjustable speed electric motors 22, each motor being capable of providing all the drive in case of failure of the other motor. The grooved surfaces of the rollers are lubricated. The spaces between the rollers may be filled by grooved wood blocks 23 providing further support for the wire lengths and which are also lubricated. A magazine for storing wire lengths and supplying them individually to the rollers 11, 18 and at the leading end direct to the channel 14 has a vertical hopper consisting of a plate 33 and guide strips 34, the latter being welded to bars 35 each adjustably secured in a horizontal guide block 37 on the upper end of a bar 38 adjustably secured in a vertical guide block 40. A lower inclined continuation 42 of the plate 33 forms a shoot leading from the bottom of the hopper to the rollers 11, 18 and an upper inclined continuation 43 of the plate 33 extends from the top of the hopper to a back plate 44. Each guide strip 34 has a continuation 45 extending above and at the same inclination as the plate 43 but terminating short of the back plate to allow wire lengths to be dropped on to the upper end of the plate 43 and to be guided thereby to the hopper. An end plate 46 projects beyond the surfaces of the plates 33, 43 to form a stop for the leading ends of wire lengths in the magazine. Delivery of individual wire lengths from the magazine is controlled by retractable supports 48 provided at intervals along the length of the magazine and co-operating with dogs 49. Each support 48 consists of a round bar which is guided in holes in brackets 53, 54, 55, is advanced by a spring 57 and retracted by a solenoid 58. A block pinned to the bar 48 carries a spindle 70. Each dog 49 has a knife-edged leading end 49A and is slidable in a block adjustably supported below a plate 60 by bolts 61. The dog 49 carries a spindle 71. The spindles 70, 71 are guided by slots 67, 68 in the plate 60 and carry rollers 72, 72 interacting with slots 73, 73 in a lever 66 pivoted to the plate 60, so that the support 48 and dog 49 move simultaneously but oppositely, whereby the dog 49 supports the wire lengths above it when the support 48 is retracted to release the lowest wire length. A beam is projected by a light source 74 through a groove 75 in the underside of one of the adjustable guide members 76 of the channel 14; a photo-electric cell is located beyond a hole 78 through the fixed guide member 79 of the channel aligned with the groove 75. When the trailing end of a wire length travelling along the bottom of the guide channel passes beyond the groove 75 and hole 78, the beam reaches the photo-electric cell which is coupled to an energizing switch for all the solenoids 58 and for the solenoid 17, so that another wire length is delivered from the magazine and the roller 15 is lifted from the roller 11. A shutter can be swung over the outer end of the groove 75 for interrupting the beam in the absence of further wire lengths from the magazine or when a test length is to be passed repeatedly through the grinding machine for setting-up. An adjustable delay relay is preferably provided in the energizing circuit for the solenoids so that release of a wire length from the magazine takes place at a predetermined time after the trailing end of a preceding length has passed beyond the groove- 75 and hole 78, thereby preventing the leading end of a wire length from overlapping the trailing end of a preceding wire length in consequence of the difference between the feed rate of the grinding machine and the feed rate of the rollers 11, 18. A stop plate 81 having a projection 82 extending into the channel 14 is provided between the photo-electric unit and the grinding machine so that only one wire length may pass below the projection at any time. Specification 894,155 is referred to.