Patent GB-264786-A (GB)
Title: Improvements in and relating to grinding or abrading machines
IPC: B24B47/20
Filed: 1926-06-24
Abstract: 264,786. Heald Machine Co., (Assignees of Taylor, E. M.). Jan. 25, 1926, [Convention date]. Round holes, enlarging and trueing; trueing rotating tools.-In a grinding- machine in which a grinding-wheel is reciprocated relatively to a rotating work-piece and automatic cross feeding means are provided, and in which also means are provided for trueing the grinding-wheel prior to the finishing cuts, and after completion of grinding the wheel is withdrawn from the work, the trueing operation and the withdrawal of the wheel are controlled by the movement of the cross-feeding mechanism, in which also is embodied means for advancing the grinding-wheel an amount to compensate for wear and trueing. The machine, shown as an internal grinding- machine, consists of a bed on which is a reciprocating table 1 carrying the grinding-wheel 5 on a cross slide 2<a>, the work being carried in a head 3; the trueing-diamond 9 is supported at the rear of the machine. The slide 2<a> is moved by a screw 10, clockwise rotation of which advances the slide to feed the wheel 5, and the screw may be rotated manually by a hand wheel 11 carried by a piece 11<a> rotatable on a sleeve 16 keyed to the screw. The piece 11<a> carries a stud 13 on which are integral pinions 14, 15 of slightly different sizes, the pinion 14 gearing with teeth 16a on a sleeve 16 and the pinion 15 gearing with teeth 17<a> on a sleeve 17 in which the screw 10 is rotatable. Secured to the piece 11<a> is a ratchet wheel 12 which is actuated on each working stroke by a pawl 38, Fig. 6, to give the automatic feed. Adjustably secured to the piece 11<a> is a ring 18 having scale markings thereon cooperating with a fixed pointer 73, and on the ring also is a cam 20 which actuates levers 23 to close electric contacts 25, 26; when the first pair of contacts are closed, the table 1 is moved in an amplified stroke and the wheel is trued by the diamond 9, after which the normal working stroke is resumed until the cam 20 closes the second set of contacts when, the work being to sixe, the wheel is withdrawn from the work to a remote position to allow of removal and replacement of the work. In order to produce the automatic feed, the machine carries a stationary bar 32 on which is an adjustable cam 33 which engages a roller 34 on a member 35 pivoted at 36, a lug 37 normally holding the parts in inoperative position. The pawl 38 is pivoted on the member 35, a spring plunger 39 tending to press the pawl against the ratchet, the pawl normally, however, being held out of contact with the ratchet by pin 43, carried by an adjustable lever 44. The mechanism for compensating for wear of tho wheel comprises an arm 48 attached to the table 1 and carrying a shaft 51 on one end of which is a downwardly extending lever 52, Fig. 7, connected to the shaft by a pin 54 and a slot in the lever, whereby when the table moves outwards after completion of grinding, the lever by contact with a lug 53 on the bar 32 rotates the shaft 51, but on the return of the table does not rotate the shaft. On the other end of the shaft 51 is a member 56 to which is pivoted a pawl 59 adapted to engage a ratchet wheel 62 keyed to the sleeve 17, and frictionally engaged with the ratchet 12 by a wire 68, lying in a circumferential groove 67 in the ratchet 12. When the pawl 59 feeds the ratchet 62, the whole feed mechanism and the screw 10 are rotated bodily owing to the friction of the parts, and the slide 2a is fed the necessary amount to compensate for wear of the wheels 5. The amount of the feed is adjustable by a shield 70 for the ratchet 62. The parts are normally held locked by a member 64 having teeth 65 engaging the ratchet 62, the member 64 being held in that position by a spring 57 acting on the member 56, a plate 66 on the member engaging the member 64; when the member 56 is moved by the arm 52, the plate 66 releases the member 64. Specification 256,582 is referred to.