Patent GB-1047807-A (GB)
Title: An improvement in or relating to grinding machines
Inventor: PALMER RAYMOND LESLIE
IPC: B24B49/18
Filed: 1964-07-04
Abstract: 1,047,807. Grinding. CHURCHILL GEAR MACHINES Ltd. Sept. 27, 1965 [July 4, 1964; July 7, 1964], Nos. 27685/64 and 27887/64. Heading B3D. A grinding machine comprises, grinding- wheel 11A mounted on a grinding head 10 which is movable towards and away from the axis of a workpiece to be ground, a trimming device (not shown) for the grinding-wheel, means for effecting relative traversing movement of the workpiece and grinding-wheel, infeed mechanism for providing incremental approach between the grinding head and workpiece, mechanism actuable by the infeed mechanism at predetermined. intervals to terminate traversing and infeed, disengage the grinding-wheel from the workpiece and render the trimming device effective on the grinding. wheel, and a compensating device which is effective after disengagement of the grinding- wheel from the workpiece to displace the grinding head in relation to the infeed mechanism towards the axis of the workpiece. The machine is for automatically grinding splines on a workpiece which is held between headstock and tailstock on a work-table slidable on guides on a bed by means of a double-acting hydraulic piston and cylinder. The workpiece is clamped by mechanism described in Specification 1,045,638 to an indexing mechanism and a trimming device, such as described in Specification 1,047,806 is mounted at the end of the work-table remote from the headstock. The grinding head 10 is mounted for movement on vertical ways on a column extending upwardly from the bed and has a motor-driven spindle 11 carrying the grinding-wheel 11A and a non- rotatable nut 12 engaged by a spindle 13 secured to a sleeve 14, in turn, secured to a gear 15. The latter engages a gear 16 meshing with a gear 17 secured to a clutch shaft 18 having a splined part engaged with a clutch part 19. The part can either be engaged with a wheel 21 engaging a worm 27 on a shaft 28, in which case rotation of the shaft effects rotation of the spindle 13 to adjust the vertical position of the grinding head, or be engaged with a ratchet-wheel 20 rotatable in steps by a pawl 22 on a lever 23 which is pivoted about the shaft 18 and has a swivel pad 25 engaged in a transverse slot in a rod 26 movable by an hydraulic jack, the latter being operated during trimming to move the grinding head to compensate for the trimming operation. The upper end of the spindle 13 is rotatably received in a double thrust bearing 30 on a carriage 29 vertically slidable on guides on the column and has a sine bar 31 engaged between rollers 33 on a slide 32 movable along horizontal guideways by an hydraulic jack 34. The slide 32 has a further roller 36 engaging a stepped cam 35 on a slide 37 vertically movable by an hydraulic jack 38 actuated step-by-step under the control of a limit switch 39 co-operating with notches 40 in the slide. A further limit switch 44 actuated by pegs 43 selectively engaging holes 42 in the slide initiates the trimming device. In operation, a stop 41 is adjusted to determine the final position of the slide 32 and the finish size of the workpiece, the clutch 19 is engaged with the wheel 21 so that the shaft 28 can be rotated by a hand wheel to bring the grinding-wheel into contact with the workpiece, the clutch then being engaged with the ratchet-wheel, and a stop for the rod 26 is adjusted to determine the amount of movement of the ratchet-wheel 20 necessary to compensate for the trimming operation. At the start of grinding, the roller 36 engages the lowest step on the cam 35. If the workpiece is to have six splines, the workpiece is traversed six times past the grinding- wheel and is indexed a sixth of a rotation after each pass. A disc on the indexing mechanism then operates jack 38 to move the slide down one step so that the roller 36 engages the next step to move the slide 32 to the right and the slide 29 and head 10 downwardly, the jack 38 being controlled by the limit switch 39 engaging the next notch. The above procedure continues until the last step on the cam is reached, which step is wider than the others so that when the slide 37 is next moved by the jack 38, a limit switch is operated to cause the jack 34 to move slide 32 to a finish position abutting stop 41. Trimming can be effected when desired by selective engagement of the pegs 43 in the holes 42. When a peg 43 actuates the limit switch 44, the work-table is moved to position the grinding-wheel clear of the workpiece and adjacent the trimming device, and the jack 34 is actuated to move the slide 32 into abutment with the stop 41. The jack then moves rod 26 and the ratchet 20 to move the head 10 an amount to compensate for the material removed during trimming. After trimming, the jack 34 is actuated to urge the roller 36 back into engagement with the cam 35.