Patent GB-646395-A (GB)
Title: Improvements in or relating to grinding machines
IPC: B24B49/18
Filed: 1947-12-22
Abstract: 646,395. Grinding machines. GOOD, I. E., and KEIGHLEY GRINDERS (MACHINE TOOLS), Ltd. Dec. 22, 1947, No. 33860. [Class 60] In a grinding machine the movable member of the feed-screw and nut mechanism for advancing and retracting the grinding wheel is driven by one element of an epicyclic gear whereby another element is connected to the trueing control and the third element to the grinding control so as to be operated thereby, the element connected to the trueing control acting as the reaction element of the gear for grinding-wheel feed movements and the element connected to the grinding control as the reaction element for trueing movements. The rotating work 14 is mounted on a work-table 13 movable on longitudinal ways 11, 12 on the machine base 10. The grinding wheel 26 and its driving motor 16 are mounted on a cross slide 15 to which is secured a non-rotatable feed screw 22 engaging a nut-sleeve 21 mounted by thrust bearings 24, 25 in the hollow rod 20 of a piston 19 working in a cylinder 18, the piston being hydraulically actuated to effect approach and withdrawal movements of the grinding wheel relative to the work. Feed of the grinding wheel is effected by rotating the nut-sleeve 21 which has a gear 23 meshing with a long gear 30 on a shaft 31 ; backlash in the screw-and-nut mechanism is taken up by a weight 29 on a chain 27 connected to the screw 22. The shaft 31 carries a gear 34 meshing with a gear 35 integral with a sun gear 27, the double gear 35, 37 being freely rotatable on a shaft 36 to which is keyed a second sun gear 38. Planet gears 44, 45 having different numbers of teeth and meshing with the sun gears 37, 38 respectively, are carried by a stub shaft 43 on a disc 42 on a shaft 39 provided with a handwheel 54. The shaft 36, carrying the second sun gear 38, carries a gear 46 meshing with a gear 47 on a shaft 48 carrying a worm wheel 49 meshing with a worm 50 on a vertical spindle 51 having a knob 53. By this arrangement, operation of the hand-wheel 54 serves to put on cut, and operation of the knob 53 moves the grinding wheel for trueing without affecting the setting of the hand-wheel 54. The hand-wheel 54 carries a ring 55, adjustably secured thereto by hand nut 56 and teebolt 57, co-operating with an index mark on a bead 59 on the cover 58. A powerfeed ring 60 is carried by the ring 55, being adjustably secured thereto by hand nut 61 and locking bolt 62. The ring 60 carries a feed gear 63 meshing with a gear 64 on an idler stub shaft 65, gear 64 being secured to a gear 66 meshing with a rack 67 formed on the piston rod 68 of a power-feed cylinder, operated hydraulically under the control of a valve actuated by dogs on the work table 13 so as automatically to put on cut at each end of the stroke of the work table 13. The ring 55 carries a dead-stop 70 co-operating with a stop-pawl 73 to stop the feed when the work is to size ; the stop-pawl 73 is mounted, on a stud 72 and has a handle whereby it can be moved into inoperative position. A trueing diamond 75 is carried by a slide 76 adjustable, by knob 77, on a bracket 78 secured to a tail-stock on the work-table 13. For trueing, the work-table stroke is extended to carrying the diamond past the grinding wheel, which has been retracted from the work by piston 19 ; the diamond is adjusted so that its position corresponds precisely with that which will true the grinding wheel to the desired size for finishing the work to the required size when the dead stop 70 on the ring 55 has been fed up to the stop-pawl 73. Specification 360,557 is referred to.