Patent GB-503989-A (GB)
Title: Improvements in truing mechanism for grinding wheels
IPC: B24B53/08
Filed: 1938-01-11
Abstract: 503,989. Trueing grinding - wheels. JONES & LAMSON MACHINE CO. Jan. 11, 1938, No. 877. Convention date, Jan. 29, 1937. [Classes 60 and 124] Mechanism for trueing grinding wheels, intended for grinding screw-threads, comprises, for U.S.A. standard threads, a casing 51 mounted on the wheel slide of the grinding- machine and having in its forward end 60 a re-entrant portion 61 with inclined walls 62 in which are mounted, in packed bearings 66, sleeves 63 each having journalled therein a shaft 70. Each shaft has thereon an arm 71 carrying eccentrically a diamond tool 72 ; the shafts 70 are at 120‹ to each other and the tools 72 treat the side faces 75 of the grinding-wheel 1. The shafts are rocked, to carry the diamonds over the wheel, by an oscillatory cam drum 76 having therein grooves 77, one engaging a follower on each of two bars 78 secured to the respective shafts 70. The shafts 70 also may be given axial movement, to produce, with the rocking movement, the desired profile on the grinding-wheel, by means of cam plates 92 supported adjustably by screws 93, 94 in the casing wall 62 and engaged by followers 91 on the bars 78. The cam drum .76 is journalled on a vertical shaft 96 and driven by a worm 97. In order to withdraw the diamonds from the wheel faces as they move towards the periphery of the wheel, thereby preventing splintering of the wheel edge, a cam plate 101 is provided on the shaft 96 and is moved by a pin 103 on the drum 76, which pin engages shoulders 107, 108 on the plate to turn this, thereby, by means of inclined faces 110, moving arms 112 pivoted at 113 and having notches 115 to engage pins 114 on the arms 78. The peripheral edge of the wheel 1 is trued by a third diamond 130 carried by an arm 132 mounted on a shaft 131 oscillated by cam surfaces 137 on the drum 76, which engage rollers 136 on a collar 135 clamped to the shaft ; the shaft is pressed axially by a spring 140 and is adjusted by a micrometer screw 146. In a modification, the rock-shafts carrying the diamonds for treating the side faces of the wheel are oscillated by gear segments thereon, which engage racks operated by arms on a shaft oscillated by a rotating cam ; axial movement also is given to the rock-shafts by mechanism similar to that described above for that purpose. The periphery of the wheel is trued by a diamond carried by a rock-shaft oscillated by a part of the cam, and the rock-shaft also may be moved axially; in order to avoid chipping of the wheel edge, the entire mechanism is retracted during the return traverse of the side trueing devices. As applied to the trueing of a wheel for grinding buttress threads, and haying a side face hollowed out to allow of working up close to a shoulder, the side face trueing diamonds are operated similarly to the form first described above, but with the axes of the rock-shafts 'set at suitable angles, and the peripheral trueing tool is operated from a recess in the cam, whilst a fourth diamond is provided, to cut out the hollow in the wheel, operated by a sliding bar actuated by a pin on the cam. In order to use the combined rocking motion and axial motion of the side face trueing tools to produce special shapes of wheel contour, the apparatus shown in Figs. 20 and 24 is employed, the rock-shafts 320 being urged axially by springs 322 and oscillated by a cam 314, the groove 334 in which oscillates a T-shaped member 331 having slotted ends engaged by rollers 336 on arms 330 on the shafts 320. The desired axial movement of the rock-shafts 320 is produced by edge cams 340 adjustable by screws 346 on a mounting block 345 and engaged by followers 350 on arms 351 pivoted to collars on the shafts 320 and having lower arms engaging fixed abutment pins. Each tool 376 is carried by a V-shaped block 372 engaging a corresponding recess in the head 356 of the rock shaft. Specification 478,757 is referred to.