Patent GB-587683-A (GB)
Title: Improvements in or relating to grinding or abrading apparatus
IPC: B24B53/04
Filed: 1944-07-11
Abstract: 587,683. Trueing grinding-wheels. SHEFFIELD CORPORATION. July 11, 1944, No. 13246. Convention date, June 21, 1943. [Class 60] A trueing device for a grinding-wheel for screw threads &c., comprises a grinding-wheel support having a passage transverse to the grinding-wheel axis in which passage is a carrier for the trueing means and having a rotatable portion movable axially, and a second portion arranged for axial movement only and supported by antifriction means on a standard ; the trueing means comprises two diamonds which are moved towards the wheel axis and simultaneously separated axially of the wheel. The grinding-wheel 11, Figs. 2 and 3, is mounted on a part 12 of a barrel 13, which is rotatably adjustable by hand-operated worm gearing 16, 17 in a slide 14, and in the barrel is slidably mounted a carrier 24 supporting the trueing diamonds 25, 26 on holders 27, 28 and an operating motor 29. The carrier is of cylindrical form with an end wall 31 secured bv arcuate slots and bolts to the carrier so as to be adjustable in accordance with the thread angle of the work ; the entire carrier is movable to and from the grinding-wheel and the holders 27, 28 are supported for transverse movement on guide bars 35, 35' which are also movable to and from the grinding-wheel. The rear end of the carrier is supported by rollers 42 mounted in the wall 31 and running on racks 41 on a standard 37 fixed to the slide 14. The standard 37 carries, by means of pivoted screws 44, an abutment bar 43 rotatably carrying a threaded shaft 49, held against endways movement and rotation by a clamp plate 50, and engaging a nut 52 carried by the wall 31 and rotatable by ratchet gearing 53 controlled by a solenoid ; part rotation of the nut at the start of a trueing cycle feeds the carrier by the amount to be removed from the grinding-wheel, and, when a new wheel necessitates re-setting of the device, the plate 50 is loosened and the shaft 49 rotated. Springs 58 in telescoping tubes 59, 60 act between the bar 43 and the wall 31 to eliminate lost motion. The motor 29 drives, through a gear train 61 ... 67, a toothed wheel 68 forming the driving element of a one revolution clutch including a driven plate 69 secured to a shaft 70 and carrying a drive arm 72 which has a part 74 engageable with the teeth of the wheel 68 by a spring 75 ; a finger 76 on the arm, by engagement with a stop 77, moves the arm out of engagement with the wheel 68, the stop being operable by a solenoid at the beginning of a trueing cycle to. free the arm. The shaft 70 also carries a double cam slide plate 81 guided by slots on a stud 83 and shaft 70, the plate 81 having also a slot 85 engaging a lever 86 pivoted on a shaft 87 and having an arm 88 connected at 89 to a bellcrank lever 90, 91 pivoted on a pin 92 on a mount 94. The mount 94 is connected by a bellows 93 to the carrier 24 and has an opening for the supports 27, 28 ; rods 95, 953 in the mount are slidable in guide holes on parts 96, 96<1> of the carrier, springs 48 urging the mount to a retracted position. The mount is moved to and from the grinding-wheel by movement of the plate 81, the lever arms 88, 90 forming a toggle ; the forward movement produces the forward component of movement of the diamonds. The horizontal component of movement is obtained by sliding the diamond holders to and from each other, the holders being slidably supported by the bars 35, 35<1> and, at their rear ends, by a bar 99 fixed to the mount 94, toggle linkages 91, 97 serving'to produce the movements. The movements of the diamonds are shown diagrammatically in Fig. 10, where a, a3 are the initial portions and b, b<1> the points reached by feed of the carrier by operation of the ratchet gear 53; the diamonds then move to c, c<1> by an eccentric movement of the shaft 87, before the arm 86 is moved, produced by a slotted arm 100 controlled by a bell-crank lever 101 pivoted at 102 and having a pin 103 engaging a slot in the arm 100. The movement of the arm 100 advances the pivot of the lever 86. From the points c, c' the diamonds move along the paths c, d, c<1>, m, the movement being produced by the toggle linkages.