Patent GB-528225-A (GB)
Title: Grinding wheel truing apparatus
IPC: B24B53/08
Filed: 1939-05-01
Abstract: 528,225. Trueing grinding-wheels. NORTON CO. May 1, 1939, No. 12987. Convention date, May 4, 1938. [Class 60] Trueing-apparatus comprising a tool which is reciprocable into position for operating on successive grinding-wheels of different diameters, is provided with a rotary cam-device for quickly transferring the tool from one wheel to another of different diameter. The apparatus may include pawl-and-ratchet mechanism, preferably fluid-operated, for feeding the tool, and fluid-operated mechanism for reciprocating the tool. The trueing-apparatus shown in Figs. 1 and 2 is mounted on a grinding-machine comprising a slide 10 supporting grinding- wheels 12, 13 of different diameters and a motor 14. A frame 18 on the slide supports a member 19 which is mounted on a pivot 20 and engages an adjusting-screw 21 and clamping- screws 25. A horizontally-movable slide 31, mounted on the member 19, is provided with a standard 35 supporting vertically-movable slides 37, 41, the slide 37 being provided with an adjustable holder 45 for a trueing-tool 50. The slide 37 is adjustable relatively to the slide 41 by means of a screw 53 which engages a nut on the slide 37 and is rotatable in a lug 52 on the slide 41, the lower end of the screw being splined to a gear 55, Fig. 5, co-operating with a gear 56 on a shaft 57 provided with a handwheel 59. The slide 31 is traversed by means of a piston 61, Fig. 5, working in a cylinder 60 on the member 19 and connected to a valve 67 comprising a stem provided with pistons 76...79 When the valve is in the position shown, fluid passes through pipes 66, 81 and the piston and slide move towards the right, exhaust taking place through pipes 84, 86. When the valve is moved towards the right, fluid passes through pipes 66a, 84 and the piston and slide are moved towards the left, exhaust taking place through pipes 81, 86. A hand-lever 132 for controlling the valve is pivoted to a bracket 131 on a rock-shaft 109 mounted on the member 19 and having lost-motion engagement 118, 119 with an arm 112 connected to the valve-stem 75. An extension 108 of the hand-lever co-operates with adjustable stops 105, 106 on the slide 31. When the operator swings the hand-lever to the left, the valve-stem is moved to the right, and the slide 31 is moved to the left. The extension 108 is depressed and permitted to rise by a bevel on the stop 105 and then lies in the path of both the stops 105, 106. Thereafter the slide 31 and tool 50 continue to reciprocate until the operator raises the hand-lever. The shaft 109 is provided with a throw-over device comprising an arm 127 having a V-pointed spring-plunger 128 co-operating with a roller 125. The speed of the slide 31 is controlled by a valve 90 mounted on the member 19 and comprising pistons 91, 92 on a stem 97 cooperating with a cam 98 on the slide 31. When the stem rides on high parts of the cam, fluid exhausts freely through a port 94 and pipe 95, and the slide travels at high speed. When, however, the stem rides on low parts of the cam, the port 94 is closed, fluid exhausts through a needle-valve 99, and the slide travels at slow speed. The cam is so arranged that the tool 50 travels slowly across the grinding-wheels and rapidly during the other parts of the traverse. For vertically adjusting the tool into positions for co-operating with grinding-wheels of different diameters, a cam 150 mounted on the slide 31 co-operates with a roller 154 on the slide 41 which, as described above, is connected to the slide 37 carrying the tool. The cam is operated at a relatively high speed by a stationary rack 155 gearing with a pinion 156 connected to the cam. The cam is formed with concentric parts for holding the tool against vertical movement when it engages either grinding-wheel, and is formed also with parts for raising and dropping the tool from one grinding-wheel to the other. The tool is automatically fed downwards by means of ratchet-mechanism which drives the shaft 57 and is operated by fluid-pressure. The mechanism comprises a sector 163 mounted on the shaft 57 and provided with an arm 175 carrying stepped pawls 177, 178 which co-operate with a ratchet-wheel 179 secured to the hand-wheel 59. The sector engages a rack 164 on a piston 166 mounted in a cylinder 172 which is connected by a pipe 171 to the valve 67. When the valve-stem 75 is moved into either the right or left position, ports 206 coincide with a port 207, fluid passes through pipes 66a, 171, the piston is moved into contact with an adjustable stop 184, the pawls actuate the ratchet-wheel, and the screw 53 feeds downwards the slide 37 and tool 50. The piston is returned by a spring 168, exhaust fluid passing through the pipe 171, ports 208...210 and a pipe 211. Feed is regulated by means of an adjustable stop 187 for the arm 175. The stop is mounted in an arcuate guide 185 and is pivotally connected to a casing 190 supporting a worm which co-operates with teeth on the guide. A knob 192 for rotating the worm is provided with a scale and a spring- detent. The casing can be lifted to allow quick adjustment of the stop 187. The pawls can be raised by a finger-piece 181 and are held in operative or raised position by cooperation of a spring-pin with notches in the pivot of the pawls.