Patent GB-778164-A (GB)
Title: Improvements in or relating to diamond truing devices
Inventor: DEAKIN THOMAS MEYRICK
IPC: B24B53/075
Filed: 1954-06-21
Abstract: 778,164. Trueing grinding wheels. DEAKIN GEARS, Ltd. June 17, 1955 [June 21, 1954; April 19, 1955], Nos. 18151/54 and 11269/55. Class 60 The working tip of a diamond or like tool for trueing a grinding wheel is located during the trueing stroke by keeping another tool in contact with the locating surface of a fixed register member disposed adjacent the wheel and causing this - locating tool to traverse a trued zone of the wheel between successive locating functions so that automatic compensation is provided for wear of the trueing tool. For trueing the plane face 2, Figs. 1 and 2, of a grinding wheel, 1, an oscillatory carrier 5 carries two projecting diamond tools 4a, 4b and two machinable locating tools or pegs 9a, 9b which are initially set flush with or slightly proud of the tools; the carrier is urged towards the grinding wheel and the pegs 9a, 9b bear against a rigid segmental register plate 10 disposed adjacent the periphery of the grinding wheel with its locating surface fixed in a datum plane 3 in which the trued face of the grinding wheel is always arranged to be set. With the wheel in trueing position so that its face is slightly proud of the plane 3, the carrier 5 is rotated to cause one of the tools, say 4b, to make a' trueing traverse over the. face 2 while the corresponding peg 9b locates it by engaging the register plate 10; as the tool 4b traverses the wheel the other peg 9a follows it and is ground back by the trued face of the wheel so that it is correctly set for the next trueing stroke. The'carrier 5 may then be either rotated further in the same direction to its initial position or reversed to bring the other tool into trueing operation. The carrier 5, Fig. 4, which consists of two parts 57, 58 keyed on a shaft 11, is mounted for rotation in a bracket 12 movable on bearings 13, Fig. 5, on an arm 16 which also carries register plate 10. This arm is so controlled by a subsidiary slide 22 on the grinding wheel retracting slide 101 that, as the grinding wheel 1 is moved further into the work W to compensate for wear, the position of the axis 6 of the carrier 5 is correspondingly adjusted in the 'direction XY; for this purpose, the slide 22 as it advances to compensate for wear acts through a roller 20 to advance the arm 16 in the direction XX. Oscillation of the carrier is effected by a cable acting against a spiral spring 51, the limits of rocking of the carrier being set by stops. Springs act on the bracket 12 to urge the locating pegs against the register plate. In the arrangement shown in Figs. 11 and 12, a single tool 4 is clamped in a rotatable carrier 5 and two locating pegs 9a, 9b are carried on a block 5a which is mounted rotatably in the carrier 5 and spring-urged to a central position in which both pegs engage a register plate 10. As the carrier 5 is oscillated for the trueing strokes, an abutment 71- on which the tool 4 is mounted alternately engages the ends of a lug 70 on the block 5a and so causes the pegs 9a, 9b alternately to follow the tool over the trued surface; while one peg is passing over the trued surface the other is contacting the register plate. The carrier 5 may be moved at a greater speed over its idle arc prior to its action on the carrier 5a than during the actual trueing stroke For trueing the conical face 2<SP>1</SP>, Fig. 13, of a grinding wheel 1, the tool carrier 5 is mounted on a cross slide 73 which is biased by a spring 74 in the direction of the register plate 10a on a main slide 72 arranged to be reciprocated in the direction of the arrows 30. The locating pegs 9a, 9b are mounted on a block 5a which is journalled in the carrier 5 by a shaft 75 rotatable by a gear 76 from a reciprocating rack 77. The wheel is trued-by reciprocating the tool 4 over the face 2<SP>1</SP> and during each trueing stroke one only of the pegs 9a, 9b contacts the register plate while the other peg follows the tool across the trued face; between successive to-and-fro strokes the block 5a (with the carrier 5), is retracted from the register plate to disengage the operative peg, indexed through 180 degrees, and then advanced to position the other peg against the register plate. Since the pegs 9a, 9b will be machined concave by the wheel 1, the register plate may be convex towards the pegs. The cylindrical face 2<SP>11</SP>, Fig. 14, of a grinding wheel is trued by two tools 4a, 4b which together with two locating pegs 9a, 9b are carried by an indexable carrier arranged to be linearly traversed across the face 2<SP>11</SP> for the trueing stroke. During one such stroke, a tool 4a and peg 9b are traversed across the face 2" while the locating peg 9a engages a register plate 10a; the carrier is then indexed through 180 degrees for the next stroke in which the tool 4b and peg 9a 'traverse the face 2" and the peg 9b engages the register plate. The cylindrical face 2" of the grinding wheel shown in Fig. 15 is trued by two tools 4a, 4b mounted on a carrier 5 which is biased to hold the pegs 9a, 9b in contact with the register plates 10a 10b and mounted on slides 72. 73 controlling, respectively, the trueing traverse and infeed of the tools; the locating faces of the register plates may be flat or convex towards the pegs. If desired, the tools 4a, 4b may themselves act as locating pegs, in which case the register plate 10 is made of tungsten carbide, nitrided steel or very hard material and arranged so that each tool alternately trues the wheel and locates the other; for this purpose, the carrier 5 is indexable so as to interchange the two tools between successive trueing strokes. Alternatively, one of these tools may be replaced by a machinable locating peg, and the carrier is required to make first a wheel trueing traverse with the locating peg setting the position of the tool and then a machining traverse with the peg located by the tool. If desired, one of the tools 4a, 4b may be initially set slightly proud of the other, in which case only the trueing strokes of the proud tool will be effective until it has been worn down flush with the other. The first Provisional Specification also describes a modification of the arrangement shown in Fig. 15 wherein both the diamond tools and locating pegs are colinear and co-operate with register plates which have central longitudinal grooves to provide clearance for the diamond tools. Specification 718,101 is referred to.