GB1096223A - Apparatus for trimming grinding wheels - Google Patents

Abstract

1,096,223. Trueing grinding wheels. NATIONAL BROACH & MACHINE CO. Feb. 16, 1965 [April 14, 1964; Aug. 17, 1964], No. 6622/65. Heading B3D. A grinding wheel for use in form grinding a helicoidal surface of a workpiece is trimmed by rotating the wheel on its axis, and moving wheel forming means in contact with the wheel to trace a helicoidal surface thereon substantially identical with the helicoidal surface desired on the workpiece. The grinding wheel W is carried by a slide 18, Fig. 1, vertically adjustable on a column 16 which is adjustable about a vertical axis passing through the centre of the grinding wheel to adjust the plane of the grinding wheel to the helical angle of the workpiece. A workpiece to be ground is mounted on an arbor 24 between a headstock 22 and tailstock 26 on a table 12 reciprocatable on a bed 10, the arbor being rotated during movement of the table by a lead bar 28 which is connected to the arbor and engages a fixed nut 30. When the wheel is to be trimmed, the workpiece is moved from the vicinity of the wheel and replaced by a trimming device 34, Fig. 3, consisting of a base 56, which is mounted on a way 58 on the table 12. A block 62 is mounted on the base and has a pair of ears 64 between which a member 66 is adjustably secured. The member 66 is connected by parallel links 70 to a body 68 slidably receiving a member 76 at one end provided with a trimming tool 82, such as a diamond, and at the other end having a follower 84 which is urged by a spring 80 into engagement with the surface 50 of a template 49 carried by a plate 42 adjustably secured to a carrier 48 mounted on a bracket 32 on the bed 10 of the machine. The surface 50 is a three-dimensional involute or arcuate helicoidal surface substantially identical to that to be formed on the workpiece and, in operation, as the table is traversed to move the trimming mechanism slowly past the grinding wheel and template, the body 68 is oscillated by a handle on one of the pivots 72h or a motor engaged therewith to cause the diamond 82 to traverse a plurality of closely-spaced substantially parallel paths and trace a surface on the grinding wheel substantially identical to that 50 on the template. The template may have a surface several times larger than that to be formed on the grinding wheel and workpiece and the trimming device incorporate a pantograph mechanism. The arrangement prevents an incorrect surface being ground on the workpiece by heel and toe interference of the grinding wheel with the workpiece.