GB671372A - An improved method of shaping workpieces and apparatus for performing same - Google Patents

Abstract

671,372. Centreless grinding. MASON, A. C. Jan. 28, 1949 [Jan. 28, 1948], No. 2396/49. Class 60. [Also in Group VII] A method of shaping a work-piece comprises simultaneously rotating the work-piece and feeding it axially while progressively removing stock from a number of annular zones spaced along its length. The method is carried out in a centreless grinder in which a grinding wheel 56, Fig. 1, is provided with helical ribs 146, Fig. 3, and driven by multiple V-belts 12 from a motor 4, while the regulating wheel 54 is driven through a double chain drive from a countershaft 68 and the grinding wheel. The support 26, Fig. 6, for the regulating wheel is mounted on a bar 28 one end of which is provided with a spherical collar 34 supported in a fixed bearing 22 while the other end is supported in a block which can be adjusted along a guide way 36 towards and away from the grinding wheel by a screw 46, locking means being provided for the block. This adjustment enables the regulating wheel axis to be inclined to the grinding wheel axis in the horizontal plane. To enable a similar adjustment to be effected in the vertical plane, the regulating wheel is connected to its support 26 by a pivot 82 and a screw 88, an indicator 85 and a locking bolt 84 being provided. The throat size is determined by setting a micrometer 104 fixed to the standard supporting the grinding wheel and advancing the regulating wheel bodily towards the grinding wheel until an abutment surface on the regulating wheel mounting makes contact with the micrometer. The regulating wheel is advanced by a screw 102 which incorporates a spring to allow the regulating wheel to move and free the work if the latter should seize in the throat. The work is fed along a work-rest blade which is provided with an inverted L-shaped guide at the inlet end and a trough at the discharge end to collect the workpieces and deposit them in a container. To ensure the retention of the work in the throat, a guard is secured to the grinding wheel mounting so that it overlies the work-rest blade. Successive zones on the stock are cut progressively deeper by the ribs of the grinding wheel until, at some point such as 147, the stock is severed into separate solids of revolution which continue to be ground until they emerge from the throat. The grinding wheel or the regulating wheel may be made in the form of a hyperboloid. Regulating wheels so formed are made of rubber in order that the variation in peripheral speed along the length of the wheel will not produce an abrasive effect. The stock may be solid or tubular and of plastic or other composition.