GB1461513A - Grinding machine for machining workpieces of non-circular cross-sections - Google Patents

Abstract

1461513 Grinding NEHEZIPARI MUSZAKI EGYETEM 8 April 1974 [24 April 1973] 15474/74 Heading B3D A machine for grinding workpieces of non- circular cross-sections comprises a powerdriven grinding disc mounted on a bed, two headstocks having synchronously driven and axially aligned spindles 27, 28 having at their free ends centres 25, 26 for holding a workpiece 1 with adjustable eccentricity, the workpiece being arranged to be set in rotation by an entrainment device 29 and the ratio between the r.p.m. of the device 29 and the spindles depends on the number of sides of the crosssectional profile to be ground, the difference between the actual and the desired ground profiles caused by the different diameters of grinding discs being equalized by a correction device 35 built into the drive of the entrainment device or in the spindle coupled thereto. The device 35, in use, causes a periodic displacement between the planatery movement of the workpiece axis and the rotational movement of the workpiece, the number of periods per workpiece rotation being twice as great as the number of profile angles or sides. The workpiece 1, Fig. 1 is mounted between the centres 25, 26 of adjustable eccentricity on the spindles 27, 28, respectively, the spindles being driven at equal rotation by gearing 30, . . . 33 from a shaft 34 driven by a belt drive 38, 39 from a D.C. motor 40. The workpiece is rotated on the centres 25, 26 by the device 29 also driven by gearing 36, 37 from the shaft 34. To compensate for the fact that the grinding wheel does not have a line contact with the workpiece and that the contact between the wheel and workpiece moves transversely from the line joining the axes of the wheel and workpiece during rotation of the workpiece, correcting device 35 is inserted between shaft 34 and the gear 36 to periodically vary the ratio of the angular velocities of the rotation of the workpiece and the rotation of the spindles 27, 28. The correcting device may consist of an eccentric 47, Fig. 4, on an arm pivotably supported in a disc 46 on a tubular shaft 45 in the drive to the device 29, the arm bearing against an adjustable stationary body 51. The eccentric is coupled to a disc 48 which can be connected to the shaft 34 by a dog clutch 49. In another embodiment, the correcting device of a thin walled tube 62, Fig. 7, which can be deformed by adjustable shoes 65 carried by a stationary ring 66, the tube being engaged by a follower arrangement 70 which transmits both the continuous rotation and the variation in the angular velocity. In a further embodiment, the variation is effected by periodic relative axial movement between a pair of helical gears.