GB667407A - Machine for polishing convex surfaces in particular the rims of bicycle, tandem bicycle and the like vehicle wheels - Google Patents

Abstract

667,407. Polishing bicycle rims &c. ETABLISSEMENTS PIERRE LYOTARD. July 18, 1949 [April 14, 1949], No. 18888/49. Class 60. A machine for polishing convex surfaces, in particular of the rims of bicycle, tandem bicycle and like vehicle wheels, comprises a frame carrying a rim-supporting ring that is adapted to pivot round a vertical axis and having a prop bearing against a bearing plate on the frame, said ring carrying a plurality of similar rubber rollers each having a convex periphery the radius of which is equal to the radius of the outer concave surface of the rim, at least two of these rollers being used for the driving of the rim and being driven by a motor secured to the ring while at least one of said rollers bearing against the rim may be shifted radially by a cam system, the rim thus being constrained to assume a continuous rotation and the ring at the same time executing an oscillation round its pivotal axis while the grinding wheel engaging the rim rotates in a direction opposed to the rotation of the rim. The rim 4 to be polished is rotatably supported by rubber rollers 6, 7, 8 carried by a ring 3 having a tubular member 3' pivoted on an upright 2 the base 2' of which is secured to the machine frame 1; a portion 3<SP>2</SP> of ring 3 opposite part 3' has an adjustable screw co-operating with a bearing plate 5 on the frame 1. The rollers 6, 7, 8 have convex peripheries of the same radius of curvature as the outer concave surface of the rim 4. A motor 9 carried by the ring 3 drives the rollers 6, 7 through belts; the roller 8 is carried by a rod 11, Fig. 4, movable upwardly to release the rim by rotating a part 12 having cam surfaces co-operating with cam surfaces on a fixed part 10. The pivotal axis of the ring 3 intersects the axis of rotation of the roller 6. A slide 16, movable longitudinally on slideways 14 by handwheel 15 has transverse slideway 16<SP>1</SP> for a carriage 17 provided with a bearing 18 for the shaft 19 of a grinding wheel 13 driven by motor 20 through belts. During polishing, the grinding wheel 13 is axially reciprocated by a cam 22 working in a slot 17<SP>2</SP> in a lateral extension 17<SP>1</SP> of the carriage 17, the cam 22 being driven by a motor 23 through belts and bevel gears 25, 26. A spring 31 anchored at 32 to the machine frame 1 is secured to the ring 3 and holds it in contact with an adjustable stop 30 screwed in a bearing 29 on a projection 28 from the carriage 17 so that as the latter reciprocates the ring 3 is simultaneously oscillated whereby all of the inner convex surface of the rim 4 is presented to the periphery of the grinding wheel 13 which departs from cylindrical shape at its ends so as to engage the rounded lateral sections of the rim.