| 摘要 |
889,426. Grinding. IMPERIAL CHEMICAL INDUSTRIES Ltd. March 16, 1960 [March 16, 1959], No. 8954/59. Class 60. A machine for lapping plane surfaces comprises a horizontal table 14 which is mounted for reciprocation in its own plane and has an upper true surface 16 adapted to act as a lap for articles placed thereon. The machine may consist of one or two tables which are of soft cast-iron formed with shallow grooves to assist the distribution of an abrasing medium, such as silicon carbide in oil. The tables are mounted on balls 4 located in guides 3, 13 and are reciprocated at between 100 and 200 complete reciprocations per minute by cranks 5 driven by an electric or fluid-operated motor, the amptitude of the stroke being between 1 inch and 2 inches. The articles to be lapped, such as the discs or wedges of gate valves, are placed on the upper surfaces and relative movement between the articles and surfaces is effected by the inertia of the articles. The articles are retained on the surfaces by upstanding edges 17 which are covered with a resilient material so that as articles approach the edges they rebound therefrom.
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