GB524519A - Improvements in or relating to finished surfaces, and method of and apparatus for finishing surfaces - Google Patents

Abstract

524,519. Grinding and polishing. CHRYSLER CORPORATION. Jan 31, 1939, No. 3288. Convention date, July 29, 1938. [A Specification was laid open to inspection under Sect. 91 of the Acts, Jan. 17, 1940.] [Class 60] In a method of and apparatus for finefinishing the surface of a work-piece the workpiece is subjected to a fine abrasive action while it is at a temperature substantially below normal room temperature so that it may withstand scratching by the grit of the abrasive element. In one form the work such as a cylinder 15 is mounted between centres 13, 14, on a bed 11 which is reciprocated longitudinally from a motor 21 through a crank-disc 19 and link 20. The work is rotated from a motor 18 through gearing 17. The tool-head 27 is mounted on the end of a lever 32 pivoted at 33 and urged to engage the tool with the work by a spring 45. An adjustable counterbalance 34 acts in conjunction with the spring to adjust the pressure between tool and work. The tool motor 28 has a spindle carrying an eccentric pin which reciprocates a slide block 39 in a direction parallel to the work axis. The finishing tool-block is pivoted to the slide block on a transverse pin 43 and the block is reciprocated through a short stroke at high speed while the bed 11 is slowly reciprocated. The work may be precooled to a temperature between 50‹F. and 10‹F. in a container maintained at the required temperature by dry ice or other means then placed between the centres and kept cool during operation by coolant which is pumped from a container 57 by a pump 59, supplied to the work by a line 62 and collected for return to the tank in a trough 64. The tank is cooled by a coil 53 forming part of a refrigerating system operated by a compressor 50. In some cases the work may be sufficiently cooled by the coolant only. In a modification, Fig. 3, a refrigerating tank 68 is mounted on the carriage 11 and the work is partly immersed in the coolant which may be cooled by dry ice 49 or by a refrigerating coil. The coolant is withdrawn from the tank 68 and pumped over the work whence it returns to the tank. In another modification the entire finishing apparatus is disposed in an enclosure which is cooled by cold air circulation or by a refrigerating coil or both.