Patent GB-524518-A (GB)
Title: Improvements in or relating to the finishing of surfaces by abrading
IPC: B24B33/02
Filed: 1939-01-31
Abstract: 524,518. Finishing surfaces. CHRYSLER CORPORATION. Jan. 31, 1939, No. 3287. Convention date, July 16, 1938. [Class 60] In a method of finishing a workpiece surface, the same parts of the area of the surface are acted on alternately by coarse and fine abrading elements operating in a repeating cycle. In one form, particularly for finishing engine cylinders, the work 12 is mounted on a table 11 and the tool elements are mounted in a carriage 16 which may be moved to and from the work by a cylinder 17. The tool spindle 23 is driven by worm gearing 26. The upper part of the spindle has a bearing in a collar 29 which is vertically reciprocated by an eccentric 33 driven by a motor 34. A second stage of axial reciprocation may be imparted to the tool by the cylinder 17. The tool spindle has a socketed upper part in which the tool is secured by a screwed ring 43. The tool comprises a number of universally pivoted sections 52, 62, the latter forming the tool body and having spaced axial slots 63 carrying blocks 64, 65 fitted with fine abrading elements 68 and rougher abrading elements 69. Blocks 64<SP>1</SP> of fibrous material are fitted in the tool body between the slots. A pair of concentric cam members are fitted in the tool body, the inner one 78 serving to engage the blocks 65 and urge them outwardly against spring pressure and the outer one 77 urging outwardly the blocks 64. The cams may be moved axially independently in a predetermined cycle by cylinders 86, 87 having pistons 88, 89 which are urged upwardly by springs 90, 91. The piston rods are in sections and their connections to the cams allow universal movement. Provision is made for predetermining the stroke lengths and limiting positions of the cams 77 and 78. The cylinders 86, 87 are supplied with fluid through a control valve 136. When this valve is in the Fig. 8 position, fluid is cut off from the lines 141, 143 leading to the upper ends of the cylinders and both sets of abrading elements are withdrawn by the springs 90, 91. During rotation of the valve, first the pipe 141 is opened to lower the piston 87 and feed the elements 69 outwardly. After a predetermined time, fluid is admitted to the line 143 and the second cam member is moved downwards to actuate the elements 68. Further rotation of the valve first withdraws the elements 69 and then the elements 68. The valve body is driven through worm gearing from a motor 144 through switch means arranged to stop the motor when the elements are all retracted for removing the tool from the work. The motor is switched on again by means responsive to the position of carriage 16 on its vertical support. In a modification the cylinders 87, 86 may be supplied with fluid under manual control. The lubricating coolant may be supplied by a pipe 200. The Specification as open to inspection under Sect. 91 describes also a method of and apparatus for finishing a surface by removing all irregularities lying above a predetermined datum line by regulating the abrading pressure in relation to the strength of the oil film between the abrading means and the surface. The work may be pre-cooled to a temperature between 50‹F. and -10‹F. This subjectmatter does not appear in the Specification but forms the subject-matter of Specifications 524,519 and 524,520.