Patent GB-793366-A (GB)
Title: Improvements in machines for polishing or lightly grinding elongated work-pieces
Inventor: DAVIS BERNARD VICTOR
IPC: B24B21/00
Filed: 1954-12-07
Abstract: 793,366. Copy grinding. ARMSTRONG SIDDELEY MOTORS, Ltd. Nov. 14, 1955 [Dec. 7, 1954], No. 35354/54. Class 60. A machine for polishing or lightly grinding a curved surface of an elongated workpiece, e.g., a gas-turbine compresser blade comprises a vertically-movable slide 14 carrying a polishing head 19 and a follower roller 20 the latter cooperating with a former 47. The slide 14 is movable in a vertical channel-section member 13 secured to the base 10 ; the slide 14 is bolted to a lower slide 15 vertically slidable in guides in the pedestal 11. At its upper end the slide 14 carries two arms 17, 18. The rotatable partspherical follower roller 20 is carried by the arm 17 which is vertically adjustable on the slide 14 by a manually operated screw 23. The arm 18 is integral with the slide 14 and carries the polishing head 19 which comprises a rotatablymounted pulley 27 to which is bonded rubber 30 having a part-spherical surface ; a polishing band 32 coated with emery passes around the pulley 27, around pulleys 34, 35 carried by the slide 14, and around a driving pulley 36 driven by an electric motor 37 carried by the lower slide 15, an adjustable spring-pressed jockey pulley 38 being provided. Counterbalance weights 43 are attached to a cable 44 passing over pulleys 45 and connected to the lower slide 15. The follower roller 20 co-operates with a former 47 mounted on a fixture 47a supported on a former table 49 slidable longitudinally on a table carrier 52. The carrier 52 extends across the machine; beneath the polishing head 19 it supports a longitudinally slidable work table 54 which supports a fixture 21a carrying the workpiece 21. The work table 54 also supports an oil bath 60, the workpiece being totally immersed in the oil which retains the dust produced. The former table 49 and worktable 54 are integrally connected together at their ends 53 so as to slide longitudinally in unison. The table carrier 52 is movable transversely on the base 10. In operation, the tables 49, 54 are reciprocated longitudinally with automatic reversal and the table carrier 52 is automatically intermittently moved transversely. Compressed air supplied at 78 passes through filter 79 and lubricator 80 to point 68. For effecting the longitudinal reciprocation, the air passes from point 68 through regulator 69, through manuallyoperated on-off valve 70, through automaticallyoperated valve 73 to a distributing valve 74 and then into one or other of chambers 63, 64 to displace oil therefrom into a cylinder 62 containing a piston 62a connected with the table 49 ; the rate of movement of the table is controlled by manually adjustable restrictions 77. The valve 74 is reversed by compressed air under the control of valves 75, 76 operated by dogs 75b, 76b on the table 49 to give automatic reversal. The valve 73 is operated by an adjustable stop 73a at the completion of a cycle of operation. A manually-engageable and operable handwheel 92 drives a pinion 104 engaged with a rack 105 for manual longitudinal movement of the tables 49, 54. For effecting the transverse movement, the air passes from point 68 through regulator 69, through valve 71 operated by a stop 71a on the table 49 when the latter reaches the centre of its stroke, and through manually-operated on-off valve 72 to a single-acting cylinder 65 containing a piston carrying a pawl 67 co-operating with a ratchet 66 fast with a lead screw 102 on the table carrier 52 engaging a nut 103 on the machine table 10. Movement of the piston is limited by a stop 97 indexed by a knob 102a and having four different stop surfaces 98-101. A manuallyoperable handwheel 91 on the lead-screw 102 serves for transverse adjustment of the tables 49, 54 for setting-up. The slides 14, 15 are moved vertically at the beginning and end of a polishing operation by a piston 86 positioned beneath the lower slide 15 and working in a cylinder 85 supplied with compressed air under the control of a manually-operated distributing valve 81 ; a device 84 permits free flow of air to the lower end of the cylinder for raising the slides rapidly but adjustably throttles the exhaust of air during the lowering of the slides which takes place slowly. A cover 61 is provided. According to the Provisional Specification, the cover is interconnected with switches controlling the motor and pneumatic-hydraulic means so that when the cover is raised the machine is inoperative ; an additional trip mechanism is provided operable by the arm carrying the polishing head when the workpiece is completely polished to raise the verticallyslidable member.