Patent GB-722939-A (GB)
Title: Improvements in apparatus for producing shaped members and/or for checking the shapeof members
IPC: B24B17/02
Filed: 1952-07-08
Abstract: 722,939. Electrolytic shaping of articles. TOOLMASTERS, Ltd., HALLEWELL, H. S., and PORTER, C. B. A. June 29, 1953 [July 8, 1952; Aug. 1, 1952], Nos. 17239/52 and 19556/52. Class 41. [Also in Groups XIX, XXII and XXIII] Apparatus for the electrolytic shaping of articles and in which the electrolytic process may be combined with mechanical machining, such as turning, milling or grinding, (see Groups XXII and XXIII), comprises a headstock 6, Fig. 1, or a headstock and tailstock, and means for moving at least the headstock, or the tailstock where present, so that the axis of its spindle 1 describes a path in accordance with the profile to be imparted to the workpiece a the end thereof adjacent the headstock or tailstock, the means comprising pantograph mechanism 7, 10, 12, 14, 15 and 16, Fig. 3, of which the spindle forms the follower and the tracer is so constrained that the axis of the spindle describes the required path. The constraining means for the tracer includes a grooved or ribbed cam 22 which is secured for angular adjustment to a face plate 21 mounted on a spindle 20 and engaged by two rollers 30, Fig. 7, carried by a slide 29, and a fixed roller 31; the slide is connected by a lever 33 to a hydraulic ram 32 which urges it downwardly so that the rollers are held in firm engagement with the cam. As shown, the cam 22 is designed to impart an aerofoil section to the work, which may be a turbine blade, adjacent the headstock end. The tailstock spindle may be moved in a similar manner and a twist obtained along the length of the work by arranging its driving cam at an angle to the cam 22. A roller chain 28 screwed or riveted to the cam face is driven by a sprocket 37 connected by chain drives 66, 67 mounted on pivoted links 40, 46 with a sprocket 50 mounted on one end of a shaft 48 carried by a column 49, Fig. 4, the other end of the shaft carrying a gear-wheel 51 in mesh with a gear-wheel 52 mounted on a pivoted arm 54 and driven by a hydraulic motor 56 through reduction gearing and chain drives 58, 65. The spindle 20 is driven by the cam 22 and connected by a further set of chain drives 70, 73 and 76 with the headstock spindle 1 which has a driving dog 3 for engagement with a recess in the work. The peripheral speed of the work may be varied in accordance with its curvature by causing the slide 29 to operate a valve controlling the fluid supply to the motor 56. The tool head is mounted on the column 49 which may be displaced vertically by a hydraulic ram 96 and may comprise an abrasive band 78 driven by an electric motor 80 mounted on a pivoted housing 88 loaded by a hydraulic ram 91 to tension the band. The lower end of the band passes over rollers 81, 82 and 83, mounted on a carriage 87 which is reciprocated horizontally on the column 49 by cams 114, 115, Fig. 5, acting through levers 117, 123, toothed sectors 120, 125, Fig. 4, pinions 121, 129 and racks 126, 127 which are adjustably secured to the carriage to permit the range of movement to be varied. Each cam serves to displace the carriage in one direction only from a central position to which it is returned by a hydraulic ram and is mounted on a shaft 116 driven through worm gearing and a chain drive from the motor 56 so that the abrasive band traverses the workpiece completely once during each revolution. A dwell may be provided at the end of each traverse. The band is moved rapidly towards the workpiece by the ram 96 until a manually-adjustable rod 108 carried by the column 49 engages a stop 97 which is permitted to descend slowly by a cam 107 connected with the stop by a lever 100 and rotated by a rack and pinion drive from a hydraulic ram 104 controlled by a throttle valve. The shape of the finished workpiece may be checked by providing a number of dial indicators in line with the headstock and tailstock centres. If the workpiece is accurate the indicators show no variation as it is rotated. The abrasive band may be replaced by a grinding wheel and the chain drives by gearing which incorporates universal couplings. The Provisional Specifications describe a variable-speed chain drive for the headstock and tailstock cams which includes a pair of sprockets mounted on a scissors device so that they are moved relatively to one another by the motion of the cams to control the speed of the chain driving sprocket and state that the ram 96 may be controlled by a time-delay switch.