Patent GB-882859-A (GB)
Title: Machine for abrasive finishing of contoured or profiled surfaces
IPC: B24B35/00
Filed: 1959-06-20
Abstract: 882,859. Fluid-pressure servomotor-control systems. ARMYTAGE, F. W. June 20, 1960 [June 20, 1959], No. 21232/59. Class 135. [Also in Group XXIII] A method for the abrasive finishing of contoured surfaces of workpieces consists in moving the contoured surface of the workpiece and the tool relative to one another under automatic control of an hydraulic tracer valve whose movements are actuated by the tool acting as a stylus or tracer foot. The machine frame 1 supported on wheels 2 contains a reservoir from which oil is delivered by a pump 5, driven by an electric motor 4, to a motor 6 driving, through a belt, the shaft 10 of a circular magnetic work-table 11. The work-table can be rotated in either direction continuously or oscillated under the control of reversing mechanism 12 operated by dogs inserted in a reversing disc 15 secured on the shaft 10. Above the work-table is a head 16 vertically reciprocated on pillars 17, 17, 17 by the rod 18 of a ram working in a cylinder 19 supplied by the pump 5. A dog 25 on the head 16 cooperates with adjustable stops 24, 24 on a rod 20 centralized by springs 21, 21. The rod 20 has pins 26, 26 co-operating with the actuator bar 27x of reversing mechanism 27. The ram may have different speeds on its upward and downward strokes. The head 16 carries a saddle 28 having an annular T-sectioned slot 29 in which engage the heads 30 of studs secured in a tool slide 31 so that the tool slide can be adjusted angularly relatively to the head through 360 degrees. The saddle 32 of the tool slide 31 is reciprocated by a ram working in a cylinder 33 under the control of a tracer valve 34, preferably constructed as in Specification 692,642. The tracer valve is secured by its stem 35 in a bracket 36 secured to the saddle 32 by a stud 37, so that the bracket can be adjusted angularly relatively to the saddle through 360 degrees. An arm 38 is pivoted at one end in the bracket 36 by a pivot-pin 39 with ball-bearings 40. The arm near its other end works between guide rollers 41, 41 mounted on the bracket 36. Mounted in the bracket 36 is a spindle 42 whose foot is urged into contact with the arm 38 by a coil spring 43x surrounding the spindle within a sleeve 44 screwed into the bracket by a knurled head 45 to compress the spring, so that a predetermined constant pressure can be exerted upon the arm 38, downward movement being limited by a stop-pin 46. The spindle 42 has a nose-piece 47 making point contact with a stud 48 in an arm 49 which actuates the tracer valve 34. The arm 38 has alternative sockets 50, 50a, 50b to receive the shank of a honing or like tool 51a in the form of a spindle having applied to or secured on its foot, on the side facing towards the arm pivot and/or on its end a stone or other suitable form of abrasive element. The socket 50b is provided in an arm 52 pivoted at 53 on the arm 38 and adjustable through 90 degrees by a clamping stud 54 working in a segmental slot 55. The socket 50 may be used for internal honing of workpieces such as the bottle mould W1. The socket 50a may be used for external honing of suitable workpieces. By securing the tool in an adaptor 56 or 56x in turn secured in the socket 50b the tool can be made to approach the work at the most suitable angle as in treating a hemispherical workpiece W2, Fig. 10, or treating the inside of a cupshaped workpiece W3, Fig. 11; the bracket 36 has been angularly adjusted by itself and/or by the angular adjustment of the tool slide. The speeds of the work-table 11 and the head 16 are adjusted by control knobs 60, 61 giving infinite speed variation over a predetermined range. In operation, movement of the tool foot in a direction altering the loading of the spring 43x actuates the valve 34 to render the cylinder 33 effective to move the saddle 32 in the appropriate direction so that the loading is restored to its preset value. In a modification, Figs. 8 and 9, a turret 62 secured in any of the alternative sockets in the arm 38 is adapted to hold three tools, e.g. roughing, medium and finishing hones, any one of which can be brought into working position and locked there. The workpiece W4 is held on a saddle 63 reciprocated, by the ram of an hydraulic cylinder 64, on a work-slide 65 secured upon the machine frame 1.