GB1167556A - Machine for Precision Machining and Finishing the Surfaces of the Cavity of a Die and the Like - Google Patents

Abstract

1,167,556. Machine tool for machining die cavities and punches; polishing. MARKGR€FLICH BADISCHE INDUSTRIEVERWALTUNG G.m.b.H. 25 Sept., 1967, No. 43590/67. Headings B3B, B3D, B3K, B3L and B3T. A machine particularly intended for planing and polishing the internal faces of a polygonal cavity of a die to be used for cold forming nuts, or the faces of a matching punch, comprises a chuck 6 which is rotatable about the longitudinal axis of the workpiece 7 and which is indexible into angular positions corresponding to the faces to be machined, and a tool holder 4 including a tool 9 with cutters mounted to oscillate about an axis 10 normal to the machined flat surface within a preadjustable lateral amplitude and associated with means for feeding the tool in the axial direction of said cavity. The oscillatory motion of the tool holder is preferably generated by means of an adjustably eccentric disc 19 carried by a rotary disc 20 driven by motor 46 through flexible drive means 45. The tool holder and the eccentric drive discs are mounted on a longitudinal slide 15 mounted on a cross slide 23 supported by a member 25 which is tiltable about a pivot 26, the whole being vertically adjustable on columns 29. Feed motion of the slide is derived from a motor 49 through worm gearing 52 which is disengageable to allow the slide to return under the action of a spring 54 and under dashpot control (Figs. 8, 9, not shown). An adjustable stop 63 engageable with a stop switch 65 can be used for predetermining the extent of infeed of the tool. The chuck 6 is carried in a spindle head 70 by a spindle 68 which carries also a notched index plate 69; a manually engageable and disengageable sliding detent 90 co-operates with the plate 69 to arrest the chuck and workpiece in the desired angular position. The detent 90 is mounted on the spindle head 70 for slight pivotal adjustment so as to allow for slight angular adjustment of the index positions in which the chuck 6 and workpiece are located. The entire spindle head is pivotable about a pivot 72 and also about a vertical axis on the spigot 73. Provision is also made for longitudinal adjustment of the frame member 5 on which the spindle head is mounted, by means of a manually operated rack and pinion 79, 80. With the detent 90 withdrawn the spindle 68 and chuck 6 may be rotated by belt drive 99 from a motor 98 so that the machine may be used for turning or polishing, e.g. an end face of the workpiece. The tool 101, Fig. 10, may be shaped to provide two cutting edges 105 and particularly two forward cutting points 109. Alternatively a diamond pointed tool (Fig. 15, not shown) may be used or a polishing or grinding tool 9b having grooves 113 extending transversely of the direction of oscillation and adapted to receive a grinding or polishing paste. It is stated that a conventional grinding or milling attachment can be mounted on the toolholder, e.g. for machining a bevel edge on the end surface of a workpiece.