GB746543A - Improvements in or relating to apparatus for machining a gradually changing angular edge on an irregular work piece - Google Patents

Abstract

746,543. Copy-milling. BRIDGWATER MACHINE CO. Feb. 15, 1954, No. 4389/54. Class 83 (3). Apparatus for machining a gradually changing angular edge h on an irregular workpiece A, Fig. 15, comprises a movable and rotatable work-table 6, Fig. 1, a rotating cutting-tool 205 on a carrier 155 pivotally mounted on a head 70 projecting over the table, driving connections between the carrier and a follower 258 contacting a rotary cam 240 to vary the angular position of the tool, a template 41 on the table 6 for moving the axis of the table to and from the tool, and means for rotating the table and cam in synchronism so that the tool follows the shape of the template. One or more workpieces A, Figs. 13 and 17, roughly forged to shape but having excess metal e, are secured on the rotatable table 6 by clamps 37, a spacer f being interposed between them. The table is mounted by balls 5 on a slide 4 which is moved by a double-acting piston 24 adjustably clamped thereto by a collet 25. The table 6 also carries two templates 41, 42, the first being used to trim off the excess metal e and the other to machine the bevelled edge h. The templates are contacted in turn by a follower 62 connected to a tracer valve 56 which controls the piston 24 to move the table to and from the tool 205. The tracer valve may be adjusted by a screw 57 on a horizontally-adjustable slide 52 on a vertically adjustable slide 48. The slide 48 is carried on a vertical column 45 secured to the bed 1 and open at the rear. The column also carries the head 70 which is adjustable vertically by a hydraulic piston-andcylinder supplied with pressure by a pump which also supplies pressure to move the tool carriage. Lock-nuts 91 hold the piston-rod 88 in an adjusted position until the head is clamped to the column. Within the column 45 is a motor 100 which rotates the table 6 through gearing 107, 110, a shaft 20 and bevel gearing 12, 14. The shaft 20 is also connected to a shaft 120 by a manually-operated clutch which is disengaged when setting-up the machine by a hand wheel 142. The cylindrical milling-cutter 205, Fig. 3, has reduced ends which are mounted respectively in a bearing 207 in an outboard support 211 and in the spindle 190 where it is secured by a screw 206. The spindle 190 is mounted in a sleeve 178 secured by opposing screw-operated wedges in the tool-carrier 155 formed with trunnions 152, 165. The spindle is rotated by a pulley 202 and belt 203. The carrier 155 is rocked about its trunnions to incline the cutter according to the angle of bevel required on the edge of the work by the cam 240 fixed by set-screws 244 to a shaft 243 rotated through change-gearing 134, 132 by the shaft 120. The cam 240 is engaged by the tracer 258 which may be locked in an inoperative position by a screw 301 when the cutter is locked in a vertical position for the preliminary cutting operation in which it removes the excess metal e. The tracer is adjustable laterally by a screw 281 on a slide 260 to which is adjustably connected a plate 274, Fig. 3. The plate carries tapes 224, 225 secured to a sector 218 on the carrier. Rotation of the cam 240 causes longitudinal movement of the follower and thus of the plate 274, so rocking the tool. The tracer is rotatably mounted and is held against one side of the cam-groove 241 by a pneumatic device 305, 310 attached to an arm 312 on the slide 260. When the cutter is vertical to take the preliminary cut, the slide 260 is held rigidly by lock-nuts 316 on a threaded rod 315 passing through the arm 312. A lever is pivoted on a bracket 324 attached to the slide 260 for manually-controlling the movement of the toolcarrier.