GB680479A - Improvements in or relating to cutting and shaping machines - Google Patents

Abstract

680,479. Grinding. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. April 12, 1951 [April 13, 1950], No. 9177/50. Class 60. [Also in Groups XXII and XXIV] In a copy-grinding, -milling or -planing machine particularly for making turbine blades, the relative feed movement (arrow A in Fig. 2) in the direction of cut is accompanied by a relativeoscillatory or reciprocatory movement (arrow B in Fig. 4) in the direction of traverse of a frequency which is high compared with the rate of feed and is of an amplitude not less than each increment of traverse so that the cuts form a series of overlapping bands without leaving. ridges. The oscillatory movement may be achieved by mounting a rotary cutter 1 or a number of cutters and follower 2 in swash-plate fashion, either on a single shaft 3, Fig. 1, which is urged towards the work 4 and model 5 by a spring or gravity, or on separate driven shafts 16, 17 mounted in a frame 14 pivoted about the main driving shaft 15; to vary the movements of the work and model if they are of different sizes, the table may be as described in Specification 631,248. Alternatively, a reciprocatory motion may be given to the pattern and work table 36, Fig. 4, by a lead screw 37 which is given part turns in one direction alternatively with smaller movements in the opposite direction by oppositely-acting ratchets 40, 41 driven by an oscillating lever 45 and gearing 42, 43 of slightly different ratios. Since the tracer slips sideways on the model, it will surmount abrupt portions more readily than one simply rolling by friction.