GB149401A - Improvements in or relating to copying lathes or the like - Google Patents

Abstract

149,401. Wade, H., (Fitz-Empire Double Pivot Last Co.). May 7, 1919. Lathes.-Duplex copying-lathes, particularly applicable for last-turning, are designed to embody a special length-grading mechanism. The slides comprise bars 20, ribbed at 18 to engage roller bearings 14, 16 forming an inclined guideway in the main frame, felt wipers 36 being provided to exclude cuttings. An additional guide is provided at 30. The bars are formed integral with triangular end frames 24 connected by two tubular cross-bars 26 that support adjustable headstocks 52, 54 and tailswcks 56, 58. Right and left hand last blocks are supported by 54, 58 and the model by 52, 56. The bars 20 are linked to arms connected by a rock shaft 42, provided with a third arm carrying a small adjustable counterweight. The arm may be set on either side of the shaft in order to oppose or assist the descent of the slides in the inclined guideway to maintain the model in contact with the tracer. The main slide 148 carrying the cutters moves on the bed by a vee 150 and plane surface 152, and is fed by a rack 168 and pinion geared to a combined hand and worm-wheel driven through a dropping worm 174, cone pulleys and belt from a shaft in the main gear box direct connected to an .electric motor. The cutters are mounted on the rotor shafts of two other motors adjustably mounted in the slide 148. The model wheel 234 is mounted on an adjustable slide 236 connected to the width-grading mechanism 166, 164, 162 shown in part and of ordinary design. The slide 236 is carried by a slide 158, 160 in ways on the main cutter slide and connected to it through length-grading mechanism comprising ways 196 bolted to the, cutter slide and receiving a slide 198 moving equally to the cutter slide but at right angles thereto as controlled by rack-andpinion gearing 216, 220, 218. Rigidly connected to the slide 198 by arms 200, 202 is a slide 192 pivoted at 204 and clamped at 207 in the arcuate slot 206. The guideway for the slide 192 is angularly adjustable on the model wheel slide. A scale 208 is graduated in last sizes, the actual dimension being some convenient multiple of the true length, and is so arranged that the zero of its graduated edge would coincide with the axis 204. A slider 210 on the scale 208 carries an inclined scale 212, having its zero on the graduated edge of the scale 208, and so graduated that the projected length of one size on the scale 208 is equal to one size division on that scale. In use, the slider is set with the zero at the division corresponding to the model length, and the slide 192 is set so that the radial edge of a straight edge 214, carried by it, intersects the scale 212 at the graduation corresponding to the number of sizes up or down that the lasts are required to be. The worm 174 is tripped automatically by means not described after one traverse, and the grading-mechanism is so arranged that the pivot 204 is then co-axial with that of the guideway in order that adjustments may conveniently be made. The main gear box 92 also drives through a friction clutch 96 engaged by an ad'- justable spring, a shaft driving a co-axial shaft 107 through a dog clutch 104 and transmitting through an adjustably tensioned chain 144 to a wheel 88 on a stub shaft seared to a shaft 60 carrying one driving centre 66 and geared by two pairs of equal wheels to the other driving centres 72, 80. The slide 148 may be drawn back, so that the cutters are clear of the blanks, and locked by a spring plunger 40. In this position a pin carried by a fourth arm on the rock shaft 42, and normally moving idly in a curved slot in a slide, engages an adjustable stop in the end cf the slot and moves the slide, causing a roller to come into operative relation with a cam disk 116 geared to the shaft 107 and thus to open the clutch 104. The gearing is so arranged that the driving centres always tend to stop in the same angular position, that most favourable for changing the work.