Patent GB-579611-A (GB)
Title: Improvements in or relating to lathes
IPC: B23Q35/18
Filed: 1944-06-05
Abstract: 579,611. Lathes. AKT.-GES. DER EISEN-UND STAHLWERKE VORM. G. FISCHER. June 5, 1944, No. 10803. Convention date, May 15, 1943. [Class 83 (iii)] A copying-lathe having a tool slide which is carried by a longitudinal slide so as to be reciprocable in a vertical plane and which is fed at an acute angle to the movement of the longitudinal slide is characterised in that two tools are arranged on the tool slide and are fed in opposite directions to each other and can be advanced by means of a hydraulic feeding device which is adapted to operate in both feed directions of the tools in such manner that the work is machined in two successive traverses in accordance with complementary templates secured to the machine frame. The machine frame 1 carries a longitudinal slide 2, Fig. 2, on which is pivotally mounted at 5, a plate 4 on which is guided a slide 3 carrying tools 23 and 26. The plate 4 is normally in such a position that the tool slide 3 is inclined. The slide 2 houses an oil reservoir and a pressure pump 6 which supplies oil by way of a pipe. 7, an annular channel around the pivot 5, and a pipe 8 to the space 10 beneath a piston 9 integral with the plate 4. From the space 10 the oil passes through a pipe 11, and a reducing valve 12 which maintains a constant pressure in the space 10, to a control device 15 carried by the slide 3. If the control device is open, the oil returns to the pump chamber by way of pipe 32. The control device 15 comprises a reciprocating valve member urged downwardly by a spring 18 and restrained by an arm 16 pivoted at 17 and at its outer end forming a feeler member of rhombic cross-section adapted to engage one or other of the templates 24, 27. Beneath the member 15 on the other side of the arm 16 is a.member 30 urged upwards by a relatively stronger spring 21 under the control of a screw 22. By unscrewing this screw the spring 21 may be fully expanded and become inoperative. In this position, the spring 18 moves the member 15 to close the oil passage and pressure then builds up in the chamber 13 above the piston 9 and the slide 3 rises until the feeler 16 engages the template 27. The slide 2 is then traversed longitudinally and the tool 23 operates on the work 25 under the control of the template, the position of the slide 3 being continually adjusted as the control device is moved to close or partially open the oil passage. At the end of the traverse, the screw 22 is operated to compress the spring 21 which then urges upwards the member 15. This relieves the pressure in the chamber 13 and the slide 3 descends until the feeler 16 engages the template 24, the work then being operated on by the tool 26. In a modified form for machining internal contours, Fig. 3, two oppositely disposed tools 51, 52 are carried by a holder 50 parallel to the axis of the work 53 and supported from the inclined slide 43. The paths of the tools under the action of the templates 48, 49 are indicated by dotted lines in the Figure. A hand-wheel 56 allows movement of the feeler 47 to be manually influenced if desired. In a modified form, the spring 21 may be rendered inoperative by a cam 79 instead of by the screw 22. In another modification, Fig. 8, the feeler 71 is forked and carries control edges 72, 74 adapted to engage the upper and lower edges of a finished workpiece 76 which is used as a template.