Patent GB-907809-A (GB)
Title: Improvements in or relating to machine tools
Inventor: FENN RAYMOND TURNER
IPC: H01M4/98
Filed: 1959-10-08
Abstract: 907,809. Copy-turning. FISCHER A.G., GEORG. Oct. 8, 1959, No. 34147/59. Class 83 (3). A machine tool comprises manually-operated switches 121-126 for selecting the number of roughing cuts to be taken and the cutting- depth for each cut, and automatic means for performing the cuts, for making a templatecontrolled finishing cut and for returning the depth-determining devices to zero. The template 40 is mounted on a bar 37 carried between adjustable centres 38, 39. It is engaged by a follower 36 acting through a valve 33 which controls the supply of fluid from a pump 42 to either side of a piston 21 attached to the slide 17. A cylinder 24 forming the tool-slide is thus moved on the piston 21, the slide carrying one or more tools or boring-bars as required. The initial position of the tool-slide is set by a screw 31. The follower 36, carried on a pivot 35, is biased away from the template by a spring 58 acting through levers 52, 54. The lever 54 can be rendered inoperative by movement of a piston 100 which moves a link 70 to compress the spring. A spring 29 then moves the valve 33 so that the tool-slide moves upwardly until the feeler contacts the template 40. The limits of movement of the slide 24 are determined by stops 67, 80 which are adjusted by wheels 83, 84 and screws 81, 85. The stop 80 thus controls the maximum depth of cut, and can be set automatically by a motor 90 rotating a shaft 93 carrying a cam 97 to operate a counting device 98. One revolution of the cam is equivalent to a tool advance of 1 mm. The shaft 93 also carries a clutch 95 and a brake 96. At the end of a return traverse of the slide 17, a switch 107 is operated by a dog 105 and a switch 109 is operated either by a dog 108 or by the dog 105 to adjust the cut and reverse the saddle movement. When a workpiece is finished, the slide 17 is returned by a stop 110 engaging a switch 111. This switch also prevents over-travel on intermediate cuts. To prevent the tool being withdrawn to a position beyond the greatest required diameter of the work, a switch 114 is provided. When actuated by a cam 113, the switch 114 causes automatic fast return of the slide 17 to its starting position. The depth of the first roughing cut is determined by the initial position of the stop 80. The depths of up to five more cuts are selected on switches 121 to 125, Fig. 5. A further switch 126 selects the number of roughing cuts to be taken. A stepping switch 150, Fig. 3, adds up the cutting depths so that, when cutting is complete, the tool can be returned to its initial position. In operation, the main motor is started by a push-button and the headstock spindle is coupled thereto. A switch is set to automatic operation and a cycle start push-button is depressed. Thereby the rod 70 is moved to release the lever 52, and the slide 24 moves in until the lever 52 abuts the stop 80. A roughing cut ensues until the tracer 36 abuts a shoulder 115 on the template 40. The template 40, Fig. 1a, is in an electrical circuit and is mounted in an insulated sheath 117, the circuit being completed when the tracer contacts it, causing the slide 24 to be withdrawn as determined by the stop 67. The switch 114 is then operated and the slide 17 is returned at fast speed. The arm 151 of the selector switch 150 and the arm 141 of a selector switch 140 are advanced until the arm 141 engages the contact 175 selected by the switch 121, the selector 121 itself having been selected by a stepping switch 130. The motor 90 thereby advances the stop 80 three increments and is then braked. When the switch 107 abuts the dog 105, the tool slide is again fed in, the slide 17 is moved at feed-speed and the stepping switch 140 is returned to zero. Cuts are made in succession until an arm 132 of the stepping switch 130 reaches a contact selected by the " number-of-cuts " selector switch 126 and causes the slide to be returned and the electrical circuit of the template to be rendered inoperative. When the slide 14 is again advanced, therefore, the tracer contacts the template 40, the stop 80 being advanced clear of the arm 52 by allowing the selector-switch arm 141 to advance to a contact 178. The finishing cut is thus controlled hydraulically by the template. Specifil processes. When cutting a tapered workpiece, Fig. 6, the roughing cuts are taken as shown.