Patent GB-829906-A (GB)
Title: Improvements in or relating to copying lathes and like machine tools
IPC: B23B3/28
Filed: 1956-03-12
Abstract: 829,906. Copy-turning. FISCHER A.G., G. March 12, 1956 [March 12, 1955], No. 7695/56. Class 83 (3). In a method and machine for reproducing from at least one pattern in a copying-lathe, a tracer is mounted for universal movement on a compound slide-rest for movement therewith along two co-ordinates in a plane, the tracer displacements directly controlling movements of the tool parallel and perpendicular to the workaxis in a plane parallel to the first plane. In the form shown in Figs. 1 and 8, the tool 10 is carried by a slide 9, movable transversely to the work 1 by an hydraulic cylinder 11 and fixed piston 12, on a saddle 3 movable parallel to the work-axis by a cylinder 5 and fixed piston 4. Supply to the cylinders 5, 11 from a pump 23 and regulating-valve 25, is controlled by valves 19, 20, respectively, connected by flexible rods 21, 22 to the lower end of a universally-mounted tracer 15, supported at 16 on a bracket 14 attached to slide 9. A frame 36 is rotatably adjustable on bracket 14, and is clamped at 89 with two arms 39, 40 in either the full-line or chain-line positions of Fig. 1. Racks 41, 42 are slidable on the arms 39, 40 by pinions 49, 50 and are connected at 43, 44 to plates 67, 68 embracing the upper end of tracer 15. The pinions are rotated by clutches 51, 52 and flexible shafts 60, 61 from a gear-box 59 driven from the headstock 121 in synchronism therewith. To produce work as in Fig. 1, i.e. between centres, clutch 51 is engaged to cause rack 41 to deflect the tracer NW, and a solenoid 66a is energized to deflect the tracer SW, whereby valve 19 is moved to the right and valve 20 down, causing saddle 3 to move left and slide 9 to approach the work. When a feeler 70 at the top of the tracer contacts a fixed pattern 34, the tracer is deflected thereby to overcome solenoid 66a and stop the feed of slide 9, but continued motion of rack 41 maintains the saddle-feed parallel to the work-axis. The feeler 70 thus traverses along the pattern, the solenoid 66a maintaining a bias towards the pattern to follow the shape thereof. At the end of a cutting-traverse, solenoid 66a is de-energized and clutch 51 disengaged, and solenoids 66, 64 are energized to deflect the tracer NE, whereby the tool is withdrawn from the work and traversed rapidly to the right. During movement of frame 36 with the slide 9, rollers 37, 38 move along a fixed guideway 31 to displace the brackets 45, 46 carrying the pinions 49, 50 and maintain the motion of the racks 41, 42. The solenoids 66, 64 &c. and clutches 51, 52 may be controlled automatically. For traversing and biasing the tool in a different direction, the frame 36 is moved to the dotted position of Fig. 1, the rollers 37, 38 remaining in the fixed guide 31. In'a modification (Fig. 2, not shown), the solenoids 66 &c. are replaced by fluid-pressure cylinders and the actuation of clutches 51, 52 is electrically-interlocked with the adjusted position of frame 36. This method of operation may be used with " face-plate " copying. In another modification, a fixed circular frame 91, Fig. 3, has guides 102, 104 for the ends of bars 95, 105, the upper end of the tracer 15, universally mounted at a mid-point on the toolslide 9, passing through the intersection of the bars and being engaged by pins thereon. The bars are connected respectively by chains 109, 99 passing over sprockets 108, 98 driven through clutches 52, 51 and flexible shafts 60, 61 from the gear-box 59 driven synchronously with the headstock-spindle. To traverse the tool 10 and feeler 70 along the work 1 and pattern 34, clutch 51 is engaged to cause bars 105 to move to the left and displace the tracer to cause saddle 3 to be fed left. A motor 111 is also energized to rotate sprockets 108 and cause bars 95 to move towards the work, thus feeding the feeler and too] inwardly until the feeler engages the pattern, whereupon the motor 111 stalls but maintains the feeler in contact with the pattern during the traverse. At the end of the traverse the clutch 51 is disengaged and the motor 111 reversed to withdraw the tool. In a further modification the saddle 3, Fig. 5, is traversed by an hydraulic motor 143 thereon, driving a pinion 144 engaging a fixed rack 145. A slide 126 is movable on a fixed longitudinal guide 125 by a chain 130 passing over a sprocket 128 driven, through a gear-box 59, from the headstock 121. A frame 132, rotatably-adjustable on slide 126, carries inclined bars 135 engaging the tracer 17, and also carries a cylinder 139 movable on a piston 137 fixed to the frame, the cylinder being attached to bars 142 perpendicular to bars 135 and engaging the tracer. For a copying-traverse along the fixed pattern 34, the chain 130 is driven to move slide 126 to the left and displace the tracer through the bars 135, thus admitting fluid from the valve 19 to motor 143 to traverse the saddle to the left. Simultaneously fluid is admitted by control-means (not shown) to the cylinder 139 to displace bars 142 and admit fluid from valve 20 to the piston 12 to feed the tool-slide 9 towards the work and maintain the feeler in contact with the pattern during the traverse. In all the machines described above the traverse of saddle 3, retraction of tool-slide 9 and return of saddle 3 may be controlled by limit-switches &c. Boring.-For copy-boring work 115, Fig. 7a, in both directions of saddle-traverse, the saddle 3 is traversed to the left, as described above, to cause tool 117 to follow the shape 117a. For the return traverse, the drive 59 for slide 126 is reversed and fluid admitted to the lower end of cylinder 139, whereby the saddle is traversed to the right and the feeler is fed against a second pattern, of opposite hand to pattern 34, to cause a tool 118 to follow the shape 118a, having shoulders which could not be formed by tool 117.