Patent GB-600479-A (GB)
Title: Improvements in profile milling machines
IPC: B23C3/00
Filed: 1945-05-16
Abstract: 600,479. Copying by milling ; cutters. JONES & LAMSON MACHINE CO. May 16, 1945, No. 12362. Convention date, April 22, 1944. [Class 83 (iii)] In a rotating-work milling machine wherein the relative motion of the cutter and work transversely of the work axis is produced by a master cam rotated in synchronism with the work, a number of cams are provided, each corresponding to the contour of the work at a different point along its axis and the tracer and cutter are indexable along the work to bring them into register with the cams in succession. The machine comprises a bed 10 and drip pan 11 carrying a headstock 13 in which the work spindle 18 is rotated by a direct current variable speed electric motor 14, a belt drive 15 and a clutch controlled by a hand lever 28. The work, such as a cylinder forging 34 which is to have cooling fins cut therein, is located angularly and longitudinally on the spindle 18 by means of a fixture 17 and is maintained on the fixture by a tailstock spindle 32 actuated by a hand wheel 35 and locked by a hand lever 36. Gearing in a casing 19 on the headstock drives the cam-shaft 23 from the spindle 18 at the same speed, the camshaft being mounted in stationary bearings in a sleeve 25 and carrying a series of cams 24. The cutter 57, Figs. 5 and 6, which may consist of a single saw or a number of saws each adapted to cut a cooling fin to the same depth and contour, is carried by a spindle 56 mounted in bearings 54, 55 in a bracket 53 which is fixed on a bar 40 capable of sliding and oscillating in pedestals 41, 42 on the bed 10. An alternating current electric motor 51 for driving the cutter is mounted on the bracket 53 and a second bracket 60, carrying the tracer roller 77, is angularly adjustable on bracket 53 by bolts 64 and an intervening lug 67. The tracer is carried by a spindle mounted in ball and roller bearings and secured against axial motion in the bracket 60. Oscillations are imparted to the bar 40, to bring the cutter and tracer into and out of engagement with the work and cams 24 respectively, by means of an arm 46 splined to the bar and rocked by a hydraulic cylinder 48, the pressure in the cylinder also serving to maintain the tracer in contact with the cam. Axial indexing movements are imparted to the bar 40 and bracket 53 by means of a lever 92 pivoted at 91 and connected at 94 to a hydraulic cylinder 96 which is pivoted at 97 to a bracket 90. This bracket is adjustable axially on the bed 10 by a screw and hand wheel 98 to position the tracer 77 opposite to the end cam 24, an adjustable stop 133 on the bar then being in contact with the first of a series of stops 102 on an indexable member 101. The member 101 is carried by a shaft 112 journalled on the bracket 90 and is indexed by a plunger 120 actuated by a hydraulic cylinder 118 on the bracket. A spring-pressed dog 125, Fig. 10, pivoted at 123 to the plunger 120, engages one of a series of pins 122 on shaft 112 during movement of the plunger towards the headstock 13 to rotate the member 101 and bring the next stop 102 in line with stop 133. At the same time a ramp 139 on the plunger rocks a lever 134, pivoted at 135, to cause a locking bolt 131 to be removed from an index notch 132 in the member 101, and on return movement of the plunger 120 the latch 125 and a latch 138 on the lever 134 yield to allow the bolt 131 to lock the member 101 in its indexed position. A constantly acting spring-loaded brake 116, Fig. 2, prevents overrunning of the member 101 during indexing. In operation, with a hydraulic pump 152 for supplying the cylinders 48, 96, 118 being driven by an alternating current electric motor 151, a push-button is depressed to start the spindle motor 14 at a fast speed. A drum 29, rotated by the spindle 18 at half its speed, carries a series of dogs for operating switches 300, one of which is now actuated to open a solenoid-controlled valve and admit fiuid to cylinder 48 to feed the cutter towards the work, a switch being actuated by the bracket 60 during its swinging movement to start the cutter motor 51. The cutter is fed to its full depth of cut, as limited by the cam 24, during the first 60 degrees of rotation of the work and a dog on drum 29 then actuates a switch to cause motor 14 to drive the work at a cutting speed of about 1 r.p.m. Cutting continues in conformity with the cam profile for a further 360 degrees, whereupon a dog on drum 29 causes fast rotation of motor 14 to drive the work for 300 degrees whilst indexing of the cutter and tracer takes place. Sirnultaneously with speeding up of the motor 14 another dog on drum 29 actuates a switch to reverse the solenoid-operated valve for the cylinder 48 to withdraw the cutter and tracer from the work and pattern, the swinging of the bracket 60 opening the switch to stop the cutter motor 51. At the same time another dog on drum 29 actuates a switch to operate the valve for cylinder 96, whereby the bar 40 is moved axially towards the headstock against a stop, and a sequence valve is then operated by the rise in pressure to supply oil to cylinder 118 which moves the plunger 120 to index the member 101 and bring the second stop 102 in line with the bar 40. A limit switch on the plunger 120 then reverses the valve to return the plunger to its retracted position and to move the bar 40 until its stop 133 engages the second stop 102, in which position the tracer will be opposite the second cam 24 and one cycle of operations will be completed. The first dog on drum 29 then commences the second cycle by swinging the cutter and tracer towards the work for producing a second groove or series of grooves in the work to the shape of the second cam, and after the required number of cycles has been completed a dog on the bar 40 operates a limit switch, when it has been moved to its extreme position against the last stop 102b, to stop the spindle motor 14, deenergize all the valve-operating solenoids, and re-set the circuits ready for repeating the series of cycles on a new workpiece. The Specification describes in detail a hydraulic and an electric circuit for the automatic operation of the machine.