Patent GB-584310-A (GB)
Title: Improvements in and relating to tracer controlled copying and reproducing machine tools
IPC: B23Q35/12
Filed: 1944-02-24
Abstract: 584,310. Copying-lathes. NILES-BEMENT-POND CO. Feb. 24, 1944, No. 3474. Convention date, Sept 24, 1943. [Class 83 (iii)] [Also in Group XXXV] In a lathe or other copying-machine having an electric tracer following a fixed pattern, contacts operated by the tracer control two relays to effect the operation of magnetic clutches for an " in " and " out " feed and also a traversing feed which only operates when the others are stopped and a further relay operated by the tracer contacts delays the operation of the traversing feed until the " in " or " out " feed has been established. As applied to a lathe of the kind described in Specification 316,205, [Class 83 (iii)], the work is rotated by a headstock spindle 3 and the tool 19 is carried by a cross-slide 17 mounted on a saddle 6 traversable along the bed 1. The traversing motion is effected by a screw 7 and reversely operating magnetic clutches 10, whilst the cross-slide 17 is moved in or out by a screw 20 and reversely driven magnetic clutches rotated by an electric motor 24 mounted on the saddle. The clutches 12N, 12T, Fig 4, and 10E, 10W for the " in " and " out " feeds and for " east " and " west " traversing respectively are energized from the mains 86, 91 and are in the circuits shown controlled by relays X, Y connected to contacts 42, 43 and 50, 61 on the tracer 31. Each relay has three switches 70, 71, 72 and 74, 75, 76, the switches 70, 74 being in parallel and controlling the delay-action relay R. In operation, with the tracer 31 mounted on the cross-slide 17 out of contact with the stationary pattern 33, contacts 42, 43 energize relay X to close switches 70, 71 and open switch 72 thus energizing clutch 12N for " in feed and energizing relay R to open switch 84. When the tracer encounters the pattern, contacts 42, 43 are broken, de-energizing relay X and allowing a spring 73 to close switch 72 and open switches 70, 71. This de-energizes clutch 12N to stop " in " feed and de-energizes relay R to allow a spring 85 to close switch 84, thus energizing one of the clutches 10E, 10W through tracer contacts 50, 61 and switches 72, 76 to cause the saddle 6 to be traversed, the direction being determined by the manual setting of a switch 92. Closing of switch 84 provides an alternative circuit for the appropriate clutch 10E, 10W and thus makes the operation of this clutch momentarily independent of switches 72, 76. If the resultant traverse relieves the pressure of the tracer on the pattern, contacts 42, 43 will close again and relay X will be energized to re-start the " in " feed, but the traverse will continue momentarily due to the opening of switch 84 being delayed until relay R has been energized. If pressure of the tracer on the pattern is not relieved, however, a lever 39 in the tracer will be rocked to close contacts 51, 60, energizing relay Y which will start the " out " feed through switch 75 and clutch 12T. The traverse will again continue momentarily until switch 84 has been opened by energization of relay R, after which the " out '' feed will continue alone until diminished pressure on the tracer allows contacts 51, 60 to open. If the tracer contacts 42, 43 vibrate too rapidly to allow any of the clutches to be energized, the relay R, which is operated out of synchronism with relays X, Y, will allow switch 84 to remain closed for a sufficient time to cause the traverse to continue until the contacts 42, 43 are definitely closed or opened.