GB191117477A - Improvements in Lathes. - Google Patents

Abstract

17,477. Schellenbach, W. L., and Lodge & Shipley Machine Tool Co. Aug. 1. Lathes.-Engine lathes are provided with a multiple tool-holder with special tool-posts arranged to operate a selector stop-bar device for gauging the surfacing and traversing motions and for automatically stopping the power traversing gear. The slide-rest carries a series of tool-holders 10, Figs. 1 and 2, pivoted on removable trunnions to engage, when required, a common support F, Fig. 6, having a key I, with inclines i<3> and a screw-down action controlled by a handle and racks and pinions J. which engages a T-slotted recess h<2>, Fig. 3, in the base of the tool-posts, which have a swivelling upper portion G. Each tool-holder is recessed to contain a slide k<1> adapted to engage, when the tool-holder is in the operative position, with one of a series of pins K which stand in the path of surfacing stops 30 adjustably secured at 29. The slides k<1> are shouldered at k<5> and the pins K at k<8>, to provide for roughing and finishing cuts. The slides k<1> can be slid out of the paths of the pins K if the stops are to be dispensed with temporarily. The saddle is traversed from a spindle shaft by bevel and spur gearing, partly shown in Fig. 2, and including a hand crank and a friction clutch M<1>. The train terminates in a pinion engaging the rack d<2>. A second rack O adjustably secured to the bed engages a pinion P journaled in the saddle and meshing with a pinion splined to a cam-shaft Q which is carried by the slide-rest, and carries a number of axially and angularly adjustable stop cams R, one for each tool-holder. A rock-shaft S, Fig. 14, carries pivoted arms 40, with screws 46 preferably having stepped heads to provide for roughing and finishing cuts, and rocked into and out of operative position by levers 50 controlled by the pins K. The shaft Q has a screwed connexion with the slide-rest q, to permit the cams R to make one or more revolutions before contacting with the stop-bars to enable the diameter of the cams to be kept small without restricting the saddle travel. When a cam contacts with a stop, the shaft S is rocked, and, through a series of rods and levers, slides the sleeve m<2> to disengage the clutch M<1>. The feed is then continued by the hand crank till the end of the lever 40 in action is brought against the dead stop 48, Fig. 14. In a modification, the tool - posts are detachable instead of being pivoted, and have fixed tail-pieces with slides similar to the slides k<1> adapted to engage each with a particular one of the pins K. When turning a number of similar articles from stock w, a centre rest T is employed, and, at the beginning of the operation, the graduated rack-bar O is set with the stop O<2> in contact with the saddle. After the finished article has been parted, the bar O is unclamped from the bed and shifted along until the stop again contacts with the saddle.