GB210838A - A new or improved jig for boring main bearing units in position in crank case - Google Patents

Abstract

210,838. Beenham, W. C. A., and Halliday, G. S. Nov. 3, 1922. Boring-bar machines; boring-bars. - A jig for facilitating the boring of bearings, particularly in motor-car engine crank-cases, comprises a frame carrying a boring-bar, the supporting means for the bar being capable of adjustment so as to be set in line with the centres of the bearings by means of a removable setting bar. A self-acting or hand ieed for the boring-bar is provided. The frame comprises side members a, a<1>, secured to the crank-case by bolts j<8> and spaced apart by cross-members w which may carry steadies for the boring-bar k. At each end of the frame are U- shaped brackets b providing recesses in which bearing blocks are vertically adjustable by means of set-screws f. The bearing blocks carry the trunnions e<2> of circular bearings e, e<1>, which are also adjustable laterally and are locked in position by bolts g which grip the trunnions between a shaped head g<1> and the shaped end of a sleeve h. Removable flanged bushes h<8> for supporting the boring-bar are secured to the bearings by screwed studs h<7>, the bush in bearing e having the feed mechanism mounted on its flange. The feed mechanism comprises a stationary tube r<2> carrying a screwed sleeve s<2> which coacts with a spindle s<3> located to the boring-bar by a nut s', the sleeve having a series of equally-spaced notches on its periphery which may be engaged by a pivoted trigger on the tube. A wooden disc s<13> provides for rotating the sleeve when disengaged from the tube and a handle s<5> is provided on the spindle s<3>. The boring-bar is rotated by a star-shaped wheel, which, according to the Provisional Specification, is secured by a plain-ended screw in the bar entering a recess in the boss of the wheel, and a thumb screw. To set the jig, the crank-case bearings p, the boring-bar and bushes h<8> are removed and a tubular tool c, Fig. 3, is inserted in the bearings e, e<1> through openings provided for this purpose. The bushes h<8> are then passed over the ends of the tool and the bearings are set in the required position, after which the tool is replaced by the boring-bar and feed mechanism. A steady which may be mounted on the cross-members w comprises spring-pressed plungers x<5>, Fig. 7, carried in bushes x secured into the members w<2>, w<3> and set-screws x<11> which act on plugs shaped to fit the plungers for locking the latter in any position. The upper cross-member is slotted at y to provide for swinging aside to allow insertion of the boring- bar. According to the Provisional Specification, the bearings e, e<1> are rectangular, and the plungers of the steady are retained in the retracted position by means of pins operating in curved slots.