A new or improved jig for boring main bearing units in position in crank case

摘要

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, a1, secured to the crank-case by bolts j8 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 e2 of circular bearings e, e1, which are also adjustable laterally and are locked in position by bolts g which grip the trunnions between a shaped head g1 and the shaped end of a sleeve h. Removable flanged bushes h8 for supporting the boring-bar are secured to the bearings by screwed studs h7, the bush in bearing e having the feed mechanism mounted on its flange. The feed mechanism comprises a stationary tube r2 carrying a screwed sleeve s2 which coacts with a spindle s3 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 s13 provides for rotating the sleeve when disengaged from the tube and a handle s5 is provided on the spindle s3. 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 h8 are removed and a tubular tool c, Fig. 3, is inserted in the bearings e, e1 through openings provided for this purpose. The bushes h8 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 x5, Fig. 7, carried in bushes x secured into the members w2, w3 and set-screws x11 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, e1 are rectangular, and the plungers of the steady are retained in the retracted position by means of pins operating in curved slots.