GB228303A - Portable boring-bar apparatus - Google Patents

Abstract

228,303. Barnes, J. W. Dec. 6, 1923. Boring-bar machines; boring-bars.-In a boring-bar machine, for boring the lignum-vitµ bushes of ships' propeller-shafts. of the kind in which the bar is journaled in a multiple-grip head adapted to centralize the bar in which a cutterhead is traversed along the bar by a feed-screw driven from the bar, the latter is hollow to accommodate the feed-screw which is driven by reducing gearing. The boring-bar 26 is attached by a flange to a head 12 mounted by roller or other bearings 38 in a casing 8 secured to the spider 1 having three adjustable jaws 4 for gripping a stern-tube nut. The head is rotated from an electric-motor 10 by worm gearing 11 and carries a gear-wheel 23, Fig. 4, which drives through reducing gearing 18, 15, a pinion on a spindle 13 connected by a clutch to .a feed-screw 27 extending through the bar and engaging a half-nut on the cutter-head 33, an arm carrying the nut extending through a slot in the bar and serving to drive the head. The gear-wheel 18 may be displaced axially to enable the feed-screw to be rotated by hand at 36. A roller centrenut 40, Fig. 3, having radially adjustable pins 41 supports one end of the bar in the stern-tube, and a diaphragm 37, Fig. 4, assists in supporting the boring-head and serves to retain lubricant. Jigs.-A light rod or tube 42, Fig. 3, attached to the bar by a long taper 43 serves to centre the bearing 40 either visually or by gauge.