GB389376A - Improvements in and relating to machines for boring metal - Google Patents

Abstract

389,376. Boring-bar machines. STORM MANUFACTURING CO., Inc., 406, 6th Avenue South, Minneapolis, Minnesota, U.S.A. Aug. 11, 1932, No. 22508. Convention date, Jan. 20. [Class 83 (iii).] A boring-machine, particularly for re-boring engine cylinders, comprises a base for attachment to a cylinder block &c. and carrying bearings for the boring-bar and a vertical pillar on which a cross-head is slidable, the boring-bar being rotatably attached to the cross-head. The base 11 is clamped to a cylinder block 10 by a clamp 94 and has an upstanding portion 12 in which the bearings 22 for the boring-bar 18 are secured. A boring head 16 is attached to the bar 18 and has cutters 19 adjusted in diameter by rotation of a screwed stem 21 on a cone 21<1>, as described in Specification 391,000, the stem 21 being attached to a rotatable rod 24 within the bar 18. An electric motor 33 has a double pulley for giving a twospeed belt drive to a pulley 42 geared to a worm-shaft 46 which drives a worm wheel 48 splined on a keyway 53 on the boring-bar 18 and prevented from moving axially by the bearings 22. The worm is double-threaded and the gearing has a 2 : 1 reduction. The belt is tensioned by adjusting a projection 35 on the base 34 of the motor along an inclined bracket 36 on the base 11, by means of a screw 39 and locking screws 38, the bracket 36 being radial to the motor shaft 37. A gear wheel 54, integral with the worm wheel 48, meshes with an axially immovable pinion on a vertical shaft splined within a worm carried by the crosshead 66 and engaging a worm wheel 58, Fig. 4, loose on a shaft 59. Gears 75, 76 are attached to the wheel 58 and drive gears 78, 79 loose on a shaft 81 but capable of being selectively keyed thereto by a sliding key 82 so as to drive the shaft 81 at one of two speeds. The key 82 is manipulated by a knob 84 and is engageable with one of a number of circumferentially spaced key-ways in the gears 78, 79. Gears 77, 80 permanently connect the shaft 81 to the parallel shaft 59 carrying a pinion 60 engaging a rack 61 on the vertical pillar 62 which is stationarily secured to the base 11. The crosshead 66 slides on the pillar 62 by means of a sleeve 69 and rotatably supports the boring-bar 18 by means of a lug 70, Fig. 2, carrying a flanged bush 71 which is secured between a thrust bearing 73 and an adjustable sleeve 27 held on the bar 18 by a screw 29. Hand adjustment of the head 66 is effected by a wheel 86 carrying a pinion 88 engaging a gear 89 on the shaft 81. Jigs.-The rod 24 is rotated, for adjusting the diameter of the cutters 19, by means of a sleeve 25, Fig. 2, having a lower bevelled edge 90 divided into fifty graduations. A central spigot 26 on the sleeve 25 screws in the end of the extension 27 of the boring-bar 18 with a thread of the same pitch as the thread of the stem 21 and the lower edge of the sleeve co-operates with a vertical scale on the member 27, the conicity of the stem, the pitch of the screws and the size of the scale graduations being so chosen that a complete revolution of the sleeve 25 displaces it over one division of the scale and adjusts the cutters by fifty thousandths of an inch. A screw 31 and wedge block 30 enables the sleeve 25 to be adjustably clamped to the rod 24 for setting the scales. Operation.-The apparatus is lifted by an eye-bolt 105 and a hoist on to a cylinder block 10 and the boring-head 16 is lowered into the cylinder to be bored by rotating the shaft 59 by the hand-wheel 86. The cutters 19 are adjusted so as to lie along the previously determined maximum diameter of the cylinder and are moved into contact therewith by rotating the sleeve 25, thus centring the bar 18 in the cylinder and enabling the maximum diameter thereof to be read on the scales. The base 11 is then clamped to the cylinder block, the boring- bar withdrawn with the cutters collapsed, and the cutters reset to the maximum cylinder diameter or slightly over. The motor 33 is then started and the boring-bar is rotated and fed through the cylinder. Automatic stop-motions.-When the boring- head has passed completely through the cylinder, a collar 102 adjustably secured to the boring- bar 18 by a screw 103 engaging the spline 53 makes contact with a trip which opens a switch and stops the motor 33. Framing and supports.-The base 11 is provided with eight apertures 15, Fig. 2, around the boring-bar 18.