GB427181A - A new or improved device for boring and reboring cylinders - Google Patents

Abstract

427,181. Boring - bar machines. HARTRIDGE, L., The Queensway, Ponders End, Middlesex. Oct. 14, 1933, Nos. 28468/33 and 8357/34. [Class 83 (iii)] A portable machine for boring internalcombustion engine cylinders &c., comprises a vertical cutter spindle journalled in a pedestal having a lateral foot at the lower end for attachment to the cylinder block and a gear case at the upper end containing two coaxial gears driven at different speeds from an electric motor secured to the pedestal, one gear being splined to the spindle for rotation thereof and the other being formed as a nut engaging a screw threaded extension of the spindle for imparting axial feed thereto. The machine comprises a foot 3 slotted at 4 for attachment to an engine cylinder block &c., and having a cylindrical pedestal 2 carrying bearings 11 for the boring spindle 7 and attached by a screw joint to an extension 1 carrying a gear box 17. The bearing sleeves 10 are tapered at both ends and split so that they may be contracted to take up wear by means of screwed rings 12. An electric motor 6 is attached to the part 2 and drives a pinion 19 through a shaft 15 containing a disconnectible coupling 16. The pinion 19 drives a gear 21 meshing with a gear 20 splined at 22 to the spindle and a shaft 24 secured to the gear 21 is slotted to engage a pin 25 on the boss of a hand wheel 27. Dogs 28 on the boss engage recesses in a gear 29 loose on the shaft 24 and meshing with a gear 31 formed as a nut engaging the screwed extension 23 of the spindle, the gear ratio being such that the nut 31 is rotated slightly more slowly than the gear 30 to give axial feed to the spindle 7. On raising the hand wheel 27 against the action of a spring 45 it may be disconnected from the shaft 24 without disengagement from the gear 29 so that the nut 31 may be rotated by the hand wheel whilst the spindle is maintained stationary by the motor 6, thereby feeding the spindle rapidly downwards or upwards. After a boring operation has been completed, the foot 3 is released from the cylinder block and the machine moved so as to free the cutter 33 from the work, whereupon the spindle is withdrawn axially by rotating the nut 31 through the hand wheel 27. Chain and sprocket gears may be used in place of the spur gears 19, 20 &c. Boring - heads; jigs.-The boring-head 41 is attached to the spindle 7 by screws and is provided with a lateral recess to receive a prismatic tool-holder 43 adjusted by a screw 44. Setting members 9 are slidably mounted in radial openings in the spindle and are adjusted by a central cone 34 and an encircling spring 40. The cone 34 is adjusted axially by a rod 37 passing through the centre of the spindle and screwed at the upper end to engage a nut 36. The members 9 are expanded to engage the unbored walls of a cylinder to centre the apparatus until it has been clamped to the cylinder block by means of nuts and cams, after which they are removed out of contact with the cylinder. The first Provisional Specification states that the members 9 may consist of rollers. In a modified boring head, guiding members 57, Fig. 3, are mounted in radial recesses in a sleeve 64 rotatable through ball bearings 65 on the head 56 and are expanded by a cone 50 connected by a pin 58 to a central rod. The upper end of the rod is screwed to engage a nut 52, Fig. 2, recessed to receive a spring 61 and a block 54 abutting on the end of the spindle 7<1>. In operation, the nut 52 is rotated by hand to expand the guides 57 into contact with the unbored cylinder walls and locked by a cap nut 59. The spindle 7 is then withdrawn from the cylinder, whereupon the spring 61 moves the nut and rod 51 upwardly, within the limits imposed by a pin 62, to give a further slight expansion to the guides. The cutter 33 is then placed in the head and fed into the cylinder. When the inclined surfaces 57<1> on the guides 57 meet the bored edge of the cylinder the guides are forced inwards slightly to allow them to enter the work and exercise a uniform steadying pressure thereon whilst the boring is proceeding. The cone 50 rotates with the spindle 7 but the sleeve 64 and guides 57 normally remain stationary in the bore. The bevelled surfaces 571 of the guides prevent cuttings from entering between the guides and the work. Stop - motions.-A switch 48, Fig. 1, for the motor 6 has an arm 49 connected to a vertical rod (not shown), the upper end of which lies in the path of a nut and lock nut, (not shown) on the screwed spindle 23. The nut is adjusted on the spindle to depress the rod against a spring and stop the motor when the cutter has completed its stroke.