Patent GB-772870-A (GB)
Title: Improvements in and relating to portable boring, reaming and honing machines for automobile cylinders
IPC: B23Q9/00
Filed: 1954-03-02
Abstract: 772,870. Portable boring-machines. GWILLIAM, V. C. E. MARTEN-. March 1, 1955 [March 2, 1954; June 21, 1954; Sept. 1, 1954], Nos. 6014/54, 18079/54 and 25330/54. Addition to 705,452. Class 83 (3). [Also in Group XXIII] A portable-machine for reboring, reaming and honing automobileengine-cylinders according to the parent Specification is modified by the provision of a screw-feed, for expanding the tool, operated automatically as the tool is rotated and reciprocated. The extremity of the mandrel 17 for expanding the tool is threaded into a feed-sleeve 16, Fig. 8, rotated intermittently by a wormwheel 26 coupled to the sleeve through a dog-clutch 27, a pin 29 in the sleeve engaging a slot in the top-element 28 of the clutch. A worm (not shown), engaging the wheel 26, is rotated by a ratchet 24, at each end of the worm, operated alternately by pawls 23 on a carrier 21 pivoted on the shank 5 of the tool, the wheels 24 being staggered in relation to each other by half the pitch of the teeth. The lever carries a roll 31 which follows a cam 32 as the tool-shank 5 reciprocates and rotates, the cam causing no movement of the carrier 21 except at the rise 34 at the end of the stroke of the tool. The rise 34 may cause the operative pawl 23 to turn its wheel 24 by an amount equal to half the pitch of its teeth, but can be made more effective by turning the cam 32 through a small angle, the carrier and pawls being influenced by springs into their operative positions. The top of the clutch is held down by a spring 30 engaging a nut for clamping the divided end 19 of the sleeve 16 after adjustment of a threaded stop-sleeve 20 to limit the expanded diameter of the tool. A stop-pin 35, insulated from the sleeve 20, completes the circuit from a car-battery, through a frame 36 reciprocating on a rod 37, to a lamp 40 when it contacts the mandrel screw 17. Alternatively, the lamp may be replaced by a plug connected to the solenoid of a combined circuitbreaker and starting-switch so that an electricmotor for driving the flexible-shaft 4 is stopped when the stop-pin 35 contacts the mandrel. A spring-toggle may hold the switch in the offposition and disconnect the solenoid to avoid running down the battery inadvertently. When the large end of the tapered mandrel is adjacent the threaded portion, the other end co-operates with a stop-pin 14, Fig. 4, adjusted by a threaded-sleeve and locked by a nut 13 and radial pins 12. The pin is insulated from the sleeve and completes a circuit to the lamp through an insulated-rod between the crankwebs of the engine being machined. As in the parent Specification, the tool may be rotated and reciprocated by a ball-headed pin 6, Fig. 1, engaging a socket 9 in the tool-shank 5. The pin is mounted in a worm-wheel 2 rotated by a worm 3 driven by the flexible-shaft 4 and is retractable to permit withdrawal of a boring- tool through the casing 33 of the machine, and the substitution of a honing-tool without disturbing the machine on the cylinder-block. A circlip 8, Fig. 2, retains the pin in position and is accessible, through a hole in the casing closed by a plug 10, for re-positioning in holes 11 to one side of the pin to permit withdrawal of the latter. In a modification suitable for honing, Fig. 11, the tool is rotated and reciprocated by bevel-gears 41, 47 and an eccentric pin in a ballbearing 45 running in a channel 44 in the toolshank. The eccentric and bearing 45 may be retracted clear of the tool after releasing a lockscrew 50 for the bearing bush 49 of the driveshaft 46, which may be rotated by hand. Wormteeth 51 are also formed on the bevel-gear 41 so that the latter may be driven at a slower speed for boring operations by a worm inserted in the casing. An inclined surface-plate may be provided on the machine for cylinder-blocks having inclined top-surfaces. The teeth of the blades in the tool may be produced by a single- or double-start, thread-milling operation with the blades mounted with radial rake in an arbor. Alternatively, the teeth need not be staggered in succeeding blades. Patterns generated by the teeth of the blades are depicted, and formulµ given for calculating tooth-pitch and the length of the tooth-flats. The blades may be held against the mandrel by coil, or leaf, springs.