Patent GB-1328901-A (GB)
Title: Expandible honing heads
IPC: B24B33/06
Filed: 1971-06-11
Abstract: 1328901 Honing SOC ANON AUTOMOBILES CITROEN 11 June 1971 [15 June 1970] 27403/71 Heading B3D [Also in Divisions F2 and G3] A honing head comprises at least two expandible honing members 22, 23, means 19, 20 for expanding them simultaneously, a resistive torque detector, Fig. 3, control means, Fig. 4, for actuating the expanding means in accordance with the detected torque, pneumatic means associated with at least one honing member 23 to indicate contact with a bore 28 being honed, and means, Fig. 4, responsive to said contact to increase the torque acting on the honing members 22, 23. Coaxial bores 27, 28 in a workpiece 29 may be honed simultaneously, the honing members 22, 23 comprising abrasive faced split collars, expanded by a frusto-conical member 19, engaging thrust members 15, 16 and actuated by a rod 20 of a double acting hydraulic ram 21. Control.-Ring 23 includes an air nozzle 30 connected through passages 32-35 and a line 40 to a sequence valve 41, pressure from a source 37 escaping through the nozzle only when the ring 23 is not in contact with the bore 28. The rings 22, 23 are supported by a tubular torsion member 2, attached adjacent its upper end, Fig. 1 (not shown), within a hollow rotary spindle 1, and a seal 8 on a lug 7 of the member 2, Fig. 3, normally engages the surface of radial slot 5 in the spindle 1 to close a nozzle 4, Fig. 4, therein. Compressed air from the source 37 is supplied to the nozzle 4 through a further line 39 to the valve 41 and a spindle passage 6, deflection of the member 2 under torsional engagement of either ring 22, 23 with the workpiece 29 causing the aperture 4 to be opened, thus venting the line 39 with a flow proportional to the torque applied. The sequence valve 41 includes respective capsules 44, 50 pressurized by the lines 39, 40, and spring means 45, Fig. 5, biasing the capsules towards collapsed condition. A bleed valve 63 in the hydraulic circuit 57 of the ram 21 is actuable from a source 51 through a line 48. A branch passage 49 passes through the valve 41, being open to atmosphere when the capsules 44, 50 are collapsed. On initiating a honing operation, with the rings 22, 23 out of contact with the workpiece 29 and the nozzle 4 closed, full pressure in the line 39 expands the capsule 44, thus closing the passage 49, expansion of the capsule 64 holding the bleed valve 63 open. Excess pressure in a ram chamber 56 thus actuates the ram 21, to expand the rings 22, 23 into honing contact, a flow regulator 62 governing the rate of expansion. Blocking of the nozzle 30 thereupon pressurizes the line 40, while spindle torsion opens the aperture, 4, causing collapse of the capsule 44. Venting of the line 48 thus causes the valve 63 to close, so that equalized pressure in the ram chambers 56, 58 halts the hone expansion, the balance of the pressures in the lines 39, 40 maintaining a constant honing torque. In an alternative construction, Fig. 6 (not shown), the nozzle 30 actuates a pressure contact switch (66) for electrically operating a valve (67) to pressurize the line 40. Further, both rings 22, 23, may be provided with respective nozzles 30, 30<SP>1</SP> for establishing respective constant torque levels according to whether one or both of the rings 22, 23 is in honing contact.