Patent GB-925431-A (GB)
Title: Improvements in bore size control mechanism for use with a honing machine
IPC: B24B33/06
Filed: 1961-05-12
Abstract: 925,431. Linear-dimension gauges. MICROMATIC HONE CORPORATION. May 12, 1961 [May 18, 1960], No. 17474/61. Class 106 (2). [Also in Group XXIII] A bore size control mechanism for use with a honing machine having a rotating and reciproeating honing tool includes a gauging head adapted to be reciprocated in and out of a bore being honed in timed relation to the reciprocation of the honing tool, the gauging head having a pair of spaced surface portions adapted to engage the wall of the bore to be gauged at angularly spaced locations, means of the gauging head defining a fluid-emitting orifice disposed between the surface portions and arranged to direct fluid against the wall of the bore opposite thereto, a fluid pressure system arranged to deliver fluid to the orifice, a switch actuable for control of the bore size, and means for actuating the switch in response to fluid pressure developed in the fluid pressure system by the restriction to the escape of fluid from the orifice created by the reduction in distance between the orifice and the bore wall opposite thereto upon the enlargement of the bore to a predetermined size. A honing machine has a column 12 provided with a housing 14 supporting a ram 16 for vertical reciprocation. A drive spindle 18 supported within the ram 16 is connected to the drive shaft 22 of a honing tool 20. The honing stones 70 of the tool are moved radially by an axially movable feed rod 68. A platform 26 supports a fixture 28 positioning and holding the workpiece 30, the latter having a hardened liner 32, the bore of which is to be honed, positioned beneath a bore 34 of slightly greater diameter. A mounting plate 36 fastened to the top of the fixture 28 has a guide bushing 38 aligned with the liner 32 and serving to guide the tool into the workpiece. Guide-bars 40 pass through apertured housing ears 42, 44 and a gauge-mounting bracket 46 is supported between the lower ends of the bars 40. Adjustable collars 50 fastened to the bars 40 are positioned above a plate 48 fixed to the lower end of the ram 16. Downward movement of the bracket 46 and bars 40 is limited by adjustable collars 52 secured to the bars 40 and engageable with the housing ears 44, the collars being so set as to permit the gauging element to just enter the work bore. Downward travel of the bracket 46 is also limited by a guide pin 54 carried by the bracket 46 and adapted to enter a guide opening 58 of a bracket 60 secured to the mounting plate 36. The pin 54 abuts against an adjustable stop-screw 64. A gauge arm 66 is pivoted by a pin 80 on a block 72 fastened to the bracket 46. A spring 82 seated within the block 72 bears against the upper end of the arm 66, the tension of the spring 82 being controlled by adjustable setscrews 84. Movement of the arm 66 under the urge of the spring 82 is limited by an adjustable stop 87 in the block 72. At the lower end of the arm 66 is a gauge head 86 having hardened steel blocks 88, 90 whose outer faces are disposed on a common cylinder of a diameter corresponding to the diameter to which it is desired to hone the bore of the liner 32. A block 96 has in its outer face an orifice 98 communicating with a passage 102 extending the length of the arm 66 and communicating with a threaded inlet opening 104 fitted with a flexible air supply hose 106. The lower outer edge of the gauge head 86 is chamfered to facilitate the entry of the head into the liner 32 at each downward stroke of the tool. The blocks 88, 90 are urged into contact with the bore of the liner 32 by the spring 82. During upward movement of the gauge head 86, the orifice 98 is held away from the bore 34 by a rib 109 formed on the arm 66. Where the bore to be finished is immediately below the guide bushing, the rib 109 may be omitted and a slot machined in the guide bushing opposite the orifice; also the lost motion between the gauge and the tool may be eliminated by removing the stop screw 64, moving the collars 52 upwardly on the bars 40 and moving adjustable collars 53 upwardly on the bars 40 to engage the underside of the plate 48. Air from a supply conduit 114 passes through an adjustable pressure regulator 112, with a pressure gauge 112A, to an adjustable restriction 117 and thence to the hose 106, to a pressure-responsive diaphragm 118 and to a pressure gauge 121, which may be calibrated to display the dimensional variation of the bore from the final desired size. As the bore of the liner 32 is enlarged the back pressure of the air increases, and when the bore is of the desired size, the diaphragm 118 closes a switch 120. This energizes a relay R1 so (a) closing contacts R1a to establish a holding circuit, (b) closing contacts R1c to illuminate a bulb B, and (c) opening contacts R1b to de-energize a solenoid S, this permitting a valve 134 to spring return to a position in which hydraulic fluid is admitted to a cylinder 136 to retract a piston 138 connected to the feed rod 68 so as to collapse the honing tool. Additional contacts may be provided to effect automatic retraction of the tool from the workpiece or to perform any other desired function.