Patent GB-737628-A (GB)
Title: Sizing mechanism for honing machines
IPC: B24B33/06
Filed: 1953-09-10
Abstract: 737,628. Linear-dimension gauges. BARNES DRILL CO. Sept. 10, 1953 [Dec. 11, 1952], No. 25091/53. Class 106 (2). [Also in Group XXIII] A machine for honing the bore of a workpiece 10 comprises a honing tool 13 carried on the lower end of a tubular spindle 14 projecting downwardly from and journalled on a head 15 guided along rods 16a mounted on a column 9 upstanding from the machine base; the parts of the spindle are coupled together by two hollow universal joints 17, 18. The spindle is driven by a motor 19 through speed-reducing gearing including a spline shaft 20. The hone is moved into the work and reciprocated therein by a hydraulic actuator 21. The honing stones are expanded and contracted by axial shifting of cams on the lower end of a rod 25 extending axially through the spindle 14, the rod being shifted up and down by a hydraulic actuator 26. A feeler 30 encircling the spindle 14 is mounted for reciprocation with the head 15 and for free transaxial floating so as to centre itself precisely in one end of the work-bore during part of each reciprocation of the hone and then enter the bore when the latter has been enlarged to the desired size, such further movement constituting a signal that the honing action should be terminated. The feeler comprises a cylindrical sleeve 31 carrying at its lower end a hardened ring 32 having an external cylindrical surface of diameter equal to the finished diameter of the bore; the lower end of the ring is tapered at 33. The sleeve is disposed within an opening 34 in a bracket 35 apertured at opposite ends to receive guide rods 16 mounted on the work support in front of and parallel to the main guide rods 16a. The upper end of the sleeve is smaller than a ring 36 fixed on the bracket, and a flange 37 on the sleeve is spaced from the wall of the opening 34. A spring 38 between the ring 36 and a washer 39 bearing against the flange 37 urges the sleeve downwardly, movement being limited by an inturned flange 41 on the bracket 35. The lateral floating of the sleeve is resisted by the friction resulting from the engagement of the flange 37 and washer 39 under the action of the spring 38. Thus the position of the sleeve 31, after it has been centred relative to the work-bore by the initial feeling engagement of the bevel 33 with the bore, will be held frictionally in this precise position relative to the bracket 35 when the sleeve is lifted out of contact with the work. By proper design of the spring and positioning of its abutments, the friction holding force may be adjusted to the magnitude desired for maintaining the positions of the gauge sleeve irrespective of the angle at which the honing spindle may be disposed in different machine installations. The bracket 35 has a -lost-motion connection with the reciprocating spindle head 15 formed by rods 42 upstanding from opposite ends of the bracket through apertures in projections 43 on the head 15; the rods 42 carry adjustable stops 44. Means is provided for engaging the hone when fully withdrawn from the work-bore and holding it approximately centred so as to ensure proper entry in the next bore to be honed, the means comprising two axially spaced guide surfaces 56 slightly larger and 56a smaller in diameter than the finished work-bore and positioned to receive and encircle the honing stones or the stones and the guides thereof as the hone is withdrawn from the bore. The surface 56 is formed on a ring 57 secured to a centrally apertured bracket 59 having bearings 60 at opposite ends slidable along the guide rods 16; stops 61 on the guide rods limit the downward movement of the bracket to a position in which the guide ring 57 is disposed close to the upper end of the work-bore. Rods 62 upstanding from the bracket 59 project slidably through the bracket 35 and carry nuts 63; thus the upward movement of the hone head 15 raises the guide ring 57 a short distance above the work-piece in the final withdrawal of the hone. The second guide surface 56a is formed on an inwardly turned flange 64 at the lower end of the gauge sleeve 31; the surface is sized to receive with ample clearance a hub 65 on the upper end of the hone body, the two parts being guided into telescoping relation by end bevels. When the work-bore is large enough to permit full entry of the ring 32, an arm 51, carried by the sleeve 31 and projecting through a slot 50 in the bracket 35, engages through adjustable screw 55 an actuating button 49 thus closing switch 46 and opening switch 48. The opening of switch 48 de-energizes solenoid 73 allowing valve 90 to reverse the flow of fluid to actuator 26 thereby collapsing the hone. The simultaneous closure of switch 46 completes a circuit through the then closed switch 103 to energize a relay 72 which closes a switch 101 and also a switch 100 for completing a holding circuit for the relay independently of the switch 46. The next upstroke of head 15 is initiated when lug 86 shifts cam arm 87 to rock lever 92 so reversing the valve 93. This also closes switch 102 thereby completing a circuit through the then closed switches 101, 103 for energizing solenoid 71 by which the position of valve 93 is maintained after the lug 94 shifts the cam arm 87. Thus the upstroke of the head is continued after opening of the feeler switch 46 thereby causing withdrawal of the head. At this time, the cam 76 depresses the follower 75 thereby opening switch 74 to de-energize relay 70 and therefore the relay 72 and solenoids 71 and 84. The cycle is thus interrupted with the parts in starting position. The control system is more fully described in Specification 601,526, [Group XXIII]. In a modification, Fig. 11, the bracket 35 and head 15 are connected together without lost motion, the rods 42 being threaded directly into projections 43 on the head. In a further modification, Fig. 12, the head 15 and bracket 35 are joined by a limited lost motion connection spring loaded in the expanding direction; the rods 42 carrying the stops 44 extend slidably through the projections on the head 15 and are urged downwardly by springs 105 acting in compression between the projections and collars 106 fixed to the rods.