Patent GB-1060981-A (GB)
Title: Improvements in or relating to internal grinding machines
IPC: B24B5/06
Filed: 1964-04-22
Abstract: 1,060,981. Grinding. ULVSUNDA VERKST€DER A.B. April 22, 1964 [April 24, 1963], No. 16637/64. Heading B3D. [Also in Division G1] An internal grinding machine comprises a chuck carrying a workpiece and a grinding wheel mounted on a spindle in a bracket, both said chuck and said grinding wheel being mounted so as to be rotatable and relatively displaceable axially as well as radially for grinding an internal face of the workpiece, a tool adapted to dress the grinding wheel at predetermined intervals, and a pneumatic measuring instrument provided with a gauge head having outlet nozzles for a pressure medium to be axially reciprocated in and out of the workpiece with a gap relative the internal face affecting the pressure of said pressure medium, the measuring instrument being disposed between said grinding wheel and said bracket with the gauge head partially embracing the spindle. A workpiece 16 is held by a chuck 14 rotatable in a headstock 12 secured to the machine frame 10. The grinding wheel 24 is mounted on a spindle 22 rotatable in a bracket 20 mounted on a cross-slide 26 fed transversely on a table 18 reciprocated longitudinally. A foot 30, secured to the table 18 between the grinding wheel 24 and the bracket 20, has an aperture for the passage of the grinding spindle 22 or a coupling (42) therefor and also has an annular groove receiving a flange 34 of a size gauge. The flange 34 comprises discs (44, 46) secured to the foot 30 by screws and terminating at their inner peripheries in part cylindrical portions (49, 50) forming a gauge head 36 fitting in the gap between the workpiece and the grinding spindle when the grinding wheel is in the workpiece. Air supplied to a passage 54 in the foot 30 passes through passages (62) formed between the portions (49, 50) prior to their assemblage to diametrically opposed nozzle apertures (64). Coolant is supplied to the grinding wheel through other passages in the gauge, the outlet (70) being located between the nozzles (64). Pressure air is supplied through duct 74, throttle 78 and duct 82 to the passage 54 and thence to the gauge; the pressure in duct 82 is communicated through valve 86 to a bellows 90. The valve 86 is normally closed but is opened, when the gauge head enters the workpiece, by an adjustable dog 96 on the table 18. Pressure air is also supplied through duct 76 and throttle 80 to an adjustable orifice 98; the pressure is communicated to a bellows 104. The bellows 90, 104 are separated by a wall 106 actuating an indicator 110, 112. When a desired value is reached a pin 114 closes contacts 116, 118 to interrupt the grinding operation. The grinding wheel is dressed by a diamond tip (122) adjustable by a screw (124) on a part 120 movable to operative position about a shaft (128) carried by a bracket (130) secured to the machine frame 10. For accurately positioning the diamond tip, an instrument 132 has a passage (134) with a nozzle (136) normally closed by a washer (138) biased by a spring (140). With the dressing tool in its inoperative position, pressure air is supplied to the passage (134) moving the washer (138) out into contact with the diamond tip (122). The pressure operates an indicator, and the diamond tip is adjusted accordingly. The adjustment may be automatic. In a modification, for grinding an injection nozzle for a diesel engine, the headstock 12 is movable transversely of the machine frame 10, while the grinding wheel bracket 20 is fixed transversely on the reciprocating table 18. The cylindrical bore of the workpiece is ground by the grinding wheel 24 and the tapered end (142) of the workpiece is ground by a grinding wheel (144) having an end taper, its spindle being journalled in a support (148) mounted on a slide (150) which can reciprocate in the direction of arrows (152) on the table 18. The foot 30 of the size gauge 32 is pivoted on a spindle (158) parallel to and below the grinding wheel spindle 22. The foot 30 is urged by a spring (162) against a stationary stop on the table 18. The spindle (158) is journalled in the bracket 20 by balls. (170) permitting axial movement against the action of yielding bellows (171). Movement of the spindle towards the headstock is limited by a washer (172). A stop (173) on the headstock is engaged by the spindle before the grinding wheel has reached its innermost position in the workpiece. In a first position of the headstock. the grinding wheel 24 grinds the cylindrical bore of the workpiece, the inoperative grinding wheel (144) being accommodated in a recess (154) in the headstock. An arm (166) attached to the gauge engages a member (168) on the headstock to centre the gauge relative to the workpiece. The headstock is fed transversely, carrying the gauge with it. In a second position of the headstock, the grinding wheel (144) grinds the tapered end (142) of the workpiece, the inoperative grinding wheel 24 being accommodated in a master ring (156) mounted in the headstock. The arm (166) engages a member (169) on the headstock to centre the gauge in the master ring (156), thus providing a check of the accuracy of the gauge. The bracket 20 may have a slot (174) extending over the greater part thereof and containing a plate (176) with a sealing ring (178). When compressed air is admitted through a passage (182) the bracket 20 is flexed about the uninterrupted portion (186) to retract the grinding wheel from the workpiece bore before withdrawing it from the bore.