GB841486A - A machine for grinding helical gear teeth on work pieces - Google Patents

Abstract

841,486. Grinding helical gears. GEAR GRINDING CO. Ltd. April 30, 1958 [May 17 1957], No. 15712/57. Class 60. A machine for grinding helical gear teeth on workpieces comprises a reciprocatory workspindle, a notched disc on the work spindle, a first member angularly movable about the axis of the work spindle, means for oscillating the first member during reciprocatory movement of the work spindle, a second member angularly movable about the work spindle axis, an index pawl carried by the second member and adopted to engage the notched disc, a cylinder carried by one of the members and containing a piston connected to the other of the members, and means for admitting hydraulic pressure to the cylinder to impart relative oscillatory movement to the members to move the index pawl from one notch in the disc to the next. A grinding wheel 38 is carried by an arm 37 on a slide 39 vertically adjustable on a column 35 carried by a sector 36 mounted on the machine base 10 for angular adjustment about a vertical axis. Associated with the column is means 40 for dressing the grinding wheel. The work piece 16, on which internal helical gear teeth are to be ground, is clamped to an annular headstock 15 on a spindle 14 mounted on a slide 11. The slide 11 is reciprocated on the machine base 10 by a doubleacting piston and cylinder 12, 13, admission of hydraulic pressure to the cylinder being effected by switches or other means operated by the slide. A sleeve 18 mounted on the spindle 14 for rotation relative thereto is secured to a segment 24 connected by steel tapes 23 to a slide 22 mounted on guide ways on the slide 11 for movement transversely thereof. Rollers 21 on the underside of the slide 22 engage the opposite sides of a bar 20 carried by a graduated disc 19 mounted on the base for angular adjustment about a vertical axis, so that when the bar 20 is set at an inclination to the axis of the spindle 14, reciprocation of the slide 11 causes oscillatory movement of the spindle 14. The work spindle 14 carries a peripherally notched disc 17. An arm 25 angularly movable about the sleeve 18 carries a pivoted index pawl 26 engageable with a notch in the disc 17. A toothed segment 27 connected to the index pawl 26 meshes with a toothed segment 28 pivotally mounted on the arm 25 and connected to the piston rod of a piston 29 in a doubleacting cylinder 30 on a carrier 31 secured to the sleeve 18. An adjustable stop 34 on the pawl 26 co-operates with a stop on the arm 25. A slave pawl 32 is also pivotally mounted on the arm 25 about the same axis as the index pawl 26 and is urged by a spring 33 into engagement with a notch in the disc 17. The slide 11 dwells at the completion of each reverse stroke and actuates means (not shown) for directing hydraulic pressure to the left of the piston 29 so that index pawl 26 is disengaged from the notched disc. When disengaging movement of the pawl is arrested by the stop 34 the piston moves the arm 25 relative to the carrier 31. The slave pawl leaves its notch and rides over the disc until it enters the next notch. This entry actuates a switch 41 controlling a solenoid operated valve to direct hydraulic pressure to the right of the piston 29. This causes the index pawl 26 to be engaged with the notched disc, whereafter the arm 25 is returned to its original position relative to the carrier 31. In this position an electric circuit is completed to initiate the next reciprocation of the slide 11.