GB642531A - Grinding machine - Google Patents

Abstract

642,531. Grinding cams &c. NORTON CO. May 29, 1946, No. 16309. Convention date, July 16, 1945. [Class 60] A machine for grinding oval automatic cams, ovalshaped pistons or other articles comprises a rotatable grinding wheel, a pivotally mounted rock bar, a rotatable work support on said bar to support a cam being ground, a rotatable master cam on said rock bar in axial alignment with the cam to be ground, a follower roller arranged to engage the master cam, a pivotally mounted frame to support said roller, means to maintain said master cam in engagement with said roller, and a link the ends of which are respectively pivotally connected to said rock bar and said frame, the link being adjustable relatively to said rock bar and said frame to compensate for reduction in diameter of the grinding wheel or for determining the length of the minor axis in the finished article. The grinding wheel 20 is mounted on a slide 21 movable transversely on the machine base 10 by a screw 32 operated, through gearing, by a handwheel 29 having micrometer feed adjusting mechanism 30 as described in Specification 6784/01, [Class 60]; the grinding wheel is belt driven from an electric motor 24 carried by the slide 21. The work 42 is carried at one end in a work-holder 41 on a headstock spindle 40 carried by a rock bar 35; the other end of the work is supported by a centre 43 in a footstock 44 adjustably carried by the rock bar 35. The rock bar 35 rocks upon trunnion studs 36, 37 journalled in brackets 38, 39 carried by a work table 11 which is movable longitudinally on the machine base 10 by power or manually, as e.g. by rack 19 and pinion actuated by handwheel 15. The headstock spindle 40 is driven through a telescopic shaft 54 and universal joints 53, 55 from a shaft 51 mounted on the work table 11 and belt driven by an electric motor 46 mounted on the work table 11. A master cam 58 is supported on the headstock spindle 40 and cooperates with a roller 60 carried by a frame 62 pivoted at 63 to a bracket 64 mounted in a housing 45 secured to the work table 11. A tension spring 80 is connected at one end to a stud 81 adjustable in the housing 45 and at the other end to an arm 84 secured to the rock bar 35 so as to maintain the master cam and roller in contact. A link 70 is: connected between a pivot stud 71 on the frame 62 and a pivot stud 72 on the rock bar 35; the studs 71, 72 are adjustable relatively to the frame 62 and rock bar 35 respectively by screws 73, 74. It is stated that,. with a given grinding wheel and given master cam, such adjustment of stud 71 and/or stud 72 increases or decreases the length of the minor axis produced on the work, the major axis remaining unchanged. To maintain a desired shape of work despite reduction in size of the grinding wheel due to wear and/or trueing, compensation on the minor axis is effected as just described and compensation on the major axis is effected by feeding the grinding wheel closer to the work.