GB349197A - Improvements in or relating to grinding or abrading machines - Google Patents

Abstract

349,197. Grinding. CINCINNATI GRINDERS, Inc., 3058, South Street, Cincinnati, Ohio, U.S.A.-(Assignees of Einstein, S. ; Avon Building, Clinton Springs Avenue, and Booth, C. ; both in Cincinnati, Ohio, U.S.A.) March 18, 1930, No. 8708. Convention date, March 28, 1929. [Class 60.] Rollers and the like, treating; round holes, enlarging and trueing; gauges.-A grinding machine is provided with means, adapted by momentary contact with the grinding wheel to discontinue the feed when the work is reduced to the required size the action being independent of wear of the wheel. As applied to a cylindrical grinding machine, the machine consists of a base 15 having thereon a work-table 17 and, on ways 18, a carriage 19 for the grinding wheel 21 movable to and from the work 30 by a screw 22, which is rotated, through gearing 25, 26, 27, by a shaft 28 driven by a worm wheel 29 thereon adapted to be engaged by, or disengaged from a movable worm 33. The worm is mounted on a shaft 32, driven by an electric motor 31 and mounted in a swinging bracket 34, which is held in operative position by a cam 37 connected with an arm 36 and a lever 40 carrying a switch 39 ; on movement of the lever, the switch is closed to start the motor 31, and an electromagnet 35 holds the arm 36 in position to maintain the worm in operative position. A shunt circuit 41, 42 also is provided, which, when closed, de-energizes the magnet 35 and allows the worm to fall from engagement with the worm wheel 29. The carriage 19 is retracted after release of the worm by a weight 47 acting by a member 48 on a pulley 46 on the shaft 28. The grinding wheel 21 is reciprocated axially to a small extent to equalize wear, and, when the work is to size, contacts with a feeler 61 carried by one of the members of a forked lever 57 pivoted at 58 in a housing 56 having an adjusting screw 60 therein and carried by an arm 55 adjustable on a bracket 54 which is adjustable in a slideway on the machine headstock. The other fork of the lever 57 carries a contact 43, which, when the grinding wheel strikes the feeler 61, makes contact with a contact 44 to close the circuit of a magnet 45 to hold the lever 57 with those contacts closed, thus also completing the shunt circuit 41, 42 and allowing the worm 33 to drop ; the lever carries an adjustable weight 59 and a baffle is provided in the housing 56 to protect the contacts 43, 44 from cooling water. In a modification, as applied to internal grinding, the feeler is suspended in the lateral feeding path of the grinding wheel. In a further modification, the motor runs continuously and additional switches are provided, so that the lever 57 is held away from the grinding wheel until the mechanism is reset for grinding a new piece of work.