GB415951A - Valve seat grinding tool - Google Patents

Abstract

415,951. Grinding valve seats. BLACK & DECKER MANUFACTURING CO., Towson, Maryland, U.S.A. Feb. 2, 1934, No. 3472. Convention date, May 5, 1933. [Class 60.] In a power-operated tool for grinding valve seats the spindle connecting the grinding wheel to the actuating means is vibrated in the direction of its axis, so as to lift the wheel from the work, at intervals which are indefinitely and variably timed in relation to the speed of rotation. In the tool shown, a portable hand tool 1 houses an electric motor 4 the shaft 6 of which is recessed at the end to receive telescopically the upper end 17 of a shaft 15, which it drives by a slot and tongue connection 14, 18. A spring 13 tends to force the shaft 15 downwardly, the thrust being taken by a pair of tapered cam rings 21, 22, between which are balls 24 or other antifriction devices. The cam rings are free to rotate on the shaft 15, so that the frictional effects produce irregular rotation of one with respect to the other, causing the desired irregular axial vibration of the shaft 15. Alternatively, either the ring 21 may be secured to the shaft 15, or the ring 22 may be secured to the casing, in each case the other ring being free to rotate. The shaft or sleeve 34 carrying the grinding wheel is connected to the shaft 15 by a universal joint formed by a cup 33 of hexagonal section in which engages a ball member 30 of similar section at the lower end of the shaft 15, the friction at this joint being sufficient to impart the axial vibratory movements of the shaft 15 to the sleeve 34. The sleeve 34 is provided with cooling fins 36, and it is steadied by a pilot spindle 27 secured in the valve guide.