GB705099A - Improvements in and relating to seals for rotary shafts and the like - Google Patents

Abstract

705,099. Stuffing-box substitutes. SELFCHANGING GEARS, Ltd. Sept. 17, 1952 [Sept. 28, 1951], No. 22718/51. Class 122 (5) A rotary shaft oil seal comprises a circumferential helical groove or like formation arranged on one or both of a pair of closely spaced relatively rotatable surfaces to return oil in the direction of leakage, in combination with two engaged faces in rubbing sealing contact which faces are separated by centrifugal means when the shaft rotates at and above a predetermined speed. A rotary sleeve 1. closely surrounded by a stationary sleeve 3 having a helical groove 4 on its inner peripheral surface, is mounted on a flexible metal disc 7 and urged thereby into rubbing sealing contact with an inturned flange 6 of the sleeve 3. The disc 7 is gripped between two rings 9, 10 on a bearing shaft 2 and the outer ring 10 has a recess 11 therein housing balls 12 and having an inwardly tapered or curved wall 14 which, when the balls are thrown outwardly by centrifugal force deflects them axially into contact with the disc 7 and, at a predetermined speed, the rubbing faces of the sleeves 1 and 3 are separated. At and above that speed sealing is effected by the helical groove 4. In a modification the disc 7 is loaded by a plate spring and the balls 12 are mounted in a recess in a ring, on the bearing side of the disc and arranged to engage an inclined annular surface on the rotary sleeve 1 to thereby withdraw it, at a predetermined speed, from rubbing contact with the stationary sleeve 3. In a further modification the balls 12 are replaced by weights attached to, or integral with, a slotted ring adjacent the disc 7, the weights being offset from the plane of the ring, so that under centrifugal force they bend the outer portions of the slotted ring and thereby axially displace the disc 7 and the sleeve 1.