GB866665A - An improved shaft seal - Google Patents

Abstract

866,665. Stuffing-boxes. SKINNER, R. L. Jan. 18, 1960 [Feb. 5, 1959; Aug. 17, 1959], No. 1782/60. Class 122 (5). A shaft seal comprises an annular housing 26, a sealing ring 34 having a sloping outer surface 42 and an inner face 36 adapted to engage the shaft, a garter spring 46 which encircles the sealing ring and urges it both radially inwardly and axially, and two support surfaces 30, 48 slidably supporting the sealing ring and garter spring respectively. The ring 34, which is of a material having good sliding properties such as nylon or preferably polytetrafluoroethylene, is formed with a radial shoulder 40 that abuts the flange 30 of the housing and a reduced diameter portion 38 which enters with clearance through an aperture 32 in the flange 30. The garter spring 46 is located by the support surface 48 which is a washer retained by a flange 50, and that part of the spring engaging the surface 48 may be ground flat. The seal is shown applied to the valve stem 16 of an internal combustion engine. In the free condition of the seal, Fig. 3, the spring 46 exerts substantially no force on the ring 34. When the seal is seated in its operative position as in Fig. 2, the spring urges the face 36 and an annular lip 44 into contact with the stem 16 and presses the ring against the bottom of a counterbore 24 in the valve guide 12. In a modification the washer 48 is replaced by an integral flange on the housing 26 forming an acute angle with the cylindrical wall 28. In a further modification, Fig. 7, for use on existing engines, the seal 138 and spring 46 are mounted in a cup-shaped housing 128 sealed to the valve .guide 12 by a rubber or the like washer 150 compressed by a spring 152 acting between the housing 128 and a retainer cup 155.