Patent GB-632429-A (GB)
Title: Improvements in or relating to a damping device
IPC: F16D35/00
Filed: 1946-05-29
Abstract: 632,429. Rotary hydraulic shock-absorbers. HOUDAILLE-HERSHEY CORPORATION. May 29, 1946, No. 16310. Convention date, May 31, 1945. [Class 108 (iii)] A viscous rotary damper comprises two sets of opposed parallel surfaces which are respectively oscillatable with a shaft and an enclosing liquid-tight housing, are interleaved, and are entirely free from any mechanical compulsion toward engagement of the respective sets but in operation are uniformly spaced to accommodate thin shear films of a viscous liquid, means being included whereby either or both sets is or are movable longitudinally of the shaft to assure proper spacing between the opposed working surfaces. In the construction shown in Fig. 17 an assembly of discs 116 is mounted in a cylindrical housing 105 between a plate 119 rigid with the housing backplate 104, and a plate 121. The discs 116 and plate 121 have peripheral tongues which engage slots 118 in the housing 105, in order to permit limited axial movement and restrain them rotationally. A second assembly of discs 115, in interleaving relation with the discs 116, are in splined engagement with a shaft 108. The latter is journalled at its inner end by an extension 111 of increased diameter in the end plate 104 and at its outer end in a roller bearing assembly 152 in a bush 151 coaxially mounted in a cover-plate 149 of the housing 105. A ring 158 bears on the plate 121 under the action of a coiled spring 159 which is in abutment with a ring 155 bearing on a shoulder 150 of the cover-plate 149. The loading of the spring and/or the spacing of the discs are varied by screwing the bush 151 axially relative to the cover-plate 149, in order to displace the ring 158 by engagement with an abutment 160 and by axial displacement of the ring 155 by screwing the cover-plate 149 inwards or outwards relative to the housing 105. In a modification (Figs. 11, 12, not shown), the spring 159 is dispensed with and the abutment 150 bears directly on the plate 121 to vary the spacing of the discs. In a further modification (Figs. 13-15, not shown), lost-motion is provided between the discs 116 and the housing by making the housing grooves 118 wider than the tongues which they engage. The width of the tongues may vary progressively so that the discs are loaded successively. In a further construction (Figs. 5, 6, not shown), in which lost motion is provided between the discs 116 and the housing 105, the spacing of both sets of discs 115, 116 is fixed in the axial direction. The discs 115 are secured on the shaft 108 by clamping nuts and spacer rings between the discs. The discs 116 are strung together as an assembly on four circumferentially-disposed clamping bolts which also carry annular spacing rings. The assembly has rotational movement relative to the housing limited by the engagement by the clamping bolts with respective pairs of rubber buffers mounted in peripheral recesses in the housing. In a further construction (Figs. 7, 8, not shown), in which the axial spacing of the discs is also fixed, the discs 116 are mounted by annular clamping rings within a tube which is co-axially disposed within, and rotatable relative to, the housing against the action of a coiled spring. The spring is disposed in an annular space between the tube and housing to which its ends are respectively connected. In a further construction (Figs. 9, 10, not shown) the discs 116 are positively secured in spaced relation to the housing between the back-plate and an annular abutment on the cover-plate, while the discs 115 are assembled on a tube which has a roller and ratchet one-way clutch connection with the shaft 108. The damping action may be variable for different relative rotational positions of the discs 115 and 116 as in Figs. 1-4 (not shown), by providing groups of holes in the disc surfaces. In a further construction, Fig. 16, the damping elements are of cylindrical shape. A cylindrical housing 136 has a bearing 137 for an operating shaft 138 which carries annular damping elements 140, 141 which co-operate with corresponding annular elements formed by the housing 136 and members 134, 142 welded thereto.