| 摘要 |
825,799. Maintaining height of road vehicle body; dashpots. GENERAL MOTORS CORPORATION. Sept. 4, 1957 [Sept. 27, 1956], No. 27908/57. Classes 108(2) and 108(3) Air suspension valve control mechanism comprises a member 20 adapted to be moved by relative movement between sprung and unsprung portions of the suspension (not shown) to which is resiliently connected a second member 31 which is engaged with valve means 26, 27, which are thus actuated to maintain a predetermined height between the sprung and unsprung portions, and a delay device connected to the member 31 to delay its movement at one rate of response from a neutral position and at a second faster rate upon return towards the neutral position. A housing 18 for the mechanism is rigid with the vehicle chassis frame (Fig. 1, not shown), and carries a resilient bushing 36 which provides an air-tight pivot for the journal 32 of a control arm 20, the outer end of which is connected by a link to the vehicle axle. The journal 32 is rigid with a cranked arm 38 which lies adjacent a similar cranked portion of a lever 31 pivotally mounted on an extension 42 of the journal 32. A torsion spring 40 has both its ends 43, 44, extended radially to engage respectively the upper and lower surfaces of both the cranked portions of the lever 31 and the arm 38. Movement of the arm 20 in either direction thus acts through the torsion spring 40 to deflect the lever 31. The hollow interior of the housing 18 is connected by a conduit 28 to a source of pneumatic pressure. The opening of the conduit 28 into the housing 18 is controlled by a tyre-type valve 26, the stem 33 of which bears against the lever 31. A valve 27 similar to the valve 26 is connected to the lever 31 in such a way as to control escape of air from the housing 18 to atmosphere. The interior of the housing 18 is connected directly to the interior of a reservoir formed in a chassis frame member and connecting two tandem - disposed pneumatic suspension springs. The outer end of the lever 31 is connected to a U-shaped spring member 73 which is adapted to apply inward pressure to a pair of plugs 71, 72, which bear respectively upon the diaphragms 60, 61, of a fluid dashpot. The outer peripheries of the diaphragms are held in engagement with an annular member 51 the inner surface of which forms a cylinder and which is divided into two chambers 53, 54, by a transverse wall 52. A restricted orifice between the chambers 53, 54, is formed by a bore 55 obturated by a pin 58, and connected by ports 56 and 57 with the chambers 53, 54. The plugs 71, 72 are formed with a frusto-conical cross-section and this has the effect together with the precompression of the dashpot liquid of resulting in a tendency for the plugs 71, 72 to centre themselves with respect to the cylinder 51. Alternatively the plugs 71, 72 may be cylindrical and surrounding sleeves 67, 68 may be conically flared. Specification 786,849 is referred to.
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