| 摘要 |
686,662. Hydraulic shock-absorbers. BOURCIER DE CARBON DE PREVINQUIERES, C. M. L. L. April 27, 1948 [May 31, 1947; July 2, 1947; Jan. 21, 1948; March 10, 1948], Nos. 11481/48, 11482/48, 11483/48 and 11484/48. Class 108 (iii). A direct - acting hydraulic shock - absorber comprises a piston spaced from the cylinder wall so that liquid flows between the outer surface of the piston and the cylinder wall in the form of a thin film the piston having means co-operating with the cylinder wall to centre it in the cylinder. The piston shown in Fig. 3 comprises a series of rigid or resilient washers 10 of less diameter than the cylinder bore, clamped on the piston rod between a pair of end plates 13 which are apertured at 14. The washers 10 may be radially slotted and may (as shown), or may not, Fig. o (not shown), be provided with spacers 12. The washers 10 may be replaced by a solid cylindrical portion occupying about the same axial length and of less diameter than the cylinder bore in order to provide a peripheral liquid-damping clearance. The central portion of reduced diameter may be of material which has a different thermal expansion coefficient from that of the cylinder in order to compensate for changes in viscosity due to temperature changes. The piston may be provided with two axial passages containing respective spring-loaded ball valves 6, 7 (Fig. 9), which relieve excess pressure on either side of the piston. The end plates may each be formed with an abutment of part-cylindrical profile. In the constructions shown in Fig. 9, the cylinder space above the piston includes a chamber 21 separated from the remainder of the space by a head 27. Flow into the space 21 is controlled by a spring-loaded ball valve 22, and flow in the reverse direction by a flap valve 25. Specification 686,723 is referred to. In the Specification as open to inspection under Sect. 91, the valve 25 of Fig. 9 may be rigid with the head 27 which has segmental portions removed which allow flexing of the valve. The bellows 29 may be replaced by a tubular dust shield rigid and concentric with the piston rod 1 and having drain holes at its bottom. This subject-matter does not appear in the Specification as accepted. |
