Patent GB-667266-A (GB)
Title: Improvements in shock absorbing devices
IPC: F16F5/00
Filed: 1948-02-02
Abstract: 667,266. Hydraulic shock-absorbers. OLAER MARINE. Feb. 2, 1948 [Feb. 4, 1947], No. 3032/48. Class 108(iii). In a shock-absorbing device comprising a liquid pressure cylinder. and a piston slidable therein and having at least one rod, the rod is formed with two chambers, one containing liquid at substantially constant pressure, and the other communicating with the first chamber and with the cylinder spaces on both sides .of the piston so as to provide a liquid flow passage from side to side of the piston, a valve assembly comprising a valve member and a control element therefor and both capable of relative movement being arranged within the second chamber so as to be subjected to the variable liquid pressures in both cylinder spaces to normally close the passage by the valve member, the control element being furthermore subjected on one side to the substantially constant liquid pressure of the first chamber in such a manner that the valve member is allowed to open the passage under the action of either one of the variable liquid pressures only when the control element has been displaced by the same liquid pressure either against the substantially constant pressure or through the intermediary thereof. In the arrangement shown, in which a piston 10 is movable within a liquid-filled cylinder 1 by means of a two-part piston rod 9, 11, and in which a chamber 24 in the part 11 communicates with a chamber 25 in the part 9, the latter communicates with both sides of the piston 10 through ports 28, 29 and a valve member 34 which is normally located in the position shown in Fig. 1. A valve control element 30, 31, 32 is slidable within the member 34 and includes an extension 27 which provides a restriction 26 between the chambers 24 and 25. In operation, downward movement of piston 10 from the position shown in Fig. 1 effects displacement of the element 30 .. 32 and valve 34 to the position shown in Fig. 4 and during the return stroke, the valve 34 prevents flow of liquid through chamber 25 so long as the element 30 .. 32 remains stationary and until the resultant on the valve 34 of the pressures on either side of the piston 10, balances or overcomes the substantially constant pressure in chamber 24. Similar conditions apply when the piston 10 moves upwards from the position of Fig. 1, the sleeve 34, on the return stroke, closing the passage through chamber 25 so long as the element 30 .. 32 remains in the position shown in Fig. 3. Each end of the cylinder 1 is closed by a stuffing box comprising a packing 13 held between a scraper ring 12 and a cup shaped washer 14 by means of a ring 17 and spring 15. The Specification as open to inspection under Sect. 91 includes a shock absorber comprising a liquid-filled cylinder and a rod slidable therein and presenting two parts of different sections, Fig. 2 (Cancelled) (not shown). In a similar arrangement, Fig. 3 (Cancelled) (not shown), the cylinder filling consists of rubber or the like mixed with a viscous material such as mineral oil. The junction between the sections of the rod is of frusto-conical form. in a further arrangement, Fig. 4 (Cancelled,) (not shown), a baffle member is provided within the cylinder to restrict fluid flow therein and the sections of the rod are joined by a bulb-shaped portion. In another arrangement, Fig. 5 (Cancelled) (not shown), one part of the rod is slidable through one end of the cylinder and telescopes over the other part which is rigid with the other end of the cylinder. This subject-matter does not appear in the Specification as accepted.