Patent GB-1004707-A (GB)
Title: Vibration damping shock absorbers
IPC: F16F9/06
Filed: 1962-11-20
Abstract: 1,004,707. Hydro-pneumatic shock-absorbers. BOGE G.m.b.H. Nov. 20, 1962 [Nov. 22, 1961], No. 43934/62. Heading F2S. A hydro-pneumatic shock-absorber comprising a housing 1 with a working cylinder 2 in which a valved piston 7 works and which contains oil 20 and a gas cushion 21 in an equalizing chamber 3 by which the oil is kept under pressure, and a separating body 13 located in the region of the separating surface 19 of the oil and gas is characterized in that the separating body 13 is in the form of a piston and leaves a narrow annular space 14 between itself and the internal wall of the housing 1. As shown in Fig. 1 the separating body 13 is urged by a spring 15 into its basic position cn to a stop projection 17 openings 18 in which provide communication between the equalizing chamber 3 and the cylinder 2. Air can pass through the annular space 14 during slow movements of the main piston 7 but during rapid movements of the piston oil 20 is mixed with gas 23 an oil film being continuously maintained in the space 14 to provide a seal so that only a small volume of gas below the separating body can mix with the oil. In a further modification, Fig. 2, not shown, the separating body which is provided with valves and openings is urged upward against stop projections by a spring which is constrained between the lower face of the separating member and a part of the main piston. In a further modification, Fig. 3, not shown, the separating body is held between two oppositely acting springs which act against a pair of transverse partitions provided with through openings. Fig. 4 shows a separating body 413 which is traversed by a piston rod 408 leaving a space 431, is urged by gravity on to a stop projection, and which has a valve 425. Gas at 423 can pass through the annular space 414 into the equalizing chamber 403, and oil 402a can reach the cylinder 402 through the valve 425. In an alternative arrangement the separating body, which consists of two telescopic parts urged apart by a spring, is urged downward towards a projection stop by a spring which is interposed between the separator body and the upper end of the cylinder and which is weaker than the spring within the separator body. In such an arrangement, Fig. 6, gas separation is effected through a passage 650 with an opening 627 into the equalizing chamber 603 which can be provided with a check valve 652. In the form of Fig. 7 pistons forming the separator are urged apart by a spring and are traversed by a piston rod 708. The cylindrical neck 740 of a pump chamber has an inward projection stop 741 for a lip on a tubular extension member 747 which carries the separator member 733, oil which can fill the pump chamber through an annular space around the piston rod 708, can be forced through a check valve 748 into the equalizing chamber 703. In another arrangement, Fig. 8, not shown, the equalizing chamber is positioned at an angle to a horizontally located working cylinder the separator body consisting of a plurality of pistons with springs and which co-operate with a stop member so that fluid is constantly pumped from the operating cylinder into the equalizing chamber and a complete removal of air from the working cylinder is achieved.