Spring devices – Vehicle – Comprising compressible fluid
Patent
1995-12-21
1997-08-05
Butler, Douglas C.
Spring devices
Vehicle
Comprising compressible fluid
188282, 18832215, 188317, 188269, 18832222, 188314, 213 43, 213223, 267116, 267139, 267 6426, B61G 1112, F16F 906
Patent
active
056534256
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Field of the Invention
This invention relates to energy absorbers of the kind which comprise a cylinder and a hollow plunger slidable in the cylinder, the plunger having its interior divided into a gas containing space and a liquid reservoir by a movable wall and being provided with means whereby the liquid reservoir communicates with a liquid compression chamber formed within the cylinder outside the plunger, liquid displaced from the compression chamber into the reservoir by lengthwise compression of the absorber acting on the movable wall to displace it and thereby cause compression of gas within the gas containing space such that lengthwise compression of the absorber is resisted by compressed gas within the gas containing space which also provides a recoil force, there being liquid damping means which provide further resistance to compression of the absorber and damp the recoil force under certain conditions of operation. Such an energy absorber shall be referred to as "an energy absorber of the kind referred to" throughout the remainder of this specification.
2. Description of the Background Art
DE-B-1109206 discloses the use in an energy absorber of the kind referred to of a spring-closed pressure relief valve which is operable to open against the spring loading to allow displacement of liquid from the compression chamber into the liquid reservoir through an orifice which serves as the liquid damping means, when the liquid pressure acting on the obturating member of the pressure relief valve to open it reaches a certain threshold pressure which is many times higher than gas pressure within the gas containing space. The spring loading of the obturator of the pressure relief valve is applied by a stack of spring washers and is substantial. Liquid pressure loading on that obturator is insignificant compared to the load exerted by that stack of spring washers. That is so also with the energy absorber of the kind referred to disclosed by DE-A-3613677 which also includes a spring closed valve which is opened by liquid pressure in the compression chamber to allow displacement of liquid from the compression chamber to the liquid reservoir. The damping characteristics of the latter energy absorber are determined by the level of prestressing of the springs.
In order to provide the desired velocity dependent characteristics, it has always been thought necessary for the liquid damping means to comprise an orifice arrangement of flow restricting dimensions, the effective area of which is varied with relative telescopic movement between the hollow plunger and the cylinder, the effective area diminishing as the energy absorber contracts and increasing as it extends.
GB-A-982641 and GB-A-1266596 disclose examples of "an energy absorber of the kind referred to" which forms part of a side buffer for use on railway vehicles to absorb shock loads transmitted from one vehicle to another during acceleration and deceleration of a train, or during wagon impacts in marshalling yards and which, in the conventional manner, incorporate a profiled pin which, with inward movement of the plunger, provides increasing restriction of an orifice through which the liquid reservoir communicates with the liquid compression chamber.
SUMMARY OF THE INVENTION
An object of this invention is to provide an energy absorber of the kind referred to which is less expensive to manufacture but which will have substantially the same `so-called` static and dynamic performance characteristics when used in a side buffer as an energy absorber which is similar to those disclosed by GB-A-982641 and GB-A-1266596.
Rather than using a variable area orifice arrangement of flow restricting dimensions as is conventional, by this invention we use a fixed area orifice of flow restricting dimensions as the liquid damping means of an energy absorber of the kind referred, in combination with a multiplier valve which cooperates with that orifice to multiply the resistance of the compressed gas within the gas containing space to lengthwise compressi
REFERENCES:
patent: 2366248 (1945-01-01), Focht
patent: 2788092 (1957-04-01), Whisler, Jr.
patent: 2886142 (1959-05-01), Orshansky, Jr.
patent: 2963175 (1960-12-01), Thornhill
patent: 3178166 (1965-04-01), Kirsch
patent: 3216535 (1965-11-01), Schultze
patent: 3251481 (1966-05-01), Karakashjan et al.
patent: 3389766 (1968-06-01), Henry-Biabond
patent: 3554387 (1971-01-01), Thornhill et al.
patent: 3656632 (1972-04-01), Karakashian et al.
patent: 3662649 (1972-05-01), Williams
patent: 3706326 (1972-12-01), Faure
patent: 3814219 (1974-06-01), Fannin et al.
patent: 3826343 (1974-07-01), Heymann
patent: 4054312 (1977-10-01), Strader, Jr.
patent: 4123859 (1978-11-01), DeKoning
patent: 4660687 (1987-04-01), Williams et al.
patent: 4850461 (1989-07-01), Rubel
patent: 5487480 (1996-01-01), Page et al.
Bushnell John J.
Page Ronald C.
Watts Carl F.
Butler Douglas C.
Oleo International Limited
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