Spring devices – Vehicle – Comprising compressible fluid
Patent
1999-01-28
2000-11-28
Mar, Michael
Spring devices
Vehicle
Comprising compressible fluid
267 6411, 267218, 188276, 188297, 1882991, F16F 914
Patent
active
061524328
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a gas spring connected to a closure member for an opening, the closure member being movable in a first direction from a closed position to an open position and being movable in a second direction from the open position to the closed position, the closure member moving against gravity in one said direction, the spring comprising a hollow cylinder, a piston slidable within the hollow cylinder and connected go a piston rod sealingly and slidingly extending from the cylinder, the piston dividing the hollow cylinder into a first chamber between the piston and one end of the cylinder and a second main chamber through Which the piston rod extends, the first and second main chambers containing gas under pressure which tends to displace the piston rod from the cylinder, the gas spring being connected to the closure member so that such displacement of the piston rod tends to move the closure member in the said one direction, and externally controllable fluid pressure producing means for controllably augmenting the pressure of the gas.
Such a gas spring is known from EP-A-0 379 864. In this known arrangement, an external source of gas is connected directly to the first main chamber in the cylinder to vary the pressure for temperature compensation purposes. In the event of failure of the external pressure source, there could be a complete loss of pressure within this main chamber. The invention aims to deal with this problem.
In accordance with the invention, therefore, the known gas spring is characterised in that she piston rod is hollow, and by a second piston sealingly slidable within the hollow interior of the piston rod and dividing the interior of the piston rod into first piston rod chamber in communication with the second main chamber and a second piston rod chamber, and in that the externally controllable fluid pressure producing means applies externally controllable fluid pressure to and within the second piston rod chamber for moving the second piston within the hollow interior of the piston rod so as to augment the gas pressure within the first piston rod chamber and the first and second main chambers.
Fluid pressure springs embodying the invention, and for use in motor vehicles, will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:
FIG. 1 is a schematic diagram of part of a motor vehicle body, with a hatchback door whose opening and/or closing movement is controlled and assisted by one of the springs;
FIG. 2 is a cross-section through one or the springs;
FIG. 3 is a schematic diagram of one form of a hydraulic fluid system for use with the gas spring of FIG. 2; and
FIG. 4 is a schematic diagram of another hydraulic fluid system for use with the gas spring of FIG. 2.
The fluid pressure springs to be described in more detail below incorporate gas under pressure, the pressure of the gas being controllable by hydraulic means.
Referring to FIG. 1, a motor vehicle of which part is indicated diagrammatically at 5 has a horizontally pivotted hatchback door which is shown in the raised or open position. In a manner to be explained, the opening and/or closing movement of the hatchback door 6 is controlled and assisted by a fluid spring 8. The spring (to be described in more detail below) comprises a hollow cylindrical body 10 having a closed end which is connected to the hatchback door 6 by a pivotal joint 12. A piston rod 14 is sealingly slidable into and out of the opposite end of the cylinder 10 and its distal end is connected by a second pivotal joint 16 to the vehicle body 5.
The position of the fluid pressure spring 8 when the hatchback door 6 is closed is shown dotted at 8A in FIG. 1, the hollow piston rod 14 now being partially retracted within the cylindrical body 10.
The interior of the cylindrical body 10 contains gas under pressure. In the manner to be explained in more detail below, the pressure of the gas can be controllably altered by a hydraulic fluid arrangement. A source of adjustable hydraulic fluid pressure is
REFERENCES:
patent: 2564790 (1951-08-01), Orloff et al.
patent: 4428567 (1984-01-01), Fournales
Draftex Industries Limited
Mar Michael
Williams Thomas
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