Brakes – Internal-resistance motion retarder – Resistance alters relative to direction of thrust member
Reexamination Certificate
1998-12-18
2001-07-24
Oberleitner, Robert J. (Department: 3613)
Brakes
Internal-resistance motion retarder
Resistance alters relative to direction of thrust member
C188S282500, C188S282600
Reexamination Certificate
active
06264015
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a continuously variable single-tube shock absorber with bidirectional control valves, comprising:
a working cylinder,
a piston which is connected to a piston rod and is movable in the working cylinder,
openings cut out in the piston,
spring-loaded shock absorber valves fitted on either side of the piston, in order to shut off said openings until a certain fluid pressure has been reached.
The object is to provide such a shock absorber operating according to the skyhook principle, in the case of which the body of a car equipped with such shock absorbers is virtually unaffected by the road aid, as it were, hangs from an imaginary fixed point above the road. Another object is to design the shock absorber in such a way that a proportional continuous adjustment is possible and that—unlike the shock absorber disclosed in EP-A-0268608—it is not limited to only two positions in both directions: hard and soft damping.
Yet another object is that the initial stressing force for the shock absorber valves can be applied uniformly over the entire periphery.
SUMMARY OF THE INVENTION
To this end, according to the invention, the single-tube shock absorber is characterized in that an exciting chamber, bounded by a stationary disc, a piston skirt which can be slid around such a disc, and two spring-loaded plates, is situated on either side of the piston, in that said exciting chambers are in communication with a bore in which the pressure is controlled by a control mechanism, and in that bores by way of which fluid can flow into the exciting chambers are provided in said stationary discs.
It is preferable for each set of spring-loaded plates to be clamped near the piston rod and for the shock absorber valve to rest with initial stress against an edge of a piston skirt.
In order to avoid undesirable leaks in the exciting chambers, each exciting chamber can be divided into two parts by two spring-loaded plates, which spring-loaded plates grip with their outside edge around a radial edge of a piston skirt and at their inside edge are clamped near the piston rod, while of the said two spaces the space facing the shock absorber valve is connected by way of a narrow radial passage to the space surrounded by the cylinder.
If no excess pressure is present in the exciting chambers, it is preferable for the piston skirts not to exert initial stressing forces on the shock absorber valves.
The control mechanism can be in various embodiments. For example, the mechanism can comprise a valve which is adjustable by a coil and which can continuously vary the pressure in the central bores in proportion to the electric current to be sent through the coil. The valve to be adjusted by a coil can be a piston valve of the type shown in
FIG. 2
of the international patent application PCT/NL95/00408. Another possibility is that the valve to be adjusted by a coil is a metal diaphragm. This embodiment is described per se in the abovementioned international patent application PCT/NL95/00408, in connection with FIG.
3
.
In view of the simplicity and the low price, it can be highly preferable for the control mechanism to comprise a movable mass which is fitted in a spring-loaded manner above the piston, and is linked to the piston rod and controls the passage of fluid to a bore which is in communication with the exciting chambers.
REFERENCES:
patent: 2431966 (1947-12-01), Rossman
patent: 4515252 (1985-05-01), Hidaka et al.
patent: 5690195 (1997-11-01), Kruckemeyer et al.
patent: 5823306 (1998-10-01), de Molina
patent: 553353 (1974-07-01), None
patent: 0499183 (1992-08-01), None
patent: 0572040 (1993-12-01), None
patent: 567367 (1945-02-01), None
patent: 2222227 (1990-02-01), None
patent: 8909891 (1989-10-01), None
Patent Abstracts of Japan, vol. 95, No. 012 & JP 07 332425A (Tokico Ltd), Dec. 22, 1995.
Patent Abstracts of Japan, vol. 015, No. 039 (M-1075), Jan. 30, 1991 & JP 02 278026A (Tokico Ltd) Nov. 14, 1990.
Bachman & LaPointe P.C.
Koni B. V.
Nguyen Xuan Lan
Oberleitner Robert J.
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