Brakes – Internal-resistance motion retarder – Relative speed of thrust member or fluid flow
Reexamination Certificate
1999-06-17
2001-04-17
Oberleitner, Robert J. (Department: 3613)
Brakes
Internal-resistance motion retarder
Relative speed of thrust member or fluid flow
C188S282600, C188S322170, C188S312000, C267S134000
Reexamination Certificate
active
06216831
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
The present invention relates to an improved frictionless hydraulic damper and frictionless hydraulic damper-snubber which will remain frictionless during extremely small vibrational movements.
By way of background, in U.S. Pat. Nos. 4,638,895 and 4,768,627 frictionless-hydraulic dampers and frictionless hydraulic damper-snubbers are disclosed. These devices worked well in a majority of applications in which they were used. As stated in these patents, the frictionless performance was due to the use of labyrinth seals or bushings which had a thin film of hydraulic fluid built up between the bushing and the shaft to eliminate metal-to-metal friction as the damper stroked. However, in situations where the vibrations to be damped are about 0.001 inches and smaller in amplitude, there was no thin film of fluid formed between the seal and the shaft so as to produce a hydrodynamic bearing, and thus the parts touched in metal-to-metal contact so that frictionless operation was not achieved. The structure of the present invention overcomes the foregoing deficiency.
BRIEF SUMMARY OF THE INVENTION
It is one object of the present invention to provide a frictionless damper and frictionless damper-snubber which is capable of damping vibrations of about 0.001 inches and smaller and still maintain its frictionless operation.
Another object of the present invention is to provide an improved hydraulic damper and damper-snubber in which frictionless operation is obtained at very small vibrational amplitudes in a highly efficient manner. Other objects and attendant advantages of the present invention will readily be perceived hereafter.
The present invention relates to a damper comprising a cylinder, first and second opposite end walls in said cylinder, first and second seals in said first and second end walls, respectively, an elongated shaft mounted for axial movement in said first and second seals, a piston head on said shaft located between said first and second end walls, first and second fluid-tight bellows mounted in sealed relationship between said shaft and said first and second end walls, respectively, fluid in said cylinder and in said first and second bellows, and first and second flexible washers mounted between said shaft and said first and second end walls, respectively.
The present invention also relates to a damper-snubber which has the structure of the preceding paragraph and wherein the piston head includes orifices therein and valves associated therewith to block said orifices when the piston head velocity exceeds a predetermined value.
The various aspects of the present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein:
REFERENCES:
patent: 4638895 (1987-01-01), Taylor et al.
patent: 4741516 (1988-05-01), Davis
patent: 4768627 (1988-09-01), Taylor
patent: 4815574 (1989-03-01), Taylor et al.
patent: 5487454 (1996-01-01), Klembczyk et al.
patent: 5727663 (1998-03-01), Taylor
Gastel Joseph P.
Kramer Devon
Oberleitner Robert J.
Tayco Developments, Inc.
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