Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
2002-01-09
2003-08-12
Schwartz, Chris (Department: 3683)
Land vehicles
Wheeled
Occupant propelled type
C188S275000
Reexamination Certificate
active
06604751
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to vehicle suspensions systems. More particularly, the present invention relates to acceleration sensitive damping arrangements suitable for use in vehicle dampeners (e.g., shock absorbers, struts, front forks).
2. Description of the Related Art
Inertia valves are utilized in vehicle shock absorbers in an attempt to sense instantaneous accelerations originating from a particular portion of the vehicle, or acting in a particular direction, and to alter the rate of damping accordingly. For example, the inertia valve may be configured to sense vertical accelerations originating at the sprung mass (e.g., the body of the vehicle) or at the unsprung mass (e.g., a wheel and associated linkage of the vehicle). Alternatively, the inertia valve may be configured to sense lateral accelerations of the vehicle.
Despite the apparent potential, and a long history of numerous attempts to utilize inertia valves in vehicle suspension, commercial inertia valve shock absorbers have enjoyed only limited success. Most attempted inertia valve shock absorbers have suffered from unresponsive or inconsistent operation due to undesired extraneous forces acting on the inertia valve. These extraneous forces may result from manufacturing limitations and/or external sources and often inhibit, or even prevent, operation of the inertia valve.
Further, there are currently no commercially available inertia valve shock absorbers for off-road bicycle, or mountain bike, applications. The problems associated with the use of inertia valves, mentioned above in relation to other vehicles, are magnified in the environment of lightweight vehicles and the relatively small size of mountain bike shock absorbers. Therefore, a need exists for an inertia valve shock absorber that can be commercially produced, and provides responsive, consistent performance without the problems associated with prior inertia valve designs.
SUMMARY OF THE INVENTION
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener includes an inertia valve, comprising an inertia mass. The inertia mass is movable between a first position and a second position. In the first position, the valve substantially prevents fluid flow through the first flow circuit and in the second position, the valve permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener also includes an inertia valve, comprising an inertia mass, and a stop defining a socket for receiving the inertia mass. The inertia mass is movable between a first position and a second position. When the inertia mass is in the first position, the valve is spaced from the stop. The valve is configured to substantially prevent fluid flow through the first circuit when the mass is in the first position. When the inertia mass is in the second position, the valve abuts the stop and is at least partially positioned within the socket. The valve is configured to permit fluid flow through the first flow circuit when the mass is in the second position. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener further includes an inertia valve comprising an inertia mass. The inertia mass is movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position, wherein duration of such delay is independent of direction of movement of the piston.
A preferred embodiment is a method of dampening. The method includes providing an acceleration-sensitive dampener having a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener also includes a second chamber. A first flow circuit connects the first chamber and the second chamber. The dampener further includes an inertia valve comprising an inertia mass. The inertia mass is movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The method additionally includes applying an acceleration force to the inertia valve to move the inertia mass from the first position to the second position and to move the piston within the first chamber. The movement of the piston continuing until the piston completes a compression stroke. The method further includes delaying the inertia mass from returning to the first position until after a period of time after completion of the compression stroke.
A preferred embodiment is a method of dampening including selecting an acceleration threshold at which lower dampening is desired. The method additionally includes selecting a time interval during which it is desirable to maintain the lower dampening and providing a dampener having an acceleration responsive valve movable between a closed position and an open position. In the closed position the dampener provides a greater level of dampening and in the open position the dampener provides a lower level of dampening. The method further includes moving the dampener from the closed position to the open position in response to an acceleration force over the acceleration threshold and, after the valve is moved from the closed position to the open position, delaying the valve from returning to the closed position before completion of a dampener compression stroke and before the time interval elapses.
A preferred embodiment is a shock absorber including a first portion. The shock absorber also includes a valve move
Fox Factory, Inc.
Knobbe Martens Olson & Bear LLP
Schwartz Chris
LandOfFree
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