Front bicycle suspension assembly with inertia valve

• US 8,297,417 B2
• Filed: 08/02/2010
• Issued: 10/30/2012
• Est. Priority Date: 08/30/2001
• Status: Expired due to Term

• Current Assignee: Fox Factory Incorporated
• Original Assignee: Fox Factory Incorporated
• Inventors: Fox, Robert C.
• Primary Examiner(s): Williams, Thomas J
• Application Number:
  US12/848,736
• Publication Number:
  US 20110031076A1
• Time in Patent Office: 820 Days
• Field of Search: 188/275, 188/315, 188/322.13, 188/322.14, 188/313, 188/314, 280/276, 280/284
• US Class Current: 188/275
• CPC Class Codes: B62K 2025/048 with suspension manual adjustment details
• CPC Class Codes: B62K 25/04 for mounting axles resiliently on cycle frame or fork for sidecars, forecars or the like B62K27/06
• CPC Class Codes: B62K 25/08 for front wheel
• CPC Class Codes: B62K 25/286 the shock absorber being connected to the chain-stay via a linkage mechanism
• CPC Class Codes: F16F 9/064 Units characterised by the location or shape of the expansion chamber F16F9/068, F16F9/08 take precedence
• CPC Class Codes: F16F 9/34 Special valve constructions F16F9/44, F16F9/50 take precedence; filtering details F16F9/3285 ; valves in general F16K; Shape or construction of throttling passages
• CPC Class Codes: F16F 9/504 Inertia , i.e. acceleration,-sensitive means
• CPC Class Codes: Y10T 29/494 Fluidic or fluid actuated device making

Abstract

A front bicycle suspension assembly having an inertia valve is described. The front bicycle suspension assembly may include at least upper and lower telescoping tubes and include a damping tube containing an inertia valve. The inertia valve may include an inertia mass movable along the outer surface of a valve shaft as the inertia valve moves between first and second positions.

Claims

1. A bicycle suspension assembly, comprising:

a damper body having a longitudinal axis and containing damping fluid;

a piston coupled to a piston rod;

the piston and a portion of the piston rod movable along the longitudinal axis of, and within, the damper body;

a reservoir including a reservoir tube, an inner surface of the reservoir tube, and a moveable sealed barrier partially defining a variable volume reservoir chamber, wherein the longitudinal axis of the damper body and a longitudinal axis of the reservoir tube are non-coaxial and non-parallel;

a fluid path between the damper body and the reservoir chamber for conveying fluid flow from the damper body to the reservoir chamber during a compression stroke, as the piston rod moves further into the damper body;

an inertia valve for at least partially controlling the fluid flow through the fluid path, the inertia valve positioned within the reservoir tube and including;

(1) an inertia mass, the inertia mass including an uppermost encircling portion immediately adjacent to and encircling a shaft and through which an upper end of a shaft protrudes; and

(2) whereby in response to an upward acceleration exceeding a predetermined acceleration threshold, the inertia mass is movable along the shaft from a first position downward towards a second position;

the first position limited by a stop and the inertia mass being biased towards the stop by a biasing member; and

whereby the fluid path is configured so, when the inertia mass has moved away from the first position and during compression, as the piston rod moves further into the damper body, fluid enters the reservoir tube at a first location relative to the inertia mass;

flows within an interior hollow portion of the shaft; and

then exits the interior hollow portion of the shaft at a second location relative to the inertia mass.

2. The bicycle suspension assembly of claim 1, wherein the fluid path includes a pressure-relief valve.

3. The bicycle suspension assembly of claim 1, wherein the moveable sealed barrier comprises a floating piston.

4. The bicycle suspension assembly of claim 3, wherein the floating piston is positioned above the inertia valve.

5. An acceleration-responsive bicycle suspension assembly, comprising:

a damper body having a damper bore defining a damper primary axis and partially defining a damping chamber containing damping fluid;

a piston rod slidably and sealingly engaged with the damper body, and configured to expel damping fluid from the damping chamber during a compression stroke;

a reservoir body having a reservoir bore defining a reservoir axis non-coaxial with the damper primary axis, the reservoir bore partially defining a variable-volume fluid reservoir configured to receive damping fluid expelled from the damping chamber;

a movable barrier, disposed within the reservoir body, separating the fluid reservoir from a pressurized gas chamber;

an inertia valve, associated with the reservoir body, including an inertia mass slidably mounted on a valve shaft and movable between at least a first position and a second position, wherein;

a) the valve shaft defines a flow passage extending over at least a portion of the length of the valve shaft;

b) the first position is defined by a maximum upward position of the inertia mass as limited by a stop;

c) the inertia mass is upwardly-biased by a biasing member toward the first position;

d) the second position is below the first position, the inertia mass being configured to move from the first position towards the second position in response to an upward acceleration exceeding a threshold;

a fluid flow circuit, extending from the damping chamber to the fluid reservoir and including the flow passage in the valve shaft, for conveying fluid flow from the damping chamber to the fluid reservoir during the compression stroke, the fluid flow circuit having a fluid flow resistance at least partially controlled by the inertia valve, such that the fluid flow resistance when the inertia mass is in the first position is greater than the fluid flow resistance when the inertia mass is in the second position; and

wherein the fluid flow circuit is configured such that, during operation and with the inertia mass in the second position, compression fluid flow;

a) enters the valve shaft at a location below the inertia mass and flows upward within the valve shaft through the inertia mass, while being substantially separated from direct contact with the inertia mass;

b) exits the valve shaft and flows into the fluid reservoir at a location generally above the inertia mass via one or more flow ports defined by the valve shaft;

c) defines a plurality of flow lines within the fluid reservoir, the flow lines being generally contained within a fluid volume above the inertia mass.

6. The acceleration-responsive bicycle suspension assembly of claim 5, wherein the movable barrier comprises a floating piston.

7. The acceleration-responsive bicycle suspension assembly of claim 5, wherein during the compression stroke:

a) with the inertia mass in the first position, fluid flow from the damping chamber to the fluid reservoir via the one or more flow ports is substantially restricted; and

b) with the inertia mass in the second position, fluid flow from the damping chamber to the fluid reservoir via the one or more flow ports is substantially permitted.

8. A bicycle suspension assembly, comprising:

a damper body having a longitudinal axis and containing damping fluid;

a piston coupled to a piston rod;

the piston and a portion of the piston rod movable along the longitudinal axis of, and within, the damper body;

a reservoir including a reservoir tube, an inner surface of the reservoir tube, and a moveable sealed barrier partially defining a variable volume reservoir chamber, wherein the moveable sealed barrier comprises a floating piston that is positioned above an inertia valve;

a fluid path between the damper body and the reservoir chamber for conveying fluid flow from the damper body to the reservoir chamber during a compression stroke, as the piston rod moves further into the damper body;

the inertia valve for at least partially controlling the fluid flow through the fluid path, the inertia valve positioned within the reservoir tube and including;

(1) an inertia mass, the inertia mass including an uppermost encircling portion immediately adjacent to and encircling a shaft and through which an upper end of a shaft protrudes; and

(2) whereby in response to an upward acceleration exceeding a predetermined acceleration threshold, the inertia mass is movable along the shaft from a first position downward towards a second position;

the first position limited by a stop and the inertia mass being biased towards the stop by a biasing member; and

whereby the fluid path is configured so, when the inertia mass has moved away from the first position and during compression, as the piston rod moves further into the damper body, fluid enters the reservoir tube at a first location relative to the inertia mass;

flows within an interior hollow portion of the shaft; and

then exits the interior hollow portion of the shaft at a second location relative to the inertia mass.

9. The bicycle suspension assembly of claim 8, wherein the fluid path includes a pressure-relief valve.

10. The bicycle suspension assembly of claim 8, wherein the longitudinal axis of the damper body and a longitudinal axis of the reservoir tube are non-coaxial and non-parallel.