IP Library Granted Patent US 12,673,528
Granted Patent B2
US 12,673,528 · App. 18/113,021 · Granted Jul 7, 2026

Hydraulic cross-linked suspension

Inventors: Ivan Tong (San Diego, CA); Connor Randall (Salida, CO); Rick Strickland (Watsonville, CA)
Assignee: Fox Factory, Inc.
B60G17/08B60G17/021B60G2202/13B60G2202/24
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Quick Facts
Patent No.
US 12,673,528
App. No.
18/113,021
Granted
Jul 7, 2026
Kind
B2
Abstract

Disclosed herein is an accumulator comprising a cylinder, and an internal floating piston. The internal floating piston divides the cylinder into a spring chamber and a gas chamber, and the spring chamber allows fluid to flow. The accumulator further comprises a negative spring disposed in the spring chamber.

Claims (41)

1 . An accumulator comprising:

a cylinder;

an internal floating piston, to divide the cylinder into a spring chamber and a gas chamber, the spring chamber to allow fluid to flow, wherein any movement of said internal floating piston to move further into said gas chamber is based upon a fluid pressure on a side of said internal floating piston which does not face said gas chamber; and

a negative spring disposed in the spring chamber, said negative spring having a spring force such that a force on said internal floating piston from said gas chamber and a force from said negative spring are balanced.

2 . The accumulator of claim 1 further comprising:

a piston with at least one shim stack to meter fluid flow in and out of the spring chamber.

3 . The accumulator of claim 1 further comprising:

at least one adjustment plate to alter the stiffness of the accumulator.

4 . The accumulator of claim 1 further comprising:

a retainer fit to maintain the placement of the negative spring.

5 . The accumulator of claim 1 wherein, the gas pressure in the gas chamber is higher than the gas pressure in a reservoir gas chamber.

6 . The accumulator of claim 5 wherein, the negative spring is sized so that the force on the internal floating piston from the gas in the gas chamber is balanced by the combined force of the negative spring and the pressure from the reservoir gas chamber.

7 . An accumulator comprising:

a cylinder;

an internal floating piston, to divide the cylinder into a spring chamber and a gas chamber, the spring chamber to allow fluid to flow, wherein any movement of said internal floating piston to move further into said gas chamber is based upon a fluid pressure on a side of said internal floating piston which does not face said gas chamber;

a negative spring disposed in the spring chamber, said negative spring having a spring force such that a force on said internal floating piston from said gas chamber and a force from said negative spring are balanced; and

a piston with at least one shim stack to meter fluid flow in and out of the spring chamber.

8 . The accumulator of claim 7 further comprising:

at least one adjustment plate to alter the stiffness of the accumulator.

9 . The accumulator of claim 7 further comprising:

a retainer fit to maintain the placement of the negative spring.

10 . The accumulator of claim 7 wherein, the gas pressure in the gas chamber is higher than the gas pressure in a reservoir gas chamber.

11 . The accumulator of claim 10 wherein, the negative spring is sized so that the force on the internal floating piston from the gas in the gas chamber is balanced by the combined force of the negative spring and the pressure from the reservoir gas chamber.

12 . A cross-linked system comprising:

a first shock assembly;

a second shock assembly;

a first line fluidly coupled with a first rebound chamber of the first shock assembly and a second compression chamber of the second shock assembly, to allow fluid to flow between the first rebound chamber and the second compression chamber;

a second line fluidly coupled with a first compression chamber of the first shock assembly and a second rebound chamber of the second shock assembly, to allow fluid to flow between the first compression chamber and the second rebound chamber;

a reservoir, wherein the reservoir fluidly coupled to the first line and the second line; and

an accumulator fluidly coupled to said first line and said second line, said accumulator comprising:

a cylinder;

an internal floating piston, to divide the cylinder into a spring chamber and a gas chamber, the spring chamber to allow fluid to flow, wherein any movement of said internal floating piston to move further into said gas chamber is based upon a fluid pressure on a side of said internal floating piston which does not face said gas chamber; and

a negative spring disposed in the spring chamber, said negative spring having a spring force such that a force on said internal floating piston from said gas chamber and a force from said negative spring are balanced.

13 . The accumulator of claim 12 further comprising:

a piston with at least one shim stack to meter fluid flow in and out of the spring chamber.

14 . The accumulator of claim 12 further comprising:

at least one adjustment plate to alter the stiffness of the accumulator.

15 . The accumulator of claim 12 further comprising:

a retainer fit to maintain the placement of the negative spring.

16 . The accumulator of claim 12 wherein, the gas pressure in the gas chamber is higher than the gas pressure in a reservoir gas chamber.

17 . The accumulator of claim 16 wherein, the negative spring is sized so that the force on the internal floating piston from the gas in the gas chamber is balanced by the combined force of the negative spring and the pressure from the reservoir gas chamber.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 22, 2025
From: TONG, IVAN; RANDALL, CONNOR; STRICKLAND, RICK
To: FOX FACTORY, INC.
Reel/Frame 072333/0544 →
Continuity (2)
Provisional Application 63313023 · Feb 23, 2022
Related Publication 20230302867A1 · Sep 28, 2023
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