# US 10,371,227 B2 · Shock absorber with pressure-controlled damping

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- Number: US 10,371,227 B2
- Document ID: US10371227B2
- Status: Granted
- Kind: B2
- Application number: 15/493,934
- Filed: 2017-04-21
- Published: 2017-08-10
- Granted: 2019-08-06
- Earliest claimed: 2003-07-08
- Assignees: Fox Factory, Inc.
- Applicants: Fox Factory, Inc.
- Inventors: Dustin F. Janes
- Web page: https://patentgrep.com/patent/US10371227B2

## CPC

- F16F 9/44: Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction (F16F9/53, {F16F13/26} take precedence; temperature correction only F16F9/52)
- B60G 13/08: hydraulic
- B60G 15/12: and fluid damper
- B60G 17/056: Regulating distributors or valves {for hydropneumatic systems}(B60G17/044 - B60G17/048, {B60G17/0416} take precedence; {Fluid interconnection systems to control vehicle inclination B60G21/06, B60G21/10}; valves per se F16K)
- B60G 17/08: Characteristics of fluid dampers (adjusting fluid dampers in general F16F9/44 - F16F9/53)
- F16F 9/064: {Units characterised by the location or shape of the expansion chamber (F16F9/068, F16F9/08 take precedence)}
- F16F 9/065: {Expansion chamber provided on the upper or lower end of a damper, separately there from or laterally on the damper}
- F16F 9/19: with a single cylinder {and of single-tube type}
- F16F 9/3235: {of cylinders (F16F9/483 takes precedence)}
- 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
- F16F 9/3405: {Throttling passages in or on piston body, e.g. slots (F16F9/344, F16F9/3481 take precedence)}
- F16F 9/516: resulting in the damping effects during contraction being different from the damping effects during extension {, i.e. responsive to the direction of movement (F16F9/504 takes precedence)}
- B60G 2202/154: with an accumulator
- B60G 2500/11: Damping valves
- B60G 2500/20: Spring action or springs
- B60G 2500/206: Variable pressure accumulators for hydropneumatic suspensions
- B62K 25/14: with single arm on each fork leg
- F16F 9/20: with the piston-rod extending through both ends of the cylinder {, e.g. constant-volume dampers}
- F16F 9/3214: {of pistons (F16F9/0227 and F16F9/36 take precedence; throttling passages in or on piston body F16F9/3405)}
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00})
- B62K: CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE

## Abstract

A damper includes a pressure-sensitive damping control circuit that selectively permits fluid flow from a first chamber to a second chamber. A piston varies a volume of the first chamber. A blow-off piston is movable between a closed position, wherein fluid flow through the control circuit is substantially prevented, and an open position, wherein fluid flow through the control circuit is permitted. The damper also includes a first source of pressure. A fluid pressure created by compression of the damper applies an opening force to the blow-off piston moving the blow-off piston in a direction toward the open position against a resistance force provided by the first source of pressure. The resistance force exceeds the opening force until the pressure created by forces tending to insert the piston rod into the first fluid chamber exceeds the pressure in the first source of pressure by a predetermined amount.

## Claims

### Claim 1

A pressure-sensitive damper, comprising:
a first cylinder at least partially defining a first fluid chamber, said first fluid chamber containing a damping fluid;
a damping piston for reciprocal motion within said first cylinder;
a piston rod comprising:
a first end connected to said damping piston; and
a second end extending through an end of said first cylinder;
a second cylinder at least partially defining a second fluid chamber in fluid communication with said first cylinder;
a compression damping plate fixed in said second cylinder;
at least one passage in said compression damping plate through which said damping fluid, which is displaced by a movement of said piston rod, flows in a first direction from said first fluid chamber to said second fluid chamber to achieve a first fluid flow;
a gas chamber in communication with said second fluid chamber;
a valve for generating a resistance force to said first fluid flow, wherein said resistance force varies according to an amount of force communicated to said valve by said gas chamber, wherein said valve comprises:
a blow-off piston having a first position in engagement with said at least one passage and a second position removed from said at least one passage;
an intensifier piston comprising:
a first end; and
a second end, wherein a pressure within said gas chamber generates a force on said first end of said intensifier piston and generates an intensified pressure at said second end of said intensifier piston, wherein said intensified pressure is communicated to said blow-off piston to create a first force urging said blow-off piston toward said first position; and
an intermediate chamber, wherein a pressure within said intermediate chamber acts on said intensifier piston, said pressure within said intermediate chamber providing force on said second end of said intensifier piston tending to counteract an amount of said force generated on said first end of said intensifier piston by said pressure within said gas chamber.

### Claim 2 (depends on 1)

The pressure-sensitive damper of claim 1, further comprising:
a by-pass circuit adapted to permit a flow of said damping fluid in said first direction through said compression damping plate without passing through said at least one passage.

### Claim 3 (depends on 1)

The pressure-sensitive damper of claim 1, wherein said pressure within said gas chamber is adjustable.

### Claim 4 (depends on 1)

The pressure-sensitive damper of claim 1, wherein said pressure within said intermediate chamber is adjustable.

### Claim 5 (depends on 1)

The pressure-sensitive damper of claim 1, wherein said gas chamber comprises:
a pressurized, compressible chamber containing compressible fluid.

### Claim 6 (depends on 1)

The pressure-sensitive damper of claim 1, further comprising:
an adjustment mechanism, said adjustment mechanism configured to adjust a pressurization force applied to said intermediate chamber by said intensifier piston, said adjustment mechanism comprising:
an annular chamber with externally-adjustable volume.

### Claim 7 (depends on 1)

The pressure-sensitive damper of claim 1, wherein said blow-off piston is movable in an axial direction between said first position and said second position.