# US 8,770,592 B2 · Suspension with hydraulic preload adjust > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,592 B2 - Document ID: US8770592B2 - Status: Granted - Kind: B2 - Application number: 13/758,330 - Filed: 2013-02-04 - Published: 2013-08-08 - Granted: 2014-07-08 - Earliest claimed: 2012-02-03 - Assignees: Fox Factory, Inc. - Applicants: Christopher Paul Cox - Inventors: Christopher Paul Cox - Web page: https://patentgrep.com/patent/US8770592B2 ## CPC - B60G 17/0272: {the mechanical spring being a coil spring} - B60G 15/065: {characterised by the use of a combination of springs} - B60G 17/0152: {characterised by the action on a particular type of suspension unit (B60G17/01941 takes precedence)} - F16F 1/121: {adjustable, e.g. to modify spring characteristics} - F16F 13/007: {the damper being a fluid damper} - B60G 17/016: characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input {(B60G17/017 takes precedence)} - B60G 2202/312: The spring being a wound spring - B60G 2400/10: Acceleration; Deceleration - B60G 2400/20: Speed - B60G 2400/25: Stroke; Height; Displacement - B60G 2401/11: Electrostrictive transducers - B60G 2401/17: Magnetic/Electromagnetic - B60G 2500/22: Spring constant - B60G 2600/22: Magnetic elements - B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00}) - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION ## Abstract A shock absorber for a vehicle having a damper and a first and second springs mounted coaxially around the damper and a preload adjuster for partially compressing at least one of the springs independently of the compression stroke. In one embodiment the preload adjuster is remotely controllable. In another embodiment the shock absorber includes an additional mechanism for preloading at least one of the springs. ## Claims ### Claim 1 A shock absorber for a vehicle, comprising: a fluid-filled damper having a piston and rod for movement therein; a first and second springs mounted coaxially around the damper, the springs constructed and arranged to become compressed during a compression stroke of the damper; and a preload adjuster for partially compressing at least one of the springs independently of the compression stroke, the preload adjuster comprising a chamber, the chamber having a volume that remains constant throughout a compression stroke of the damper. ### Claim 2 (depends on 1) The shock absorber of claim 1, wherein the preload adjuster operates with a preload piston and the chamber is an expandable chamber to compress the at least one spring. ### Claim 3 (depends on 2) The shock absorber of claim 2, wherein the preload piston and chamber are annularly disposed around the damper. ### Claim 4 (depends on 3) The shock absorber of claim 3, wherein the preload adjuster is remotely controllable. ### Claim 5 (depends on 4) The shock absorber of claim 4, further including a remote control system for expanding the chamber, the control system comprising: a switch for operating a valve; and a conduit providing communication between the switch and valve. ### Claim 6 (depends on 5) The shock absorber of claim 5, wherein the conduit is a fluid conduit for carrying control fluid and the system includes a source of control fluid. ### Claim 7 (depends on 5) The shock absorber of claim 5, wherein the conduit is an electrical conduit for carrying a control signal. ### Claim 8 (depends on 1) The shock absorber of claim 1, wherein at least one of the springs includes an additional adjustment mechanism for compressing the at least one spring independently of the compression stroke. ### Claim 9 (depends on 8) The shock absorber of claim 8, wherein additional adjustment mechanism is a user-operable threaded mechanism. ### Claim 10 (depends on 1) The shock absorber of claim 1, further including an air spring. ### Claim 11 (depends on 1) The shock absorber of claim 1, wherein the springs are concentrically arranged around the damper. ### Claim 12 (depends on 1) The shock absorber of claim 1, wherein the chamber is fluid-filled. ### Claim 13 A remotely controllable shock absorber system for a vehicle comprising: at least two dampers associated with at least two wheels of the vehicle, each damper comprising: a cylinder with a piston for movement therein, the piston metering fluid in at least one direction therethrough; a first and second springs mounted coaxially around the damper, the springs constructed and arranged to become compressed during a compression stroke of the damper; a preload adjuster for partially compressing at least one of the springs independently of the compression stroke, the preload adjuster operable with a preload piston and expandable chamber, the chamber having a volume that remains constant throughout a compression stroke of the damper; and a remotely actuatable valve for expanding and contracting the expandable chamber. ### Claim 14 (depends on 13) The shock absorber system of claim 13, further including a switch associated with each damper, the switch arranged to cause at least one valve to operate based upon at least one characteristic of the vehicle. ### Claim 15 (depends on 14) The shock absorber system of claim 14, wherein the characteristic is at least two of vehicle speed, vehicle trajectory angular acceleration, damper rod velocity, and rod location in a damper cylinder. ### Claim 16 A shock absorber for a vehicle, comprising: a fluid-filled damper having a piston and rod for movement therein; at least one spring retained adjacent the rod at a first end and retained adjacent a damper cylinder at a second end whereby the spring becomes compressed during a compression stroke of the damper; and a preload adjuster for partially compressing the at least one spring independently of the compression stroke, the preload adjuster including an annular cylinder moveable independent of the damper cylinder and including an abutment structure formed on an outer surface thereof, the abutment structure constructed and arranged to maintain the at least one spring at the second end whereby the second end moves with the annular cylinder. ### Claim 17 (depends on 16) The shock absorber of claim 16, further including a second spring and a second abutment structure formed on the outer surface of the damper cylinder for retaining a second end of the second spring. ### Claim 18 (depends on 17) The shock absorber of claim 17, wherein at least one of the first or second abutment structures is axially movable along the damper cylinder.