# US 2019/0316650 A1 · Limiting system for a vehicle suspension component > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0316650 A1 - Document ID: US20190316650A1 - Status: Published application - Kind: A1 - Application number: 16/457,274 - Filed: 2019-06-28 - Published: 2019-10-17 - Earliest claimed: 2013-03-10 - Assignees: Oshkosh Defense, LLC - Applicants: Oshkosh Defense, LLC - Inventors: Patrick S. Dillman; Erik S. Ellifson; Aaron J. Rositch - Web page: https://patentgrep.com/patent/US20190316650A1 ## CPC - F16F 9/49: Stops limiting fluid passage, e.g. hydraulic stops {or elastomeric elements inside the cylinder which contribute to changes in fluid damping (fluid-actuated displacement devices with means for accelerating or decelerating the stroke F15B15/22)} - B60G 17/08: Characteristics of fluid dampers (adjusting fluid dampers in general F16F9/44 - F16F9/53) - F16F 9/16: involving only straight-line movement of the effective parts {(wing closers or openers with liquid piston brakes E05F3/04)} - F16F 9/368: {Sealings in pistons} - F16F 9/512: Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} - F16F 15/161: {characterised by the fluid damping devices, e.g. passages, orifices (F16F15/162 takes precedence)} - F16F 2222/12: Fluid damping - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00}) ## Abstract The damper assembly includes a tubular member, a rod, a primary piston, a secondary piston, and a resilient member. The tubular member includes a sidewall and a cap positioned at an end of the sidewall. The sidewall and the cap define an inner volume. The sidewall includes a shoulder separating the tubular member into a first portion and a second portion. The resilient member is disposed between the secondary piston and the cap and thereby is positioned to bias the secondary piston into engagement with the shoulder. ## Claims ### Claim 1 A damper assembly, comprising: a tubular member including a sidewall and a cap positioned at an end of the sidewall, the sidewall and the cap defining an inner volume, wherein the sidewall comprises a first portion coupled with a second portion of the sidewall, wherein the first portion and the second portion define a shoulder of the sidewall; a rod extending within the inner volume; a primary piston positioned within the inner volume and coupled to the rod, the primary piston defining a first contact surface; a secondary piston including a body member having a second contact surface, an opposing second surface, and an inner cylindrical face defining a central aperture that receives the rod, the secondary piston defining a channel extending from the inner cylindrical face to an outer periphery of the body member, wherein the primary piston and the secondary piston separate the inner volume into a first working chamber, a second working chamber, and a recoil chamber; and a resilient member disposed between the secondary piston and the cap and thereby positioned to bias the secondary piston into engagement with the shoulder; wherein the first contact surface and the channel are configured to cooperatively define a flow conduit upon engagement between the primary piston and the secondary piston; wherein the second contact surface is configured to engage the first contact surface such that fluid is directed along a primary flow path from the recoil chamber to the second working chamber through the central aperture and the flow conduit upon engagement between the primary piston and the secondary piston. ### Claim 2 (depends on 1) The damper assembly of claim 1, wherein the primary piston is moveable within the tubular member between a first location, an intermediate location, and an end of stroke, and wherein the primary piston is configured to maintain engagement with the secondary piston between the intermediate location and the end of stroke. ### Claim 3 (depends on 1) The damper assembly of claim 1, wherein the recoil chamber is defined between the opposing second surface of the secondary piston and the cap. ### Claim 4 (depends on 2) The damper assembly of claim 2, wherein the damper assembly provides a base level of damping as the primary piston moves between the first location and the intermediate location and an increased level of damping as the primary piston moves between the intermediate location and the end of stroke. ### Claim 5 (depends on 1) The damper assembly of claim 1, wherein the primary piston, the first portion, and the second portion have circular cross-sectional shapes. ### Claim 6 (depends on 5) The damper assembly of claim 5, wherein the first portion has a first diameter and the second portion has a second diameter, wherein the first diameter is greater than the second diameter, and wherein the transition between the first portion and the second portion defines the shoulder. ### Claim 7 (depends on 6) The damper assembly of claim 6, wherein the diameter of the primary piston is less than the second diameter such that the primary piston is extendable along the length of the tubular member. ### Claim 8 (depends on 1) The damper assembly of claim 1, further comprising a seal disposed between the outer periphery of the secondary piston and the sidewall of the tubular member. ### Claim 9 A damper assembly, comprising: a housing having an end cap and defining an inner volume, the housing comprising a first portion coupled with a second portion, wherein a transition between the first portion and the second portion defines a shoulder; a primary piston positioned within the housing; and a limiter positioned between the primary piston and the end cap, the limiter comprising: a damper piston including a body member having a contact surface, an opposing second surface, and an inner cylindrical face that defines an aperture through a central portion of the body member, the primary piston and the damper piston separating the inner volume into a first working chamber, a second working chamber, and a recoil chamber; and a resilient member disposed within the recoil chamber, between the opposing second surface of the damper piston and the end cap, the resilient member thereby positioned to bias the damper piston into engagement with the shoulder; and a rod coupled to the primary piston and extending through the aperture defined by the damper piston; wherein the damper piston defines a channel extending laterally outward from the inner cylindrical face across the contact surface to an outer periphery of the body member, wherein the primary piston and the channel are configured to cooperatively define a first flow conduit upon engagement between the primary piston and the damper piston; and wherein an outer surface of the rod and the inner cylindrical face of the damper piston define a second flow conduit, and wherein the first flow conduit and the second flow conduit cooperate to define a main flow path so that fluid is directed from the recoil chamber to the second working chamber through the central aperture upon engagement between the primary piston and the damper piston. ### Claim 10 (depends on 9) The damper assembly of claim 9, wherein the primary piston, the first portion, and the second portion have circular cross-sectional shapes. ### Claim 11 (depends on 10) The damper assembly of claim 10, wherein the first portion has a first diameter and the second portion has a second diameter, wherein the first diameter is greater than the second diameter, and wherein the transition between the first portion and the second portion defines the shoulder. ### Claim 12 (depends on 11) The damper assembly of claim 11, wherein the diameter of the primary piston is less than the second diameter such that the primary piston is extendable along the length of the housing. ### Claim 13 (depends on 12) The damper assembly of claim 12, wherein the primary piston and the housing cooperatively define a space around an outer periphery of the primary piston thereby providing a flow path around the outer periphery of the primary piston. ### Claim 14 (depends on 9) The damper assembly of claim 9, wherein an end of the rod is coupled to the primary piston. ### Claim 15 (depends on 9) The damper assembly of claim 9, wherein the primary piston is moveable within the housing between a first location, an intermediate location, and an end of stroke, and wherein the primary piston is configured to maintain engagement with the limiter between the intermediate location and the end of stroke. ### Claim 16 (depends on 15) The damper assembly of claim 15, wherein the damper assembly provides a base level of damping as the primary piston moves between the first location and the intermediate location and an increased level of damping as the primary piston moves between the intermediate location and the end of stroke. ### Claim 17 (depends on 9) The damper assembly of claim 9, wherein the recoil chamber is defined between the opposing second surface of the damper piston and the end cap. ### Claim 18 (depends on 9) The damper assembly of claim 9, wherein the limiter further comprises a ring coupling the damper piston to the housing, wherein the ring comprises a polymeric seal. ### Claim 19 A damper assembly, comprising: a housing having an end cap and defining an inner volume, wherein the housing comprises a first portion fixedly coupled with a second portion of the housing, wherein a transition between the first portion and the second portion defines a shoulder of the housing; a primary piston positioned within the housing; and a limiter positioned between the primary piston and the end cap, the limiter comprising: a damper piston including a body member having a contact surface, an opposing second surface, and an inner cylindrical face that defines an aperture through a central portion of the body member, the primary piston and the damper piston separating the inner volume into a first working chamber, a second working chamber, and a recoil chamber; and a resilient member disposed within the recoil chamber, between the opposing second surface of the damper piston and the end cap, the resilient member thereby positioned to bias the damper piston into engagement with the shoulder; and a rod coupled to the primary piston and extending through the aperture defined by the damper piston; wherein the damper piston defines: a channel extending laterally outward from the inner cylindrical face across the contact surface to an outer periphery of the body member; and an inner channel within the inner cylindrical face between the contact surface and the opposing second surface; wherein the channel and the primary piston define a flow conduit upon engagement between the primary piston and the damper piston; and wherein the flow conduit and the inner channel directly fluidly couple to cooperatively define a primary flow path from the recoil chamber; wherein fluid is directed from the recoil chamber along the primary flow path through the inner channel and the flow conduit to the second working chamber as the damper piston is forced to translate by the primary piston. ### Claim 20 (depends on 19) The damper assembly of claim 19, wherein the first portion has a first diameter and the second portion has a second diameter, wherein the first diameter is greater than the second diameter, and wherein the transition between the first portion and the second portion defines the shoulder and wherein the diameter of the primary piston is less than the second diameter such that the primary piston is extendable along the length of the housing.