# US 9,039,018 B1 · Four-wheel independent suspension system for an electric wheelchair > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,018 B1 - Document ID: US9039018B1 - Status: Granted - Kind: B1 - Application number: 14/249,797 - Filed: 2014-04-10 - Granted: 2015-05-26 - Earliest claimed: 2014-04-10 - Applicants: Chung-Chuan Lin - Inventors: Chung-Chuan Lin - Web page: https://patentgrep.com/patent/US9039018B1 ## CPC - B60G 3/12: the arm being essentially parallel to the longitudinal axis of the vehicle - A61G 5/045: {Rear wheel drive} - A61G 5/1078: {with shock absorbers or other suspension arrangements between wheels and frame} - A61G 5/1089: {Anti-tip devices} - B60G 3/145: {the arm forming the axle housing} - B60G 11/225: {Neidhart type rubber springs} - B60G 11/24: characterised by means specially adapted for attaching the spring to axle or sprung part of the vehicle - A61G 2200/34: sitting - B60G 2202/142: subjected to shear, e.g. Neidhart type - B60G 2300/24: Wheelchairs - B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00}) - A61G: TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS (appliances for aiding patients or disabled persons to walk A61H3/00); OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES (embalming corpses A01N1/00) ## Abstract A four-wheel independent suspension system for an electric wheelchair includes a chassis, two front wheels each fixed to a front rod respectively, and two rear wheels each fixed to a rear rod respectively. The chassis includes a rail extending in a width direction of the chassis, each of the front and rear rods has one end connected to a square first connecting sleeve, in the first connecting sleeve is disposed a first shock absorber which includes a rectangular outer pipe, and a rectangular inner pipe disposed in and rotated degrees with respect to the outer pipe, the edges of the inner pipe are abutted against the inner surface of the outer pipe, between each of the edges of the inner pipe and the inner space of the outer pipe is disposed an elastic rubber, the inner pipe of each of the first shock absorbers is sleeved on the rail. ## Claims ### Claim 1 A four-wheel independent suspension system for an electric wheelchair comprising: a chassis, two front wheels each fixed to a front rod respectively, and two rear wheels each fixed to a rear rod respectively; the four-wheel independent suspension system being characterized in that: the chassis is provided with a rail extending in a width direction of the chassis, each of the front rods and rear rods has one end connected to a first connecting sleeve which is square-shaped in cross section, in each of the first connecting sleeves is disposed a first shock absorber which includes a rectangular outer pipe, and a rectangular inner pipe disposed in and rotated degrees with respect to the outer pipe, so that edges of the inner pipe are abutted against the inner surface of the outer pipe, between each of the edges of the inner pipe and the inner space of the outer pipe is disposed an elastic rubber, the inner pipe of each of the first shock absorbers is sleeved on the rail, so that the front and rear wheels are independently suspended from the chassis via the connecting sleeves and the first shock absorbers. ### Claim 2 (depends on 1) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 1, wherein each of the first connecting sleeves includes a U-shaped frame and bolts, the U-shaped frame is sleeved on a corresponding one of the first shock absorbers and then fixed by the bolts and nuts. ### Claim 3 (depends on 2) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 2, wherein the front rods are connected to the first shock absorbers that are disposed in the first connecting sleeves that are connected to the front rods and extend outward and forward in an inclined manner, and the rear rods are connected to the first shock absorbers that are disposed in the first connecting sleeves that are connected to the rear rods and extend downward and backward in an inclined manner. ### Claim 4 (depends on 3) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 3 further comprising a safety rod, at a rear end of the chassis is disposed a hollow pipe which extends downward and backward, the hollow pipe has a top close end, inside the hollow pipe is disposed an elastic member, the safety rod is partially inserted in the hollow pipe and abutted against the elastic member. ### Claim 5 (depends on 4) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 4, wherein the hollow pipe is provided with two aligned slots in two opposite sides thereof, the safety rod is provided with an engaging protrusion on each of two opposite sides, and the engaging protrusions are engaged in the slots. ### Claim 6 (depends on 4) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 4, wherein the elastic members are springs. ### Claim 7 (depends on 4) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 4, wherein the safety rod is provided at a lower end thereof with two first wheels which are located at two sides of the safety rod. ### Claim 8 (depends on 3) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 3, wherein a second connecting sleeve is disposed at the rear end of the chassis, and in the second connecting sleeve is disposed a second shock absorber which is structurally the same as the first shock absorber, at two ends of an inner pipe of the second shock absorber are sleeved two suspension arms, and at lower ends of the suspension arms is fixed a second wheel. ### Claim 9 (depends on 1) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 1, wherein the front rods are connected to the first shock absorbers that are disposed in the first connecting sleeves that are connected to the front rods and extend outward and forward in an inclined manner, and the rear rods are connected to the first shock absorbers that are disposed in the first connecting sleeves that are connected to the rear rods and extend downward and backward in an inclined manner. ### Claim 10 (depends on 9) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 9 further comprising a safety rod, at a rear end of the chassis is disposed a hollow pipe which extends downward and backward, the hollow pipe has a top close end, inside the hollow pipe is disposed an elastic member, the safety rod is partially inserted in the hollow pipe and abutted against the elastic member. ### Claim 11 (depends on 10) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 10, wherein the hollow pipe is provided with two aligned slots in two opposite sides thereof, the safety rod is provided with an engaging protrusion on each of two opposite sides, and the engaging protrusions are engaged in the slots. ### Claim 12 (depends on 10) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 10, wherein the elastic members are springs. ### Claim 13 (depends on 10) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 10, wherein the safety rod is provided at a lower end thereof with two first wheels which are located at two sides of the safety rod. ### Claim 14 (depends on 9) The four-wheel independent suspension system for the electric wheelchair as claimed in claim 9, wherein a second connecting sleeve is disposed at the rear end of the chassis, and in the second connecting sleeve is disposed a second shock absorber which is structurally the same as the first shock absorber, at two ends of an inner pipe of the second shock absorber are sleeved two suspension arms, and at lower ends of the suspension arms is fixed a second wheel.