# US 4,391,343 A · Retractable tracted cart > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,391,343 A - Document ID: US4391343A - Status: Granted - Kind: A - Application number: 06/201,035 - Filed: 1980-10-27 - Granted: 1983-07-05 - Earliest claimed: 1979-11-29 - Inventors: Frederick A. Deare - Web page: https://patentgrep.com/patent/US4391343A ## CPC - B62D 63/061: {Foldable, extensible or yielding trailers (foldable caravans B60P3/34; adjustable chassis frames B62D21/14)} - B62D 55/04: with tracks and alternative ground wheels, e.g. changeable from endless track vehicle into wheeled vehicle and vice versa {(for multi-purpose tractors B62D49/0635)} - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) ## Abstract A convertible traction device for permitting a road vehicle to be used in an off-road configuration is described. The device is provided as a trailer having a pair of retractable road wheels with a pair of traction belt assemblies mounted thereon. The traction belt assemblies each include an endless belt, a plurality of support wheels about which the belt is entrained and a supporting framework, each assembly being pivotally attached to the trailer chassis. During towing the road wheels support the trailer on the ground with the traction belt assemblies being held in a retracted position above the trailer platform. For off-road use the traction belt assemblies are pivoted downwardly until the belts engage the ground, the assemblies are locked in position and the road wheels are retracted. The vehicle is driven onto the platform so that the drive wheels thereof engage drive rollers mounted in the trailer chassis, which rollers, as the vehicle's drive wheels rotate, impart driving movement to the traction belt. Operator controlled brakes on the drive rollers are used to stop the device and to turn the device to the left or the right. ## Claims ### Claim 1 A convertible traction device for use with a vehicle having at least two drive wheels, comprising: a trailer for towing behind said vehicle and having a platform sized to receive the vehicle, hitch means and a road wheel assembly; first means for selectively moving said road wheels between an operative ground engaging position and a retracted position, relative to said platform; traction means for each side of said trailer and including a traction belt and belt supporting means; second means for selectively pivotally moving the traction means between a retracted position above said platform and an operative ground engaging position outboard of the adjacent road wheel; means for locking said traction means and said road wheels in their respective operative and retracted positions; and drive means in said platform, engageable by the vehicle drive wheels, for driving said traction means when the vehicle is on the platform and the traction means are in their operative position. ### Claim 2 (depends on 1) The traction device of claim 1, wherein said road wheel assembly includes a pivotable suspension member connected to said platform and carrying road wheels rotatably thereon, and said first means comprises a threaded shaft bearingly mounted on said platform longitudinally thereof, a nut member threaded on said shaft and a link member interconnecting said nut member and said suspension member, rotation of said shaft imparting longitudinal movement to said nut member and, in turn, pivotal movement to said suspension member via said link member. ### Claim 3 (depends on 2) The traction device of claim 2, including a motor on said platform, and a gear selector including first and second selectable gear means therein, a selector shaft driven by said motor and a selector gear slidably mounted on said selector shaft for selected engagement with said first or said second gear means said first gear means being connected to said threaded shaft. ### Claim 4 (depends on 3) The traction device of claim 3 including a winch mounted on said platform adjacent said gear selector and manually selectable clutch means for engaging said selector shaft with said winch for driving said winch. ### Claim 5 (depends on 3) The traction device of claim 3 wherein said gear selector includes a housing mounted on said platform and containing said first and second gear means, said selector shaft and said selector gear, each of said first and second gear means being a single-faced bevel gear and having locking teeth on the back surface thereof, and said selector gear being a double-faced bevel gear. ### Claim 6 (depends on 5) The traction device of claim 5 wherein said belt supporting means includes a framework pivotally connected to said platform via a plurality of parallel longitudinally spaced pivot arms, said framework also including means rotatably mounting a plurality of aligned longitudinally spaced belt supporting wheels and a plurality of bogie-wheel assemblies, said traction belt being tensioned over said belt supporting wheels and said bogie-wheel assemblies. ### Claim 7 (depends on 6) The traction device of claim 6 wherein said framework is provided with means for extending longitudinally one portion of said framework relative to the remainder thereof for adjusting the tension in said traction belt. ### Claim 8 (depends on 6) The traction device of claim 6 wherein said second means includes a hoist shaft bearingly mounted on said platform with one end thereof connected to said second gear means, a plurality of windlass means keyed to said shaft, there being one windlass means positioned between each pair of opposing pivot arms of the opposing belt supporting means, and cable means connecting each windlass means to the opposing pivot arms whereby rotation of said hoist shaft in one direction will move said traction means in one direction between said retracted and operative positions and opposite rotation of the hoist shaft will move the traction means in the other direction between said operative and retracted positions. ### Claim 9 (depends on 6, 8) The traction device of claim 6 or 8 wherein the locking means includes (a) spring biased pawl means engageable with the teeth provided on the back surface of said first and second gear means to prevent rotation thereof, and disengageable upon engagement of said selector gear with the selected one of said gear means whereby only one of said first and second gear means is engageable at one time, by said selector gear; and (b) a pair of locking bars movable longitudinally on said platform, there being one locking bar for each traction means, each said locking bar having a portion engageable with each said pivot arm when said traction means is in the operative position to prevent unwanted movement thereof to the retracted position. ### Claim 10 (depends on 6) The traction device of claim 6 wherein said drive means includes, for each traction means a pair of drive rollers engageable by the vehicle drive wheel, an idler roller engageable by said drive rollers, a drive shaft mounting said idler roller at one end and a drive sprocket at the other end, said drive shaft being bearingly mounted in said framework, a driven sprocket on a shaft mounting one of said belt support wheels and a drive chain interconnecting said drive sprocket and said driven sprocket. ### Claim 11 (depends on 10) The traction device of claim 10 including a disc brake on each drive shaft, a brake housing surrounding a portion of the disc brake, brake pad within said housing and an electric brake actuator for actuating said brake pads into engagement with the disc brake. ### Claim 12 (depends on 11) The traction device of claim 11 including electric switch means operable to selectively actuate one or both of said disc brakes through the brake actuators.