Four wheel drive system
OwnerThomas Towles Lawson, Jr.inventor
Life of this patent
Estimating the term…
Abstract
A four wheel drive system for bilaterally symmetric vehicles is characterized by separate drive systems for the front and rear wheels. Each drive system is operable to independently drive each wheel. The rear wheels of the vehicle are steering wheels which are connected with the vehicle frame for independent rotation about a vertical axis. Steering and driving of the wheels is controlled by a controller. The combination of independent steering for the rear wheels and independent powering of all four wheels provides the vehicle with a zero turning radius for improved mobility as well as improved traction on unstable surfaces.
Claims14
A four wheel drive system for a bilaterally symmetrical vehicle having pairs of front and rear wheels, respectively, comprising
- (a) a first drive system for independently rotating each of the front wheels in forward and reverse directions about a horizontal axis to propel the vehicle;
- (b) a second drive system for independently rotating each of the rear wheels about a horizontal axis at similar speeds in the same direction to propel the vehicle;
- (c) said rear wheels further being connected with said vehicle for rotation about vertical axes, respectively, beyond 180 degrees;
- (d) a third drive system independently rotating the rear wheels about vertical axes to steer the vehicle;
- and
- (e) a controller connected with said first, second and third drive systems for controlling the operation thereof to steer and propel the vehicle, said controller operating said first drive system to simultaneously rotate said front wheels in opposite directions when executing a sharp turn approaching a turning radius of zero.
A steering mechanism for a vehicle, comprising
- (a) a pair of axles;
- (b) a pair of wheels connected with said axles for driven rotation about horizontal axes, respectively, said wheels further being actively rotatable through greater than 180 degrees about vertical axes with respect to said axles;
- (c) a first drive system connected with the front wheels to drive said wheels in forward and reverse directions about said horizontal axes and a second drive system connected with said pair of wheels to independently rotate said wheels about said vertical axes;
- and
- (d) a controller connected with said first and second drive systems for controlling the operation thereof to steer and propel the vehicle in accordance with operator input to said controller, said controller operating said first drive system to simultaneously rotate said front wheels in opposite directions when executing a sharp turn approaching a turning radius of zero.
A four wheel drive system for a bilaterally symmetrical vehicle having a longitudinal axis and pairs of front and rear wheels, respectively, comprising
- (a) a propelling drive system for rotating each of the front wheels in forward and reverse directions about a horizontal axis to propel the vehicle, said drive system further rotating each of the rear wheels about a horizontal axis at similar speeds in the same direction to propel the vehicle;
- (b) the rear wheels further being connected with said vehicle for rotation about vertical axes, respectively;
- (c) a steering drive system for rotating the rear wheels about vertical axes up to 90° relative to said vehicle longitudinal axis to steer the vehicle;
- and
- (e) a controller connected with said propelling and steering drive systems for controlling the operation thereof to propel and steer the vehicle, said controller operating said propelling drive system to simultaneously rotate said front wheels in opposite directions when executing a sharp turn approaching a turning radius of zero.
Dependencies are inferred from the claim text.