Steering mechanism for a zero turning radius vehicle

A driving and steering mechanism for a vehicle having a pair of driving wheels, comprising:

• reversible motor means for driving each one of said pair of driving wheels, including control means for controlling the speed and direction of rotation of each one of said pair of driving wheels independently of the other, thereby controlling the actual speed and actual steerage of the vehicle;
• a steering mechanism operable by the operator of the vehicle to prescribe a steerage for the vehicle and having a first output corresponding to said prescribed steerage;
• an accelerator mechanism operable by the operator of the vehicle to prescribe a speed for the vehicle and having a second output corresponding to said prescribed speed, said accelerator mechanism also having a neutral position in which no speed is prescribed;
• integrator linkage means, disposed between said control means and said first and second outputs, for integrating said first and second outputs into an input for said control means;
• wherein when said steering mechanism and said accelerator mechanism are in a first state, said control means, in response to a first integrated input corresponding to said first state, operates to proportion the relative speeds of said pair of driving wheels, and
• when said steering mechanism and accelerator mechanism are in a second state in which said accelerator mechanism is in said neutral position, said control means in response to a second integrated input corresponding to said second state, operates to produce opposite directions of rotation for each of said pair of driving wheels.

A driving and steering mechanism for a vehicle having a pair of driving wheels, comprising:

• reversible motor means for driving each one of said pair of driving wheels, including control means for controlling the speed and direction of rotation of each one of said pair of driving wheels independently of the other, thereby controlling the forward/reverse motion, actual speed, and actual steerage of the vehicle;
• a steering mechanism operable by the operator of the vehicle to prescribe a steerage for the vehicle and having a first output corresponding to said prescribed steerage;
• an accelerator mechanism operable by the operator of the vehicle to simultaneously prescribe a speed and a forward-reverse direction for the vehicle and having a second output corresponding to said prescribed speed and forward-reverse direction;
• and
• integrator linkage means for integrating said first and second outputs into an input for said control means, whereby said control means coordinates operation of said motor means such that the speed and direction of rotation of each one of said pair of driving wheels is proportioned according to said input to produce said actual speed, said actual steerage and said forward/reverse motion of the vehicle.

A driving and steering mechanism for a vehicle having a pair of driving wheels, comprising:

• reversible motor means for driving each one of said pair of driving wheels, including control means for controlling the speed and direction of rotation of each one of said pair of driving wheels independently of the other, thereby controlling the forward/reverse motion, actual speed and actual steerage of the vehicle;
• a steering mechanism, including a rotatable steering wheel, operable by the operator of the vehicle to prescribe a steerage for the vehicle and having a first output corresponding to said prescribed steerage;
• an accelerator mechanism, including a pivotable foot pedal, for prescribing a speed for the vehicle and including a second output corresponding to said prescribed speed;
• integrator means for integrating said first and second outputs into a third output, said third output being applied to said control means, said integrator means being continuously operable while the vehicle is in motion to provide changes in the forward/reverse motion, actual speed and actual steerage of the vehicle while said steering wheel and said foot pedal are simultaneously operated by the operator of the vehicle, and including means for preventing tipping of the vehicle by reducing said actual steerage relative to said prescribed steerage as said prescribed speed is increased, and by limiting the prescribed speed to a predetermined maximum value for each prescribed steerage such that said predetermined maximum speed value is decreased as the prescribed steerage is increased.

In a vehicle having a pair of driving wheels, the improvement comprising:

• a steering mechanism rotatably mounted to the vehicle and rotatable by the operator of the vehicle to prescribe a steerage for the vehicle, said steering mechanism including a plate rotatable with said mechanism and having a pair of ends;
• an accelerator mechanism pivotably mounted to said vehicle and pivotable by the operator of the vehicle to prescribe a speed for the vehicle, said accelerator mechanism including a bracket pivotable with said mechanism and having a pair of ends;
• an independent driving and steering mechanism for each one of said driving wheels, each of said driving and steering mechanisms including:
• a reversible motor for driving said driving wheel;
• a transmission operably associated with said reversible motor for controlling the speed and direction of rotation of said motor;
• a control arm pivotably mounted at one end to said transmission and operable to control said transmission, said control arm having an input point;
• a floating link pivotably attached to said input point of said control arm at a control pivot at one end of said floating link, and having a first pivot distal said control pivot and a second pivot between said control pivot and said first pivot, wherein alternatively one of said first pivot and second pivot operates as a temporary fixed pivot axis for said floating link such that a displacement imposed on the other of said first pivot and second pivot causes said floating link to pivot about said temporary fixed pivot axis;
• a first link pivotably connected at one end of said first link to one of said first or said second pivots and pivotably connected at its other end to one of said pair of ends of said steering mechanism link, whereby rotation of said steering mechanism link causes said first link to translate, thereby imposing a displacement on said one of said first or said second pivots;
• and
• a second link pivotably connected at one end of said second link to the other of said first or said second pivots and pivotably connected at its other end to one of said pair of ends of said accelerator mechanism bracket, whereby pivoting of said accelerator mechanism bracket causes said second link to translate, thereby imposing a displacement on said other of said first or said second pivots.