Electric controls for hydrostatic transmissions

Claim 2

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators, and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, or a. a direction unit comprising first and second electrical resistances connected across a source of power, arranged in parallel with one another by connections between their ends, and extending generally in opposite directions from their connections with one another, said unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being conjointly movable with respect thereto; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second take-off leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances arranged in parallel with one another by connections between their ends and extending in opposite directions from their connections with one another; the first and second take-off leads, respectively, being connected with one connection and the other connection between the ends of the third and fourth resistances, the steering unit further comprising third and fourth leads contactable with the third and fourth resistances, respectively, and being connected with one actuator and the other actuator respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward movement of the joy stick to produce conjoint movement of the third and fourth resistances with respect to the third and fourth take-off leads in one direction and in the opposite direction, respectively.

Claim 3

In a vehicle in which two drive mechanisms are driven at the same speed in given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movment of the vehicle, and in opposite directions or at different speeds in the same direction for sterring of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions from their points of connection with one another, said unti further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being conjointly movable with respect thereto in a direction therealong; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second takeoff leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances arranged in parallel with one another by connections between their ends and extending in opposite directions from their connections with one another; the first and second takeoff leads, respectively, being connected with one connection and the other connection between the ends of the third and fourth resistances, the steering unit further comprising third and fourth leads contactable with the third and fourth resistances, respectively, and being connected with one actuator and the other actuator respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward movement of the joy stick to produce angular movements of the thrid and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 4

In a vehicle in which two drive mechanisms are driven at the same speed in given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movment of the vehicle, and in opposite directions or at different speeds in the same direction for sterring of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions from their points of connection with one another, said unti further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being conjointly movable with respect thereto in a direction therealong; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second takeoff leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances arranged in parallel with one another by connections between their ends and extending in opposite directions from their connections with one another; the first and second takeoff leads, respectively, being connected with one connection and the other connection between the ends of the third and fourth resistances, the steering unit further comprising third and fourth leads contactable with the third and fourth resistances, respectively, and being connected with one actuator and the other actuator respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward movement of the joy stick to produce angular movements of the thrid and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 5

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected across a source of power, arranged in parallel with one another by connections between their ends, and extending in opposite directions from their connections with one another, said unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second takeoff leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced ends and being in parallel with connections between their adjacent ends and between their remote ends, the first and second takeoff leads being connected to the adjacent ends and to the remote ends, respectively, of the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the connection between the adjacent ends thereof and being connected with one actuator and the other actuator, respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward moVement of the joy stick to produce angular movements of the third and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 6

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected across a source of power, arranged in parallel with one another by connections between their ends, and extending in opposite directions from their connections with one another, said unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second takeoff leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced ends and being in parallel with connections between their adjacent ends and between their remote ends, the first and second takeoff leads being connected to the adjacent ends and to the remote ends, respectively, of the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the connection between the adjacent ends thereof and being connected with one actuator and the other actuator, respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward moVement of the joy stick to produce angular movements of the third and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 7

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movment of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions from connections with one another, said unit further comprising first and second take-off leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second take-off leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced ends and being in parallel with connections between their adjacent ends and between their remote ends, the first and second takeoff leads being connected to the adjacent ends and to the remote ends, respectively, of the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the connection between the adjacent ends thereof and being connected with one actuator and the other actuator, respectively, and being conjointly movable with respect thereto in a direction therealong; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward movement of the joy stick to produce angular movements of the third and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 8

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movment of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions from connections with one another, said unit further comprising first and second take-off leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit to enable forward movement and rearward movement of the joy stick to produce movement in one direction and in the opposite direction of the first and second take-off leads with respect to the first and second resistances; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced ends and being in parallel with connections between their adjacent ends and between their remote ends, the first and second takeoff leads being connected to the adjacent ends and to the remote ends, respectively, of the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the connection between the adjacent ends thereof and being connected with one actuator and the other actuator, respectively, and being conjointly movable with respect thereto in a direction therealong; and d. means connecting the joy stick with the steering unit to enable rightward movement and leftward movement of the joy stick to produce angular movements of the third and fourth resistances with respect to the third and fourth takeoff leads in one direction and in the opposite direction, respectively.

Claim 9

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms, and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected across a source of power in parallel with one another with two connections at their ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being movable therealong; b. means Connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between one of the said two connections and the first takeoff lead and to decrease the portion of the second resistance between the said one connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between one of the said one connection and the first takeoff lead and to increase the portion of the second resistance between the said one connection and the second takeoff lead; c. a steering unit comprising third and fourth electrical resistances connected in parallel with one another with two connections at their ends, the first takeoff line and the second takeoff line, respectively, being connected to one connection and the other connection between the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and being connected with one actuator and the other actuator, respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement of the joy stick to decrease the portion of the third resistance between one of the last mentioned connections and the third takeoff lead without affecting the portion of the fourth resistance between said one connection and the fourth takeoff lead and leftward movement of the joy stick to decrease the portion of the fourth resistance between said one connection and the fourth takeoff lead without affecting the portion of the third resistance between said one connection and the fourth takeoff lead.

Claim 10

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms, and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected across a source of power in parallel with one another with two connections at their ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being movable therealong; b. means Connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between one of the said two connections and the first takeoff lead and to decrease the portion of the second resistance between the said one connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between one of the said one connection and the first takeoff lead and to increase the portion of the second resistance between the said one connection and the second takeoff lead; c. a steering unit comprising third and fourth electrical resistances connected in parallel with one another with two connections at their ends, the first takeoff line and the second takeoff line, respectively, being connected to one connection and the other connection between the third and fourth resistances, the steering unit further comprising third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and being connected with one actuator and the other actuator, respectively; and d. means connecting the joy stick with the steering unit to enable rightward movement of the joy stick to decrease the portion of the third resistance between one of the last mentioned connections and the third takeoff lead without affecting the portion of the fourth resistance between said one connection and the fourth takeoff lead and leftward movement of the joy stick to decrease the portion of the fourth resistance between said one connection and the fourth takeoff lead without affecting the portion of the third resistance between said one connection and the fourth takeoff lead.

Claim 11

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistance connected across a source of power in parallel with one another with two connections at their ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being movable therealong; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between one of the said two connections and the first takeoff lead to decrease the portion of the second resistance between the said one connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between one of the said one connection and the first takeoff lead and to increase the portion of the second resistance between the said one connection and the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and tHe second takeoff line, respectively, being connected to the conductor and to the remote ends of the third and foruth resistances; and d. means connecting the joy stick with the steering unit to enable rightward movement of the joy stick to decrease the portion of the third resistance between the remote end thereof and the third takeoff lead and the fourth takeoff lead to move along the conductor toward the third resistance and leftward movement of the joy stick to decrease the portion of the fourth resistance between the remote end thereof and the fourth takeoff lead and third takeoff lead to move along the conductor toward the fourth resistance.

Claim 12

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistance connected across a source of power in parallel with one another with two connections at their ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being movable therealong; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between one of the said two connections and the first takeoff lead to decrease the portion of the second resistance between the said one connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between one of the said one connection and the first takeoff lead and to increase the portion of the second resistance between the said one connection and the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and tHe second takeoff line, respectively, being connected to the conductor and to the remote ends of the third and foruth resistances; and d. means connecting the joy stick with the steering unit to enable rightward movement of the joy stick to decrease the portion of the third resistance between the remote end thereof and the third takeoff lead and the fourth takeoff lead to move along the conductor toward the third resistance and leftward movement of the joy stick to decrease the portion of the fourth resistance between the remote end thereof and the fourth takeoff lead and third takeoff lead to move along the conductor toward the fourth resistance.

Claim 13

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions form one another, the resistance having a first connection between their adjacent ends and a second connection between their remote ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between the first connection and the first takeoff lead and to decrease the portion of the second resistance between the first connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between the first connection and the first takeoff lead and to increase the portion of the second resistance between the first connection and the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and the second takeoff line, respectively, being connected to the conductor and to the remote neds of the third and fourth resistances; and d. means connecting the joy stick with the steering unit to enable leftward movement of the joy stick to swing the third and fourth takeoff leads angularly in one direction with respect to the third and fourth resistances and the conductor and thus to decrease the portion of the third resistance between the remote end thereof and the third takeoff lead by movement of the latter along the third resistance toward the remote end thereof while operating without effect on the fourth resistance by moving the fourth takeoff lead along the conductor toward the third resistance and rightward movement of the joy stick to swing the third and fourth takeoff leads angularly in the opposite direction with respect to the third and fourth resistances and the conductor and thus to decrease the portion of the fourth resistance between the remote end thereof and the fourth takeoff lead By movement of the latter along the fourth resistance toward the remote end thereof while operating without effect on the third resistance by moving the third takeoff lead along the conductor toward the fourth resistance.

Claim 14

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages produced by the occurrence of the desired speeds of the drive mechanisms; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a source of power and extending generally straight in opposite directions form one another, the resistance having a first connection between their adjacent ends and a second connection between their remote ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between the first connection and the first takeoff lead and to decrease the portion of the second resistance between the first connection and the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between the first connection and the first takeoff lead and to increase the portion of the second resistance between the first connection and the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and the second takeoff line, respectively, being connected to the conductor and to the remote neds of the third and fourth resistances; and d. means connecting the joy stick with the steering unit to enable leftward movement of the joy stick to swing the third and fourth takeoff leads angularly in one direction with respect to the third and fourth resistances and the conductor and thus to decrease the portion of the third resistance between the remote end thereof and the third takeoff lead by movement of the latter along the third resistance toward the remote end thereof while operating without effect on the fourth resistance by moving the fourth takeoff lead along the conductor toward the third resistance and rightward movement of the joy stick to swing the third and fourth takeoff leads angularly in the opposite direction with respect to the third and fourth resistances and the conductor and thus to decrease the portion of the fourth resistance between the remote end thereof and the fourth takeoff lead By movement of the latter along the fourth resistance toward the remote end thereof while operating without effect on the third resistance by moving the third takeoff lead along the conductor toward the fourth resistance.

Claim 15

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanism; each actuator is subject to ground or zero feed-back voltage when the associated drive mechanism is stopped; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a grounded source of power, a first connection between ends of the first and second resistances being at a positive voltage with respect to ground, a second connection between the other ends of the first and second resistances being at a negative voltage with respect to ground, the first and second resistances extending generally in opposite directions from adjacent ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being conjointly movable therealong; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between the first connection and the first takeoff lead and to decrease the portion of the second resistance between the second connection and the second takeoff lead for providing a positive voltage at the first takeoff lead and a negative voltage at the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between the first connection and the first takeoff lead and to increase the portion of the second resistance between the second connection and the second takeoff lead for providing a negative voltage at the first takeoff lead and a positive voltage at the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends of the third and fourth resistances, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and the second takeoff line, respectively, being connected to the conductor and to the remote ends of the third and fourth resistances; and d. means connecting the joy stick with the steering unit to enable leftward movement of the joy stick to swing the third and fourth takeoff leads angularly in one direction with respect to the third and fourth resistances and the conductor and thus to switch the sign of the voltage applied to the third takeoff lead by movement of the latter along the third resistance toward the remote end thereof while maintaining the quantity and sign of the voltage applied to the fourth takeoff lead by moving the fourth takeoff lead along the conductor toward the third resistance and rightward movement of the joy stick to swing the third and fourth takeoff leads angularly in the opposite direction with resPect to the third and fourth resistances and the conductor and thus to switch the sign of the voltage applied to the fourth takeoff lead by movement of the latter along the fourth resistance toward the remote end threof while maintaining the quantity and sign of the voltage applied to the third takeoff lead by moving the third takeoff lead along the conductor toward the fourth resistance.

Claim 16

In a vehicle in which two drive mechanisms are driven at the same speed in a given direction for straight forward movement of the vehicle, at the same speed in the opposite direction for straight rearward movement of the vehicle, and in opposite directions or at different speeds in the same direction for steering of the vehicle; two actuators control the direction of drive of the drive mechanisms by the sign of the voltages impressed across the actuators and the speeds of the drive mechanisms by the amount of impressed voltages and the balancing out thereof by equal feed-back voltages produced by the occurrence of the desired speeds of the drive mechanism; each actuator is subject to ground or zero feed-back voltage when the associated drive mechanism is stopped; and a joy stick is moved forwardly and rearwardly for forward and rearward movement of the vehicle and to the right and to the left for turning of the vehicle; the combination with the actuators and the joy stick, of a. a direction unit comprising first and second electrical resistances connected in parallel across a grounded source of power, a first connection between ends of the first and second resistances being at a positive voltage with respect to ground, a second connection between the other ends of the first and second resistances being at a negative voltage with respect to ground, the first and second resistances extending generally in opposite directions from adjacent ends, the direction unit further comprising first and second takeoff leads contacting the first resistance and the second resistance, respectively, and being conjointly movable therealong; b. means connecting the joy stick with the direction unit so as to enable forward movement of the joy stick to increase the portion of the first resistance between the first connection and the first takeoff lead and to decrease the portion of the second resistance between the second connection and the second takeoff lead for providing a positive voltage at the first takeoff lead and a negative voltage at the second takeoff lead and rearward movement of the joy stick to decrease the portion of the first resistance between the first connection and the first takeoff lead and to increase the portion of the second resistance between the second connection and the second takeoff lead for providing a negative voltage at the first takeoff lead and a positive voltage at the second takeoff lead; c. a steering unit comprising third and fourth resistances extending generally arcuately in opposite directions from adjacent spaced ends to remote spaced connected ends, a generally arcuate conductor of appreciable length connecting the adjacent spaced ends of the third and fourth resistances, and third and fourth takeoff leads contactable with the third and fourth resistances, respectively, and with the conductor and being connected with one actuator and the other actuator, respectively, the first takeoff line and the second takeoff line, respectively, being connected to the conductor and to the remote ends of the third and fourth resistances; and d. means connecting the joy stick with the steering unit to enable leftward movement of the joy stick to swing the third and fourth takeoff leads angularly in one direction with respect to the third and fourth resistances and the conductor and thus to switch the sign of the voltage applied to the third takeoff lead by movement of the latter along the third resistance toward the remote end thereof while maintaining the quantity and sign of the voltage applied to the fourth takeoff lead by moving the fourth takeoff lead along the conductor toward the third resistance and rightward movement of the joy stick to swing the third and fourth takeoff leads angularly in the opposite direction with resPect to the third and fourth resistances and the conductor and thus to switch the sign of the voltage applied to the fourth takeoff lead by movement of the latter along the fourth resistance toward the remote end threof while maintaining the quantity and sign of the voltage applied to the third takeoff lead by moving the third takeoff lead along the conductor toward the fourth resistance.

Claim 17

The combination specified in claim 8 and further comprising an anti-stall mechanism comprising a fifth resistance grounded at one end, a fifth takeoff lead movable therealong and forming therewith part of the second takeoff line, and means responsive to a decrease in pressure due to approach or occurrence of stalling of the engine for shifting the fifth resistance and takeoff lead with respect to one another so as relatively to move the fifth takeoff lead toward the grounded end of the fifth resistance.

Claim 18

The combination specified in claim 9 and further comprising means for assuring equal speeds of the two drive mechanisms when operated for straight forward movement or straight rearward movement of the vehicle, said means comprising sixth and seventh resistances extending generally in opposite directions from adjacent spaced ends to remote spaced grounded ends, a second conductor connecting the adjacent ends of the sixth and seventh resistances and being connected to the first takeoff lead, sixth and seventh takeoff leads contactable with the sixth and seventh resistances, respectively, and with the second conductor and connectable with the connections between the fourth and fifth takeoff leads and the two actuators, and means responsive to difference in speeds of the two drive mechanisms for shifting the sixth and seventh resistances and second conductor with respect to the sixth and seventh takeoff leads in one direction to decrease the portion of the sixth resistance between its grounded end and the sixth takeoff lead while operating without effect on the seventh resistance by relatively moving the seventh takeoff lead along the second conductor toward the sixth resistance and in the opposite direction to decrease the portion of the seventh resistance between its grounded end and the seventh takeoff lead while operating without effect on the sixth resistance by relatively moving the sixth takeoff lead along the second conductor toward the seventh resistance; the steering unit being disconnected from the direction unit by positioning of the joy stick between positions to the right and left for steering of the vehicle, the equalizer being taken out of operation by movement of the joy stick to the left or right for steering of the vehicle.