US 4,230,280 A · Vehicular spreader with digital electronic ground speed link

Abstract

In a system for spreading material from a vehicle, the ground speed of the vehicle is sensed by a low torque transducer which generates a train of electrical pulses or digital signal having a repetition rate representative of the vehicle's ground speed. The digital signal energizes a stepper motor. The shaft of the stepper motor is coupled to a mechanical comparator which is also responsive to the speed of a conveyor, which delivers the material to be spread, for controlling the conveyor drive motor so that the speed of the conveyor tracks the ground speed of the vehicle even at very low speeds. Proportioning of the ground speed signals is accomplished electronically by a digital counter circuit. Override of the ground speed control signal is actuated by the operator. The override may require continued operator actuation; or the override, once actuated may last for a predetermined time or a predetermined distance travelled by the vehicle. In the latter two cases, the time and distance may be adjusted.

Claims11

Dependent claims

In a control system for a vehicular spreader having a source of material to be spread, distribution means, delivery means for delivering material from said source to said distribution means and power means for actuating said delivery means, the improvement comprising:

low-torque transducer means sensing the ground speed of said vehicle for generating a train of electrical pulses having a repetition rate representative of the ground speed of said vehicle;
stepper motor means actuated by said train of electrical pulses;
comparator means responsive to the angular velocity of said stepper motor means and said power means for generating an error signal representative of the difference between the speed of said delivery means and the speed of said vehicle;
and control means responsive to said error signal for controlling the speed of said power means to track the speed of said vehicle.

1 more element

In a control system for a vehicular spreader including a source of material to be spread, distribution means for spreading said material;

power means for actuating said distribution means;
and delivery means for delivering material from said source to said distribution means, the improvement comprising:
digital transducer means responsive to the ground speed of said vehicle for generating a train of electrical pulses having a repetition rate representative of the speed of said vehicle;
digital motor means adjacent the rear end of said vehicle and responsive to said train of pulses for incrementally rotating an output shaft, said power means being responsive to the output shaft of said digital motor means for controlling the speed of said delivery means;
counter circuit means located in the cab of said vehicle and responsive to the output pulses from said transducer means for dividing said repetition rate by a predetermined amount;
said transducer means comprising a disc having alternate opaque and transparent sectors;
means for rotating said disc at an angular velocity representative of the speed of said vehicle;
photo couple means associated with said disc for generating pulses as said alternate opaque and transparent sectors of said disc pass a predetermined location;
logic and drive circuit means in said cab responsive to the output of said counter circuit means for generating digital power signals to control the rotational movement of said motor means;
and conductor means coupling the power signals from said logic and drive circuit means in said cab to said motor means, whereby said conductor means carries digital power signals having relative immunity to noise.

7 more elements

Dependencies are inferred from the claim text.

Vehicular spreader with digital electronic ground speed link

Life of this patent

Vehicular spreader with digital electronic ground speed link

Life of this patent

Abstract

Claims11