Abstract: A robotic floor cleaning device that features a controlled liquid releasing mechanism. A rotatable cylinder with at least one aperture for storing a limited quantity of liquid is connected to a non-propelling wheel of the robotic floor cleaning device. There is a passage below the cylinder and between the cylinder and a drainage mechanism. The cylinder is within or adjacent to a liquid reservoir. Each time an aperture is exposed to the liquid within the reservoir it fills with liquid. As the wheel turns the connected cylinder is rotated until the aperture is adjacent to the passage. The liquid in the aperture will flow through the passage and enter the drainage mechanism which disperses the liquid to the working surface. The release of liquid is halted when the connected wheel stops turning.

Abstract: A distributed pump system is disclosed. The distributed pump system comprises a supply source and a support structure arranged on or proximate an agricultural vehicle. At least two fluid distribution elements are mounted to the support structure and are coupled at an inlet to a first conduit to provide fluid communication between the fluid distribution elements and the supply source. An application system including at least two application units is coupled to one or more of the fluid distribution elements by a second conduit. A first monitoring device is associated with a respective application unit and fluid distribution element, and is configured to sense a downstream flow parameter of the second conduit and generate a corresponding output signal. An electronic control unit is communicatively coupled to each of the fluid distribution elements and is configured to dynamically adjust an input parameter of one or more of the fluid distribution elements.

Abstract: A thermoplastic extrusion vehicle for continuous processing of thermoplastic material used for applying lines and stripes to a roadway. Heated oil from a burner is directed to a common reservoir having a section for oil distributed to the extremities of the vehicle and a main section for heating of melting kettles; the common reservoir having a divider wall capable of maintaining two different temperatures within the reservoir. A programmable logic controller displays and records the mil thickness of lines that is calculated according to the volume of material consumed at the rate of application based upon the speed of the vehicle.

Abstract: An electro-hydraulic actuation system for a sprayer comprises a hydraulic system, a hydraulic actuator, an electric actuator and a sprayer. The hydraulic system is for pressurizing a hydraulic fluid. The hydraulic actuator is powered by the hydraulic system. The electric actuator controls actuation of the hydraulic actuator by the hydraulic system. The sprayer is actuated by the hydraulic actuator.

Abstract: Kits for sprayer vehicles may include electrically-actuatable solenoids configured to selectably turn individual nozzle assemblies on and off when installed in ports from which check valves were removed, one or more wirelessly-controllable solenoid controllers, a first wiring harness to electrically connect the electrically-actuatable solenoids to the controller(s), a GPS antenna system that wirelessly communicates information identifying its position, bracketry configured to attach the GPS antenna system and the one or more controllers with the sprayer vehicle, a second wiring harness to electrically connect the controller(s) and the GPS antenna system with a source of electrical power on the vehicle, and a mobile device configured to wirelessly cause the one or more controllers to turn individual nozzle assemblies on and off based on a comparison of predetermined geographical boundaries and predefined relative positions of the individual nozzle assemblies to real-time location information received wirelessl

Abstract: An agricultural trailed implement includes a chassis with tongue for hitching to a tractor. A housing is integrated into a loadbearing section of the tongue. A pump or generator is mounted inside the housing and is driven by a PTO shaft connected to an attached tractor. The pump housing may define a sump which provides a fluid reservoir to supply the pump in a hydraulic circuit.

Abstract: Systems and methods for controlling fluid delivery on a site using at least one fluid delivery machine are disclosed. An exemplary such method includes identifying at least one path on the site based on map information associated with the site, calculating a fluid delivery requirement of the at least one path based on environmental information associated with the site, and dispatching a fluid delivery machine on a mission to treat the at least one path with fluid based on the fluid delivery requirement.

Abstract: The device according to the invention comprises a bar that includes several consecutive ducts with at least one inlet connected to a source of the liquid product and outlets communicating with nozzles. The device further comprises several sensors for measuring a physical property making it possible to determine a pressure difference between ducts or a pressure in one respective duct, several members designed to vary the pressures inside respective ducts, as well as at least one control unit estimating the pressure differences between ducts and driving the members to reduce those pressure differences or equalize those pressures. This device thus limits the pressure differences, and therefore flow differences, of the liquid product between the nozzles, in particular between the ends of very long bars moving over significant bankings.

Abstract: A method of controlling a fluid delivery machine configured to deliver fluid on a worksite is disclosed. In the method, operation of a power source of the fluid delivery machine is controlled with a control module. Fluid delivery on the worksite is also controlled by the control module.

Abstract: This document discusses, among other things, apparatus and methods for a multi-section applicator having variable-rate sections. In an example, an apparatus can include at least one distribution manifold, a user interface, and an applicator controller. The at least one distribution manifold distributes a substance and can include an inlet port configured to receive the substance, a plurality of outlet ports, one or more sensors located at an outlet port, a controllable valve that supplies the substance to the inlet port. The applicator controller measures a value of the distribution parameter using the sensor signal produced by the at least one sensor of an outlet port, detects when the measured value differs from a specified target value by more than a specified error threshold value, and presents an indication, using the user interface, that the measured value differs from the target value according to the detection.

Abstract: A fluid distribution system and method for mobile applications. The system includes a power source, a pump driven by the power source, and a motor driven by the pump. The system also includes a spray head with a fluid inlet passage, a fluid outlet passage, a fluid piston disposed in a chamber for controlled access between the inlet and outlet passages and defining a variable orifice, and a hydraulic cylinder controllably engaged to the orifice. The fluid piston and the hydraulic cylinder are aligned with a common longitudinal axis, and the inlet passage is offset from the axis in a direction opposed to the location of the outlet passage.

Abstract: A fluid distribution system and method for mobile applications. The system includes a power source, a pump driven by the power source, and a motor driven by the pump. The system also includes a spray head with a fluid inlet passage, a fluid outlet passage, a fluid piston disposed in a chamber for controlled access between the inlet and outlet passages and defining a variable orifice, and a hydraulic cylinder controllably engaged to the orifice. The fluid piston and the hydraulic cylinder are aligned with a common longitudinal axis, and the inlet passage is offset from the axis in a direction opposed to the location of the outlet passage.

Abstract: An apparatus to aid in the layout of hashed lines, particularly for laying out lines in parking lots near parking islands and handicapped parking spots is herein disclosed, comprising a large push broom on wheels. Two (2) canisters of marking chalk project downward from a main horizontal member and are spaced so as to produce parallel chalk lines or chalk dots within no parking areas in a parking lot. A guide arm is located on a side of the apparatus such that it can trace the last set of dots and produce two (2) more in an offset, but equally-spaced manner.

Abstract: An agricultural field sprayer (10) includes an electrically driven pump (50) locatable directly under sprayer fluid tank for conveying the fluid from the tank to a supply line. A return line (54) connects the pump (50) to the tank (22), and a sprayer line (32) connecting the pump (50) to an application assembly (20). The return line (54) and the sprayer line (32) include electrically operated control valves (68, 64), and an electronic control system (56) operates the motor (46) and the control valves (64, 68) as a function of different variables including field sprayer speed and sprayer fluid characteristics. The valve and motor controls and an additional valve-controlled return line facilitate numerous operational modes including tank fill, rinse, recirculation, spray, partial width spray, and stop modes.

Abstract: A self-propelled and self-contained shrouded walking boom unit including a small tank and pump mounted on the unit. The unit also has a small transmission and DC drive which makes the unit self-propelled. The configuration is such that the operator walks in front of the spray applicator system with the spray being applied behind the operator. The operator steers the applicator and controls the spray from a handle attached to a single front steering wheel.

Abstract: A device carried on a moving vehicle for creating marking lines, which are a plurality of elements and are made of a highly viscous marking material, on a surface that is to be marked. The device includes a housing formed by walls and a discharge slot formed in at least one of the walls of the housing and extending transversely to a direction of movement of the vehicle, the discharge slot being limited in extent by a front discharge slot edge and a rear discharge slot edge, seen in the direction of movement of the vehicle. A pressurized material supply line leads to an interior of the housing. A rotatable hollow cylinder formed of a jacket is located in the interior of the housing and is arranged to rotate with the movement of the vehicle carrying the device. The cylinder is provided with a plurality of passages through the jacket, which, depending on a rotary position of the cylinder, establish a connection between the pressurized material supply line and the discharge slot.

Abstract: A crop sprayer axle assembly includes a differential output shaft extending from a differential and coupled to a transfer drive shaft. The transfer drive extends downwardly from the differential output shaft and in a lengthwise direction with respect to the crop sprayer where it is operably connected to a wheel drive shaft.

Abstract: A method of applying a chemical material, such as a pesticide, to a surface utilizes a wheel mounted spraying assembly. The wheel mounted spraying assembly includes: a rod having a wheel rotatably mounted on its lower end portion for supporting the spraying assembly on a generally horizontal surface and enabling the spraying assembly to be moved over the surface; a spray nozzle mounted on the spraying assembly adjacent the wheel; a supply line for supplying a chemical material under pressure to the spray nozzle; and a control for controlling the flow of the chemical material to and through the spray nozzle. The spray nozzle is oriented to spray the chemical material in an expanding pattern in an outward direction to one side of the lower portion of the spraying assembly to apply the chemical material to a generally vertical and/or generally horizontal surface.

Abstract: A method of applying substances to a land begins with inputting data indicative of the substance requirement for the land into a processor. The land is traversed with a vehicle having an engine and a transmission that can vary the vehicle speed without adjusting the engine speed. The vehicle has an appliance including a mechanism for applying the substance to the land. The appliance application rate is input into the processor with the desired engine speed. The land is traversed with the vehicle with the engine speed set at the desired engine speed. The vehicle position is established, and a signal is generated to indicate a requirement for adjustment to the transmission to change the vehicle speed to match the individual section requirement to the appliance application rate. Lastly, the transmission is adjusted according to the signal generated by the processor.

Abstract: A system for the variable rate application of pesticides is provides, comprising a) a vehicle capable of traversing an agricultural production area; b) at least one sensor for attachment to said vehicle for direct sensing plant and/or condition data on said agricultural production area, said sensor being capable of transmitting said directly sensed data to computing means; c) computing means for processing the data output of said sensor; d) at least one tank mounted on or attached to said vehicle carrying pesticidal formulations; e) pesticide delivery means mounted on or attached to said vehicle capable of receiving delivery instructions from said computing means and of delivering pesticides from said tank in compliance with said instructions; characterized in that f) said computing means is capable of reading and processing data from a computer-readable medium having stored thereon a plurality of data, said plurality of data including data relating to the functional relationship between the amounts of indivi

Abstract: An automatic wind-drift compensation system is provided for an agricultural sprayer. The system includes a control unit adapted to receive input data including wind speed and direction, vehicle speed and direction, and desired spray overlap. The control unit is programmed with a set of instructions for processing the data and generating output data. The output data facilitates steering of the sprayer through the field to achieve the desired spray overlap.

Abstract: A children's ride-on vehicle that resembles a riding lawnmower or tractor. The vehicle includes a drive assembly with a battery-powered motor, and a frame that is adapted to support a child. The ride-on further includes a bubble-producing mechanism adapted to produce a stream of bubbles.

Abstract: A children's ride-on vehicle that resembles a riding lawnmower or tractor. Th vehicle includes a drive assembly with a battery-powered motor, and a frame that is adapted to support a child. The ride-on further includes a bubble-producing mechanism adapted to produce a stream of bubbles, such as to simulate the stream of clippings discharged by a full-size mower or tractor.

Abstract: A method for driving the emptying of an induction unit with which an agricultural sprayer is equipped. The emptying is driven by a user acting with at least one of his lower limbs on a drive element. An agricultural sprayer for implementing such a method, comprising a drive element which has just one stable position.

Abstract: A comprehesive product dispensing system including a product/carrier dispensing system. The product carrier dispensing system comprising a carrier dispensing system and a product dispensing system. The product dispensing system including a product dispensing device and a product dispensing control system. The product dispensing control system includes a flowmeter and a controller. The controller regulates the injection rate of product injected into the carrier and the flowmeter provides feedback to the controller for regulating the injection rate of product. Product is dispensed from product containers which may be filled via a closed transfer delivery system for safe product handling and transfer.

Abstract: A vehicle-mounted emulsion dispersing device including a dispersing nozzle that is opened and closed by an opening/closing device, an emulsion tank that stores emulsion, and an emulsion pump for pumping emulsion from the tank to the nozzle and spraying the emulsion from the nozzle. A control device controls the emulsion pump and the dispersing nozzle so that the rate of emulsion dispersion coincides with a set value. A method of dispersing emulsion using the emulsion dispersing device wherein the control device intermittently disperses the emulsion by intermittently opening and closing the opening/closing device so that the area of dispersed emulsion is continuous from front to back.

Abstract: An apparatus of spreading a fluid on the floor includes four rectangular application rotating bodies partially overlapping each other, and four nozzles supplying the fluid provided in rotation areas of the respective application rotating bodies. The rotation position of the application rotating body is detected by a light shielding plate and a photosensor. A control portion controls each component so that the fluid is applied onto the floor from a tank through the nozzle by a pump when the application rotating body is not directly under the nozzle. As a result, the apparatus of spreading a fluid on the floor capable of optimally controlling the quantity of the fluid to be applied according to the application condition can be provided.

Abstract: A straight row seed planter wherein a support frame mounts a hopper onto a support beam, with an axle rotatably mounted within the support frame parallel to the support beam, wherein the support beam includes at least one pair of feed cones extending therefrom, with each feed cone having a closure door plate, and each closure door plate arranged for sequential operation by a respective cam member that effects sequential opening of each respective door plate to effect sequential feeding from the respective feed cones. The hopper is arranged for selective securement to the support frame to accommodate various quantities and sizing of seed to be planted.

Abstract: A liquid distributor having a pair of variable displacement pumps driven by a single electric motor, the rotation speed of which is determined by a voltage from a controller in response to a predetermined ground speed and application rate which mixes a chemical with water in a desired proportion and delivers a solution to be directed into an open furrow just prior to the furrow being covered with dirt.

Abstract: A system for controlling the flow of agricultural ammonia from a tank to applicator apparatus transported by a land vehicle over the ground includes a ground speed sensor that generates a speed signal representing the speed of the land vehicle over the ground, an ammonia flow reader that generates a flow rate signal representing the flow of ammonia through the system, a throttling device having means for varying the flow of ammonia through the system, and i)computing means for sending a throttling signal to the throttling device, the computing means being responsive to the speed signal and flow rate signal to cause the throttling device to throttle the flow of ammonia through the system.

Abstract: A pressure control system, including a pilot valve suitable for use therein, for providing a constant pressure from a non-compensated pump to a plurality of nozzle valves controlling flow from a manifold to nozzles associated with the valves, including a pressure control valve interposed between the pump and the manifold which is response to a control pressure created by a pilot valve which reduces manifold pressure to the control pressure.

Abstract: The apparatus comprises at least one pesticide container (16), and a dosage pump (18) for the container or the containers, respectively, or for each container this pump or each of the existing pumps comprising a step motor controlled precision pump of the radial type which is connected via a pressure and check valve (21) to a mixing chamber (22) to be connected to one or more nozzle ramps (14) and having an inlet for water, to which the pesticide is to be added. The dose control apparatus also comprises a control unit (35) for adjusting the pump flow or the pump flows, respectively, in dependence on definite parameters, the driving speed being one.

Abstract: A method and apparatus for dispensing a substance to a work area in which the method includes the steps of determining the quantity of the substance to be dispensed substantially evenly to the work area, calculating the rate of dispensing the substance to the work area for the quantity determined in the determining step to achieve substantially even dispensing, dispensing the substance to the work area at the calculated rate during movement over the work area, and adjusting the rate of dispensing at intervals during such movement to minimize error in such dispensing.

Abstract: A self-contained, hand-operated, compact applicator for dispensing liquid and/or dry lawn care products is disclosed in which dry treatment materials are broadcast from a hopper in response to manual propulsion of the applicator over the terrain and liquid materials, stored in a tank carried by the hopper, are pressurized by electrically powered pump means and dispensed via plural valve operated spray nozzles selectively controlled by the operator to effect regulated and uniform application of dry and liquid treatment materials either contemporaneously or independently of one another.

Abstract: A windshield washer control for a vehicle is responsive to vehicle speed to vary the speed of an electric motor driven pump so as to vary the pump pressure with vehicle speed and thus counteract the downward dislocating effect, increasing with vehicle speed, of air rushing over the windshield, whereby the cleaning fluid is applied to a predetermined target area of the windshield regardless of varying vehicle speed. In addition, the pump may be activated for a time varying inversely with vehicle speed to counteract the variation of volume flow with varying pump pressure and thus cause a substantially constant volume of cleaning fluid to be applied to the windshield for each activation of the pump.

Abstract: A fluid delivery system (10) is provided for delivering at least one chemical (26) onto a field in a desired concentration. A carrier fluid (67) is provided for diluting the farm chemical (26). The mixture is pumped through a spray boom (18) onto the field by a main fluid pump (74). The chemical (26) is delivered to the inlet port (76) of the main fluid pump (74) by a chemical pump (54). The chemical pump (54) is operated by a variable speed stepping motor (56). The speed of the stepping motor (56) is controlled by a speed sensing wheel (88) to provide a uniform concentration of chemical on the field independent of vehicle speed. The motor speed is also controlled by a thumbwheel switch (116) to deliver a desired concentration on the field compensating for drive vehicle wheel slippage. The motor speed is also adjusted to calibrate the delivery concentration to the nozzle pattern through calibration switches.

Abstract: A material-spreading field vehicle has a large hopper for holding comminuted plant nutrients, a conveyor for feeding nutrients to an evenly spreading distributor, and a plurality of relatively small always-carried auxiliary containers for holding concentrated water-solutions and/or suspensions of herbicides, insecticides, hormones and other soil-treating chemicals. The apparatus includes vehicle-speed-responsive mechanism for insuring uniform mixture of the solid and liquid materials prior to spreading, by the use of positive-action pumps for each liquid feed line to insure accurate metering of each liquid to the conveyor which leads to a conventional mixer upstream from the distributor. Each pump is driven from the vehicle-speed-responsive mechanism by a variable-ratio speed-changer for metering the several materials being combined. A manually controllable device may be employed to vary the mixed-material-dispensing rate as desired.

Abstract: An improved control system for a mobile material distribution apparatus of the type having a ground speed sensor, a distributing device for spreading material along the path of travel of the apparatus, a variable rate delivery structure for delivering material to the distributing structure and a delivery rate sensor. The control system comprises a calculating circuit responsive to signals developed by the ground speed sensor and delivery rate sensor and to a signal corresponding to a desired distribution rate of material for periodically calculating the difference between the desired delivery rate and the actual delivery rate and developing a difference signal. A control signal is developed in response to each difference signal for varying the delivery rate of material to the distributing structure as necessary to achieve the desired material delivery rate.

Abstract: A vehicle mounted liquid spreading device adapted to deliver selected, essentially constant, volumes of liquid per unit area over a range of vehicle speeds. The device operates to adjust the pressure in the liquid distribution system as a function of vehicle speed by comparing the pressure in the distribution system to a pressure proportional to the vehicle speed and utilizing a signal so obtained to control a liquid by-pass valve.

Abstract: A mobile wheel mounted spreader apparatus has a material feed conveyor and a broadcast spreading impeller fan. A wheel driven drive train operates through a gear reducer to drive the conveyor at a speed proportional to the towed speed of the spreader apparatus and operates through a hydraulic system, to drive the impeller fan at a constant speed regardless of variations in the towed speed of the spreader apparatus.

Abstract: A vehicle-mounted spreading apparatus includes a container for the material to be spread, at least one spreading disc rotatable about a vertical axis and a dosing device for conveying material from the container to the spreading disc as the vehicle moves along the ground. The disc and the dosing device are powered from a driving wheel which can be lowered into driving contact with the ground. The driving wheel conveys power to a mechanical power transfer assembly which drives the dosing device and which drives an adjustable speed motor system for the spreading disc.

Abstract: Apparatus for controlling the delivery of material from a moving vehicle using a "closed loop" feedback control. The error signal to close the loop is derived from a continuous measurement of the actual rate of mass flow of material compared to the desired or computed rate of mass flow for a range of vehicle speeds. The vehicle speed is measured and used to modify the desired rate of mass flow in order to achieve a controlled mass per unit area of ground surface.

Abstract: This invention relates to lawn spreader markers generally, and more specifically to an intermittent manually controlled marking apparatus which delineates the area covered by the spreader hopper opening and which utilizes foam as the marking material.

Abstract: An automatic volume control system for controlling the rate at which fluid, such as paint, is sprayed from spray guns on a mobile vehicle as a function of vehicle speed. The device permits paint lines to be maintained at a uniform thickness independently of the vehicle speed. A tachometer generator generates a voltage proportional to the vehicle road speed which voltage controls the opening of an adjustable hydraulic valve. Hydraulic fluid passing through the hydraulic valve drives a hydraulic generator which in turn drives a spray gun system. The voltage from the tachometer generator thereby causes the hydraulic fluid to drive the hydraulic motor and paint pump at a rate which is proportional to the vehicle road speed. The hydraulic fluid is suitably pumped through the hydraulic valve to the hydraulic motor by a hydraulic pump driven by the power take-off of the vehicle.

Abstract: A trailer-type vehicle for transporting and dispensing solid materials over the ground includes a self-contained, hydraulic power and control system driven by one of the vehicle's ground engaging wheels which operates a first dispensing mechanism at a selectable speed proportional to the vehicle's rate of travel over the ground, but operates a second dispensing mechanism at a constant speed regardless of the vehicle's rate of travel. A single hydraulic motor driven by a selectively engageable drive train connected with one of the vehicle's wheels is novelly employed as a hydraulic pump for delivering a force transmitting fluid through a pair of control valves to a pair of hydraulic motors respectively powering the dispensing mechanisms. One of the control valves includes provision for selectively adjusting the flow rate to the associated hydraulic motor thereby allowing adjustment of the volume of material being dispensed per area of ground covered by the vehicle.

Abstract: The invention relates to a mobile liquid distributing apparatus comprising a quasi-constant flow supply device a variable flow distributing device, and liquid transfer means interconnecting the two devices. A flow regulating means is included in the transfer means and a regulation device acts on the regulating means and comprises comparison means. The latter receive, on one hand, a signal from means for measuring a magnitude which is a characteristic of the flow of the liquid in the transfer means and, on the other hand, a reference signal from means for measuring the speed of the apparatus through means for transforming between the speed and said magnitude. The means measuring the characteristic magnitude is constituted by a flow measuring means and the transforming means are constituted by means for applying a coefficient of proportionality. The invention is of particular interest in applications in the agricultural field.

Abstract: Mobile apparatus for spreading a constant volume of liquid per unit area of surface in spite of variations in speed of travel, has a spreading liquid circuit which includes a pressure regulator for controlling the liquid pressure in response to the pressure in an auxiliary liquid circuit. The pressure in the auxiliary liquid circuit is controlled by a sensing wheel which is carried on a pivotally mounted arm so that the sensing wheel can engage either with a wheel of the vehicle on which the apparatus is mounted or with the ground. The sensing wheel provides a pump for the auxiliary circuit and the flow rate of the pump is controlled by an orifice which can be partially occluded by a cam-like shutter.

Abstract: A spreader application monitoring device to determine and display the volume of liquid or granular material applied per unit area of ground by mobile application equipment is described. The device includes a first measuring means which generates an area electrical pulse signal having a frequency proportional to the rate at which the application equipment covers i.e., traverses a unit of area, and a second measuring means which generates a volume electrical pulse signal having a frequency proportional to the rate of application of the material. A frequency multiplying means operates on the electrical pulses of the second measuring means, a pulse counting means being connected to the output of the frequency multiplying means and the first measuring means for accumulating the electrical pulses from the frequency multiplying means for a period of time determined by the first measuring means and corresponding to the time required by said application equipment to cover a unit of area.

Abstract: A mobile agricultural sprayer having a control system for controlling the amount of chemical additive added to a water stream from a mobile storage tank in response to a chemical additive concentration detector is disclosed. The mobile sprayer utilizes a mobile water storage tank and at least one chemical additive tank which communicates with the water to be sprayed at a point between the tank and the sprinkler heads. A pump draws water from the storage tank and directs it under pressure to the sprinkler heads. The chemical additive is typically added in liquid form, such as a solution or a slurry, at a point preferably upstream of the pump inlet while concentration is measured at a point between the point of addition of the chemicals and the sprinkler heads and preferably before the inlet of the pump. The concentration detector transmits information to a monitor which controls the amount of chemical introduced into the water to be sprayed.

Abstract: A device for determining the volume of spraying liquid applied to unit area of ground by spraying equipment. The device includes pulse generators for generating first and second electrical signals respectively representing the rate of supply of liquid and the ground speed of the equipment. A function generating unit receives the two signals and, responding to these signals, produces an output signal representing the product of the ratio between the signals and a predetermined factor. The output signal from the comparator is applied to a meter which provides a visual indication of the output signal, this representing the volume of liquid applied to unit area of the ground. An automatic speed control unit can be coupled to an output from the function generating unit or to the means for generating the second electrical signal. This unit is actuated by an operator when the visual indicator indicates that a predetermined supply of liquid to unit area has been achieved.