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.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    U.S. Provisional Application for Patent No. 60/901,938 filed Feb. 16, 2007, with title “Self-Propelled Walking Spray Boom” which is hereby incorporated by reference. Applicant claims priority pursuant to 35 U.S.C. Par. 119(e)(i). 
     
    
     STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    This invention relates to a device used to apply liquids to surfaces such as lawns. 
         [0005]    2. Brief Description of Prior Art 
         [0006]    It has been conventional practice to spray liquids to fertilize and protect outdoor plants such as lawns and gardens. There has long been problems with spraying chemicals, problems including over-application, runoff, the wind carrying overspray and the exposure of workers and surrounding surfaces to the overspray and also to workers tracking through chemicals. 
         [0007]      FIG. 1  shows a prior art spray applicator  100 . In the prior art spray applicators  100  were walked behind and included a hose  102  that had to be attached to a source of pressurized liquid. This tethered the device making it more difficult to use. Also, the operator had to walk through the applied liquid, also the wheels and hose traveled through the applied chemical which was very undesirable. Also, since the user powers the unit, the ground speed is not constant, which leads to an inconsistent application of liquid. The prior art also often requires multiple operators, one to walk the applicator and others at the source of fluid for the hose  102 . Another problem with the prior art is that the chemicals flow through a fitting in the handle so leaks are a dangerous problem for the operator. 
         [0008]    As will be described, the preferred embodiments of the present invention overcome disadvantages of the prior art. 
       SUMMARY OF THE INVENTION 
       [0009]    A self-contained walk ahead spray applicator including a drive wheel, a motor driving the drive wheel and a handle to a steering wheel such that rotation of the handle controls the direction of travel of the spray applicator. A battery powers the motor and a pump. The spray applicator includes a tank containing liquid, the pump pumping liquid from the tank to a nozzle under a protective shroud, wherein the drive wheel drives the spray applicator such that the handle leads the nozzle and wherein the steering wheel is ahead of the drive wheels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a prior art spray applicator. 
           [0011]      FIG. 2  shows a preferred embodiment of the present invention, a walk ahead spray applicator. 
           [0012]      FIG. 3  shows detail of the spray applicator of  FIG. 2 . 
           [0013]      FIG. 4  shows additional details of the spray applicator of  FIG. 2 . 
           [0014]      FIG. 5  shows a partial cross-sectional view of the spray applicator of  FIG. 2 . 
           [0015]      FIG. 6  shows further details of the spray applicator of  FIG. 2 . 
       
    
    
       [0016]    The present invention will be illustrated on the basis of the figures and following description of a preferred embodiment thereof. 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    In accordance with the present invention, a spray applicator is disclosed. The spray applicator is directed to a self-propelled walking spray boom for applying liquids to surfaces such as lawns. Specifically, it will be noted in the drawings that the configuration of the self-propelled walking spray boom of the present invention is such that the operator walks in front of the spray applicator system with the spray being applied behind the operator. In the broadest context, the self-propelled walking spray boom consists of components configured and correlated with respect to each other so as to attain the desired objective. 
         [0018]      FIG. 2  illustrates a preferred embodiment of a spray applicator  200  made in accordance with the present invention. The spray applicator  200  includes a control such as an elongated handle  202 . The handle  202  includes a grip  204 , a spray control  206 , and a throttle control  208 . The handle  202  is connected to a pivot axle  210  that carries a steering wheel  212  such that said handle  202  and said steering wheel  212  rotate about a common axis. 
         [0019]    The spray applicator  200  includes two (2) drive wheels  216  and a tank  220  that can contain liquids to be applied such as liquid fertilizer or herbicide, for example. The tank  220  includes a removable lid  222  to allow it to be filled, and the tank  220  can include an agitator. The tank  220  further includes a non-spill quick coupling system such that a nipple  224  installed on the tank  220  mates with a coupling (not shown) attached to an external hose for delivering liquids to the tank  220 . The non-spill attachment as described provides an easy, safe method of filling the tank  220  without removing the lid  222  and eliminates exposing the operator to hazardous liquids during transfer. 
         [0020]    The spray applicator  200  can include batteries  228  that can provide power for electric motors to drive the wheels  216  and to pressurize the tank  220 . Any power source could be used to power the spray applicator  200 . 
         [0021]    The spray applicator  200  further includes a shroud  230  that prevents wind from blowing chemicals as they are applied. The shroud  230  includes a guide wheel  232  that prevent the ends of the boom and shroud  230  from digging into unlevel ground. The shroud  230  also includes windows  234  that allows an operator to observe the application of liquid. An electric motor and transmission can apply power directly to a drive wheel  216  or any drive arrangement can be used. A frame  244  connects the shroud  230  to the spray applicator  200 . 
         [0022]      FIG. 3  shows further details of the spray applicator  200 . The handle  202  is pinned  300  to the pivot axle  210 . The pivot axle  210  is mounted in bushings  302  connected to the frame  244 . Rotation of the handle  202  about the axle  210  will cause the steering wheel  212  to turn allowing the user to steer the spray applicator  200 . The handle  202  carries an adjustable lever arm  310  that also is pinned at  300 . The adjustable lever arm  310  controls a brake assembly  320  that includes a spring  322  that biases a pawl  324  into engagement with the steering wheel  212 . Up and down movement of the handle  202  through angle “A” controls the application of the brake pawl  324 . The brake assembly  320  can be a “deadman” brake with the spring  322  being strong enough to apply the pawl  324  if the handle  202  is released by an operator. The spring  322  is mounted on an end of lever arm  310  and also to a bushing  326  carried on the frame  244 . The pawl  324  slides in the bushing  326 . 
         [0023]      FIG. 4  shows the brake assembly  320  in the braking position with the pawl  324  engaging the steering wheel  212 , and the spring  322  in its contracted position. It will be understood that as the steering wheel  212  is turned using handle  202 , the braking assembly  320  also rotates maintaining the pawl  324  above the steering wheel  212  at all times. Threaded member  330  can be used to adjust the position of the brake assembly  320  relative to the handle  202 . 
         [0024]      FIG. 5  is a partial cross-sectional view from above the spray applicator  200 . The shroud  230  is shown partially cutaway to expose the boom frame  400  that supports the lightweight shroud  230 , and a spray nozzle  402  contained in the shroud and receiving liquid from the pressurized tank  220  through hose  404  and electric pump  408 , which in turn receive fluid through hose  410 . An operator can monitor fluid pressure using gauge  420  which is mounted to the boom frame  400  through opening  422  in the shroud.  FIG. 5  also shows a secondary handle  430  provided to give ergonomic relief to the operator. Arrow “B” shows the directions that the handle  202  can turn about pivot  210 . Arrow “C” shows the normal direction of travel during application of liquid such that the spray applicator  200  trails the user.  FIG. 5  also shows a control  432  at the pump  408  that can control the rate of flow of liquid to the nozzles  402 . 
         [0025]      FIG. 6  shows a portion of the steering of the spray applicator  200 . The steering wheel  212  is held in a fork  602 . The fork  602  includes two (2) adjustable stops  604  that limit the amount of turn of wheel  212 , which allows an operator to adjust an amount of turn desired. The adjustable stops  604  can be bolts that impact on a fixed surface such as a frame  244 . 
         [0026]    In use, a user holds handle  202  by either grip  204  or  430  and walks in direction “C” with the spray applicator  200  trailing. Liquid fertilizer, herbicide or pesticide is pumped from tank  220  and is applied under the shroud  230  by nozzles  402 . The drive wheels  216  are powered at a constant speed to control the application of chemical. Adjustable stops  604  limit the rotation of handle  202  such that when an operator is turning  180  degrees for a next pass, the operator simply turns the handle to the stop and the system aligns for the next pass. In use, an operator can control the direction of travel of the spray applicator simply by pointing the long axis of the handle in the direction of travel desired. 
         [0027]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of the invention. It would be obvious to those skilled in the art that modifications may be made to the embodiments described above without departing from the scope of the present invention. Thus, the scope of the invention should be determined by the appended claims in the formal application and their legal equivalents, rather than by the examples given.