Background of the Invention
1. Field of the Invention
The present invention relates generally to the field of agricultural chemical applicators, and more particularly, is directed to a hand-held spot applicator including means to precisely adjust the flow rate of application.
2. Discussion of the Prior Art
Mechanisms to aid in the application of liquid agricultural chemicals to gardens, fields and other surface areas have long been a popular subject matter for prior workers in the art. Numerous types of mechanical applicators and sprayers have been developed to spread agricultural chemical products such as fertilizers, insecticides, pesticides, herbicides and the like and these prior art devices have been both manually and mechanically operated. More recently, the apparatus and equipment designed for vehicular transport has tended to become quite complicated in nature and expensive in manufacture and operation. Such types of spray apparatus have been designed for direct attachment to various types of vehicles including both ground vehicles and aircraft and such prior art equipment has generally proven to be effective in substantially uniformly applying the desired chemicals.
Agricultural chemical application equipment has also been particularly designed for manual use by an individual and it is in this particular area that the present invention finds special utility. In U.S. Pat. No. 3,648,935 by the inventor of the present application, a spray apparatus with a rotary movable head has been disclosed. In this apparatus, a movable rotary spray head is rotatively powered through associated apparatus including ground contacting wheels so that as the device is moved over the ground surface, the wheels generate rotary forces sufficient to rotate the rotary spray head. In other applications, the rotary spray head has been removed from the ground contacting wheels and has instead been equipped with a small electric motor for rotatively powering the spray head. By equipping the small motor with a suitable battery, a worker equipped with a suitable liquid storage tank can walk over the ground surface to be sprayed and the electric motor will provide the rotary energy necessary to turn the spray head for agricultural chemical application purposes.
In U.S. Pat. No. 2,162,057, a knapsack type of spraying apparatus has been disclosed wherein a worker can carry the liquid materials to be sprayed in a tank carried on his back. A hose interconnects the liquid contents stored within the tank with a rigid tube and nozzle through a control valve whereby the operator can apply the liquids directly upon the areas to be sprayed as he walks.
While the prior art applicators which are known to the applicant have generally been effective in applying the agricultural liquid chemicals directly upon selected target areas, so far as is known, the prior art devices require an integral pump or require that the tank be pressurized in order to generate sufficient forces for spray application purposes. Further the prior devices are rather randomly controlled and there is no known means to effectively apply a precisely controlled quantity of chemical product directly upon the target area. Under the circumstances, in view of the lack of precision capability of the presently available equipment, it has been found that some areas will receive more than the desired chemical treatment while others will receive less. Thus, the need remains to provide a readily controllable applicator that is capable of applying precise quantities of liquid chemicals in a continuous and reliable manner.
Summary of the Invention
The present invention relates generally to a volume controllable liquid chemical applicator, and more particularly, is directed to a self-contained, liquid applicator including easily adjustable means to precisely control the volume of the effluent upon each application.
The volume controllable applicator of the present invention is preferably adaptable for use as a spot gun for applying pesticides and the like and comprises generally a hollow housing, an elongate applicator tube that is reciprocal to the housing, an integral piston type pump secured to the housing, an operating handle pivotally secured to the housing and means to vary the pump stroke to precisely control the volume of effluent from the applicator upon each function of the pump.
A conveniently positioned, pivotal, operating handle reciprocates a piston within the pump cylinder to force the pesticide or other agricultural chemical through the applicator tube for direct application upon a target area. An easily adjustable collar secures to the applicator tube forwardly of the handle in a manner to limit the stroke of the piston to precisely control the effluent from the applicator upon each operation of the integral pump.
The integral pump of the volume controllable applicator comprises a reciprocal piston and a cylinder having a liquid inlet controlled by a first, automatic one-way valve. The piston is similarly provided with a second automatic, outlet one-way valve. The parts are so arranged and designed that when the piston is forwardly reciprocated in its suction stroke, the first cylinder inlet valve will automatically open and the second, piston outlet valve will close, to fill the cylinder with the agricultural liquid being sprayed. Upon rearward reciprocation of the piston in its power stroke, the second, outlet one-way valve will open and the first, cylinder inlet valve will close, thereby forcing the liquid contents of the cylinder through the applicator tube, and through the applicator nozzle for direct application upon the selected target area.
A volume control stop is positioned forwardly of the applicator housing and is threadedly engaged therein in a secure interconnection. The volume control stop receives a portion of the applicator tube therethrough in a reciprocating engagement. An adjustment collar is slidable along the applicator tube forwardly of the volume control stop and is provided to readily vary the stroke of the piston to consequently precisely control the amount of liquid chemical delivered through the spray nozzle upon each reciprocation of the pump piston. By adjusting the position of the collar upon the applicator tube relative to the forward end of the volume control stop, any desired flow volume can be achieved within the capability of the applicator. Preferably, an application range of between 1 cc per reciprocation to 8 cc per reciprocation has been found satisfactory for most applications. Of course, the application volume can be increased or decreased if so desired simply by constructing the pump cylinder to either an increased or decreased volumetric capacity whereby a greater or lessor discharge can be achieved upon each reciprocation of the piston.
It is therefore an object of the present invention to provide an improved volume controllable chemical liquid applicator of the type set forth.
It is another object of the present invention to provide a novel volume controllable applicator that incorporates in a unitary device a chemical liquid piston pump means, a spring biased handle means to manually reciprocate a piston within the pump means for liquid application purposes, an applicator tube means including a spray nozzle to direct the effluent from the pump means directly upon the target area and means to vary the stroke of the piston within the pump means to precisely control the quantity of flow upon each reciprocation of the piston.
It is another object of the present invention to provide a novel volume controllable applicator comprising a hollow housing, applicator tube means reciprocal within the housing to direct the liquid upon the target area, pump means connected to the applicator tube means to feed liquid chemical to the applicator tube means, operating handle means connected intermediate the housing and the applicator tube means to reciprocate a piston within the pump for delivery of the liquid to be applied through the applicator tube and means to vary the stroke of the piston to provide more or less liquid flow upon each reciprocation of the piston.
It is another object of the present invention to provide a novel volume controllable applicator comprising in combination piston pump means including a cylinder, a piston reciprocal within the cylinder, a first one-way valve to permit entrance of liquid chemical into the cylinder and a second one-way valve to direct the liquid chemical out of the cylinder, applicator tube means receiving the effluent from the cylinder through the second one-way valve, a housing receiving the applicator tube means therethrough, spring biased operating handle means interconnected between the housing and the applicator tube means to manually reciprocate the piston within the cylinder, and volume control means adjustably secured upon the applicator tube means to control the length of stroke of the piston upon each function of the operating handle means.
It is another object of the present invention to provide a novel volume controllable applicator that is simple in design, inexpensive in construction and trouble-free when in use.
Other objects and a fuller understanding of the invention will be had by referring to the following description and claims of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, wherein like reference characters refer to similar parts throughout the several views and in which:
Brief Description of the Drawing
FIG. 1 is a perspective view showing the volume controllable applicator of the present invention.
FIG. 2 is an enlarged, exploded, perspective view of the volume controllable applicator.
FIG. 3 is a side elevational view of the volume controllable applicator, partially broken away to expose interior construction details, and showing the operating handle in its applicating position.
FIG. 4 is a side elevational view similar to FIG. 3, showing the operating handle in its suction position.
FIG. 5 is an enlarged, partial, cross sectional view taken along line 5--5 on FIG. 3, looking in the direction of the arrows.
FIG. 6 is an enlarged, partial, cross sectional view taken along line 6--6 on FIG. 3, looking in the direction of the arrows.
Description of the Preferred Embodiment of the Invention
Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the invention selected for illustration in the drawings, and are not intended to define or limit the scope of the invention.
Referring now to the drawings, there is illustrated in FIG. 1 a volume controllable applicator in the nature of a spot gun 10 suitable to apply an agricultural liquid, for example a pesticide, directly upon a plant or other target area. The spot gun 10 comprises generally an elongate applicator tube 12, the applicator tube terminating at its forward end in a conventional nozzle 128 and at its rearward end in a piston type pump 136. A bent or tubular metal housing 14 extends forwardly from the pump 136 and forwardly supports an adjustable, volume control stop 26 for volume flow control purposes. An operating handle 16 pivotally connects a portion, for example, to the front end of the housing 14 and is spring biased to continuously urge the applicator tube 12 relative to the housing 14 toward an initial position.
As best seen in FIGS. 1 and 2, the housing 14 preferably is formed of sheet metal of suitable gage or strength for the purpose. The housing 14 may be stamped or otherwise worked to a generally U-shaped cross sectional configuration of configuration to loosely receive the rearward portion of the applicator tube 12 therewithin. The housing 14 terminates forwardly in a pair of spaced, depending tabs or ears 100, which tabs are provided with aligned openings 102 to receive a pivot pin or bolt 94 therethrough when the parts are assembled. The operating handle 16 may similarly preferably be fabricated of bent sheet steel or otherwise to form a handle portion having cooperating, spaced, upper extending tabs or ears 138. The ears 138 are similarly drilled or otherwise machined to provide aligned pivot openings 108 to receive the pivot bolt 94 therethrough. As shown, the operating handle ears 138 preferably are positioned interiorly of the depending ears 100 at the forward end of the housing 14 to minimize the required width of the operating handle 16.
As best seen in FIG. 2, a channel-shaped retainer 112 is provided at the housing front end assembly and comprises generally an arcuately shaped web and a pair of downwardly depending legs. The legs of the retainer 112 are similarly drilled or otherwise worked to provide aligned openings 114 to receive the pivot bolt 94 therethrough. As illustrated, the arcuate web of the retainer 112 is punched or otherwise worked to form a threaded surface to receive therein in threaded engagement the exterior threads 118 of the volume control stop 26. Accordingly, upon assembly of the parts, as shown in FIGS. 3 and 4, the volume control stop 26 can be threadedly engaged at the forward end of the housing 14 for pump stroke length adjustment purposes as hereinafter more fully set forth.
Still referring to FIGS. 1 and 2, and further considering FIGS. 3 and 4, the operating handle 16 is drilled or otherwise pierced to provide rearward boreholes 120. The rearward boreholes are suitably spaced from the pivot pin 94 to provide the required mechanical advantage when the applicator or spot gun 10 is in use. One end of an operating link 18 is drilled or otherwise worked to provide a transverse borehole 122 whereby a pivot pin 90 can be readily inserted through the aligned openings 120, 122 to provide a pivotal interconnection between the link 18 and the operating handle 16. The opposite end of the operating link 18 is similarly provided with an upper pivot borehole 124 whereby the opposite end of the link can be pivotally interconnected with the operating collar 20 by employing a conventional pivot bolt 92.
As shown, the operating collar 20 is designed and configured to clamp to and to encircle a rearward portion of the outer periphery of the applicator tube 12 and to easily slide within the hollow interior defined by the bent housing 14. Accordingly, by squeezing the operating handle 16 toward the housing 14, the operating link 18 and the pivotal connectors 90, 92 function to drive the operating collar 20 and the physically attached applicator tube 12 toward the piston pump cylinder 28. An operating spring 22 overfits a rearward portion of the applicator tube 12 and biases between the forward end of the piston pump 136 and the operating collar 20 to continuously bias the operating handle 16 toward its suction position 88 as illustrated in FIG. 4. Upon squeezing the operating handle 16 toward the housing 14, the link 18, the pivot pins 90, 92 and the operating collar 20 cooperatively function to drive the applicator tube 12 rearwardly by overcoming the bias of the spring 22 as the handle moves toward its applicating position 86 as illustrated in FIG. 3.
Referring now to FIGS. 2, 5 and 6, the piston pump 136 comprises a hollow cylinder 28 which terminates forwardly in an integral hollow extension 42. As shown, the extension 42 is provided with an axially aligned interior channel 140 to reciprocally receive the rearward portion of the applicator tube 12 therethrough upon piston operation as hereinafter more fully set forth. The cylinder extension 42 inserts into the rearward end of the housing 14 and is tightly secured therein by the clamping bolt 126 which is positioned and tightened through the openings 106 which are provided in the pair of opposed rearward housing tabs or ears 104. Upon tightening the bolt 126 in conventional manner, the rear end of housing 14 will be clamped around the extension 42 of the cylinder 28 and the housing and cylinder will be tightly secured together at the cylinder connector 42.
As best seen in FIGS. 5 and 6, the rearward end of the cylinder 28 is closed by a plug 32 of plastic or other sufficiently tough, sturdy material. Plug 32 has an exterior portion and an interior portion 142. The interior portion 142 snuggly fits within the interior 36 of the cylinder 28. The cylinder wall is pierced and tapped adjacent the rearward end at opening 144 to provide for a set screw 98 that extends into the interior portion 142 of the plug to firmly affix the plug 32 to the cylinder 28 in a leak-proof interconnection.
Still referring to FIGS. 5 and 6, and further considering FIG. 2, the cylinder end plug 32 is axially provided with a threaded opening 146 to threadably receive therein the supply inlet fitting 34 to introduce the liquid to be sprayed into the interior 36 of the cylinder 28. The inlet fitting 34 comprises a body 74 with a polygonal central portion and cooperating exteriorly threaded portions 148 and 76. The threaded portion 148 extends forwardly of the central polygonal portion of the body 74, that portion being preferably hexagonally formed to facilitate turning the supply inlet fitting 34 into the threaded opening 146 in a secure, known, leak-proof interconnection. The threaded opening 146 communicates with an axially aligned end plug flow channel 62 to form a conduit to direct the liquid to be sprayed (not shown) into the cylinder interior 36. The rearwardly extending inlet threaded portion 76 of the inlet fitting 34 is used for connecting to a liquid supply hose (not shown) in the usual manner. An inlet flow channel 78 is drilled or otherwise provided axially through the inlet fitting 34, which channel communicates with the end cap flow channel 62 via a one-way valve such as a ball check valve assembly in the inlet fitting 34.
The ball check valve assembly 64 comprises a seat 66, a ball 68 and a coil spring 70. The coil spring 70 resides in the spring recess 72 and functions to continuously bias the ball 68 against its seat 66 in known manner to normally close the first valve 64.
When the operating spring 22 biases the piston 30 toward its suction position 88 upon release of the operating handle 16 as illustrated in FIGS. 4 and 5, the bias of the coil spring 70 will be overcome by the suction forces created by forward movement of the piston 30 relative to the cylinder 28, thereby allowing the ball check valve 64 to open to admit the liquid to be sprayed (not shown) into the interior 36 of the cylinder 28.
As illustrated in FIGS. 5 and 6 and as partly shown in FIG. 2, the piston 30 is reciprocal within the interior 36 of the cylinder 28 and comprises generally a circular, peripheral recess 80 within which is positioned a suitably sized 0-ring gasket 82 to prevent liquid leakage and thus pressure loss between the outer periphery of the piston 30 and the inner wall 36 of the cylinder 28 as the piston is reciprocated between its suction position 88 (FIGS. 4 and 5) and its applicating position 86 (FIGS. 3 and 6).
The piston 30 is drilled or otherwise formed to provide a flow channel 46 therethrough, usually axially, and a communicating internally threaded recess 44 which recess is threadedly engaged with the externally threaded end 38 of the applicator tube 12. Accordingly, the piston will be reciprocated within the interior of the cylinder 28 upon function of the operating handle 16 to reciprocate the applicator tube 12 relative to the cylinder 28. A threaded recess 60 is rearwardly provided in the piston 30 in fluid communication with the flow channel 46 and the threaded recess 44 and is tapped or otherwise worked to receive an externally threaded valve plug 48 therewithin. Preferably, the valve plug 48 is provided with a rearward slot 50 to facilitate assembly in well known manner and also to provide fluid communication from the cylinder 28 to the axial bores 46 and 60 of the piston 30. The valve plug 48 is provided with a second one-way valve or ball check valve assembly 52 comprising a recess 60, a ball seat 54, a ball 56 and a ball-biasing coil spring 58. The coil spring 58 biases between the rearward end of the recess 60 and the ball 56 to normally tend to close the second one-way valve assembly 52.
When the operating handle 16 is squeezed toward the housing 14 from the suction position 88 as illustrated in FIGS. 4 and 5 toward the applicating position 86 as shown in FIGS. 3 and 6, the applicator tube 12 will be rearwardly urged against the bias of the operating spring 22 to simultaneously move the piston 30 in the direction toward the rearward end plug 32. This rearward movement will cause the liquid chemical within the interior 36 of the cylinder 28 to be compressed, thus forcing liquid into recess 60, moving the second valve assembly ball 56 off of the second valve ball seat 54 by overcoming the bias of the spring 58. The second one-way valve 52 will thus be opened to allow the fluid (not shown) within the cylinder 28 to be forced through the recess 60, the flow channel 46 and thence through the hollow interior 150 of the applicator tube 12 for subsequent delivery directly upon the target area. The hydraulic forces functioning to open the second one-way valve 52 operate in exactly the opposite direction to close the first one-way valve 64 by forcing the first ball 68 more tightly against its seat 66 to thereby prevent the exit of any of the agricultural chemical or other liquid backwardly through the supply inlet fitting 34.
The adjustment collar 24 positions over the outer periphery of the applicator tube 12 and is secured forwardly of the volume control stop 26 by a suitable adjustment or set screw 96. By adjusting the position of the adjustment collar 26 upon the applicator tube 12 relative to the forward end 152 of the volume control stop 26, the length of travel of the applicator tube 12, and hence the length of travel of the piston 30 relative to the cylinder 28 can be closely and precisely controlled. By carefully regulating the length of travel of the piston 30 within the cylinder 28, the quantity of liquid chemical delivered through the applicator tube 12 can be closely controlled inasmuch as the quantity of liquid chemical applied is directly proportional to the length of travel of the piston 30 within the cylinder 28.
As best seen in FIGS. 1 and 2, a threaded fitting 132 threadedly engages the threaded end 40 of the applicator tube 12 to receive thereon a conventional spray nozzle 128. The spray nozzle 128 can be secured to the external threads 154 of fitting 132 by employing a suitable threaded nut 134 in well known manner. Preferably, a valve 130 is associated with the nozzle 128 to prevent leakage of any liquid agricultural chemical that may remain within the applicator tube 12 when the spot gun 10 is not in active use.
Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention. Thus, the scope of the invention should not be limited by the foregoing specification, but rather, only by the scope of the claims appended hereto.