Abstract:
A handheld nozzle cleaning device includes a cylinder and piston disposed within the cylinder. The piston is movable between a latched position, in which air is compressed, and an unlatched position, in which air is drawn into the cylinder. The handheld nozzle cleaning device also includes a valve and a nozzle disposed at one end of the cylinder. Manual operation of the piston, defined by linear movement of the piston in a first direction, both releases the piston from the latched position and draws air into the cylinder. The compressed air flows out of the cylinder through the nozzle when the valve is opened. Also, manual operation of the piston in a second direction opposite the first direction both compresses air within the cylinder and secures the piston in the latched position.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 61/689,871 filed Jun. 14, 2012, the entire teachings and disclosure of which are incorporated herein by reference thereto. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to handheld cleaning tools. More particularly, the present invention relates to handheld cleaning tools for clearing debris from liquid application nozzles. 
     BACKGROUND OF THE INVENTION 
     Liquid application nozzles are commonly used in the application of water and chemicals in a wide variety of industries including but not limited to farming, agriculture, food processing, and industrial plants. Typically, a liquid application nozzle has a specially shaped internal orifice that causes the liquid forced through the nozzle to discharge in a pattern that distributes the liquid over a desired area. These are commonly referred to as spray nozzles, spray tips, sprayer nozzles, sprayer tips, or irrigation nozzles when referring to agricultural applications. During use, it is not uncommon for debris or foreign material to get lodged in the nozzle&#39;s orifice as the liquid is passing through the nozzle. Such debris can be introduced into the system&#39;s internal plumbing from corrosion, buildup, or poor quality liquid ingredients. Once debris partially or fully plugs a nozzle&#39;s orifice, the flow rate and distribution pattern are affected, and reduce the performance of the liquid application system. 
     Conventional practice involves removal of the nozzle from the supply piping and subsequently debris is removed from the nozzle by a one or more of the following methods. A brush is dragged across the nozzle to loosen the debris. Alternatively, the nozzle is tapped against a hard surface such that sudden impact with the hard surface causes the debris to break loose from the orifice. Alternatively, the nozzle is held up near one&#39;s mouth and an attempt is made to blow air through one&#39;s lips fast enough to dislodge the debris and clear the nozzle. The methods listed above are only moderately effective and can be difficult to accomplish with small nozzles, or when one is wearing rubber gloves for safety. 
     Given some of the above-mentioned problems associated with cleaning of liquid application nozzles, a more effective method of cleaning the nozzles involves using a blast of compressed gas passed backwards through the nozzle&#39;s orifice to dislodge the debris and eject it from the nozzle. For example, the compressed gas can be supplied from a hose attached to an air compressor, or produced from a small refillable or replaceable tank containing an aerosol or CO 2 -type propellant. 
     As is often the case with agricultural applications they are in farm fields where an air compressor and hose are not portable enough and therefore not a convenient option thus leaving the small cans of propellant as the best solution for this type of field application. When new the cans of propellant are convenient and effective but eventually the propellant becomes depleted and must be recharged or replaced. This becomes very inconvenient when in an agricultural field or under time constraints and trying to solve plugged nozzle problems quickly. 
     It would therefore be desirable to have a handheld portable apparatus which produces a blast of compressed gas for clearing debris from nozzles that does not require refilling or replacement of tanks or cans. It would also be desirable if the compressed gas was air and therefore would never require any maintenance to the gas supply. 
     Embodiments of the invention provide such an apparatus. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments of the present invention produce a blast of compressed air for clearing debris from the orifice of liquid application nozzles. Furthermore, embodiments of the present invention function by compressing a volume of ambient air to a pressure sufficiently greater than ambient pressure. The charge of compressed air is held in a chamber in until released through a valve activated by the user. The compressed air then discharges through a nozzle which focuses the air into the orifice which is to be cleaned. 
     Embodiments of the present invention provide a means of compressing the air by forcing a piston down a cylinder with a closed end. This compression is accomplished with a single stroke of the piston and is powered manually by the user therefore requiring no other power source such as batteries, liquefied compressed gas, or combustion of fuel. Once fully compressed a self activating latch holds the piston in the compressed position. 
     Embodiments of the present invention provide a means of releasing the compressed air through a valve which can be activated by a light pressing action from the user&#39;s finger. The valve has a nozzle attached which directs the released air toward the orifice being cleaned. The self activating latch functions to hold the piston in the compressed position until a release knob is pulled. The action of pulling the release knob not only releases the self activating latch but acts to pull the piston from the cylinder as the pulling action is continued. In this way the user&#39;s action of pulling on the piston to extend it serves a dual function of releasing the latch to allow free piston movement as well as extending the piston to ready if for producing another charge of compressed air. 
     Particular embodiments of the present invention provide a device that maximizes the compression stroke of the piston through the cylinder by containing the compressed air inside a hollow cavity in the piston rod when the compression stroke is complete. In this way the full length of the cylinder is used for compression since the head of the piston moves the entire length. 
     In one aspect, embodiments of the invention provide a handheld nozzle cleaning device includes a cylinder and piston disposed within the cylinder. The piston is movable between a latched position, in which air is compressed, and an unlatched position, in which air is drawn into the cylinder. The handheld nozzle cleaning device also includes a valve and a nozzle disposed at one end of the cylinder. Manual operation of the piston, defined by linear movement of the piston in a first direction, both releases the piston from the latched position and draws air into the cylinder. The compressed air flows out of the cylinder through the nozzle when the valve is opened. Also, manual operation of the piston in a second direction opposite the first direction both compresses air within the cylinder and secures the piston in the latched position. 
     In particular embodiments, a spring biases the valve in a closed position. Further, the cylinder, valve, spring, and nozzle may all be aligned axially. The valve is opened when a force sufficient to overcome the biasing force of the spring is applied to the nozzle in the axial direction. In an embodiment, the cylinder has an opening at the one end, the nozzle having a valve stem, configured to move within the opening, and a boss configured to cover the opening when the valve is in the closed position. 
     In a further embodiment, the nozzle has a passage that permits a flow of air from the valve stem out through an end of the nozzle when the valve is in the open position. The opening, valve stem, and boss may be centered on a longitudinal axis of the cylinder and piston. The cylinder has one or more openings therein, and wherein manual operation of the piston draws air from outside of the cylinder through the one or more openings into the cylinder. The piston may be hollow, such that manual operation of the piston compresses air within the piston. 
     In a particular embodiment, the piston includes a piston head that forms an air-tight seal within the cylinder. Furthermore, a vent hole in the cylinder allows for air into the cylinder when the piston head is not sealing against the vent hole. The air-tight seal may be maintained by an O-ring inserted into a groove in the piston head. 
     In certain embodiments, a latching mechanism is configured to keep the piston in place when compressed air is in the cylinder. In particular embodiments, the latching mechanism includes a hand knob, a bushing, and latching prongs attached to an end of the piston, wherein the hand knob is adapted to operate the piston for compressing air in the cylinder. The latching prongs may be configured to be flexed inward by movement of the hand knob, and also configured to extend through an opening in a cylindrical portion of the hand knob such that the latching prongs contact a portion of the bushing to keep the piston in place. In certain embodiments, the bushing is attached to an end of the cylinder opposite the end with nozzle. In a further embodiment, the piston is sized to fit completely inside of the cylinder when air is compressed in the piston. 
     Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a perspective view of a handheld nozzle cleaning apparatus, constructed in accordance with an embodiment of the invention; 
         FIG. 2  is a side view of the handheld nozzle cleaning apparatus of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the handheld nozzle cleaning apparatus of  FIG. 1 ; 
         FIG. 4  is a close up section detail view of the handheld nozzle cleaning apparatus of  FIG. 1  with piston latched; 
         FIG. 5  is a close up section detail view of the handheld nozzle cleaning apparatus of  FIG. 1  with piston unlatched; 
         FIG. 6  is an exploded view of the handheld nozzle cleaning apparatus of  FIG. 1 ; and 
         FIG. 7  is a perspective view of handheld nozzle cleaning apparatus of  FIG. 1  with piston extended. 
     
    
    
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A nozzle-cleaning apparatus  100  for cleaning nozzles, constructed in accordance with an embodiment of the invention, is shown in  FIGS. 1-7 . The apparatus  100  includes a cylinder  10  and a piston  20 . A valve and nozzle  30  is attached to the closed end  11  of cylinder  10 . A latch mechanism  400  is attached to one end of piston  20 . A hand knob  40  which also acts as a release for latch mechanism  400  is attached to the latch mechanism end of piston  20 . The entire nozzle cleaning apparatus  100  is sized to be held and operated in one hand of the user. Valve and nozzle  30  functions to release the charge of compressed air when depressed by one of the user&#39;s fingers. The cylinder  10  and piston  20  are centered on a longitudinal axis  301 . In a particular embodiment, the valve and nozzle  30  are also centered on longitudinal axis  301 . 
     Operation of the handheld nozzle cleaning apparatus  100  is as follows. The user grasps cylinder body  10  in one hand at the location of hand grip  14 . The user may then hold hand knob  40  with fingers of the other hand in a manner that allows a pulling force in the direction of  200  on hand knob  40 . Such pulling force  200  on hand knob  40  causes hand knob  40  to slide along portion  22  of piston  20  until the edges  43  of hand knob  40  come in contact latch prongs  25 . As pulling force  200  on hand knob  40  continues, edges  43  of hand knob  40  slide along latch prongs  25  and cause latch prongs  25  to be flexed inward until the tips  26  of latch prongs  25  are flexed, as shown in  FIG. 5 , such that they no longer protrude beyond the outer diameter of portion  41  of hand knob  40 . As this occurs, the head of screw  50  comes in contact with the seat  46  of hand knob  40  to limit further movement of hand knob  40  along portion  22  of piston  20 . 
     Further inward, flexing of latch prongs  25  is therefore stopped and pulling force  200  on hand knob  40  is now transferred to a pulling force on piston  20  through screw  50 . Since the tips  26  of latching prongs  25  are no longer protruding beyond the outer diameter of portion  41 , piston  20  is free to slide through the inner diameter  66  of bushing  60 . Pulling force  200  is continued on hand knob  40  until the piston head  27  is in contact with bushing  60 , which acts as a stop and notifies the user that the pulling operation is complete.  FIG. 7  shows handheld nozzle cleaning apparatus  100  in this fully extended state. At this point, piston head  27  has passed vent hole  16  in cylinder  10  allowing ambient air to enter cylinder  10  above piston head  27  until the air pressure inside cylinder  10  matches that of ambient. 
     Referring to  FIGS. 4 and 5 , the next phase of operation of the handheld nozzle cleaning apparatus  100  is to compress the air inside cylinder  10  above ambient and contain it for future use. This is accomplished by applying a pushing force  201  on hand knob  40 , which causes portion  41  to slide forward until it contacts a shoulder  28  on piston rod  21 . As hand knob  40  moves forward, edges  43  no longer make contact with latching prongs  25  and allow them to return to their normal non-deformed state such that their outer tips  26  move back into their original position taking a position with an effective outer diameter greater than the inside diameter  66  of bushing  60 . 
     As the pushing force  201  is continued on hand knob  40 , piston  20  is moved further into cylinder  10  such that piston head  27  passed by vent hole  16  in the side wall of cylinder  10  and results in complete containment of air inside cylinder  10  since piston head  27  is sealed by first O-ring  70 . Continued pushing force  201 , as described, presses piston head  27  through cylinder  10  and compresses all air trapped into cavity  29  inside piston  20  as piston head  27  nears the closed end  11  of cylinder  10 . In this way, the volume of space for the air trapped inside cylinder  10  as described has been greatly reduced and its pressure has been elevated above ambient. 
     As piston  20  finishes its movement fully into cylinder  10 , latch prongs  25  come into interference with the inner diameter  66  of bushing  60 , which causes them to flex inward and pass through bushing  60 . As latch prongs  25  clear the upper side  61  of bushing  60  they are no longer constrained in their flexed position and snap back to their natural position. This occurs at the same time that piston head  27  reaches its uppermost position. The user can no longer push piston  20  into cylinder  10 , and upon hearing the snap sound of the latch prongs  25  clearing bushing  60 , the user stops pushing on piston  20  and releases pressure  201  on hand knob  40 . The release of hand pressure  201  on hand knob  40  allows the air pressure held in cylinder  10  to push piston  20  back toward bushing  60 . Latch prongs  25  cannot pass back through the inner diameter  66  of bushing  60  and come to rest on the upper surface  61  of bushing  60 , as shown is  FIG. 4 , and therefore hold piston  20  inside cylinder  10  when all hand pressure  201  is removed from hand knob  40 . 
     Referring to  FIG. 3 , the handheld nozzle cleaning apparatus  100  now has air under pressure held within the inner cavity  29  of piston  20  ready to be released into the liquid application nozzle that requires debris to be cleared. Valve and nozzle  30  is used to release this compressed air. The user releases the compressed air by pressing in direction  300  on nozzle  34 . This force causes spring  33  to be compressed and moves valve stem  31  through a hole  13  in cylinder  10 . Second O-ring  32  is attached to valve stem  31 , and therefore moves away from the inner surface of the closed end  11  of cylinder  10  and allows the compressed air to flow through passage  35  in valve stem  31 , and into the passage  36  in nozzle  34 . The air then exits nozzle  34 , and is directed toward the liquid application nozzle being cleaned. 
     Now referring to  FIG. 3-6 , cylinder  10  is described in more detail. Cylinder  10  has an open end  12  and a closed end  11 . Closed end  11  has the hole  13 , which allows attachment and function of valve and nozzle  30 . Open end  12  is sized to accept a pressure-tight fit of piston head  27  when first O-ring  70  is installed into grove  23 . The length of cylinder  10  is selected to allow complete insertion of piston  20  including piston rod  21  and latch prongs  25 . The open end  12  of cylinder  10  is also sized to accept bushing  60 , with a means to attach bushing  60  to cylinder  10 , as shown in  FIG. 3-5 . Attachment of bushing  60  to cylinder  10  may be accomplished using glue, sonic welding, screws or pins. A particular embodiment  100  uses screws  80  to attach bushing  60  to cylinder  10 . Cylinder  10  also has a hand grip area  14 , which allows for a better grip by the user during operation. Cylinder  10  may be constructed of metal, plastic, or other suitable material. In a particular embodiment, cylinder  10  is constructed of molded plastic. It is noted that other methods of manufacture including machining will also suffice. It is also noted that hand grip  14  may be a separate piece, and not molded or fabricated as part of cylinder  10 . 
     Piston  20  is now described in more detail with reference to  FIG. 3-6 . Piston  20  has a piston head  27  at one end, sized to fit inside cylinder  10  with an air-tight seal when first O-ring  70  in installed in grove  23 . Piston head  27  is connected to piston rod  21  which contains cavity  29  that is open to the top of piston head  27 . Latch prongs  25  are attached to the opposite end of piston rod  21  of piston  20  and become a part of latch mechanism  400 . Latch mechanism  400  is comprised of latch prongs  25  which may be flexed inward during use. 
     The length of piston  20  is selected to fit completely inside cylinder  10  when bushing  60  is installed such that latch prongs may rest on the upper surface  61  of bushing  60 . Piston  20  may be constructed of metal, plastic, or other suitable material. In a particular embodiment, piston  20  is constructed of molded plastic. It is noted that other methods of manufacture including machining will also suffice. The thickness of latch prongs  25  is selected based on the material piston  20  is manufactured from, with a goal of allowing flexing of the latch prongs  25 , as described above, but still allowing them sufficient rigidity to withstand the forces required to hold piston  20  inside cylinder  10  when compressed air is being held inside cavity  29  and above piston head  27 . 
     Referring to  FIGS. 3-6 , hand knob  40  is described in more detail. Hand knob  40  has a large outer diameter portion sized to exceed the outer diameter of cylinder  10  such that it allows the user a place to grip when exerting pulling force  200 . Hand knob  40  also has a smaller diameter portion  41  that is sized to fit inside the inner diameter  66  of bushing  60 . Side openings  42  on hand knob  40  are sized to allow latch prongs  25  to pass through. During application of pulling force  200 , edges  43  of hand knob  40  come in contact with latch prongs  25  and cause them to flex inward, as shown in  FIG. 5 . When pushing force  201  is applied to hand knob  40 , edges  43  are released from contact with latch prongs  25  and therefore allow them to return to their natural un-flexed position, as shown in  FIG. 4 . 
     A central hole  44  and recess  45  allow screw  50  to pass through hand knob  40 . During use, hand knob  40  slides back and forth on screw  50  and shoulder  22  of piston  20  to allow operation of the latch mechanism. Recess  45  keeps the head of screw  50  from protruding beyond the surface of hand knob  40 , thus allowing for a projection free surface for the user to apply hand pressure  201  without discomfort. Hand knob  40  may be constructed of metal, plastic, or other suitable material. In a particular embodiment, hand knob  40  is constructed of molded plastic. It is noted that other methods of manufacture including machining will also suffice. 
     Referring to  FIGS. 4 and 5 , screw  50  is now described in greater detail. Screw  50  is sized to fit through hole  44  in hand knob  40  without interference. The head of screw  50  is sized to fit into recess  45  of hand knob  40 . The length of screw  50  is selected to allow engagement of screw  50  into hole  24  in piston rod  21  such that when properly engaged in hole  24 , hand knob  40  is allowed to slide from a compressed position as shown in  FIG. 4  to an extended position as shown in  FIG. 5 . Screw  50  may be of self threading type so no pre-forming of mating threads in hole  24  are required prior to assembly. It is further understood that screw  50  may be some other type of fastener such as bolt, press fit rod, or pin and serve the same function as screw  50 . Screw  50  may be constructed of metal, plastic or other suitable material. In the preferred embodiment screw  50  is constructed of metal and is self-threading. 
     In reference to  FIG. 3-6 , bushing  60  is now described in more detail. The outside diameter of bushing  60  is sized to fit inside cylinder  10  at the open end  12 . A means of attaching bushing  60  inside cylinder  10  is applied which may include gluing, ultrasonic welding, heat welding, or use of fasteners such as screws, pins or bolts. The inside diameter  66  of bushing  60  is sized to allow an interference-free slide of piston rod  21 , but such that latch prongs  25  will have to be flexed inwards to allow their passage through bushing  60 . The upper surface of bushing  60  contains a recess  62  with a diameter larger than the diameter of the inside diameter  66  but smaller than the outside diameter of bushing  60 . The diameter of recess  62  matches the effective outside diameter of the tips  26  of latch prongs  25 . 
     As latch prongs  25  come in contact with surface  61  of recess  62 , they are restrained from increasing their effective outside diameter which may result from the force required to retain piston  20  inside cylinder  10  when air is compressed and held in chamber  29  and above piston head  27 . Bushing  60  may contain a means of easing assembly to cylinder  10  by providing a stopping lip  63  to assure proper assembly of bushing  60  fully into cylinder  10  such that the recess  62  and surface  61  are located at the proper distance from the closed end  11  of cylinder  10  in reference to the total length of piston  20 . Bushing  60  may be constructed of metal, plastic or other suitable material. In certain embodiments, bushing  60  is constructed from injection molded plastic. It is noted that other methods of manufacture including machining will also suffice. 
     Now referring to  FIGS. 3 and 6 , valve and nozzle  30  is described in more detail. Valve and nozzle  30  consists of nozzle  34 , valve stem  31 , second O-ring  32 , and spring  33 . Valve stem  31  is sized to fit into hole  13  in the closed end of cylinder  10  with enough clearance to allow free movement but tight enough to limit air leakage when valve and nozzle  30  is activated by the user. A boss  37  of increased diameter is part of valve stem  31  to provide retention of second O-ring  32  when pressure is applied by spring  33  to hold valve and nozzle  30  closed. 
     Nozzle  34  has several features. First, it has an inner diameter sized to match the outer diameter of valve stem  31 . The clearance or interference of this fit is selected to allow permanent attachment of nozzle  34  to valve stem  31  by either gluing, welding, press fit, or threads or a combination thereof. The result is that, when assembled, nozzle  34  is fixed to valve stem  31  so that pressure from spring  33 , or finger pressure in the direction of  300 , will close or open valve and nozzle  30 , respectively. Valve stem  31  contains passage  35  which is exposed to the compressed air inside cylinder  10  when the valve and nozzle  30  is fully activated by finger pressure in the direction  300 . 
     Passage  35  is aligned with passage  36  in nozzle  34 , thus allowing compressed air to exit nozzle  34  when valve and nozzle  30  is activated by the user. When finger pressure is released or not present in the direction  300 , spring  33  applies a force that pushes nozzle  34  away from the closed end  11  of cylinder  10 , which by means of their permanent attachment causes the boss  37  of valve stem  31  to be pulled against second O-ring  32  thus sealing second O-ring  32  between the inside surface of the closed end  11  of cylinder  10  and the boss  37  of valve stem  31 . In this way, air compressed inside cylinder  10  may not exit valve and nozzle  30  when in the closed position, as shown in  FIG. 3 . Valve and nozzle  30  may be constructed of metal, plastic or other suitable materials. In a particular embodiment, nozzle  34  and valve stem  31  are constructed injection molded plastic. In certain embodiments, spring  33  is constructed of metal and is a compression type spring, while second O-ring  32  is constructed of rubber. It is noted that other methods of manufacture including machining will also suffice for nozzle  34  or valve stem  31 . 
     All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.