Patent Description:
Paint sprayers are well known and popular for use in painting of surfaces, such as on architectural structures, furniture and the like. Airless paint sprayers provide the highest quality finish amongst common sprayer system due to their ability to finely atomize liquid paint. In particular, airless paint sprayers pressurize liquid paint to upwards of <NUM>,<NUM> psi [pounds per square inch] (~<NUM> MPa) and discharge the paint through small, shaped orifices. Typical airless spray systems, however, require a large stationary power unit, such as an electric motor, a gasoline motor or an air compressor, and a large stationary pumping unit. The power unit is connected to a stationary paint source, such as a <NUM> gallon bucket, and a spray gun. Thus, such units are well suited for painting large areas that require high quality finishes.

It is, however, often desirable to paint smaller areas for which it is not desirable or feasible to set up an airless spray system. For example, it is desirable to provide touch-up and trim areas having finishes that match the originally painted area. Various types of handheld spray systems and units have been developed to address such situations. For example, buzz guns or cup guns, as they are commonly referred to, comprise small handheld devices electrically powered by connection to a power outlet. Such units do not provide professional grade finishes because, among other things, the low pressures generated and inferior spray nozzles that must be used with the low pressures. There is, therefore, a need for a portable, handheld spray device that produces professional grade finishes.

<CIT> discloses a handheld spray gun having a fixed nozzle and a handle attached to a housing of the gun.

<CIT>, <CIT>, <CIT> and <CIT> are also relevant.

The present invention is directed to a handheld airless sprayer as defined in claim <NUM>.

Embodiments of the present invention will now be described by way of further example only and with reference to the accompanying drawings, in which:.

The examples on <FIG> are not defined by the appended claims.

<FIG> shows a block diagram of portable airless fluid dispensing device <NUM> of the present invention. In the embodiment shown, device <NUM> comprises a portable airless spray gun comprising housing <NUM>, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM>. In various embodiments of the invention, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> are packaged together in a portable spraying system. For example, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> can each be mounted directly to housing <NUM> to comprise an integrated handheld device, as described with respect to <FIG>. In other embodiments, fluid container <NUM> can be separated from housing <NUM> and connected to spray tip assembly <NUM>, pumping mechanism <NUM> and drive element <NUM> via a hose, as shown in <FIG>. In still other embodiments, spray tip assembly <NUM> can be separated from housing <NUM> and connected to fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> via a hose, as shown in <FIG>.

In all embodiments, sprayer <NUM> comprises an airless dispensing system in which pumping mechanism <NUM> draws fluid from container <NUM> and, with power from drive element <NUM>, pressurizes the fluid for atomization through spray tip assembly <NUM>. Pumping mechanism <NUM> comprises, in different embodiments, a gear pump, a piston pump, a plunger pump, a vane pump, a rolling diaphragm pump, a ball pump, a rotary lobe pump, a diaphragm pump or a servo motor having a rack and pinion drive. Drive element <NUM> comprises, in different embodiments, an electric motor, an air-driven motor, a linear actuator or a gas engine which can be used to drive cams, a wobble plate or rocker arms. In one embodiment, pumping mechanism <NUM> generates orifice spray pressure, or running pressure, of about <NUM> pounds per square inch [psi] (~<NUM> MPa) up to about <NUM> psi (~<NUM> MPa) or higher, as driven by drive element <NUM>. However, pumping mechanism <NUM> may be able to generate pressures up to about <NUM>,<NUM> psi (~<NUM> MPa) to approximately <NUM>,<NUM> psi (~<NUM> MPa). Combined with spray tip assembly <NUM>, which includes a spray orifice having an area as small as about <NUM> square inches (~<NUM><NUM>) to about <NUM> square inches (~<NUM><NUM>), sprayer <NUM> achieves atomization of fluid architectural coatings, such as paint, stains, varnishes and lacquers, to about <NUM> microns or smaller, or about <NUM> microns or smaller on a Dv(<NUM>) scale.

<FIG> shows a side perspective view of spray gun <NUM> having housing <NUM>, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> (disposed within housing <NUM>) and drive element <NUM> (disposed within housing <NUM>). Spray gun <NUM> also includes pressure relief valve <NUM>, trigger <NUM> and battery <NUM>. Spray tip assembly <NUM> includes guard <NUM>, spray tip <NUM> and connector <NUM>. Drive element <NUM> and pumping mechanism <NUM> are disposed within housing <NUM>. Housing <NUM> includes integrated handle <NUM>, container lid <NUM> and battery port <NUM>.

Fluid container <NUM> is provided with a fluid that is desired to be sprayed from spray gun <NUM>. For example, fluid container <NUM> is filled with a paint or varnish that is fed to spray tip assembly <NUM> through coupling with lid <NUM>. Battery <NUM> is plugged into battery port <NUM> to provide power to drive element <NUM> within housing <NUM>. Trigger <NUM> is connected to battery <NUM> and drive element <NUM> such that upon actuation of trigger <NUM> a power input is provided to pumping mechanism <NUM>. Pumping mechanism <NUM> draws fluid from container <NUM> and provides pressurized fluid to spray tip assembly <NUM>. Connector <NUM> couples spray tip assembly <NUM> to pump <NUM>. Tip guard <NUM> is connected to connector <NUM> to prevents objects from contacting high velocity output of fluid from spray tip <NUM>. Spray tip <NUM> is inserted through bores within tip guard <NUM> and connector <NUM> and includes a spray orifice that receives pressurized fluid from pumping mechanism <NUM>. Spray tip assembly <NUM> provides a highly atomized flow of fluid to produce a high quality finish. Pressure relief valve <NUM> is connected to pumping mechanism <NUM> to open the mechanism to atmospheric pressure.

<FIG> shows an exploded view of spray gun <NUM> having housing <NUM>, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM>. Spray gun <NUM> also includes pressure relief valve <NUM>, trigger <NUM>, battery <NUM>, clip <NUM>, switch <NUM> and circuit board <NUM>. Spray tip assembly <NUM> includes guard <NUM>, spray tip <NUM>, connector <NUM> and barrel <NUM>. Pumping mechanism <NUM> includes suction tube <NUM>, return line <NUM> and valve <NUM>. Drive element <NUM> includes motor <NUM>, gearing assembly <NUM> and connecting assembly <NUM>. Housing <NUM> includes integrated handle <NUM>, container lid <NUM> and battery port <NUM>.

Pumping mechanism <NUM>, drive element <NUM>, gearing <NUM>, connection assembly <NUM> and valve <NUM> are mounted within housing <NUM> and supported by various brackets. For example, gearing <NUM> and connection assembly <NUM> include bracket <NUM> which connects to bracket <NUM> of pumping mechanism <NUM> using fasteners <NUM>. Valve <NUM> is threaded into bracket <NUM>, and connector <NUM> of spray tip <NUM> is threaded onto valve <NUM>. Spray tip <NUM>, valve <NUM>, pumping mechanism <NUM> and drive element <NUM> are supported within housing <NUM> by ribs <NUM>. In other embodiments of gun <NUM>, housing <NUM> includes ribs or other features for directly supporting gearing <NUM> and connecting assembly <NUM> without the use of bracket <NUM>. Switch <NUM> is positioned above handle <NUM> and circuit board <NUM> is positioned below handle <NUM> such that trigger <NUM> is ergonomically positioned on housing <NUM>. Switch <NUM> includes terminals for connecting with drive element <NUM>, and battery <NUM> is supported by port <NUM> of housing <NUM> in such a manner so as to connect with circuit board <NUM>. Circuit board <NUM> can be programmed to change voltage supplied to drive element <NUM> to vary flow from pumping mechanism <NUM>, and to limit current and voltage. Additionally, circuit board <NUM> can be programmed to use pulse width modulation (PWM) to slow output of drive element <NUM> when high current is being drawn. In another embodiment, a temperature sensor is incorporated into board <NUM> to monitor temperatures in the electrical system of spray gun <NUM>, such as temperature of battery <NUM>. Battery <NUM> may comprise a Lithium battery, a Nickel battery, a Lithium-ion battery or any other suitable rechargeable battery. In one embodiment, battery <NUM> comprises a <NUM> VDC battery, although other lower or higher voltage batteries can also be used. Fluid container <NUM> is threaded into lid <NUM> of housing <NUM>. Suction tube <NUM> and return line <NUM> extend from pumping mechanism <NUM> into fluid container <NUM>. Clip <NUM> allows gun <NUM> to be conveniently stowed such as on a belt of an operator or a storage rack.

To operate gun <NUM>, fluid container <NUM> is filled with a liquid to be sprayed from spray tip <NUM>. Trigger <NUM> is actuated by an operator to activate drive element <NUM>. Drive element <NUM> draws power from battery <NUM> and causes rotation of a shaft connected to gearing <NUM>. Gearing <NUM> causes connection mechanism <NUM> to provide an actuation motion to pumping mechanism <NUM>. Pumping mechanism <NUM> draws liquid from container <NUM> using suction tube <NUM>. Excess fluid not able to be processed by pumping mechanism <NUM> is returned to container <NUM> through priming valve <NUM> and return line <NUM>. Pressurized liquid from pumping mechanism <NUM> is provided to valve <NUM>. Once a threshold pressure level is achieved, valve <NUM> opens to allow pressurized liquid into barrel <NUM> of spray tip <NUM>. Barrel <NUM> includes a spray orifice that atomizes the pressurized liquid as the liquid leaves spray tip <NUM> and gun <NUM>. Barrel <NUM> may comprise either a removable spray tip that can be removed from tip guard <NUM>, or a reversible spray tip that rotates within tip guard <NUM>.

<FIG> shows an exploded view of pumping mechanism <NUM> and drive element <NUM> of <FIG>. Pumping mechanism <NUM> includes bracket <NUM>, fasteners <NUM>, inlet valve assembly <NUM>, outlet valve assembly <NUM>, first piston <NUM> and second piston <NUM>. Drive element <NUM> includes drive shaft <NUM>, first gear <NUM>, first bushing <NUM>, second gear <NUM>, shaft <NUM>, second bushing <NUM>, third bushing <NUM>, third gear <NUM>, fourth bushing <NUM> and fourth gear <NUM>. Connecting mechanism <NUM> includes connecting rod <NUM>, bearing <NUM>, rod <NUM> and sleeve <NUM>. First piston <NUM> includes first piston sleeve <NUM> and first piston seal <NUM>. Second piston <NUM> includes second piston sleeve <NUM> and second piston seal <NUM>. Inlet valve <NUM> includes first valve cartridge <NUM>, seal <NUM>, seal <NUM>, first valve stem <NUM> and first spring <NUM>. Outlet valve <NUM> includes second valve cartridge <NUM>, seat <NUM>, second valve stem <NUM> and second spring <NUM>.

Drive shaft <NUM> is inserted into bushing <NUM> such that gear <NUM> rotates when drive element <NUM> is activated. Bushing <NUM> and gear <NUM> may be integrally formed as one component. Bushings <NUM> and <NUM> are inserted into a receiving bore within bracket <NUM>, and shaft <NUM> is inserted into bushings <NUM> and <NUM>. Gear <NUM> is connected to a first end of shaft <NUM> to mesh with gear <NUM>, and gear <NUM> is connected with a second end of shaft <NUM> to mesh with gear <NUM>. Gear <NUM>, shaft <NUM>, gear <NUM> and bushing <NUM> may be formed as one component. Sleeve <NUM> is inserted into a receiving bore within bracket <NUM> and rod <NUM> is inserted into sleeve <NUM> to support connecting mechanism <NUM>. Bearing <NUM> connects rod <NUM> to connecting rod <NUM>. Connecting rod <NUM> couples with first piston <NUM>. First piston <NUM> and second piston <NUM> are inserted into piston sleeves <NUM> and <NUM>, respectively, which are mounted within pumping chambers within bracket <NUM>. Valve seal <NUM> and sleeve <NUM> seal the pumping chambers. Fasteners <NUM> are inserted through bores in bracket <NUM> and bushings <NUM> and threaded into bracket <NUM>. First valve cartridge <NUM> is inserted into a receiving bore in bracket <NUM>. First spring <NUM> biases valve stem <NUM> against cartridge <NUM>. Similarly, second valve cartridge <NUM> is inserted into a receiving bore in bracket <NUM> such that spring <NUM> biases valve stem <NUM> against bracket <NUM>. Valve cartridges <NUM> and <NUM> are removable from bracket <NUM> such that valve stems <NUM> and <NUM> can be easily replaced. Seals <NUM> and <NUM> prevent fluid from leaking out of valve <NUM>, and seat <NUM> prevents fluid from leaking out of valve <NUM>. Valve <NUM> is inserted into a receiving bore in bracket <NUM> to intersect fluid flow from pistons <NUM> and <NUM>.

<FIG> shows a perspective view of connecting mechanism <NUM> of <FIG>. Connecting mechanism <NUM> includes rod <NUM>, upon which land <NUM>, bearing <NUM>, connecting rod <NUM> and gear <NUM> are attached. Connecting mechanism provides a connection between drive element <NUM> and pumping mechanism <NUM>. Piston <NUM> is connected to connecting rod <NUM> by a ball and socket, or plug and protrusion, arrangement. Connecting mechanism <NUM> converts rotational shaft power from drive element <NUM> to reciprocating motion for piston <NUM>. As is better illustrated in <FIG>, rotation of rod <NUM> via gear <NUM> produces wobble of connecting rod <NUM> through land <NUM>, which has a surface with an offset axis of rotation. In various embodiments of the invention, rod <NUM> and land <NUM> are integrally formed as one component. However, in other embodiments, connecting mechanism <NUM> may comprise a scotch yoke or another system for converting rotational motion to linear motion.

<FIG> shows a cross-sectional view of connecting mechanism <NUM> of <FIG> with connecting rod <NUM> in an advanced position. <FIG> shows a cross-sectional view of connecting mechanism <NUM> of <FIG> with connecting rod <NUM> in a retracted position. Connecting mechanism <NUM> includes gear <NUM>, connecting rod <NUM>, bearing <NUM>, rod <NUM>, sleeve <NUM>, land <NUM> and bushing <NUM>. In such a configuration, connecting mechanism <NUM> comprises a wobble assembly. <FIG>, which are discussed concurrently, illustrate the reciprocating motion generated by land <NUM> when subjected to rotational movement. Rod <NUM> is supported at a first end by sleeve <NUM>, which is supported in bracket <NUM> of pumping mechanism <NUM>. Rod <NUM> is supported at a second end, through land <NUM>, by bushing <NUM>, which is supported in bracket <NUM>. Land <NUM> is disposed about rod <NUM> and includes a bushing seat for bushing <NUM>, a gear seat for gear <NUM>, and wobble seat <NUM> for connecting rod <NUM>. Connecting rod <NUM> includes ball <NUM>, which is disposed in a socket within piston <NUM>.

Gear <NUM> rotates land <NUM> and rod <NUM>, which rotates within sleeve <NUM> and bushing <NUM>. Wobble seat <NUM> comprises a cylindrical-like structure having a surface revolved about an axis that is offset from the axis about which land <NUM> and rod <NUM> rotate. As land <NUM> revolves, the axis of wobble seat <NUM> orbits the axis of rod <NUM>, making a cone-like sweep. Bearing <NUM> is disposed in a plane transverse to the axis of wobble seat <NUM>. As such, bearing <NUM> undulates, or wobbles, with respect to a plane transverse to rod <NUM>. Connecting rod <NUM> is connected to the outer diameter end of bearing <NUM>, but is prevented from rotating about rod <NUM> by ball <NUM>. Ball <NUM> is connected to piston <NUM>, which is disposed within a piston seat in bracket <NUM> such that rotation is prevented. Ball <NUM> is, however, permitted to move in the axial direction as bearing <NUM> wobbles. Thus, rotational motion of wobble seat <NUM> produces linear motion of ball <NUM> to drive pumping mechanism <NUM>.

<FIG> shows a cross-sectional view of pumping mechanism <NUM> assembled with drive element <NUM>. Drive element <NUM> comprises a mechanism or motor for producing rotation of drive shaft <NUM>. In the embodiment shown, drive element <NUM> comprises a DC (direct current) motor that receives electrical input from battery <NUM>, or another electrical power source. In other embodiments, drive element comprises an AC (alternating current) motor that receives electrical input by plugging into a power outlet. In various other embodiments, drive element may comprise a pneumatic motor that receives compressed air as an input, a linear actuator, a gas engine or a brushless DC motor. A compressed air motor or a brushless DC motor provide intrinsically safe drive elements that eliminate or significantly reduce electrical and thermal energy from the drive element. This allows for use of spray gun <NUM> with combustible or flammable liquids or in environments where combustible, flammable or other hazardous materials are present. First gear <NUM> is fit over drive shaft <NUM> and is held in place by bushing <NUM>. Bushing <NUM> is secured to shaft <NUM> using a setscrew or another suitable means.

First gear <NUM> meshes with second gear <NUM>, which is connected to shaft <NUM>. Shaft <NUM> is supported in bracket <NUM> by bushings <NUM> and <NUM>. Gear <NUM> is disposed on a reduced diameter portion of shaft <NUM> and secured in place using bushing <NUM>. Bushing <NUM> is secured to shaft <NUM> using a setscrew or another suitable means. Gear <NUM> meshes with gear <NUM> to rotate rod <NUM>. Rod <NUM> is supported by sleeve <NUM> and bushing <NUM> in brackets <NUM> and <NUM>, respectively. Gears <NUM>, <NUM>, <NUM> and <NUM> provide a gear reduction means that slows the input to rod <NUM> from the input provided by drive element <NUM>. Depending on the type of pumping mechanism used and the type of drive element used, various sizes of gears and gear reductions can be provided as is needed to produce the desired operation of pumping mechanism <NUM>. For example, pumping mechanism <NUM> needs to be operated at speeds sufficient for generating desired fluid pressures. Specifically, in order to provide highly desirable, fine finishes with sprayer <NUM>, pressures of about <NUM>,<NUM> psi (pounds per square inch) [~<NUM> MPa] to <NUM>,<NUM> psi [~<NUM> MPa] are advantageous. In one embodiment of pumping mechanism <NUM>, a gear reduction of approximately <NUM> to <NUM> is used with a typical 18V DC motor. In another embodiment of pumping mechanism <NUM>, a gear reduction of approximately <NUM> to <NUM> is used with a typical 120V DC motor, using a DC to AC bridge.

As is described with respect to <FIG>, rotation of rod <NUM> produces linear motion of ball <NUM> of connecting rod <NUM>. Ball <NUM> is mechanically connected to socket <NUM> of piston <NUM>. Thus, connecting rod <NUM> directly actuates piston <NUM> in both advanced and retracted positions. Piston <NUM> advances and retracts within piston sleeve <NUM> in bracket <NUM>. As piston <NUM> retreats from the advanced position, fluid is drawn into valve <NUM>. Valve <NUM> includes stem <NUM> to which suction tube <NUM> connects. Suction tube <NUM> is submerged within a liquid inside fluid container <NUM> (<FIG>). The liquid is drawn into pumping chamber <NUM> around valve stem <NUM> and through inlet <NUM>. Valve stem <NUM> is biased against valve cartridge <NUM> by spring <NUM>. Seal <NUM> prevents fluid from passing between cartridge <NUM> and stem <NUM> when stem <NUM> is closed. Seal <NUM> prevents fluid from passing between cartridge <NUM> and bracket <NUM>. Valve stem <NUM> is drawn away from cartridge <NUM> by suction produced by piston <NUM>. As piston <NUM> advances, fluid within pumping chamber <NUM> is pushed through outlet <NUM> toward valve <NUM>.

Fluid pressurized in chamber <NUM> is pushed into pressure chamber <NUM> around valve stem <NUM> of valve <NUM>. Valve stem <NUM> is biased against bracket <NUM> by spring <NUM>. Seat <NUM> prevents fluid from passing between stem <NUM> and bracket <NUM> when stem <NUM> is closed. Valve stem <NUM> is forced away from bracket <NUM> as piston <NUM> moves toward the advanced position, as spring <NUM> and the pressure generated by piston <NUM> closes valve <NUM>. Pressurized fluid from pumping chamber <NUM> fills pressure chamber <NUM>, comprising the space between cartridge <NUM> and bracket <NUM>, and pumping chamber <NUM>. The pressurized fluid also forces piston <NUM> to the retracted position. Cartridge <NUM> reduces the volume of pressure chamber <NUM> such that less fluid is stored within pumping mechanism <NUM> and the velocity of fluid being passed through mechanism <NUM> is increased, which assists in clean up. The volume of pumping chamber <NUM> and the displacement of piston <NUM> is larger than the displacement of piston <NUM> and the volume of pumping chamber <NUM>. In one embodiment, the displacement of piston <NUM> is twice as large as the displacement of piston <NUM>. In another embodiment, piston <NUM> has a <NUM> inch (~<NUM>) diameter with a <NUM> inch (~<NUM>) stroke, and piston <NUM> has a <NUM> inch (~<NUM>) diameter with a <NUM> inch (~ <NUM>) stroke. As such, a single stroke of piston <NUM> provides enough fluid to fill pumping chamber <NUM> and maintain pressure chamber filled with pressurized fluid. Additionally, piston <NUM> has a large enough volume to push pressurized fluid through outlet <NUM> of bracket <NUM>. Providing suction from only a single, larger piston provides improved suction capabilities over providing suction by two smaller pistons.

As piston <NUM> retreats to draw additional fluid into pumping chamber <NUM>, piston <NUM> is pushed forward by connecting rod <NUM>. Piston <NUM> is disposed within piston sleeve <NUM> in bracket <NUM>, and piston seal <NUM> prevents pressurized fluid from escaping pumping chamber <NUM>. Piston <NUM> advances to evacuate fluid pushed into pumping chamber <NUM> by piston <NUM>. The fluid is pushed back into pressure chamber <NUM> and through outlet <NUM> of bracket <NUM>. Piston <NUM> and piston <NUM> operate out of phase with each other. For the specific embodiment shown, piston <NUM> is one-hundred eighty degrees out of phase with piston <NUM> such that when piston <NUM> is at its most advanced position, piston <NUM> is at its most retracted position. Operating out of phase, pistons <NUM> and <NUM> operate in synch to provide a continuous flow of pressurized liquid to pressure chamber <NUM> while also reducing vibration in sprayer <NUM>. In one embodiment, pumping mechanism operates at approximately <NUM>,<NUM> pulses per minute with each piston operating at approximately <NUM>,<NUM> strokes per minute. Pressure chamber <NUM> acts as an accumulator to provide a constant flow of pressurized fluid to outlet <NUM> such that a continuous flow of liquid can be provided to valve <NUM> and spray tip assembly <NUM> (<FIG>). In other embodiments, additional mechanical means can be connected to pressure chamber <NUM> to provide an assisted accumulator device. For example, pressure chamber <NUM> can be connected to a bladder, diaphragm, hose or bellows to provide external pressure to fluid passing through chamber <NUM> to outlet <NUM>. In particular, a hose can be used to connect pumping mechanism <NUM> to spray tip assembly <NUM> to provide an accumulator function, as shown in <FIG>, for example.

Pumping mechanism <NUM> may comprise a double-displacement single piston pump in which a single piston pressures two cylinders one-hundred eighty degrees out of phase. In other embodiments, three or more pumping chambers may be pressurized out of phase to provide an even more smooth spray distribution. For example, a triplex plunger or piston pump may be used. In yet other embodiments, a gerotor (generated rotor), gear pump or rotary vane pump may be used.

<FIG> shows a side cross-sectional view of valve <NUM> and spray tip assembly <NUM>. <FIG>, which is discussed concurrently with <FIG>, shows a bottom cross-sectional view of valve <NUM> and spray tip assembly <NUM>. Valve <NUM> includes cylinder <NUM>, cap <NUM>, ball tip <NUM>, seal <NUM>, needle <NUM>, spring <NUM>, seal <NUM>, spring dampers <NUM> and <NUM>, seal <NUM>, seal <NUM>, stopper <NUM>, fluid passage <NUM> and filter <NUM>. Spray tip assembly <NUM> includes guard <NUM>, connector <NUM>, spray tip <NUM>, which includes barrel <NUM>, seat <NUM> and spray orifice <NUM>.

Cylinder <NUM> of valve <NUM> is threaded into a socket within bracket <NUM> of pumping mechanism <NUM>. Seal <NUM> prevents fluid from leaking between bracket <NUM> and cylinder <NUM>. Spring damper <NUM>, spring <NUM> and spring damper <NUM> are positioned around needle <NUM>, and filter <NUM> is positioned around needle <NUM> and spring <NUM>. Stopper <NUM> is inserted into axial bore <NUM> within cylinder <NUM>. Needle <NUM> and filter <NUM> are inserted into cylinder <NUM> and needle <NUM> extends into axial bore <NUM> within cylinder <NUM>. Seal <NUM> prevents fluid from leaking into the axial bore within cylinder <NUM>. Filter <NUM> connects cap <NUM> with cylinder <NUM> to extend fluid passage <NUM> in an annular flow path toward cap <NUM>. Cap <NUM> is inserted into fluid passage <NUM> of cylinder <NUM>. Seal <NUM> prevents fluid from leaking between cylinder <NUM> and cap <NUM>. Seal <NUM> is inserted into cap <NUM> to surround integrated ball tip <NUM> of needle <NUM>. Connector <NUM> is threaded onto cylinder <NUM> to maintain seal <NUM> engaged with cap <NUM> and needle <NUM> disposed within cylinder <NUM>.

Spray orifice <NUM> is inserted into bore <NUM> within barrel <NUM> of spray tip <NUM> and abuts shoulder <NUM>. Seat <NUM> is inserted into bore <NUM> and maintains orifice <NUM> against shoulder <NUM>. Spray tip <NUM> is inserted into transverse bore <NUM> in cap <NUM> such that seat <NUM> aligns with needle <NUM>. Ball tip <NUM> is biased against seat <NUM> by spring <NUM>. Seat <NUM> includes a contoured surface for engaging ball tip <NUM> such that flow of pressurized fluid is prevented from entering spray tip <NUM>. Guard <NUM> is positioned around cap <NUM>.

Upon activation of pumping mechanism <NUM>, such as by operation of trigger <NUM>, pressurized fluid is provided to outlet <NUM>. Fluid from pumping mechanism <NUM> is pushed into valve <NUM> through outlet <NUM>. The fluid travels through fluid passage <NUM>, around filter <NUM>, to engage cap <NUM>. At cap <NUM>, the pressurized fluid is able to pass between cap <NUM> and needle <NUM> at passage <NUM> (as shown in <FIG>) so as to be positioned between seal <NUM> and land <NUM> of needle <NUM>. The pressure of the fluid against land <NUM>, and other forward facing surfaces of needle <NUM>, forces needle <NUM> to retract within cylinder <NUM>. Spring <NUM> compresses between dampers <NUM> and <NUM>, which inhibit spring <NUM> from vibrating during pulsation of the pressurized fluid from pumping mechanism <NUM>. Stopper <NUM> inhibits needle <NUM> from moving too far and reduces the impact of needle <NUM> against cylinder <NUM>. In one embodiment, spring <NUM> fully compresses at approximately <NUM>,<NUM> psi (~<NUM> MPa) and is closed at approximately <NUM> psi (~<NUM> MPa). With needle <NUM> retracted, pressurized fluid is able to pass into seal <NUM> and into bore <NUM> of seat <NUM>. From bore <NUM>, the pressurized fluid is atomized by orifice <NUM>. In one embodiment, orifice <NUM> atomizes un-thinned (e.g. no water is added to reduce viscosity) architectural coatings to about approximately <NUM> microns using an orifice diameter of approximately <NUM> square inches (-<NUM>,<NUM><NUM>). In another embodiment, orifice <NUM> atomizes the pressurized architectural coating to about approximately <NUM> microns on a Dv(<NUM>) scale.

In other embodiments of the invention, valve <NUM> may comprise an assembly in which seat <NUM> is integrated into cylinder <NUM>, as is shown and discussed later in greater detail with reference to <FIG>. For example, a pressure actuated shutoff valve may be used, such as a Cleanshot™ shutoff valve available from Graco Minnesota Inc. , Minneapolis, MN. Such valves are described in <CIT>et al. , which is assigned to Graco Minnesota Inc. For example, with valve seat <NUM> disposed in cylinder <NUM>, needle <NUM> does not extend all the way up to barrel <NUM>. As such, the space between orifice <NUM> and ball tip <NUM> is extended such that bore <NUM> is effectively lengthened. This leaves a significant volume of liquid within bore <NUM> after activation of pumping mechanism <NUM> and closing of valve <NUM>. This liquid remains un-atomized upon a subsequent activation of pumping mechanism <NUM>, potentially causing undesirable spitting or splattering of fluid. Such a spray tip comprises a conventional design and an exemplary embodiment is described in <CIT>et al. , which is assigned to Graco Minnesota Inc.

However, the embodiment of <FIG> and <FIG> achieves advantages over such designs. Seat <NUM> and spray orifice <NUM> are integrated into barrel <NUM> such that when spray tip <NUM> is removed from spray tip assembly <NUM>, seat <NUM> and orifice <NUM> are also removed. This reduces the number of parts as compared to previous designs. For example, additional seals and fastening element are not needed. Also, integration of orifice <NUM> into barrel <NUM> reduces the volume of un-atomized fluid sprayed from orifice <NUM>. Specifically, the space between orifice <NUM> and ball tip <NUM> is shortened by moving seat <NUM> into barrel <NUM> and lengthening needle <NUM> to reach seat <NUM> in barrel <NUM>. Thus, the volume of bore <NUM> is reduced.

<FIG> shows a cross-sectional view of pressure relief valve <NUM> used in pumping mechanism <NUM> of <FIG>. Pressure relief valve <NUM> includes body <NUM>, plunger <NUM>, spring <NUM>, seat <NUM>, ball <NUM>, seals <NUM> and lever <NUM>. Body <NUM> is threaded into bore <NUM> of bracket <NUM> to engage bore <NUM>. Bore <NUM> extends into bracket <NUM> to engage pressure chamber <NUM> (<FIG>). Body <NUM> also includes transverse bore <NUM> which extends through body <NUM> to align with vent <NUM> in bracket <NUM>. Vent <NUM> receives return line <NUM> (<FIG>), which extends into fluid container <NUM> (<FIG>). As such a complete circuit is formed between fluid container <NUM>, suction tube <NUM>, pumping mechanism <NUM>, pressure chamber <NUM>, relief valve <NUM> and return line <NUM>. Plunger <NUM> is inserted into body <NUM> such that stem <NUM> extends through body <NUM> and flange <NUM> engages the interior of body <NUM>. Seal <NUM> is positioned between body <NUM> and flange <NUM> to prevent fluid from within bore <NUM> from entering body <NUM>. Spring <NUM> is positioned within body <NUM> and pushes against flange <NUM> to bias plunger <NUM> toward seat <NUM>. Ball <NUM> is positioned between plunger <NUM> and seat <NUM> to block flow between bore <NUM> and bore <NUM>. Seal <NUM> prevents fluid from leaking past ball <NUM>.

Valve <NUM> prevents pumping mechanism <NUM> from becoming over pressurized. Depending on the spring rate of spring <NUM>, plunger <NUM> will be displaced when pressure within pressure chamber <NUM> reaches a desired threshold level. At such level, bore <NUM> is connected with bore <NUM> to allow liquid within pressure chamber <NUM> to travel into vent <NUM>. Thus, the liquid is returned to container <NUM> and can be recycled by pumping mechanism <NUM>. For example, in one embodiment, valve <NUM> is configured to open at <NUM>,<NUM> psi (~<NUM> MPa), while valve <NUM> is configured to open at <NUM>,<NUM> psi (~<NUM> MPa). In various embodiments of the invention, plunger <NUM> can be provided with an adjustment mechanism to set the distance that plunger <NUM> is withdrawn from seat <NUM> so that valve <NUM> can be used to automatically or manually adjust flow of pumping mechanism <NUM>.

Valve <NUM> also provides a priming mechanism for pumping mechanism <NUM>. Upon initiating a new use of sprayer <NUM>, before fluid has filled pumping mechanism <NUM>, it is desirable to purge air from within sprayer <NUM> to prevent spitting or inconsistent spraying of fluid from tip <NUM>. As such lever <NUM>, which is connected to stem <NUM> by hinge <NUM>, can be pushed or pulled by an operator to withdraw ball <NUM> from engagement with seat <NUM>. Thus, upon activation of pumping mechanism <NUM>, air from within sprayer <NUM> is displaced by fluid from container <NUM> and purged from sprayer <NUM> through vent <NUM>. Thus, when lever <NUM> is released, valve <NUM> will open upon pressurization from fluid rather than pressurized air and the initial stream of atomized fluid will be consistent.

Valve <NUM> also provides a means for depressurizing sprayer <NUM> after use. For example, after operation of sprayer <NUM> when drive element <NUM> has ceased operating pumping mechanism <NUM>, pressurized fluid remains within sprayer <NUM>. It is, however, desirable to depressurize sprayer <NUM> such that sprayer <NUM> can be disassembled and cleaned. Thus, displacement of lever <NUM> opens valve <NUM> to drain pressurized fluid within pumping mechanism to container <NUM>.

<FIG> shows a cross-sectional view of a first embodiment of a fluid container <NUM> of <FIG>. Fluid container <NUM> comprises a generally cylindrical container <NUM> having lip <NUM> and contoured bottom <NUM>. Lip <NUM> is connected to sprayer <NUM> through threaded engagement with lid <NUM> of housing <NUM> (<FIG>). Bottom <NUM> is provided with base <NUM>, which is connected to container <NUM> to provide a flat bottomed surface upon which container <NUM> can rest while remaining upright. Suction tube <NUM> extends from pumping mechanism <NUM> into the interior of container <NUM>. In the embodiment shown, suction tube <NUM> comprises a fixed tube that reaches the bottom of container <NUM> near bottom <NUM>. Suction tube <NUM> is curved to reach the center of container <NUM>, where bottom <NUM> is flat. Suction tube <NUM> includes inlet <NUM>, which faces the flat portion of bottom <NUM>, and filter <NUM>. Inlet <NUM> extends over approximately the entire surface area of the flat portion of bottom <NUM>. Bottom <NUM> includes curved portion <NUM>, which funnels fluid within container <NUM> toward inlet <NUM>. As such, suction tube <NUM> is able to evacuate most of the volume of liquid provided in container <NUM> as sprayer <NUM> is disposed in an upright position.

<FIG> show cross-sectional views of a second embodiment of fluid container <NUM> of <FIG>. Fluid container <NUM> comprises a cylindrical container <NUM> having lip <NUM> and flat bottom <NUM>. Suction tube <NUM> extends into the interior of container <NUM>. In the embodiment shown, suction tube <NUM> comprises a two-piece tube having upper portion <NUM> and lower portion <NUM>. Upper portion <NUM> includes a curved portion to reach the center of container <NUM>. Lower portion <NUM> extends from upper portion <NUM> at an angle to reach bottom <NUM>. Lower portion <NUM> is rotatably attached to upper portion <NUM> such that inlet <NUM>, which includes filter <NUM>, can be disposed about the entire perimeter of cylindrical wall of container <NUM>. Lower portion <NUM> includes coupling <NUM> that fits over the lower end of upper portion <NUM>. Seal <NUM> is positioned between coupling <NUM> and upper portion <NUM> to prevent fluid from escaping tube <NUM>. As such, lower portion <NUM> can be rotated to a forward position as shown in <FIG> to spray, e.g. floors, in a downward orientation. Also, lower portion <NUM> can be rotated to an aft position as shown in <FIG> to spray, e.g. ceilings, in an upward orientation. Lower portion <NUM> can be rotated in a variety of manners. Lower portion <NUM> can be moved manually by an operator, such as before liquid is provided to container <NUM>. In another embodiment, a magnetic knob is provided on the bottom of container <NUM> to move inlet <NUM>.

<FIG> shows an exploded view of a second variation of a handheld sprayer, not covered by the appended claims. Spray gun 10B includes similar components as spray gun <NUM> of <FIG>, such as housing 12B, spray tip assembly 14B, fluid container 16B, pumping mechanism 18B, drive element 20B, relief valve 22B, battery 26B, guard 28B, spray tip 30B, valve 52B, gearing assembly 56B and connecting assembly 58B. Pumping mechanism 18B comprises a dual piston pumping assembly in which each piston is directly connected to container 16B and provides pressurized fluid to tip 14B. Pumping mechanism 18B includes first piston 72B and second piston 74B, both of which have the same displacement. Pistons 72B and 74B reciprocate within piston cylinders in housings <NUM> and <NUM> by direct coupling with connecting assembly 58B. Pistons 72B and 74B are reciprocate out of phase to reduce vibration and pulsation of liquid atomized by spray tip assembly 14B. Pistons 72B and 74B draw fluid from container 16B in through inlet valves <NUM> and <NUM>, respectively, which are disposed in housing <NUM>. Housing <NUM> includes inlet <NUM> which draws fluid from lower portion <NUM> of container 16B. Pistons 72B and 74B push fluid into outlet valves <NUM> and <NUM>, respectively, which are disposed in housing <NUM>. Housing <NUM> includes outlet <NUM> that connects to valve 52B. Valve 52B comprises a mechanically actuated valve that is connected to lever <NUM>. Lever <NUM> withdraws needle <NUM> from a valve seat within cylinder <NUM> to allow pressurized fluid into spray tip assembly 14B. Lever <NUM> is also electrically coupled to switch <NUM> that activates drive element 20B, which in the embodiment shown comprises an electric motor. Drive element 20B provides input power to pumping mechanism 18B through gearing assembly 56B, which provides a gear reduction function, and connecting assembly 58B, which converts rotational input power from drive element 20B to reciprocating linear motion for driving pistons 72B and 74B. For example, gearing assembly 56B may comprise a planetary gear set and connecting assembly 58B may comprise a wobble plate assembly. In another embodiment of the invention, piston 72B and piston 74B can be connected to different fluid containers to provide mixing within spray gun 10B.

<FIG> shows a cross-sectional assembled view of various components of spray gun 10B of <FIG>. Spray gun 10B includes spray tip assembly 14B, pumping mechanism 18B, shutoff valve 52B and connecting assembly 58B. As is discussed with reference to <FIG>, connecting mechanism <NUM> receives input from drive element 20B to provide power to pumping mechanism 18B. Pumping mechanism 18B is connected to shutoff valve 52B to control flow of pressurized fluid from pumping mechanism 18B to spray tip assembly 14B. Shutoff valve 52B and drive element 20B are both activated by actuation of lever <NUM>. Specifically, lever <NUM> is configured to pivotably rotate against housing 12B at rocker point P. Thus, retraction of the lower portion of lever <NUM>, such as by the hand of an operator, retracts rod <NUM> to pull pin <NUM> away from valve seat 184B to allow pressurized fluid into spray tip assembly 14B. Also, lever <NUM> is retracted to contact switch <NUM>, which is connected to drive element 20B to provide input power to pumping mechanism 18B. As such, mechanical actuation of lever <NUM> simultaneously activates drive element 20B and shutoff valve 52B.

Shutoff valve 52B comprises a mechanically actuated valve in which valve seat 184B is connected to cylinder <NUM> via connector 32B and cap 158B. Specifically, connector 32B is threaded onto cylinder <NUM> to sandwich valve seat 184B and bushing <NUM> between cap 158B and cylinder <NUM>. Spray tip assembly 14B also includes seals 299A and 299B which are positioned between seat 184B and bushing <NUM>, and bushing <NUM> and cap 158B, respectively. Guard 28B is connected to cap 158B. Guard 28B and cap 158B form bore 194B for receiving a spray tip assembly having a barrel, which includes a spray orifice for atomizing pressurized liquid. Thus, the spray tip assembly of the barrel and orifice can be inserted and removed from bore 194B easily, such as to change orifice size or clean the orifice. These spray tip assemblies are convenient and easy to manufacture. An example of such a spray tip assembly is described in <CIT>et al. , which is assigned to Graco Minnesota Inc. However, pressurized fluid must extend from seat 184B, across seal 199A, seal 199B and bushing <NUM>, and to the orifice within bore 194B before being atomized and discharged from spray tip assembly 14B, which has the potential to produce spitting. The area between seat 184B and the spray orifice can be reduced by incorporating the valve seat into the spray tip assembly barrel, as is described with reference to <FIG> and <FIG>.

<FIG> shows a perspective view of a third variation of a handheld sprayer embodiment of dispensing device <NUM> of <FIG> utilizing a gravity fed fluid container, not covered by the appended claims. Sprayer 10C includes housing 12C, spray tip assembly 14C, fluid cup 16C, pumping mechanism 18C and drive element 20C. Spray tip assembly 14C includes a pressure actuated valve that releases fluid pressurized by pumping mechanism 18C. Pumping mechanism 18C is provided with input power to pressurize a fluid from cup 16C by drive element 20C. Drive element 20C comprises an AC motor having power cable <NUM>, which can be plugged into any conventional power outlet, such as a <NUM> volt outlet. In other embodiments, drive element 20C can be configured to operate from about <NUM> volts to about <NUM> volts. However, any embodiment of the invention can be configured to operate on DC or AC power via a power cord or a battery. Pumping mechanism 18C and drive element 20C are integrated into housing 12C such that sprayer 10C comprises a portable handheld unit. Fluid cup 16C is mounted to the top of housing 12C such that fluid is fed into pumping mechanism 18C via gravitational forces. As such, sprayer 10C does not need suction tube <NUM> to draw fluid from cup 16C, as fluid is drained directly from cup 16C into an inlet of pumping mechanism 18C within housing 12C.

<FIG> shows a perspective view of a fourth variation of a handheld sprayer embodiment of dispensing device <NUM> of <FIG> utilizing a power drill as a drive element, not covered by the appended claims. Sprayer 10D includes housing 12D, spray tip assembly 14D, fluid cup 16D, pumping mechanism 18D and drive element 20D. Spray tip assembly 14D comprises a pressure actuated valve that releases fluid pressurized by pumping mechanism 18D. Pumping mechanism 18D is provided with input power to pressurize a fluid from fluid cup 16D by drive element 20D. Drive element 20D comprises a handheld drill. In the embodiment shown, the drill comprises a pneumatic drill that receives compressed air at inlet <NUM>. In other embodiments, however, the drill may comprise an AC or DC electric power drill. Pumping mechanism 18D includes a shaft that can be inserted into a chuck of the power drill to drive the pumping elements. Pumping mechanism 18D is integrated into housing 12D, while drive element 20D and fluid container 16D are mounted to housing 12D. Housing 12D also includes appropriate gear reduction to match speeds of the drill to those needed by pumping mechanism 18D to produce the desired pressures. Pumping mechanism 18D and fluid cup 16D are mounted to the drill using bracket <NUM>. Bracket <NUM> includes an anti-rotation mechanism that prevents pumping mechanism 18D from rotating with respect to drive element 20D when actuated by the drill. Bracket <NUM> also pivotably connects fluid cup 16D to the drill. Fluid cup 16D can be rotated on bracket <NUM> to adjust the angle at which fluid in cup 16D is gravity fed into housing 12D. In one embodiment, fluid cup 16D can be rotated approximately one-hundred-twenty degrees. As such, spray gun 16D can be used to spray in both upward and downward orientations.

<FIG> shows a perspective view of a fifth variation of a handheld sprayer embodiment of dispensing device <NUM> of <FIG> not covered by the appended claims and utilizing an arm bag fluid reservoir. Sprayer 10E includes housing 12E, spray tip assembly 14E, fluid cup 16E, pumping mechanism 18E and drive element 20E. Sprayer 10E comprises a similar sprayer as that of the embodiment of sprayer 10C of <FIG>. However, fluid container 16E comprises a flexible bag connected to housing 12E via tube <NUM>. The flexible bag comprises an enclosure similar to that of an IV (intravenous) bag and can be conveniently attached to an operator of sprayer 10E by strap <NUM>. For example, strap <NUM> can be conveniently attached to an upper arm or bicep of an operator. Thus, an operator need not directly lift the weight of fluid container 16E to operate sprayer 10E, thereby reducing fatigue.

<FIG> shows a perspective view of a sixth variation of a handheld sprayer embodiment of dispensing device <NUM> of <FIG> utilizing a hip pack fluid reservoir, not covered by the appended claims. Sprayer 10F includes housing 12F, spray tip assembly 14F, fluid cup 16F, pumping mechanism 18F and drive element 20F. Sprayer 10F comprises a similar sprayer as that of the embodiment of sprayer 10C of <FIG>. However, fluid container 16F comprises a rigid container connected to housing 12F via tube <NUM>. The container comprises an enclosure shaped to be ergonomically attached to an operator of sprayer 10F by belt <NUM>. For example, belt <NUM> can be conveniently attached to a torso or waist of an operator.

<FIG> shows a perspective view of a first variation of a hose-connected airless spray gun embodiment of dispensing device <NUM> of <FIG> utilizing a waist-mounted sprayer pack, not covered by the appended claims. Sprayer <NUM> includes housing <NUM>, spray tip assembly <NUM>, fluid cup <NUM>, pumping mechanism <NUM> and drive element <NUM>. Housing <NUM> of sprayer pack <NUM> is mounted to a waist of an operator by belt <NUM>. Housing <NUM> provides a platform upon which fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> are mounted. Spray tip assembly <NUM> is connected to pumping mechanism <NUM> via hose <NUM>. Hose <NUM> acts as an accumulator to dampen pulsation and vibration in the fluid pressurized by pumping mechanism <NUM>. Spray tip assembly <NUM> comprises an airless spray gun having mechanically actuated spray valve <NUM> that provides pressurized fluid to a spray orifice in ergonomically shaped handheld device <NUM>. Device <NUM> includes a trigger that opens valve <NUM>. Pumping mechanism <NUM> operates to pressurize fluid stored in container <NUM> and pump the pressurized fluid to device <NUM> through hose <NUM>. Pumping mechanism <NUM> is powered by drive element <NUM>, which comprises a cordless electric motor powered by battery <NUM>. Drive element <NUM> can be continuously operated by activating a switch located on housing <NUM>. In such an embodiment, a pressure relief valve or bypass circuit is provided in conjunction with pumping mechanism <NUM> until valve <NUM> is actuated by an operator. In another embodiment of the invention, device <NUM> includes a switch for operating drive element <NUM> through a cable running along hose <NUM>. The heavier, bulkier components of sprayer <NUM> are separated from device <NUM> such that an operator need not continuously lift all the components of sprayer <NUM> during operation. Fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> can be conveniently supported by belt <NUM> to reduce fatigue in operating sprayer <NUM>.

<FIG> shows a perspective view of a second variation of a hose-connected airless spray gun embodiment of dispensing device <NUM> of <FIG> utilizing a back-mounted sprayer pack, not covered by the appended claims. Sprayer <NUM> includes housing <NUM>, spray tip assembly <NUM>, fluid cup <NUM>, pumping mechanism <NUM> and drive element <NUM>. Sprayer <NUM> comprises a similar sprayer as that of the embodiment of sprayer <NUM> of <FIG>. However, drive element <NUM> comprises an AC electric motor having power cable <NUM> configured to be plugged into any conventional power outlet, such as a <NUM> volt outlet. Also, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> are integrated into housing <NUM> configured to be mounted onto a backpack arrangement. Housing <NUM> includes straps <NUM> that permit fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM> to be ergonomically mounted to a back of an operator. Thus, sprayer <NUM> is similar to that of sprayer <NUM>, but the backpack configuration increases the capacity of the fluid container. In other embodiments, drive element <NUM> operates using battery power to increase the mobility of sprayer <NUM>.

<FIG> shows a perspective view of a third variation of a hose-connected airless spray gun embodiment of dispensing device <NUM> of <FIG> utilizing a hopper-mounted sprayer pack, not covered by the appended claims. Sprayer 10I includes housing 12I, spray tip assembly 14I, fluid cup 16I, pumping mechanism 18I and drive element 20I. Sprayer 10I comprises a similar sprayer as that of the embodiment of sprayer <NUM> of <FIG>. However, fluid container 16I of sprayer 10I comprises a hopper. As such, an operator can quickly and easily setup sprayer 10I. Additionally, multiple operators can work off of a single container. The tray surface also provides a direct access point to liquid within container 16I to expand usage of sprayer 10I under different scenarios. For example, a roller can be rested on the tray surface of container 16I while using spray tip assembly 14I to eliminate the need for use of multiple containers. Also, liquid within container 16I can be used even when power to pumping mechanism 18I and drive element 20I is lost. Thus, container 16I reduces wasted fluid and clean up time in a variety of situations and manners. Furthermore, container 16I can be separated from housing 12I to enable easy cleaning of container 16I. Container 16I is designed to remain stationary while an operator moves about with device <NUM>. Thus, an operator need not carry container 16I to reduce fatigue and increase productivity. Fluid container 16I allows a large quantity of liquid to be stored to reduce refill times. Hose <NUM> is provided with extra length to increase the mobility of the operator.

<FIG> shows a perspective view of a first variation of a pail-mounted sprayer pack embodiment of dispensing device <NUM> of <FIG> utilizing a lid-mounted pump, not covered by the appended claims. Sprayer 10J includes housing 12J, spray tip assembly 14J, fluid cup 16J, pumping mechanism 18J and drive element 20J. Sprayer 10J comprises a similar sprayer as that of the embodiment of sprayer <NUM> of <FIG>. However, fluid container 16J comprises pail <NUM> having lid <NUM> upon which pumping mechanism 18J and drive element 20J are mounted. Drive element 20J comprises an AC electric motor having power cable <NUM> configured to be plugged into any conventional power outlet, such as a <NUM> volt outlet. Lid <NUM> is configured to be mounted on a standard five-gallon pail or a standard one-gallon pail to facilitate quick set up of spraying operations and to reduce waste. On operator of sprayer 10J need only open a fresh pail of paint and replace the lid with lid <NUM> of the present invention to begin operations. Pumping mechanism 18J is completely submerged in pail <NUM> to eliminate the need for priming. Also, the fluid within container 16J provides cooling to pumping mechanism 18J and drive element 20J.

<FIG> shows a perspective view of a second variation of a pail-mounted sprayer pack embodiment of dispensing device <NUM> of <FIG> utilizing a pump, not covered by the appended claims. Sprayer <NUM> includes housing <NUM>, spray tip assembly <NUM>, fluid cup <NUM>, pumping mechanism <NUM> and drive element <NUM>. Sprayer <NUM> comprises a similar sprayer as that of the embodiment of sprayer 10J of <FIG>. Pumping mechanism <NUM> comprises a handheld device, similar to that of device 10C of <FIG>, mounted to lid <NUM>. However, instead of feeding pumping mechanism <NUM> from a hopper, inlet <NUM> is connected to the interior of pail <NUM>. As such, inlet <NUM> connects to a feed tube that extends to the bottom of pail <NUM>. Prime valve <NUM> is disposed between the feed tube and inlet <NUM>. In other embodiments, pail <NUM> is pressurized to assist in feeding liquid to inlet <NUM>.

<FIG> shows a block diagram of dispensing device <NUM> of <FIG> utilizing an air-assist assembly, and not covered by the appended claims.

Device <NUM> comprises a portable airless spray gun comprising housing <NUM>, spray tip assembly <NUM>, fluid container <NUM>, pumping mechanism <NUM> and drive element <NUM>, as is described with reference to <FIG>. Device <NUM>, however, is also provided with air assist assembly <NUM>, which provides compressed air to spray tip assembly <NUM>. Air assist assembly <NUM> includes air line <NUM>, valve <NUM> and air nozzle <NUM>. Compressed air from air assist <NUM> is provided to spray tip assembly <NUM> through line <NUM>. Line <NUM> is provided with pressure valve <NUM> to limit the flow of air into spray tip assembly <NUM>. In one embodiment, air assist assembly <NUM> includes a compressor. For example, a small, portable, battery operated compressor can be used to provide air to spray tip assembly <NUM>. In another embodiment, air assist assembly <NUM> includes a tank or cartridge of compressed gas, such as CO<NUM>, Nitrogen or air. Spray tip assembly <NUM> is provides with air nozzle <NUM>, which comprises a passage within tip <NUM> that enables pressurized air from air assist assembly <NUM> to join with pressurized fluid from pumping mechanism <NUM>. In one embodiment, spray tip assembly <NUM> comprises a conventional air-assist spray tip, as are known in the art, that is further provided with an inlet for receiving externally pressurized air rather than internally pressurized air. Such an air-assist spray tip is described in <CIT>et al. , which is assigned to Graco Minnesota Inc. The compressed air helps push pressurized fluid generated by pumping mechanism <NUM> through spray tip assembly <NUM> to further atomize the fluid and provide an improved application of the fluid. Spray tip assembly <NUM> can be outfitted with a mechanism for adjusting the position of needle <NUM> in valve <NUM> to control the atomization of liquid. Also, orifice <NUM> can be configured, or replaced with another orifice, to optimize air assisted spraying. Thus, air assist assembly <NUM> increases the versatility of fluid dispensing device <NUM> to achieve more control over spray parameters and enable use with a wider variety of fluids.

<FIG> shows a perspective view of cart-mounted airless sprayer system <NUM> having storage receptacle <NUM> and battery charger <NUM> for portable handheld sprayer <NUM>, not covered by the appended claims. Cart-mounted airless sprayer system <NUM> is mounted to airless spray system <NUM>, which includes dolly cart <NUM>, motor <NUM>, pump <NUM>, suction tube <NUM>, hose <NUM> and spray nozzle <NUM>. Airless spray system <NUM> comprises a conventional airless spray system that is configured for large-scale industrial or professional use. System <NUM> includes heavy duty motor <NUM> and pump <NUM> that are designed for applying large volumes of liquid or paint during each use. Such a motor and pump are described in <CIT>et al. , which is assigned to Graco Minnesota Inc. For example, suction tube <NUM> is configured to be inserted into a five-gallon pail of paint that can be suspended from dolly cart <NUM> with hook <NUM>. Motor <NUM> is configured to be connected to a conventional power outlet using a power cord to provide input power to pump <NUM>. Spray nozzle <NUM> is connected to pump <NUM> using hose <NUM>, which provides ample length for an operator to roam. As such, system <NUM> comprises a portable spray system that can be wheeled around using cart <NUM> and then setup to remain stationary while an operator uses spray nozzle <NUM>. Thus, system <NUM> is well-suited for large jobs, but is inconvenient to move and re-setup, particularly for small jobs.

System <NUM> is provided with cart-mounted handheld spray system <NUM> to provide an operator with a convenient and quick system for complementing use of system <NUM>. Handheld spray system <NUM> is mounted to dolly cart <NUM> using receptacle <NUM>. Receptacle <NUM> comprises a container that is bolted or otherwise connected to cart <NUM>. Receptacle <NUM> comprises a holster for receiving sprayer <NUM>. In one embodiment, receptacle <NUM> comprises a molded plastic container shaped to firmly hold sprayer <NUM> and includes a hinged cover. Receptacle <NUM> is large enough to encase sprayer <NUM> as well as rechargeable battery 374A. Receptacle <NUM> also provides a platform on which to mount battery charger <NUM>. Battery charger <NUM> can be disposed inside of receptacle <NUM> or connected to the exterior of receptacle <NUM>. Battery charger <NUM> comprises an electric charger for re-energizing rechargeable batteries 374A and 374B. Battery charger <NUM> includes adapter <NUM> to which battery 374B is connected to be charged while battery 374A is in use with sprayer <NUM>. Battery charger <NUM> is provided with electric power through connection with the power cord that supplies power to motor <NUM>. Thus, battery charger <NUM> provides recharging capabilities so that batteries 374A and 374B are readily available for use in conjunction with spray system <NUM>.

Spray system <NUM> and sprayer <NUM> provide airless spray systems that provide high quality finishes. Spray system <NUM> is used for bulk application of a liquid or paint. Sprayer <NUM> is ready to be easily used by an operator in places or spaces where system <NUM> cannot reach due to, for example, limitations of the power cord or spray hose <NUM>. Sprayer <NUM> comprises any one of the embodiments of a portable airless sprayer described herein. As such sprayer <NUM> provides an airless spray finish that is commensurate in quality with the airless spray finish generated by spray system <NUM>. Thus, an operator can switch between using system <NUM> and sprayer <NUM> on a single job without noticeable differences in the spray quality.

The present invention, in its various embodiments, is able to achieve high quality sprayed finishes of architectural materials. For example, using a Dv(<NUM>) technique, where at least fifty percent of the sprayed droplets meet the atomization target, the present invention achieves atomization listed in the following table.

Thus, fluid dispensing devices of the present invention achieve orifice running pressures of approximately <NUM> psi (-<NUM> MPa) or greater in a handheld portable configuration, meeting Underwriters Laboratories® specification UL1450.

Claim 1:
A handheld airless sprayer (<NUM>) comprising:
a housing (<NUM>);
a reciprocating piston fluid pump (<NUM>) located within the housing and comprising at least one piston (<NUM>) configured to reciprocate to pressurize at least one pumping chamber (<NUM>, <NUM>);
an electric motor (<NUM>) located within the housing;
a wobble assembly (<NUM>) configured to convert a rotary input from the electric motor to reciprocating motion that reciprocates the at least one piston of the reciprocating piston fluid pump, the wobble assembly comprising:
a rotating rod (<NUM>) disposed within the housing (<NUM>) along a drive axis of rotation and configured to receive the rotary input from the electric motor (<NUM>);
a land (<NUM>); and
a connecting rod (<NUM>) joining the land with the at least one piston (<NUM>), wherein the land is disposed about the rotating rod (<NUM>) and has a cylindrical surface (<NUM>), which revolves about a wobble axis that is offset from the drive axis of rotation about which land (<NUM>) and rod (<NUM>) rotate, such that as the land (<NUM>) revolves, the axis of the cylindrical surface (<NUM>) orbits the axis of the rotating rod (<NUM>), making a cone-like sweep; and
a spray tip (<NUM>) downstream from the at least one pumping chamber;
wherein the electric motor (<NUM>) is configured to activate to move the wobble assembly (<NUM>) and reciprocate the at least one piston (<NUM>).