HK1084910A - Spraygun with built-in quick-fit connector for a paint reservoir - Google Patents

Description

Spray gun with built-in quick-fit coupling for paint reservoir

Technical Field

The present invention relates to improvements in or relating to liquid spraying apparatus such as spray guns. More particularly, the invention relates to a connection between a spray gun and a reservoir containing a liquid to be sprayed. The invention has particular, but not exclusive, application to releasable connections for removably mounting a reservoir on a spray gun and to spray guns adapted for such connections.

Background

Spray guns are widely used in vehicle body repair shops when repainting vehicles that have been repaired after an accident. In known spray guns, the liquid is contained in a reservoir connected to the spray gun from which it is delivered to the spray nozzle. From the nozzle, the liquid is atomized and a jet is formed by the compressed air supplied to the nozzle. The liquid may be gravity or suction delivered or (most recently) delivered to the spray gun by air release line pressure from the compressed air line to the reservoir.

Traditionally, the liquid is contained in a rigid tank that is mounted on the spray gun by complementary threaded connections on the tank and the spray gun. In this way, the canister may be removed for cleaning or replacement. Typically, the empty tank is secured to the spray gun and has a removable lid, by which liquid can be added to the tank attached to the spray gun. After the spray is complete, the canister can be removed and the spray gun and canister cleaned for reuse.

With this arrangement, the threads on the gun or canister may be damaged by misuse, such as attempting to secure a canister with a non-matching thread. Also, after the spray is completed, careful cleaning is required to remove all traces of liquid from the threads to prevent the threads from becoming clogged, for example, with dried paint, and to prevent cross-contamination with the next spray of liquid.

A damaged or blocked thread may render the gun unusable and a new gun may be purchased. This adds cost and inconvenience if working time is lost because a spare lance is not available in time to continue spraying. Also, cleaning the threads typically requires a solution that is also used to clean the spray gun and canister. The use of solutions is undesirable from health and safety considerations, and poses problems with post-use treatment solutions.

We have now developed a system in which the reservoir can be discarded after use, thereby reducing the amount of cleaning required after the spray is complete. For this system, the reservoir may be filled with the liquid to be sprayed before it is connected to the spray gun. Conventional threaded connections require the tank to make several turns, usually at least four or five turns, for fully engaging the threads and securing the tank in a fluid tight manner. This is time consuming and requires considerable care and skill by the user to prevent spillage when using the liquid filled reservoir.

To reduce these problems, we have proposed connecting the reservoir to the spray gun by means of an adapter which is screwed into the spray gun to provide a releasable quick-fit connection to the reservoir. For example, the reservoir and adapter may be provided with bayonet-type structures that are engageable with a push-and-twist action that requires less than a full rotation of the reservoir to connect the reservoir to the spray gun.

This arrangement enables the reservoir to be attached to and detached from the spray gun in a simple and effective manner which reduces the risk of spillage when the reservoir is filled with liquid and which requires less skill on the part of the user.

The provision of the adapter enables existing spray guns having a threaded connection for use with conventional rigid reservoirs to be converted for use with our system using a disposable reservoir. This has a number of advantages for the user, in particular a reduction in the cleaning effort required after the spraying has been completed. However, problems arise if an adapter having threads that mate with the threads on the spray gun is not available, for example if the adapter is removed for cleaning and lost. If the user does not have a stock adapter or a rigid reservoir that can be threaded into the spray gun without an adapter, the spray gun cannot be used with a disposable reservoir and can waste working time. Also the threaded connection between the spray gun and the adapter is prone to damage by misuse in the same way as the connection between the spray gun and the reservoir may render the spray gun unusable.

Disclosure of Invention

The present invention has been made keeping in mind the above problems and disadvantages associated with the prior art structures for securing a reservoir to a spray gun.

More particularly, at least certain embodiments of the present invention provide an improved connection between a spray gun and a reservoir that enables the reservoir to be attached and detached from the spray gun in a simple manner and reduces the risk of damage to the spray gun.

Also, at least one embodiment of the present invention provides for this improved connection between the spray gun and the reservoir, which allows the reservoir to be directly connected to the spray gun without the addition of separate components that may be lost and/or may not be compatible with the connection on the spray gun and reservoir.

Moreover, at least one embodiment of the present invention provides a spray gun adapted for quick, releasable attachment to a reservoir, which enables the reservoir to be attached when full of liquid with little risk of spillage and without requiring a high degree of user skill with respect to attaching/detaching the reservoir.

Further, at least one embodiment of the present invention provides a spray gun provided with an integral adapter for removably mounting a reservoir having a matable adapter and an adapter for converting the spray gun adapter to releasably mount a reservoir having a non-matable adapter in a simple manner.

In addition, at least one embodiment of the invention provides a spray gun provided with an integral fitting for removably mounting a reservoir that incorporates the functions of a cover for closing the orifice end of the reservoir and a fluid fitting for delivering liquid from the reservoir to the spray gun in use.

Further, at least one embodiment of the present invention provides an insert for converting a socket for an integral, threadless adapter on a spray gun into a receptacle for mounting a reservoir having an adapter that is non-matable with the adapter socket and compatible with the insert.

Thus, according to one aspect of the present invention there is provided liquid spraying apparatus comprising a spray gun and a reservoir for liquid to be sprayed, the reservoir having an outlet connectable to the spray gun to allow liquid to be drawn from the reservoir in use, the spray gun having integral connector means arranged for threadless engagement with co-operating connector means on the reservoir by which means the reservoir is releasably secured to the spray gun.

As used herein, the term "liquid" refers to all forms of flowable materials that can be applied with a spray gun (which may or may not be used to color a surface), including, without limitation, paints, primers, basecoats, lacquers, varnishes, and similar paint-like materials, as well as other materials such as adhesives, sealants, fillers, putties, powder coatings, blasting powders, abrasive slurries, mold release agents, and cast overlays, which may be applied in mists or mists, depending on the nature and/or use of the material, and thus the term "liquid" is interpreted.

According to the invention, the spray gun is provided with an integral threadless fitting for mating engagement with a cooperating threadless fitting on the reservoir. In this way, the above-mentioned problems and disadvantages of a threaded connection between the reservoir and the spray gun are avoided, enabling the reservoir to be releasably secured to the spray gun in a simple manner facilitating rapid attachment/detachment of the reservoir.

As used herein, the term "threadless engagement" refers to all forms of releasable connection that can be engaged/disengaged between two couplings by relative axial movement and/or by relative angular movement involving less than a full rotation about a connection axis.

In a preferred construction, the spray gun has an integral socket adapted to connect to the outlet of the reservoir. The socket provides a through-hole to the inlet of the spray gun with which the outlet of the reservoir communicates in a fluid tight manner when the reservoir is connected to the spray gun, delivering liquid to the spray gun in use.

The socket may be recessed within the body of the spray gun. More preferably, however, the socket is provided in an adaptor boss which is arranged to project from the body of the spray gun. In this way, the socket is clear of the body of the spray gun, providing an improved passage for the reservoir connection.

The joint boss may be formed integrally with the lance body. For example, the body and boss may be a casting or moulding of a metal or alloy. Alternatively, the adapter boss may be formed separately from the spray gun body and permanently secured to one another. For example, the joint boss may be welded or bonded to the spray gun body.

In one embodiment, the outlet of the reservoir opens into a connecting tube integral with the reservoir and which is received within the socket to connect the reservoir to the spray gun. For example, the connection pipe may be provided at one end of the storage tank. In an embodiment, the tank has a detachable lid at the end where the connection tube is provided.

The reservoir and the spray gun may be provided with matable structures that provide a push-fit connection of the reservoir to the spray gun. For example, the connecting tube and socket may be tapered such that the connecting tube is an interference friction fit within the socket for retaining the reservoir on the spray gun.

Alternatively, the reservoir and the lance may be provided with cooperating structures engageable by a push-twist action requiring less than a full rotation of the reservoir relative to the lance.

In one arrangement, the connection tube and the socket are provided with a bayonet type arrangement engageable in the bore of the socket. For example, the connection tube may be provided with one or more outwardly extending bayonet projections or lugs which may cooperate with one or more bayonet grooves on the wall of the bore of the socket. The or each bayonet recess may have an axially extending guide portion for receiving an aligned projection or lug portion and leading to a circumferentially extending retaining portion for gripping and retaining the projection or lug portion so as to secure the reservoir to the spray gun.

In another arrangement, the spray gun and reservoir are provided with mating formations engageable outside the bore of the socket. For example, the reservoir may be provided with one or more hook portions separate from the connecting tube, the hook portions being arranged to engage the spray gun for releasably securing the reservoir and preventing axial separation of the connecting tube from the socket.

The or each hook portion may preferably be located on a surface of the outer flange of the connecting tube. For example, the flange may have a recess arranged to allow passage of the aligned hook portions and an adjacent cam projection arranged to resiliently deflect the hook portions as the reservoir is rotated causing the distal ends of the hook portions to sit on the surface of the flange to retain the reservoir on the spray gun.

The flange may be provided with a stop portion to limit rotation of the fixed reservoir relative to the reservoir of the spray gun to less than 360 degrees. For example, the stop portion may provide a quick-fit connection using a half-turn or a quarter-turn of the reservoir relative to the spray gun. The stop portion may comprise an abutment surface which is contacted by the or each hook portion.

Alternatively, the reservoir may be provided with external ribs on the connecting tube which are cooperable with the spray gun externally of the socket for releasably securing the reservoir and preventing axial separation of the connecting tube from the socket. The rib may preferably be located under a radial projection or spigot on the spray gun by inserting the connector tube into the socket and rotating the reservoir relative to the spray gun for less than one full rotation. In a modified structure, the rib may be provided on the spray gun and the protrusion may be provided on the connection pipe.

The rib may have a spiral shape providing a ramp cooperable with the projection for axially moving the connecting tube into the socket by contact of the rib with the projection. The ribs and projections are arranged to secure the reservoir to the gun by rotation of less than 360 degrees relative to the gun. The ribs may extend circumferentially about 180 degrees.

Preferably, a stop portion is provided for limiting rotation of the reservoir relative to the spray gun. In this way, the joint is prevented from being over-tensioned, controlling the axial movement of the connecting tube into the socket, ensuring a fluid-tight connection. The stop portion may comprise an abutment portion at one end of the rib which may contact the projection to prevent rotation of the reservoir relative to the spray gun. Alternatively, the stop portion may comprise a second rib axially spaced from the helical rib and contactable with the projection or spray gun body to prevent axial movement of the connecting tube into the socket.

A fluid tight seal may be provided by an interference fit of the connecting tube within the socket. The interference fit may be facilitated by providing one or more annular sealing ribs on the connecting tube. In another aspect, the socket and/or the connecting tube may be provided with one or more sealing rings, such as o-rings, arranged to provide a fluid tight seal.

In another embodiment, the sidewall of the reservoir defines an aperture at an end of the reservoir defining the outlet, the end of the sidewall being received within the socket of the spray gun to connect the reservoir to the spray gun. In this embodiment, the adapter boss of the spray gun may be provided with an enlarged head forming a socket and forming a lid for the reservoir.

In this way, the orifice end of the reservoir is closed when the reservoir is connected to the spray gun, and a separate, removable cover for the reservoir is not required. Thus, the number of parts for assembling the reservoir can be reduced, and the reservoir-to-spray gun connection can be simplified.

In one arrangement, the socket preferably has an annular seat around the aperture contactable with an end of the side wall. The end of the sidewall may be located and retained within the socket by an interference push fit to releasably secure the reservoir within the socket.

In other words, the side wall and the socket may be provided with complementary threadless connector means. The threadless connector means may comprise any of the arrangements described above, for example a mating arrangement engageable on the inside or outside of the socket by a push-twist action, such as a bayonet arrangement.

The reservoir may be reusable. For example, the reservoir may comprise a rigid canister that is removable from the spray gun and cleaned after spraying is complete. Typically, the canister has an openable vent at the end remote from the connection to the spray gun to allow air to enter as liquid is drawn from the canister in use.

More preferably, the reservoir is disposable. For example, the tank may include an outer container and a liner that is collapsible and separable from the outer container as liquid is pumped from the tank so that the tank may be removed and the liner discarded after use. Typically, the outer container is vented away from the end connected to the spray gun to allow air to enter as liquid is drawn from the liner in use.

The above-described socket on the spray gun may be provided with an insert for converting the socket into a connection with a reservoir having a non-matable connector. In this way, the spray gun can be adapted in a simple and effective manner to the installation of tanks provided with different connections. A set of interchangeable inserts may be provided to allow attachment of any selected one of the inserts to provide any desired connector means to the socket. Preferably, the insert is a plastic moulding, but other materials including metal may be used. Typically, the insert is a nylon molded part.

In one arrangement, the spray gun is provided with an integral retaining formation external to the socket so that a reservoir provided with a matable retaining formation can be located and secured to the spray gun by a push-twist action requiring less than a full rotation of the reservoir relative to the spray gun, and the insert enables the spray gun to be adapted for connection to a socket provided with a conventional threaded fitting or other type of fitting which is not matable with the integral retaining formation on the spray gun.

The insert may be provided with retaining structure which is cooperable with retaining structure on the spray gun to locate and retain the insert. For example, the insert may be provided with external ribs which are cooperable with retaining formations on the spray gun externally of the socket for releasably securing the insert and preventing axial separation of the insert from the socket.

The retaining formation may comprise a radial projection or projection and the rib may be located on the underside by placing the insert in the socket and rotating the insert relative to the spray gun through less than a full turn. In this way, the insert may be used to position and retain the reservoir, preventing inadvertent or accidental separation of the reservoir from the socket.

The rib may have a spiral shape providing a ramp surface that is cooperable with the protrusion such that the insert is axially displaced into the socket by contact of the rib and the protrusion. The rib and projection are arranged such that the insert can be secured to the lance by less than 360 degrees of rotation relative to the lance. The ribs may extend circumferentially about 180 degrees. In a modified arrangement, the ribs may be provided on the lance and the projections may be provided on the insert.

Preferably, a stop portion is provided for limiting rotation of the insert relative to the spray gun. In this way, the coupling is prevented from over-tensioning and axial movement of the control insert into the socket is ensured to achieve a fluid tight connection. The stop portion may comprise an abutment portion at one end of the rib which is contactable with the projection for preventing rotation of the insert relative to the spray gun. Alternatively, the stop portion may comprise a second rib axially spaced from the helical rib and contactable with the projection or spray gun body to block axial displacement of the insert into the socket.

In another aspect, the insert may be configured to block or surround an integral retaining structure on the spray gun so that it does not interfere with the connection to the reservoir. For example, the insert may be provided with a recess into which the retaining formation on the spray gun is received by a push fit of the insert within the socket. The recess may be provided in a flange arranged to extend on either side of the retaining structure for limiting rotation of the insert relative to the spray gun. In this configuration, the insert is preferably an interference fit within the socket to reduce inadvertent or accidental separation of the insert (and attached reservoir) from the socket.

A spray gun with an integral threadless connector may also have utility in connection with providing a connection to a remote reservoir through a supply line, such as tubing, with a suitable matable connector for connection to a socket or to an insert for converting the socket into a connector for accepting a non-matable connector.

Thus, according to another aspect of the invention, there is provided a spray gun with an integral socket for connection to a reservoir provided with a matable coupling and a removable insert for converting the socket into a connection to a reservoir provided with a non-matable coupling.

The socket may be adapted for threadless connection to the reservoir, while the insert is arranged to convert the socket into a threaded connection to the reservoir.

According to yet another aspect of the present invention, a spray gun is provided having an integral threadless connector for mating engagement with a threadless connector on a reservoir to releasably connect the reservoir to the spray gun.

The threadless connection on the spray gun and the reservoir may comprise a socket on one of the spray gun and the reservoir adapted to receive a mating structure on the other of the spray gun and the reservoir.

In one arrangement, a socket is provided on the spray gun and has an internal bore providing an inlet connectable to the outlet of the reservoir. In this configuration, the outlet of the reservoir may be provided by a connecting tube received in an aperture of a socket on the spray gun.

The socket may be recessed within the body of the spray gun, but more preferably the spray gun has a fitting boss which projects from the spray gun body in which the socket is formed.

A connector is engageable within the bore of the receptacle for releasably connecting the reservoir to the spray gun. Alternatively, the contacts may engage outside the receptacle holes for releasably connecting the receptacle to the spray gun.

According to a further aspect of the invention there is provided a method of connecting a reservoir to a spray gun comprising providing a spray gun body with an integral unthreaded fitting, providing a reservoir with an unthreaded fitting which is mateable with the fitting of the body, and connecting the two fittings to releasably secure the reservoir to the spray gun.

Preferably, the two connectors are engageable by a push-twist action which requires less than a full rotation of the reservoir to secure the reservoir to the lance. For example the connector may be of the bayonet type.

According to a further aspect of the invention, there is provided liquid spraying apparatus comprising a spray gun and a reservoir for liquid to be sprayed, the reservoir being releasably connectable to the spray gun by a quick-fit connection system which utilises mateable fittings on the spray gun and the reservoir, wherein the spray gun has a body and the spray gun fitting is integral with the spray gun body.

Preferably, the lance and the reservoir form a connection axis when the reservoir is secured to the lance. The engageable couplings may be engaged/disengaged by relative axial movement substantially parallel to the axis of connection. Alternatively, the matable couplings may be engaged/disengaged by a combination of relative axial movement substantially parallel to the axis of connection and angular movement about the axis of connection of less than 360 degrees.

According to a further aspect of the present invention there is provided liquid spraying apparatus comprising a spray gun and a reservoir for liquid to be sprayed, the reservoir having a side wall extending from a first end to a second end and defining an orifice at the first end, the spray gun having an integral inlet fitting with an enlarged head, the fitting being cooperable with the first end of the reservoir such that the orifice is sealed in a fluid tight manner with respect to the head.

The enlarged head of the inlet fitting forms a lid for the reservoir. In this way, the orifice end of the reservoir is closed when the reservoir is connected to the spray gun, and a removable lid for the reservoir is not required. Thus, the number of parts for tank assembly can be reduced and tank-to-gun connection is simplified.

In one configuration, the head forms a socket that receives the first end of the canister. The socket preferably has an annular seat surrounding the aperture accessible to the first end of the reservoir.

The first end of the reservoir may be located and retained within the socket by a threaded or unthreaded fitting. In one arrangement, the socket and the reservoir are provided with complementary screw threads for releasably securing the reservoir. In another arrangement, the reservoir is an interference push fit within the socket for releasably securing the reservoir. In yet another arrangement, the reservoir and the socket are provided with complementary threadless connector means engageable either internally or externally of the socket.

The inlet fitting may be integrally formed with the lance, for example by casting or moulding. Alternatively, the inlet fitting may be separately formed and permanently affixed to the spray gun, such as by welding or adhesive.

The storage tank may comprise a rigid canister with an openable vent at the second end, the vent allowing air to enter as liquid is drawn from the storage tank in use. More preferably, the tank comprises an outer container and a liner, the liner being collapsible and separable from the outer container as liquid is pumped from the tank, whereby the liner can be removed and discarded after use.

Other features, benefits and advantages of the present invention within aspects of the invention will be apparent from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings.

Brief Description of Drawings

FIG. 1 is a perspective view of a liquid ejection apparatus embodying the present invention;

FIG. 2 is a perspective view of the reservoir shown in FIG. 1, separated from the spray gun;

FIG. 3 is a longitudinal section through the tank shown in FIG. 2;

FIG. 4 is a perspective view of the spray gun of FIG. 1, separated from the reservoir;

FIG. 5 is an exploded perspective view showing details of the connection between the spray gun and the reservoir shown in FIGS. 1 to 4;

FIG. 6 is an end view of the adapter boss of the spray gun with portions removed for clarity;

FIG. 7 is an exploded perspective view of another connection between the spray and the reservoir embodying the present invention;

FIG. 8 is a cross-sectional view through the assembled connection of FIG. 7;

FIG. 9 is an exploded perspective view of another connection between the spray gun and the reservoir embodying the present invention;

FIG. 10 is a cross-sectional view through the spray gun socket shown in FIG. 9;

FIG. 11 is a perspective view of a spray gun with yet another integral adapter in accordance with the present invention;

FIG. 12 is an enlarged cross-sectional view showing the reservoir connected to the integral joint of FIG. 11;

FIG. 13 is a sectional view similar to FIG. 12 of a modification of the reservoir;

FIG. 14 is a perspective view of a spray gun with an integral adapter according to the present invention and a removable insert for converting the adapter to receive a threaded adapter for connection to a reservoir;

FIG. 15 is a perspective view showing a threaded fitting attached to the spray gun of FIG. 14;

FIG. 16 is a perspective view showing the reservoir connected to the spray gun of FIGS. 14 and 15;

FIG. 17 is a cross-sectional view of the integral fitting and insert of the spray gun depicted by FIG. 14 showing the threaded fitting of FIG. 15 separated from the insert;

FIG. 18 is a perspective view of a spray gun illustrating a modification of the fitting of FIG. 11 in accordance with another aspect of the present invention;

FIG. 19 is an enlarged cross-sectional view showing the reservoir connected to the integral joint of FIG. 18;

FIG. 20 is a cross-sectional view through an inlet aperture in the body of a gravity feed spray gun provided with an external retaining structure;

FIG. 21 is a perspective view of an insertion adapter for the entry hole shown in FIG. 20;

FIG. 22 is a plan view of the insert adapter shown in FIG. 21;

FIG. 23 is a side view of the insertion adapter shown in FIG. 21;

FIG. 24 is a cross-sectional view of the insertion adapter shown in FIG. 21;

FIG. 25 shows the insert adapter of FIGS. 21 to 24 installed in the inlet of the spray gun body of FIG. 20;

FIG. 26 is a perspective view of another insertion adapter for the inlet aperture shown in FIG. 20;

FIG. 27 is a plan view of the insert adapter shown in FIG. 26;

FIG. 28 is a side view of the insertion adapter shown in FIG. 26;

FIG. 29 is a cross-sectional view of the insertion adapter shown in FIG. 26;

FIG. 30 is a perspective view of yet another insertion adapter for the entry hole shown in FIG. 20;

FIG. 31 is a plan view of the insert adapter shown in FIG. 30;

FIG. 32 is a side view of the insertion adapter in the direction of arrow A shown in FIG. 31;

FIG. 33 is a cross-sectional view of the insert adapter shown in FIG. 30;

FIG. 34 is a cross-sectional view showing the insert adapter of FIGS. 30 to 33 installed within the inlet bore of the spray gun body shown in FIG. 20;

FIG. 35 is a perspective view of another insertion adapter for the inlet aperture shown in FIG. 20;

FIG. 36 is a plan view of the insert adapter shown in FIG. 35;

FIG. 37 is a side view of the insertion adapter in the direction of arrow B shown in FIG. 36;

FIG. 38 is a side view of the insertion adapter in the direction of arrow C shown in FIG. 36;

FIG. 39 is a cross-sectional view of the insertion adapter shown in FIG. 35;

FIG. 40 is a perspective view of yet another insertion adapter for the entry hole shown in FIG. 20;

FIG. 41 is a plan view of the insert adapter shown in FIG. 40;

FIG. 42 is a side view of the insertion adapter in the direction of arrow D shown in FIG. 41;

FIG. 43 is a side view of the insertion adapter in the direction of arrow E shown in FIG. 41;

FIG. 44 is a cross-sectional view of the insert adapter shown in FIG. 40;

FIG. 45 is a perspective view of a reservoir with an integral outlet suitable for connection to the spray gun of FIG. 20;

FIG. 46 is a side view of the storage tank shown in FIG. 45;

FIG. 47 is a longitudinal cross-sectional view of the reservoir shown in FIG. 45;

FIG. 48 is a perspective view of a reservoir cap with an integral outlet adapted for connection to the spray gun of FIG. 20;

FIG. 49 is a side view of the reservoir cap shown in FIG. 48;

FIG. 50 is a longitudinal cross-sectional view of the reservoir cap shown in FIG. 48;

FIG. 51 is a side view of a modification of the insert of FIGS. 21 to 24; and

fig. 52 is a side view of a modification of the insert of fig. 26 to 29.

Detailed Description

Referring initially to figure 1 of the drawings, there is shown a liquid spraying apparatus embodying the present invention which comprises a gravity feed spray gun 1 and a reservoir 2 removably connected to the spray gun 1.

The spray gun 1 comprises a body 3, a handle 4 extending downwardly from the rear end of the body and a nozzle 5 at the front end of the body. The spray gun 1 is manually operated by a trigger 6 pivotally mounted on the side of the spray gun.

A reservoir 2 containing paint (or similar material) to be ejected by the spray gun is located on top of the body 3 and communicates with an internal passage (not visible) extending through the spray gun to the nozzle 5.

In use, the spray gun 1 is connected to a source of compressed air (not shown) by a connection 7 at the lower end of the handle 4, so that when a user pulls on the trigger 6, compressed air is delivered through the spray gun to the spray nozzle 5. Thus, the paint delivered under gravity from the reservoir 2 to the nozzle 5 forms a mist on leaving the nozzle 5 and forms a jet with the compressed air coming out of the nozzle 5.

Referring now to fig. 2 and 3 of the drawings, the reservoir 2 comprises an outer container 8, a disposable liner 9, a disposable lid 10 and a collar 11. The liner 9 corresponds in shape to (and is a close fit within) the interior of the vessel 8 and has a narrow flange 12 at the open end which sits on the top edge of the vessel 8.

The lid 10 is conical and has a depending skirt 13 inset from the periphery. The skirt 13 is push-fitted over the orifice end of the liner 9 to place the periphery of the lid 10 over the flange 12 of the liner 9. The lid/liner assembly is held in place by an annular web 11 on top of the lid 10 that is threaded onto the container 8.

The cap 10 has a central hole 14 at the top end which opens into a connecting tube 15 to provide a fluid outlet, and a pair of hook portions 16, 17 on either side of the connecting tube 15. The hook portions 16, 17 are arranged to releasably secure the reservoir 2 to the spray gun 1 and the tube 15 is formed with an outer annular rib 18 to provide a fluid tight seal with the spray gun 1 as described below.

The mesh filter element 19 is press fitted within the skirt 13 and in use removes particulate material from paint delivered to the spray gun 1 via the tube 15. Alternatively, filter element 19 may be press fit within tube 15 or may be an integral part of cap 10.

Referring now to figures 4 to 6, the spray gun 1 is provided with an integral adapter nose 20 on the top of the body 3. The projection 20 extends upwardly from the body 3 and has a socket 21, the socket 21 being shaped to receive the connecting tube 15 on the lid 10 of the reservoir 2. The socket 21 terminates in an internal shoulder 33 leading to an aperture 34, the aperture 34 extending away from the socket 21 and providing an inlet for the transfer of paint from the reservoir 2 to the spray gun 1.

In this embodiment, the projection 20 is formed integrally with the body 3 of the lance 1, for example, the body 3 may be a casting of a lightweight metal or alloy. Alternatively, the projection 20 may be formed separately and permanently fixed to the body 3, for example by welding, so as to form an integral part of the spray gun 1.

The outer ribs 18 of the connection tube 15 provide a fluid tight seal with the socket 21 and the projection 20 has an outer flange 22 at the distal end for cooperating with the hook portions 16, 17 to releasably secure the reservoir 2 to the spray gun 1. In another embodiment (not shown), a fluid tight seal may be obtained by one or more sealing rings, such as o-rings, located in grooves on the connecting tube 15 or in the wall of the socket 21.

The flange 22 includes four arcuate recesses 23, 24, 25, 26 (fig. 6) evenly spaced circumferentially around the periphery such that the recesses 23, 25 are opposite one another and the recesses 24, 26 are opposite one another.

Each recessed portion 23, 24, 25, 26 leads in a clockwise direction (as viewed in fig. 6) through a cam lobe 23a, 24a, 25a, 26a at the end of the recessed portion 23, 24, 25, 26 to a straight portion 27, 28, 29, 30 terminating in an abutment 27a, 28a, 29a, 30 a.

Each hook portion 16, 17 comprises an enlarged head 31, 32 at the distal end having an inclined face 31a, 32a leading to an undercut locking flange 31b, 32b for cooperation with the flange 22.

To secure the reservoir 2 to the spray gun 1, the hook portions 16, 17 are aligned with a pair of opposed recesses 23, 25 or 24, 26 in the flange 22. The connecting tube 15 is then pushed into the socket 21 so that the enlarged heads 31, 32 of the hook portions 16, 17 pass through the aligned recesses 23, 25 or 24, 26.

The reservoir 2 is then rotated relative to the spray gun 1 causing the hook portions 16, 17 to bear against the cam lobes 23a, 25a or 24a, 26a and the locking flanges 31b, 32b to be located behind the straight portions 27, 29 or 28, 30. The contact of the hook portions 16, 17 with the abutment portions 27a, 29a or 28a, 30a limits the rotation of the reservoir 2.

In this way, the reservoir 2 can be secured to the spray gun 1 by a push-and-twist action which requires less than one rotation of the reservoir 2 relative to the spray gun 1 about the connection axis formed by the engagement of the connection tube 15 within the socket 21. In this embodiment, the reservoir is rotatable through about a quarter turn or less for securing the reservoir to the lance.

The reservoir 2 can be removed from the spray gun 1 by a reverse operation in which the reservoir 2 is first rotated to align the enlarged heads 31, 32 of the hook portions 16, 17 with the opposed recessed portions 23, 25 or 24, 26. The reservoir 2 is then pulled to pull the connection tube 15 out of the socket 21.

When the reservoir 2 is rotated relative to the spray gun 1 to attach and detach the reservoir 2, the hook portions 16, 17 are deflected outwards and pressed backwards by the cam projections 23a, 25a or 24a, 26a coming into contact with them. In this way, when connected to the spray gun 1, the reservoir 2 is reliably held in place whilst the spray gun 1 is operated to apply paint to a surface.

The reservoir 2 can also be assembled to the spray gun 1 by a simple push fit which is first performed by aligning the hook portions 16, 17 with a pair of opposed straight portions 27, 29 or 28, 30 of the flange 22. The reservoir 2 is then pushed towards the spray gun 1 causing the inclined surfaces 31a, 32a to engage the flange 22. Due to the resiliency of the hook portions 16, 17 against the flange 22, the enlarged heads 31, 32 deflect outwardly, and are compressed back after passing the flange 22, so that the locking flanges 31b, 32b are behind the flat portions 27, 29 or 28, 30. In this way, the reservoir 2 is fixed to the spray gun 1. By reversing the operation, the tank 2 can be disassembled if sufficient force is applied to release the locking flanges 31b, 32 b.

In use, the reservoir 2 is filled with paint (or other liquid to be sprayed) before it is mounted on the spray gun 1. For this purpose, the liner 9 is pushed into the interior of the container 8. The paint is then poured into the liner 9, if necessary mixed with other colorants, film hardeners and diluents (solvents). The cap 10 is then pushed into place and screwed down into the collar 11 to hold the cap 10 tightly in place.

The spray gun 1 is then inverted from its normal operating position shown in figure 1 so that the reservoir 2 can be brought into an upright position relative to the spray gun 1 to prevent paint spillage. The reservoir 2 is then secured to the lance 1 by a push-twist or push action as described above.

The lance 1 can then be returned to its normal operating position for use in the usual manner. The liner 9 collapses axially from the base end 9a towards the lid 10 as paint is withdrawn from the reservoir. A vent hole 8a in the base end of the container 8 allows air to enter the container 8 as the liner 9 collapses. When the liner 9 collapses, the sidewalls 9b of the liner 9 fold inward in a random, uncontrolled direction.

After use, when the spray gun 1 is to be cleaned, the spray gun 1 can be turned upside down again from its working position shown in fig. 1. With the air tube removed, the trigger 6, which is simply actuated, allows paint in the spray gun 1 to empty into the liner 9 in the reservoir 2. The reservoir 2 is then detached from the spray gun 1 as described above.

As will be appreciated, the integral structure on the lance 1 and the reservoir 2 allows the reservoir 2 to be attached to and detached from the lance 1 with a simple action. In this way, the device can be assembled and disassembled quickly and easily, using the simplest manual techniques of the user. Also, the risk of spillage when connecting the reservoir 2 containing paint to the spray gun 1 is reduced. Moreover, the reservoir 2 can be removably secured to the spray gun without a separate adapter and without the need for connecting threads that could be damaged by misuse or clogging due to deposited paint, rendering the spray gun unusable.

When the tank 2 is removed from the gun 1, the tank 2 can be disassembled by removing the collar 11 and pulling the lid 10 and pulling the collapsed liner 9 with the lid, for example by sealing the connecting tube 15 using a removable closure cap (not shown) to preserve the paint remaining in the liner 9 for a short period of time. The lid/liner assembly can then be reassembled with the container 8 and collar 11 and reconnected to the spray gun 1 to use the remaining paint.

The lid/liner assembly is relatively vulnerable to damage when removed from the container 8, and the liner 9 and lid 10 are easily separated if not handled properly. Therefore, it is common practice to store the unused paint for only a few hours, and if long-term storage is required the unused paint must be poured into another container.

When all of the paint is used up or if any remaining paint is no longer required, lid 9 (including filter 19) and collapsed liner 9 can be discarded, container 8 and collar 11 cleaned and prepared for use with a new liner 9 and lid 10. In this way, only the spray gun 1 itself needs to be cleaned. Therefore, an effect of reducing the amount of solvent used for cleaning can be achieved.

Referring now to fig. 7 and 8, another arrangement for removably securing the reservoir to the spray gun is shown. For convenience, like reference numerals in the series 100 are used to designate parts corresponding to the above embodiments.

In this embodiment, the hook portion of the previous embodiment is omitted and the reservoir 102 is releasably secured to the spray gun 101 by an interference friction fit between the connection tube 115 of the reservoir 102 and the socket 121 of the spray gun 101.

As shown, the connection tube 115 on the cap 110 of the reservoir 102 is tapered to narrow distally, and the socket 121 of the adapter nose 120 is tapered for an interference friction fit of the tube 115 within the socket 121. In this manner, the reservoir 102 is secured to the lance 101 by a push fit.

The interference friction fit of the tube 115 provides a fluid tight seal with the receptacle 121. If desired, one or more sealing rings (not shown) may be placed in grooves in the tube 115 or the receptacle 121 to improve the sealing therebetween. The or each sealing ring is pressurised by the push-fit of the tube 115 and also helps to retain the tube 115 within the socket 121.

In other respects, the structure of the tank 102 is generally similar to the above embodiment, and need not be further explained, as will be understood from the description thereof.

Referring now to fig. 9 and 10, yet another arrangement is shown with respect to releasably securing the reservoir to the spray gun. For convenience, like reference numerals in the series 200 are used to indicate parts corresponding to the embodiments described above.

In this embodiment, the hook portion of the embodiment of figures 1 to 6 is omitted and the reservoir is removably secured to the spray gun 201 by cooperating bayonet formations on the connection tube 215 of the reservoir and the socket 221 of the spray gun 201.

As shown, the connector tube 215 is provided at its distal end with opposed outwardly extending projections 250 which form part of a bayonet connection. The adapter boss 220 of the spray gun 201 is formed internally with another part of the bayonet connection. More specifically, the inner wall of the socket 221 is formed with opposed inwardly facing grooves 251 extending axially from the outer free end of the boss 220 and terminating in an inner shoulder 233 within the circumferential groove 252.

In this manner, the reservoir is secured to the spray gun 201 by aligning the boss 250 with the axial groove 251 and pushing the connecting tube 215 into the socket 221 until the distal end of the tube 215 contacts the shoulder 233. The reservoir is then rotated so that the lugs 250 are within the circumferential grooves 252. In this manner, the reservoir is restrained by the bump 250. By reversing the operation, the reservoir can be detached from the spray gun 201.

In other respects, the tank is generally similar to the above embodiment and requires no further explanation, as it will be understood from the description thereof.

Referring first to fig. 11 and 12 of the drawings, yet another arrangement for removably securing a reservoir to a spray gun is shown. For convenience, like reference numerals in the series 300 are used to designate parts corresponding to the above embodiments.

In this embodiment, the spray gun 301 is provided with an outer joint boss 320 integral with the spray gun body 303. The connector boss 320 extends upwardly from the top of the body 303 and has an enlarged annular head 360 that forms a socket 321 formed to receive the open end of the disposable liner 309 and the outer container 308 for the liner 309.

The flange 312 of the liner 309 sits on the annular seat 361 within the receptacle 321 with an annular gap 362 between the sidewall 309b of the liner and the opposing sidewall 321b of the receptacle.

The side walls 321b of the socket 321 are smooth and taper slightly towards the base of the socket 321. The liner 309 is held in place by the push fit of the open end of the outer container 308 in the gap 362 for securing the flange 312 of the liner 309 between the seat 361 and the open end of the container. The frictional engagement for the tapered sidewall 321b of the receptacle 321 retains the receptacle 308 and ensures a fluid tight seal between the liner 309 and the receptacle 321.

Inside the seat 361, the base of the socket 321 is tapered and tapers towards a central bore to a bore 324 of smaller diameter relative to the socket, thereby providing an inlet for transferring paint from the reservoir 302 to the spray gun 301. In this way, paint flows towards the inlet, avoiding dead spaces where paint may become trapped.

The aperture 324 may contain a removable filter (not shown) for filtering paint as it is withdrawn from the reservoir to remove any solid particles. Alternatively or additionally, the paint may be filtered as it is being added to the reservoir.

In use, outer container 308 can stand on its base and liner 309 can be inserted within the open end to place flange 312 over the open end. Paint or other liquid to be sprayed may be added to and mixed in the liner 309.

The assembly of the liner 309 and container 308 may then be supplied to the socket 321 with the spray gun 301 in an inverted position such that the socket 321 faces downwardly, and the open end of the assembly pushed into the socket 321 for securing the outer container 308 and sealing the liner 309 relative to the socket 321.

The gun 301 may then be inverted to its normally upright position for spraying, with the liner 309 and container 308 held in place by frictional engagement of the container 308 within the socket 321. As the paint is drawn out, the liner 309 collapses and air enters the interior of the container 308 through air holes 308a in the bottom of the container 308.

Upon completion of the injection, the assembly of the liner 309 and container 308 can be detached from the spray gun 301 and the liner 309 discarded. A new liner 309 may be installed in the container 308 and the assembly reconnected to the spray gun 301 after cleaning the paint contaminated portion of the spray gun 301 for spraying another paint or liquid.

If any paint remains in the liner 309 after spraying, this remaining paint may be temporarily stored in the liner 309 by attaching a cap (not shown) to close the open end of the liner 309. The lid can be removed and the assembly of liner 309 and container 308 can be reattached to the spray gun 301 for application of the paint.

As will be appreciated, the connector boss 320 effectively forms the lid of the reservoir 302 by forming the connector boss 320 on the spray gun with the socket 321 for receiving the open end of the liner 309, and by securing the liner 309 by a push fit within the socket 321 using the outer container.

In this way, the number of parts is reduced, simplifying the assembly of the reservoir 302 and the connection to the spray gun 301. Also, after spraying, only the liner 309 must be discarded and replaced, providing a potential cost savings for the end user.

In a modification, as shown in figure 13, the outer container 308 is replaced by a tubular sleeve 370 which is open at both ends to allow different lengths of inner liner 309a, 309b, 309c, 309d to be secured with the same connecting sleeve 370. In this manner, by selecting and using the same adapter sleeve 370 to fit appropriately sized liners 309a, 309b, 309c, 309d, the volume of the tank 302 can be varied according to the area to be sprayed, thereby reducing the number of components required to fit a tank having a range of volumes.

The sleeve 370 may be used with the liner 309 contained wholly or partially within the sleeve 370. Thus, in fig. 13, the sleeve 370 is shown to be longer than each liner 309a, 309b, 309c, such that each liner 309a, 309b, 309c is protected and supported throughout its length by the sleeve 370. However, this is not an essential requirement and figure 13 also shows the sleeve 370 being shorter than the liner 309d, so that the liner 309d protrudes from the free end of the sleeve 370 and is protected and supported by the sleeve 370 over only a part of its length.

It will be appreciated that the socket 321 and receptacle 308 may be provided with any suitable threadless connector for releasably securing the reservoir 302 to the connector boss 320. For example, the receptacle 321 and the container 308 may be provided with cooperating bayonet formations or cooperating snap-engageable formations.

Also, it will be appreciated that the adapter boss 320 may be utilized to connect the tank to the spray gun 301 without the liner 309. For example, the outer container 308 may have a solid base provided with openable air holes to allow air to enter as paint is drawn out.

Referring now to figures 14 to 17 of the drawings, there is shown another arrangement for releasably securing the reservoir to the spray gun. For convenience, like reference numerals in the series 400 are used to designate parts corresponding to the above embodiments.

In this embodiment, the spray gun 401 is provided with an entire connector boss 420 in the form of a socket 421 and a separate removable insert 480 for receipt within the socket 421.

In some embodiments, insert 480 is a molded plastic piece that is releasably secured within socket 421 by a push fit and has an annular flange or collar 481 at the outer end that rests on the rim of socket 421. The insert 480 is constrained in place by friction.

However, it will be appreciated that any suitable threadless structure may be provided for releasably securing the insert 480. For example, the socket 421 and the insert 480 may be provided with cooperating bayonet structures or snap-engageable structures.

The insert 480 has a through bore 482 with internal threads 483 for engaging complementary external threads 484 at one end of a mating adapter 485. The adapter 485 has a through hole (not shown) and is provided at the other end with an outer flange 422 for cooperating with hook portions 416, 417 on the reservoir 402 to releasably secure the reservoir 402 to the spray gun 401.

The flange 422 and hook portions 416, 417 are similar to those shown in fig. 5 and 6, with this structure being able to connect and disconnect the reservoir 402 to the spray gun 401 as described above.

However, it will be appreciated that the reservoir 402 and the adapter 485 may be provided with any suitable complementary cooperating structure for releasably securing the reservoir 402 to the spray gun 401. Such as cooperating bayonet structures or snap-fit structures. Alternatively, the canister 402 and the adapter 485 may have cooperating threads.

As will be apparent, the insert 480 converts the socket 421 into receiving a threaded portion for mounting the reservoir 402. In this embodiment, the threaded portion is a separate adapter 485 to which the reservoir 402 is releasably secured. However, it will be appreciated that this is not an essential requirement and the threaded portion may be the outlet of the reservoir which may be screwed directly into the insert 480 without requiring the adapter 485.

The insert 480 is a separate component that can be removed from the socket 421 if a threaded connection is not required to connect the reservoir to the spray gun 401. In this manner, the receptacle 421 may be adapted for threadless connection of the reservoir by removing the insert from the receptacle 421, or for threaded connection of the reservoir by placing the insert 480 within the receptacle 421.

In this embodiment, the adapter 485 screws into an insert 480 within the socket 421. In this manner, the threaded engagement of the adapter 485 with the insert 480 may enhance the frictional engagement between the insert 480 and the socket 421. Thus, the reservoir may be secured in a fluid tight manner, reducing the risk of inadvertent separation of the reservoir 402 from the spray gun 401 when the spray gun is handled in use.

Referring now to figures 18 and 19 of the drawings, there is shown a modified arrangement of the arrangement of figures 11 and 12 for releasably securing the reservoir to the spray gun. For convenience, like reference numerals in the series 500 are used to designate corresponding parts.

In this embodiment, the enlarged annular head 560 of the joint boss 520 is provided with internal threads 590 and the outer container 508 of the tank 502 has complementary external threads 591. In this manner, outer container 508 may be threaded into head 560 for securing inner liner 509 in a fluid-tight manner relative to head 560.

The outer container 508 may be replaced with an open ended sleeve (not shown). For installing liners of different lengths, the volume of the tank 502 is changed as described above in connection with fig. 13. Alternatively, the inner and outer containers 508 may be omitted with an openable air inlet provided at the base. In this manner, liquid may be added directly to the container 508 for mounting on the spray gun 501.

As will be appreciated, the enlarged head 560 of the adapter boss 520 forms a cap for the open end of the reservoir 502, reducing the number of parts and facilitating the connection of the reservoir 502 to the spray gun 301 in a simple manner.

In a modification (not shown), the internal threads 590 on the head 560 may be replaced by external threads, and the outer container 508 may be replaced by an annular locking ring or collar having internal threads and a concentric inner sleeve or skirt. The inner sleeve separates from the internal threads and the collar is received in the gap between the head 560 and the liner 509 when threaded onto the head for securing and retaining the liner 509 within the socket 521.

In another modified embodiment (not shown) the inlet fitting 320, 520 with the enlarged head 360, 560 may be a separate component for releasable securement to the spray gun 301, 501, the invention including the structure of this attachment for mounting the reservoir to the spray gun.

Referring now to figures 20 to 52 of the drawings, various arrangements for securing the reservoir to the spray gun are shown. Other details of the structure and operation of the reservoir and lance are similar to the above embodiments and will not be described or illustrated. Like reference numerals in the series 600, 700, 800, 900, 1000 and 1100 are used to denote corresponding and similar parts to the above embodiments where appropriate.

Referring first to fig. 20, there is shown a non-threaded socket 621 in the body 603 of the gravity feed spray gun. The socket 621 has a cylindrical outer bore portion 621a and a cylindrical inner bore portion 621b connected by an inner annular shoulder 621 c. The diameter of the inner bore portion 621b is smaller than the diameter of the outer bore portion 621 a. At the bottom of the socket 621 is a sealing surface 621d, the purpose of which will be described later.

Spaced above socket 612 is a radial projection 686 integral with gun body 603. The projection 686 extends over a portion of the circumference of the receptacle 621 and is disposed rearward of the edge away from the outer aperture portion 621 a.

Referring now to fig. 21 to 24, there is shown a molded plastic insert 680, such as a nylon insert 680, for mounting within the socket 621 to convert the socket 621 to receive a threaded fitting (not shown) for connection to a paint reservoir. The threaded fitting may be an integral part of the reservoir or a separate part to which the reservoir is removably connected.

The insert 680 is a plastics moulding, for example a nylon moulding, and has a tubular body provided at one end with an external hexagonal flange 687 for engagement with a wrench or similar tool. Insert 680 has a cylindrical upper body portion 680a depending from flange 687 connected to a smaller diameter cylindrical lower body portion 680b by an outer annular shoulder 680 c.

The lower body portion 680b is sized to be an interference fit within the inner bore portion 621b to provide a fluid tight seal within the socket 621. The upper body portion 680a may be sized to provide an interference fit within the outer bore portion 621a, but more preferably is a tight fit to facilitate insertion of the insert 680 into the receptacle 621, as described below.

The upper body portion 680a is provided with trapezoidal cross-section upper and lower radial projections 680d, 680e extending about 180 degrees around the circumference of the upper body portion 680 a. As shown, the upper projection 680d is also helical, while the lower projection 680e is completely parallel to the shoulder 680 c. In this embodiment, the projections 680d have a pitch of about 3 millimeters, but it will be understood that this is not a fundamental requirement and that the pitch can be varied to suit any particular situation.

Insert 680 has a through bore 688 with an upper threaded portion 688a connected to a lower smaller diameter unthreaded portion 688b by an internal shoulder 688 c. Shoulder 688c provides an internal stop for limiting engagement of the threaded portion with upper threaded portion 688a to secure a paint reservoir.

In use, insert 680 is placed within socket 621 by first orienting the insert so that the gap 689 between the ends of projections 680d, 680e, extending about 180 degrees around the circumference of upper body portion 680a, aligns with radial projection 686 on spray gun body 603. The insert 680 may then be pushed into the receptacle 621 until the end of the upper projection 680d furthest from the ledge 687 is below the tab 686.

Insert 680 can then be rotated by engaging flange 687 with a wrench so that upper projection 680d contacts the underside of projection 686, as shown in fig. 25. The helical form of the upper projection 680d provides an inclined surface that cooperates with the projection 686 as the insert 680 rotates.

Accordingly, insert 680 is moved further into socket 621 until lower projection 680e contacts spray gun body 603 around the perimeter of socket 621. This requires less than a full rotation of the insert 680. The underside of the tab 686 may be helical with a similar pitch as the tab 680d to help axially move the insert 680 through contact of the tab 680d with the underside of the tab 686.

In this regard, an interference fit of lower body portion 680b within inner bore portion 621b is ensured for providing a fluid tight seal between spray gun body 603 and insert 680 within socket 621.

It also locks the insert 680 in place and prevents it from being axially withdrawn from the socket 621 until it is rotated in the reverse direction, realigning the tabs 686 with the circumferential gaps 689 between the ends of the tabs 680d, 680 e.

With the insert 680 in place and secured, the paint reservoir may be secured to the spray gun by a threaded connection to the threaded portion 688a of the insert 680. If desired, a wrench or other suitable tool may be used to grip the flange 687 to hold the insert 680 in place while the paint reservoir is attached to or detached from the spray gun. The threaded portion may be provided as an integral part of the reservoir or as a separate adapter to which the reservoir may be releasably connected.

As will be appreciated, the lower projection 680e provides a stop for limiting the movement of the insert 680 into the socket 621 and preventing damage caused by rotation beyond that required to secure the insert 680 and providing an effective seal in the socket 621. Also, when the fitting is screwed into hole 688a, insert 680 is prevented from rotating by the contact of projections 680a, 680e with projection 686 and spray gun body 603, respectively.

In the modified structure shown in fig. 51, an axial abutting portion 680h is provided at the upper end of the spiral-shaped projecting portion 680 d. The abutment portion 680h provides an end stop that cooperates with the tab 686 to limit rotation of the insert 680 relative to the tab 686 and to prevent over-tensioning when the insert 680 is secured within the receptacle 621.

In another modified arrangement (not shown), the tab 686 may extend further around the circumference of the socket 621 with the length of the tabs 680d, 680e on the insert 680 correspondingly shortened so that the tab 686 can pass through the gap between the ends of the tabs.

In another modified arrangement (not shown), the tab 680e may be positioned over the tab 680d such that the tab 686 is received between the tabs 680e, 680d, while the tab 680e again acts as a stop to limit axial movement of the insert 680 within the insert holder 621 by contact with the tab 686. Alternatively or additionally, the helical projection 680d may be provided with an end stop as described above to limit rotation of the insert 680 relative to the projection 686. Alternatively, the gap between the upper and lower surfaces of the projections 680d, 680e may be sufficiently reduced to limit rotation of the insert 680 relative to the projection 686.

Referring now to fig. 26-29, there is shown another plastic molded insert 780 that is generally similar to insert 680 described above.

As shown, the insert 780 has an annular flange 787 at one end and a helical projection 780d on the upper body portion 780a that cooperates with a radial projection 686 on the lance body 603 as described above. The lower projection 780e is omitted and the lower body portion 780b has an increased length and is not an interference fit but a tight fit within the inner bore portion 621b to facilitate insertion of the insert 780 into the receptacle 621.

In use, the insert 780 is inserted into the receptacle 621 by aligning the tabs 686 with the circumferential gap between the ends of the projections 780d, and rotating the insert to place the projections 780d under the tabs 686 on the gun body 603, as described above. The insert 780 can then be rotated by engaging the flange 787 with a suitable tool or while screwing the fitting about the paint reservoir (not shown) into the insert 780.

Upon rotation, the insert 780 is moved axially into the receptacle 621 by the projection 780d contacting the underside of the projection 686 until the sealing surface 780f at the inner end of the insert 780 contacts the sealing surface 621d at the bottom of the receptacle 621 (FIG. 20).

The sealing surface 780f may be provided by the insert itself, such as a flange integrally molded with the same or softer plastic insert 780, or by a seal, such as a rubber o-ring (not shown), located in an end wall of the insert. Likewise, sealing surface 621d may be provided by spray gun body 603 itself, such as an internal abutment shoulder, or by a seal, such as a nylon sealing ring or gasket, at the bottom of socket 621.

In a modified arrangement (fig. 52), an axial abutment portion 780h is provided at the upper end of the helical projection 780d, providing an end stop that cooperates with the projection 686 to limit rotation of the insert 780 relative to the projection 686 and to prevent over-tensioning of the insert 780. In another modification (not shown), the lower body portion 780b may be an interference fit within the inner bore portion 688b to provide a fluid tight seal without contacting the sealing surface 621d at the bottom of the receptacle 621.

In the above embodiment, the helical projections 680d, 780d have a pitch of 3 mm, with the cooperating surfaces on the projection 686 having a similar pitch. It will be appreciated that this is not an essential requirement and any suitable pitch may be used. Further, while the helical projections 680d, 780d and (where provided) the stop projection 680e extend about 180 degrees to leave a gap 689 of about 180 degrees in the circumferential direction for the projection 686 to pass through, it will be appreciated that this is not a fundamental requirement and the circumferential extent of the projections 680d, 680e, 780d may be varied as long as the resulting gap 689 is of sufficient size for the projection 686 to pass through.

Referring now to fig. 30 to 34, there is shown another plastic moulding 880 which can be used to convert socket 621 into a threaded fitting for engaging a paint reservoir.

As shown, the insert 880 has an annular flange 887 at one end that is provided with a notch 887a sized and shaped to receive a protrusion 686 on the spray gun body 603. The helical projections and stop projections are omitted from the upper body portion 880a and the lower body portion 880b is sized for an interference fit within the inner bore portion 621b to provide a fluid tight seal.

In use, insert 880 is positioned such that notch 887a is aligned with protrusion 686 on spray gun body 603. Insert 880 is then inserted axially into socket 621 until flange 887 seats about socket 621 on spray gun body 603 and tabs 686 are received in notches 887a, as shown in fig. 34. Then when the threaded portion for securing the reservoir is threaded into insert 880, insert 880 is prevented from rotating relative to spray gun body 603 by tabs 686 being engaged within notches 887 a.

As will be appreciated, unlike the above embodiments, the insert 880 is not axially constrained by engagement with the protrusion 686 and relies on the interference fit of the insert 880 within the socket 621 to seal and retain the insert 880 in a fluid tight manner. By forming insert 880 so that when a threaded fitting for securing the tank is screwed into place, upper body portion 880a will expand, the interference fit can be enhanced.

Referring now to fig. 35 to 39, there is shown another plastic molded insert 980 that can be used to convert the socket 621 for engagement with a threaded fitting for securing a paint reservoir.

The flange 987 is provided with a notch 987a and is also formed with opposing flat portions 987 b. The notch 987a is circumferentially larger than the protrusion 686. Thus, when inserted into the socket 621, the insert 980 is able to rotate to a limited extent, and the flat portion 987b allows the insert 980 to be held by a tool to prevent the insert 980 from rotating when a threaded fitting for securing the reservoir is screwed into the socket 980.

Again, the insert 980 is not axially constrained by engagement with the protrusion 686 and the insert 980 is sealed and retained in a fluid-tight manner by virtue of the interference fit of the insert 980 within the socket 621. The interference fit can be enhanced again by forming the insert 980 so that when the threaded portion for securing the tank is screwed into place, the upper body portion 980a will expand.

Referring now to fig. 40-44, a modified construction of the insert 980 is shown in which the lower body portion 980b is provided with a pair of axially spaced, annular sealing ribs 980d, 980 e. The ribs 980d, 980e are circumferentially continuous and provide a fluid tight seal with the inner bore portion 621b when the insert 980 is inserted into the socket 621.

It will be appreciated that the number and arrangement of the sealing ribs 980d, 980e may be different than shown, and any of the inserts 680, 780, 880, 980 described herein may be provided with one or more sealing ribs for sealing the insert within the socket 621.

As will now be apparent, each of the inserts 680, 780, 880, 980 described above converts the unthreaded socket 621 within the spray gun body 603 into a threaded fitting that receives a separate paint reservoir for securement. However, it will be appreciated that the outlet aperture of the reservoir may be adapted to each insert in a similar manner to allow the reservoir to be connected directly to the socket of the spray gun body.

The orifice and the reservoir may be formed separately and secured together, for example by welding, or they may be integrally formed, for example by moulding. Fig. 45 to 47 show a moulded plastic reservoir 1002 provided with an integral orifice 1015 at one end for connection to the socket 621 and a removable cap 1090 at the opposite end for applying liquid to the reservoir 1002. Cap 1090 is provided with an annular seal 1091 and a vent 1092 closed by a removable plug 1093.

As shown, orifice 1015 has a cylindrical portion 1080a provided with a helical projection 1080d for cooperating with a projection 686 on lance body 603. The cylindrical portion 1080a leads to an external threaded portion 1080g that is a clearance fit within the outer bore portion 621a of the socket 621, and in turn leads to a cylindrical portion 1080b that is received within the inner bore portion 621b of the socket 621

In a similar manner to insert 780 described above, reservoir 1002 is secured to spray gun body 603 by inserting aperture 1015 into socket 621 with tabs 686 aligned with gaps 1089 between the ends of helical projections 1080 d. The reservoir 1002 is then rotated so that the helical projection 1080d contacts the underside of the projection 686, causing the aperture 1015 to move into the socket 621 until the sealing surface 1080f at the inner end contacts and forms a fluid tight seal with the opposing sealing surface within the socket 621.

In a modified arrangement (not shown), the inner barrel portion 1080b is an interference fit within the inner bore portion 621b to similarly provide a fluid tight seal with the insert 680. Alternatively, the cylindrical portion 1080b may be provided with one or more sealing ribs for providing a fluid tight seal with the inner bore portion 621b similar to the insert 980.

The barrel portion 1080a, similar to the insert 680, may be provided with a second projection that provides a stop for limiting the extent of insertion of the aperture 1015 into the socket 621. Alternatively or additionally, an axial abutment can be provided at the upper end of the helical projection 1080d to provide an end stop for limiting rotation of the insert relative to the projection.

The threaded portion 1080g allows the reservoir 1002 to be connected to a spray gun having a threaded socket disposed within the spray gun body or within an adapter mounted on the spray gun body. It will be appreciated that threaded portion 1080g may be omitted.

In another arrangement, the reservoir may be provided with a separate removable part, such as a lid, and the aperture and lid may be formed separately and secured together, or they may be formed integrally. Fig. 48 to 50 show a moulded plastics cap 1110 for a reservoir (not shown) of the type described above with reference to fig. 1 to 6.

As shown, the cover 1110 is provided with an integral aperture 1115 for connection to the socket 621. The aperture 1115 is similar to the integral aperture 1015 of the reservoir 1002 described above, the structure and operation of which will be understood from the above description of the aperture 1015.

The above embodiments illustrate ways in which the present invention provides a quick connection for releasably securing a reservoir to a spray gun by avoiding the use of threaded, integral adapter means with the spray gun.

The quick-fit coupling also allows the reservoir to be releasably secured to the spray gun when containing paint by the push-twist action of the node, which requires less than a full rotation of the reservoir, thus reducing the risk of spillage.

It is to be understood that the exemplary embodiments described herein are intended to illustrate the wide variety of scope and applications of the invention. Features of the embodiments may be used alone or in combination with any other features of the same or different embodiments.

Further, while the exemplary embodiments described and illustrated are believed to represent the best structures presently known to the applicant, it will be understood that the invention is not limited thereto and that many modifications and improvements can be made within the spirit and scope of the invention as generally described herein.

For example, where the outlet orifice is adapted to be connected linearly to a socket, a valve system may be incorporated into the connection so that, when the orifice is connected, the means to open and close facilitates the flow of liquid from the reservoir to the spray gun. The means for closing may be opened in response to insertion and/or rotation of the outlet in the socket and closed by reversing the operation when the reservoir is removed.

Other structures for releasably securing the reservoir to the spray gun will be apparent to those skilled in the art. For example, the socket may be recessed within the gun body and adapted to receive a connecting tube of the reservoir. The reservoir and spray gun may be provided with any suitable inter-engageable structure for releasably securing the reservoir to the spray gun, without the use of multiple threads on the reservoir and spray gun.

It will also be appreciated that each insert can be adapted to convert the socket into a mounting of the reservoir using any other connection system for securing the reservoir to the insert. For example, the insert and reservoir may be provided with interengageable bayonet formations, as shown in figure 9. Alternatively, one of the insert and the reservoir may be provided with a flange and the other with at least one hook portion engageable with the flange, as shown in fig. 5 and 6. Alternatively, one of the insert and the reservoir may be provided with a flange and the other with at least one resilient leg portion arranged to engage the flange, allowing the reservoir to rotate relative to the socket in a fluid tight manner, as described in our co-pending uk patent application No. 0307902.7, filed 4/5/2003.

The reservoir may be any structure for containing paint to be delivered to the spray gun. For example, the reservoir may contain paint in the form of a sealed container that can be discarded after spraying, as described above. Alternatively, the reservoir may contain paint in the form of a reusable paint can which is cleaned after spraying.

The reservoir may be configured to allow paint to be added to the reservoir when connected to the spray gun. In this way, the reservoir can be refilled without removing the reservoir from the spray gun, allowing the spray area to require a larger paint volume than the reservoir can hold. Thus, the reservoir may be of compact size and shape to facilitate handling of the lance. In particular, by using a smaller volume refillable reservoir, the balance, stability and operability of the spray gun may be improved.

The reservoir may be refilled with paint to be sprayed. Alternatively, empty and filled reservoirs by the end user may be supplied. Pre-priming may be advantageous for spraying paints that do not require a specific formulation color, such as a standard color of primer, base coat, etc.

The present invention provides a spray gun and reservoir with integral cooperating structure that is engageable without threads. However, we can provide an adapter for converting an existing paint can to have a threaded adapter boss for use with a spray gun. This adapter may be screwed onto the adapter boss of the paint can, the adapter being provided with formations for engagement with a non-threaded formation on the spray gun body. In this manner, existing paint cans with threaded adapter bosses can be used with the spray gun of the present invention.

The lance may be of the gravity feed type as described herein. Alternatively, the lance may be of the suction-delivery type or of the pressure-delivery type. Pressure delivery types may use a gas line from a compressed air supply to the spray gun to assist in the transfer of paint from the reservoir to the spray gun. The invention is also applicable to other types and configurations of spray guns for spraying liquids as defined herein.

Other modifications and improvements will be apparent to those skilled in the art and are considered to be within the scope of the invention

Within the scope of the invention.

Claims (65)

1. A liquid spraying apparatus comprising a spray gun and a reservoir for the liquid to be sprayed, the reservoir having an outlet connectable to the spray gun to allow liquid to be drawn from the reservoir in use, the spray gun having integral connector means for threadless engagement with cooperating connector means on the reservoir by which means the reservoir is releasably secured to the spray gun.

2. The apparatus of claim 1, wherein: the spray gun has an integral socket adapted to connect to the reservoir outlet.

3. The apparatus of claim 2, wherein: the socket is provided with a through-hole to the inlet of the spray gun with which the outlet of the reservoir communicates when the reservoir is connected to the spray gun for delivery of liquid to the spray gun in use.

4. The apparatus of claim 2 or claim 3, wherein: the spray gun has a body with the socket recessed within the spray gun body.

5. The apparatus of claim 2 or claim 3, wherein: the spray gun has a body with a socket disposed within a fitting boss that projects from the spray gun body.

6. The apparatus of claim 5, wherein; the adapter boss is integrally formed with the spray gun body.

7. The apparatus of claim 5, wherein: the adapter boss is formed separately from the spray gun body and permanently secured to one another.

8. The apparatus according to any one of claims 2 to 7, characterized in that; the reservoir has an outlet that is open to a connecting tube integral with the reservoir that is received in the socket for connecting the reservoir to the spray gun.

9. The apparatus of claim 8, wherein: the reservoir and the spray gun are provided with engageable structure providing a push fit of the reservoir to the nozzle.

10. The apparatus of claim 9, wherein: the connecting tube and the socket are tapered such that the connecting tube is an interference friction fit in the socket for retaining the reservoir on the spray gun.

11. The apparatus of claim 8, wherein: the reservoir and the spray gun are provided with cooperable formations engageable by a push-twist action requiring less than a full rotation of the reservoir relative to the spray gun.

12. The apparatus of claim 11, wherein: the connecting tube and the socket are provided with bayonet-type structures engageable in the bore of the socket.

13. The apparatus of claim 11, wherein: the spray gun and reservoir are provided with engageable formations engageable externally of the bore of the socket.

14. The apparatus of claim 13, wherein: the engageable structure includes an integral, undercut retaining portion on the lance body.

15. The apparatus of claim 14, wherein: the reservoir is provided with external ribs on the connecting tube for cooperating with the underside of the retaining portion of the exterior of the socket for releasably securing the reservoir and preventing axial separation of the connecting tube from the socket.

16. The apparatus of claim 15, wherein: the rib has a spiral shape such that the connection tube is axially moved into the socket by the rib contacting the projection.

17. The apparatus of claim 16, wherein: a stop portion is provided to limit relative rotational and/or axial displacement of the connecting tube with respect to the socket.

18. The apparatus of claim 17, wherein; the stop portion includes an abutment portion at one end of the rib.

19. The apparatus of claim 17, wherein: the stop portion includes a further rib axially spaced from the helical rib.

20. The apparatus according to any one of claims 8 to 19, wherein: a fluid tight seal is provided by an interference fit of the connecting tube within the socket.

21. The apparatus according to any one of claims 8 to 20, wherein: the socket and/or the connection tube are provided with one or more sealing rings, such as o-rings, which are arranged to provide a fluid tight seal.

22. The apparatus of claim 16, wherein: by axial displacement of the connection tube, the end face of the connection tube is caused to contact an internal sealing surface within the socket, providing a fluid tight seal.

23. The apparatus of claim 14, wherein: an insert is provided for the receptacle for providing the receptacle with a matable structure that is compatible with a matable structure on the reservoir.

24. The apparatus of claim 23, wherein: the insert is provided with an external rib which is cooperable with the underside of the retaining portion external to the socket for releasably securing the insert and preventing axial separation of the insert from the socket.

25. The apparatus of claim 24, wherein: the rib has a helical shape such that the insert is axially displaced into the socket by contact of the rib with the projection.

26. The apparatus of claim 25, wherein: a stop portion is provided for limiting relative rotational and/or axial displacement of the insert relative to the receptacle.

27. The apparatus of claim 26, wherein: the stop portion includes an abutment portion at one end of the rib.

28. The apparatus of claim 26, wherein: the stop portion includes a further rib axially spaced from the helical rib.

29. The apparatus of claim 23, wherein: the insert is arranged to block the retention portion outside the socket.

30. The apparatus according to any one of claims 23 to 29, wherein: a fluid tight seal is provided by an interference fit of the insert within the socket.

31. The apparatus of any one of claims 23 to 30, wherein: the socket and/or the insert are provided with one or more sealing rings, such as o-rings, which are arranged to provide a fluid tight seal.

32. The apparatus of claim 25, wherein: the end face of the insert is caused to engage an internal sealing surface within the socket by axial displacement of the insert, providing a fluid tight seal.

33. The apparatus according to any one of claims 23 to 32, wherein: the insert is a nylon moulding.

34. The apparatus of any one of claims 23 to 33, wherein: a set of interchangeable inserts is provided to allow any selected attachment of an insert to provide any desired connector means to the socket.

35. The apparatus according to any one of claims 2 to 7, characterized in that: a sidewall of the reservoir forms an opening at one end of the reservoir, the opening forming an outlet, and an end of the sidewall is received in a socket of the spray gun for connecting the reservoir to the spray gun.

36. Apparatus according to claim 35 as appended to claim 5, wherein: the adapter boss of the spray gun is provided with an enlarged head which forms a socket and forms a lid for the reservoir.

37. The apparatus of claim 35, wherein; the socket has an annular seat engageable with an end of the sidewall surrounding the opening.

38. The apparatus of claim 37, wherein: the ends of the side walls are located and retained within the socket by an interference push fit within the socket to releasably secure the reservoir.

39. The apparatus of claim 37, wherein: the side wall and the socket are provided with complementary threadless connector means for releasably securing the reservoir.

40. The apparatus according to any of the preceding claims, characterized in that: the reservoir is reusable.

41. The apparatus of claim 40, wherein: the reservoir comprises a rigid tank which can be removed from the spray gun and cleaned when spraying is complete.

42. The apparatus of claim 41, wherein: the canister has an openable vent at an end remote from the connection to the spray gun to allow air to enter as liquid is drawn from the canister in use.

43. The apparatus of any one of claims 1 to 39, wherein: the reservoir is provided with a disposable container which can be discarded after use.

44. The apparatus of claim 43, wherein: the tank includes an outer container and an inner container collapsible and separable from the outer container as liquid is drawn from the tank so that the inner container can be removed and discarded after use.

45. The apparatus of claim 44, wherein: the outer container has a vent at an end remote from the connection to the spray gun to allow air to enter as liquid is drawn from the inner container in use.

46. A spray gun having a body provided with an integral socket for connecting a reservoir having a matable connector by push-fit or push-twist requiring less than one full rotation and an insert for converting the socket to connect a reservoir with a non-matable connector.

47. The spray gun of claim 46 wherein: the spray gun body and insert are provided with retaining portion formations which cooperate externally of the socket to prevent axial separation of the insert from the socket.

48. The spray gun of claim 47, wherein: one of the retaining portion formations includes a helical rib and the other retaining portion formation includes a projection cooperable with the rib to releasably secure the insert to the lance.

49. The spray gun of claim 48 wherein: the rib provides an inclined surface that moves the insert toward the lance in response to relative rotation securing the insert to the lance.

50. A spray gun as claimed in any one of claims 46 to 49, in which: the insert is configured to convert the socket into a screw connection to the reservoir.

51. A spray gun has an integral unthreaded fitting for mating engagement with an unthreaded fitting on a reservoir to releasably connect the reservoir to the spray gun.

52. The spray gun of claim 51, wherein: the threadless fittings on the spray gun and reservoir include a socket on one of the spray gun and reservoir adapted to receive a mating fitting on the other of the spray gun and reservoir.

53. The spray gun of claim 52 wherein: a socket is provided on the spray gun, the socket having an internal bore providing an inlet connectable to an outlet of the reservoir.

54. The spray gun of claim 53, wherein: the outlet of the reservoir is provided by a flow passage received in an aperture of a socket on the spray gun.

55. A spray gun as claimed in any one of claims 51 to 54, in which: a fitting is engageable within the bore of the socket for releasably connecting the reservoir to the spray gun.

56. A spray gun as claimed in any one of claims 51 to 54, in which: a fitting is engageable outside the bore of the socket for releasably connecting the reservoir to the spray gun.

57. The spray gun of claim 56 wherein: one of the fittings is provided with a helical rib and the other fitting is provided with a projection which cooperates with the rib for releasably securing the reservoir to the spray gun.

58. The spray gun of claim 57 wherein: the rib provides a ramp that moves the reservoir toward the gun in response to relative rotation securing the reservoir to the gun.

59. A spray gun as claimed in any one of claims 46 to 58, in which: including any of gravity feed, suction feed, or pressure feed lances.

60. A liquid spraying apparatus comprising a spray gun and a reservoir for spraying liquid, the reservoir being releasably connectable to the spray gun by a quick connect system which uses mateable connectors on the spray gun and the reservoir, wherein the spray gun has a body and the spray gun connector is integral with the spray gun body.

61. The apparatus of claim 60, wherein: when the reservoir is secured to the spray gun, the spray gun and reservoir form a connection axis.

62. The apparatus of claim 61, wherein: the engageable coupling is engaged/disengaged by relative axial movement substantially parallel to the axis of connection.

63. The apparatus of claim 61, wherein: the engageable coupling is engaged/disengaged by a combination of relative axial movement substantially parallel to the coupling axis and angular movement about the coupling axis.

64. A method of connecting a reservoir to a spray gun comprising providing a spray gun body with an integral unthreaded fitting, providing a reservoir with an unthreaded fitting mateable with the fitting of the body, and connecting the two fittings to releasably secure the reservoir to the spray gun.

65. The method of claim 64, wherein: the connectors are engageable for securing the reservoir to the spray gun with a push-twist action requiring less than one full rotation of the reservoir.