GB2423035A

GB2423035A - Spray gun

Info

Publication number: GB2423035A
Application number: GB0602650A
Authority: GB
Inventors: Joao Jorge Bergner; Juergen Stoeger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2005-02-11
Filing date: 2006-02-09
Publication date: 2006-08-16
Anticipated expiration: 2026-02-09
Also published as: GB0602650D0; DE102005006359A1; CN1817479A; GB2423035B; CN1817479B

Abstract

A high volume low pressure spray gun comprises a body 17 having a bore passing therethrough, spray head 12 attached to one end and compressed air hose 20 attached to the other via elbow 11 (which may be equipped with a gripping member) extension tube 30. Bayonet fittings 21 and 31 are of a common design to allow hose 20 to connect directly to elbow 11. Container 23 holds spray medium 25 and communicates with the said bore via dip-tube 26. Either the spray head 12 or the container 23 may be pivotally mounted on the body 17, in a preferred embodiment the container is pivotally mounted via mounting 27 and may also be locked via button 28 at any appropriate angle. Triggers 33 and 48 operate a needle valve in the spray head via a common cable system 29, 43. The degree of travel of the triggers may be varied eg by an eccentric stop (not shown), which in turn limites the maximum amount by which the needle valve may be opened.

Description

V

Spray gun

Background art

The invention proceeds from a spray gun for operation on a compressed-air compressor according to the preamble of claim 1.

In known spray guns of this type, the housing is of a tubular design, carries the spray head at the one tube end and is fastenable at the other end by a bayonet catch to an air hose leading to the compressed-air compressor. The compressed-air compressor is, for example, an HVLP (highvolume low-pressure) compressor. The spray medium container of a fillable design is connected by a neck piece firmly to the housing and an ascending tube, which extends through the neck piece to a point close to the container base, opens out in the interior of the tubular housing in the air flow path between hose connection and spray head close to the spray nozzle integrated in the spray head.

With this spray gun the operator may work only in the immediate range delimited by the length of his arm, wherein he has to ensure a substantially horizontal alignment of the tubular housing and hence of the spray medium container because, if the spray gun is held in a position widely differing from the horizontal, spray medium may be sucked out of the container only when the spray medium container is completely full as, otherwise, the liquid spray medium drains from the mouth of the ascending tube directed towards the base. Successful spraying of surfaces that are horizontal or approximately horizontal or tilted at a small acute angle relative to the horizontal is basically impossible.

Advantages of the invention The spray gun according to the invention having the features of claim 1 has the advantage that, because the spray medium container is cradle-mounted relative to the housing, the spray medium container irrespective of the alignment of the housing always remains horizontally aligned and so, even given low spray medium quantities, the ascending tube always dips deeply enough into the liquid spray medium. Thus, whatever the alignment of the spray gun, an optimum application of spray medium onto the work surfaces is guaranteed. Work may continue until the spray medium container is completely empty.

Advantageous developments and improvements of the spray gun indicated in claim 1 are possible by virtue of the measures outlined in the further claims.

According to an advantageous embodiment of the invention, the spray head is rigidly connected to the housing and the spray medium container is held by means of a swivel joint on the housing. Given this structural design, the spray gun may be held in every possible angular position relative to the work surface and so it is also possible to spray, e.g. paint, horizontal and inclined surfaces such as ceilings, slopes, floors and the like.

According to an alternative embodiment of the invention, the spray medium container is held rigidly on the spray head and the spray head is connected by a swivel joint to the housing. In this embodiment of the invention, the spray gun may be used to spray surfaces difficult to access, where confined spatial conditions do not allow the spray gun to be held horizontally. The fact that the spray medium container hangs far down increases the stability of the articulated spray head.

According to an advantageous embodiment of the invention, on the rear end of the housing remote from the spray head connection means are provided for selectively attaching an extension tube, a handle or the air hose. These connection means allow the spray gun to be usable selectively for close-range work and for spraying surfaces situated beyond arm's reach of the operator. Extension tube and handle in turn carry connection means for connecting the air hose.

According to an advantageous embodiment of the invention, extension tube and handle each have an actuating lever for controlled opening of the spray nozzle, which actuating lever, when the extension tube or the handle is attached to the housing, provides access to the nozzle needle of the spray nozzle.

Drawings There now follows a detailed description of embodiments of the invention that are illustrated in the drawings. The drawings show: Fig. 1 a side view of a spray gun with extension tube, Fig. 2 a longitudinal section of the spray gun with extension tube of Fig. 1, Fig. 3 a side view of the spray gun with handle, Fig. 4 a side view of a modified spray gun with telescopic extension tube, Fig. 5 an enlarged view of the spray gun with telescopic extension tube of Fig. 4, Figs. 6 in a cutout style a side view of the spray gun and 7 with telescopic extension tube of Fig. 4 in two different operating positions, Fig. 8 a plan view of an eccentric sleeve disposed on the extension tube of the spray gun with extension tube of Fig. 2.

Description of the embodiments

The spray gun shown in side view in Fig. 1 and intended for operation on a compressed-air compressor, e.g. an HVLP (high-volume low-pressure) compressor, has a housing 11 that is closed off at its front end by a spray head 12. As may be seen from the sectional view of Fig. 2, integrated in the spray head 12 is a spray nozzle 13, which comprises a spray opening 14, a nozzle needle 15 controlling the spray opening 14, and a closing spring 16 that presses the nozzle needle 15 onto a seat surrounding the spray opening 14 at the spray head 12 and therefore closes the spray opening 14. By axial displacement of the nozzle needle 15 counter to the restoring force of the closing spring 16, the spray opening 14 is opened to a greater or lesser extent.

The housing 11 comprises a first tube stub 17, which carries the spray head 12, and a second tube stub 19, which is integrally connected to the first tube stub 17 by an elbow 18 and at the end carries connection means for the direct or indirect connection of an air hose 20 leading to the compressed-air compressor. In the embodiment, the connection means are a fastening part 211 of a bayonet catch 21. The housing 11 composed of tube stubs 17, 19 and elbow 18 encloses an air flow path 22, into which compressed air removed from the compressed-air compressor through the air hose 20 may be admitted from the end of the second tube stub 19 carrying the bayonet catch 21.

The spray gun further has a spray medium container 23, which comprises a neck piece 24 and a spray medium pot 25 fastened removably to the neck piece 24. The spray medium container 23 is held by means of the neck piece 24 on the housing 11, and an ascending tube 26 that passes through the neck piece 24 and extends to a point close to the base of the spray medium pot 25 opens out in the air flow path 22 close to the spray nozzle 13. To enable universal operation with the spray gun with variable alignment of the spray head 12, the neck piece 24 of the spray medium container 23 is held by means of a swivel joint 27 on the first tube stub 17 so that the spray medium container 23, given a different inclination of the first tube stub 17 of the housing 11 relative to its horizontal position shown in Figs. 1 and 2, always retains its horizontal position and the ascending tube 26 always dips into the liquid spray medium contained in the spray medium pot 25, even when the spray medium pot 25 contains only small residual quantities of spray medium.

For specific purposes, the cradle mounting of the spray medium container 23 that is realized by means of the swivel joint 27 may be locked by jamming the swivel joint 27 by means of a manually operable locking button 28.

For working with the spray gun at points far removed from the operator, there is attached to the spray gun illustrated in Figs. 1 and 2 an extension tube 30, which at its upper tube end carries the second fastening part 212 of the bayonet catch 21. By means of the bayonet catch 21 the extension tube 30 is rigidly connected to the housing 11.

A further bayonet catch 31 connects the end of the extension tube 30 remote from the spray gun to the air hose 20. In this case too, the one fastening part 311 of the bayonet catch 31 is fastened to the extension tube 30 and the other fastening part 312 to the end of the air hose 20.

The fastening parts 211 and 311 and 212 and 312 are of an identical design so that, when the extension tube 30 is removed, the air hose 20 may be connected directly to the housing 11 by means of the fastening parts 211 and 312. In such a situation the second tube stub 19 - in a manner not shown in detail here - is designed as a handle and provided with a suitable gripping element.

Disposed on the end of the extension tube 30 remote from the housing 11 is a gripping element 32 for holding the extension tube 30. Associated with the gripping element 32 is an actuating lever 33 for controlled opening of the spray nozzle 13. The actuating lever 33 is held pivotably on a holding part 34, which is connected to the gripping element 32 and engages around the outside of the extension tube 30. The actuating lever 33 in this case is designed as a one-armed angle lever, which at one end is supported pivotably at the swivel point 35. The other end portion of the angle lever extends at an acute angle over and at a distance from the gripping element 32 and forms a gripping part for the operator. Fastened at a distance from the swivel point 35 to the actuating lever 33 is a traction rope 29, which extends in the tube interior right up to the spray nozzle 13 and is connected to the nozzle needle 15.

When the actuating lever 33 is swivelled, the nozzle needle is lifted off the spray opening 14 counter to the action of the closing spring 16 and compressed air flows out of the spray nozzle 13, sucks a metered quantity of spray medium out of the spray medium container through the ascending tube 26 and sprays it through the spray nozzle 13.

For adjusting the opening stroke of the nozzle needle 15 an adjustable stop 36 interacting with the actuatiig lever 33 is provided, which limits the maximum possible angular travel of the actuating lever 33 and hence also the opening stroke of the nozzle needle 15. In the embodiment of Fig. 2, the stop 36 is realized by means of an eccentric sleeve 37 (Fig. 8), which is disposed rotatably on the gripping element 32. By rotating the eccentric sleeve 37, the radial distance of the gripping part of the actuating lever 33 from the eccentric sleeve 37 varies and so the angular travel of the actuating lever 33 is reduced to a greater or lesser extent.

For working at close range with the spray gun, instead of the extension tube 30 a handle 38, such as is shown in Fig. 3, may be attached to the housing 11. The handle 38 likewise carries at the one end a fastening part 212 and at the other end a fastening part 311, so that the handle 38 may be interlocked, on the one hand, with the housing 11 and, on the other hand, with the air hose 20. In the handle 38 an identical actuating mechanism to that in the extension tube 30 is provided for metered opening of the spray nozzle 13 and, when the handle 38 is attached to the housing 11, provides access to the nozzle needle 15. For this purpose, there may be disposed, for example, on the one hand on the tube end of the second tube stub 19 and on the hose-remote end of the handle 38 two coupling parts of a coupling, such as are described later with reference to Fig. 5, which establish a connection of the traction rope 29, which is fastened to the actuating lever 33, to a traction rope extending in the housing 11 and leading to the spray nozzle 13. Such a coupling may likewise be provided for exchangeable use of the extension tube 30.

The spray gun illustrated in Fig. 4 is modified compared to the previously described spray gun inasmuch as the ability of housing 11 and spray medium container 23 to swivel relative to one another is realized in that the spray medium container 23 is held rigidly on the spray head 14 and the spray head 14 is connected by a swivel joint 40 to the housing 11. The housing 11 is moreover connected to a telescopic extension tube 41. The telescopic extension tube 41, like the extension tube 30 described with reference to Figs. 1 and 2, is equipped with corresponding bayonet catches 21, 31, an actuating lever 33 and a gripping element 32, so that to this extent reference is

made to the previous description pertaining to the

extension tube 30. Identical components are therefore also provided with the same reference characters.

In order also to ensure use of the spray gun without the telescopic extension tube 41, the traction rope 29 for actuation of the nozzle needle 15 that is fastened by one end to the actuating lever 33 is fastened at the other rope end to a coupling part 421 of a coupling 42, which coupling part 421 is held in the end of the telescopic extension tube 41 facing the housing 11 so as to be axially displaceable to a limited extent. The coupling part 421 is loaded by a compression spring 49, which is supported at the tube side against a stop 50, in such a way that the traction rope 29 is taut. At the free end of the second tube stub 19 of the housing 11 the second coupling part 422 of the coupling 42 is likewise held so as to be axially displaceable to a limited extent. The second coupling part 422 is connected by a traction rope 43 to a coupling element 44 and is applied against a tube-side stop 50 by a compression spring 45, which is supported at the housing side and acts upon the coupling element 44. The coupling element 44 is connected by a pin 46 rigidly to the nozzle needle 15, which extends in an axially displaceable manner in a channel 47 formed in the spray head 12. The compression spring 45 acting via the pin 46 upon the nozzle needle 15 closes the spray opening 14 in the non- actuated state of the actuating lever 33. Acting on the coupling element 44 is a further actuating lever 48, which is pivotably supported on the first tube stub 17 of the housing 11. The further actuating lever 48, when pivoted in the direction of the second tube stub 19, displaces the coupling element 44, wherein the coupling element 44 via the pin 46 lifts the nozzle needle 15 off the spray opening 14. The second tube stub 19 is shaped like a handle and carries a suitable gripping surface, which is not shown here, so that the spray gun after removal of the telescopic extension tube 41 may be guided by hand and the operator may work at close range with the spray gun. When the telescopic extension tube 41 is attached, the coupling parts 421, 422 engage one into the other and the coupling 42 is closed. If the actuating lever 33 on the telescopic extension tube 41 is then actuated, then via the traction rope 29 the coupling 42 is displaced axially to a limited extent, so that in turn via the traction rope 43 and the pin 46 the spray nozzle 13 is opened.

As is evident from the sectional view of Fig. 5, the spray medium container 23 corresponds to the spray medium container 23 described with reference to Figs. 1 to 3, so that identical parts of the spray medium container 23 are provided with the same reference characters. The ascending tube 26 opens out in the widened end region of the channel 47, in which the nozzle needle 15 and the pin 46 extend.

Figs. 6 and 7 show various alignments of the telescopic extension tube 41, which is illustrated only in sections.

It is clear that, irrespective of the alignment of the telescopic extension tube 41, the spray head 12 with spray medium container 23 retains its horizontal alignment.

Spray medium may therefore be applied onto vertical, manually inaccessible surfaces from various positions of the operator.

Claims

S

Claims 1. Spray gun for operation on a compressed-air compressor having a housing (11), which is closed off at its front end by a spray head (12) containing a spray nozzle (13) and encloses an air flow path (22) leading from its rear end to the spray nozzle (13) and loadable with compressed air through an air hose (20) leading to the compressed-air compressor, having a spray medium container (23) situated in operating position below the air flow path (22), and having an ascending tube (26) that dips into the spray medium container (23) and opens out in the air flow path (22) close to the spray nozzle (13), characterized in that housing (11) and spray medium container (23) are designed to be pivotable relative to one another.
2. Spray gun according to claim 1, characterized in that the spray head (12) is rigidly connected to the housing (11) and the spray medium container (23) is held by means of a swivel joint (27) on the housing (11)
3. Spray gun according to claim 1, characterized in that the spray medium container (23) is held rigidly on the spray head (12) and the spray head (12) is connected by a swivel joint (40) to the housing (11)
4. Spray gun according to one of claims 1 - 3, characterized in that the swivel joint (27; 40) is manually lockable.
5. Spray gun according to one of claims 1 - 4, characterized in that on the rear end of the housing (11) remote from the spray head (12) connection means are provided for selectively attaching an extension tube (30) or a handle (38) or the air hose (20)
6. Spray gun according to claim 5, characterized in that extension tube (30) and handle (38) at their housing- remote end have connection means for the air hose (20)
7. Spray gun according to claim 5 or 6, characterized in that the connection means comprise at least one bayonet catch (21)
8. Spray gun according to one of claims 5 - 7, characterized in that an actuating lever (33) for controlled opening of the spray nozzle (13) is pivotably disposed on the extension tube (30) and is preferably disposed in front of and at a distance from a gripping element (32), which is disposed on the extension tube (30) close to the housing-remote tube end.
9. Spray gun according to claim 8, characterized in that disposed on the extension tube (30) is a stop (36) of a displaceable design, which limits the angular travel of the actuating lever (33)
10. Spray gun according to claim 8 or 9, characterized in that fastened to the actuating lever (33) is the one first end of a traction rope (29), the other second end of which is connectable to a nozzle needle (15) , which under spring action keeps the spray nozzle (13) closed.
11. Spray gun according to claim 10, characterized in that the second end of the traction rope (29) is fastened to a coupling part (421) of a coupling (42) comprising two coupling parts (421, 422) that are firmly connectable to one another, which coupling part (421) is disposed in the housing-side end of the extension tube (30) so as to be axially displaceable to a limited extent and is loaded by a compression spring (49), which is supported at the tube side, for tautening the traction rope (29)
12. Spray gun according to claim 11, characterized in that in the end of the housing (11) carrying the connection means the other coupling part (422) of the coupling (42) is disposed so as to be axially displaceable to a limited extent and that a traction rope (43) connected to the nozzle needle (15) is fastened to the second coupling part (43) and by virtue of a spring force acting upon the traction rope (43) pulls the coupling part (422) towards a housing-side stop (51)
13. Spray gun according to one of claims 1 - 12, characterized in that the extension tube (30) is designed as a telescopic extension tube (41)
14. Spray gun according to one of claims 1 - 13, characterized in that disposed on the housing (11) is an actuating lever (48) for controlled opening of the spray nozzle (13)
15. Spray gun according to claim 14, characterized in that coupling of the traction rope (43), which leads from the second coupling part (422) to the nozzle needle (15), is effected by means of a coupling element (44) that is firmly connected by a pin (46) to the nozzle needle (15), and that the actuating lever (48) acts on the coupling element (44) for dsp]acement thereof counter to the force of a compression spring (45), which applies the spring force to the traction rope (43)
16. Spray gun according to one of claims 1 - 15, characterized in that the housing (11) comprises a first tube stub (17) adjoining the spray head (12) , a second tube stub (19) carrying the connection means, and an elbow (18) that integrally connects the two tube stubs (17, 19) to one another.
17. Spray gun according to claim 16, characterized in that the actuating lever (48) disposed on the housing (11) is held pivotably on the first tube stub (17) and disposed in front of and at a distance from the second tube stub (19) designed as a handle.
18. A spray gun substantially as herein described with reference to the accompanying drawings.