JPS6380868A - Spray gun for paint - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spray gun, particularly for the application of liquid coatings such as paints and varnishes, for supplying liquid from a container to a spray nozzle via a container, a housing, and a spring-loaded outlet valve. It consists of a pump mechanism, a switch mechanism on the handle that causes the pump action, and a return duct that connects the outlet of the outlet valve to the container and has an additional adjustable valve inside.

Known spray guns typically have an electric piston or diaphragm pump, and the spray rate is typically adjusted by varying the piston stroke or diaphragm movement. For example, it is possible to reduce or limit the piston stroke mechanically to reduce the spray rate. If the liquid is to be applied very finely, and the piston stroke is significantly reduced, the atomization process will continue until uniform droplets are not formed or the liquid is applied unevenly. There is a risk that the pressure will drop. If the liquid is paint, the coating surface is uneven and large paint droplets are sprayed onto the coating surface in the form of a spray stream. This risk can be avoided by choosing a finer spray nozzle, but this also means limiting the spray angle.

In order to vary the size of the spray stream, a return duct for the displaced liquid is provided between the outlet port of the pump cylinder and the spray nozzle, in which a regulating valve is installed to open and close it to a maximum or minimum range depending on the pressure. is disclosed in German patent 912.560. This valve is regulated by a drive lever on the handle, which also drives the pump. The drive lever is moved to a predetermined abutment so that the return valve remains at a single, constant setting during application. On the other hand, if this lever does not reach the contact portion, the settings cannot be maintained and the spray flow cannot be kept constant. The abutment screw provided on the handle serves as a neutral position abutment point on the drive lever, but is not suitable for setting the spray flow during actual application. This is because the tightening of this abutment screw causes the electric switch to constantly react to even small movements of the drive lever.

Such a spray gun means that it cannot be switched off quickly.

It is therefore an object of the present invention to design a spray gun of the kind described above, which allows precise adjustment of the spray flow even when applying at very low spray rates.

To achieve other objects set out in the following specification and claims, a paint spray gun comprises a container, a housing having a handle connected to and being part of the container, a spray nozzle, and a spring loaded. a pump mechanism including an outlet valve for supplying liquid from the container to the nozzle; a switch in the handle for controlling the pump mechanism; and an additional adjustable internal valve extending from an arrangement of the valve to the container. The return duct provided with the switch comprises an adjustment member adapted to be disengaged from said switch and maintained in any 52 position, said adjustment member being provided at the front of the spray gun on the atomizing side.

The spray gun's spray flow, which is held by a handle and can be switched on and off, can be easily varied without interrupting the spraying process by using the user's hand to set the front adjustment member. .

Once the desired spray concentration has been set, the adjustment member is released and its set position remains constant whether the spray gun is switched on or off.

Short-term changes in the spray stream concentration are likewise effected by regular switching of the regulating elements.

The effects and improvements of the spray gun provided by the present invention are made clear in the claims.

In the present invention, the additional valve is completely closed by the adjustment member, which is superior to the previously described prior art in which the total spray pressure is adapted to the application, and even small substantial spray concentrations can be achieved, allowing adjustment of the adjustment settings. The degree of freedom increases significantly. In this regard, the additional valve has a spring loaded with the valve member, one end of which abuts the valve member, and the other end of which is coupled to the knob and located inside the adjustment member that is screwed to the additional valve. It is effective when it is elongated. This means that the spring-loaded valve closes firmly and easily without damaging or over-tightening the spring.

To simplify spray gun assembly, enhance existing spray guns with a return duct, and embody the invention, an additional valve can be slid or driven into the tubular outlet duct on the spray side. There is a need to.

The spray nozzle is screwed directly onto this outlet duct or valve, or by means of an intermediate member between the outlet duct and the valve. Advantageously, at least a part of the outlet duct is fitted within the housing and the other part is shaped to fit within the housing. The part of the outlet duct designed to be screwed on serves as an extension for receiving an additional valve for modifying the spray gun according to the invention.

With an effective design of the return mechanism, the outlet on the spray side has at least one radial boat, which corresponds to a radial inlet boat in an additional valve surrounding the outlet duct. There is also an axial outlet port on the valve that is offset with respect to the axis of the outlet duct 1~, which corresponds to the boat in the spray gun housing and is connected to the container. All connections are made automatically by sliding into the additional valve.

In order to precisely align these boats with one another, each of the corresponding unnecessary boats is provided with at least one annular duct. A seal is placed around the boat or annular duct. In order to improve the spray characteristics, by providing a back pressure space below the outlet valve, especially regarding the return duct,
It suppresses pressure fluctuations caused by pump operation and improves the uniformity of the spray flow when applying at low spray concentrations.

In this case, the effect of a large number of large droplets in the spray stream becomes virtually zero, and the spray stream is composed only of fine, medium-sized droplets. This has a good effect on the properties of the paint application. Preferably, the backpressure space is an area with a larger internal diameter within the outlet duct that accommodates the valve member and the valve spring of the outlet valve.

Two embodiments of the invention with slight differences will be explained in detail and by way of example in conjunction with the accompanying drawings, in which: FIG.

The rear part of the housing 10 is formed with a handle 1 for operating the spray gun, and includes an electric switch to turn on/off a pump (not shown) within the housing 10.

At the front of the housing 10, a container 13 for applying a liquid such as paint is arranged.

This container 13 is preferably made removable by screw means. A riser pipe 14 opened near the bottom of the container 13 has one end thereof opened so as to be connected to a pump cylinder 15. A pump piston 16 is arranged in the pump cylinder 15 so as to be reciprocatable. This piston 16 is normally connected to A (not shown).
It is driven by a C oscillating magnet system.

Details are given in the prior art cited above.

This AC magnet system is turned on and off by an electrical switch 12. Pump cylinder is valve boat 1
It opens at 7, and an outlet duct 18 is connected here. The outlet duct 18 adjacent to the valve port 1 17 has a larger inner diameter and acts as a backpressure space within which the moving valve is located, as will be explained in detail below in FIG.

The narrow portion of the connected alar duct 18 is open at the nozzle boat 20 of the spray nozzle 21. There is an additional valve 23 between the spray nozzle 21 and the connecting member 22 at the front top of the housing 10, which allows a connection between the narrow part of the outlet duct 18 and the container via an internal duct. The regulating member 24 is mounted in the additional valve 23 and has a rotating head 25 for its operation.

In the following specification, the structure and function of the additional valve 23 will be explained with reference to FIGS. 2 to 7.

FIG. 2 shows the front of the spray side of the housing 10 with the connecting member 22. FIG. Extending outwardly from the center of the connecting member 22 is a tubular connector 26 having external threads. This connector 26 forms part of the outlet duct 18 and has a back pressure space with a large inner diameter. This back pressure space 19 is heard at the valve boat 17 on the housing side. A boat or hole 27 is provided in the floor of the sleeve-like connecting member 22 on the housing side, leading to the interior of the container. It is also possible to provide several holes instead of one hole. Valve member 2
8 is pushed in the direction of the valve ports 1 to 17 by a spring 29, and one end of this member presses against an elastic member 30 that presses against a screwed stopper. port 2
7 and prior art spray gun without liquid return system (“640 Sl Elektronik”)
(7) sold by the assignee of this application), the stopper is connected to the tubular connector 26 as shown in FIG.
It takes the form of a spray nozzle 21 above.

The nozzle is made of plastic and has a metallic sleeve-like inner member 31 with a nozzle orifice 20 in the floor.
has. This elastic member 30 has a plurality of holes (not shown).

With the exception of port 27, which is of well-known design, the parts shown in FIGS. It is arranged between the connecting member 22 and the connecting member 22.

The plastic cylindrical intermediate member 33 shown in FIG. 3 is dimensioned to fit into the sleeve-like interior space of the connecting member 22. This member 33 has one or more axial holes 34 that are aligned with the ports 27. The intermediate member 33 is provided with a radial groove (not shown) or has a flat end face for engagement with a correspondingly formed counterpart in the coupling member 22 and positioned about the axis of this member 33. ing. It is obviously also possible to provide at least one annular groove in the opening of the ports 1 to 27 or 34, the radius of the groove being equal to the distance between the groove and the center axis of the respective part. In this case, even if the intermediate member 33 is twisted, no problem will occur.

A portion of the outlet duct 18 within the adapter 35 is screwed onto the tubular connector 26 so that the intermediate member 33 is fixed in place and sealed. The sleeve-shaped portion 36 of the adapter 35 is located around the tubular connector 26 and adjoins a cylindrical portion 37 having a small outer diameter. The internal space 38 of the cylindrical portion 37 also has a small outer diameter. When the adapter 35 is screwed, the elastic member 30 contacts the floor of the sleeve-shaped portion 36. The cylindrical part 37 with a small outer diameter has a peripheral groove 39 and is connected to the cylindrical internal space 38 through at least one hole.
is connected to. On both sides of the circumferential groove, annular seals 40 are provided as further circumferential grooves. Cylindrical internal space 3
The spray side end of 8 has a wide portion 41 adapted to receive yet another elastic member (not shown).

Adapter 35 serves to receive additional valve 23. The valve has a valve housing 42;
The internal space 43 is formed to match the outer shape of the adapter 35. The valve housing 42 is inserted into the adapter 35 and fixed in position by an intermediate member 44 (see FIG. 6) which is screwed onto the adapter 35. Intermediate member 44 has an internal thread that corresponds to the external thread of adapter 35, and also has a hexagonal nut head 45 for a spanner. The valve housing 42 has a radius equal to the distance of the bore 34 from the central axis and has an annular groove 46 facing toward the end surface of the housing 10 . Further internal space 4
3 is provided with a peripheral groove 47, which groove lies on the peripheral groove 39 of the adapter when the valve housing 42 is assembled.

An axial bore 48 extending from the annular groove 46 and a radial bore 49 extending from the peripheral groove 47 lead to the valve space 50 and pass through the outside of the valve housing 42 as an extension of the radial bore 49 having a large inner diameter. This valve space 50 has an Ill thread onto which the adjustment member 24 is screwed. The adjusting member 24 is designed in the form of a pole and has an axial blind hole 51 for a valve spring 52 which presses a valve member 53 against the opening of the radial bore 49 forming the valve seat. When the adjustment member 24 is screwed,
Thereby, the elastic force applied to the valve member 53 is
The end face of the adjusting member 24 increases significantly until it comes into contact with the valve member 53, so that the valve is completely closed. The valve spring 52 is therefore entirely within the blind hole.

Finally, the spray nozzle 21 is screwed onto the intermediate member 44, which has an external thread that corresponds to the external thread on the tubular connector 26.

Once valve 23 is fully closed, the spray gun is operated conventionally. In other words, the entire set spray pressure acts on the liquid and it is sprayed. When the coating concentration decreases, the adjusting member 24 is screwed out to the outside without interfering with the coating operation, so that a small amount of liquid flows into the holes 49 and 48, the annular groove 46, and the hole according to the injection pressure and adjustment of the adjusting member 24. 34
, and is pushed back into the container 13 through the hole 27.

The single back pressure space, which is larger than the space inside a typical spray gun, has a positive effect on coating performance because it plays the role of a buffer that suppresses the conventionally expected pressure fluctuations.

The liquid return always allows the liquid to flow back into the backpressure space 19, thus forcing it into the spray nozzle 21 which provides effective atomization even when applying through the spray nozzle at very low rates. Thus, pumping failures that occur in conventional spray guns due to intermittent operation of the pumping means, such as non-uniform ejection of liquid, especially during operation at low spray rates, are eliminated using the present invention.

By combining some of the illustrated parts, FIG.
Needless to say, it is possible to reduce the number of parts shown in FIGS. This is particularly desirable when the additional valve is opened as part of a commonly manufactured spray gun rather than as an improved component as in the present invention.

This valve 23 may be designed to be screwed on. Multiple annular ducts and seals may be added if desired.

The liquid return system of the present invention has application not only to spray guns equipped with electric piston pumps, but also to e.g.
It can be applied to spray guns with a diaphragm pump or to spray guns with pump means or containers that are independent of the spray gun itself. A pump mechanism as described below is also effective.

Known means of reducing the pump rate, such as devices for reducing the piston stroke according to the prior art mentioned above, are additionally used.

8 to 10 show another valve 6o configuration as a substitute for the additional valve 23 shown in FIG.

This valve 60 has a valve housing 61 similar to the valve housing 42 described above, and it is also possible to arrange the adapter 35 on the valve 60. Identical parts or functionally similar parts are given the same reference numerals as above, and their description will be omitted. The holding portion 62 is screwed into the internal thread of the valve space 50, and a valve adjustment member 63 is slidably inserted from inside. Valve spring 64 extends into a shaft blind hole 65 of adjustment member 63 and its other end supports a valve member 66. The inner end of the adjustment member 63 is provided with a joint surface 67, while the outer end is provided with a joint surface 67 that, when the joint surface 67 is in the stopped state,
It protrudes from the holding portion 62. At its outer end, the axial bore 48 extending out of the valve space 50 is provided with a connecting tube 68 which is inserted into an opening in the housing 10 and allows the paint or other liquid to be injected into the container. I am being guided by this.

Valve housing 61 has a flat 69 adjacent retainer 62 . The adjustment member 70 represented in FIG. 9 may be inserted into the valve housing 61 such that the part of the valve housing 61 with the flat 69 extends into a correspondingly formed internal space 71 within this member. . The interior surface 72 that engages the adjustment member 63 is wedge-shaped with a radius of curvature, so that twisting the adjustment member 70 will cause the member 63 to be inserted into the valve housing to a maximum or minimum extent.

The adjusting member 70 has an axial hole 73, receives the adapter 35, and is fixed in position parallel to the axis by the intermediate member 44 shown in FIG.

Although not shown for simplicity, the valve space 50
There is a seal for this purpose, or a seal that can be opened in other parts. Elastic rings or discs are also not shown, but if necessary, adjustment member 70 can be installed in a possible setting.
It may be provided between this member 70 and an intermediate member in order to hold it.

Instead of providing a sealing means for the adjustment member 63 with a sealing ring, the inner end of this member may be engaged with an elastic diaphragm, which would provide a sealing function and a spring action at the same time. This diaphragm serves as a mating surface for the valve member 66.

The spray nozzle takes the form of a metal interior 31 since the adjustment member 70 and the outlet side port 74 act as a sealing member surrounding the nozzle orifice 20 . By rotating the adjusting member 70, the adjusting member 63
can be positioned at a desired setting and a predetermined elastic force acts on the valve member 66. If the spray pressure exceeds this elastic force, the liquid or paint will open the valve and the shaft hole 4.
It flows backward through 8. This valve member 66 engages the adjustment member 63 so that its setting also provides a closing action of the valve.

FIG. 11 shows, as an alternative to the adapter 35 shown in FIG.
Another adapter 75 is shown. In this case, the internal space 38 with cylindrical walls has a large diameter so that the stretched spring 29 can extend out of it.

This spring extends between the valve member 28 and the deflection member 76 at the wide portion 41 . As a result, the mechanical design is simplified and the valve member 28 can, for example, be fitted with a spring and deflection member 7.
6 by removing the spray nozzle. This makes inspection and cleaning easier. If suitably designed, taking into account the dimensions and distances between the rotating parts, this spring 29 further improves the swirling and swirling properties of the flowing liquid. A tandem intermediate member (not shown) with spring 29 can also be provided to limit the length of the spring. This intermediate member is also designed to improve flow conditions.

In a further embodiment of the spray gun according to the invention shown in FIG. 12, an additional valve 77 is arranged in the housing 10. A backpressure space 19 is located within the housing 10;
On the other hand, on the outside of the housing there is only a regular spray nozzle 21 screwed on. The adjustment member 78 extends into the valve space 50 connected to the backpressure space 19 and reaches outside the housing with a rotary knob 79. This knob 79 is used to rotate the adjustment member 78 within the thread 80 to achieve the valve setting. As shown, the return duct 81 serves to connect the valve space 50 and the container 13.

It is clear that this adjustment member 78 can also be designed as described above in the invention, in particular it can be loaded with a spring and engage the seat with the spring.

It is also possible to design the adjustment member 78 to extend from the side of the housing 10 and provide the knob 79 on the side of the housing 10. Preferably, the rotary knob is in the form of a flat disc and knurled.

This adjustment member 78 may be, for example, a disc provided with a round hole or a tapering slot, such as is used to change the cross-section of a return duct.

Here, the term spray gun specifically refers to any spraying device that is applied to eject a liquid, such as liquid paint, under pressure from a nozzle. Such spraying instruments are typically different from guns as weapons and are therefore defined within the scope of automatic paint spraying systems.

[Brief explanation of the drawing]

Figure 1 is a side view of the spray gun with an additional valve and spray nozzle at the front, Figure 2 is an enlarged view of the front housing part of the spray gun where the outlet duct appears, Figure 3 is a diagram showing the connecting member, and Figure 4 is a view of the adapter. Figure 5 is a diagram showing a part of the outlet duct designed to take the shape of the valve. Figure 6 is a diagram showing the additional valve installed on the adapter.
7 shows a spray nozzle attached to the intermediate member; FIG. 8 shows an alternative design for an additional valve; FIG. 9 shows an adjustment member for the valve shown in FIG. 8. Figure 10 is a cross-sectional view of line knee 2 in Figure 9, Figure 11 is a diagram showing a mechanically different adapter design, Figure 12
2 represents a diagram showing another embodiment of a spray gun with an integrated additional valve; FIG. 10... Housing 13... Container 18.
・Outlet duct 21 ・Spray nozzle 24 ・Adjustment member 27 ・
··boat

Claims (23)

[Claims] (1) A pump mechanism that supplies liquid from the container to the nozzle, including a liquid container, a housing connected to the liquid container and having a handle that is part of the container, a spray nozzle, and an outlet valve that receives a spring force. a switch provided on the handle for controlling the pump mechanism; a return duct leading from the outlet of the valve to the container and having an adjustable additional valve inside; a paint spray gun, the paint spray gun comprising an adjustment member adapted to be maintained at the top of the spray gun on the atomizing side. (2) The paint spray gun according to claim (1), wherein the additional valve is completely closed by the adjusting member. (3) the additional valve has a valve member receiving a spring force, one end of the spring is directed to the valve member;
The paint spray gun according to claim 1 or 2, wherein the other end is supported by the adjustment member. (4) A paint spray gun according to claim (3), wherein the spring extends into an inner portion of the adjustment member. (5) Claim (2), wherein the adjustment member is arranged in a position adjustable manner on the thread of the valve and has a rotation knob;
The paint spray gun according to any one of (3) and (4). (6) Comprising a mechanism having a spring force and a second adjusting member having a wedge-shaped surface, the adjusting member is displaced with respect to the spring force mechanism, and the second adjusting member is located on the side remote from the valve member. A paint spray gun according to claim 3 or 4, which is configured to act on the end of the first adjusting member. (7) The paint according to claim (6), wherein the wedge-shaped surface is an inner surface of a second adjustment member, and the second adjustment member has a ring or cylinder shape and is rotatably attached to another valve. spray gun. (8) The paint spray gun according to any one of the above items of the claims, wherein the additional valve is attached to the housing of the spray gun. (9) The paint spray gun according to any one of the above items of the claims, wherein the additional valve is attached to a pipe-shaped outlet duct on the spray side by screwing or insertion. (10) The paint spray gun according to claim (9), wherein the spray nozzle can be screwed onto an outlet duct or valve directly or via an intermediate member. (11) The paint spray gun according to claim (10), wherein the insertion type additional valve can be positioned by an intermediate member that is screwed on. (12) The paint spray gun according to claim (11), wherein the adjusting member is rotatably fixed to the valve via an intermediate member, and the fixing force thereof is adjustable. (13) The spray side outlet duct has at least one radial port around the outlet duct aligned with the radial inlet of an additional valve, the additional valve being offset with respect to the axis of the outlet duct. 1
A coating material according to any one of claims 9 to 12, having a plurality of axial outlets aligned with a port in the housing, the port being coupled to the container. spray gun. (14) The paint spray gun according to claim (13), wherein the alignment port includes at least one ring-shaped groove. (15) The paint spray gun according to claim (13) or (14), wherein the port or ring-shaped groove is surrounded by a sealing member. (16) The paint spray gun according to any one of the preceding claims, wherein at least a part of the outlet duct is screwed to the housing. (17) The paint spray gun according to claim (16), wherein the valve member and the valve spring of the outlet valve are arranged in a portion having a larger inner diameter, specifically, in a connecting portion between the outlet portions. (18) The paint spray gun according to claim (13), wherein the valve spring is supported at one end by a valve member and at the other end by a spring member near the spray hole. (19) Claim (16) wherein an intermediate member is disposed between one end of the valve spring and the spring member.
) Paint spray gun described in item 1. (20) The paint spray gun according to any one of the above claims, which has a mechanism for regulating back pressure on the downstream side of the outlet valve. (21) A paint spray gun according to claim (19), wherein said portion having a large diameter and an internal chamber of the duct forms a back pressure chamber. (22) The paint spray gun according to claim (20), wherein the outlet duct has an inner diameter at the valve portion that is larger than an inner diameter necessary to accommodate the valve member and the valve spring. (23) The paint spray gun according to claim (8), wherein at least a portion of the outlet duct on the housing side is integrally connected to the housing.