JP5773808B2 - Spray gun for paint - Google Patents

Description

  The present invention relates to a paint spray gun for atomizing paint with air and spraying the paint on an object to be coated.

  As a spray gun for paint used for spray coating (hereinafter sometimes simply referred to as spray gun), a hand gun type trigger spray gun that sprays paint while being atomized by pressurized air and adheres to the object to be coated. It has been known.

For example, in Patent Document 1, as shown in FIG. 8, an air flow path 101 through which pressurized air supplied from outside flows and a paint flow path 102 through which paint supplied from outside flows. A spray gun 100 that discharges paint from the tip of a nozzle 103 that is formed and communicated with the paint flow path 102 is disclosed. In the spray gun 100, pressurized air from the tip 104 of the air flow path 101 is supplied to the paint after being discharged from the nozzle hole at the tip of the nozzle 103 at the tip portion of the spray gun 100, and pressurized air is applied to the paint. Are mixed and the paint is atomized.
Moreover, the air flow path 101 branches in the middle, and the pattern adjustment flow path 105 for controlling the spray pattern of a coating material is formed.

  In the spray gun 100, since the air flow path 101 is formed in parallel and linearly with the paint flow path 102, air pressure loss and unevenness in the air flow path 101 are suppressed. It is said that poor atomization and jetting can be prevented and good coating can be performed.

  In such a form of spray gun, there is a problem that, when the supply pressure of pressurized air is high, scattering and rebound of the paint during coating increase. Therefore, what is called a low-pressure atomizing type spray gun is desired in which paint is atomized and sprayed well even with pressurized air having a low supply pressure.

JP 2006-192396 A

  However, in the spray gun described in Patent Document 1, when the supply pressure of the pressurized air is set to a low pressure, the atomization and injection of the paint become insufficient. If the atomization is insufficient, the paint that has not been atomized accumulates in the nozzle holes and becomes a large stagnation, which may fall on the object to be coated and cause an appearance defect.

  In particular, when a multicolored paint containing a columnar gel-like colorant having a length of 5.0 mm or more is used as the paint, the nozzle hole diameter is set so that the gel-like colorant is smoothly discharged. In the case of a spray gun provided with a nozzle having a large diameter, it is more difficult to atomize with pressurized air having a low supply pressure.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a low-pressure atomizing type spray gun in which paint is atomized and jetted well even by low-pressure pressurized air.

As a result of diligent study, the present inventor mixed paint and pressurized air inside rather than outside the spray gun, and after mixing, sprayed the object to be coated with low pressure pressurized air. However, it was conceived that the paint was atomized and sprayed well, and the present invention was completed.
The paint spray gun of the present invention is a trigger type paint spray gun that atomizes paint with air and injects it from an injection port, and the atomized pressurized air supplied from the outside circulates at the tip. An air flow path in which an air ejection hole is formed; a paint flow path through which paint supplied from the outside flows; a nozzle provided at a tip of the paint flow path and having a nozzle hole for discharging the paint; A spray gun body having a needle valve that reciprocates in the nozzle and opens and closes the nozzle hole, and a cap material having the injection port is attached to a tip of the spray gun body, the cap A mixing space in which the pressurized air ejected from the air ejection holes and the paint discharged from the nozzle holes are mixed is formed inside the material.
When the paint spray gun is not in operation, it is preferable that the tip valve portion of the needle valve protrudes outward from the outlet surface on the outer side of the injection port to close the injection port.
It is preferable that the cap member is provided with a regulating member that adjusts the spray pattern from the spray port of the paint.
The spray gun for paint according to the present invention is particularly preferably used when spraying various paints containing a gel-like colorant having a length of 5.0 mm or more.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the low pressure atomization type spray gun in which a coating material is atomized and injected favorably also with low pressure pressurized air.

It is a side view which shows the spray gun (at the time of non-operation) which is one embodiment of the present invention. It is a partial cross section side view of the spray gun (at the time of operation | movement) of FIG. (A) The expanded sectional view which expanded the principal part of FIG. 2, (b) The expanded sectional view which expanded the (a) further partially. It is the expanded sectional view to which the principal part of the spray gun (at the time of non-operation) of Drawing 1 was expanded. It is a side view which shows a mode that the cap material was removed in the spray gun of FIG. It is a front view of the spray gun of FIG. It is a front view of the spray gun main body which the spray gun of FIG. 1 comprises. It is a partial cross section side view which shows the conventional spray gun for coating materials.

The paint spray gun of the present invention will be described in detail below.
1 is a side view of a spray gun according to an embodiment of the present invention, FIG. 2 is a partial cross-sectional side view during operation of the spray gun of FIG. 1, and FIG. 3 is an enlarged cross-sectional view of an essential part of FIG. 4 is an enlarged cross-sectional view of the spray gun of FIG. 1 when not in operation, and FIG. 5 is a side view of the spray gun of FIG. 1 with a cap material removed.
6 is a front view of the spray gun of FIG. 1, and FIG. 7 is a front view of a spray gun body included in the spray gun of FIG.

  The spray gun 10 of this example includes a spray gun main body 20 extending in the horizontal direction, a cap member 30 detachably attached to the tip of the spray gun main body 20, and a hollow grip extending obliquely downward from the rear portion of the spray gun main body 20. And a trigger lever 50 pivotally supported by the spray gun body 20. The spray gun 10 is a trigger type in which a user grasps the grip portion 40 and operates a trigger lever 50 to inject the paint atomized by air from an injection port 31 opened in the cap material 30. Is. In addition, as shown in FIG. 3 etc., the internal side inlet surface of the injection port 31 formed in the cap material 30 is represented by the code | symbol 31b in a figure, and the external side exit surface is represented by the code | symbol 31a in the figure.

Inside the spray gun body 20 are formed a paint channel 21 through which paint circulates and an air channel 22 through which pressurized air for atomization circulates.
In the front part of the spray gun main body 20, a paint inlet 23 is formed which opens downward and is supplied with paint from a paint supply means such as a paint pressure feed tank, for example. The paint is supplied from 23.

  At the front end (downstream end) of the paint flow path 21, a nozzle 60 is provided that communicates with the paint flow path 21 and discharges the paint. The nozzle 60 is cylindrical, and a nozzle hole 61 is formed at the tip thereof. Further, in the nozzle 60, there is provided a round bar-like needle valve 70 capable of opening and closing the nozzle hole 61 by its tip valve portion 71 by reciprocating in the nozzle 60 in the axial direction. The needle valve 70 is connected to the trigger lever 50, and the opening / closing operation of the needle valve 70 is performed by operating the trigger lever 50. That is, when the operation of pulling the trigger lever 50 is not performed (when not operating), the needle valve 70 is urged forward to close the nozzle hole 61 and the discharge of the paint from the nozzle hole 61 is stopped. . On the other hand, when the trigger lever 50 is pulled (during operation), the needle valve 70 moves backward to open the nozzle hole 61, and the paint is discharged from the nozzle hole. 2 and 3 illustrate the operation, and FIG. 4 illustrates the non-operation. Further, it is desirable that the distal end portion of the needle valve 70, that is, the distal end valve portion 71 is tapered as in the illustrated example.

  An air inlet 24 to which pressurized air adjusted to a predetermined pressure is supplied from an air supply means such as a blower is formed at the lower end of the grip portion 40, and the air flow path 22 of the spray gun body 20 has this air flow path 22. Pressurized air supplied from the inlet 24 and passed through an air introduction channel (not shown) in the grip portion 40 is introduced.

  An air ejection hole 25 for ejecting pressurized air from the spray gun body 20 is formed at the tip (downstream end) of the air flow path 22. In addition, an air opening / closing valve (not shown) for opening and closing the connecting portion is disposed at a connection portion (not shown) between the air flow path 22 and the air introduction flow path. The air on / off valve is attached to the proximal end side of the needle valve 70, and the opening / closing thereof is interlocked with the opening / closing of the needle valve 70. That is, when the needle valve 70 is retracted and the nozzle hole 61 is opened by the operation of the trigger lever 50, the air on / off valve is also retracted to open the connecting portion, and the air introduction channel is changed to the air channel 22. Pressurized air is introduced to the air and pressurized air is ejected from the air ejection holes 25. On the other hand, when the needle valve 70 is urged forward and the nozzle hole 61 is closed, the air on / off valve is also urged forward to close the connecting portion and from the air introduction flow path to the air flow path 22. The inflow of the pressurized air is stopped, and the ejection of the pressurized air from the air ejection holes 25 is also stopped.

As shown in FIG. 7, a plurality of air ejection holes 25 formed at the tip of the air flow path 22 are formed, and are arranged in an annular shape so as to surround the nozzle hole 61 at the tip of the spray gun body 20.
In addition, as shown in FIG. 4, the needle valve 70 of this example has a tip valve portion 71 that extends from the outer outlet surface 31 a of the injection port 31 of the cap material 30 when the trigger lever is not pulled. It is located so as to protrude outward, and is configured to close not only the nozzle hole 61 but also the injection port 31 in front thereof.
Further, the diameter of the injection port 31 is larger than the diameter of the most distal end portion of the tip valve portion 71 and smaller than the maximum diameter of the needle valve 70.

The cap member 30 provided at the tip of the spray gun main body 20 includes a peripheral wall member 32 having a screw portion 34 screwed to the spray gun main body 20 formed on the inner periphery, and a header member 33 that closes one end of the peripheral wall member 32. And is detachably attached to the spray gun body 20. In addition, one injection port 31 is formed in the center of the header member 33.
When the cap member 30 is screwed to the tip of the spray gun body 20, a space is formed between the inside of the cap member 30 and the spray gun body 20, and this space is Prior to the injection of the coating material from the injection port 31, a mixed space S is formed in which the pressurized air ejected from the air ejection hole 25 and the coating material ejected from the nozzle hole 61 are mixed. The injection port 31 is preferably circular.

Further, as shown in FIG. 6, the cap member 30 of this example has a pair of blocks for adjusting the spray pattern by suppressing the spread of the paint sprayed from the spray ports 31 on the outer surface of the header member 33. A shaped regulating member 35 is formed. In the illustrated example, the restricting member 35 is arranged so as to be vertically arranged with the injection port 31 interposed therebetween. Therefore, the sprayed paint does not spread in the vertical direction and is formed in a horizontally long elliptical pattern.
Further, in this example, the peripheral wall member 32 and the header member 33 are formed separately, and when the cap member 30 is screwed, the header member 33 is rotated around the injection port 31 so that the regulating member 35 is arbitrarily set. The position (angle) can be adjusted and fixed. Therefore, the user can adjust the spray pattern of the paint not only to a horizontally long elliptical pattern but also to a vertically long elliptical pattern, an obliquely extending elliptical pattern, and the like.

Next, a method of painting using this spray gun 10 will be described.
First, an air supply means is connected to the air inlet 24 at the lower end of the grip portion 40. On the other hand, a paint supply means is connected to the paint inlet 23 of the spray gun body 20.
When the user is not operating the trigger lever when not operating, as shown in FIG. 4, the tip valve portion 71 of the needle valve 70 is positioned so as to protrude outward from the outer outlet surface 31 a of the injection port 31, The injection port 31 and the nozzle hole 61 are closed by a needle valve 70. Further, the connection portion between the air introduction flow path and the air flow path 22 is also closed by the air on / off valve.

Next, when the user operates the trigger lever 50 (during operation), as shown in FIG. 3, the needle valve 70 moves backward to open the nozzle hole 61 and the injection port 31, and at the same time, the air on / off valve is also opened.
As a result, the paint is discharged from the nozzle hole 61 and the pressurized air is jetted from the air ejection hole 25. In the mixing space S inside the cap member 30, the pressurized air ejected from the air ejection hole 25 and the paint ejected from the nozzle hole 61 are mixed.
Thus, the paint in which the pressurized air is mixed in the mixing space S is atomized while passing through the injection port 31, and is injected from the injection port 31 toward the object to be coated.

  In such a spray gun 10, a cap material 30 in which an injection port 31 is formed is attached to the tip of the spray gun body 20, and the pressurized air ejected from the air ejection hole 25 and the paint ejected from the nozzle hole 61. Is mixed in the mixing space S inside the cap member 30, then circulated through the injection port 31, atomized, and injected. Therefore, the pressurized air is mixed with the paint while maintaining the pressure, and as a result, the paint can be effectively atomized. Therefore, according to such a spray gun 10, even if the pressurized air is a low pressure of 0.03 to 0.2 MPa, for example, the paint can be atomized and sprayed well. When the atomization is performed well, the formation of lumps in the nozzle holes 61 is also suppressed, and the appearance defect due to the dams falling on the object to be coated is also reduced.

  On the other hand, in the form in which the paint and the pressurized air after being discharged from the nozzle hole are mixed outside the spray gun as in the conventional spray gun, the pressure of the pressurized air decreases during mixing. Therefore, when the supply pressure of pressurized air is low, it becomes difficult to atomize the paint effectively. As a result, the paint that has not been atomized becomes a large waste and may fall on the object to be coated, resulting in poor appearance.

In particular, if the paint is a multicolored paint containing at least a gel-like coloring material having a length of 5.0 mm or more, it is necessary to increase the nozzle hole diameter so that the gel-like coloring material is smoothly discharged. In that case, the conventional spray gun tended to make it difficult to atomize the paint better. In general, paints are particularly prone to forming lumps when the pressure of pressurized air for atomization is low. However, by providing the mixing space S inside the cap material 30, even when the nozzle holes 61 and the injection ports 31 are increased in diameter, the pressurized air and the paint are sufficiently mixed and good atomization can be performed. Even when the pressure of the pressurized air for atomization is low, generation of lumps can be suppressed. The length of the gel coloring material is usually 10.0 mm or less.
Examples of the gel coloring material include a spherical one and a cylindrical one. The length of the gel coloring material corresponds to the diameter in the case of a spherical shape, and corresponds to the length in the longitudinal direction in the case of a cylindrical shape. In addition, the length of the gel-like coloring material is a value measured by visual observation.

  Examples of the various paints include a paint composition containing a pattern formation group described in JP 2011-84700 A, JP 2011-52052 A, JP 2010-132747 A, JP 2009-173770 A. And a multicolor pattern coating composition described in JP-A-2007-70601.

  Further, when the spray gun 10 of this example is not in operation, as shown in FIG. 4, the tip valve portion 71 of the needle valve 70 protrudes outward from the outer outlet surface 31 a of the injection port 31, and only the nozzle hole 61 is provided. In addition, the injection port 31 is also completely closed. For this reason, it is possible to prevent the paint from being pushed out from the injection port 31 during non-operation so that the paint is accumulated in the injection port 31 and further the paint is dried and adhered. As a result, the painting operation can be continued for a long time without frequently cleaning the injection port 31, and the workability is extremely excellent.

  In the spray gun 10 described above, since the cap material 30 is detachably attached to the spray gun body 20, the cap material 30 can be removed and cleaned as necessary. The material may be formed integrally with the spray gun body, and is not necessarily removable.

  In the above example, a pair of restricting members 35 are provided on the outer surface of the header member 33 of the cap material 30 so that the injection pattern can be adjusted. Thus, you may provide the pattern adjustment flow path for adjusting a spray pattern in a spray gun main body. However, in the method of adjusting the spray pattern by providing the pattern adjustment flow path and blowing the air from this flow path to the paint, the paint is easily dried by the blown air, and as a result, the spray port is blocked. Easy to paint. When the injection port is blocked, it is necessary to clean the injection port, and the coating workability is lowered. In particular, when the pressurized air for atomization is set to a low pressure, the flow rate of the pressurized air may be increased in order to achieve good atomization. The coating workability tends to be further reduced. Therefore, it is preferable to adjust the injection pattern by forming the regulating member 35 as in the illustrated example, rather than adjusting the injection pattern by the action of pressurized air.

  There are no particular restrictions on the object to be painted by the spray gun 10, for example, ALC (lightweight cellular concrete), mortar coated surface, ceramic siding board, plaster, gypsum board, metal plate, concrete, wood, plastic, FRP Among them, among these, building materials for outer walls such as ALC, mortar-coated surfaces, ceramic siding boards are suitable.

DESCRIPTION OF SYMBOLS 10 Spray gun 20 Spray gun main body 21 Paint flow path 22 Air flow path 25 Air ejection hole 30 Cap material 31 Injecting port 31a Outlet side outside exit surface 31b Injecting port inside side entrance surface 35 Regulating member 60 Nozzle 61 Nozzle hole 70 Needle valve 71 Tip valve part S Mixing space

Claims (3)

It is a trigger type spray gun for paint that atomizes paint with air and sprays it from the injection port,
An air flow path in which pressurized air for atomization supplied from the outside flows and an air ejection hole is formed at the tip;
A paint flow path through which paint supplied from outside flows;
A nozzle provided at the tip of the paint flow path and having a nozzle hole for discharging the paint;
A spray gun body provided with a needle valve that reciprocates in the nozzle and opens and closes the nozzle hole;
A cap material in which the injection port is formed is attached to the tip of the spray gun body, and inside the cap material, pressurized air ejected from the air ejection hole and paint ejected from the nozzle hole, A mixing space is formed where
When the paint spray gun is not in operation, the tip valve portion of the needle valve protrudes from the outlet surface on the outer side of the injection port to close the injection port . The paint spray gun according to claim 1 , wherein a regulating member that adjusts a spray pattern from the spray port of the paint is formed on the cap material. The paint spray gun according to claim 1 or 2, wherein the paint is a multicolored paint containing a gel-like coloring material having a length of 5.0 mm or more.

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