JP2008012404A - Spray gun - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spray gun for easily changing the discharged amount of paint differently. <P>SOLUTION: A first piston 13, which is moved by both of the first piston air to be supplied through a first air supply passage 18 and the pressure of a second piston 15, and the second piston 15, which is positioned in the front of the first piston 13 and moved by the second piston air to be supplied through second air supply passages 21, 22, are arranged in a gun main body 1. The rear end of a needle valve 8 is screwed in the first piston 13. As a result, the moving amount of the needle valve 8 is easily changed by choosing between the first air supply passage 18 for moving the first piston 13 and the second air supply passages 21, 22 for moving the second piston 15 as a supply destination of compressed air and consequently the discharge is easily made in variable discharged amount of paint. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spray gun for painting.

For example, a spray gun as shown in Patent Document 1 is used for painting automobile parts and the like.
In this type of spray gun, the discharge of the paint from the discharge port is performed by moving the needle valve provided in the paint chamber in the front-rear direction.

A piston is disposed behind the paint chamber, and a rear end portion of the needle valve is fixed to the piston. The piston is urged forward by a spring. When piston air (compressed air) is supplied to the front of the piston, the piston moves backward against the biasing force of the spring. At this time, the needle valve also moves backward together with the piston, and as a result, the paint is discharged from the discharge port through a gap formed between the needle valve and the paint nozzle.
The rearward movement of the piston is regulated by the adjustment stopper. The adjustment stopper is configured to be able to change the position amount of the piston, and by adjusting the position of the adjustment stopper, the movement amount of the piston and the needle valve to the rear, that is, the discharge amount of the paint can be adjusted.

In this spray gun throw-off operation (washing of the paint chamber for changing the color of the paint, etc.), the cleaning liquid is supplied to the paint chamber and the paint remaining in the paint chamber is washed away with the cleaning liquid.
In this waste-blowing operation, if the gap between the needle valve and the paint nozzle is narrow, a sufficient amount of cleaning liquid cannot be supplied to the paint chamber and it takes time to throw away the waste. After a sufficient gap between the valve and the paint nozzle is secured, the waste blowing work is performed.
JP 2000-117157 A

However, if the position of the adjustment stopper is changed due to the waste-blowing operation, the position of the adjustment stopper has to be readjusted when painting again, and it takes time to start painting.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a spray gun capable of easily changing the amount of paint discharged from the discharge port.

  The spray gun of the present invention includes a gun body having a paint chamber, a paint discharge port provided at a front end of the paint chamber, a needle valve disposed in the paint chamber for opening and closing the discharge port, and the needle valve. An urging means for urging forward and closing the discharge port of the needle valve; and provided in the gun body, the needle valve is moved backward against the urging force of the urging means by supplying compressed air. A piston device that moves and opens the discharge port, the piston device being disposed in the piston chamber, a first piston having a rear end portion of the needle valve fixed thereto, A second piston disposed in front of the first piston in the piston chamber, and a front by supplying the compressed air between the first piston and the second piston in the piston chamber. A first air supply passage for moving the first piston backward; and supplying the compressed air to a front portion of the second piston in the piston chamber to move the first piston together with the second piston. A second air supply passage that moves backward, and when the compressed air is supplied from the first air supply passage, the first movement amount of the needle valve is from the second air supply passage. It is different from the second moving amount of the needle valve when compressed air is supplied.

  According to the present invention, the first piston is moved by the first piston air (compressed air) supplied from the first air supply passage, and the second piston is supplied from the second air supply passage. By providing a second piston that moves for air (compressed air) inside the gun body, the needle valve can be easily changed by simply switching the supply destination of the compressed air to the first air supply passage or the second air supply passage. You can change the amount of movement. Accordingly, it is possible to easily discharge with different discharge amounts.

Hereinafter, an embodiment in which the present invention is applied to an automatic air spray gun will be described with reference to FIGS. When it is necessary to indicate the direction, the direction in which the paint is discharged will be described as the front.
FIG. 1 shows an overall configuration of a gun body 1 of an air spray gun according to the present embodiment. The gun body 1 of the spray gun has a structure in which a body 3 is mounted on a base 2 having a rectangular block shape. Although not shown, the gun body 1 is used by being installed in a painting facility or attached to a robot arm via the base 2.

A cylindrical portion 3a is formed at the front end of the body 3, and a hole 3b is formed at the rear end. A cylindrical paint chamber 3c extending from the cylindrical portion 3a to the hole portion 3b is formed inside the body 3. A paint nozzle 4 is attached to the cylindrical portion 3a via a nozzle joint 5. The paint nozzle 4 has a discharge port 4a for discharging paint at the center of its front end. A cylindrical paint chamber 4b extending rearward is provided behind the discharge port 4a, and is configured to be continuous with the paint chamber 3c with an equivalent inner diameter. Further, on the outer peripheral side of the paint chamber 4 b of the paint nozzle 4, an atomizing air blowing passage 4 c that opens at the front end face of the paint nozzle 4 is provided.

  The air cap 6 is attached to the outer periphery of the paint nozzle 4 via a retainer 7. The air cap 6 is formed with a pattern air outlet passage 6 a that opens at the front surface of the air cap 6.

  The paint chamber 3c is configured to be supplied with a paint from a paint supply source (not shown) via a paint supply passage (A in FIG. 1 indicates a connection port of the paint supply passage). A needle valve 8 for controlling the flow rate of the paint is disposed so as to penetrate the paint chamber 3c. The needle valve 8 has a shape of an elongated round bar, and includes a needle shaft 8a that forms a shaft portion, and a tapered portion 8b. A male threaded portion 8c is formed at the rear end of the needle valve 8 (needle shaft 8a). When the needle valve 8 is displaced forward, the tapered portion 8b comes into contact with the discharge port 4a without any gap and closes the discharge port 4a. It is the structure which the coating material to discharge.

At the bottom of the hole 3b (the front end of the hole 3b in FIG. 1), a seal collar 9 is provided via a screw 10 in a state of being fitted on the outer periphery of the needle valve 8 (needle shaft 8a). It has been. The seal collar 9 prevents the paint supplied into the paint chamber 3c from leaking to the hole 3b side.
Moreover, the adjustment stopper 11 which makes a cover member is screwed by the hole 3b. The adjustment stopper 11 includes a cylindrical portion 11a located in the front half and a substantially columnar knob portion 11b located in the rear half. The rear opening of the hole 3 b is closed by the adjustment stopper 11, whereby a piston chamber 12 is formed between the hole 3 b and the adjustment stopper 11.

  A first piston 13 is screwed to the rear end portion of the needle valve 8 that protrudes into the piston chamber 12. The first piston 13 is configured to be movable in the front-rear direction along the inner peripheral portion of the cylindrical portion 11a, and moves backward until the rear end portion of the needle valve 8 contacts the inner bottom surface of the cylindrical portion 11a. Is possible. Accordingly, the inner bottom portion of the cylindrical portion 11 a of the adjustment stopper 11 functions as the first adjustment portion 14 of the first piston 13.

  A second piston 15 is disposed at the front of the first piston 13 and is inserted through the needle valve 8. The second piston 15 is slidable in the front-rear direction along the inner peripheral surface of the front portion of the piston chamber 12 and the outer peripheral surface of the needle valve 8 in the piston chamber 12. An annular convex portion 15 a is formed in the vicinity of the center of the rear end surface of the second piston 15 so as to surround the needle valve 8. The second piston 15 is configured to be movable rearward until the rear end surface 15b excluding the convex portion 15a contacts the front end surface of the cylindrical portion 11a. Accordingly, the front end surface of the cylindrical portion 11 a functions as the second adjustment portion 16.

  An L-shaped nipple (pipe joint) 17 is provided at the rear upper part of the body 3. One end of the nipple 17 is connected to a compressed air supply source (not shown), and the other end is connected to a first air supply passage 18 extending downward. The first air supply passage 18 communicates with a space 19 between the first piston 13 and the second piston 15 (a space on the outer periphery of the convex portion 15a). Accordingly, when the first piston air (compressed air) is supplied to the nipple 17, the first piston air is supplied to the space 19 through the first air supply passage 18. As a result, the first piston 13 moves rearward, and the needle valve 8 moves rearward along with this. Thereby, the discharge port 4a is opened.

  At the bottom of the base 2, an nipple 20 having an L shape is provided. One end of the nipple 20 is connected to a compressed air supply source (not shown), and the other end is connected to a second air supply passage 21 extending upward. The second air supply passage 21 communicates with the space 23 between the front end of the second piston 15 and the piston chamber 12 via the air supply passage 22 (see FIG. 2). Accordingly, when the second piston air (compressed air) is supplied to the nipple 20, the second piston air is supplied to the space 23 through the second air supply passages 21 and 22. As a result, the second piston 15 moves rearward, and the convex portion 15a provided on the second piston 15 presses the first piston 13 rearward. As a result, the needle valve 8 moves rearward together with the first piston 13, and the discharge port 4a is opened.

A spring 24 is disposed between the first piston 13 and the first adjustment unit 14. The spring 24 always urges the first piston 13 forward. When the first piston 13 is biased forward, the needle valve 8 and the second piston 15 are also biased forward.
Thus, the adjustment stopper 11, the piston chamber 12, the first piston 13, the second piston 15, the first air supply passage 18, the second air supply passages 21 and 22, and the spring 24. Thus, the piston device 25 is constituted.

  When the knob portion 11b is rotated clockwise or counterclockwise, the adjustment stopper 11 is configured to be screwed back and forth. Thereby, the adjustment parts 14 and 16 of the adjustment stopper 11 also move, and the movable range of the first and second pistons 13 and 15 changes. That is, the opening degree of the discharge port 4a is changed by the operation of the knob portion 11b, and the discharge amount can be changed.

  A nipple 26 for supplying atomizing air is provided on the rear surface of the base 2 so as to protrude rearward. Although not shown, the nipple 26 has one end connected to a compressed air supply source and the other end communicating with the atomizing air blowing passage 4c. Thus, when atomizing air (compressed air) is supplied to the nipple 26, the atomizing air is blown out from the front end of the coating material nozzle 4, and the coating material discharged from the discharge port 4a is atomized.

  Although not shown, a nipple for supplying pattern air is provided in the vicinity of the nipple 26 (on the front side of the drawing with respect to the nipple 26 in FIG. 1). One end of the nipple is connected to a compressed air supply source, and the other end communicates with the pattern air outlet passage 6a. Thus, when pattern air (compressed air) is supplied to the nipple, the pattern air is blown out from the front end of the air cap 6, and the mist-like paint is formed into a predetermined pattern (shape and size such as a round shape and a fan shape). Change. The pattern can be selected by exchanging the paint nozzle 4 and the air cap 6.

Next, the operation of the above configuration will be described.
When the paint of the gun body 1 configured as described above is not discharged, the supply of air for the first and second pistons is stopped, and the first and second pistons 13 and 15 are not moved. Therefore, as shown in FIG. 1, the first piston 13 is biased forward by the spring force of the spring 24. As a result, the needle valve 8 screwed to the first piston 13 and the second piston 15 pressed by the first piston 13 are also urged forward. By the urging of the needle valve 8 forward, the tapered portion 8b is in contact with the paint nozzle 4 and closes the discharge port 4a. Further, the supply of paint, pattern air, and atomizing air is also stopped. Here, the knob portion 11b of the adjustment stopper 11 is rotated in advance, and the first and second adjustment portions 14 and 16 are moved by a predetermined amount to adjust the displacement position (paint discharge amount) of the needle valve 8. Keep going.
In addition, each position of the 1st and 2nd pistons 13 and 15 at the time of non-ejection will be described as an initial position.

  At the time of painting, the second piston air is supplied to the space 23, and the paint is supplied from the paint supply passage to the paint chambers 3c and 4b. The supply of the second piston air moves the second piston 15 backward. And the 1st piston 13 pressed by the convex part 15a of the 2nd piston 15 moves back against the urging | biasing force of the spring 24, as shown in FIG. Thereby, the needle valve 8 screwed to the first piston 13 also moves backward. As a result, the tapered portion 8b is separated from the paint nozzle 4, the discharge port 4a is opened, and the paint is discharged from the discharge port 4a. Note that the rearward movement amount of the needle valve 8 is a distance from the initial position of the second piston 15 to the rear end surface 15b of the second piston 15 abutting against the second adjusting portion 16.

  Simultaneously with the discharge of the paint, pattern air and atomizing air are also supplied. Then, the atomizing air is ejected through the atomizing air blowing passage 4c, and the pattern air is ejected through the pattern air blowing passage 6a. Accordingly, the paint is ejected from the paint nozzle 4 in a predetermined pattern, and the object to be coated is applied.

  When the color of the paint is changed, the paint chamber is cleaned (discarding operation) with a cleaning liquid. At the time of this discarding operation, the connection destination of the paint supply passage is switched from the paint supply source to a cleaning liquid supply source (not shown), and the cleaning liquid is supplied to the paint chambers 3c and 4b through the paint supply passage. Simultaneously with the supply of the cleaning liquid, the first piston air is supplied to the space 19. At this time, the second piston 15 is stopped at the initial position.

  On the other hand, as shown in FIG. 3, the first piston 13 and the needle valve 8 move backward until the rear end of the needle valve 8 abuts against the first adjusting portion 14 against the urging force of the spring 24. To do. As a result, the tapered portion 8b is separated from the paint nozzle 4, the discharge port 4a is sufficiently opened, and a large amount of cleaning liquid is discharged from the discharge port 4a. Thus, the paint remaining in the paint chambers 3c and 4b is washed away by the cleaning liquid in a short time. At this time, the supply of pattern air and atomizing air is stopped. The moving amount of the needle valve 8 at the time of the waste blowing operation is a distance from the position of the needle valve 8 at the time of non-ejection until the rear end of the needle valve 8 comes into contact with the first adjustment unit 14.

  When the waste blowing operation is completed, the supply of the first piston air is stopped. Then, the first piston 13 is urged forward again by the spring force of the spring 24, moves forward together with the needle valve 8, and stops at the initial position. Thereby, the taper-shaped part 8b contacts the paint nozzle 4 and closes the discharge port 4a. Then, the connection destination of the paint supply passage is switched again from the cleaning liquid supply source to the paint supply source. On the other hand, the supply of paint, pattern air, and atomization air remains stopped.

  According to the present embodiment, the piston device 25 that moves the needle valve 8 that opens and closes the discharge port 4a back and forth is configured by arranging the first and second pistons 13 and 15 in one piston chamber 12. . Further, when the first piston air is supplied to the piston chamber 12, the first piston 13 moves rearward, and when the second piston air is supplied, the first piston 13 is pressed by the second piston 15 to be first. The piston 13 is configured to move backward. The amount of movement of the first piston 13 when the first piston air is supplied differs from the amount of movement of the first piston 13 when the second piston air is supplied. For this reason, it is possible to change the opening degree of the discharge port 4a by changing the moving amount of the needle valve 8 only by switching the supply passage of the compressed air to the piston chamber 12. Therefore, unlike the conventional spray gun that cannot change the discharge amount without moving the adjustment stopper, the discharge amount can be easily changed.

Further, the piston chamber 12 was constituted by a hole 3 b provided at the rear end of the gun body 1 and an adjustment stopper 11 having the first and second adjustment parts 14 and 16 which closed the hole 3 b. That is, the lid member itself that closes the hole 3 b was used as the adjustment stopper 11. Therefore, the number of parts can be reduced as compared with the configuration in which the lid member and the adjustment stopper are separately provided, and the configuration of the piston device 25 can be simplified.
Further, the adjustment stopper 11 is configured to be movable. For this reason, the position of the 1st and 2nd adjustment parts 14 and 16 can be adjusted only by adjusting the position of the adjustment stopper 11. FIG.

The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
Although the cleaning liquid is used for discharge by the first piston 13 in the above embodiment, a paint may be used instead of the cleaning liquid. This paint may be the same color as the second piston 15 or a different color. In the case of the same color, discharge can be performed with a discharge amount different from the discharge amount by the second piston 15 without changing the adjustment of the adjustment stopper 11. In the case of different colors, it is not necessary to change the adjustment of the adjustment stopper 11, so that the time for color change can be shortened.

  In the above embodiment, the movement amount of the first and second pistons 13 and 15 is changed by moving the adjustment stopper 11, but the first and second adjustment units 14 and 16 are replaced by replacing the adjustment stoppers with different shapes. The position may be changed. That is, the movement amount of the first piston 13 is a distance from the position of the needle valve 8 at the time of non-ejection until the rear end of the needle valve 8 comes into contact with the first adjustment unit 14. Therefore, the movement amount of the first piston can be changed by replacing the adjustment stopper 11 with an adjustment stopper having a different depth of the depression (depth of the cylindrical portion).

  The amount of movement of the second piston 15 is the distance from the position of the needle valve 8 at the time of non-ejection until the outer peripheral portion of the rear end portion of the second piston 15 comes into contact with the second adjustment unit 16. Therefore, the movement of the second piston 15 can be achieved by replacing the adjustment stopper 11 with an adjustment stopper having a different position of the front end surface of the cylindrical portion (the length from the rear end surface of the adjustment stopper to the front end surface of the cylindrical portion). The amount can be changed.

  In the above embodiment, the lid member is configured from the adjustment stopper 11 in which the first adjustment portion 14 and the second adjustment portion 16 are integrated. However, the adjustment stopper having the first adjustment portion, You may comprise a cover member from the adjustment stopper which has an adjustment part. In this case, a knob portion for positioning the first adjustment portion and a second adjustment portion are positioned on the other end surface side of each adjustment stopper (a surface opposite to the first and second adjustment portions). Each knob portion is provided. With this configuration, the movement amount of the first piston 13 and the movement amount of the second piston 15 can be set independently.

In the above-described embodiment, the adjustment stopper is detachably attached to the gun body and is movably attached. However, the adjustment stopper may be fixed to the gun body so as not to be detachable or detachable. However, it may be configured to be immovable.
Further, the adjustment stopper 11 may be changed to a lid member having no adjustment function. In this case, the lid member is configured to only block the hole. And the 1st and 2nd adjustment part which controls the movement to the back of the 1st and 2nd pistons 13 and 15 is good to provide in the inner peripheral surface etc. of a hole, for example separately from a lid member.

  In the above embodiment, the spring 24 is positioned behind the first piston 13. However, any position, for example, ahead of the first piston 13, can be used as long as the needle valve 8 can be biased forward. You may provide in the position. Further, although the spring 24 is provided as the urging means, an elastic member such as rubber may be used.

Overall sectional view showing an embodiment of the present invention Enlarged sectional view of the piston device when the second piston air is supplied Enlarged sectional view of the piston device when the first piston air is supplied

Explanation of symbols

  In the drawings, 1 is a gun body, 3b is a hole, 3c and 4b are paint chambers, 4a is a discharge port, 8 is a needle valve, 11 is an adjustment stopper (lid member), 12 is a piston chamber, and 13 is a first piston. , 14 is a first adjusting portion, 15 is a second piston, 16 is a second adjusting portion, 18 is a first air supply passage, 21 and 22 are second air supply passages, and 24 is a spring (biasing force). Means), 25 indicates a piston device.

Claims (3)

A gun body having a paint chamber;
A paint discharge port provided at the front end of the paint chamber;
A needle valve disposed in the paint chamber for opening and closing the discharge port;
Urging means for urging the needle valve forward to cause the needle valve to close the discharge port;
A piston device that is provided in the gun body and moves the needle valve rearward against the urging force of the urging means by supplying compressed air to open the discharge port;
The piston device includes a piston chamber,
A first piston disposed in the piston chamber and having a rear end fixed to the needle valve;
A second piston disposed in front of the first piston in the piston chamber;
A first air supply passage for moving the first piston backward by supplying the compressed air between the first piston and the second piston in the piston chamber;
A second air supply passage that moves the first piston rearward together with the second piston by supplying the compressed air to the front portion of the second piston in the piston chamber;
The first movement amount of the needle valve when compressed air is supplied from the first air supply passage is the second movement amount of the needle valve when compressed air is supplied from the second air supply passage. A spray gun characterized by different travel. The piston chamber has a hole provided at the rear end of the gun body,
A lid member detachably attached to the gun body so as to close the hole,
The lid member includes a first adjustment portion that restricts the backward movement of the first piston, and a second adjustment portion that restricts the backward movement of the second piston. The spray gun according to claim 1. The piston chamber has a hole provided at the rear end of the gun body,
A lid member detachably attached to the gun body so as to close the hole,
The lid member includes a first adjustment unit that restricts rearward movement of the first piston and a second adjustment unit that restricts rearward movement of the second piston, and the first and first 2. The spray gun according to claim 1, wherein the position of the two adjustment units can be changed.

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