JP2003038987A - Coating gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a liquid sprayed on the outside surface of a gun body from entering into a void part of the gun body. SOLUTION: The gun body 10 is constructed by assembling a plurality of parts and the void part 23 is secured inside. A communicating hole 36 for making an air flow passage 31 and the void part to communicate with each other is formed on a wall part 27W constituting the air flow passage 31 provided in the void part 23. Even when the liquid sprayed on the outside surface of the gun body 10 enters into the void from the clearance among the parts constituting the gun body, the entering of the liquid is surely obstructed with the air pressure in the void part 23 by supplying high pressure air into the void part 23 through the communicating hole 36 from the air flow passage 31.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating gun.

[0002]

2. Description of the Related Art Conventionally, as a coating gun, a high voltage generator is housed inside the gun body, a paint flow path and an air flow path are provided, and the paint supplied to the gun body is electrostatically charged by the high voltage generator. There is a device in which air is ejected from a nozzle in an applied state and air is ejected from the nozzle for atomizing paint and adjusting a coating pattern. The gun body is
The inside is hollow for the purpose of weight reduction, and the gun body is formed by assembling a plurality of parts to form the hollow portion.

[0003]

The coating gun is regularly cleaned because paint adheres to the outer surface of the gun body and stains it. When cleaning, a solvent such as thinner is sprayed on the outer surface of the gun body by air spray. It is sprayed at high pressure with a gun. Therefore, the sprayed solvent infiltrates into the cavity of the gun body through the gap between the multiple parts that make up the gun body, and the invaded solvent adheres to the high voltage generator and deteriorates it. The infiltrated paint may infiltrate into the paint flow passage or the air flow passage and solidify to cause a coating failure.

The present invention was devised in view of the above circumstances, and an object thereof is to prevent a liquid such as a cleaning solvent from entering the cavity in the gun body.

[0005]

The invention according to claim 1 is provided with a gun main body having a plurality of parts assembled therein and having a cavity formed therein, and an air flow path provided in the gun main body. In the coating gun, a communication hole that connects the air flow passage and the hollow portion is formed in the wall forming the air flow passage.

According to a second aspect of the present invention, in the first aspect of the invention, the gap between the components exposed on the outer surface of the gun body is
The configuration is such that a seal member is provided. According to a third aspect of the present invention, in the first or second aspect of the present invention, an air opening / closing valve is provided in the middle of the air passage, and the communication hole includes the air opening / closing valve in the air passage. It is arranged at a position on the upstream side of. The invention of claim 4 is
The invention of any one of claims 1 to 3, wherein when the pressure of the air in the hollow portion of the gun body becomes higher than a predetermined value, the air in the hollow portion escapes to the outside of the gun body. A relief valve capable of performing the above is provided.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the flow rate of the pattern width adjusting air flowing through the air flow passage can be adjusted in the gun body by an operation from outside the gun body. In the coating gun in which the pattern width adjusting member is provided so as to penetrate from the inside of the cavity to the outside of the gun main body, the relief valve is provided inside the pattern width adjusting member.

[0008]

[Advantageous Effects of the Invention] [Invention 1] When high-pressure air is supplied from the air flow path into the cavity through the communication hole, when a liquid such as a solvent is sprayed at a high pressure on the outer surface of the gun body. In addition, even if the liquid tries to enter the cavity through the gap between the parts forming the gun body, the pressure of the high pressure air in the cavity reliably prevents the liquid from entering.

[Invention of Claim 2] Since the seal member is provided in the gap between the parts exposed on the outer surface of the gun body, the infiltration of the liquid into the gun body can be prevented more reliably. . [Invention of Claim 3] Since the communication hole is arranged upstream of the air on-off valve, that is, on the air pressure source side, even if the air on-off valve is closed, a high pressure is generated in the cavity. Air can be supplied. [Invention of Claim 4] By providing the relief valve, it is possible to prevent the pressure of the air in the cavity from becoming excessively high,
As a result, damage to the parts forming the gun body is prevented.

[Invention of Claim 5] Since the pattern width adjusting member is provided so as to penetrate from the inside of the cavity to the outside of the gun body, the air inside the cavity is provided inside the pattern width adjusting member. It is possible to provide a relief valve for allowing the air to escape to the outside. By thus incorporating the relief valve in the pattern width adjusting member, it is possible to reduce the number of parts and simplify the structure.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

The coating gun of this embodiment is mainly composed of a barrel 1.
By assembling 1 (a component constituting the gun body 10 which is a constituent of the present invention) and a grip 12 (a component constituting the gun body 10 which is a constituent of the present invention), a cavity portion 23 is formed inside. The gun main body 10 in the open state is formed, and the high voltage generator 13, the air on-off valve 14, and the paint on-off valve 15 are built in the gun body 10. When the trigger 16 is pulled rearward, the two on-off valves 14 and 15 are opened, and the paint, atomizing air, and pattern air are released.
Is discharged from the nozzle 17 at the front end of the high voltage generator 1
The paint electrostatically applied by 3 is atomized by the atomized air, and the pattern air is sprayed on the atomized paint.

The barrel 11 constituting the gun body 10 is long in the front-rear direction, and an opening / closing valve accommodating hole 18 penetrating between the front and rear end surfaces of the barrel 11 is formed therein. The paint opening / closing valve 15 is housed in the opening / closing valve housing hole 18, and the paint is supplied to the paint opening / closing valve 15 through a paint pipe 19 connected to the lower surface of the front end portion of the barrel 11. Further, a front accommodation chamber 20 for a high voltage generator is formed above the opening / closing valve accommodation hole 18 in the barrel 11 so as to open to the rear end surface of the barrel 11. Further, on both left and right sides of the opening / closing valve accommodating hole 18 in the barrel 11, the atomizing air flow passage 21 (air flow passage which is a constituent feature of the present invention) and the pattern air flow passage 22 (constituent feature of the present invention) extend in the front-rear direction. And the air flow path) which is Although not shown in the drawings, the nozzle 17 attached to the front end of the barrel 11 has a paint discharge port communicating with the paint opening / closing valve 15 and an atomizing air passage 21.
An atomizing air ejection port that communicates with the pattern air ejection port and a pattern air ejection port that communicates with the pattern air flow path 22 are formed.

The grip 12 has a hollow portion 23 formed therein for weight reduction. The opening on the front surface of the upper end portion of the grip 12 is joined to the rear end surface of the barrel 11, and the grip 12 and the barrel 11 are separated by a bolt 25 with a plate-shaped seal member 24 sandwiched between the joining surfaces. Fixed (see FIG. 2) so that the gun body 1
0 is configured. The space at the upper end of the cavity 23 of the grip 12 serves as a rear accommodation chamber 26 for the high voltage generator, which communicates with the front accommodation chamber 20 for the high voltage generator of the barrel 11, and both accommodation chambers 20, The high voltage generator 13 is housed in the space 26 without a large gap.

Inside the cavity 23 of the grip 12, a holder 27 is attached along the lower surface of the high voltage generator 13 and exposed to the outside from the rear surface of the grip 12 (see FIG. 3). A ring-shaped seal member 28 is mounted in the gap of the holder 27 on the outer surface of the grip 12 (see FIG. 3). As shown in FIG. 5, the holder 27
An on-off valve 14 for air is housed therein, and
Atomization air communication passage 29 (air passage which is a constituent feature of the present invention) and pattern air communication passage 30 for communicating the air opening / closing valve 14 with the atomization air passage 21 of the barrel 11 and the pattern air passage 22. (Air flow path which is a constituent feature of the present invention) is formed.

Further, the space in the holder 27 behind the valve opening of the on-off valve 14 for air serves as an air supply chamber 31 (air passage which is a constituent of the present invention). Further, inside the grip 12, an air supply pipe 32 (an air flow path which is a constituent feature of the present invention) having an upper end communicating with the air supply chamber 31 is provided. The lower end of the air supply pipe 32 has a bottom plug member 3 fixed to an opening at the lower end of the grip 12.
3 is connected to the air port 34, and the air port 3
An air supply hose (not shown) is connected to 4.
A ring-shaped seal member 35 is mounted in the gap between the opening of the grip 12 and the bottom plug member 33. When the air on-off valve 14 is opened, the air pressure-fed from an air pressure-feeding source (not shown) passes through the air supply hose, the air supply pipe 32, the air supply chamber 31, and the open valve opening in order, and then atomized. A flow passage passing through the air communication passage 29 and the atomized air flow passage 21, a pattern air communication passage 30 and a pattern air flow passage 22.
And is supplied to the nozzle 17 and is jetted from the atomizing air jet port and the pattern air jet port.

In the wall portion 27W (upper wall portion) which constitutes the air supply chamber 31 of the holder 27, from the inner wall surface of the air supply chamber 31 to the outer surface (upper surface) of the holder 27, that is, for the high voltage generator. Communication hole 3 penetrating to the surface facing the rear accommodation chamber 26
6 are formed (see FIG. 3). Due to the communication hole 36, the air supply chamber 31, that is, 21, 21 in the gun body 10
2, 29, 30, 31, 32 and the cavity 23 in the gun body 10 are in communication with each other so that air can flow. As a result, a part of the air supplied from the air pressure supply source to the air supply chamber 31 is always supplied to the cavity portion 23 through the communication hole 36.

A communication hole 36 on the outer surface of the holder 27 is provided.
Although the opening position of is close to the lower surface of the high voltage generator 13, a gap 37 that does not hinder the air flow is secured between them. Further, between the outer surface of the high voltage generator 13 and the inner wall of the high voltage generator front housing chamber 20,
Also, a gap 37 that does not hinder the flow of air is secured between the outer surface of the high voltage generator 13 and the inner wall of the rear accommodation chamber 26 for the high voltage generator. Then, these gaps 37 are formed by the large hollow portion 23 in the grip 12, and
The hollow portion 23 between the left and right side surfaces of the substantially rear half portion of the holder 27 and the inner wall of the grip 12 is communicated.

The pattern air communication passage 30 has a pattern width adjusting member 3 for adjusting the flow rate of the pattern air.
8 is interposed (see FIG. 5). The pattern width adjusting member 38 has an adjusting shaft 39 penetrating the cavity 23 between the inner wall of the grip 12 and the outer surface of the holder 27 and protruding to the outside rear of the gun body 10. By rotating the shaft 39, the opening degree of the pattern air communication passage 30 is increased or decreased to increase or decrease the flow rate of the pattern air. A ring-shaped seal member 40 is mounted in the gap between the grip 12 and the adjustment shaft 39.

Further, a relief valve 41 is built in the pattern width adjusting member 38. The relief valve 41 is for releasing the air in the cavity 23 to the outside of the gun body 10 when the pressure of the air in the cavity 23 of the gun body 10 rises to a predetermined value. As shown in FIGS. 5 and 6, the relief valve 41 has a discharge hole 42 formed in the adjustment shaft 39 for communicating with the hollow portion 23 and the outside of the gun body 10, and the valve seat is provided in the discharge hole 42. 43
And a spherical valve element 44 for opening and closing the valve seat 43 is housed in the discharge hole 42, and the knob 4 is provided at the rear end of the adjusting shaft 39.
5 is attached, and the valve body 4 is provided between the knob 45 and the valve body 44.
4 has a structure in which a spring 46 for urging the valve 4 in the valve closing direction is interposed. Normally, the valve element 44 is urged by the spring 46 so that the valve seat 43
And the relief valve 41 is kept closed. When the pressure of the air in the cavity 23 rises to a predetermined value, the valve element 44 is separated from the valve seat 43 by the pressure of the air in the cavity 23 against the elasticity of the spring 46, and the relief valve 41 is released. Opens.

A tubular cable holding member 47 is attached to the bottom plug member 33 in a penetrating manner, and a terminal of an external cable 48 connected to a power source (not shown) is attached to the cable holding member 47. The part is stuck. A ring-shaped seal member 49 is mounted in the gap between the bottom plug member 33 and the cable holding member 47. Inside the grip 12, an internal cable 50 (not shown) connected to the rear end of the high voltage generator 13 is routed, and the internal cable 50 is connected to the external cable 48 at the lower end of the grip 12. ing. Electric current is supplied to the high voltage generator 13 via both the cables 48 and 50.

Next, the operation of this embodiment will be described. When performing a cleaning operation for removing the paint adhering to the outer surface of the gun body 10, the air opening / closing valve 14 is kept closed, and the air is fed under pressure from the air pressure source to the painting gun. Keep it. By pumping this air, the gun body 1
The void portion 23 in 0 and the gap 37 along the outer surface of the high voltage generator 13 are filled with high-pressure air. In this way, if the cavity 37 and the gap 37 along the outer surface of the high voltage generator 13 are filled with high-pressure air,
Even if a high-pressure solvent is sprayed onto the gun body 10 with an air spray gun (not shown) for cleaning, the solvent causes a gap between the grip 12 and the barrel 11, which is a main component of the gun body 10, and the barrel 11. And the parts assembled to the barrel 11 and the gap between the grip 12 and the parts assembled to the grip 12 along the cavity 23 of the gun body 10 and the outer surface of the high voltage generator 13. It does not penetrate 37.

Moreover, the seal member 2 is provided in the gap between the exposed parts on the outer surface of the gun body 10.
4, 28, 35, 40, 49 are provided, so that the solvent passes through these gaps and the cavity 23 in the gun body 10
Intrusion into the gap 37 along the outer surface of the high voltage generator 13 is more reliably prevented. Also 21,2
Since the communication holes 36 for communicating the 2, 29, 30, 31, 32 with the cavity 23 are arranged upstream of the air on-off valve 14, that is, on the side of the air pressure source, the air on-off valve is provided. Even when the valve 14 is closed, the cavity 37 and the gap 37 along the outer surface of the high-voltage generator 13 can be filled with high-pressure air. Therefore, it is not necessary to open the air on-off valve 14 when cleaning the outer surface of the gun body 10.

When the air pressure in the cavity portion 23 of the gun body 10 and the gap 37 along the outer surface of the high voltage generator 13 becomes larger than a predetermined value, the relief valve 41 is opened and the cavity portion 23 is opened. Since the air in the gap 37 along the inside and the outer surface of the high voltage generator 13 is discharged to the outside of the gun body 10, the air in the cavity 37 and the gap 37 along the outer surface of the high voltage generator 13 is discharged. The pressure drops. As a result, the parts of the gun body 10 such as the grip 12 are damaged or the parts attached to the gun body 10 come off due to the excessive increase in the air pressure in the gun body 10. Is prevented.

Further, in the present embodiment, the pattern width adjusting member 38 uses the existing structure in which the pattern width adjusting member 38 is provided so as to penetrate from the inside of the cavity portion 23 to the outside of the gun body 10. Inside, a relief valve 41 for allowing the air in the cavity 23 to escape to the outside of the gun body 10.
Is provided. By thus incorporating the relief valve 41 in the pattern width adjusting member 38, the number of parts is reduced and the structure is simplified.

[Cables 48, 50 for high voltage generators]
Holding means] Next, the structure for attaching the external cable 48 for supplying a current to the high voltage generator 13 to the cable holding member 47 at the lower end portion of the grip 12 will be described in detail. Conventionally, as in the case of this embodiment, as a coating gun for electrostatics, a high voltage generator is housed inside the gun body, and an internal cable for supplying power to the high voltage generator is installed in the cavity of the grip. There is a structure in which the end portion of the external cable extended from the power source is fixed to the cable holding member provided at the lower end of the grip so that the internal cable and the external cable are connected.

In this type of electrostatic coating gun, the external cable is bent or twisted in the vicinity of the cable holding member as the operator grips the grip to move the coating gun or change the direction of the coating gun. Therefore, an external force is applied to the external cable in the direction of coming off the cable holding member. For this reason, the cable holding member is required to have a high holding function, but conventionally, as a means thereof, a ring-shaped hub nut externally fitted to the external cable is screwed onto the outer surface of the end portion of the cable holding member to externally fit the external cable. The C-shaped ring is pressed against the taper surface of the inner circumference of the end of the cable holding member by screwing in the hub nut to reduce the diameter, and the reduced C-shaped ring is bite into the sheath of the external cable, thereby removing the external cable. It had a structure that regulated directional movement.

However, in this conventional structure, since it is necessary to accommodate the C-shaped ring inside the cable holding member, the outer diameter dimension of the cable holding member becomes large,
In addition, since the hub nut is further fitted onto the cable holding member having the larger diameter, there is a problem that the outer diameter becomes significantly large as a whole.
In this respect, the present embodiment has the following structure in order to reduce the size. As shown in FIGS. 7 and 8, an external cable 48 is inserted into the cable holding member 47 through an opening at the lower end thereof, and a female screw is provided on the inner circumference of the lower end portion of the cable holding member 47. The part 51 is formed. Further, at the position above the female screw portion 51 on the inner circumference of the cable holding member 47, there is formed a circumferential ridge portion 52 projecting inward in the radial direction.
The lower surface of 2 is a tapered seal surface 52S. In the cable holding member 47, the tapered sealing surface 52S is provided.
The O-ring 53 is attached so as to abut against the bottom. Further, in the cable holding member 47, a C ring 54 that is in contact with the O ring 53 from below is mounted, and the lower surface of the C ring 54 has a tapered receiving surface 54.
It is assumed to be S. The stopper 55 is in contact with the tapered receiving surface 54S from below. Stopper 55
Is a form in which the elastic locking pieces 55B are projected upward from a plurality of positions on the upper edge of the cylindrical portion 55A. The upper end portion of each elastic locking piece 55B is a tapered biting portion 55C inclined inward toward the upper side, and the tapered biting portion 55C is brought into contact with the tapered receiving surface 54S from below. ing. Further, the cylindrical portion 5 of the stopper 55
A cylindrical pressing member 56 screwed into the female screw portion 51 is in contact with the lower end edge of 5A from below.

When the external cable 48 is assembled, the external cable 48 is inserted into the pressing member 56 while the pressing member 56 is screwed downward. When the sheath 48A of the external cable 48 is penetrated by the pressing member 56 and the protruding portion 52, the pressing member 56 is screwed upward.
Then, the pressing member 56 pushes up the stopper 55, and the elastic locking piece 55B pushes up the C ring 54 and the O ring 53. The O-ring 53 pushed up is pressed against the tapered seal surface 52S, and the diameter of the O-ring 53 is reduced by the inclination of the tapered seal surface 52S, so that the O-ring 53 is firmly attached to the outer circumference of the sheath 48A. As a result, the O-ring 53 seals between the inner circumference of the cable holding member 47 and the outer circumference of the external cable 48.

The elastic locking piece 55B of the stopper 55 pushed up by the pressing member 56 has its tapered biting portion 55C at the tapered receiving surface 54 of the C ring 54.
It is brought into contact with S, and the tapered biting portion 55C and the tapered receiving surface 54S are inclined to be reduced in diameter and deformed.
Then, the tapered biting portion 55C of each elastic locking piece 55B that has been reduced in diameter is caused to bite its obliquely inward end into the sheath 48A of the external cable 48. The direction of biting into the sheath 48A is obliquely upward, that is, the direction opposite to the direction in which the external cable 48 comes out of the cable holding member 47. Therefore, even if a downward pulling force is applied to the external cable 48, the taper-like biting portion 55C bites into the sheath 48A, so that the external cable 48 is reliably prevented from coming out downward.

As described above, in this embodiment, since the structure for holding the external cable 48 in the cable holding member 47 is merely the accommodation of the external cable 48 in the cable holding member 47, the structure is different from the conventional structure. When,
The outer diameter is smaller because the hub nut is not used, resulting in downsizing. [Other Embodiments] The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. Various modifications can be made without departing from the scope of the invention.

(1) In the above embodiment, the communication hole is arranged at a position upstream of the air opening / closing valve in the air flow path. However, according to the present invention, the communication hole is opened / closed in the air flow path. It may be arranged at a position downstream of the valve. In this case, the air opening / closing valve may be opened during the cleaning. (2) In the above embodiment, the relief valve for letting the air in the cavity escape to the outside of the gun body is provided. However, according to the present invention, the relief valve may not be provided.

(3) In the above embodiment, the relief valve is built in the pattern width adjusting member. However, according to the present invention, the relief valve can be provided separately from the pattern width adjusting member. (4) In the above embodiment, the coating gun having the function of adjusting the pattern width of the paint has been described, but the present invention can be applied to a coating gun having no pattern width adjusting function. (5) In the above embodiment, the paint is atomized by the atomizing air, but the present invention atomizes the paint pressurized by a pump to atomize it, and Pattern air may be added.

(6) In the above embodiment, an example in which the coating material is applied to an electrostatic coating gun that discharges the coating material under the electrostatic application is described. However, the present invention does not discharge the coating material without applying the electrostatic coating. It can also be applied to electrostatic coating guns.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a coating gun according to a first embodiment.

FIG. 2 is an enlarged vertical sectional view showing an assembly portion of a barrel and a grip.

FIG. 3 is an enlarged vertical sectional view showing an assembly portion of a grip and a holder.

FIG. 4 is a partially enlarged vertical sectional view of a grip.

FIG. 5 is an enlarged horizontal sectional view showing an assembly portion of a barrel and a grip.

FIG. 6 is a partially enlarged horizontal sectional view of a pattern width adjusting member and a relief valve.

FIG. 7 is an enlarged vertical sectional view showing an assembled portion of a grip, a plug and a cable holding member.

FIG. 8 is a partially enlarged vertical sectional view showing a holding structure for an external cable in a grip.

[Explanation of symbols]

10 ... Gun body 11 ... Barrel (the parts that make up the gun body) 12 ... Grip (parts that make up the gun body) 14 ... Air open / close valve 21 ... Atomization air flow path (air flow path) 22 ... Pattern air flow path (air flow path) 23 ... Cavity 24, 28, 35, 40, 49 ... Seal member 27W ... Wall portion that constitutes the air flow path 29 ... Atomizing air communication path (air flow path) 30 ... Pattern air communication passage (air passage) 31 ... Air supply chamber (air flow path) 32 ... Air supply pipe (air flow path) 36 ... Communication hole 38 ... Pattern width adjusting member 41 ... Relief valve

Claims (5)

[Claims] 1. A coating gun comprising a gun main body having a plurality of parts assembled therein and having a hollow portion secured therein, and an air flow passage provided in the gun main body, wherein the air flow passage is configured. A coating gun, wherein a communication hole for communicating the air flow path and the cavity is formed in the wall portion. 2. The coating gun according to claim 1, wherein a seal member is provided in a gap between the components exposed on the outer surface of the gun body. 3. An air on-off valve is provided in the middle of the air flow path, and the communication hole is arranged at a position upstream of the air on-off valve in the air flow path. The coating gun according to claim 1 or 2, which is characterized. 4. The gun body is provided with a relief valve capable of releasing the air in the cavity to the outside of the gun body when the pressure of the air in the cavity becomes higher than a predetermined value. The coating gun according to any one of claims 1 to 3, wherein: 5. A pattern width adjusting member, which is capable of adjusting a flow rate of air for adjusting a pattern width flowing through the air flow passage by an operation from the outside of the gun main body, is provided in the gun main body from inside the cavity. The coating gun according to claim 4, wherein the relief valve is provided inside the pattern width adjusting member.