JPH0975791A - Spray gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of air from the joint between an air cap and the main body of a spray gun by the cap, to improve the working environment and to facilitate the detachment of the cap. SOLUTION: An air cap provided with a blowoff hole for discharging blowing air to atomize a paint in the center and a hole for discharging the air for adjusting the pattern of the atomized paint is furnished to a protrusion 3 to be provided at the front end of the main body of a spray gun through a connecting cylinder 4. An inside thread part 13 to be screw-joined to the outside thread part 9 of the protrusion 3 is provided at the rear of the base 12 of the connecting cylinder 4 extending rearward from an inside thread part 11 to be engaged with an outer flange 10 furnished to the cap. A front inward flange part 16 to be held between the outer flange and inner flange is formed on the front end of a cylindrical shell 15 to be inserted into the base in the connecting cylinder 4, and further a seal member forming a rear inward flange part 17 to be brought into contact with the front of the protrusion when pattern adjusting air passes is arranged on the rear end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray gun in which an air cap is attached to a front end of a spray gun main body, which can prevent air from leaking from a joint between the air cap and the spray gun main body, and perform inspection and cleaning. The present invention relates to a spray gun that can easily disassemble and assemble an air cap at a time.

[0002]

2. Description of the Related Art With regard to a so-called air spray gun for coating paint in the form of a mist by passing high pressure air, a conventional air spray gun is provided which encloses a nozzle for blowing out paint and has a plurality of holes for discharging air. It is attached to the front end of the gun body.

[0003] In this air cap, since the scattered paint adheres to an outlet or the like, the air flow passage is easily clogged, and the air cap is easily removed from the spray gun body. The members were joined.

[0004]

However, when an air cap is connected by using a union nut, air leaks from the screw portion of the union nut, and in particular, the screw thread is deformed by repeated attachment and detachment, and Leakage becomes more severe and becomes unusable.

In order to solve one end of such a problem, for example, as shown in FIG. 6, an outer peripheral portion c is brought into close contact with an inner hole b located behind a screw portion s of a union nut a and a spray gun main body. It has been proposed to provide an L-shaped packing g having a flange f that contacts the front face e of d.

In the above-mentioned proposal, air leakage from the screw portion s is reduced, but the outer peripheral portion c of the packing g is fitted into the inner hole b of the union nut a to form the air cap h and the union nut a. When disassembling, the packing g is also elastically deformed from the inner hole b and taken out through the screw portion s. By repeating such elastic deformation of the packing g, the outer peripheral portion c and the flange portion f are deformed and damaged, so that between the outer peripheral portion c and the union nut a and between the flange portion f and the spray gun body. There is a risk that air gaps may occur during the painting operation due to gaps.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spray gun which can eliminate air leakage from a joint portion between an air cap and a spray gun main body and can ensure the safety of a painting operation.

[0008]

According to the present invention, there is provided a central blow-off hole for discharging spray air for atomizing paint, and a pattern adjusting hole for discharging pattern adjustment air for adjusting the pattern of atomized paint. A spray gun that separates the blow-out air and the pattern adjustment air by attaching an air cap provided with a joint to a projection provided at the front end of the spray gun body by a joint tube, wherein the joint tube has an outer periphery of the air cap. An inner threaded portion engaging the front surface of the outer flange portion provided on the surface, and a rear portion of the base extending beyond the outer flange from the inner flange portion to an outer thread portion on an outer periphery of the projection of the spray gun body. A screw portion is provided, and a front end of a cylindrical body inserted into the base of the joint tube, before being sandwiched between the outer flange portion and the inner flange portion. Inside Come flange portion is formed, moreover a spray gun formed by arranging a sealing member forming an inward flange portion after the contact with the front surface of the protruding portion of the spray gun body when passing through the pattern adjusted air to the rear end.

[0009] The connecting cylinder may be provided on the inner surface of the base with a concave inner peripheral surface having substantially the same length as the body of the seal member and into which the body is inserted. The inward flange portion may be formed such that the tip portion is always in contact with the front surface of the protrusion.

Further, the sealing member may be a static fit in which the body is fitted to the inner peripheral surface of the base body such that the sealing member can be easily pulled out from the joint cylinder. A small gap may be provided between the surface.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, a spray gun 1 has an air cap 4 attached to a cylindrical projection 3 provided at a front end of a spray gun body 2 by a connecting cylinder 5.

The spray gun body 2 guides high-pressure air flowing from an air inlet 21 of the handle 20 to the projection 3 through an air flow passage 22 passing through the spray gun body 2. , An air valve 24 that is opened and closed by the operation of the trigger 23 is interposed.

The paint sent from the paint inlet passes through a paint passage 26 in which a paint opening / closing valve 27 is interposed. The paint passage 27 is more than the protrusion 3 arranged at the front end of the spray gun body 2. It communicates with a nozzle hole 29 that is opened at a protruding tip portion 28. The paint on-off valve 27 opens and closes its valve body in synchronization with the air valve 24 by operating the trigger 23.

The air passage 22 is formed in the projecting portion 3 by a spraying air flow path 31 through which the paint is atomized and blown by the blowing air B, and a paint sprayed outside the spraying flow path 31. It is branched into a pattern adjusting air flow path 32 through which a pattern adjusting air C for adjusting a pattern flows. A pressure adjusting valve 33 is interposed in the pattern adjusting air passage 32.

The air cap 4 is a hollow cylindrical body having a hole at the center, and is mounted on the axis of the projection 3 by the joint cylinder 5 fitted to the air cap 4 and the projection 3 as described above. .

As shown in FIG. 2, the air cap 4 has an inner hole 35 surrounding the distal end portion 28 of the spray gun main body 2, and is in communication with the blowing air flow path 31. Accordingly, an annular blowout hole 6 surrounding the nozzle hole 29 is formed between the outer peripheral surface of the distal end portion 28 and the inner peripheral surface of the inner hole 35.

Further, the air cap 4 is provided with a plurality of pattern adjusting holes 7 through which the joint cylinder 5 is connected, which can inject air toward the front on the axis of the nozzle holes 29 communicating with the pattern adjusting air flow path 35. It is formed. An air reservoir 37 for connecting the pattern adjusting air flow path 35 and the pattern adjusting hole 7 to each other is formed inside the joint tube 5.

In order to connect the connecting cylinder 5 to the air cap 4 and the projection 3 of the spray gun main body 2, the projection 3 is provided with an external thread portion 9 having an external thread screwed therein.
Is provided at its rear end with an outer flange portion 10 protruding outward from the outer peripheral surface in the circumferential direction.

The splicing tube 5 has an inner flange portion 11 having a back surface 11a abutting on a front surface 10a of the outer flange portion 10 of the air cap 4, and a cylindrical base 12 extending rearward from the inner flange portion 11. And, at the rear of the base 12, there is provided an internal thread portion 13 screwed to the external thread portion 9 of the projection 3.

Accordingly, the connecting cylinder 5 is a so-called union nut having an inner flange portion 11 which engages with the outer flange portion 10 of the air cap 4 and an inner thread portion 13 which can be screwed to the outer thread portion 9 of the projection 3. Is formed.

A seal member 14 is loaded in the joint tube 5. As shown in FIGS. 2 and 3, the sealing member 14 has a cylindrical body 1 that is inserted into the inner peripheral surface 12 a of the base 12.
5, and a front end of the body portion 15, that is, an inward flange portion 16 extending radially inward toward the air cap 4 side, has a rear end,
That is, the inward flanges 17 extending inward in the radial direction are formed on the protruding portion 3 side, and have a U-shaped cross section.

In this embodiment, the body 15 is
The seal member 14 is inserted and fitted between the inner peripheral surface 12a of the first and second inner peripheral surfaces 12a so that the seal member 14 can be easily pulled out from the joint tube 5.

The connecting tube 5 is made of an elastic material having an airtightness using rubber or a synthetic resin material such as nylon or Teflon. Teflon is particularly preferably used.

The seal member 14 is provided with the front inward flange 1.
6 is sandwiched between the front surface 10a of the outer flange portion 10 and the rear surface 11a of the inner flange portion 11, while the rear surface of the rear inward flange portion 17 is located on the front surface of the projection 3 of the spray gun body 2. Hang along 3a.

As shown by the solid line in FIG. 2, the rear inward flange portion 17 may be formed so as to lightly abut the front surface 3a of the projection 3 so that the front end portion always contacts the front surface. Further, as shown in FIG. 5, the pressure of the pattern adjusting air C flowing through the air reservoir 37 and the air flow thereof cause the subsequent inward flange 1
The rear surface 17a may be provided with a small gap F such that the rear surface 17a can be in close contact with the front surface 3a of the projection 3 by being pressed as indicated by the dashed line.

However, by operating the trigger 23, the air valve 24 is opened and the air flowing through the air flow path 22 from the air intake 21 is partially discharged.
1 and blows out from the blowout hole 6 around the nozzle hole 29.
Further, the paint is operated by operating the trigger 23, and the paint opening / closing valve 27
Is opened, and is atomized together with the air jet from the blow-out hole 6 and jetted from the nozzle hole 29.

The air branched from the air flow path 22 and flowing through the pattern adjustment flow path 32 is adjusted in air pressure by a pressure adjustment valve 33, passes through an air reservoir 37 formed by the connecting cylinder 5, and passes through an air hole of the air cap 4. The ink is discharged from the pattern adjusting hole 7 through the hole 36. The adjustment of the paint pattern is performed by adjusting the pressure of the pattern adjustment air by operating the pressure adjustment valve 33.

As described above, the sealing member 14 is loaded inside the connecting tube 5, and the sealing member 14 has the front inward flange 16 sandwiched between the outer flange 10 and the inner flange. Further, the body portion 15 is inserted into the base 12 of the connecting cylinder 5, and further, the pattern adjusting air C
Flow through, the subsequent inward flange 17 becomes the protrusion 3
Is held in close contact with the front surface 3a.

Therefore, the pattern adjusting air C is allowed to flow from the spray gun body 2 toward the air cap 4 inside the sealing member 14, in other words, without the pattern adjusting air C touching the connecting pipe 5. Thereby, the inside and outside of the joint between the joint tube 5 and the air cap 4 and the joint between the outer flange portions 10 and 11 and the joint tube 5 and the protrusion 3 are formed. It is possible to prevent air leakage from between the screw portions 9 and 13.

Further, since the body 15 of the seal member 14 is loosely fitted in the base 12 of the joint tube 5, the seal member 14 is not deformed even when the joint tube 5 is removed from the projection 3. The seal member 14 can be easily disassembled in a state where the seal member 14 is fitted on the outer flange portion 10 of the air cap 3, and the seal member 14 is not damaged even if the seal member 14 is frequently disassembled and cleaned.

FIG. 4 shows another embodiment. In this example, as shown in FIG. 4, the connecting cylinder 5 </ b> A has a length substantially equal to the length of the body 15 of the sealing member 14 on the inner surface 18 of the base 12, and is further larger than the diameter of the inner surface 18. Is provided via a step 39 extending radially. By providing such a concave inner peripheral surface portion 19, the axial movement of the seal member 14 with respect to the connecting cylinder 5A can be prevented, and a more stable air leakage treatment can be performed. Further, in this example, the body portion 15 is inserted into the joint cylinder 5A with a small gap G of 0.5 mm or less with respect to the concave inner peripheral surface portion 19. As described above, the present invention can be modified into various aspects.

[0032]

As described above, the spray gun according to the present invention having the above-mentioned structure allows the connection between the joint tube and the spray gun body and the connection between the joint tube and the air cap with a single sealing member. It is possible to prevent air from leaking from the part, improve the safety of painting work and improve the working environment, and it is necessary to remove the sealing member like the conventional structure when disassembling and cleaning the air cap and the connecting pipe Therefore, the deformation of the seal member, which causes damage at the time of removal, can be eliminated, and the mounting and dismounting operation can be easily performed, so that the work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an enlarged main part thereof.

FIG. 3 is a perspective view illustrating a seal member.

FIG. 4 is a cross-sectional view showing another embodiment.

FIG. 5 is a cross-sectional view showing another embodiment.

FIG. 6 is a sectional view showing a conventional technique.

[Explanation of symbols]

 Reference Signs List 2 spray gun main body 3 projection 3a front surface 4 air cap 5, 5A connecting cylinder 6 blowout hole 7 pattern adjustment hole 9 outer screw portion 10 outer flange portion 11 inner flange portion 12 base 12a inner peripheral surface 13 inner screw portion 14 seal member 15 Body 16 Inward flange in front 17 Inward flange after rear 18 Inner surface 19 Concave inner peripheral surface B Blowing air C Pattern adjusting air

Claims (4)

[Claims] An air cap provided with a central blow-off hole for discharging spray air for atomizing paint and a pattern adjusting hole for discharging pattern adjustment air for adjusting a pattern of atomized paint is connected to a joint tube. A spray gun that separates the blown air and the pattern adjustment air by being attached to a projection provided at the front end of the spray gun main body, wherein the joint tube has an outer flange portion provided on an outer peripheral surface of the air cap. At the rear of the base extending beyond the outer flange from the inner flange engaged with the front surface to the rear, there is provided an inner screw portion screwed to an outer screw portion on the outer periphery of the projection of the spray gun main body, and Inside the tube, at the front end of the cylindrical body inserted into the base of the connecting tube, an inward flange portion is formed before being sandwiched between the outer flange portion and the inner flange portion, Moreover A spray gun having a seal member that forms an inward flange after contacting the front surface of the projection of the spray gun body when the pattern adjustment air passes through the rear end. 2. The joint tube according to claim 1, wherein the inner surface of the base is provided with a concave inner peripheral surface portion having substantially the same length as the body portion of the seal member and into which the body portion is inserted. Item 1. A spray gun according to item 1. 3. The spray gun according to claim 1, wherein the rearwardly directed inward flange portion is always in contact with the front surface of the protruding portion. 4. The spray gun according to claim 1, wherein said seal member is inserted with said body portion having a small gap between said body portion and an inner peripheral surface of said base.