JPH02265663A - Spray gun - Google Patents

Abstract

PURPOSE:To permit an easy cleaning by a method wherein an air spray pipe having an air spray orifice is made movable forward and rearward in the air spray direction and wherein the forward and rearward movement thereof is effected by difference in the pressures of the air sent pressurized into a front and a rear chamber. CONSTITUTION:A spray air reaches a spray air orifice 12 and an operation air reaches a rear chamber 9. By the switching action of a valve, the pressure of the rear chamber 9 is reduced and air is introduced into a front chamber 8. In doing so, a piston 6 is moved reaward with the accompanying rearward movement of an air pipe wall 13 formed integrally with the piston 6, whereby an air pipe orifice 14 provided in the air pipe wall 13 is communicated with the spray air orifice 12 inside a spray gun to permit the spray air to be shot out through an air injection pipe 2. When the air pipe wall 13 is moved rearward, a spray material orifice 18 is opened to shoot out the spray material. The permits an easy stoppage and restart of spray.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a spray gun.

[Prior Art] A spray gun is a device that injects a spraying material along with compressed air. This is commonly used for painting, spraying wall materials, etc.

As shown in FIG. 1, in this structure, the spraying material sent from the spraying material tank 91 to the front space 93 of the compressed air outlet S2 by gravity or other pressure is entrained with air by the jetting pressure of the compressed air. The material is ejected from the spray material spout 94. The start and stop of spraying is performed by opening and closing a valve provided in the middle of the compressed air jet pipe 95 or at the inlet of the main body.

Most viscous spray materials are sprayed using this method.

Recently, the exterior walls of buildings, etc. are often finished by spraying this spraying material, and spray guns are being used very frequently.

[Problem to be solved by the invention] Since the conventional spray gun has the structure shown in Fig. 1,
When the air is stopped, the spray material drops from the opening 94 and contaminates the workplace, scaffolding, etc. Since this contaminant hardens and is difficult to clean, the opening 94 is currently sealed by the operator with his/her finger to prevent the spray material from dripping. It is not surprising that such a seal is difficult in heavy spray guns.

It is no exaggeration to say that this is almost impossible in a multi-head spray gun in which there are a plurality of openings 94.

Furthermore, after the work is completed, the spraying material will remain inside the spray gun body. This spray material hardens over time, so if left unattended, it will harden inside the main body and cannot be used again. Therefore, be sure to clean the inside with water, etc. after completing work or when stopping.

Furthermore, when the compressed air is stopped, the pressure that the spraying material receives from the top and the pressure inside the air jetting pipe 95 are lower, so the spraying material does not reach the air jetting pipe 95.
It will fall within 5. Cleaning the inside of this air jet pipe is a very troublesome task. This is because it has to be disassembled and the inside cleaned.

Furthermore, in recent years, the aesthetic elements required for spraying finishes on exterior walls, etc. have been expanding more and more, and as natural stone-like finishes, geometric patterns, etc. are required, spray guns are becoming more and more popular. There is also a growing need for equipment to be equipped with multiple types of spray materials and to be able to switch between them in a short period of time.

In addition, the number of high-rise buildings has increased recently, and the beautiful surfaces made of sprayed material may be located quite far from the ground.

In such a case, the pattern is so small that it is hardly visible (inconspicuous) using the conventional spraying method.

For example, when spraying a natural stone look with a so-called 3-head gun, 3
The mixing ratio of colors is roughly fixed, but as in the past, 3
When all three nozzles are sprayed in succession, each color blob becomes smaller and less noticeable.

Therefore, in the spraying industry, there are spray guns that do not drop the spraying material when stopped and the spraying material does not seep into the air jet pipe, and even in high-rise buildings such as those mentioned above, natural stone looks are clearly visible. A spray gun that can produce this has long been desired.

[Means for Solving the Problems] In view of the above-mentioned current situation, the present inventor has completed the spray gun of the present invention as a result of intensive research, and its characteristics are as follows: A spray gun that ejects the spraying material sent to the front space of the spraying air outlet by the pressure of the spraying material from the spraying material outlet together with air by the ejection pressure of compressed air, the spray gun having the spraying air outlet. The air ejection pipe can move back and forth along the air ejection direction, and the back and forth movement is caused by a front chamber (in front of the piston) defined by a piston cooperating with the air ejection pipe in a cylinder provided in this direction. ) and the rear chamber (behind the piston), and the two air flow paths that provide this pressure difference can be switched manually or automatically from the outside, and the air When the jet pipe is in the most forward position, the spray material jet port is at the point where it is closed by the air jet pipe.

Here, the "spraying material tank" is a storage part that stores the spraying material, and is in communication with the spraying material spout.

"Blow air outlet" refers to the outlet of compressed air for blowing out the spray material, and "blow material outlet" refers to the frontmost opening from which the spray material is jetted. The blowing air outlet opens in the same direction as the spraying material outlet, and is located at the rear of the spraying material outlet. Therefore, a space exists between the spray material outlet and the spray air outlet, and this space is referred to as a "space in front of the spray air outlet."

The blowing air jetting pipe is movable back and forth along the blowing direction. This back and forth movement is achieved by moving a piston cooperating with the tube back and forth within the cylinder. Therefore, in the present invention, the air flow path communicating with each chamber in the cylinder is provided independently from the flow path communicating with the blowing air jet pipe so as to apply a pressure difference between the two chambers defined by the piston. Each air flow path that communicates with each chamber is connected to an external high-pressure air supply source such as an air compressor, and in the end, if you include the one that connects to the compressed air jet pipe, there are three flow paths. It will exist. Of these, the one that communicates with the two chambers in the cylinder can be switched manually or automatically. What communicates with the blowing air jet pipe is independent of this switching, that is,
This means that the structure is such that even when the blowing air jetting pipe itself closes the spraying material jetting port, air is jetted out from the compressed air jetting port.

Note that if the air supply source is stopped while the spray air pipe is in the rear position and the spray material outlet is open, the spray material may drop or the spray material remaining near the spray material outlet may drop. Problems such as solidification and blockage may occur, which defeats the purpose of the present invention. Therefore, when the air compressor, etc. is stopped, the blowing air pipe should be in the forward position to close the blowing material outlet. It goes without saying that the system should be designed in such a way that it does. Therefore, before operation, the compressed air jetting pipe is in a forward position due to the force of a spring or the like, and it is only necessary to move it backwards when air is taken in.

The air jet pipe is a pipe having a blowing air jetting port, through which the blowing air passes. It is provided with an air pipe opening for introducing blown air from the outside. Further, this air ejection tube is composed of an air tube tip portion, which is the tip portion thereof, and an air tube wall, and these can be slid a certain distance.

That is, even if the tip is stationary, only the air tube wall can move back and forth a certain distance.

The term "delay mechanism" refers to a mechanism that always causes the spray material outlet to open later than the air outlet. Although this mechanism is not particularly limited, for example, when the air pipe wall is moved backward by the piston, there is play, and the spray material closing port does not open until after it has moved a certain distance. The spray material closing port refers to a point where the spray air outlet closes the passage of the spray material.

Furthermore, by alternately sending compressed air into the two chambers of the cylinder, a large amount of the spraying material can be sprayed at once, resulting in a novel spray-painted surface.

Although the spray gun of the present invention has been described as having one spraying material outlet, the same applies to a spray gun having a plurality of spraying material outlets.

In the case of a plurality of spray guns, there are some cases in which the movement of the compressed air jet pipe is performed by a single switch, and cases in which the movement is performed by a switch provided in each individual spray gun. Alternatively, only one of the plurality of spraying material spouts may have the structure of the present invention.

[Example J] The present invention will be described in more detail below based on an example shown in the drawings.

FIG. 2 is a partial sectional view schematically showing the internal structure of the spray gun 1 according to the present invention. Inside the spray gun 1, an air jet pipe 2 is provided so as to be movable along the air jet direction, and its tip (left end in the drawing)
is the blowing air outlet 3. A spray material tank 4 is attached above. This figure shows the air jet pipe 2.
It is located at the front, and the blowing air outlet blocks the spraying material outlet 5.

The movable air jet pipe 2 is integrally constructed with a piston 6 provided on the rear side thereof, and the piston 6 moves forward and backward (left and right in the drawing) in a cylinder 7, which is a space provided in the spray gun 1. ) Move back and forth while keeping the two rooms separated. The front chamber 8 and the rear chamber S each have an air flow path 81
and 99 to a compressed air supply source, not shown.

The air sent into the air jet pipe 2 is also from this compressed air supply source, and the air flow path 21 for that purpose is
is in communication with the compressed air supply.

Next, the movement of the air pipe etc. will be explained.

At the previous stage of spraying, compressed air has not yet been introduced into the spray gun 1. At this stage, spring 1
0, the air jet pipe 2 is pushed forward. Air from compressor 11 is then introduced. At this time, the blown air and the piston actuation air may have the same pressure or different pressures.First, the blown air reaches the blown air opening 12, and the actuation air reaches the rear chamber 9.

At this stage, neither air nor spray material has been ejected yet.

Next, the pressure in the rear chamber e is lowered by switching the valve, and air is introduced into the front chamber 8. As a result, the piston 6 moves rearward, and the air tube wall 13, which is integral with the piston 6, moves rearward, thereby opening the air tube opening 14 provided in the air tube wall 13 into the interior of the spray gun. The blowing air is communicated with the blowing air opening 12 , and the blowing air is ejected through the air blowing pipe 2 . In addition, the air pipe wall 13
When it moves backward, it comes into contact with the end wall surface 17 that is integrally formed with the air tube tip 16 after moving a certain distance (play), and then moves backward together with the air tube tip 16. As a result, the spray material closing port 18 opens and the spray material is spouted out.

Next, when the introduction of actuation air moves from the front chamber 8 to the rear chamber 9, the ejection of the spraying material and air is stopped by the above-described reverse process.

FIG. 3 is a schematic flow sheet showing the air flow path.

Air from the compressor 11 is divided into three systems. One is led to the front chamber 8, one to the rear chamber 9, and the rest to the blow air opening 12 as blow air.

Each is provided with a pressure reduction and stop valve. Furthermore, the piping 81 to the front chamber 8 and the piping 99 to the rear chamber are respectively provided with three-way valves 19 and 20. By switching the three-way valves 19 and 20, the front chamber 8 and the rear chamber 9 are connected to communicate with a pressure source or the atmosphere.

This three-way valve is driven by a solenoid valve, which is switched at a predetermined time by a timer. for example,
For example, change the spray every 3 seconds, or spray for 2 seconds and stop for 5 seconds.

Of course, all of these switchings can also be performed manually. For example, a push button, a cock, etc.

Further, in the above example, a one-head gun (one spray port) was described, but the same applies to a multi-head gun, and all or part of the multi-head gun may be adapted to the present invention.

In particular, when spraying to create a natural stone look using a three-head gun, it is preferable to use one or two of the guns in this manner.

[Effect of the invention] The main features of the detailed explanation above are as follows.

■ Blow air and operating air are completely separate systems. This makes it possible to stop and start blowing without changing the blowing air at all.

■ Spraying can be easily stopped and started using the switching valve.

■ By using a timer, you can automatically spray intermittently, so you can spray the same amount of spray material in large chunks. This makes it possible to create large patterns that are impossible with conventional spray guns.

■ Since the blowout of the blowing air and the blowout of the spraying material are delayed in time, the phenomenon of bottle leakage does not occur.

5... Shot material spout A... cylinder 9... Rear room 11... Compressor 13...Air pipe wall 16...Air tube tip 18... Spraying material closing port 21...Air flow path 6...Piston 8...Anterior chamber 10...Spring 12...Blow air opening 14...Air pipe opening 17... End wall surface 19.20...three-way valve

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional example, FIG. 2 is a partial sectional view showing an embodiment of the present invention, and FIG. 3 is a schematic flow sheet showing an embodiment of the present invention.

Claims (1)

[Claims] 1. The spray material sent from the spray material tank to the space in front of the spray air outlet by gravity or other pressure is entrained with air by the jet pressure of compressed air and leaves the spray material outlet. In the spray gun, the air jet pipe having the air jet port is movable back and forth along the air jet direction, and the back and forth movement is caused by the air jet pipe being in a cylinder provided in this direction. This is done by the pressure difference between the air that is forced into two chambers, the front chamber (in front of the piston) and the rear chamber (behind the piston), which are defined by a piston that moves together with the piston. A sprayer characterized in that the flow path is switched manually or automatically from the outside, and when the air jet pipe is at the most forward position, the spray material jet port is closed by the air jet pipe. gun. 2. The air flow path in the air jet pipe is communicated by moving the air pipe wall of the air jet pipe to the rear side,
The spray gun according to claim 1, wherein the spray gun is shut off by moving forward. 3. The spray gun according to claim 1, wherein the spray material outlet is opened with a delay with respect to the air outlet by a delay mechanism. 4. The compressed air pipe connected to the two chambers partitioned by the piston is provided with a switching valve that is electrically operated by a timer. spray gun.