JPS6268563A - Spray gun - Google Patents

Abstract

PURPOSE:To smooth the operation of a needle valve and to enhance the handling property and operability of a spray gun, by providing a piston acting air pressure on the needle valve for opening and closing a pint emitting port. CONSTITUTION:When a trigger 10 is operated to retract a shaft lever 11, contacts S1, S2 are contacted to close a switch S and a solenoid valve is opened and high pressure air flows in an air flow passage 17 from an air source to be injected from an air emitting port 18 and a pattern hole 73 passing through a branched flow passage. The air flow passage 17 allows high pressure air to flow in the front part of the piston 5 of an air chamber 3 from the guide hole 62 provided to a base cylinder 41 to press the piston 5 rearwardly. Therefore, the spring force of the spring 61 energizing the piston 5 forwardly is reduced. When the trigger 10 is further pulled in this state, a needle valve 4 can be easily retracted over a desired drawing distance by high pressure air pressing the piston 5 and paint can be atomized and injected from a pint emitting port 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spray gun in which the needle valve for opening and closing the paint discharge port is provided with a piston on which air pressure acts, thereby making the needle valve operation smooth.

[Conventional technology]

In recent years, high viscosity coatings such as adhesives, particularly two-component adhesives, are often applied using a spray gun.

Such high-viscosity paints require high-pressure air to atomize, and the paints are also pumped under high pressure, so it is necessary to increase the force when pressing the needle valve that cuts the paint outlet. There is.

However, the conventional spray gun, as shown in Figure 6,
By increasing the spring force of the spring B used to press the needle valve A for cutting off the pressure-fed paint, leakage of air and paint is prevented.

[Problem that the invention seeks to solve]

However, with such conventional spray guns, the increase in spring force increases the operating force of the trigger, resulting in poor handling.
If used for a long period of time, fingers may become fatigued and may also cause M injury.

The present invention aims to provide a spray gun that can reduce the operating force of the needle valve and improve the handling and operability of the spray gun, based on the principle that a piston is provided in the needle valve and pressurized air is added to the front part of the piston. The purpose is

[Means for solving problems]

Hereinafter, one embodiment of the means of the present invention capable of achieving the above-mentioned objects and solving the problems will be described with reference to the drawings.

In the figure, a spray gun 1 houses a piston 5 provided in a needle valve 4 in an air chamber 3 formed in a spray gun body 2.

A trigger 10 is attached to the spray gun body 2, and in this embodiment, a shaft rod 11 is moved backward by the trigger 10 and conducts electricity to the spray gun body 2, and the spray gun body 2
A switch S consisting of a terminal fitting 12 which is insulated from
A clip-shaped connection terminal 1 is connected to the adjustment knob 13 that conducts to the
6 is used for conduction.

The spray gun main body 2 has a head 22 at the front end of a body 21.
It also has a pistol shape with a handle 23 at the rear end, and the trigger 10 is pivotally supported by a body 21 and hangs down in the space between the body 21 and the head 22, and by its operation, the needle The valve 4 and the shaft 11 can be moved backward.

The needle valve 4 opens the paint discharge port 6 formed at the tip of the center hole of the paint nozzle 26 screwed into the head 22 as it moves backward, and connects the center hole, the inner hole 27 of the head 22, and the inner hole. A paint flow path 3 consisting of a side hole 30 leading from 27 to a nipple 29
1, the paint is discharged. In addition, nipple 29 has
It is electrically connected to a paint supply device E such as a paint pump that pumps the paint.

The needle valve 4 protrudes into the space, and the piston 5 that slides in the air chamber 3 provided at the rear of the spray gun body 2 is provided at its rear end.

The air chamber 3 is formed by a cylindrical metal fitting 35 that is inserted into a through hole 34 provided in the handle 23 at the rear of the spray gun body 2.

The through hole 34 is a stepped hole having a small diameter portion at the front via a step, and the cylindrical metal fitting 35 includes a base tube 41 and a cap 42 screwed onto the rear end. Moreover, the base cylinder 41 is
A reduced diameter portion 45 is formed between a threaded portion 43 that fits into the stepped hole and a flange 44 that abuts the step via a seal, and an increased diameter portion 46 is provided at the rear end of the threaded portion 43. Further, the base tube 41 is formed with a hole 50 having a large diameter and opening at the rear end in the guide hole 49 extending from the front end, and the hole 5o is formed in the guide hole 49 extending from the front end.
The air chamber 3 is formed by screwing the cap 4z onto the internal thread of the rear end. Note that the cap 42 is provided with an air vent hole, and an adjustment screw 52 fixed with a lock nut is screwed into the center thereof.

On the other hand, the needle valve 4 has a plunger 55 supported in the guide hole 49 and a piston fitting 56 coaxially screwed together by a small diameter threaded portion provided at the rear end.

As shown in FIG. 2, the piston fitting 5G has a neck portion 59 that maintains a gap between the guide hole 49 and the bulge portion 57 that presses the seal ring that fits into the small diameter portion at the rear end of the plunger 55 at the front end. and a piston 5 that slides in the air chamber 3 are arranged in series. Also, the spring receiver 60 at the rear end of the piston 5 and the cap 4
A spring 61 is disposed between the inner surface of the needle valve 4 and the inner surface of the needle valve 4 to urge the needle valve 4 forward and seal the paint discharge port 6.

Further, a through hole 62 is formed in the reduced diameter portion 45 of the base cylinder 41, and the through hole 62 can communicate with the front part of the piston 5 of the air chamber 3.

Further, the conduction hole 62 is connected to an air passage 17 provided in the spray gun body 2.

The air flow path 17 includes a blind hole 65 that opens at the front surface of the handle 23 from a nipple 64 at the lower end of the handle 23, and an upright hole 67 that passes through the through hole 34 and leads to a guide hole 66 passing through the body 21.
From the tip of the guide hole 66, passing around the paint nozzle 26,
It consists of a hole 69- communicating with the air discharge port 18. Note that the guide hole 66 has a baffle plate 70 and a camping nut 7.
1. A branch flow path communicating with the pattern hole 73 of the air cap 72 is provided by the air cap 72 and the like. It should be noted that when approaching the cylinder 74 extending from the baffle plate 70,
An adjustment knob 77 for pattern air adjustment is attached which has a valve body 75 for controlling pattern air adjustment.

Further, a diagonal hole 79 is opened at the lower end of the handle 23 and diagonally intersects with the upright hole 67 and communicates with the blind hole 65.
The shaft rod 11 is attached to the slanted hole 79, and the terminal fitting 12 is attached to the diagonal hole 79.

The blind hole 65 is a stepped hole that forms a small diameter portion at the rear via a step 91 at approximately the center, and a large diameter portion whose front end is open has a flange that abuts the step 91 via a seal. A support fitting 94 having a small diameter is screwed in between the front end of the large diameter portion and the threaded portion forming the end fitting.

The shaft rod 11 is a pin body with a tapered guide portion at the rear end, and is inserted into the inner hole 95 of the support fitting 94, supported by a small diameter guide hole at the rear end of the support fitting 94, and protrudes rearward. do. The shaft rod 11 is supported at the front by a screw fitting screwed into the front end of the inner hole 95, and its front end projects beyond the screw fitting toward the trigger 10. The shaft 11 also has a stopper 9 provided on the shaft 11 at the back of the screw fitting.
By providing a spring 99 between the support fitting 7 and the peripheral wall behind the support fitting 94, the support fitting 94 is biased forward.

Note that the shaft rod 11, the support metal fitting 94, and the screw metal fitting are all made of tetraelectric metal materials, so that the cough shaft rod 11 is electrically conductive to the spray gun body 2.

In this example, the terminal fitting 12 is attached to the guide tube 100, and the guide W1100 is fixed to the adjustment knob 13 via the stem 102. Further, the adjustment knob 13 is screwed into a screw fitting 103 that fits into the lower end of the oblique hole 79 so as to be able to move forward and backward.

As shown in FIG. 3, the terminal fitting 12 has a small diameter base 10.
5 has a pin shape with a flange 106 at the lower end. The guide tube 100 is made of synthetic resin such as polyamide or polyacetal, and has a through hole 10 through which the base 105 is inserted.
7, a relatively long guide hole 1 into which the flange 106 is loosely inserted;
09 is installed in the small diameter portion above the diagonal hole 79 through a spring ring 110 using an O-ring, for example, which is screwed into its outer circumferential groove.
The guide cylinder 100 is steady rested. In addition, the stem 102 is attached to the lower end of the guide hole 109, and the stem 1
A spring 111 is inserted between 02 and the flange 106 to bias the terminal fitting 12 upward so as to be able to descend.

The lower end of the stem 102 is fixed to the adjustment knob 13, and a retaining ring 112 is fitted onto the stem 102.

Further, in the stem 102, a spring 114 is inserted between the upper surface of an O-ring 113, which is provided on the upper surface of the small hole of the screw fitting 103 through which the acid stem 102 passes, and seals the stem 102, and the stopper 112. inserted. Note that the spring 114
presses the O-ring 113, enhances the sealing effect between the stem 102 and the screw fitting 103, eliminates play in the handle direction of the stem 102, and adjusts the adjustment knob 13.
This prevents idle rotation.

Further, the terminal fitting 12, the spring 111, and the stem 102
The adjustment knob 13 is formed using a conductive material such as metal, while the guide tube 100 and the screw fitting 103 are formed using a non-conductive material such as polyacetal resin or polyamide resin. 12 etc. are insulated from the spray gun body 2. Therefore, the shaft rod 11 that is electrically connected to the spray gun body 2 and the terminal fitting 12 that is insulated from the spray gun body 2 come into contact with each other as the shaft rod 11 moves backward by pulling the trigger 10. A switch S is formed having contacts S1 and S2 for conducting.

The spray gun main body 2 and the adjustment knob 13 are configured to supply paint or air or both to the spray gun main body.
That is, the electric wire 14.15 for operation is connected to the electromagnetic valve (14.15) for controlling the supply of air and paint, and in this embodiment, the electromagnetic valve (2) is connected to a high-pressure air source P that supplies high-pressure air. .

The nipple 64 at the lower end of the handle 23 has a fitting 116,
Hose joint 12 for connecting a hose 119 that communicates with the high-pressure air source P via the solenoid valve V via a nut fitting 117
0 is connected, and the electric wire 14.15 is connected to the hose 119.
It passes through the interior and is taken out from the hose joint 120 to the outside.

Note that the electric wires 14 and 15 are included in one electric cord 19 covered with an outer jacket. Note that it is also possible to use an electric cord having a core wire and a sheathed wire surrounding the core wire, and use the core wire as one electric wire 14 and the sheathed wire as the other T-wire 15.

As shown in FIG. 4, the hose joint 120 has an upper cylinder part 122 at the upper end of a hexagonal part 121, and a joint part 123 at the lower end. The cord 19 can be inserted relatively densely and the hexagonal part 1
A notch a125 communicating with the groove 126 on the upper surface of the 21 is provided. Therefore, the electric cord 19 can pass through the cutout groove 125 and fit into the recess a12G. In addition, by screwing the nut fitting 117 into the threaded tube portion 122, the electric cord 18
is pressed and taken out from the hose 119 in an airtight manner. Note that a resilient seat plate 127 made of rubber, synthetic resin, or the like is interposed between the upper surface of the hexagonal portion 121 and the nut fitting 117.

Further, the electric cord 19 is inserted through the hose 119 as described above, and then taken out from its lower end in the same manner as shown in FIG. 5 and connected to the electromagnetic valve V.

One of the electric wires 14 is connected to the hexagonal portion 121 with screws or the like, and its periphery is covered with an insulating ring, insulating tape, or the like. Therefore, the electric wire 14 is electrically connected to the spray gun body 2 via the nut fitting 117, the joint 116, and the nipple 64.

Further, the other electric wire 15 has a connecting terminal 16 joined to its end.

As shown in FIG. 4, the connection terminal 16 has a clip shape made of, for example, a spring material, and is connected to the U to which the electric wire 15 is connected.
The leg end of the bent portion 129 of the letter is shaped like a clip, with grip portions 130 and 130 curved in an arc for holding the neck portion of the m-section knob 13. Therefore, the connection terminal 16 can be easily attached to and detached from the adjustment knob 13 by expanding the grip portion 130, and conduction can be established by the attachment. Therefore, when removing the hose 119, the connection terminal 16 can be easily removed.

Further, the connection terminal 16 can rotate relative to the adjustment knob 13, making adjustment of the adjustment knob 13 easy.

In addition, if the connection terminal 16 is a clip-shaped one,
There are various types of grips, such as those in which the grip part 130 can be opened and closed using a torsion spring, and those in which the spring piece is bent into a V shape and can be inserted and detached into the hole provided in the adjustment knob. Aspects can be used.

By operating the trigger 10, the shaft rod 11 is moved backward, and its contact S1 contacts the contact S2 at the upper end of the connecting fitting 12 to conduct electricity, thereby closing the switch S.

Therefore, the contact S1 is connected to the spray gun body 2, the joint 116,
Pass through the nut fitting 117 and the hose joint 120 and I! Nine electric wires 14, the terminal fitting 12, a spring 111, a stem 102, and t! A short circuit is made between the electric wire 15 connected via the one-node knob 13, and the solenoid valve (2) is opened. Therefore, high-pressure air from the air source passes through the magnetic valve V, the hose 119, etc., flows into the air flow path 17, and enters the air outlet 18.
, is ejected from the pattern hole 73 passing through the branch flow path.

In addition, the air flow path 17 is connected from a conduction hole 62 provided in the base cylinder 41.
High-pressure air flows into the air chamber 3 in front of the piston 5 to pressurize the piston 5 rearward. Therefore, the spring force of the spring 61 that urges the piston 5 forward is reduced.

By further pulling the trigger 10, the needle valve 4 is retracted via the plunger 55, and the paint outlet 6 is opened, so that the paint from the paint supply device E passes through the paint flow path 31 and becomes the paint. It flows out from the discharge port 6 and is atomized and ejected by air. In this way, the piston 5 is pressurized rearward by high-pressure air, so it can be easily pulled by the trigger 10.

Furthermore, the spring force of the spring 61 can be increased, the sealing force of the needle valve 4 can be improved, and high-pressure paint can be easily cut into pieces. Furthermore, it becomes possible to finely adjust the pulling distance of the needle valve 4, thereby increasing the coating accuracy.

Further, the high pressure air can be turned off by a solenoid valve V operated by a switch S formed by a shaft rod 11 and a terminal fitting 12. Further, the spring force of the spring 99 that biases the shaft rod 11 can be set to be small. Therefore, high-pressure air can be cut by pulling the shaft rod 11 with a low spring force, reducing the operating force of the trigger IO. It also eliminates the impact when opening the air on-off valve, which has a large spring force, and prevents excessive pulling due to the impact. Therefore, it is possible to prevent the needle valve 4 from being pulled as usual when the shaft rod 11 is operated. As a result, it becomes easy to discharge high-pressure air, improving operability. In addition, by reducing the operating force, finger fatigue is reduced and injuries such as social injury are prevented.

The air chamber 3 also has an air on-off valve, in this example, the solenoid valve V.
Since the pipe 1ffi is connected to the downstream side, air pressure can be applied to the piston 5 only when the trigger 10 is operated, and the paint discharge port 6 is closed by a strong spring force when the trigger 10 is not operated.

Furthermore, since the electric wires 14.15 are electrically conductive within the hose 119, damage to the electric wires 14.15 due to dragging of the hose 119 is prevented. Also, using the clip-shaped connection terminal 16,
Since the electric wire 15 is attached, the film is easily deposited, and the attachment and detachment of the hose 119 is easy, and even when attached to the adjustment knob 13, it is made relatively rotatable, making it easy to adjust the knob. .

Further, by using a sheathed wire as the electric wire 14, 15, even if the outer sheath is damaged, the danger associated with 1llii electric current can be prevented by connecting the sheathed wire to the ground side.

In the spray gun of the present invention, by increasing the area of the piston 50, etc., the needle valve 4 can be configured to open when the trigger 10 is operated. Further, in the gun having the conventional air on-off valve A shown in FIG. 6, various modifications can be made, such as forming an air chamber 3 downstream of the air on-off valve II+ in the air flow path to form the gun of the present invention.

〔Effect of the invention〕

In this way, the spray gun of the present invention slidably accommodates the piston provided in the needle valve that closes the paint discharge port in the air chamber formed at the rear of the spray gun body, and connects the air chamber to the air flow path. Therefore, the air pressure acting on the piston can apply a backward force to the needle valve while pressurized air flows through the air flow path, that is, when the air on/off valve opens and closes. Therefore, even when a strong forward force is applied to the needle valve by the spring, the pulling force of the trigger can be reduced. Therefore, j411
In addition to regular paints, even when using high-viscosity 9-agents that require high-pressure pumping, it ensures sealing with the needle valve, reduces the pulling force, and improves the operability of the gun. In addition, by reducing the attraction force of the trigger, it becomes possible to adjust the pulling distance of the needle valve, increasing breeding efficiency and improving coating quality.

Furthermore, as in this embodiment, when the air on-off valve is also opened and closed by a switch consisting of a shaft rod and a terminal fitting,
The use of high-pressure air becomes easier, and the gun's ease of handling can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view illustrating a piston, and FIG. 3 is a perspective view schematically showing a shaft rod for forming a switch that can be used in the spray gun of the present invention. 4 is a perspective view schematically showing the electric wire arrangement that can be adopted in the spray gun of the present invention, FIG. 5 is a diagram showing one state of use, and FIG. 6 is a schematic diagram showing a conventional spray gun. FIG. 2--Spray gun body, 3-Air chamber, 4-Needle valve, 5--Piston, 6-Paint discharge port, 10-
-Trigger, 17--air flow path.

Claims (1)

[Claims] (1) An air chamber is formed at the rear of the pistol-shaped spray gun body, and is urged forward by a spring to close the paint discharge port of the spray gun body, and is pressed by the trigger of the spray gun body to close the paint discharge port. A spray gun in which a piston that slides the air chamber is formed at the rear end of an opening needle valve, and a front part of the air chamber is connected to an air passage provided in a spray gun body.