JPH0428957B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) TECHNICAL FIELD This invention relates to handheld pneumatic tool devices.

(Prior Art) Conventionally, hand-held air tool devices consisting of hand-held air tools such as air spray guns and air sanders, air hoses that supply compressed air to the tools, and compressed air sources have been widely used in the automobile manufacturing industry, shipbuilding industry, and construction industry. These hand-held air tools, such as air spray guns, are widely used in the industry, but when high-pressure air and paint are ejected from their respective nozzles, static electricity is generated in the gun head that houses these nozzles. (Because the air hose is generally made of an insulating material such as synthetic resin, it accumulates on the charged parts of the air spray gun and on the paint inside the air spray gun.) If static electricity builds up in this way, there is a risk of sparks, especially when cleaning operations are carried out in which white gasoline is sprayed with an air spray gun in a closed room with poor ventilation, such as in a car body repair shop or inside a ship's hull in the shipbuilding industry. In this case, the spark may cause a fire.

Therefore, it is known that a metal wire is embedded in a hose body that connects a compressor and a tool, and a ground terminal is attached to a connecting fitting on the compressor side of the hose body (see Japanese Utility Model Application Publication No. 127716/1983).
Also, as stated in Special Publication No. 54-83,
In addition to incorporating a ground wire within the hose body,
It is also known to provide a conductive paint film on the end of the hose body or at a portion where the fitting faces the end of the hose body to ensure a conductive connection.

(Problem to be Solved by the Invention) However, in the conventional hand-held pneumatic tool device, the connection structure between the hose and the joint is such that the hose body is not connected until the conductive member embedded in the hose contacts the joint fitting or the end surface of the hose body. After inserting the hose into the hose insertion part of the fitting, the diameter of the socket of the fitting is reduced to connect the two, which makes the conductive connection work troublesome, and also causes problems due to plastic deformation of the fitting. Since the hose main body and the fitting are connected by means of a hose, the fitting has to be discarded if the hose becomes unusable due to damage or the like, which is uneconomical. Further, when the hose body and the fitting are connected, the conductive member cannot be brought into sufficient pressure contact with the fitting, making it impossible to establish a reliable conductive connection.

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a hand-held pneumatic tool device that has a simple structure and can provide reliable conductive connections.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a hand-held pneumatic tool that includes a charged portion and a compressed air intake that is electrically connected to the charged portion; A compressed air hose whose front end is connected through a first joint, and whose rear end is connected through a second joint, and which is electrically grounded by a ground wire connected to the second joint. a compressed air source having a compressed air outlet; The front and rear ends of the conductive material are made to protrude from the front and rear end surfaces of the hose, while the first and second joints are conductive joints,
Each of the first and second joints is provided with an inner circumferential surface engaging portion and an outer circumferential surface engaging portion that engage with the inner circumferential surface and the outer circumferential surface of the compressed air hose, and both engaging portions are threaded in the same thread direction. The hose is screwed and fixed to the inner circumferential surface engaging portion and outer circumferential surface engaging portion of the first and second joints, respectively, and the front and rear ends of the metal conductive material are connected to the first and second joints. It is characterized in that the two joints are pressed together and both joints are electrically connected.

(Function) In the present invention, after the compressed air hose is pushed between the inner peripheral surface engaging portion and the outer peripheral surface engaging portion of the first joint or the second joint, when the joint is rotated with respect to the hose. Since the threads carved on the inner circumferential surface engaging portion and the outer circumferential surface engaging portion are threaded in the same direction, threads are formed on the inner and outer circumferential surfaces of the hose made of synthetic resin, and the hose is inserted into the joint. The metal conductive material that enters the hose and protrudes from the end surface of the hose comes into pressure contact with the conductive joint, thereby ensuring electrical continuity between the metal conductive material and the joint.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In Figures 1, 2, 3, and 4, 1 is an air spray gun as a hand-held air tool device made of a conductive material, and this air spray gun 1 is
It consists of a gun body 2 and a paint container 4 fixed to the gun body 2 via a nipple 3. Gun body 2
A gun head 5 with a built-in paint spray nozzle (not shown) is attached to one end, and when compressed air and paint are sprayed from the gun head 5, static electricity is generated, and this static electricity acts as a charged part 6. It accumulates in the gun body 2, the nipple 3, the paint container 4, and the paint in the paint container 4. A grip portion 7 is formed at the other end of the gun body 2, and a trigger 8 for opening and closing the nozzle is attached to the center of the gun body 2.

An air passage 9 is formed inside the gun body 2 as shown in FIG. It is open at the end. As a result, the compressed air intake port 10 is electrically connected to the charged portion 6. The compressed air intake port 10 has a nipple 11 made of a conductive material.
is screwed in.

In FIG. 3, reference numeral 12 denotes a cylindrical hose body made of synthetic resin, for example, soft vinyl, and inside this hose body 12 there is a spiral hose extending from the front end to the rear end, that is, over the entire length. A continuous metal wire 13 (metal conductive material) as a conductive material is buried. One end 14 and the other end 15 of this metal wire 13 protrude from front and rear end surfaces 16 and 17 of the hose body 12. These protruding portions are bent along the circumferential direction of the hose body 12 so as to be substantially parallel to the front and rear end surfaces 16 and 17. The hose main body 12 and the metal wire 13 described above constitute a compressed air hose 18 as a whole.

In FIG. 4, 19 is a union sleeve made of a conductive material, and this union sleeve 19
has a through hole 20 extending in the axial direction therein. A flange 21 projecting outward is formed at one end of the union sleeve 19, and one end surface of the flange 21 serves as an engagement surface 22 forming a part of a spherical surface. A fastening portion 23 that projects outward is formed in the center of the union sleeve 19, and this fastening portion 23 engages with a fastening tool such as a spanner. The other end of the union sleeve 19 has a threaded portion 24 having a thread formed on its outer periphery. Reference numeral 25 denotes a union nut made of a substantially cylindrical conductive material, and this union nut 25 is screwed and fixed to the threaded portion 24 of the union sleeve 19. A threaded hole 26 having an inner diameter larger than that of the threaded portion 24 is formed inside the union nut 25, and the thread of the threaded hole 26 and the thread of the threaded portion 24 are formed in the same thread direction, for example, right-handed. They are also formed at equal pitches. And the compressed air hose 1
The front end of 8 is connected to the threaded portion 2 of the union sleeve 19.
4 and the threaded hole 26 of the union nut 25. That is, the union sleeve 19
The threaded portion 24 is an inner peripheral surface engaging portion that is threadedly engaged with the inner peripheral surface of the compressed air hose 18, and the threaded hole 26 of the union nut 25 is an outer peripheral surface engaging portion that is threadedly engaged with the outer peripheral surface of the compressed air hose 18. This is a surface engaging portion.

The front end of the compressed air hose 18 is connected to the threaded portion 2.
4 and the threaded hole 26, first push the front end of the compressed air hose 18 slightly between the threaded portion 24 and the threaded hole 26, and then push the union nut 25 and the union sleeve 19 together. It is rotated integrally with respect to the compressed air hose 18.
At this time, as mentioned above, the compressed air hose 18 is made of soft vinyl, and since the threaded portion 24 and the threaded hole 26 are equally spaced in the same direction, union sleeves are attached to the inner and outer circumferential surfaces of the compressed air hose 18. 19. Even if the union nut 25 is rotated manually, a thread can be easily formed, and the front end of the compressed air hose 18 has a threaded portion 24 and a threaded hole 26.
It gets in between. When the metal wire 13 and the union nut 25 are electrically connected to each other by press-contacting the one end 14 of the metal wire 13 to the stepped surface 27 of the union nut 25, the rotation of the union nut 25 and the union sleeve 19 is stopped. . In this way, the front end of the compressed air hose 18 is held between the threaded portion 24 and the threaded hole 26, thereby sealing between the union sleeve 19 and the union nut 25.

Reference numeral 28 denotes a union nut made of a conductive material, and this union nut 28 is rotatably connected to one end of the union sleeve 19.
This union nut 28 is attached to the stepped surface 29 of the flange 21 of the union sleeve 19.
When the union sleeve 19 is caught, the union sleeve 19
It is prevented from slipping out. A screw hole 30 is formed in the union nut 28, and this screw hole 3
0 and a threaded portion 31 formed on the nipple 11 shown in FIG. 2 are screwed together. Nipple 1
1 is formed with a recessed engagement surface 32 constituting a part of a spherical surface, and this engagement surface 32 and the engagement surface 22 of the hook flange 21 are connected to each other when the union nut 28 is screwed into the nipple 11. , to seal between them by pressure contact. The aforementioned nipple 11, union sleeve 19, union nut 25, and union nut 28 collectively constitute a first joint 33, and the compressed air intake port 10 and the front end of the compressed air hose 18 are connected via this first joint 33. is connected to.

Again, in FIG. 1, 34 is a piston type air compressor, and this air compressor 34 and cooler 3
5 is connected by a conduit 36. 37
is an air tank made of a conductive material, and a pipe line 38 is connected between this air tank 37 and the cooler 35.
connected by. Reference numeral 39 denotes an air transformer made of a conductive material, and this air transformer 39 and the air tank 37 are connected by a conduit 40 made of a conductive material. The aforementioned air compressor 34, cooler 35, and air tank 3
7. The air transformer 39, the pipe line 36, and the pipe lines 38 and 40 constitute a compressed air source 41 as a whole. The air transformer 39 has a compressed air outlet (not shown), and a second joint 42 is connected to this compressed air outlet. This second joint 4
Similar to the first joint 33, the joint 2 is composed of a nipple, a union sleeve, and two union nuts, and these nipples, the union sleeve, and the two union nuts are all made of a conductive material. This second joint 42 has a first joint 3
3, the rear end of the compressed air hose 18 is connected. As a result, the rear end portion of the compressed air hose 18 is connected to the compressed air outlet via the second joint 42. The rear end portion 15 of the metal wire 13 of the compressed air hose 18 is connected to the second
It is electrically connected to the joint 42. 43 is a ground wire, one end of which is connected to the outer wall of the air tank 37, and the other end is buried in the ground. As a result, the second joint 42 is grounded via the air transformer 39, the pipe line 40, the air tank 37, and the ground wire 43.

Next, the operation of one embodiment of the present invention will be explained.

First, the air sucked into the air compressor 34 is
After being compressed to a pressure of about 6 kg/cm ² , it flows into a cooler 35 via a pipe 36, where it is cooled to about room temperature. This air then flows into the air tank 37 via the conduit 38 and is temporarily stored, thereby eliminating the pulsation. Next, this air is transferred to pipe 4
After passing through the air, the air flows into the air transformer 39, where it is dedusted, the pressure is adjusted to a predetermined pressure, and the air is sent to the compressed air outlet. Thereafter, the air is transferred to the second joint 42, the compressed air hose 18, and the first joint 3.
3. The air passes through the air passage 9 and is injected from the air injection nozzle, and at the same time sucks up the paint in the paint container 4 through the nipple 3 and ejects it in the form of a mist from the paint injection nozzle. Due to this compressed air and paint jet, the air and paint are charged with negative static electricity, and the air spray gun 1 is charged with positive static electricity. The static electricity charged in the air spray gun 1 is transmitted through the charged part 6, the first joint 33, the metal wire 13, the second joint 42, the air transformer 39, the conduit 40, the air tank 37, and the ground wire 43, and is discharged to the ground. be done. As a result, the charged portion 6 of the air spray gun 1 is always at the same potential as the ground, and no spark discharge occurs.

In addition, in this embodiment, the first joint 33 and the second joint 42 are provided with a threaded portion 24 and a threaded hole 26 that engage with the inner circumferential surface and outer circumferential surface of the compressed air hose 18, and these are threaded in the same thread direction. Furthermore, both ends of the metal wire 13 are connected to the front and rear end surfaces 1 of the hose 18.
6 and 17, the hose 18 is guided smoothly from the inside and outside when the compressed air hose 18 is engaged with the threaded portion 24 and threaded hole 26 of the first joint 33 and the second joint 42, respectively. be done. Therefore, it is possible to prevent the hose from twisting, and to press the metal wire 13 against the joints 33, 42 with sufficient force in a good posture. Therefore, the compressed air hose 18 is connected to the joint 3.
3 and 42, the metal wire 13 is surely pressed into contact with the conductive joints 33 and 42, and desired electrical continuity is obtained. As a result, metal wire 1 and joint 3
3, 42 can be made extremely simple, and the hose 18 can be connected to the joints 33, 4.
A reliable electrically conductive connection can be made by a simple connection operation of simply screwing the connector into the connector 2.

(Effects) As explained above, according to the present invention, it is possible to prevent the inner or outer circumferential surface of the hose from being twisted due to friction or the end surface of the hose from being inclined with respect to the first and second joints, and The front and rear ends of the electrically conductive material can be reliably brought into pressure contact with the first and second joints, and the electrically conductive connection structure of the hand-held air tool device can be made extremely simple, and the connection work can be made extremely easy. .

[Brief explanation of drawings]

FIG. 1 is a schematic overall view showing one embodiment of the present invention, FIG. 2 is a partially cutaway side view showing the grip of the air spray gun, FIG. 3 is a partially cutaway side view of the compressed air hose, FIG. 4 is a partially cutaway side view of the vicinity of the first joint. 1... Air spray gun (hand-held air tool), 6
...Charged part, 10...Compressed air intake, 13...
... Metal wire (metal conductive material), 18 ... Compressed air hose, 24 ... Threaded part (inner peripheral surface engaging part), 26
...screw hole (outer circumferential surface engaging part), 33...first joint,
41... Compressed air source, 42... Second joint, 43...
…ground wire.

Claims (1)

[Claims] 1. A hand-held air tool equipped with a charged part and a compressed air intake electrically connected to the charged part, a compressed air hose whose front end is connected to the compressed air intake via a first joint, a compressed air source having a compressed air outlet connected to the rear end of the hose via a second joint and further electrically grounded by a ground wire conducted to the second joint; wherein the hose is made of synthetic resin, a metal conductive material is buried along the entire length of the hose, and the front and rear ends of the metal conductive material protrude from the front and rear end surfaces of the hose; The first and second joints are conductive joints, and each of the first and second joints has an inner circumferential surface engaging portion and an outer circumferential surface engaging portion that engage with the inner circumferential surface and the outer circumferential surface of the compressed air hose. a joint part is provided, threads in the same thread direction are carved in both engaging parts, and the hose is screwed and fixed to the inner circumferential surface engaging part and the outer circumferential surface engaging part of the first and second joints, respectively. A hand-held pneumatic tool device, characterized in that the front end and the rear end of the metal conductive material are pressed into contact with a first joint and a second joint, so that both joints are electrically connected.