JPS59113381A - Safety device for pneumatic tool - Google Patents

Abstract

PURPOSE:To prevent an accident, by providing a valve guide between a connecting metal and an air hose, providing a main supply passage in the valve guide, and using a spring to push a valve in such a direction as to shut off the main supply passage and fit the valve on the guide. CONSTITUTION:A safety device 1, which comprises a body 2 and a valve guide 4 provided with a main supply passage 4a and fitted with a valve 3 pushed by a spring 5 in such a direction as to shut off the main supply passage, is provided between an air hose and a connecting metal which is to be coupled to a pneumatic tool, so that even if a valve at hand is open and compressed air is supplied, the air pressure upstream to the valve does not rise, said valve 3 does not operate, the main supply passage 4a remains shut off and the pneumatic tool is not started. An accident due to abrupt starting is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatic tool safety device for compressed air such as grinders, sanders, drills, etc.

2. Description of the Related Art Conventionally, a pneumatic tool that performs a predetermined work by starting an air motor using compressed air has been constructed as shown in FIGS. 1 and 2. That is, for example, an air tool 01 such as a compressed air glider is equipped with an air motor 02 inside.
The air motor 02 is started by turning the hand valve 03 ON and OFF to rotate the grinding wheel 04. The compressed air for starting the air motor 02 is supplied from the air tank 06 stored by the air compressor 05. The air is supplied through an air hose 07, and connected to the air tool 01 through a connecting fitting 08 (note that 09 is an exhaust port). However, with the conventional air tool 01, if compressed air is supplied with the hand valve 03 open due to carelessness or the like, or if the supply of compressed air is temporarily interrupted for some reason while the air tool 01 is in use, If the user forgets to close the hand valve 03 and the supply of compressed air is restored, the air tool O1 will start at the same time as the supply of compressed air.

Therefore, it is dangerous to suddenly start the tool before the operator is ready, and most pneumatic tools 01 are equipped with a cutter stop.
There was a problem that this could lead to personal accidents.

The present invention has been proposed in view of the above circumstances, and it is possible for a tool that uses compressed air to forget to close the hand valve after the supply of compressed air is cut off for some reason other than the operation of the hand valve. The object of the present invention is to provide a pneumatic tool safety device that prevents the tool from starting even if the tool is returned to its original position. A cylinder and a valve stop are formed inside the main body, the other end of which is provided with a compressed air outlet that communicates with the air tool, a valve guide installed along the axis, and a valve that slides along the cylinder and the valve guide. and a spring etc. are assembled.

Hereinafter, the pneumatic tool safety device according to the present invention will be explained in detail based on the embodiments shown in FIGS. 3 to 8.

FIG. 3 is a schematic diagram showing the assembled state of the pneumatic tool safety device 10 according to the present invention, in which the safety device l is installed between the connecting fitting 08 connected to the pneumatic tool and the air hose 07. . FIG. 4 is a sectional view showing the assembled state of the safety device 1. Inside the main body 2, a valve 3 is connected to a valve guide 4 and a main body 2.
The main supply passage 4a formed in the valve guide 4 is pressed by a spring 5 at a constant pressure in a direction that roughly cuts off the main supply passage 4a formed in the valve guide 4. The main body 2 is provided with a threaded portion in which a compressed air outlet 2b is formed at one end to which a connecting fitting (not shown) is fixed, and the other end is fixed by a valve guide 4 and a screw 6. The valve guide 4 has a compressed air passage 4b inside.
A nipple is provided, into which an air hose (not shown) is fitted.

In addition, the valve guide 4 and the valve 3, and the cylinder 2a of the main body 2 and the valve 3
In order to maintain airtightness on the sliding surface with
is embedded.

5(a) and 5(b) are a cross-sectional view and an X arrow view showing the details of the main body 2. Inside the main body 2, a cylinder/2a and a valve stop 2c are formed, and an air is communicated with the atmosphere. A pullout hole 2d and a screw hole 2e fixed to the valve guide 4 (not shown) are formed. Note that in this embodiment, the compressed air outlet 2b
A threaded portion 2f and a hexagonal portion 2g for a square cutter are formed in the screw portion 2, to which an air tool connection fitting 08 (not shown) is fixed.

FIGS. 6(a) and 6(b) are cross-sectional views and X arrow views showing details of the valve guide 4, in which main supply passages 4a for compressed air are provided radially on the valve stop 2c side of the main body 2; It communicates with a compressed air passage 4b formed inside. In addition, a small-diameter sub-supply R4c is provided at the tip of the valve guide 4, penetrating along the center line.
is formed, and an annular sub-supply passage 4d is formed in a gap between the valve guide 4 and the circumferential surface of the valve 30 which is slidably fitted in the valve guide 4 (see FIG. 4).

Furthermore, the valve guide 4 has a spigot 4 for connecting with the main body 2.
e, a threaded portion 4f to which the fixing screw 6 is tightened, a spring receiver 4g, and a valve stop 4h are formed.

7(a) and 7(b) are a sectional view and a 2-arrow view showing the details of the valve 3, showing the inner part El 3a that fits on the outer periphery of the valve guide 4 (not shown) and the inner part El 3a of the main body 2. An outer 143b and a four-way socket 3c that fit into the cylinder 2a (not shown) are formed, and both the inner periphery 3a and the outer periphery 3b have an armpit groove 3c.
, 3d are formed, and airtight O-rings 7 and 8 are fitted therein.

In order to operate the safety device 1 configured as described above, the valve 3 is first moved by the spring 5 as shown in FIG. 8(a), which shows the state before compressed air is supplied. Since the main compressed air supply path 4a is in the restored state after being pressed by the compressed air, the compressed air main supply path 4a is blocked. Therefore, when compressed air is supplied with the hand valve 03 open, the compressed air passes through the sub supply path 4c or 4d and reaches the air motor 02 of the air tool 01, but the pressure at the compressed air outlet 2b does not rise, and the compressed air is discharged to the atmosphere through the exhaust port 09 while the valve 3 is pressed by the spring 5 and returned to its original position. Therefore, the compressed air supplied to the air tool 1 is supplied in small amounts from the sub-supply paths 4c and 4d, and the 6D air motor 02 is not activated.

When the hand valve 03 is closed, the compressed air passing through the sub-supply path 4C or 4d is not released to the atmosphere, and the pressure at the compressed air outlet 2b rapidly increases, as shown in FIG. 8(b). 3
slides against the spring 5 and opens the main supply path 4a, making it possible to start and stop a predetermined pneumatic tool 01. If you turn on the hand valve 03, the air tool 01 will start, and the
When set to FF, it stops. Once activated, the valve 3 remains in that state until the pressure at the compressed air outlet 2b disappears.

On the other hand, if the supply of compressed air is cut off for some reason other than the hand valve 03, the pressure in the compressed air passage 4b and the pressure at the compressed air outlet 2b decrease, and the valve 3 is reset by the spring 5. , cut off the main supply path 4a (Fig. 8(C)
). When the compressed air supply source is restored in this state, the hand valve 03 is open, and a small amount of compressed air passing through the sub supply path 40 or 4d is discharged to the atmosphere through the air motor o2 and the exhaust port 09. However, the air pressure at the compressed air outlet 2b does not increase.

Therefore, the valve 3 maintains its returned state, and the main supply path 4ai
If the ignition remains disconnected, the air tool 01 will not start. Once the hand valve 03 is closed, the air pressure at the compressed air outlet 2b increases, and the valve 3 slides against the spring 5, returning to a state where normal starting and stopping are possible.

As described above in detail based on the embodiment shown in the drawings, according to the pneumatic tool safety device according to the present invention, a small amount of compressed air is supplied to the air passage, and the air pressure in front of the hand valve is Utilizing the principle that when opened, there is almost no change in pressure, and when closed, the pressure rises to the supply pressure, the air pressure slides the valve inside the device, opening the main supply path for compressed air. In a pneumatic tool equipped with this device, when the hand valve is open, the air pressure in front of the hand valve does not increase even if compressed air is supplied, so the device does not operate. Therefore, the main supply path remains blocked and the pneumatic tool does not start, thereby preventing accidents caused by sudden start-up. Furthermore, once the hand valve is closed, the air pressure in front of the hand valve increases, and the device is activated to open the main supply path for compressed air, making it possible to start and stop as specified.

Furthermore, the safety device according to the present invention has a simple structure and can be miniaturized, and after installing the device, when using the pneumatic tool, it is possible to use it in the same way as before without causing any discomfort. In addition, no power source other than compressed air is required, and there is little loss when compressed air passes through the device. In addition, the sub-supply channel of this device has a structure that prevents clogging with dirt, etc., but even if dirt does become clogged, it can be forcibly discharged by opening the main supply channel. be.

Furthermore, the safety device according to the present invention can be used for all types of pneumatic tools, and the mounting position can be selected as appropriate for pneumatic tools, air hoses, etc.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional compressed air grinder; Figure 2
The figures are a schematic diagram showing the connection fittings in Figure 1, Figure 3 is a schematic diagram showing the state of assembly of the pneumatic tool safety device according to the present invention,
The figure is a cross-sectional view showing the assembled state of the safety device according to the present invention, FIGS. 7(a) (b) are sectional views and 2-arrow views showing details of the valve, and FIGS. 8(a) (b) are sectional views showing details of the valve guide and views taken along the Y arrow.
) (c) is an explanatory diagram showing the order of operation of the safety device according to the present invention. 01...Air tool, 02...Air motor, 03...Hand valve, 07...Air hose, 08...Connection fittings, 1...Safety device, 2...Main body. 2a... Cylinder, 2b... Compressed air outlet, 3... Valve, 4... Valve guide, 4a... Main supply path, 4b... Sub supply path, 5... Spring. Patent Applicant: Mitsubishi Heavy Industries, Ltd. Sub-Agent Patent Attorney: Shibu Mitsuishi (and 1 other person) Figure 6 (0) (
b) 4/ Figure 7 (') (b) Figure 8 (Q) (t) 1 Procedural amendment April 1982! Mr. Otousu, Commissioner of the Patent Office 1, Indication of the case 1982 Patent Application No. 222487, Showa Year Trial No. 2, Name of the invention Pneumatic tool safety device 3, Relationship with the case of the person doing the Mi correction Patent applicant Tokyo 2-5-1 Marunouchi, Chiyoda-ku, Tokyo (620) Mitsubishi Heavy Industries, Ltd. 4, Sub-Agent Postal Code 107 6, "Detailed description of the invention" [Brief description of drawings] column of the specification subject to amendment and Drawing 7, contents of amendment (1) In the 9th line of page 6 of the specification, [Packing grooves 3c, 3dJ] are corrected as [Packing grooves 3d, 3eJ. (2) On the 5th line of page 11, the statement ``4b...-sub supply path'' is corrected to ``2r4b, 4c...sub supply path''. (3) Correct the number in Figure 7 (a) of the drawing to match the red gate. ? , Attachment 10 list of necks

Claims (1)

[Claims] A hand valve for starting and stopping the air motor, a valve guide having a compressed air inlet that is fixed to the air hose between the air tool and the air nurse, and a valve guide that is fixed to the air tool and forms a cylinder inside. A main body having a compressed air outlet, a valve slidably mounted between the valve guide and a cylinder inside the main body, a spring that presses the valve to a valve stop side in the cylinder at a constant pressure, and the valve. A main supply path for compressed air formed radially on the valve stop side of the guide, and a main supply path of the valve guide formed in a gap between the tip or the circumferential surface of the valve guide and the valve are pressed by a spring. 1. A pneumatic tool safety device comprising: a sub supply path having an opening area large enough to prevent an air motor from rotating when the air motor is shut off by a valve.