JPH0549863B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention enables output adjustment by adjusting the flow rate of pressure fluid, and further enables automatic closing using the pressure of this fluid. Regarding a hand grinder using a valve.

[Conventional technology]

Tools such as grinders must be easy to operate and must be operated in a safe manner, and if a fluid motor is used for such tools, the opening of the valve that changes the flow rate of the pressure fluid must be controlled. By adjusting it, you can easily change the output of the tool, and when stopping the tool,
It is necessary to be able to close the valve quickly.

[Problem to be solved by the invention]

Particularly in the case of hand tools such as hand grinders, it is necessary for the worker to be able to easily adjust the output while holding the hand tool, and to prevent damage to at least one of the tool and the workpiece. It must be possible to stop the machine very easily in order to prevent accidents such as accidents or injury to workers.

Conventional valves for regulating the flow rate of fluid, for example, as proposed in Japanese Utility Model Application Publication No. 52-103434, have a valve seat formed inside the valve body, and a lore portion that is screwed into the valve body. Some valves have a valve rod protruding from the center of the inside of the operating section, and a valve body that comes into contact with the valve seat is provided at the tip of the valve rod.

This type of valve has a screw between the operating part and the valve body to rotate the operating part and adjust the opening degree of the valve. When the valve is released, the opening degree of the valve is maintained as it is.

However, when using this type of valve as a valve to adjust the flow rate of pressurized fluid that operates a hand tool such as a hand grinder, the operator must adjust the opening degree of the valve while holding the hand tool. It is not easy to use such valves for hand tools such as hand grinders, and it is dangerous because the tool will continue to operate even if the operator takes his hand off the hand tool. It was extremely inappropriate not only from the standpoint of safety but also from the standpoint of safety.

In addition, when using a large and heavy hand tool, in order to securely grip it in a raised position, the flow rate of the pressure fluid is controlled by adjusting the opening of the valve while the hand tool is in use. The problem was that it was difficult to This means that if you need to adjust the output of a hand tool while it is in use, you can move the hand tool away from the workpiece and position the tool's output at a position where there is no risk of damaging the workpiece. This means that the tool must be adjusted again and brought closer to the workpiece.

In view of the above problems, the present invention is capable of automatically closing the valve using the pressure of a pressurized fluid, and also allows the flow rate of this fluid to be easily adjusted by a method similar to operating the throttle of a motorcycle. By installing an automatic shutoff valve at the end of the handle, it will automatically stop when you remove your hand from the handle.
The object of the present invention is to provide a hand grinder that is safe and whose output can be easily adjusted during operation.

〔composition〕

In order to achieve the above object, the hand grinder according to the present invention has an inlet passage for a pressure fluid that operates a fluid motor formed therein, and an automatic grinder inside the grip on the side of the inlet passage of a handle pipe whose both ends are formed as grips. The automatic shutoff valve includes a cylindrical casing having an open end at one end and a fluid supply port at the other closed end; the automatic shutoff valve is fitted into the casing in a sealed state;
an inner cylinder having a valve seat on the opposite side of the closed end of an annular protrusion formed therein; and a valve having one end fixed to the closed end, passing through the inside of the annular protrusion, and having the other end abutting the valve seat. The casing has a cam that slides in the axial direction when rotated relative to the inner cylinder, and a guide portion that is a pin that engages with the cam. A pressure chamber, which is a closed space, is formed by the casing and the valve body, and when this pressure chamber is pressurized, the casing is moved back by the guide portion, and the valve body is moved against the valve seat. The fluid motor is configured to abut to close the pressure chamber, and is characterized in that the fluid motor is integrally formed with a spindle having a grinding device.

[Effect]

Since the automatic shutoff valve used in the hand grinder of the present invention has the above-mentioned configuration, pressure is generated in the space surrounded by the casing and the inner cylinder slidably fitted inside the casing. When the chamber is pressurized by the pressure fluid, the valve body integrated with the casing comes into contact with a valve seat formed in the inner cylinder, and the pressure chamber can be automatically closed.

In addition, since the inner end area A of the closed end of the casing is formed larger than the cross-sectional area B between the annular projection in the inner cylinder fitted into the casing and the penetrating portion of the valve stem, the casing Unless a force is applied to open the valve, the valve body is pressed against the valve seat by the pressure of the fluid, and the valve can be closed automatically, without the use of any auxiliary elastic member. It can be automatically closed. in this way,
The automatic shutoff valve used in the hand grinder of the present invention is very easy to operate, and can be reliably closed when the operator takes his hand off the grip (hereinafter also referred to as handle). It is something.

Further, since the guide portion is composed of a cam provided on the casing at a certain angle with respect to the axial direction of the casing, and a pin provided on the inner cylinder that engages with the cam, the opening degree of the valve can be adjusted by using the casing. This can be done by a small rotational movement of the fluid, making it extremely easy to adjust the fluid flow rate.

The casing is cylindrical and rotatable, and can be manufactured by simple operations such as boring or rotating, so this automatic shut-off valve is partially inexpensive. It can be manufactured and parts can be easily replaced.

In addition, when using this automatic shutoff valve in a tool, it is preferable to fix the inner cylinder to the handle of the tool, so that the output of the tool can be adjusted without the operator taking his hand off the handle. I can do it.

Therefore, since the hand grinder of the present invention uses the above-mentioned automatic shutoff valve to adjust the output of the fluid motor, the hand grinder can be automatically stopped by releasing the hand from the handle of the hand glider. By rotating this handle and moving the casing in the axial direction, the opening degree of the valve can be adjusted and the output of the tool can be easily controlled. especially,
Even if the hand grinder is accidentally dropped, the tool will automatically stop as soon as it leaves the operator's hands, so there is no risk of damaging the workpiece or injuring the operator. It is possible to prevent such accidents from occurring.

Also, a self-closing valve integrated into the handle forming the gripping part of this hand grinder is such that pressurized fluid is introduced into the rear part of the handle at a supply port provided at the closed end of the casing, for example through a hose, and then this It is introduced into the outlet of the inner cylinder through the valve body of the automatic shutoff valve, and further into the hand grinder through, for example, a pipe. In this method, the handles form part of the hand grinder, so that power control of the tool can be achieved by adjusting the opening of a self-closing valve incorporated in one of the handles.
The opening and closing operations of this valve are performed by movement of the casing in the axial direction.

As described above, according to the present invention, a hand grinder with very easy output adjustment and excellent safety can be obtained. The pressure fluid flows into and out of the fluid motor through the handle pipe of this hand grinder, providing a high degree of safety against breakage. By configuring
The operator can work in close proximity to the hand grinder, which is very easy to handle.

Further, by making the axis of rotation of the spindle substantially parallel to the longitudinal axis of the handle, the user can assume a working posture that facilitates grinding. When using the grinder in a direction such as rotating the handle downward, the grinder can be reliably moved over vertical and similar surfaces.

The spindle is hollow and by incorporating the fluid motor into this spindle, the space between the handles can be used effectively and the fluid motor can be reliably protected from dirt.

Furthermore, it is fixed to the connecting part of the handle pipe,
Since the safety guard is provided to cover at least the operator side of the grinding device, a fence is formed over the entire rear part of the grinder facing the operator, resulting in extremely high safety.

Also, with a grinding machine that incorporates a number of circularly slotted grinding discs fixed coaxially around the spindle of the grinding machine and further fixed by means of a retaining disc, the disc plate becomes very unstable. Even regular workpiece surfaces can be effectively ground. Furthermore, since the slotted disc assembly is simply placed between the retaining discs, it can be easily replaced with a new grinding disc. It should be noted that the entire assembly is simply fixed at the end of the spindle by a screw, and such a grinding disc is described in U.S. Patent Application No.
Disclosed in No. 395001.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the automatic shutoff valve for the hand grinder according to this embodiment has one end of the casing 1 as an open end 1a and the other end as a closed end 1b.
At the same time, a fluid supply port 12 is provided at this closed end 1b.
has been established. Further, the inner cylinder 2 is fitted into the casing 1 in a sealed state, and furthermore, the inner cylinder 2 is fitted into the casing 1 in a sealed state.
An annular projection 2a is formed inside the annular projection 2a, and a valve seat 14 is formed on the opposite side of the annular projection 2a to the closed end 1b.

Further, one end of a valve rod 10 having a valve body 7 which penetrates the inside of the annular projection 2a and comes into contact with the valve seat 14 is fixed to the closed end 1b of the casing 1. Furthermore, the casing 1 has a cam 4 and guide portions 3, 4, each of which is made up of a pin 3 that engages with the cam 4, so as to slide in the axial direction when rotated relative to the inner cylinder 2.

A pressure chamber 11 is formed in a space closed by the casing 1 and the valve body 7, and the inside of this pressure chamber 11 is pressurized by the pressure fluid flowing into the pressure chamber 11. When no force is applied from the outside, the casing 1 retreats along the guide portions 3 and 4, and the valve seat 1
At 4, the valve body 7 is brought into close contact with the valve seat 14 to close the pressure chamber 11.

The outside of the casing 1 of the automatic shutoff valve of this embodiment is covered with rubber 16 to make it easy to hold and to grip firmly. Further, in this embodiment, the valve stem 10 is screwed into the closed end 1b of the casing 1, and the valve stem 10 partially holds the dish-shaped ring portion 7 and partially holds the pipe 8, and the valve stem 10 holds the pipe 8 at a distance.
holds the ring part 7 at a predetermined distance from the end of the casing 1.

Furthermore, as shown in FIG. 3, in the guide section of this embodiment, a penetrating inclined track 4 is formed in the casing 1, and a bolt head 3 is disposed on this track 4, so that the bolt head 3 is disposed in the casing 1. The rotation moves the casing 1 axially relative to the inner cylinder 2.

This inner cylinder 2 is inserted into the casing 1 so as to extend an appropriate distance within the casing 1, has an annular groove 2b at one end, and a sealing member 6 is disposed in this groove, so that the inner cylinder 2 and the casing 1 are It becomes a seal between.

Further, an annular projection 2a is formed on the inside of the inner cylinder 2, and this annular projection 2a forms a valve seat 14 on an outer surface extending perpendicularly to the axis. Furthermore,
A pin 3 for connecting the casing 1 at that position is screwed into this annular projection 2a.

Finally, the outlet 15 of the inner cylinder 2 extends outward.
has a male thread that is screwed into the pipe 5, and pressurized fluid is introduced into the pipe 5 when in operation.

As can be seen from the drawing, the valve incorporates a sealing member 9 in the annular groove 7a formed between the ring 7 and the pipe 8, so that in the position shown in FIG. Pressure fluid can be completely shut off.

By rotating the handle 16 in the direction of the position shown in FIG. This allows pressure fluid to pass through the valve. The fluid passage can be continuously varied from a closed position to a maximum open position, thereby allowing a continuously varying amount of pressure fluid introduced into the motor.

When the handle 16 is released, the inner end area A of the casing 1 is wider than the cross-sectional area B between the annular projection 2a in the inner cylinder 2 fitted into the casing and the penetrating portion of the valve stem 10. , due to the pressure of the fluid, moves the casing to the right, thereby moving the valve body 7, 8, 9 towards the valve seat 14, where it closes the valve. Therefore, the valve can be a self-closing valve without providing an elastic member such as a spring.

This automatically and reliably shuts off the pressure fluid introduced into the fluid motor, thus stopping the fluid motor, making it very safe and highly reliable. In particular, in the event of a fall or other accident, the valve will automatically close, thus stopping the fluid motor.

In summary, this valve, which has a simple structure and excellent reliability, can continuously and variably control the flow rate of pressure fluid, and at the same time ensures full control of tool operation, that is, tool activation/stopping and power adjustment. can be done. Furthermore, when the user stops gripping the handle, the fluid motor can be immediately and reliably stopped.

Next, FIGS. 4 and 5 show a hand grinder according to the present invention. Pressure fluid is supplied to a hose 13 connected to the valve by a supply port 12 of a suitable type.
is introduced into the fluid motor 20 through.

The hand grinder has a handle pipe 17 that is substantially U-shaped. In Figure 5,
The handle pipe 17 is the grip (handle) 2
5 and 26 are bent so as to be closer to the user than the center of the hand grinder. this is,
It makes it very easy for the operator to use the tool. Handle pipe 1 of this hand grinder
7 has handles 25 and 26, and the handle pipe 17 further has an inlet passage 18 and an outlet passage 19 therein. In this case, the handle pipe is assembled by two pipes, and the inlet passage 18 and the outlet passage 19 are connected.

The above-mentioned automatic shutoff valve 21 is arranged on the handle 25. This valve has an inlet nozzle 22 suitably having a snap feature for connection to a pressure hose. In the handle 26 the outlet passage 19 is connected to the outlet opening 2
It ends at 3. This outlet opening 23 can be provided with a filter 24 or a sound absorber, and again can be connected to a hydraulic return hose.

A fluid motor 20 is disposed within a hollow spindle 27 with the inlet passage 18 and the outlet passage 19 connected. This machine is suitably driven by compressed air, but hydraulic machines could also be used.

The fluid motor 20 is controlled by a valve 21;
The fluid motor 20 rotates the spindle 27. A number of grinding discs 28 are attached to the holding disc 3
1 to the spindle. These grinding discs are made of sandpaper or abrasive cloth in this example, but other materials can also be used. The disk 28 is formed with slots made of a number of metal plates.
These sheets can be constructed double so that both sides can be ground.

However, other types of grinding equipment can also be used. The spindle can be coated with hair or the like to polish the object.

When the polishing device shown in the drawing rotates,
Very irregular or difficult workpieces can be ground evenly. This is because the sheet metal can penetrate into very deep shapes and can be ground efficiently. This means that the hand grinder according to the invention becomes very effective for the intermediate grinding of polished workpieces, such as furniture, for example.

Furthermore, the hand grinder has a safety guard 30. It is dome-shaped to surround the part of the grinding device that faces the user. Safety guard 30 may be suitably made of a light and durable plastic material. The safety guard can be made into a number of other shapes, such as semi-circular or quadrilateral.

Moreover, the handle pipe 17 can also be made of aluminum. It is important to reduce the weight of the grinder to avoid user fatigue. The grinder can be made extremely lightweight by having a compact construction and using as light and light a material as possible.

The grinding disc 28 is fixed to the spindle 27 between the holding discs 31. These are removable flanges 33 by means of a center screw 29.
and the fixed flange 32 under tension. When the grinding discs 28 become worn, they can be replaced. The holding disk 31 has a central opening into which the spindle 27 fits. This is for example provided with longitudinal teeth in order to hold the grinding disc 28 tightly and tautly between the holding discs 31 or by other fastening means.

Note that the present invention is not limited to the embodiments shown in the drawings. The hand grinder according to the embodiment described above could be made in many other different ways within the scope of the invention.

〔Effect of the invention〕

The hand grinder of the present invention has an inlet passage for pressurized fluid for operating a fluid motor formed therein, and has an automatic shutoff valve inside the grip on the side of the inlet passage of a handle pipe whose both ends are formed as grips. This automatic shutoff valve includes a cylindrical casing having an open end at one end and a fluid supply port at the other closed end, and the closed end of an annular protrusion that is fitted into the casing in a sealed state and formed inside. and a valve stem having one end fixed to the closed end, passing through the inside of the annular projection, and having a valve body abutting the valve seat at the other end, The casing has a cam that slides in the axial direction when rotated relative to the inner cylinder, and a guide section that is made up of a pin that engages with the cam, and further has a guide section that is closed by the casing and the valve body. A pressure chamber is formed in the space, and when the pressure chamber is pressurized, the casing is moved back by the guide portion to bring the valve body into contact with the valve seat and close the pressure chamber. It is composed of
The present invention is characterized in that the motor is integrally formed with a spindle having a grinding device.

Therefore, when the pressure chamber formed in the space surrounded by the casing and the inner cylinder slidably fitted inside the casing is pressurized by the pressure fluid,
A valve body integrated with the casing can come into contact with a valve seat formed in the inner cylinder to automatically close the pressure chamber.

In this way, since the above-mentioned automatic shutoff valve is used to adjust the output of the fluid motor, the hand grinder can be automatically stopped by releasing the grip of the hand grinder. By rotating the grip and moving the casing in the axial direction,
The output of the tool can be easily controlled by adjusting the opening degree of the valve. In particular, even if you accidentally drop the hand grinder, the tool will automatically stop as soon as it leaves the operator's hands, so there is no risk of damaging the workpiece or injuring yourself. It is possible to prevent accidents that may occur.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the automatic shut-off valve in the closed state along the - line shown in FIG. 3, and FIG. 2 is a cross-sectional view of the same automatic shut-off valve in the open state.
Fig. 3 is a front view of the automatic shutoff valve, Fig. 4 is a sectional view of the hand grinder taken in the direction of the arrow shown in Fig. 5, and Fig. 5 is a plan view of the hand grinder shown in Fig. 4. It is a diagram. 1... Casing, 1a... Open end, 1b...
Closed end, 2... Inner cylinder, 2a... Annular projection, 2b...
...Annular groove, 3...Pin, 4...Cam, 6...Seal member, 7...Valve body, 7a...Annular groove, 8...Pipe, 9...Seal member, 10...Valve stem, 10a
... Head, 11 ... Pressure chamber, 12 ... Supply port, 1
4... Valve seat, 17... Handle pipe, 18...
Inlet passage, 19...Outlet passage, 20...Fluid motor, 25...Grip, 26...Grip, 2
7...Spindle, 28...Grinding device, 30...
Safety guard, 31...holding disk.

Claims (1)

[Claims] 1. An inlet passage 18 for pressurized fluid that operates the fluid motor 20 is formed inside, and both ends are connected to grips 2.
An automatic shutoff valve is provided inside the grip 25 on the inlet passage 18 side of the handle pipe 17 formed as 5 and 26, and this automatic shutoff valve has an open end 1a at one end and a closed end 1b at the other end. A cylindrical casing 1 having a fluid supply port 12, and an annular projection 2a that is fitted into the casing 1 in a sealed state and formed inside.
an inner cylinder 2 having a valve seat 14 on the side opposite to the closed end 1b; one end fixed to the closed end 1b, passing through the inside of the annular protrusion 2a, and the other end having the valve seat 14 fixed to the closed end 1b;
The casing 1 consists of a cam 4 and a pin 3 that engages with the cam 4 so as to slide in the axial direction when the casing 1 rotates relative to the inner cylinder 2. Furthermore, a pressure chamber 11 is formed in a space closed by the casing 1 and the valve body 7, and when the inside of this pressure chamber 11 is pressurized, the guide portion Accordingly, the casing 1 is configured to move backward and bring the valve body 7 into contact with the valve seat 14 to close the pressure chamber 11, and the fluid motor 20 is connected to a spindle 27 having a grinding device 28. A hand glider characterized by being formed in one piece. 2 The inner end area A of the closed end 1b of the casing 1 is
Cross-sectional area B between the annular projection 2a in the inner cylinder 2 fitted into the casing 1 and the penetrating portion of the valve stem 10
Claim 1 characterized in that it is broader than
Hand grinder as described in section. 3. The guide portion is characterized by comprising a cam 4 provided on the casing 1 at a certain angle with respect to the axial direction of the casing 1, and a pin 3 provided on the inner cylinder 2 that engages with the cam 4. A hand grinder according to claim 1 or 2. 4 a pipe 8 provided coaxially around the outer periphery of the valve stem 10;
A sealing member 9 is inserted into an annular groove 7a formed by an annular valve body 7 having an L-shaped cross section, which is held between the pipe 8 and the head 10a of the valve stem 10 and coaxially provided on the outer periphery of the valve stem 10. into the valve seat 14 and the valve body 7.
The hand grinder according to any one of claims 1 to 3, characterized in that the surface that comes into contact with is sealed. 5 An annular groove 2b is provided on the outer circumferential surface of the inner cylinder 2 that slides on the casing 1, and a sealing member 6 is provided in this annular groove 2b.
The hand grinder according to any one of claims 1 to 4, characterized in that the casing 1 and the inner cylinder 2 are sealed by fitting the casing 1 and the inner cylinder 2. 6 The axis of rotation of the spindle 27 is the grip 25,
Hand grinder according to any one of claims 1 to 5, characterized in that the hand grinder is substantially parallel to the longitudinal axis of 26. 7. The hand grinder according to any one of claims 1 to 6, wherein the spindle 27 is hollow and the fluid motor 20 is incorporated in the spindle 27. 8 Fixed to the connecting part of the handle pipe 17,
The hand grinder according to any one of claims 1 to 7, further comprising a safety guard 30 that covers at least the operator side of the grinding device 28. 9. The grinding device 28 consists of a number of circularly slotted grinding discs fixed coaxially around the spindle 27 and by means of a retaining disc 31.
The hand grinder according to any one of Items 1 to 8.