JPH0446713B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of an impact tool used for operations such as drilling or crushing concrete, and is capable of stopping and adjusting the impact for impact. This invention relates to an impact tool that is easy to work with and has sufficient durability.

[Conventional technology and problems] Impact tools conventionally used for drilling in concrete and stone strike the bit in the axial direction while rotating the bit. He stopped hitting and switched to rotation only.

In order to stop the impact, the bit rotation transmission mechanism and the impact transmission mechanism are configured separately, and a clutch is provided to stop the impact transmission mechanism.

Such a clutch must be constructed with gears and a shaft, which not only complicates the mechanism but also increases its external size and weight.

In addition, when changing gears, while driving,
There was a problem that smooth switching was not possible, and when operated while driving, problems such as gear breakage occurred.

For this reason, attempts have been made to stop the impact by stopping the compression action of the piston, but this has not been structurally easy due to the nature of impact tools.

In other words, the number of strikes reaches 3,000 times per minute, the reciprocating distance of the piston is short, and the compressive force is large despite the small internal capacity, making it unreliable even with a simple configuration. It had

In the methods tried in the past, the method of changing the operating position of the piston or bit allows easy and reliable adjustment of the impact force, but it is structurally disadvantageous and has caused problems in terms of reliability and durability.

In addition, in the method of providing a vent in the part of the cylinder that produces compression and opening and closing it with a valve, an attempt has been made to form a flat surface on the outer circumferential side of the vent of the cylinder and form a rubbing valve with the end surface of the eccentric shaft. However, it had the problem that it would lose its effectiveness if the closing force of the friction was weakened.

Furthermore, as in the impact stop device for a drill described in Japanese Utility Model Publication No. 54-168682, a vent is formed at the compression action position of the piston, and this vent is opened and closed by a sliding member that slides along the cylinder. However, even in this case, the sliding member had to be equipped with parts such as an O-ring in order to improve the sealing performance when the vent was closed, and the structure could not be called simple.

In addition, by increasing the diameter of the vent, the effect of stopping the impact is sufficient, but if a vent with a large diameter is formed in the cylinder, the sliding parts of the piston and striker are likely to be worn by the edges of the vent.
Moreover, this was a factor in the loss of lubricating oil inside the cylinder.

Also, due to the nature of the rubbing valve, it is an impact tool.
The operation could become unstable due to severe impact, so it was necessary to make it structurally strong.

However, making the structure more sturdy generally increases the weight and tends to increase the external size, which not only makes it undesirable for tools that are portable or portable. However, this method had problems such as deteriorating workability.

The present invention solves such problems,
The purpose is to create a structure that allows smooth switching between impact and rotation without compromising portability and workability.

[Means for Solving the Problems] The present invention provides a valve seat member in which a plurality of small holes are formed on the outer periphery of a cylinder to form a vent, and the vent is covered and communicated with the vent via a circumferential groove. The problem is solved by providing a valve seat on the outer periphery of the cylinder, a valve seat formed on the outer periphery of the valve seat member, and a press valve capable of pressing the valve seat.

[Operation] When the pressure valve separates from the valve seat and opens the valve seat, the vent formed in the cylinder is opened through the circumferential groove of the valve seat member, so that the piston no longer compresses.

When the pressure valve is pressed against the valve seat, the valve seat is closed and the vent is closed, and the compression action of the piston acts on the striker to produce a striking action.

Furthermore, since the vent formed in the cylinder is composed of multiple small holes, sufficient exhaust capacity is obtained and the cross-sectional area is small, so there is less damage to the O-ring provided in the piston, and durability is improved. You will be better at it.

[Example] The present invention will be described based on an example shown in the drawings. Fig. 1 is a vertical cross-sectional view of a main part of an impact tool according to an example of the present invention, and Fig. FIG. 3 is a side view showing the external appearance.

In FIG. 1, the impact tool is provided with a bit 2 facing inside a cylinder 1, and a striker 4 that reciprocates within the cylinder 1 so as to strike an end 3 of the bit 2.

A piston 5 whose contact portion with the cylinder 1 is sealed with a sealing member such as an O-ring so that the striker 4 is operated by air compression and negative pressure.
are provided.

Also, the piston 5 is moved every minute by the crank 6.
It is configured to perform reciprocating motions at a high speed of about 3000 times.

Furthermore, a plurality of small vent holes 7 are provided in the circumferential direction of the cylinder 1 at a portion of the cylinder 1 where compression between the striker 4 and the piston 5 and negative pressure occur.

This vent 7 is covered by a valve seat member formed along the outer periphery of the cylinder 1, and a groove 9 is formed in the portion of the valve seat member 8 that contacts the vent 7. The vents 7 communicate with each other.

The vent hole 7 has a small cross-sectional area, that is, a small hole, so as not to damage the sealing O-ring of the piston 5 and the like.

A pin-shaped valve seat 10 is formed in a part of the groove 9, and the valve seat 10 is pressed against the valve seat 10.
A pressure valve 11 is provided which is configured to close the opening of.

The pressure valve 11 is configured to be rotated from the outside by an operating knob 13 that is rotatably provided on the frame 12 of the main body, and the tapered portion 14 is actuated by the rotation. The pressure valve 11 is moved in the axial direction to open and close the valve seat 10.

That is, the pressure valve 11 has a tapered portion 14 that is configured of tapered portions that face each other and abut each other.
It is of a push type in which rotational motion is converted into reciprocating motion in the axial direction, and is configured such that the amount of rotation of the knob 13 and the amount of movement of the pressure valve 11 in the axial direction are determined by the amount of taper.

The pressing of the valve seat 10 by the pressing valve 11 is not limited to a structure such as the tapered part 14 as in this embodiment, and various existing structures can be used as long as the pressing valve 11 can be pressed against the valve seat 10. technology can be used.

In FIG. 2, the impact tool has an internally built electric motor and is provided with a handle 15.
The handle 15 is gripped and used for work such as drilling concrete.

In such a configuration, the impact tool has the pressure valve 1
1 presses the valve seat 10 to close the opening of the valve seat 10, the vent 7 of the cylinder 1 is closed, and the reciprocating movement of the piston 5 causes the striker 4 to operate.

Then, due to the operation of striker 4, bit 2
It is possible to drill holes in concrete etc. with Bit 2.

Furthermore, when stopping the impact of the bit 2, by rotating the knob 8 and operating the pressure valve 11 to move away from the valve seat 10, the closing of the valve seat 10 is released, and the compression action of the inside of the cylinder 1 by the piston 5 is released. It disappears, and the striker 4 becomes inoperable.

In this state, the bit 2 only rotates without being struck, and can be used to drill holes in materials other than concrete that do not require striking.

Furthermore, when the piston 5 reciprocates inside the cylinder 1 at high speed, the diameter of the vent hole 7 is small;
A sliding member such as an O-ring disposed around the outer periphery of the piston 5 is less likely to enter the vent 7, thereby reducing damage to the sliding member and improving durability.

Furthermore, even if the lubricating oil sealed in the cylinder 1 is discharged to the outside of the cylinder 1 from the vent 7, the valve seat member 8 covers the outer periphery of the vent 7, so that the lubricating oil etc. Leakage to the outside of 1 is reduced, and durability is improved.

[Effects of the Invention] According to the present invention, a vent consisting of a small hole is formed in the cylinder and is covered with a valve seat member, and a valve seat is formed in this and the opening/closing operation is performed with a press-type pressure valve. Operation can be expected, there is less loss of lubricating oil inside the cylinder, and by arranging multiple vents in the circumferential direction of the cylinder, the vents can be made smaller, reducing wear on the piston's sliding members. Moreover, by providing a valve seat member that communicates with the vent, the valve seat can be configured separately from the cylinder, which facilitates the configuration and improves reliability with a simple structure. It has the effect that it can do.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an impact tool according to an embodiment of the present invention, and FIG. 2 is a side view showing its appearance. 1... Cylinder, 2... Bit, 4... Striker, 5... Piston, 7... Vent, 8... Valve seat member, 9... Groove, 10... Valve seat, 11... Pressure valve , 14... Taper part.

Claims (1)

[Claims] 1 A striker that strikes bits is placed in a cylinder and is operated by a piston, a vent is provided in the area where air compression is effected by the striker and piston of this cylinder, and the strike is adjusted by opening and closing this vent. In the impact tool, a plurality of small holes are formed on the outer periphery of the cylinder to serve as the vent, and a valve seat member is provided on the outer periphery of the cylinder to cover the vent and communicate with the vent through a circumferential groove. An impact tool comprising: a valve seat formed on the outer periphery of a seat member; and a pressure valve capable of pressing the valve seat.