JPH11254349A - Hammering tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an always stable hammering force by providing a path closed when an intermediate piece is positioned in a hammer side and communicated when the intermediate piece is positioned in a tip tool side. SOLUTION: A pressure in an air chamber 6 fluctuates by the reciprocating movement of a piston, a hammer 7 clashes with an intermediate piece 11, and a hammering force is applied to a tip tool 15. A step 12 having two stage parts is provided in the intermediate piece 11. Thus, in a non-load state where the tip tool 15 and the intermediate piece 11 are moved to frontmost parts, and only when the intermediate piece 11 is moved to a contact part and the hammer 7 is not reciprocated, a path for communicating a hammering mechanism inside with its outside is formed between the intermediate piece 11 and a sealing material 13, in other words, a gap 14 enough for adjusting a pressure in the hammering mechanism part is generated. Thus, since air is supplied from the outside through the gap 14 into the hammering mechanism part by an amount equivalent to an air amount discharged from the inside of the hammering mechanism part to the outside by an increased pressure, the pressure in the hammering mechanism part is set equal to an atmospheric pressure at the end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hitting tool such as an electric hammer having an internal pressure adjusting mechanism.

[0002]

2. Description of the Related Art A striking tool is provided with a reciprocating motion converting mechanism for converting the rotational force of a motor into a striking force. When the tip tool is pressed against a workpiece such as concrete, the tip tool moves toward the meson. The reciprocating motion converting mechanism unit causes the meson struck by the striking element reciprocating in the cylinder via the air chamber to collide with the end of the tool bit, thereby applying a striking force to the tool bit. The above-mentioned meson is held in the retainer sleeve via a sealing material so as to be movable in the axial direction, and furthermore, the impact on the striking tool body generated when the meson collides with the tip tool and moves to the opposite tip tool side is reduced. To this end, a damper and a damper washer as described in Japanese Utility Model Publication No. 4-13108 are provided at the rear end of the retainer sleeve.

[0003] Air and lubricating oil in the striking mechanism are sealed by the seal material.

[0004]

When an operation is performed using the above-mentioned striking tool, the temperature around the striking element reciprocating to strike the meson becomes high. Thereafter, if the operation is interrupted and the impact tool is left unattended, the temperature around the impact element, which was high, also drops to room temperature, and the pressure in the impact mechanism decreases accordingly. However, when the impact tool is used, the temperature in the impact mechanism increases, and the air between the impact element and the meson is compressed by the reciprocating motion of the impact element. As a result, the air in the impact mechanism has a considerably high pressure. Then, air leaks to the tool bit by the striker. Normally, a sealing material is arranged between the meson and the retainer sleeve so that air inside the striking mechanism does not flow out of the striking mechanism. However, the sealing force of the sealing material is limited. Since the air inside the part flows out to the tip tool side, when the operation is completed and the temperature returns to a normal state, the pressure in the impact mechanism becomes a negative pressure as compared with before the use of the impact tool.

[0005] Incidentally, the inside of the striking mechanism after the work is completed has a negative pressure as compared with the outside air pressure, but the state of the negative pressure is maintained by the sealing force of the sealing material described above. Air does not flow into the impact mechanism. Therefore, when the above-mentioned impact tool is used again, since the compression force in the impact mechanism is reduced, the amplitude due to the reciprocation of the impact element becomes small, and the velocity of the impact element at the impact point is small and rebounds. Since the speed is reduced, the amplitude energy of the striker is not amplified, and as a result, there is a problem that the impact force is reduced due to a decrease in pressure. In addition, when the striker returns before reaching the strike point, there is a problem that the strike operation is not performed at all.

[0006] An object of the present invention is to solve the above-mentioned problem and to provide a striking tool capable of obtaining a stable striking force.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide a striking tool comprising a tip tool, a meson which transmits a striking force to the tip tool and is movable by a predetermined amount in an axial direction, and a hammer which strikes the meson. When the meson is located on the striker side, it is closed, and when the meson is located on the tip tool side,
This is achieved by providing a communicating passage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A striking tool having an internal pressure adjusting mechanism according to the present invention will be described with reference to FIGS. FIG.
FIG. 2 is a partially longitudinal side view showing a striking tool according to the present invention, FIG. 2 is a partially omitted longitudinal side view showing a striking state of the striking tool, and FIG. 3 is a partially omitted longitudinal side view showing a non-loaded state of the striking tool. is there.

1 and 2, the driving force of a motor 1 is converted into a reciprocating motion of a piston 3 which slides in a cylinder 4 fitted to a cylinder case 5 via a crankshaft 2. When the tip tool 15 is pressed against a workpiece such as concrete, the striker 7 that slides in the cylinder 4
However, since the breathing hole 8 provided in the cylinder 4 is closed, an air chamber 6 which is substantially closed is formed between the cylinder 4 and the striker 7 and the piston 3. The air chamber 6 is reciprocated by the piston 3
The pressure in the air inside the cylinder fluctuates, and accordingly, the striker 7 slides in the retainer sleeve 10 engaged with the front cover 9 fixed to the cylinder case 5 via a steel ball in the axial direction of the tool bit 15. This impinges on the tip tool 15. The meson 11 is provided with steps having different diameters. In the present embodiment, a step 12 formed by two steps is provided on the meson 11. In addition, an O-ring or the like is provided on the inner periphery of the retainer sleeve 10 for guiding the meson 11 as a seal member 13 that is in close contact with the outer periphery of the meson 11, thereby sealing air and lubricating oil in the striking mechanism. ing. Here, the inside of the impact mechanism is mainly inside the cylinder 4.
The space on the right side of the meson 11 (the space between the seal member 13 and the vicinity of the collision between the meson 11 and the striker 7) communicates with the inside and outside of the cylinder 4 and the space on the left side of the meson 11 (the seal). Material 13, meson 11, and tip tool 1
5) is in communication with the outside air outside the impact tool main body.

When work is performed using the above-mentioned impact tool, heat is generated due to pressure changes in the motor 1, the bearing of the rotary shaft, the sliding portion of the reciprocating motion conversion mechanism, and the air chamber 6, and heat is generated in the impact tool. The temperature rises. In particular, in a small impact tool having a small volume in the impact mechanism, a large pressure rise occurs in the impact mechanism. Due to this pressure rise, the temperature in the impact mechanism rises to about 80 ° C., and the air between the impactor 7 and the meson 11 is compressed by the reciprocating motion of the impactor 7, resulting in the air in the impact mechanism being reduced. When the pressure becomes considerably high, air leaks to the tip tool 15 side due to the striker 7. Normally, a seal member 13 is provided between the meson 11 and the retainer sleeve 10 so that air inside the impact mechanism does not flow out of the impact mechanism, but the sealing force of the seal material 13 has a limit. When the temperature in the impact mechanism is returned to a normal state after the work is completed because the air in the impact mechanism flows out to the tip tool 15 side beyond the pressure, the pressure in the impact mechanism becomes:
The pressure becomes negative compared to before using the impact tool. However, by providing the step 12 on the meson 11 as described above, the meson 11 moves to the abutting portion 10a in a state where the tip tool 15 and the meson 11 have moved forward most, that is, in the no-load state shown in FIG. Only when the striker 7 does not reciprocate, there is a passage between the intermediate element 11 and the seal member 13 for communicating the inside of the strike mechanism with the outside, that is, a gap 14 that can adjust the pressure in the strike mechanism. Occurs. Accordingly, since the air that flows out from the inside of the impact mechanism to the outside due to the pressure increase and the air flows into the impact mechanism from the outside through the gap 14, the pressure in the impact mechanism becomes equal to the atmospheric pressure.

From the above, the impact tool according to the present embodiment cannot perform the impact operation because the impact force of the meson 11 is reduced due to the pressure drop and the impact element returns before reaching the impact point. Without falling into a state,
A stable striking force can always be obtained, and the pressure in the striking mechanism can be adjusted with a simple configuration.

Further, the intermediate element 11 which moves toward the workpiece by lifting the impact tool from the workpiece and releasing the tip tool 15 during the impact operation eventually collides with the abutting portion 10a of the retainer sleeve 10 and strikes. Although it rebounds to the side 4, since the sealing material 13 acts so as to bite into the step 12 provided in the sliding portion of the intermediate piece 11, it is possible to suppress the rebound of the intermediate piece 11, so that unnecessary impact on the tip tool 15 is prevented. It is possible to suppress the phenomenon that occurs, that is, the idling.

[0013]

According to the present invention, when the meson is located on the striker side, the passage is closed, and when the meson is located on the tip tool side, a communication passage is provided, so that a stable strike is always achieved. A powerful impact tool can be provided.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal side view showing a striking tool according to the present invention.

FIG. 2 is a partially omitted longitudinal side view showing a striking state of the striking tool according to the present invention.

FIG. 3 is a partially omitted longitudinal side view showing a no-load state of the impact tool according to the present invention.

[Explanation of symbols]

1 is a motor, 2 is a crankshaft, 3 is a piston, 4
Is a cylinder, 5 is a cylinder case, 6 is an air chamber, 7 is a striker, 8 is a breathing hole, 9 is a front cover, 10 is a retainer sleeve, 11 is a meson, 12 is a step, 13 is a sealing material, 14 is a gap, 15 is a tip tool.

Claims (3)

[Claims] 1. A striking tool comprising: a tip tool; an intermediate member that transmits a striking force to the tip tool and is movable by a predetermined amount in an axial direction; A striking tool, characterized in that the striking tool is closed when it is located on the child side, and has a passage communicating with it when the meson is located on the tip tool side. 2. The striking tool according to claim 1, wherein the meson has a step formed by a step. 3. The impact tool according to claim 1, wherein the passage is a gap formed between the intermediate element and the seal material by the step.