JPH01316179A - Percussion tool - Google Patents

Abstract

PURPOSE:To actively attenuate and cut off the vibration generated by the reaction of a bit by oscillatingly securing on a percussion body through a spring the first magnet magnetized in the circumferential direction, and fixedly mounting the second magnet opposedly facing the first magnet in the axial direction and in a way to rotate synchronously with the rotation of an electric motor for the percussion body. CONSTITUTION:With the percussion of a bit 3 by a percussion body 4, the reaction is transmitted to the percussion body 4. At that time, the first magnet 9 installed on the percussion body 4 through a spring 8 is vibrated in the axial direction by the second magnet 10 which rotates in synchronization with an electric motor 5 driving the percussion body 4. Since the vibration of the first magnet 9 is in a relationship to set off the vibration of the percussion body 4 by the bit, the vibration generated by the reaction of the bit 3 is actively attenuated and cut off to lessen the vibration transmitted to a handle 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a w1 striking tool that strikes a bit in the axial direction.

[Prior Art] In an impact tool that strikes a bit in the axial direction, the tip of the bit is in contact with a hard member such as concrete, so when the bit is struck in the axial direction, the reaction force is in the opposite direction to the bit strike. Occurs on.

Such reaction force is transmitted to the m-type tool body and is felt by the operator's hands as severe vibration, causing various problems to the operator.゛For this reason, attempts have been made to interpose a cushioning member such as cushion rubber between the main body and the handle of the impact tool, but if a cushioning member with a large capacity is used to sufficiently absorb vibrations, it will be difficult to operate the handle. There was a limit to the absorption of passive vibrations by the cushioning member, as this would cause problems in terms of performance.

"Problems to be Solved by the Invention" The present invention has been made in view of these circumstances,
It is an object of the present invention to provide an impact tool that actively prevents the generation of vibrations instead of passively absorbing vibrations using a shock absorbing member, etc., and can protect a worker from damage.

[Means for Solving the Problems] The present invention provides a striking body that strikes a bit with a circumferentially magnetized first magnet which is swung in the axial direction of striking via a spring. The problem is solved by providing a second magnet that faces the magnet and is fixed so as to rotate in synchronization with the rotation of the electric motor that drives the impacting body and not to move in the axial direction.

[Operation] When the striking body strikes the bit, the second magnet rotates in synchronization with this striking.

The first magnet magnetized in the circumferential direction generates vibration in the axial direction by the second magnet rotating in opposition to the first magnet.

This vibration of the first Ra stone is caused by the rotation of the second magnet, which generates an axial force due to its magnetic attractive force and repulsive force. The vibration is transmitted to the striking body through the spring, and cancels out the vibration transmitted from the striking body to the first magnet via the spring.

Therefore, when the bit with a load is struck, its reaction force is transmitted to the striking body, but the first magnet provided in the striking body is vibrated in the axial direction by the second magnet, and the vibration of the first magnet is transmitted to the striking body. The occurrence of vibration is reduced by canceling out the vibration of the striking body caused by the bit.

``Example'' The present invention will be described based on an example shown in the drawings. FIG. 1 is a longitudinal cross-sectional view of a main part of an impact tool according to an example of the present invention, and FIG. FIG.

In FIG. 1, the impact tool is equipped with a handle 2 at the rear end of a frame 1, and a bit 3 at the tip.

The bit 3 is provided in a striking body 4, and the striking body 4 consists of a mechanism such as a crank or a swash plate cam.
It constitutes an a-ellipse in which the rotation of No. 15 is converted into reciprocating motion, and is configured to perform impact in synchronization with the rotation speed of the electric motor 5.

Further, a vibrating body 7 is provided on a shaft 6 that transmits power to the striking body 4, and is configured to generate vibrations in synchronization with the rotation of the electric motor 5.

In FIG. 2, the vibrating body 7 has a first ff1 magnetized in the circumferential direction via a spring 8 at the axial end of the impact #C4.
A stone 9 is provided, and this first magnet 9 (an opposing second magnet 10 which is also magnetized in the circumferential direction) is fixed to the shaft 6.

In such a configuration, in the impact tool, when the electric motor 5 rotates, the impact body 4 operates to impact the bit 3,
The bit 3 can crush or perforate hard materials such as concrete.

When the bit 3 is struck while in contact with a load such as concrete, the reaction force of the strike is transmitted to the striking body 4 via the bit 3.

However, the striking body 4 is equipped with a first magnet 9 via a spring 8, and this first magnet 9 generates vibration in the axial direction by the second magnet 10, and this vibration causes the striking body 4 to vibrate in the axial direction. By being in the opposite direction to the vibration, the vibration of the striking mechanism 4 is attenuated, and moreover, it is no longer transmitted from the bit 3 side of the frame 1 to the handle 2 at the rear end.

Such vibrations of the first magnet 9 occur because the first magnet 9 is magnetized in the circumferential direction and the second magnet 1o rotates facing each other. In the meantime, magnetic attraction and repulsion occur periodically, and since the second magnet 10 is fixed in the axial direction, the first magnet 9 vibrates in the axial direction.

The first magnet 9 is connected to the striking body 4 via the spring 8.
Since the impact body 4, which is the reaction force of the bit 3,
The energy of the first magnet 9 and the energy of the first magnet 9 are combined at the tin ring 8.

Such an operation can isolate the vibration of the bit 3 between the vibrating body 7 of the frame 1 and the striking body 4, and prevent the vibration of the bit 3 from passing through the frame 1 to the handle 2. However, since it is driven by the electric motor 5, it can be easily synchronized, and the load on the bit 3 may be increased. Even if the rotational speed of the rotor 5 fluctuates, synchronization is not impaired and stable operation can be performed.

[Effects of the Invention] According to the present invention, since the first magnet is provided in the striking body and configured to vibrate in synchronization with the striking of the bit, the vibration generated by the reaction force of the bit can be actively damped. The vibrations transmitted to the handle are reduced, and the operator is protected, which is extremely effective.

[Brief explanation of the drawing]

FIG. 1 is according to an embodiment of the present invention? It is a longitudinal cross-sectional view of the principal part of II hammer tool, and FIG. 2 is an enlarged longitudinal cross-sectional view of the principal part. 1...Frame, 2...Handle, 3...
・Bit, 4...Blowing body, 5...Electric motor, 7.
... Vibrating body, 8... Spring, 9... First magnet, 10... Second magnet.

Claims (1)

[Claims] In an impact tool that strikes a bit in the axial direction, a first magnet magnetized in the circumferential direction is provided in the striking body that strikes the bit via a spring so as to swing in the axial direction of the strike, and the first magnet is opposed to the first magnet. An impact tool comprising: a second magnet that rotates in synchronization with the rotation of the electric motor that drives the impacting body and is fixed so that it does not move in the axial direction.