JPH057150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an impact tool that can adjust the impact force for drilling holes in concrete, stone, etc.

[Prior Art] Conventionally, impact tools use a piston to drive a striker that strikes a bit within a cylinder.
The bit, striker, and piston were placed on the axis of the blow so that the blow would be the strongest.

The state in which such a blow is strongest is when the reciprocating motion of the striker resonates with the reflection after hitting the bit and the repulsion against the compression by the piston, so appropriate dimensions should be determined structurally. It was hot.

Under such conditions, the most compact and powerful impacting force was obtained, making it possible to obtain a small, high-performance impact tool.

However, although it is generally desirable for the work to have a compact and lightweight structure with strong impact force, there is a problem that if the impact is too strong, cracks may occur around the perforation in easily breakable materials such as tiles. There were cases where it was desired to drill with a weak impact force in order to determine the material and the location of the hole.

In conventional impact tools, when such a weak impact force is required, the electric motor of the drive source is turned on for a short period of time to utilize the instant at the start of the impact.

Although such a method is convenient for forming a guide hole for a bit in order to determine the position of a perforation, it is not possible to maintain a weak impact force.

For this reason, it is possible to limit the power supplied to the motor, but if the motor is operated for a long time at low power, the rotation of the motor is low, so the cooling fan does not function sufficiently, causing problems such as overheating.

[Problems to be Solved by the Present Invention] The present invention was made in view of the above circumstances, and it is easy to change the strength of the impact force of the impact tool, and it is suitable for various drilling operations. The purpose of the present invention is to provide an impact tool that is small, lightweight, and allows for comfortable work without causing problems such as overheating of the electric motor.

[Means for Solving the Problems] The present invention includes a shaft parallel to the axis on which the piston operates, a swash plate cam on this shaft to drive the piston, and a swash plate cam on the shaft. The swash plate cam is configured to be movable in the axial direction, and further includes an adjustment member for regulating movement of the swash plate cam, and an operating portion of the adjustment member extends to the outside to adjust the axial position of the swash plate cam. This solves the problem.

[Function] According to the configuration of the present invention, since the position of the swash plate cam is moved in the axial direction, the position in which the piston operates changes, and the compression action on the striker that operates between it and the bit changes. By moving the reciprocating motion of the striker away from the resonance point, the strength of the striking force can be adjusted.

[Example] The present invention will be explained 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. It is a principle diagram showing the operation.

In FIG. 1, the impact tool is configured such that a piston 2 reciprocates inside a cylinder 1, and is equipped with a striker 3 that moves within the cylinder 1 due to changes in air pressure caused by the reciprocating movement of the piston 2. It is being

A head 5 of a bit 4 is extended to one side of the movement of the striker 3, and the bit 4 has a cutting edge protruding to the outside of a tool body (not shown), and is designed to strike concrete, etc. (not shown). It is composed of

Further, a shaft 6 is provided which is parallel to the axis of impact on which the piston 2 reciprocates, and a swash plate cam 8 connected to the shaft 6 by a spline 7 is provided.

The swash plate cam 8 is connected to the piston 2 by a tappet 9.
The piston 2 is continuously spun, and the rotation of the shaft 6 causes the piston 2 to reciprocate.

The swash plate cam 8 is configured to be able to move in the axial direction along the shaft 6, and the switching portion 1 is rotatably attached to the case 10.
The swash plate cam 8 is fitted and connected to the eccentric shaft 12 of the swash plate cam 8, and is configured as an adjustment member that holds the swash plate cam 8 in the axial direction.

The eccentric shaft 12 serving as the adjustment member may be configured to move the swash plate cam 8 in the axial direction, and other methods are also possible.

For example, the same effect can be obtained by integrating the swash plate cam 8 and the shaft 6 and moving the shaft 6 by pushing it with the cam. Anything that can be moved and fixed at will is fine.

Furthermore, a gear 13 is formed at the end of the shaft 6 and meshes with a gear 14 configured to rotate the bit 4.

In FIG. 2, in the impact tool, the swash plate cam 8 is moved in the axial direction by the rotation of the switching part 11, and the tappet 9 is moved as shown by solid lines and dotted lines 9a and 9b.
Furthermore, the piston 2 is shown moving as shown in 2a and 2b, and the center point of the reciprocating movement is also shown.

In such a configuration, when the piston 2 reciprocates, the air pressure between the striker 3 and the piston 2 changes. The head 5 will be hit.

Head 5 of bit 4 by such striker 3
The impact is strongest when the piston 2, the head 5 of the bit 4, and the striker 3 are in the same position.

That is, when the striker 3 collides with the head 5 of the bit 4, is reflected toward the piston 2, and is further directed toward the bit 4 due to the compression of the piston 2, a kind of resonance phenomenon occurs, and the striker 3 efficiently strikes the bit 4. energy is transferred to

Therefore, when the switching part 11 is rotated, the position of the eccentric shaft 12 changes in the axial direction as shown by the solid line 12a and the dotted line 12b shown in FIG.
moves in the axial direction.

Then, the center of the reciprocating motion of the piston 2 is the solid line 2a
When the force changes as shown by the dotted line 2b, the strength of the blow changes.

Therefore, if the switching unit 11 is used in advance to display a strong hit at the position where the impact is strongest and to display a weak hit at the position where the impact is weak, it becomes possible to easily operate the player without making mistakes.

Changing the position of the swash plate cam 8 in this way not only makes it easier to operate from the outside as an adjustment mechanism, but it is also mechanically robust, allowing stable operation for long periods of time and preventing changes in performance. do not have.

Further, it is difficult to change the position of the striker 3, and it is easy to change the position of the head 11 of the bit 4 by replacing the bit 4, but it is difficult to make subtle adjustments. bit 4
Since it is necessary to prepare various kinds of devices, each type of device is inconvenient for the user.

Compared to such conventional situations, the means of the present invention is extremely effective and is an extremely preferable configuration for this type of impact tool.

[Effects of the Invention] According to the present invention, it is possible to easily adjust the strength of the impact force, and it can be easily applied to various types of work, and a highly reliable impact tool can be obtained. The effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of an impact tool according to an embodiment of the present invention, and FIG. 2 is a principle diagram showing its operation. 1... Cylinder, 2... Piston, 3... Striker, 4... Bit, 8... Swash plate cam, 12...
...eccentric shaft.

Claims (1)

[Claims] 1. An impact tool that strikes a bit by driving a striker with a piston in a cylinder, which comprises a shaft parallel to the axis in which the piston operates, a swash plate cam on this shaft to drive the piston, and a swash plate cam that drives the piston. The cam is configured to be movable in the axial direction of the shaft, and further includes an adjustment member for regulating the movement of the swash plate cam, and an operating portion of the adjustment member is extended to the outside so that the cam can be moved in the axial direction of the swash plate cam. An impact tool characterized by adjusting the position of.