JPH07328955A - Hammer drill - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to a clutch mechanism portion of a hammer drill including a striking mechanism portion and a rotation transmitting mechanism portion, and an object of the present invention is to provide an inexpensive and compact and lightweight structure. It is to provide a three-mode switching device. [Structure] An oscillating body 4 and a pinion 5 which are rotatably engaged with each other on an intermediate shaft 3 are arranged in series, and are engaged with respective steel balls 7. Further, a ball holder 6 is mounted on the outer periphery of the ball holder 6 so as to be movable in the axial direction of the intermediate shaft 3. A spring 8 is arranged between the ball holder 6 and a shaft C snap ring 17 attached to the intermediate shaft 3 to constantly urge the ball holder 6. In such a structure, when the ball holder 6 is moved to the tip side by operating the switching lever 9, it is possible to sequentially switch to three modes of rotation and striking, only striking, and only rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for switching impact transmission and rotation transmission to a tip tool of a hammer drill having an impact mechanism and a rotation transmission mechanism.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Laid-Open No. 3-504697, a conventional device has a structure in which an oscillating body for converting a rotary motion into a reciprocating motion engages and disengages by axial movement of an intermediate shaft. Therefore, the clutch mechanism is an expensive one with many parts.

[0003]

The conventional hammer drill cannot be used as a dedicated hammering tool because two modes of rotation and hammering or rotation alone are the mainstream and there is no hammering only mode. Also, some hammer drills that have the functions of rotation and striking, rotation only, and striking only mode have the three-mode function because the intermediate shaft moves in the axial direction as described in the prior art. However, there is a problem that the cost increases and the cost increases.

An object of the present invention is to provide a simple and inexpensive hammer drill having a three-mode function.

[0005]

The above object is to provide an intermediate shaft and an oscillating body for converting the rotational motion of the motor transmitted to the intermediate shaft into a reciprocating motion and a pinion for transmitting the rotation to the tip tool.
Each steel ball moves in a direction orthogonal to the axial direction of the intermediate shaft to connect the intermediate shaft and the engaging portion. The ball holder, which is located on the outer peripheral side of the steel ball and moves the steel ball by axial movement of the intermediate shaft, and the spring interposed between the ball holder and the shaft C, which is mounted on the intermediate shaft, are used to perform the striking motion and the rotating motion. This is achieved by providing independent engaging and disengaging clutches. Further, by setting the engagement relationship between the ball holder and the steel ball in the order of rotation, striking, only striking, and only rotation, the ball holder or the hammer drill body can be made compact and lightweight.

[0006]

The ball holder of the switching device constructed as described above is constantly pressed by the spring toward the oscillating body, and is held stationary at a predetermined position by the switching lever from outside the main body frame. For example, the state in which the ball holder is located on the side of the rocking body is the rotation and striking mode.
When the hammer drill main body is started in this state, the steel balls try to move in a direction orthogonal to the axial direction of the intermediate shaft, but the movement of the steel balls is restricted by the inner circumference of the ball holder. Further, the state in which the ball holder is located on the tip side is the rotation only mode. That is, the steel ball moves to the concave portion on the inner periphery of the ball holder, and the engagement between the intermediate shaft and the sliding body is disengaged, and the striking motion is blocked.
On the other hand, when the ball holder is located in the middle, it is the only striking mode.

[0007]

EXAMPLE An example of the present invention will be described with reference to FIGS. The rotational movement of the motor 1 passes through the first gear 2 and
It is transmitted to the intermediate shaft 3. An oscillating body 4 and a pinion 5 which are rotatably engaged with each other are arranged on the intermediate shaft 3 and are engaged with each other by a plurality of steel balls 7. Further, a ball holder 6 is mounted on the outer periphery of the ball holder 6 so as to be movable in the axial direction of the intermediate shaft 3. A spring 8 is provided between the ball holder 6 and a shaft C ring 17 attached to the intermediate shaft 3, and the ball holder 6 is constantly pressed against the rocking body 4 side. It is restrained and held in place. Therefore, the rocking body 4 side is a striking switching clutch, and the pinion 5 side is a rotation switching clutch, which are arranged in series on the intermediate shaft 3. The rotary motion transmitted to the oscillating body 4 is converted into reciprocating motion, causing the piston 12 to reciprocate, and the striker 1
3. The impact is transmitted to the tip tool 15 via the intermediate impactor 14. On the other hand, the rotational movement transmitted to the pinion 5 is transmitted to the cylinder 11 which is claw-engaged with the second gear 10 and transmitted to the tip tool 15 via the steel ball 18.
That is, this state is the rotation + striking mode shown in FIG. 2, and when the hammer drill main body is started, the steel ball 7 tries to move in the direction orthogonal to the axial direction of the intermediate shaft 3, but the ball holder 6
The movement of the steel ball 7 is restricted on the inner circumference.

Next, FIG. 3 shows a state in which the ball holder 6 is moved to the tip end side by operating the switching lever 9. This is a striking-only mode, and when the motor 1 is started, the steel ball 7 of the rotation switching clutch moves to the recess 6a provided inside the ball holder 6 and releases the rotation transmission. FIG. 4 shows a state in which the ball holder 6 is further moved to the tip side. This is a mode of rotation only, and when the motor 1 is started, the steel ball 7 of the percussion switching clutch moves to the recess 6a provided inside the ball holder 6 to release the percussion transmission. On the other hand, since the rotation switching clutch regulates the steel balls 7 on the inner peripheral surface of the ball holder 6, rotation can be transmitted. On the contrary, in order to change from the clutch disengaged state to the engaged state, the spring 8 constantly applies pressure to the ball holder 6, so that the inclined portion provided inside the ball holder 6 is pressed by the spring 8 and its component force is applied. Steel ball 7 with intermediate shaft 3
It is pushed into and engaged with the concave portion of.

[0009]

According to the present invention, it is possible to provide a hammer drill equipped with a simple and inexpensive three-mode switching device which can be made compact and lightweight.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an embodiment of a hammer drill switching device according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing the state of rotation and impact of the hammer drill according to the present invention.

FIG. 3 is an enlarged partial cross-sectional view showing a state where only the hammer drill according to the present invention is hit.

FIG. 4 is an enlarged partial cross-sectional view showing only a state of rotation of the hammer drill according to the present invention.

[Explanation of symbols]

1 is a motor, 2 is a first gear, 3 is an intermediate shaft, 4 is an oscillating body, 5 is a pinion, 6 is a ball holder, 7 is a steel ball, 8
Is a spring, 9 is a switching lever, 15 is a tip tool, 16
Is the body frame.

Claims (2)

[Claims] 1. A rotation transmission mechanism unit for transmitting rotation of a motor to an intermediate shaft via a first gear, and a rotation mechanism for transmitting rotation to an impact tool unit and a tip tool which are connected via an oscillating body for converting rotational motion into reciprocating motion. In a hammer drill equipped with
The rocking body and the pinion rotatably fitted on the intermediate shaft are respectively connected to the intermediate shaft by steel balls, and the steel balls are independently arranged in series on the intermediate shaft. And a hammer drill. 2. A ball holder located on the outer circumference of the steel ball is pressed against the rocking body by a spring, and slides on the intermediate shaft by operating a switching lever from outside the body frame. The hammer drill according to claim 1, wherein the hammer drill is composed of one ball holder.