JPH0544005Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric hammer drill.

[Prior Art] Conventionally, as a tool used for an electric hammer drill, as shown in US Pat. A circular drill) was known. The electric hammer drill to which this circular drill is attached also has a US Patent No.
There is a combination body made of balls shown in Publication No. 3741317, in which the combination body of an electric hammer drill engages with the recess of a circular drill, thereby transmitting rotation to the circular drill and preventing it from falling out within the width of the recess. It was on.

However, this type of circular drill, which has the functions of both transmitting rotation and preventing it from coming off through the coupling body, has the problem that the concave part that comes into contact with the coupling body wears out relatively quickly, resulting in a short lifespan of the circular drill. Ta.

In order to solve such problems, the special public
As shown in Japanese Patent No. 47079, a drill has been proposed in which a groove is provided in the axial direction in addition to the recess provided in the circular drill described above (hereinafter referred to as a grooved drill). The electric hammer drill to which this grooved drill is attached is equipped with a convex body that engages with the axial groove of the grooved drill in addition to a coupling body that engages with the recess of the grooved drill. Rotation is transmitted to the grooved drill by engagement between the groove and the convex body of the electric hammer drill, and further, the engagement between the concave part of the grooved drill and the combined body of the electric hammer drill prevents the electric hammer from coming off. In other words, the grooved drill shown in Japanese Patent Publication No. 60-47079 has the function of transmitting rotation and preventing it from coming off, whereas the circular drill has the function of transmitting rotation and preventing it from coming off by combining the recess and the electric hammer drill. By separately performing the function by engaging the groove of the grooved drill with the convex body of the electric hammer drill, there is an advantage that the concave portion of the grooved drill is less likely to wear out, and as a result, the life of the drill is extended.

Under these circumstances, there is a need for an electric hammer drill that can be attached to both a circular drill and a grooved drill.

[Problems to be solved by the invention] Conventionally, electric hammer drills made for the purpose of mounting circular drills have not been provided with a convex body that engages with the groove of a grooved drill. When a grooved drill is attached to an electric hammer drill,
There was a problem that the effect of the grooved drill, that is, the advantage of long life could not be brought out.

In addition, electric hammer drills made for the purpose of attaching a grooved drill were equipped with a convex body that engaged with the groove of the grooved drill. I had a problem with not being able to install it.

The purpose of the present invention is to provide an electric hammer drill that can be equipped with both a circular drill and a grooved drill, and which can bring out the effects of the grooved drill when the grooved drill is attached. be.

[Means for solving the problem] This is achieved by disposing a sleeve having a convex body that engages with the groove of the grooved drill inside the holding portion via a spring.

[Operation] The sleeve is constantly pressed toward the tool by the spring, and when the grooved drill is inserted into the holding part, the groove and the sleeve engage with each other.
Also, when the circular drill is inserted into the holding part,
The convex body of the sleeve that engages with the groove of the grooved drill is pushed axially rearward by the circular drill end face and moves while compressing the spring.

[Example] An example of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional side view showing a state in which a drill whose shank section has a circular cross-sectional shape is mounted in a holding section. FIG. 2 is a sectional view taken along the line a-a when a drill whose shank portion has a square cross-sectional shape (hereinafter referred to as a square drill) is installed in the holding portion of FIG. 1. FIG. 3 is a sectional view showing the shape of the inner wall of the holding portion shown in FIG. 1. FIG. FIG. 4 is a longitudinal sectional side view showing the grooved drill installed in the holding part. Figure 5 is the 4th
It is a sectional view taken along the line bb in the figure. In the figure, 1 is a drill, 2 is a holding part that holds the drill 1, 3 is a cylinder that transmits rotation and axial movement to the holding part 2, and 4
5 is a ball that engages with a groove 4' provided in the holding part 2 to transmit the movement of the cylinder 3 to the holding part 2, and 5 engages with a recess 5' provided in the shank part of the drill 1 to 6 is a holder that engages or disengages the joint 5 with a recess 5' provided in the shank portion; 7 is a holder that is pressed in the axial direction of the holder 2 to connect it; 8 is a stopper of holder 6; 9 is a sleeve that engages with the grooved drill; 10 is a striking body that transmits a blow to drill 1; a spring that determines the operating position;
2 is a grooved drill, 13 is a groove, and 14 is a convex body provided on the sleeve 9. As shown in FIGS. 1 to 3, when installing a circular or square drill into the holding portion 2, the holder 6 is first moved axially rearward against the force of the spring 7. When the holder 6 moves rearward in the axial direction, the combined body 5 becomes movable in the radial direction of the axis, and a drill can be attached. When the circular drill is installed in the holding part 2, the sleeve 9 is moved axially rearward with the convex body 14 provided on the sleeve 9 in contact with the end surface of the circular drill. Moreover, when the square drill 15 is installed in the holding part 2, the square drill 1 is attached to the end surface of the sleeve 9.
The four corners of 5 come into contact and move the sleeve 9 axially rearward. Fig. 3 shows the inner wall shape of the holding part 2 that can hold both the circular drill 1 and the square drill 15, and has a composite shape that is punched out by overlapping a circle and a square. Since it protrudes beyond the circumference, it can hold either a circular or square drill. 4 to 5 are longitudinal cross-sectional views showing the state in which the grooved drill is installed in the holding part 2, and its b-b
FIG. Since the cross-sectional shape of the grooved drill 12 and the inner surface shape of the sleeve 9 match, the sleeve 9 does not move backward in the axial direction, unlike when the circular drill 1 or the square drill 15 is installed.
The groove 13 of the grooved drill 12 engages with a convex body 14 provided on the sleeve 9 to transmit rotation to the grooved drill 12.

As described above, according to the present invention, it is possible to provide an electric hammer drill to which a drill of the type such as the circular drill 1 or the square drill 15 can be attached, and furthermore, the grooved drill 12 can also be attached. Moreover, when the grooved drill 12 is attached,
Groove 13 of grooved drill 12 and convex body 1 of sleeve 9
4 engages with each other, the impact force applied to the shank portion of the grooved drill 12 can be distributed to these inner walls and reduced, thereby extending the life of the tool. Also, since various types of drills can be easily attached, the work range can be expanded and the versatility of the tool can be increased.

[Effects of the invention] The present invention can provide an electric hammer drill that can be equipped with both a circular drill and a grooved drill, and can bring out the effects of the grooved drill when the grooved drill is attached. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing a state in which a drill whose shank section has a circular cross-sectional shape is mounted in a holding section. FIG. 2 is a sectional view taken along the line a-a when a drill whose shank section has a square cross-sectional shape is installed in the holding section of FIG. 1. FIG. 3 is a sectional view showing the shape of the inner wall of the holding portion shown in FIG. 1. FIG. FIG. 4 is a longitudinal sectional side view showing the grooved drill installed in the holding part. FIG. 5 is a sectional view taken along line bb in FIG. 4. 1 is a drill, 2 is a holding part, 3 is a cylinder, 4 is a ball, 4' is a groove, 5 is a coupling body, 5' is a recessed part, 6 is a holder, 7 is a spring, 8 is a stopper, 9 is a sleeve, 10 is a Impacting body, 11 is a spring, 12
13 is a grooved drill, 14 is a convex body, and 15 is a square drill.

Claims (1)

[Scope of utility model registration request] A holding part that holds a drill, transmits rotation to the drill, and prevents the drill from coming off in the axial direction, and a coupling body disposed on the holding part that engages with a recess provided in the drill. In the electric hammer drill, a sleeve that rotates together with the holding part and is movable in the axial direction of the drill is disposed within the holding part, and a convex body is provided on the inner wall of the sleeve,
The electric hammer drill is further characterized in that a spring is provided in the holding portion to press the sleeve toward the tip of the shaft of the drill.