JP2002239817A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fixed screw from falling from a tool holder at the time when the tool holder is removed from a tool main body on a power tool on which the tool holder to hold a head end tool on the tool main body is mounted by the fixed screw free to connect and disconnect to and from it. SOLUTION: In an electric angle drill in which a chuck device 20 is mounted on a head end of an output shaft 12 in the tool main body 10 by the fixed screw 30 free to connect and disconnect to and from it, the chuck device 20 can be fixed on the output shaft 12 by fastening a screw part 30a formed on a head end part of the fixed screw 30 in a screw hole 12c formed on the output shaft 12 after passing a screw hole 21b formed on a holder shaft 21 of the chuck device 20. Consequently, the fixed screw 30 remains mounted on the chuck device 20 as long as it is not rotated in the loosening direction when the chuck device 20 is removed from the output shaft 12, and it is possible to prevent its falling from the chuck device 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power tool such as an electric tool or an air tool which uses electric or pneumatic power as a power source and is used for a drilling operation or a tightening operation. The present invention relates to an attaching technique for attaching a tool holder (for example, a chuck device) for holding a tip tool to a tool body of a power tool.

[0002]

2. Description of the Related Art For example, in the case of an electric drill or an electric driver drill used for drilling work or tightening work,
A chuck device for holding a drill bit and a driver bit is attached to the tip of the drill body. When the size (diameter) of the drill bit to be used changes greatly, the chuck device may be replaced with a device corresponding to the drill bit. Therefore, in order to easily cope with such exchange, conventionally, a chuck device is detachably attached to a drill body using a fixing screw.

[0003]

However, in the case of the mounting structure using fixing screws, when the chuck device is removed from the main body, there is a possibility that the fixing screw or a washer for preventing loosening may fall off the chuck device and be lost. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to remove a tool holder for holding a tip tool from a tool body and to use the tool holder as a mounting part. An object of the present invention is to provide an improved power tool so that a fixing screw does not fall out of a tool holder.

[0005]

Means for Solving the Problems To achieve the above object, a power tool according to the present invention has a configuration as described in each of the claims. In the power tool according to the first aspect, the tool holder is attached to the tool body using a fixing screw having a screw portion, a shaft portion, and a head. That is, the fixing screw is rotated in the tightening direction, and after the screw portion of the fixing screw passes through the screw hole provided in the tool holder, the tool holder is fixed to the tool main body by tightening the screw portion into the screw hole provided in the tool main body. It has a configuration. Therefore, when the screw portion of the fixing screw is removed from the screw hole of the tool body and the tool holder is removed from the tool body, the fixing screw remains attached to the tool holder unless it rotates in the loosening direction. That is, it is possible to prevent the fixing screw from dropping from the tool holder.

In the power tool according to the second aspect, as a washer for preventing the fixing screw from being loosened, the power tool is loosened by applying an axial force to the mating surface against the rotation of the fixing screw in the loosening direction. A pair of washers having a wedge shape for preventing rotation in the direction is used. The washers exhibit a function of preventing loosening by abutting surfaces having wedge shapes with each other, and need to be set so that the wedge-shaped surfaces overlap. However, when the tool holder is removed from the tool body, the fixing screw is prevented from falling off as described above, so that the washer is prevented from falling off. As a result, the tool holder is re-assembled to the tool body. In this case, a setting mistake can be avoided.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 shows an electric angle drill as an example of a power tool. This electric angle drill 1 includes a tool body 10 extending in the front-rear direction,
And a chuck device 20 shown on the right side.
Although illustration is omitted in the case 11 of the tool main body 10,
An electric motor as a power source, a gear-type power transmission mechanism for transmitting the rotation of the electric motor, and the like are housed therein. Have been. In addition, in the case of the electric angle drill 1, as shown in the figure, the tip of the case 11 is bent into a substantially L shape. Therefore, the output shaft 12 is disposed so as to be perpendicular to the rotational driving axis of the power,
The case 11 is rotatably supported via a bearing 13, and a chuck device 20 as a tool holder of a tip tool is attached to the tip (the lower end in FIG. 1).

FIG. 2 shows a mounting structure of the chuck device 20.
It will be described based on. At the tip of the output shaft 12, a two-plane width portion 12a having two flat surfaces and a centering portion 12b are provided coaxially, and at the center of the axis of the two-plane width portion 12a and the centering portion 12b, A screw hole 12c is formed. The two-sided width portion 12a, the centering portion 12b, and the screw hole 12c constitute a mounting portion of the chuck device 20.

The chuck device 20 includes a holder shaft 21 detachably mounted on the output shaft 12, a sleeve 22 rotatably mounted on the holder shaft 21, and a holder shaft 2.
Three claws 23 arranged facing each other on the inner peripheral side of 1
And A screw hole (not shown) is formed on the inner peripheral side of the sleeve 22, and a screw portion (not shown) formed on the outer peripheral surface of the claw 23 is engaged with the screw hole. The claw 23 is supported movably along a direction inclined with respect to the axis of the holder shaft 21. For this reason,
When the sleeve 22 is rotated clockwise or counterclockwise, the claws 23 approach or move away from each other, whereby the drill bit inserted between the claws 23 is gripped or released. Note that the basic configuration and function of the chuck device 20 are conventionally known and do not require any particular change in the present embodiment.

The above-described chuck device 20 has the following structure for attachment to the output shaft 12. The holder shaft 21 has a counterbore 21 a and a screw hole 2.
1b and the connecting hole 21c are formed coaxially and continuously. The counterbore 21a is open at the front end face (lower end face in the figure) of the holder shaft 21, and the connecting hole 21c is open at the rear end face (upper end face in the figure) of the holder shaft 21. Screw hole 2
1b has the same diameter and the same pitch as the screw hole 12c of the output shaft 12. A pair of engagement walls 21d is formed on the rear end surface (upper end surface in the figure) of the holder shaft 21 with the connection hole 21c interposed therebetween. The interval between the engaging wall portions 21d is
The dimensions are set such that the two-plane width portion 12a of the output shaft 12 can be inserted without looseness. By inserting the two-plane width portion 12a of the output shaft 12 between the engagement wall portions 21d and inserting the centering portion 12b into the connection hole portion 21c, the chuck device 2
0 is fitted coaxially with the output shaft 12 so that it cannot rotate relative thereto.

The chuck device 2 fitted as described above
0 is fixed to the output shaft 12 by a fixing screw 30. The fixing screw 30 is connected to the screw hole 21 b of the holder shaft 21 and the output shaft 12.
Screw portion 30a formed to have a diameter capable of engaging with the screw hole 12c. The screw portion 30a is formed in a certain range from the tip of the fixing screw 30 to the head 30c. Further, the fixing screw 30 has a shaft portion 30b of a predetermined length having no screw between the screw portion 30a and the head portion 30c, and the shaft portion 30b is provided with a screw hole 21b of the holder shaft 21.
Is formed to have a diameter that can be inserted. The head 30c has a hexagonal hole for inserting a rod wrench.

The fixing screw 30 formed as described above is
After the gap between the three claws 23 in the chuck device 20 is greatly widened, the holder is inserted from the front end side of the holder shaft 21, and the screw portion 30 a at the front end is screwed into the screw hole 21 b of the holder shaft 21 to pass therethrough. The chuck device 20 is fixed to the output shaft 12 by being tightened in the screw hole 12c. At this time, the head 30c of the fixing screw 30 fits into the counterbore 21a, and the shaft 30b passes through the screw hole 21b. The fastening of the fixing screw 30 is performed using a bar wrench.

The head 30c of the fixing screw 30 and the counterbore 2
1a, a washer 40 (trade name Nord Lock) as shown in FIG. 3 for preventing the fixing screw 30 from loosening.
Is interposed. The washers 40 are used in pairs, and as shown, a wedge shape 40a for regulating rotation in the loosening direction is provided on one surface continuously in the circumferential direction, and as shown in FIG. Is formed with ribs (not shown) for slip prevention. The washer 40 having the above-described structure is set to be overlapped so that the wedge shapes 40a engage with each other. In the setting state, when the fixing screw 30 tries to rotate in the loosening direction, the wedge action of the mutually engaging wedge shapes 40a (relative movement along the inclined surface).
As a result, a force acts in the axial direction, and a loosening prevention function is obtained by the axial force. Thus, the chuck device 2
0 is attached to the output shaft 12 of the tool body 10 in a stable state without rattling.

In order to remove the chuck device 20 attached to the output shaft 12 as described above, first,
When the fixing screw 30 is rotated in the loosening direction while the screw 3 is largely opened, the screw portion 30a is screwed into the screw hole 1 of the output shaft 12.
Remove from 2c. Next, by pulling the holder shaft 21 toward the distal end, the two-plane width portion 12a and the centering portion 12 of the output shaft 12 are formed.
b can be removed.

In this state, the fixing screw 30 does not come off the holder shaft 21, as shown in FIG. That is, in order to remove the fixing screw 30 from the holder shaft 21, the screw portion 30a must pass through the screw hole 21b, and for that purpose, it is necessary to turn the fixing screw 30 in the loosening direction. From this,
When the chuck device 20 is detached from the output shaft 12, the fixing screw 30 does not fall off the chuck device 20. When the chuck device 20 is turned upside down,
The head 30c does not fall off because it is caught by the counterbore 21a. As described above, according to the present embodiment, when the chuck device 20 is replaced with another chuck device and stored, the fixing screw 30 and the washer 40 are prevented from dropping from the chuck device 20, and the loss is prevented. Can be avoided.

Further, as described above, when a pair of washers 40 exhibiting the original function by being set by overlapping the wedge-shaped surfaces 40a are used, the fixing screws 3
If 0 is a structure that gets out of the chuck device 20, even if it is not lost, there is a possibility that the mating surface may be mistaken when setting again. However, according to the present embodiment, since the washer 40 and the fixing screw 30 can be stored while being attached to the chuck device 20, the direction is not set erroneously at the time of re-assembly, and the assembling at that time is prevented. Work can be done easily.

The present invention is not limited to the illustrated embodiment, but can be appropriately modified without departing from the gist of the present invention. For example, an electric drill chuck device 2
Although the description has been made by taking 0 as an example, the present invention is not necessarily limited to this, and an electric screwdriver drill may be used. The power source for operating the tip tool is not limited to electric power, and may be applied to a power tool that uses other power such as manual operation or air pressure. In addition, the configuration in which the chuck device 20 is fixed to the output shaft 12 with one fixing screw 30 at the center of the shaft has been exemplified. However, depending on the type of the tool holder, a plurality of flange portions formed for mounting may be provided. It is also possible to adopt a configuration of fixing with a fixing screw. In the present embodiment, the holder shaft 21 of the chuck device 20 is fixed to the output shaft 12 with the fixing screw 30. However, for example, a tool holder can be connected to the output shaft 12 so as to be integrally rotatable, and In the case where it is constituted by a rotating shaft capable of holding a tip tool and a case rotatably supporting the rotating shaft, the case of the tool holder is fixed to the case 11 of the tool body 10. Screw 30
It is possible to carry out the embodiment in a mode of attaching with.

[0018]

As described in detail above, according to the present invention,
When the tool holder holding the tip tool is removed from the tool main body, a power tool can be provided in which the fixing screw as an attachment component does not fall off the tool holder.

[Brief description of the drawings]

FIG. 1 is a side view showing an electric angle drill as an example of a power tool.

FIG. 2 is a partial sectional view showing a mounting structure of the chuck device.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 is a drawing showing a state where the chuck device is detached from the tool body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric angle drill 10 Tool main body 12 Output shaft 12c Screw hole 20 Chuck device 21 Holder shaft 21b Screw hole 30 Fixing screw 30a Screw part 30b Shaft part 30c Head 40 Washer 40a Wedge shape

Claims (2)

[Claims] 1. A power tool comprising a tool body, a tool holder capable of holding a tip tool, and a fixing screw for detachably attaching the tool holder to the tool body, wherein the fixing screw comprises: By rotating in the tightening direction, after passing through the screw hole provided in the tool holder, a screw part to be screwed into the screw hole provided in the tool body, and the screw part is tightened to the screw hole in the tool body. In the state, a power tool having a shaft portion that penetrates a screw hole of the tool holder and a head that presses and fixes the tool holder toward the tool body. 2. The power tool according to claim 1, wherein a set of two washers is interposed between the head of the fixing screw and the tool holder. In the tightened state of the fixing screw, a wedge shape for preventing rotation in the loosening direction by applying an axial force to rotation of the fixing screw in the loosening direction on a mutual mating surface. Power tool characterized by the following.