JPH08126905A - Tool fixing device - Google Patents

Abstract

PURPOSE: To provide a tool fixing device capable of being manually attached and detected without using a tool. CONSTITUTION: In a tool fixing device, a first flange 12 is provided on a nut part 11 to be screwed with a spindle 9, and a second flange 14 to press a tool 21 is provided, an intermediate member 13 to be turned through balls 16a, 16b is provided between the flanges, an end part 17c of a groove where these balls 16a, 16b are rolled is deep so as to evacuate the balls 16a, 16b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a tool fixing device for fixing a tool such as a grindstone of a disc grinder to a spindle.

[0002]

2. Description of the Related Art A tool fixing device for fixing a tool such as a grindstone of a disk grinder to a spindle often needs a new tool because the tool is worn, and in order to facilitate the replacement of the tool. Usually, the structure is such that the spindle is screwed and fixed with a nut.

The conventional technique as described above will be described with reference to the drawings. FIG. 6 is a longitudinal sectional view of a main part showing a tool portion of a conventional disc grinder, and FIGS. 6 and 8 respectively show a disc grinder and the like. 3 is an example of a tool fixing device used in the electric tool of FIG.

In FIG. 6, in the disc grinder, a spindle 3 extends from an electric motor 1 through a speed reducer 2, a grindstone 4 as a tool is attached to the spindle 3, and screw portions 5a and 5b of the spindle are provided. Whetstone 4
The nuts 6a and 6b are screwed together so as to sandwich.
A half-moon shaped grindstone cover 7 is provided so as to cover approximately half of the grindstone 4 on the side of the electric motor 1 in order to avoid a risk when the grindstone 4 is damaged. Further, as shown in FIG. 7, there is also seen a simple structure in which two nuts 5c and 5d are screwed into a threaded portion 5c to hold the grindstone 4. further,
As shown in FIG. 8, there is also a method in which the grindstone 4 is held between the flanges 6e and 6f and the bolt 8 is screwed and fixed to the tip portion of the spindle 3.

In these configurations, the grindstone 4 can be easily removed from the spindle 3 by removing the nut 6b, and the tool replacement has a simple and convenient structure. However, in such a configuration, when tightening or loosening the nut 6b, it has been necessary to tighten or loosen the nut 6b with a tool using a tool such as a spanner. This kind of work is not easy because the grindstone 4 easily rotates together with the spindle 3 and it is not easy.
It had to be equipped with a stopper etc. that could restrain the rotation inside. Further, since the grindstone 4 has a constant mass, the screws 5a, 5b and the nuts 6a, 6b are normally screwed in such a direction that the nuts 6a, 6b are tightened with respect to the screw portions 5a, 5b when the electric motor 1 is started. Forming a relationship. With such a configuration, the nuts 6a and 6b are tightened each time the electric motor 1 is started, and the nuts 6a and 6b are screwed into the screw portions 5a and 5b even when a load is generated on the grindstone 4.
Since it is tightened with respect to 5b, the problem that the grindstone 4 falls off the spindle 3 does not occur, and it can be used with peace of mind. However, when the motor 1 is stopped, the inertia of the rotating grindstone 4 causes the grindstone 4 to generate a relative torque with respect to the spindle 3 in a direction opposite to that at the time of starting. For this reason, particularly when the electric motor 1 is provided with a brake circuit or the like, a relative torque larger than that at the time of start-up is generated, the grindstone 4 rotates, and the nuts 6a and 6b rotate, and the nut portions 6a and 5b are rotated. 6a and 6b were sometimes dropped.

In the example shown in FIG. 8, even if the grindstone 4 rotates with respect to the spindle 3, the bolt 8 is not directly subjected to torque, and therefore the grindstone 4 does not fall off from the spindle 3. However, in the example of FIG. 8, since the inner screw is formed on the spindle and the bolt 8 is screwed,
When the outer diameter of the spindle 3 is small and the outer diameter of the bolt 8 is small, the outer diameter of the bolt 8 is inevitably small, resulting in insufficient strength and unsuitable for practical use.

[0007]

Problems to be Solved by the Invention FIGS. 6, 7 and 8
In the examples shown in 1), there is a problem that the nut cannot be sufficiently tightened unless a tool such as a spanner is used for the nut. Further, when the screw direction and the like are configured to be tightened at the time of starting, a problem arises in that a tool having a large force must be used when the screw is gradually tightened at the time of starting and removed. However, it was necessary to firmly tighten the nut with a spanner or the like so that the whetstone would not rotate and the nut would not loosen when the electric motor was stopped.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a tool fixing device which can be easily and securely attached and removed by hand without using a tool.

[0009]

According to the present invention, a nut is provided with a first flange when screwed into a spindle, and a second flange is provided through an intermediate member which rotates along the first flange. The intermediate member to be rotatable and axially movable with respect to the nut portion, and the second flange to the nut portion so as to be restricted in the rotational direction and axially movable. (1) A groove is provided on both surfaces of the flange and the intermediate member facing each other, and a ball having an outer diameter larger than the depth of the groove is interposed, and the groove is facing both surfaces of the intermediate member and the second flange. The problem is solved by arranging a ball and interposing a ball to deepen the end of at least one of the grooves in the axial direction.

[0010]

[Operation] When the nut portion is screwed onto the spindle, the nut portion moves axially along the spindle,
When a tool such as a grindstone is attached to the spindle, the tool can be pressed by the second flange. Then, by rotating the intermediate member, the balls interposed in each groove move along the groove,
Since the groove is deep when the ball reaches the end of the groove, the ball can move in the axial direction, and the force for pressing the tool of the second flange is released. When the second flange does not press the tool, the nut has no friction required for screwing the spindle, and the nut can be easily rotated by hand. The tool can be removed from the spindle without using the tool. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment shown in the drawings. FIG. FIG. 2 is a longitudinal cross-sectional view of a main part for explaining the operation of the tool fixing device shown in FIG. FIG. 3 is an exploded view of the essential parts for explaining the operation of the tool fixing device of the present invention. FIG. 4 is an exploded view of the essential parts for explaining the operation of the tool fixing device of the present invention. FIG. 5 is a lateral cross-sectional view of the main part of the present invention. In FIG. 1, the tool fixing device has a spindle 9 connected to an electric motor via a speed reducer (not shown), and is configured to rotate at low speed and high torque. A screw portion 10 is formed at the tip portion of the spindle 9, and a nut portion 11 is provided when screwed into the screw portion 10. The nut portion 11 has
A first flange 12 is provided which spreads in a radial direction in the form of a brim, and the intermediate member 1 which rotates along the first flange 12 is provided.
A second flange 14 is provided via the third flange 14. The intermediate member 13 is loosely fitted so as to be rotatable coaxially with the nut portion 11 and axially movable. The second flange 14 is the D cut portion 1 of the nut portion 11.
8 is fitted to the spindle 9 and is restrained in the rotation direction with respect to the spindle 9, and is configured to be movable in the axial direction.

Further, the first flange 12 and the intermediate member 13
Grooves 15a and 15b facing each other on both surfaces facing each other, and a ball 16a having an outer diameter larger than the depth of the groove is interposed, and grooves facing both surfaces facing the intermediate member 13 and the second flange 14. Balls 16b provided with 17a and 17b
The end portion 17c of the one groove 17b is deepened in the axial direction.

The nut portion 11 is provided with a stopper 19 for preventing the second flange 14 from falling off, and a spring 20 is suspended between the first flange 12 and the intermediate member 13. The intermediate member 13 is constantly urged against the first flange 12 so as to rotate in a fixed direction. The member held between the spindle 9 and the second flange 14 is a tool 21 composed of a grindstone or the like.

The tool 21 is constructed so as to be sandwiched between the end portion of the spindle 9 and the second flange 14, and the second flange 14 is secured by screwing the nut portion 11 fitted into the screw portion 10. When moved to the tool 21 side, the intermediate member 13 and the ball 16 interposed between the first flange 12 and
The second flange 14 is configured to act so as to press the tool 21 via a and 16b.

In FIG. 2, in the tool fixing device, the ball 16a and the ball 1 are rotated by rotating the intermediate member 13.
6b rolls along the grooves 15a, 15b, 17a, 17b, respectively, and when the ball 16b reaches the end 17c of the groove, the end 17c of the groove is deeply formed in the axial direction, so that the ball 16b is formed. It is configured so that it can be retracted into the end portion 17c of the groove to reduce the distance between the intermediate member 13 and the second flange 14. In such a state, the second flange 14 that was pressing the tool 21
Can be slightly moved to the side of the first flange 12, so that the pressing is released.

In FIGS. 3 and 4, the first flange 1
The second and second flanges 14 are configured not to move relative to each other, but to move only the intermediate member 13, and meanwhile, the grooves 15a and 15b and the grooves 17a and 17b.
The balls 16a and 16b interposed between the balls 16a and 16b are configured to roll as the intermediate member 13 moves.
The balls 16a, 16b have an axial dimension of the grooves 15a, 15b and the grooves 17a, 17b, that is, a depth smaller than the outer diameter of the balls 16a, 16b, and the first flange 12 and the intermediate member 13 The second flange 14 and the intermediate member 13 are configured so as not to contact each other. Further, when the ball 16b reaches the end 17c of the groove, the ball 16b enters the end 17c of the deepened groove,
The flange 14 and the intermediate member 13 are configured to act so as to reduce the distance between them.

The intermediate member 13 is urged by the spring 20 shown in FIGS. 1 and 2 so as to be in the state of FIG. 3, and the first flange 12 and the second flange 14 are normally provided. It is configured to have a large interval.

In FIG. 5, the structures of the grooves 15a and 15b and the grooves 17a and 17b are the same as those of the first flange 12 and the second flange 12.
It is formed in a semicircular shape along the rotation direction of the intermediate member 13 that moves relative to the flange 14. Then, one end of the spring 20 is fixed to the second flange 14, and is arranged at at least three places.

In such a structure, the tool fixing device is
After fitting the tool 21 to the spindle 9, the second flange 1
4 first, screw part 10 of spindle 9 to nut part 11
Screw together. Then, the intermediate member 13 is rotated to the extent that the tool 21 is tightened.

At this time, the intermediate member 13 includes the balls 16a,
16b through the first flange 12 and the second flange 1
4 is rotated so that the second flange 14 is pressed by the tool 21. Then, when the electric motor is started, the nut portion 11 acts on the screw portion 10 so as to be tightened, and the tool 2
1 is firmly clamped and held by a tool fixing device.

When the tool 21 is replaced by removing such a tool fixing device from the spindle 9, when the intermediate member 13 is rotated against the spring 20, the intermediate member 13 is moved to the first position.
Ball 16 for flange 12 and second flange 14
Since they are in contact with each other via a and 16b, they can rotate with relatively low resistance. Then, the ball 16b reaches the end 17c of the groove, and the ball 16b reaches the end 17c of the groove deepened.
b is fitted, the gap between the second flange 14 and the intermediate member 13 becomes smaller, and the pressing of the tool 21 by the second flange 14 is released. Therefore, the tool fixing device can be rapidly rotated without resistance and removed from the spindle 9 along the threaded portion 10. Therefore, the tool 21 can be easily removed from the spindle 9 and replaced.

When the tool fixing device is removed from the spindle 9, the second flange 14 is reset to the protruding state, and when the tool is screwed into the spindle 9 to press the tool 21, the second flange 14 is protruding state. Becomes

[0023]

According to the present invention, a tool such as a grindstone can be replaced by hand without using a tool such as a spanner despite the simple structure. It is extremely convenient and can be easily removed by hand even when the nut portion fixing the tool is tightly tightened, and the effect in actual use is extremely large.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a tool fixing device showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an essential part for explaining the operation of the tool fixing device shown in FIG.

FIG. 3 is an exploded view of a main part for explaining the operation of the tool fixing device of the present invention.

FIG. 4 is an exploded view of essential parts for explaining the operation of the tool fixing device of the present invention.

FIG. 5 is a transverse cross-sectional view of the main parts of the present invention.

FIG. 6 is a longitudinal sectional view of an essential part showing a tool portion of a conventional disc grinder.

FIG. 7 is an example of a tool fixing device used for a power tool such as a conventional disc grinder.

FIG. 8 is an example of a tool fixing device used in a power tool such as a conventional disc grinder.

[Explanation of symbols]

 9 ... Spindle 10 ... Screw part 11 ... Nut part 12 ... First flange 13 ... Intermediate member 14 ... Second flange 15a, 15b, 17a, 17b ... Groove 16a, 16b: Ball 19: Stopper 20: Spring 21: Tool

Claims (1)

[Claims] 1. A first flange is provided on a nut portion when screwed to a spindle, and a second flange is provided via an intermediate member that rotates along the first flange, and the intermediate member is attached to the nut portion. It is possible to rotate and move in the axial direction,
The second flange is constrained in the rotational direction with respect to the nut portion and is configured to be movable in the axial direction. Further, a groove facing both the facing surfaces of the first flange and the intermediate member is provided and the groove is provided. A ball having an outer diameter larger than the depth of the groove is provided, grooves are provided so as to be opposed to both of the facing surfaces of the intermediate member and the second flange, and the ball is interposed. Tool fixing device characterized by being deepened in the.