JP3043932B2 - Chuck mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck mechanism, for example, a chuck mechanism suitable for use in a dental treatment for removably attaching a blade to a turbine head, a contra head, and the like.

[0002]

2. Description of the Related Art FIG. 3 is a view for explaining a conventional example of a dental turbine head provided with a chuck mechanism.
1 is a rotary shaft rotatably mounted on a head case 2 via a bearing 3, 4 is a turbine blade protruding radially on an outer peripheral wall surface of an intermediate portion of the rotary shaft 1, 5 has an inner diameter larger than that of other portions. A cylindrical chuck member having a small rear portion 5a and a slit 5b cut in the center wall direction in a tube wall near the small rear portion 5a. The other parts (part 5a) are loosely inserted into the rotating shaft 1 as shown in the figure. Reference numeral 6 denotes a tubular opening / closing body formed by cutting out a tube wall at the tip and forming a projection 6b having an inclined surface 6a. The opening / closing body 6 is in a state where the tip of the projection 6b is inserted into the slit 5b. Thus, the rotary shaft 1 is movably inserted in the center line direction. Reference numeral 7 denotes a head cover held at the upper end of the head case 2 so as to be movable in the vertical direction in the figure. Reference numeral 8 denotes a coil spring interposed between the head cover 7 and the upper end of the head case 2. The head cover 7 is urged upward in the drawing by the extension force. Reference numeral 9 denotes an air passage whose center axis is provided at right angles to the center axis of the rotating shaft 1, and the rotating shaft 1 is rotated by air injected from the air passage 9 to the turbine blade 4.

[0003] 10 is a member to be chucked (for example, a cutting tool)
In order to attach and detach the blade 10 (shown by a chain line) to and from the chuck member 5, the head cover 7 pushed in against the tension of the coil spring 8 is brought into contact with the opening and closing body 6, and the opening and closing body 6 is assembled together with the head cover 7. When pressed inward and downward, the convex portion 6b of the opening / closing body 6 is pressed into the slit 5b, and the rear portion 5a of the chuck piece 5 is pushed and opened in the radial direction by the inclined surface 6a,
The so-called chuck is opened, and the blade 10 can be inserted and removed. When the force applied to the head cover 7 is removed, the head cover 7 is pushed upward in the drawing by the tension of the coil spring 8 to return to the original position, and the rear portion 5a of the chuck member 5 is restored by the restoring force. Returning to the original position, the so-called chuck is brought into a closed state, and the opening / closing body 6 is pushed upward in the drawing by the restoring force of the rear portion 5a of the chuck member 5 applied to the inclined surface 6a and returns to the original position. The blade 10 is mounted as shown.

FIG. 4 is a perspective view of the chuck member 5 shown in FIG. 3. The chuck member 5 is formed of a cylindrical member as shown, and a pair of slits extending in one direction in one side thereof. 5b, 5b, which are symmetrical, and the chuck pieces 5a, 5a separated by the slits 5b, 5b are opened and closed by the convex portions 6b of the opening / closing body 6 as described above.
When the blades a and 5a are opened, the blade is inserted, and when the blades are closed, the blade is held.

[0005]

However, if the chuck member is repeatedly used many times, the spring force decreases due to elastic fatigue, and further, the root portion of the slit 5b (the portion of 5d) ).

[0006]

In order to solve the above-mentioned problems, the present invention comprises a cylindrical body having a pair of slits in an axial direction, and an opening / closing member is pushed between the slits in an axial direction to form the slit. Opening a pair of chuck pieces formed therebetween and inserting the chucked member, and then having a chuck member configured to retract the opening / closing member so as to clamp the chucked member by the pair of chuck pieces, The chuck member is characterized in that the pair of chuck pieces symmetrically have a slit having a length shorter than the slit.

[0007]

In a chuck member having a pair of slits symmetrically in an axial direction of a cylindrical body and opening and closing a chuck piece formed between the slits to chuck a cutting tool or the like, the chuck piece has a shorter length than the slit. The pair of slits are provided symmetrically to prevent the spring force of the chuck piece from being reduced or broken, and to reduce the opening force of the chuck piece to facilitate the mounting of the member to be chucked. Provided is a chuck mechanism having a large number of support points for supporting members and thus having a small runout.

[0008]

FIG. 1 is a view showing an example of a turbine head to which a chuck mechanism according to the present invention is applied, and FIG. 2 is a perspective view of a chuck member 5 used for the turbine head shown in FIG. 3 and 4 are denoted by the same reference numerals as those in FIGS. 3 and 4, and detailed description thereof will be omitted.

Thus, in the present invention, the chuck member shown in FIG. 4 is improved to the structure shown in FIG. 2, and as shown in the drawing, the chuck member 5 is divided and formed by slits 5b, 5b of the conventional chuck member 5. A pair of slits 5e, 5e shorter than the length of the slits 5b, 5b are provided symmetrically on the chuck pieces 5a, 5a.

In this way, when the opening / closing member is pushed into the slits 5b, a part of the force acting on each chuck piece 5a is released by the slit 5e, so that the opening / closing member can be easily replaced with each other. The opening of the chuck piece is made smaller (the displacement amount is made smaller) and the chuck piece can be pushed in with a smaller force, and the mounting operation of the member to be chucked (a cutting tool in the illustrated example) can be performed easily. The member to be chucked is each chuck piece (in the case of this embodiment, each chuck piece 5
a, 5a are separated by the slits 5e, 5e, so that the slits 5e, 5e form four pieces), so that the members to be chucked can be mounted more reliably and with less runout. it can.

[0011]

As described above, according to the present invention, the chuck member 5 has a pair of slits symmetrical in the cylindrical axial direction, and the chuck piece formed between the slits is shorter than the slits. Since the pair of slits are provided symmetrically, a decrease in the spring force of the chuck piece can be prevented by a short displacement amount, and breakage of the chuck piece can be prevented.

Further, according to the present invention, since the slits are provided in each chuck piece, the force acting on each chuck piece can be dispersed to reduce the force at the time of pushing the opening / closing body to open the chuck piece. In addition, the chuck operation (mounting operation) becomes easier. Further, according to the present invention, since the member to be chucked (the cutting tool in the case of the illustrated example) is supported at eight points (four points in the prior art), it can be supported with less runout. In addition, even if there is a processing error, since it is evenly distributed to eight places, alignment can be performed accurately.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a turbine head to which a chuck mechanism according to the present invention is applied.

FIG. 2 is a perspective view showing an example of a chuck member used in the chuck mechanism according to the present invention.

FIG. 3 is a view for explaining an example of a turbine head using a conventional chuck mechanism.

FIG. 4 is a perspective view showing an example of a chuck member used in a conventional chuck mechanism.

[Explanation of symbols]

1 ... rotating shaft, 2 ... head case, 3 ... bearing, 4 ...
Turbine blade, 5 chuck member, 6 opening / closing body, 7 head cover, 8 spring, 9 air path, 10 blade tool,
5a: chuck piece, 5b: slit, 5c: tubular part, 5
d: base of slit, 5e: slit, 5f: support.

Claims (1)

(57) [Claims] An opening / closing member is axially inserted between said slits to open and close a pair of chuck pieces formed between said slits, thereby forming a member to be chucked. Inserting, then, having a chuck member to retract the opening and closing member to clamp the member to be chucked by the pair of chuck pieces, wherein the chuck member has a length shorter than the slit in the pair of chuck pieces. A chuck mechanism having symmetrical slits.