JPH11285503A - Chuck mechanism for dental handpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cutting bar from being pulled out from a handpiece in the middle of dental treatment by allowing a chuck piece to bite into the cutting bar during rotation. SOLUTION: A rotary cylinder 20 is freely rotatably held within a head case 10. A chuck cylinder 30 is provided at the inner wall of the cylinder 20 and a spring 41 and a sleeve for opening and closing a chuck 42 are provided in a gap between the cylinders 30 and 20. At the time of pressing down a lid member 13, the sleeve 42 is pressed down to disengage the slope M of the chuck barrel 32 and the slope N of the sleeve 42 from each other to bite-fix the cutting bar to the cylinder 30. When a load is added to the cutting bar during rotation, arcuate strips divided by a slit 33 allow their tip parts, which are opposed to a cutting bar on the tip side of a rotating direction, to bite into the cutting bar to strongly bite-fix.

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 a dental handpiece, and more particularly, to a handpiece such as a micro engine or an air turbine used for dental treatment, wherein a cutting bar is moved from the handpiece during dental treatment. The present invention relates to a chuck mechanism for a dental handpiece, which can be held without falling off.

[0002]

2. Description of the Related Art In dental treatment, as is well known, handpieces such as a micro engine and an air turbine are used to cut teeth. In these handpieces, a bar (not shown) for cutting teeth is used. The blade can be detachably attached to the head of the handpiece.

[0003]

As is well known, a chuck mechanism is used to mount the cutting bar. However, in dental treatment, the cutting bar is rotated at a high speed in the oral cavity of a patient, so that the dental bar is used. It is very dangerous if the cutting bar comes off the chuck mechanism during treatment.

[0004] The present invention has been made in view of the above situation, and particularly, in a dental treatment handpiece,
During rotation, make the chuck piece bite into the cutting bar,
It is an object of the present invention to provide a chuck mechanism in which a cutting bar falls off from a handpiece during dental treatment.

[0005]

According to a first aspect of the present invention, there is provided a rotary cylinder rotatably disposed in a head case, a bearing for rotatably holding the rotary cylinder, and a rotary cylinder having a diameter smaller than the inner diameter of the rotary shaft. A plurality of arc-shaped strips having a small outer diameter, divided by several slits extending from one end, and formed so that the outer diameter gradually increases on the end side, At the other end, a chuck cylinder fixed to the inner wall of the rotary cylinder, a spring inserted into a gap between the chuck cylinder and the rotary cylinder, and a spring inserted into the gap, one end of the spring , A chuck opening / closing sleeve whose inner diameter gradually increases toward the other end, one end of which engages with the other end of the sleeve, the other end of which extends beyond the rotary cylinder, and the end of which is the head. A push member extending to the lid member of the case, When the cover member is pressed down, the chuck opening / closing sleeve is pressed down via the pressing member to release the engagement between the chuck cylinder and the chuck opening / closing sleeve so that the cutting bar is engaged with the chuck cylinder. The present invention is characterized by a chuck mechanism for a dental handpiece described above.

According to a second aspect of the present invention, in the first aspect of the present invention, the arc-shaped strip is formed in a strip having a tip portion notched in an axial direction, and the outer diameter of the strip is gradually reduced. It is characterized in that it is formed to be large.

According to a third aspect of the present invention, in the second aspect of the present invention, the surface on the rear end side in the rotation direction of the arc-shaped strip is formed to be flush with the surface passing through the center of rotation, and the surface on the front end side in the rotation direction is It is characterized by being formed parallel to a parallel surface.

[0008]

FIG. 1 is a sectional view of a main part (head part) of a dental handpiece to which the present invention is applied.
Although the case of an air turbine handpiece is shown as an example, the rotating cylinder is rotated by blowing air to a turbine blade (air turbine) or rotated by a bevel gear provided on the rotating cylinder ( It can be easily understood that the difference between the present invention and the micro-engine handpiece is applicable to both the air turbine handpiece and the micro-engine handpiece.

In FIG. 1, reference numeral 10 denotes a head case;
Is a rotating cylinder, and the rotating cylinder 20 has bearings 21 and
2, the turbine blades 23 and the like are integrally formed, and the outer races of the bearings 21 and 22 are fixed to the head case 10 by O-rings 11 and 12, respectively. The blades 23 are rotatably supported in the head case 10.

In the rotary cylinder 20, a chuck mechanism for detachably attaching a cutting bar to the rotary cylinder 20 is provided. The chuck mechanism holds the cutting bar, and rotates the cutting bar together with the rotary cylinder 20. To cut teeth.

FIG. 2 is a view for explaining an example of the chuck cylinder 30 mounted in the rotary cylinder 20, and FIG.
FIG. 2 is a sectional view showing a part of the chuck cylinder 30 in a sectional view.
FIG. 2B is a cross-sectional view taken along the line BB of FIG. 2A. Cylindrical part 3
The small-diameter cylindrical portion 32 has several slits 33 extending in the axial direction, whereby the small-diameter cylindrical portion 32 has several slits extending in the axial direction (4 in the illustrated example). ) Are divided into strips 32 (32a, 32b, 32c, 32d).

Each of the strips 32 (32a to 32d) has its leading end portion cut out in the axial direction to form a strip 32 '(32a', 3).
2b ', 32c', 32d '), and
Each of the strips 32a 'to 32d' is inclined M toward the tip so that the outer diameter gradually increases.

The small diameter portion 32 of the rotary cylinder 20 and the chuck cylinder 30
, A chuck opening / closing sleeve 42 having an inclined surface N that engages with the inclined surface of the chuck cylinder distal end portion is provided. Are provided with chuck pressing members 43 in order.

In the handpiece as described above, in order to attach the cutting bar to the chuck mechanism, first, the upper cover 13 of the head case 10 is pressed down against the spring 14, and the chuck pressing member 43 is pressed down by the upper cover 13. Therefore, the chuck opening / closing sleeve 42 is pushed down, and the inner peripheral inclined surface N of the chuck opening / closing sleeve 42 and the small pieces 32 ′ (32 a ′ to 32
The outer peripheral inclined surface M of d ') is separated, and a gap is formed between these inclined surfaces, so that a cutting bar can be inserted into the chuck cylinder 30.

As described above, after the cutting tool is inserted into the chuck cylinder 30 and the pressing force applied to the upper lid 13 is released, the chuck opening / closing sleeve 42
And again, the inclined surface M of the chuck cylinder 30
And the inclined surface N of the chuck opening / closing sleeve 42 engages to bite the cutting bar with the strip 32 ′ of the chuck cylinder 30, whereby the cutting bar is integrally attached to the rotary cylinder 20.

FIG. 3 is a view when the cutting bar 50 is engaged by using the chuck mechanism according to the present invention (only the chuck opening / closing sleeve 42 and the cutting bar 50 are shown in a sectional view). Rotate in the direction of arrow S. In the arc-shaped piece (strip 32 or strip 32 ') that bites the cutting bar 50, the rear end face A in the rotation direction is the rotation center O.
, And the front end face B is formed in a plane parallel to the plane A. Therefore, when a load is applied to the cutting bar 50, the rotation of the cutting bar 50 is delayed with respect to the rotation of the chuck opening / closing sleeve 42, and the chuck piece 32 (or 3) is rotated.
2 ') is a direction opposite to the rotation direction, for example, if the chuck strip 32d' is described, the strip 32d 'moves in the direction of the arrow T, and the cutting bar side tip B of the tip face B of the strip 32d'. ′ Bites into the cutting bar 50, the tip B ′ of the strip 32d ′ rotates in the U direction, and the tip A ′ of the rear end face A on the side of the chuck opening / closing sleeve 42
Between the points B 'and A', the strip 32d '
Is twisted, which causes the cutting bar 50
Are more firmly bitten.

As described above, according to the present invention, the portion B 'of the chuck piece (the strip 32 or the strip 32') facing the cutting bar 50 in the tip end surface B in the rotation direction is bitten into the cutting bar 50. Thus, when a load is applied to the cutting bar 50, the chuck piece bites into the cutting bar to prevent the cutting bar from falling off. As one means for that, an example in which the surface A and the surface B are made parallel to each other is described. Although shown, by making the surface of the chuck piece 32 'in contact with the cutting bar 50 an appropriate size, for example, the angle θ at which the chuck piece sandwiches the surface in contact with the cutting bar is set to about 30 to 45 °. Good.

In the embodiment described above, the number of slits is four and the number of strips is four. However, the number of slits is three, and three strips are used. The number is not limited to the illustrated example. Furthermore, each strip 32
The example in which the tip of is formed in the strip 32 'is shown,
It can be easily understood that the strip does not necessarily need to be formed into a strip, and the tip of each strip may have an acute angle as described above.

FIG. 4 is a structural view of a main part for explaining another embodiment of the present invention. In this embodiment, each chuck piece 32 'is shown.
Unlike the embodiment shown in FIG. 3, the position of the slit 33 is provided on the rear side of the chuck strip 32 ', but in this embodiment, the reason is exactly the same as that of the embodiment shown in FIG. As a result, the point B 'bites into the cutting bar to increase the holding force on the cutting bar. FIG.
When the chuck mechanism according to the present invention is used (curve A),
FIG. 9 is a diagram showing an experimental result when a conventional chuck mechanism is used (curve B).

[0020]

As is apparent from the above description, according to the present invention, it is possible to more reliably hold the cutting bar in the dental handpiece, and the cutting bar falls off from the handpiece during dental treatment. I can concentrate on the treatment without worry.

[Brief description of the drawings]

FIG. 1 is a view for explaining an example of a main part (head part) of a dental handpiece to which the present invention is applied.

FIG. 2 is a view for explaining a main configuration of a chuck mechanism according to the present invention.

FIG. 3 is a view for explaining the operation of the chuck mechanism according to the present invention.

FIG. 4 is a view for explaining another operation of the chuck mechanism according to the present invention.

FIG. 5 is a diagram showing a comparison experiment result between a case where the chuck mechanism according to the present invention is used and a case where a conventional chuck mechanism is used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Head case, 11, 12 ... O-ring, 13 ... Upper lid, 14 ... Spring, 20 ... Rotating cylinder, 21, 22 ... Bearing, 23 ... Turbine blade, 30 ... Chuck cylinder, 3
DESCRIPTION OF SYMBOLS 1 ... End part fitted to the rotating cylinder of a chuck cylinder, 32 ... Small diameter part of a chuck cylinder, 32 "... Chuck pieces, 32a-32d
... Strip, 32a 'to 32d' ... Strip, 33 ... Slit, 41 ... Spring, 42 ... Chuck opening / closing sleeve,
43: chuck pressing member, 50: cutting bar.

Claims (3)

[Claims] 1. A rotary cylinder rotatably disposed in a head case, a bearing rotatably holding the rotary cylinder, an outer diameter smaller than an inner diameter of the rotary shaft, and one end portion A plurality of arc-shaped strips that are divided by several slits extending from and that are formed so that the outer diameter gradually increases on the end side, and at the other end, the inner wall of the rotary cylinder A chuck cylinder fixed to the spring, a spring inserted into a gap between the chuck cylinder and the rotary cylinder,
A chuck opening / closing sleeve that is inserted into the gap, one end of which contacts the spring, and whose inner diameter gradually increases toward the other end; one end engages with the other end of the sleeve; And a pushing member having an end extending to the cover member of the head case, and when the cover member is pressed, the chuck opening / closing sleeve is pressed via the pressing member to press the chuck. A chuck mechanism for a dental handpiece in which a cylinder is disengaged from a chuck opening / closing sleeve and a cutting bar is engaged with the chuck cylinder. 2. The arc-shaped strip is formed in a strip having a tip portion cut out in the axial direction, and is formed so that an outer diameter of the strip gradually increases. The chuck mechanism for a dental handpiece according to claim 1, wherein 3. A surface on the rear end side in the rotation direction of the arc-shaped strip is formed to be flush with a surface passing through the center of rotation, and a surface on the front end side in the rotation direction is formed parallel to the parallel surface. The chuck mechanism for a dental handpiece according to claim 2, wherein: