JP2003325550A - Dental cutting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dental cutting apparatus from which a cutting tool can be removed without requiring large force. <P>SOLUTION: The dental cutting apparatus comprises rotary cylinders 17 and 18 to which the cutting tool can be inserted. A chuck 19 arranged inside the rotary cylinder is positioned at an engaging position where attaching and detaching of the cutting tool is made to be impossible by engaging it with the cutting tool inserted to the rotary cylinders and at a non-engaging position where attaching and detaching of the cutting tool is made to be possible without engaging it with the cutting tool inserted to the rotary cylinders. A cylindrical spring 20 being an elastic body keeps the chuck at an engaging position in an operating state and keeps the chuck at a non-engaging position in a non- operating state. A regulation part 23 regulates movement in the inserting direction of the cutting tool at the deepest inserting position of the cutting tool in the rotary cylinders. Then, a slider 21 which is a releasing part switches the elastic body from an operation position to a non-operation position or from the non-operation position to the operation position without interfering with the cutting tool inserted to the inside of the rotary cylinders when the cutting tool is in the deepest inserting position. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental cutting device used for dental treatment.

[0002]

2. Description of the Related Art FIG. 6 is an enlarged sectional view of a conventional dental cutting device, particularly a head portion. In the dental cutting device shown in this figure, upper and lower bearings 102 and 103 and these bearings 102 and 103 are provided inside a general bowl-shaped housing 101.
A rotor 104 rotatably supported by is housed therein. The rotor 104 includes an outer rotary cylinder 106 holding an impeller 105 and an inner rotary cylinder 107 holding a cutting tool A ′.
The outer rotary cylinder 106 and the inner rotary cylinder 1 are equipped with
07 are integrally connected. The inner rotary cylinder 107 is
It has a plurality of chucks 109 arranged at equal intervals in the circumferential direction around a central axis (rotational axis) 108. on the other hand,
Outside the plurality of chucks 109, the chucks 10
A cylindrical spring 110, which is formed so as to be expandable and contractable in the central axis direction by forming a circumferential groove in the metal cylinder, is arranged between 9 and the outer rotary cylinder 106 so as to surround the plurality of chucks 109. Has been done. The tubular spring 110 is not compressed in the central axis direction (uncompressed state) as shown in the figure.
Then, the plurality of chucks 109 are biased from the outer side to the inner side in the circumferential direction to be engaged with the outer peripheral surface of the cutting tool A ′.
On the other hand, in the state of being compressed in the central axis direction (compressed state),
The plurality of chucks 109 are released from the cylindrical spring 110 and move in the direction away from the central axis by the elastic restoring force of the chucks themselves, thereby permitting the attachment / detachment of the cutting tool A ′.
In order to switch the tubular spring 110 from the non-compressed state to the compressed state, a tubular member (slider 11
1) is arranged. The slider 111 has a lowered position in which the slider 111 comes into contact with the upper end of the cylindrical spring 110 by a restricting portion 112 fixed to the inner upper end of the outer rotary cylinder 106,
The cylindrical spring 110 can be moved between a raised position separated from the upper end by a predetermined distance. A push button 112 or a push cap is provided on the upper part of the housing 101 so that the cylindrical spring 110 can be switched from the non-compressed state to the compressed state or from the compressed state to the non-compressed state via the slider 111 as needed. Is provided so as to be movable in the central axis direction. Further, the push button 112 is biased to the raised position by a spring 113 arranged inside thereof.

According to the cutting device having such a configuration, when the push button 112 is pressed against the biasing force of the spring 113 from the state shown in the figure, the push button 11 is pressed.
The bottom of 2 contacts the upper end of the slider 111. Next, when the push button 112 is further pushed, as shown in FIG. 7, the slider 111 compresses the cylindrical spring 110 in contact with the lower end thereof to switch to the compressed state. This allows
The plurality of chucks 109 move in a direction away from the central axis to separate from the cutting tool A ′, and the cutting tool A ′ can be removed. On the contrary, when the cutting tool A ′ is attached to the cutting device, the push button 112 is pressed with the cutting tool A ′ not completely inserted, and the cylindrical spring 110 is switched to the compressed state via the slider 111. In this state, insert the cutting tool A'to the deepest part and push the push button 112.
To release. As a result, the cylindrical spring 110 returns to the non-compressed state, the plurality of chucks 109 move toward the central axis, and engage with the outer peripheral surface of the cutting tool A ′.

[0004]

However, in the cutting device thus constructed, as shown in FIGS.
The insertion end of the inserted cutting tool A ′ is brought into contact with the slider 111 to regulate it. Further, as shown in FIG. 6, when the tubular spring 110 is in the non-compressed state, the slider 111 can only descend to the position (see FIG. 8) in contact with the restriction portion 112. On the other hand, as shown in FIG.
The descending position of the slider 111 when the cylindrical spring 110 is compressed is further below the position shown in FIG. Therefore, when the compressed state of FIG. 7 is returned to the non-compressed state of FIG. 6, the ascending / descending range 114 of the slider 111 (see FIG. 6) is smaller than the ascending / descending range 116 of the cutting tool A ′. Therefore, when the cutting tool moves to the deepest part of the ascendable / descendable range 116 due to the axial force received during cutting (see FIG. 8) despite being held by the chuck 109, the push button 112 is pushed from this state. In order to push and compress the cylindrical spring 110 via the slider 111, the cutting tool A ′ engaged with the chuck 109 is pressed.
Must be pushed down together with the slider 111.
However, it is not easy to push down the cutting tool A ′ engaged with the chuck 109, and even if it is possible to push it down, a considerably large force is required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional cutting device as described above. An engaging position that is arranged inside the cylinder and that engages with the cutting tool inserted into the rotary cylinder to make it impossible to attach and detach the cutting tool, and attach and detach the cutting tool without engaging the cutting tool. A chuck that can take a non-engaging position that enables the chuck, an elastic body that keeps the chuck in the engaging position in the operating state and releases the chuck to the non-engaging position in the non-operating state, and cutting in the rotary cylinder. A restriction portion that restricts movement of the cutting tool in the insertion direction at the deepest insertion position of the tool, and when the cutting tool is at the deepest insertion position, without interfering with the cutting tool inserted in the rotary cylinder, Above elasticity To the non-operating position from the operating position, also characterized in that a release unit for switching to the operating position from the non-operating position.

In the dental cutting device according to another aspect of the present invention, the releasing portion is located closer to the cutting tool insertion port of the rotary cylinder than the regulating portion and faces the elastic body, and the regulating portion. A slider that has a protruding portion that protrudes to the opposite side of the cutting tool insertion port beyond the portion, and is movably provided in the direction of the central axis in the rotating cylinder; and a button that faces the protruding portion of the slider. , A spring for holding the button at a position apart from the protruding portion, and pressing the button against the biasing force of the spring causes the button to contact the protruding portion of the slider, and the button Is further in contact with the protruding portion of the slider, and the elastic body is switched from the operating state to the non-operating state by further pressing the button.

In the dental cutting device according to another aspect of the present invention, the slider is in a non-contact position where the slider comes into contact with the elastic body in the operating state and is separated from the elastic body in the operating state without contacting the elastic body. The slider is held so as to be movable between the position and the position, and the slider at the non-contact position is restricted from moving in the direction away from the elastic body by the restricting portion.

In the dental cutting device according to another aspect of the present invention, the regulating portion has an end portion on the cutting tool insertion port side that is in contact with the cutting tool and is located at a contact point for regulating the cutting tool. , The cutting tool insertion port side.

In the dental cutting device according to another aspect of the present invention, the restriction portion is formed as a separate component from the rotary cylinder, and is provided on the rotary cylinder in a state of not moving toward the cutting tool insertion opening. It is characterized by being.

In the dental cutting device according to another aspect of the present invention, the restriction portion includes an annular tubular portion and a projection portion that projects radially inward from the annular tubular portion. The movement of the cutting tool in the insertion direction is restricted.

In a dental cutting device according to another aspect of the present invention, the restriction portion is disposed on a fixed ring fixed to the rotary cylinder and a cutting tool insertion port side of the fixed ring, and the center of the rotary cylinder is provided. And a movable ring disposed so as to be movable in the axial direction, the movable ring having a protrusion protruding inward in the radial direction, and the protrusion restricts movement of the cutting tool in the insertion direction. It is characterized by being done.

In the dental cutting device according to another aspect of the present invention, the protrusions are symmetrical with respect to the central axis of the rotary cylinder.
It is characterized in that the two projecting portions are connected to each other to form a bridge portion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A plurality of forms of a dental cutting device according to the present invention will be described below with reference to the accompanying drawings. In addition,
Portions and members indicated by the same reference numerals in a plurality of drawings indicate the same or similar portions.

Embodiment 1 FIG. 1 is an enlarged view of a head portion of a handpiece which is a dental cutting device according to the present invention. As shown in the figure, the head portion 1 has a housing 2 that accommodates a bearing mechanism and the like described later.

The housing 2 is a bowl-shaped outer housing 3, a bowl-shaped inner housing 4 which is detachably mounted inside the outer housing 3, and an annular top housing which is mounted in an upper opening of the inner housing 4. 5, and an empty space 6 is formed inside the inner housing 4 and the top housing 5. An upper bearing portion 7 and a lower bearing portion 8 are arranged above and below the empty space 6, and are held by the top housing 5 and the inner housing 4, respectively. The upper bearing portion 7 and the lower bearing portion 8 rotatably support the rotor 10 arranged coaxially with the central axis 9 of the housing 2.

The rotor 10 includes an impeller 11 arranged between the upper bearing portion 7 and the lower bearing portion 8. Wing wheel 11
Has an upper blade portion 12 formed on the upper outer periphery and a lower blade portion 13 formed on the lower outer periphery. Although the configuration of the impeller 11 will not be described in detail in this specification, the two-stage impeller disclosed in Japanese Patent Laid-Open No. 2001-162416 can be suitably used for the impeller 11. On the other hand, an air supply passage 14 is formed in the inner housing 4 facing the upper blade portion 12. Further, an exhaust passage 15 is formed in the inner housing 4 facing the lower blade portion 13. Then, on the inner surface of the inner housing 4,
An air passage 16 is fluidly connected to the upper blade portion 12 and the lower blade portion 13, respectively.

The rotor 10 also has an outer rotary cylinder 17 which holds an impeller 11. An inner rotary cylinder 18 is fitted inside the outer rotary cylinder 17. A portion of the inner rotary cylinder 18 within a predetermined range from the lower end is fixed to the outer rotary cylinder 17, and a portion above the outer rotary cylinder 17 has a smaller diameter. In addition, a plurality of chucks 19 are formed between these slits by forming a plurality of slits that extend in a direction parallel to the central axis 9 at equal intervals in the circumferential direction of the central axis 9 in the reduced diameter portion. The chucks 19 are deformed outward in the radial direction. Further, in the annular space formed between the smaller diameter portion of the inner rotary cylinder 18 and the outer rotary cylinder 17, a tubular spring 20 that is expandable and contractible in the central axis direction is arranged, and the tubular spring 20 extends. In a normal state (operating state), the inner surface of the upper end of the tubular spring 20 comes into contact with the outer surface of each chuck 19 to urge the chuck 19 toward the central shaft 9, and as shown in the figure, The cutting tool A is held by being engaged with the outer peripheral surface of the columnar cutting tool A inserted from the lower end opening.

In order to release the engagement between the chuck 19 and the cutting tool A, a slider 21 of a cylindrical ring which constitutes a releasing portion is arranged on the cylindrical spring 20, and the lower end surface of the slider 21. Is in contact with the upper end surface of the tubular spring 20. The slider 21 also has a long hole (through hole) 22 penetrating in a direction orthogonal to the central axis 9 and extending in the central axis direction. On the other hand, the outer rotary cylinder 17 is fixed with a restricting portion 23 that passes through two holes formed in the outer rotary cylinder 17 and extends in a direction orthogonal to the central axis 9. It penetrates the long hole 22.
As shown in FIG. 1, the size of the restriction portion 23, particularly the dimension in the central axis direction, is such that the slider 21 is at the highest position.
The gap 25 in the central axis direction formed between the slider 21 and the restriction portion 23, that is, the gap formed between the slider 21 and the restriction portion 23 at the portion of the elongated hole 22 is then the tubular shape of the slider 21. It is formed larger than the gap 25 formed between the spring 20 and the spring 20. Therefore, the slider 21 descends from the state shown in FIG. 1 and contacts the cylindrical spring 20 without interfering with the attached cutting tool A, and further compresses the cylindrical spring 20 to disengage the chuck 19. It can be returned to the engagement position.

Further, in the present embodiment, the regulating portion 23
A trapezoidal depression 26 is formed on the lower surface of the cutting tool 26, and a curved surface portion (chamfered portion) 28 on the outer periphery of the upper end of the cutting tool A contacts the hypotenuse portion 27 of the trapezoidal depression 26.

A push button type release mechanism (release unit) 29 for contracting the tubular spring 20 in cooperation with the slider 21.
Has a support ring (annular member) 30. The support ring 30 is exteriorly mounted on the annular top housing 5, and is fixed by a fixing ring 31 fixed to the upper end of the outer housing 3. Further, the cap-shaped push button 32 for pressing the slider 21 is provided with the support ring 30.
It is supported by the spring 33 so as to be movable by a predetermined distance in the direction of the central axis, and is held at the highest position farthest from the slider 21 by a spring 33 arranged inside.

According to the handpiece 1 having the above structure, the high pressure air supplied through the air supply passage 14 of the inner housing 4 is applied to the upper blade portion 12 of the impeller 11. The high-pressure air that hits the upper blade portion 12 is applied to the lower blade portion 13 via the air passage 16. As a result, the impeller 11 is rotated, and the rotor 10 including the impeller 11 and the cutting tool A held by the rotor 10 rotate. On the other hand, the high-pressure air hitting the lower blade portion 13 is discharged to the outside via the exhaust passage 15.

When exchanging the cutting tool A according to the content of treatment, the push button 32 is pushed downward against the biasing force of the spring 33. This allows the push button 32
Contact the slider 21. From this state, a pressing force is further applied to the push button 32, and the slider 21 is pressed down against the cylindrical spring 20. At this time, the slider 21 moves without interfering with the cutting tool A. As a result, the tubular spring 20 contracts in the central axis direction (the state of the tubular spring 20 at this time is referred to as “non-operating state”). Then, the plurality of chucks 19 move outward due to their own elastic return force and disengage from the cutting tool A, enabling the cutting tool A to be detached (the position of the chucks 19 at this time is “non-related”). "Match position".).

When the cutting tool A is attached, the push button 32 is pressed downward against the urging force of the spring 33 to urge the slider 21 and the cylindrical spring 20 to keep the plurality of chucks in the disengaged position. , Cutting tool A in this state
Is inserted into the inner rotary cylinder 18, and the push button 32 is released at the position where the insertion side end of the cutting tool A hits the restriction portion 23 (the deepest insertion position). As a result, the tubular spring 20 moves toward the central axis 9 and engages with the outer peripheral surface of the inserted cutting tool A to hold the cutting tool A.

When the cutting tool A is not in the deepest insertion position and is held by the chuck 19 in front of it with the cutting tool A attached, the cutting tool A is pushed to the deepest insertion position by the force received during the subsequent cutting. Sometimes. However, as described above, the size of the elongated hole 22 formed in the slider 21 in the central axis direction is determined by the restriction portion 23 in that direction.
The gap 25 in the central axis direction formed between the slider 21 and the restricting portion 23 is much larger than the size of the slider 21 and between the slider 21 in the highest position and the cylindrical spring 20 in the operating position. Since the gap 25 is larger than the gap 25 formed in, the cylindrical spring 20 can be switched from the operating position to the non-operating position by receiving the resistance from the cutting tool A by pressing the push button 32.

Further, in the present embodiment, the curved portion (chamfered portion) 28 on the outer periphery of the upper end of the cutting tool A is abutted and regulated by the oblique side portion 27 of the trapezoidal recess 26 formed on the lower surface of the regulation portion 23. Therefore, the position where the cutting tool A is restricted is above the end surface of the lower end surface (cutting tool insertion port side) of the restriction portion 23. Therefore, the insertion amount of the cutting tool A can be made larger than that in which the cutting tool is restricted by a simple rod-shaped restricting portion. Therefore, since the length of the portion where the cutting tool A projects from the head portion 1 can be shortened, there is an advantage that treatment in a narrow oral cavity becomes easy.

Second Embodiment: FIGS. 2 and 3 show a dental cutting device according to a second embodiment. In this cutting device, the restricting portion 40 integrally includes an annular ring 41 and a pair of protruding portions 42 that symmetrically protrude from the vicinity of the middle stage of the inner surface of the annular ring 41 toward the central axis 9, as shown in FIG.
As shown in (a), it is fixed to the upper end of the outer rotary cylinder 17. On the other hand, the slider 43 includes a tubular portion 44 arranged between the tubular spring 20 and the regulating portion 23, and an upward projecting portion that passes from the tubular portion 44 to the side of the protruding portion 42 and projects above the regulating portion 23. It is equipped with 45. Also, push button 3
A boss portion 46 that faces the upper protruding portion 45 of the slider 21 is formed in the center of the bottom surface of the slider 2.

In such a structure, the slider cylinder portion 4
4 has a length in the direction of the central axis of the cylindrical spring 20 in the operating position.
The distance between the cylindrical spring 20 and the restriction portion 23 is shorter than the predetermined distance (the gap 4
Only 7) can be moved up and down. Also,
The upper protruding portion 45 is configured to protrude upward from the regulating portion 23 by a predetermined length 48 in a state where the lower end portion of the slider 21 is in contact with the cylindrical spring 20 in the operating position. Therefore, as shown in the drawing, even when the cutting tool A is at the deepest insertion position where it contacts the regulating portion 23, by pushing the push button 32, the slider 21 is lowered without interfering with the cutting tool A, and the tubular spring 20 is pressed. Can be switched from the operating position to the non-operating position, and the chuck 19 can be switched from the engaging position to the non-engaging position.

Further, as in the first embodiment, the insertion of the cutting tool A is restricted by the pair of protrusions 42 which symmetrically protrude from the vicinity of the middle stage of the inner surface of the annular ring 41 toward the central axis 9. The point that regulates the cutting tool A is the annular ring 41.
Above the lower end (the end on the cutting tool insertion side). Therefore, the insertion amount of the cutting tool A can be made larger than that when the cutting tool is restricted by a simple rod-shaped restricting portion. And
Since the length of the portion where the cutting tool A projects from the head portion 1 can be shortened, there is an advantage that treatment in a narrow oral cavity becomes easy.

Third Embodiment: FIGS. 4 and 5 show a dental cutting device according to a second embodiment. In this cutting device, the restriction portion 50 includes a lower ring (movable ring or movable annular tubular portion) 51 and an upper ring (fixed ring or fixed annular tubular portion) 52. The lower ring 51 is provided with a bridge portion 53 protruding upward from the upper end of the lower ring 51 and extending in a direction orthogonal to the central axis 9, which is the pair of protrusion portions described in the second embodiment. Are formed in a connected form. On the other hand, the upper ring 52 is provided with a recess 54 at the lower end facing the lower ring 51, the recess 54 having a shape into which the bridge 53 is just fitted. Further, the slider 55 includes a tubular portion 56 arranged between the tubular spring 20 and the regulating portion 23, and an upward projecting portion 57 projecting from the tubular portion 56 to both sides of the bridge 53 and above the bridge 53. Is equipped with.

These parts are assembled inside the outer rotary cylinder 17. Specifically, first, the upper ring 5
2 is arranged at the upper end of the outer rotary cylinder 17 with the recess 54 facing downward (cutting tool insertion port), and is fixed by spot welding or the like. Next, a processing jig (for example, a mandrel for improving polishing accuracy) is inserted and fixed to the upper ring 5.
Process 2. At this time, since only the upper ring 52 is inserted into the outer rotary cylinder 17, the processing using the processing jig can be performed accurately without being disturbed by anything. Next, the lower end of the outer rotary cylinder 17 (the end on the cutting tool insertion port side)
Insert the lower ring 51 from the upper bridge 53
Is inserted into the lower end recess 54 of the upper ring 52. afterwards,
The slider 55 is inserted, and its upper protruding portions 57 pass through both sides of the bridge 53 and are projected upward. Finally, the inner rotary cylinder 18 that covers the tubular spring 20 is inserted into the outer rotary cylinder 17, and the inner rotary cylinder 18 is fixed by spot welding or the like.

As described above, the restricting portion 50 includes the lower ring 5
Since it is composed of two members, 1 and the upper ring 52, the polishing work by the processing jig can be accurately performed as described above. Therefore, when the machining accuracy is low, the cutting tool A inserted into the inner rotary cylinder 18 generates vibration during rotary cutting, which shortens the life of the bearings 7 and 8 and increases noise. However, such a problem does not occur for the above reason. Further, when the push button 32 is pushed, the push button 32 does not receive a reaction force from the lower ring 51, so that the resistance when opening the chuck 19 can be minimized.

In such a structure, the slider cylinder portion 5
The length of 6 in the direction of the central axis is the cylindrical spring 20 in the operating position.
The distance between the cylindrical spring 20 and the restriction portion 23 is shorter than the predetermined distance (the gap 5
Only 8) can be moved up and down. Also,
The upper protruding portion 58 is configured to protrude upward from the regulating portion 23 by a predetermined length 59 in a state where the lower end portion of the slider 21 is in contact with the tubular spring 20 in the operating position. Therefore, as shown in the drawing, even when the cutting tool A is at the deepest insertion position where it contacts the regulating portion 23, by pushing the push button 32, the slider 21 is lowered without interfering with the cutting tool A, and the tubular spring 20 is pressed. Can be switched from the operating position to the non-operating position, and the chuck 19 can be switched from the engaging position to the non-engaging position.

Further, as in the first and second embodiments, since the bridge 53 that contacts the cutting tool A and restricts its insertion is formed on the upper part of the lower ring 51, the cutting tool is simply a bar-shaped restricting portion. Cutting tool A rather than regulating
The insertion amount of can be made large. As a result, since the length of the portion where the cutting tool A projects from the head portion 1 can be shortened, there is an advantage that treatment in a narrow oral cavity becomes easy.

[0034]

As is apparent from the above description, according to the dental cutting device of the present invention, even if the cutting tool is moved to the deepest insertion position by the force received during cutting, the releasing part causes the cutting tool to work. Even at the deepest insertion position, the elastic body can be switched from the operating position to the non-operating position without interfering with the cutting tool. Therefore, the releasing portion can be easily operated without requiring a large force.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a dental cutting device according to a first embodiment.

FIG. 2 is a partially enlarged sectional view of a dental cutting device according to a second embodiment [FIG. 2 (a)] and an axial end view of a restricting portion and a slider [FIG. 2 (b)].

FIG. 3 is a perspective view of the restriction portion shown in FIG.

FIG. 4 is a partially enlarged sectional view of a dental cutting device according to a third embodiment.

FIG. 5 is a perspective view of a restriction portion and a slider shown in FIG.

FIG. 6 is a partially enlarged sectional view of a conventional cutting device.

FIG. 7 is a sectional view for explaining the cutting device shown in FIG.

8 is a cross-sectional view for explaining the cutting device shown in FIG.

[Explanation of symbols]

A: Cutting tool 1: Head 2: Housing 10: rotor 17: Outer rotary cylinder 18: Inner rotating cylinder 19: Chuck 20: Cylindrical spring 21: Slider 23: Regulatory Department 32: Push button

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tokuyuki Tanaka             680 Higashihamanancho, Fushimi-ku, Kyoto-shi, Kyoto             Morita Manufacturing Co., Ltd. F-term (reference) 4C052 AA06 BB01 CC24 DD01

Claims (8)

[Claims] 1. A rotary cylinder into which a cutting tool can be inserted, and an engagement which is arranged inside the rotary cylinder and which engages with the cutting tool inserted into the rotary cylinder to disable attachment and detachment of the cutting tool. A chuck that can take a position and a non-engaging position that enables the cutting tool to be attached and detached without engaging the cutting tool; and a chuck that keeps the chuck in the engaged position in the operating state and holds the chuck in the non-operating state. An elastic body that is released to a non-engaging position, a restriction portion that restricts movement of the cutting tool in the insertion direction at the deepest insertion position of the cutting tool in the rotary cylinder, and the cutting tool is at the deepest insertion position, A dentistry characterized by comprising a releasing portion for switching the elastic body from an operating position to a non-operating position and from the non-operating position to an operating position without interfering with a cutting tool inserted in the rotary cylinder. for Cutting apparatus. 2. The releasing portion includes a facing portion that is closer to the cutting tool insertion opening of the rotary cylinder than the restriction portion and faces the elastic body, and a cutting tool insertion opening that exceeds the restriction portion. A slider that has a protruding portion that protrudes on the opposite side and is provided so as to be movable in the central axis direction inside the rotary cylinder, a button that faces the protruding portion of the slider, and a position that separates the button from the protruding portion. A spring for holding the button in contact with the protruding portion of the slider by pressing the button against the biasing force of the spring, and the button is in contact with the protruding portion of the slider. The dental cutting device according to claim 1, wherein the elastic body is switched from an operating state to a non-operating state by further pressing the button in this state. 3. The slider is movably held between a contact position in contact with the elastic body in the operating state and a non-contact position in which the slider is separated without contacting the elastic body in the operating state. The dental cutting device according to claim 2, wherein the slider in the non-contact position is restricted from moving in a direction away from the elastic body by the restricting portion. 4. The regulating portion is such that an end portion on the cutting tool insertion port side is on the cutting tool insertion port side with respect to a contact point that contacts the cutting tool and regulates the cutting tool. The dental cutting device according to claim 1, wherein the cutting device is for dental use. 5. The regulating portion is configured as a separate component from the rotary cylinder, and is provided on the rotary cylinder so as not to move toward the cutting tool insertion opening. The dental cutting device according to any one of to 4. 6. The restricting portion includes an annular cylindrical portion and a protrusion protruding radially inward from the annular cylindrical portion, and the protrusion restricts movement of the cutting tool in the insertion direction. The dental cutting device according to any one of claims 1 to 5, wherein the cutting device is a dental cutting device. 7. The fixed portion is fixed to the rotary cylinder, and the movable ring is arranged on the cutting tool insertion port side of the fixed ring and is movable in the central axis direction of the rotary cylinder. The movable ring is provided with a protrusion that protrudes inward in the radial direction, and movement of the cutting tool in the insertion direction is restricted by the protrusion. 5
The dental cutting device according to any one of 1. 8. The two protrusions are formed symmetrically with respect to the central axis of the rotary cylinder, and these two protrusions are connected to each other to form a bridge portion. The dental cutting device according to any one of 6 and 7.