JPH0467864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a chuck for a rotary cutting tool such as a dental handpiece.

(Prior Art) In dental treatment using a handpiece, the cutting bur is frequently replaced during treatment depending on the type of treatment. Therefore, in this type of dental handpiece, the cutting bur is detachably attached via chuck means. As such a chuck means, the cutting bar is elastically deformed by an elastic body such as resin, rubber, a coil spring, or a plate spring to elastically grip the cutting bar.
-90609, a friction chuck as disclosed in JP-A No. 52-132593, and a friction chuck by pressure contact between the tapered surfaces of a metal chuck member and a chuck case (rotation drive shaft), for example, as disclosed in JP-A-54-121596, JP-A-Sho. 58
A collet chuck, etc., which clamps and grips the cutting bar by applying a pressing force in the centripetal direction, as disclosed in Japanese Patent Application No. 136117, is employed. The cutting bar can be attached and detached using these chuck means, in the case of a friction chuck, by inserting and removing the cutting bar against the restoring force of the elastic body, and in the case of a collect chuck, by loosely tightening the chuck member against the chuck case. It will be done. On the other hand, in the case of a collect chuck, in addition to the one disclosed in JP-A-54-121596, in which a chuck member is screwed onto the chuck case, and the cutting bar can be removed by unscrewing this, there is also a recent one in JP-A-56-151035. As shown in the figure, the chuck member is pressed against the chuck case by the biasing force of a spring or the like to grip the cutting bar, and when detaching the chuck member, the push cap provided on the back of the head part is pressed against the biasing force of the spring. Types that allow the clamping to be released have also been developed and come into use.

(Problems to be Solved by the Invention) However, the rotary cutting tools that have been manufactured and have the chuck means described above have the following problems. In other words, in the case of a friction chuck, the cutting bar can be attached and detached due to its strong elastic gripping force, and there is no accident of the cutting tool coming out;
It must be performed using a special tool as shown in 65009, and as mentioned above, this causes a lack of smoothness in dental treatment that requires frequent replacement of the cutting bar. In addition, in the case of the screw-on collector chuck mentioned above, a separate tool is required to loosen and tighten it.
There are the same troubles as above. Furthermore, in the case of a push-type collet chuck, since the grip is made by metal-to-metal contact and the contact area is small, if the push cap hits another part during rotation, the chuck will be released unexpectedly and the cutting bar may slip out. This may lead to medical accidents. Therefore, the pressure requires a strong force (5 to 10 kg/cm ² ), which places a burden on the fingers and impedes the treatment.
Although attachment and detachment of the cutting bar to and from the chuck means has the advantage of not requiring attachment/detachment tools, it is not sufficiently safe and reliable, and moreover, it is necessary to change the grip each time when attaching and detaching the cutting bar. This was troublesome and was one of the causes of impairing the smoothness of treatment.

The present invention has been made in view of the above, and it is an object of the present invention to provide a chuck for a new rotary cutting tool that allows the cutting bar to be replaced extremely easily and reliably without changing the grip.

(Means for Solving the Problems) The structure of the present invention for achieving the above object will be explained based on the attached embodiment diagrams. Fig. 1 is a longitudinal sectional view of the head portion of a dental handpiece to which the present invention is applied, Fig. 2 is an exploded perspective view of the chuck portion in the same embodiment, and Fig. 3 is a longitudinal sectional view of another embodiment. , FIG. 4 is an exploded perspective view of the pressure fluid introduction part in the same embodiment,
FIG. 5 is an overall view of the handpiece, FIG. 6 is an operation control circuit diagram, and FIG. 7 is a timing chart thereof. That is, the chuck of the rotary cutting tool of the present invention is
a chuck means 2 which is provided in the cutting bar rotation drive shaft 5 of the tip casing 1 and expands or contracts the inner diameter of the chuck by pressing the rear end in the axial direction of the cutting bar 3 to release or grip the cutting bar 3; A push plate 42 is disposed behind the chuck means 2 in the tip casing 1 and moves or deforms in the axial direction of the cutting bar 3 to press the rear end of the chuck means 2; and means for supplying pressure fluid into the tip casing 1.

The manner in which the cutting bar is gripped and released by the chuck means and the pressure fluid is introduced is as follows: the cutting bar is gripped by the chuck means during the introduction of the pressure fluid and the grip is released when the introduction of the pressure fluid is stopped; It is also possible for the bar to be gripped by the chuck means and to be released from its grip when pressure fluid is introduced, the latter case being shown in both figures. Compressed air, compressed water, compressed oil, or the like is used as the pressure fluid 4, and is introduced into the tip casing 1 through a supply pipe line 41 disposed inside the main body 10 or along its outer periphery.

(Function) In the figure, the cutting bar 3 is normally held integrally with the chuck means 2 and rotates together with the chuck means 2. Then, if you want to replace the cutting bar 3,
When the rotation is stopped and the pressure fluid 4 is introduced into the tip casing 1, the grip on the chuck means 2 is released, and the cutting bar 3 can be easily inserted and removed from the tip. The introduction of this pressure fluid 4
As shown in the figure, this is possible by opening a solenoid valve (not shown) disposed in the middle of the supply pipe 41 by operating a touch switch 44 attached to the peripheral body of the main body 10 near the tip casing 1. Yes, so you don't have to change grips.
Moreover, it can be done extremely easily by fingertip operation without requiring any force.

(Example) Next, an example will be described.

Embodiment 1 The embodiment shown in FIGS. 1 and 2 shows an example of application to an air turbine type dental handpiece, in which a cylindrical rotary drive shaft 5 having an impeller 51 in the tip casing or head portion 1 is used. is rotatably installed inside via bearings 6, 6. The drive shaft 5 also serves as a chuck case, and a chuck means 2 is fitted and integrated into its cylinder, and the cutting bar 3 gripped by the chuck means 2 is used to supply air for the turbine provided in the main body 10. The compressed air supplied from the conduit 50 acts on the impeller 51 so that the impeller 51 integrally rotates, and is used for dental treatment.

The chuck means 2 includes a metal collect chuck 21 having a tapered part 211 whose outer diameter on the distal side is progressively tapered and a slit 212 cut along the axial direction from the distal end, and a metal collect chuck 21 that is fitted into the inner surface of the tapered part 211. It consists of a friction chuck 22 inserted, a compression spring 23 fitted to the rear end circumferential body of the collector chuck 21, and a spring receiver bush 24 screwed to the rear end surface of the collector chuck 21. In this case, the friction chuck 22 is made of hard fluorocarbon rubber that can withstand high temperature sterilization and gas sterilization.
It is preferable to make it from heat-resistant urethane rubber, Teflon resin, etc., and thereby prevent secondary infections such as hepatitis B and AIDS. On the other hand, a tapered portion 52 is formed on the inner surface of the front side of the drive shaft 5, and the inner diameter thereof is tapered in a pre-gradually opening shape.
When the drive shaft 5 is inserted into the drive shaft 5, the tapered portions 211 and 52 of the two correspond to each other. After inserting the chuck means 2 into the drive shaft 5,
The rear end surface of the drive shaft 5 and the jaw portion 24 of the bush 24
When the bush 24 is screwed onto the rear end of the collection chuck 21, the chuck means 2 is elastically biased rearward by the restoring elasticity of the compression spring 23. Due to this elastic bias, the tapered portions 211 and 52 are pressed against each other, so that the drive shaft 5 and the chuck means 2 are integrated, and the tapered portion 211 of the collect chuck 21 is deformed in the centripetal direction, and the tapered portion 211 is attached to the inner surface of the chuck 21. A centripetal pressing force is applied to the friction chuck 22. The inner diameter of the friction chuck 22 is normally slightly smaller than the outer diameter of the cutting bar, so that the cutting bar 3 can be inserted into the friction chuck 22 with a finger, and the cutting bar 3 can be firmly inserted by tightening the collector chuck. The structure is such that it can be held. Therefore, if the cutting bar 3 is inserted into the inner cylinder of the chuck means 2, the cutting bar 3 will be held integrally by the chuck means 2 by this pressing force.
In the figure, reference numeral 25 is a front guide made of hard metal, and 214 and 213 are rear guide parts made of hard metal. It has an inner diameter slightly larger than the outer diameter of the cutting bar 3, and prevents the cutting bar 3 from swinging around due to rotation.

In the state where the cutting bar 3 is gripped by the chuck means 2 as described above, the collection chuck 21
When the rear end surface is pressed forward against the elasticity of the compression spring 23, the collection chuck 21 moves forward, and the mutual pressure between the tapered portions 211 and 52 is relaxed, thereby reducing the gripping force. As a result, the cutting bar 3 can be easily extracted by hand. The gripping and releasing of the chuck means 2 is performed by introducing a pressure fluid 4, which will be described below.

That is, a cap 11 is screwed onto the rear end surface of the head portion 1 via a threaded portion 12.
There is a push plate 42 that slides back and forth in the space 110 of O.
It is airtightly equipped via a ring 421, and the compressed air 4 is introduced from the supply pipe 41 attached to the circumference of the main body 10 through the rear surface of the cap 11 to the rear surface of the push plate 42. being done. Also,
A columnar projection 422 is protruded from the center of the front surface of the push plate 42 and faces the bush 24.
Due to the elastic force of the wave washer 423 interposed in the front side cavity 110 of 2, the push plate 42 is positioned rearward, and the front surface of the projection 422 and the back surface of the bush 24 are separated from each other. When compressed air 4 is introduced in this state, the push plate 42 is pushed forward by the air pressure, and the protrusion 422 is pushed forward by the push plate 42.
The collet chuck 21 is pressed forward against the elasticity of the compression spring 23, and as a result, the grip on the chuck means 2 is released as described above, and the cutting bar 3 can be pulled out. When the cutting bar 3 is replaced in this state and the introduction of the compressed air 4 is stopped, the cutting bar 3 is gripped and integrated with the chuck means 2 by the opposite action to that described above. Note that the wave washer 423 functions to constantly push the push plate 42 backward, but even without it, the pressure of turbine air is applied within the head 1 during use, so the push plate 42 is automatically pushed backward. It will move to the position shown in the figure and come to rest. Further, a recess 42 is provided on the rear surface of the push plate 42.
4, the surface on which the pressure fluid acts is enlarged, and a large pressure can be applied to the press plate 42 even in the initial stage of pressing. Further, in this embodiment, the push plate 42 and the wave washer 423 are constructed as separate members, but they can be constructed as a single unit by using a push plate that deforms under the pressure of a pressure fluid. It is also possible to use an accordion-shaped bellows as the push plate that deforms due to the pressure of the pressure fluid.

As in this embodiment, if a combination of a metal collector chuck 21 and a friction chuck 22 made of an elastic member is used as the chuck means 2, the collector chuck 21 indirectly connects the cutting bar 3 via the friction chuck 21. Since the bar is clamped and gripped, there is less bar deflection and the clamping force is smaller than in the case of gripping directly with a conventional metal collector chuck, resulting in improved operability.
Furthermore, since the friction chuck 22 compresses and grips the cutting bar 3 by exerting a centripetal pressing force from the collection chuck 21 behind it, the inner diameter of the cutting bar 3 is smaller than in the case of a conventional friction chuck. (Incidentally, in the case of conventional friction chucks, the cutting bar is press-fitted and the chuck itself deforms elastically to grip it, so its inner diameter is much larger than the outer diameter of the cutting bar.) ), when the grip is released, the cutting bar can be easily inserted and removed by hand, and there is almost no elastic deformation, so even if the cutting bar 3 is replaced frequently, the friction chuck 22 will not deteriorate over time. This improves durability.

In addition, in the illustrated example, the rear guide portion 213 of the collection chuck 21 (the part where the compression spring 23 is fitted)
The outer diameter of the central portion 214 is smaller than that of the central portion 214, and the boundary between the two different diameter portions is a diameter-reduced stepped portion 215, while an inward flange portion 53 is formed at the rear end of the drive shaft 5. The abutment of the diameter-reducing step portion 215 against the inward flange portion 53 prevents the collection chuck 21 from moving back excessively. Therefore, the tip of the collet chuck 21 is not excessively deformed, and in the past, when the collet chuck was clamped without a cutting bar attached, it was often irreversibly deformed and became unusable. Such troubles can be prevented by the above configuration.

Embodiment 2 The embodiment shown in FIGS. 3 and 4 similarly shows an example of application to a dental type air turbine handpiece, but the supply pipe line 41 of the pressure fluid 4 is connected to the inside of the handpiece body 10. The chuck portion is different from the above embodiment in that it is disposed in the above embodiment, and the chuck portion is substantially the same as in the above embodiment, so the same reference numerals will be given here, and a detailed explanation will be omitted, and the introduction section for the pressure fluid 4 will be described in detail. do.

A compressed air supply conduit 41 installed inside the handpiece body 10 reaches a threaded part 12 between the head part 1 and the cap 11, and a through hole 121 is provided in this threaded part 12 to supply the compressed air 4. This hole 121
It is introduced into the head section 1. A cylindrical air bypass collar 43 is fitted inside the cap 11.
A circumferential groove 431 is recessed in the collar 43 at a position corresponding to the through hole 121, and the circumferential groove 43
1, communication grooves 432..., 433 are formed on its circumferential body and back surface. An air supply hole 434 is opened at the center of the back of the collar 43, and the compressed air 4 from the supply pipe line 41 is passed through the through hole 121, the circumferential groove 431, the communication grooves 432..., 433... and the air supply hole 4.
34 into the collar 43. Color 4
A press plate 42 similar to the above is fitted in an airtight manner so as to be slidable back and forth, and is moved forward by the action of compressed air 4 introduced into the back surface of the press plate 42 to press the chuck means 2, thereby cutting. The grip on the bar 3 is released. Incidentally, reference numerals 122 and 122 in the figure are O-rings which are placed around the front and back of the threaded portion 12, and are designed to prevent the compressed air 4 from entering into the head portion 1. In the case of this embodiment, it is possible to provide the compressed air supply pipe 41 alone, but it can also be connected to the working medium pipe for dental treatment, for example, a pipe for chip air, etc. via an appropriate changeover switch (not shown). It is also possible to share them. In addition, in this embodiment, since the compressed air supply line 41 is installed inside the handpiece body 10, the operation may be hindered, unlike when the line is exposed on the outer periphery of the handpiece body. The advantage is that it never occurs.

FIG. 5 shows an overall view of a dental handpiece in which the same embodiment is adopted, and a touch switch 44 for turning on/off the introduction of compressed air is provided near the head portion 1 of the main body 10. If the touch switch 44 is provided in such a position, the operator can turn the switch 44 on and off with his or her index finger without changing the handpiece from the pen grip (the grip state during treatment) to turn the cutting bar 3. It can be exchanged.

Embodiment 3 FIG. 6 shows an example of an operational circuit diagram applied to the above embodiment. The solenoid valve 7 in the figure is a three-way valve installed in the middle of the piping from the compressor (not shown), and the foot switch 7
If you step on 1 to turn it ON, it will open to the air turbine side, and if you turn it OFF, it will open to the chuck operation side. A solenoid valve 45 for chuck operation is disposed in the middle of the chuck operation side piping, and opens after a time period set by a timer 72 has elapsed after the foot switch 71 is turned off. When the touch switch 44 is operated in this state, compressed air is introduced into the head 1 as described above, and the grip of the cutting bar 3 on the chuck means 2 is released, allowing it to be removed. According to such an operating circuit, even if the touch switch 44 is operated by mistake while the cutting bar 3 is rotating, the cutting bar 3 will not be released from the grip, which is safe, and is preferably adopted. Figure 7 shows this timing chart. During turbine operation (ON state), the chuck is closed (i.e., gripped state), and the chuck can be released after a predetermined period of time after the turbine is turned OFF. ing. In this case, chuck OPEN means that the solenoid valve 45 for chuck operation is opened, and therefore, the chuck will not be released unless the touch switch 44 is operated.

FIG. 8 shows a diagram of the pipe line configuration of the above embodiment. In the same figure, the three-way valve 7 is opened and closed by the operation signal of the foot switch, and when the foot switch is turned on, the air turbine side is opened, and compressed air is supplied to the air turbine supply pipe 50 through the pressure reducing valve 73, throttle valve 74, etc. is supplied. Meanwhile, turn off the foot switch
Then, the air turbine side of the three-way valve 7 is closed and the chuck side is opened. When the touch switch is turned on after the time set by the timer, the solenoid valve 45 for operating the chuck opens, and compressed air is supplied to the compressed supply pipe 41 for releasing the chuck.

FIG. 9 shows another embodiment of the pipe line configuration diagram, in which the solenoid valve 75 is a foot switch.
It is opened and closed by ON/OFF operation, and when the valve 75 is open, compressed air is supplied to the air turbine supply pipe 50 as described above. Also, the solenoid valve 45 for chuck operation opens and closes depending on whether the touch switch is turned on or off, but it remains closed while the valve 75 is open and during the timer setting time, and then when the touch switch is turned on, it opens and is used to release the chuck. Compressed air is supplied to the compressed air supply pipe line 41 . In addition, if the structure is such that the chuck is in a gripping state when air is being supplied and is released when the air supply is stopped, contrary to the above, when the valve 75 is open, It is also possible to maintain the valve 45 open and then close the valve 45 when the touch switch is turned on. Furthermore, it goes without saying that the pressure source in FIGS. 8 and 9 is not limited to compressed air.

In the above embodiment, the case where the chuck means 2 is gripped and released by sliding back and forth within the drive shaft 5 using the tapered surface is taken as an example, but the chuck means 2 is gripped and released by sliding back and forth within the drive shaft 5. Even when gripping and releasing the cutting bar by contracting and expanding the diameter as a coil spring expands and contracts, or gripping and releasing the cutting bar by elastically biasing and releasing the elastic force of a leaf spring placed around the cutting bar. If the pressure fluid 4 is introduced so that the chuck means 2 slides back and forth within the drive shaft 5 to act on either gripping or releasing, the same function as described above can be achieved. It is possible. In addition, in the embodiment, the grip on the cutting bar is released by introducing the pressure fluid, but the tapered surfaces of the tapered portion 211 and the drive shaft tapered portion 52 are made into a progressively closed shape in advance, so that the introduction of the pressure fluid is prevented. Therefore, it is also possible to have a configuration in which the cutting bar 3 is gripped and released at all times. Further, although the case where the drive shaft 5 is rotatably held by the bearings 6 has been shown, the case where the drive shaft 5 is held by an air bearing is not excluded. Furthermore,
In the illustrated example, a dental air turbine handpiece is taken as an example, but similar effects can be obtained if applied to a micromotor-driven or straight type handpiece, or even a rotary cutting tool for general work. It goes without saying that other modifications can be made without departing from the invention.

(Effects of the Invention) As described above, the chuck of the rotary cutting tool of the present invention grips and grips the chuck means of the cutting bar by the action of the pressure fluid introduced into the tip casing.
Since the bar is released, the cutting bar can be exchanged extremely easily by turning the bar on and off.Therefore, it can be replaced with a single touch without changing the grip or requiring strong operating force, which facilitates treatment work. It will be planned. In addition, there is no need for any tools for replacement as in the past, dramatically improving operability, and there is no need to worry about the cutting bar unexpectedly coming off during treatment as with the push-pull type, and a more secure gripping condition is ensured. It's safe. The present invention, which has many advantages as described above, is extremely useful.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the head portion of a dental handpiece to which the present invention is applied, Fig. 2 is an exploded perspective view of the chuck portion in the same embodiment, and Fig. 3 is a longitudinal sectional view of another embodiment. , FIG. 4 is an exploded perspective view of the pressure fluid introduction part in this embodiment, FIG. 5 is an overall view of the handpiece, FIG. 6 is an operation control circuit diagram, and FIG. 7 is a timing chart of the same. FIG. 8 is a diagram showing a conduit configuration adopted in the present invention, and FIG. 9 is a similar diagram of another embodiment. (Explanation of symbols), 1...Tip casing, 2...
. . . chuck means, 3 . . . cutting bar, 4 . . . pressure fluid.

Claims (1)

[Scope of Claims] 1. A chuck means provided within the cutting bar rotation drive shaft of the tip casing, which expands or contracts the inner diameter of the chuck by pressing the rear end in the axial direction of the cutting bar to release or grip the cutting bar. and,
A press plate is arranged behind the chuck means in the tip casing and moves in the axial direction of the cutting bar or presses the rear end of the deformable chuck means, and a pressurized fluid is provided in the tip casing to move or deform the press plate inside the tip casing. A chuck for a rotary cutting tool, characterized in that it consists of a means for supplying 2. The chuck for a rotary cutting tool according to claim 1, wherein the chuck means includes a collect chuck having a tapered portion, and the push plate presses the rear end of the collect chuck. 3. The chuck of a rotary cutting tool according to claim 1 or 2, characterized in that a switch for operating the introduction and stopping of pressure fluid into the tip casing is provided in the tool body near the tip casing. .