JP3772158B2 - Medical handpiece - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a medical handpiece that cuts bones or teeth with a cutting tool that is driven to rotate by transmitting power from a driving source.
[0002]
[Prior art]
Medical handpieces for cutting bones or teeth have been used in the past. In general, a medical handpiece is configured such that a cutting tool is detachably attached to a main shaft, and the main shaft is rotationally driven by power from a driving source such as a motor, and thereby the bone or teeth are cut with the cutting tool driven to rotate. To do.
[0003]
In the medical handpiece as described above, while the cutting tool is driven to rotate at a relatively high speed, the torque acting on the cutting tool at the time of cutting is relatively small. Therefore, the cutting tool detachably attached to the spindle is The state of being securely held even during rotation driving is maintained, and no problem such as idling occurs. However, in the future, the range of use of medical handpieces will expand, and there is a possibility that a relatively large torque will act on the cutting tool when used in various procedures.
[0004]
[Problems to be solved by the invention]
Therefore, in order to deal with the above-described possibility, the problem of the present invention is that the cutting tool can be securely gripped even during rotational driving, and the cutting tool can be reliably prevented from idling. It is to provide a handpiece.
[0005]
[Means for Solving the Problems]
In the present invention, a cutting tool such as a blade for cutting bones or teeth is provided at the tip of the shank, and the shank of the cutting tool is detachably held and is transmitted by power transmitted from a driving source. A main shaft that is driven to rotate; a bearing member that rotatably supports the main shaft ; and a casing that houses the cutting tool, the main shaft, and the bearing member therein, and the main shaft includes a shank of the cutting tool. A hole for inserting the collet is formed in the axial direction, and a collet in which a slit is formed and a collet pressing member that presses the collet to reduce the diameter are inserted into the hole. A hole for inserting the rear end of the shank is formed in the member in the axial direction, and a receiving portion that engages with each other is engaged at a position opposite to the hole of the collet pressing member and the rear end of the shank. parts and each Medical handpiece, characterized in that eclipse has are provided.
In the medical handpiece described above, the shank engaging portion of the cutting tool and the receiving portion of the main shaft are engaged with each other, so that even if a relatively large torque acts on the cutting tool, the shank and the main shaft are relatively Can be prevented from occurring.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
As shown in FIGS. 1 to 3, the medical handpiece 10 detachably holds a cutting tool 28 having a cutting work portion such as a blade provided at the tip of the shank 28 a and the shank 28 a of the cutting tool 28. The main shaft 20 that is rotationally driven by the power transmitted from the drive source, bearing members 15a and 15b that rotatably support the main shaft 20, and the cutting tool 28, the main shaft 20, and the bearing members 15a and 15b are accommodated therein. The shank 28a of the cutting tool 28 and the main shaft 20 are provided with engaging portions 28b and 24b that are engaged with each other.
[0007]
Here, in the cutting tool 28 shown in FIG. 3, a cutting work portion (not shown) such as a blade for cutting bone or teeth is provided at the front end of the shank 28a, and an engaging portion 28b is formed at the rear end. Has been. The engagement portion 28b in FIG. 3 is formed by scraping the rear end peripheral surface of the shank 28a into an octagon, but the engagement portion at the shank rear end is not limited to this shape, for example, Further, it can be formed in a polygonal shape such as a triangle or a square, and it can also be formed in a half-moon notch like the engaging portion 38b in FIG.
[0008]
As shown in FIG. 2, the main shaft 20 is formed with a hole 21b extending in the axial direction from the front end to the rear, and a first shaft provided with a connecting portion 21c for connecting a motor unit or the like at the rear end. 21, a collet 23 inserted in the hole 21 b, a collet pressing member 24, a spring 19, and a second shaft 22 screwed into the tip of the first shaft 21.
The collet 23 has a through hole 23e through which the shank 28a of the cutting tool 28 is inserted, tapers 23b and 23c are formed at the front and rear ends, and the slits 23a and 23d are respectively extended from the front end and the rear end to the middle. ing. The collet pressing member 24 is a tubular member having a through hole 24e for inserting the rear end of the shank of the cutting tool 28, and an inner periphery of the front end for reducing the diameter by pressing the collet 23 from the rear. Are provided with a taper 24a, a complementary receiving portion 24b is formed on the inner periphery so as to engage with the engaging portion 28b of the cutting tool 28, and a pin hole 24c for inserting the pin 26 is formed. Yes. Both ends of the pin 26 protrude outward from a long hole 21 a formed in the first shaft 21 and engage with the inner peripheral groove 17 a of the slide ring 17. Further, a taper 22 a is formed on the inner periphery of the rear end of the second shaft 22, and this taper 22 a is opposite to the front end taper 23 b of the collet 23.
In the main shaft 20, the collet pressing member 24 and the collet 23 are slidable inside the hole 21 b of the first shaft 21, and the collet pressing member 24 is always urged in the direction of arrow B by the spring 19. Therefore, the taper 24a of the collet pressing member 24 contacts the rear end taper 23c of the collet 23 and pushes the collet 23 forward, while the front end taper 23b of the collet 23 has a taper 22a of the second shaft 22. A contact force is applied to the collet 23, and the collet 23 is elastically deformed to be reduced in diameter by being pressed from the front and back in this way.
[0009]
A slide ring 17 is slidably mounted on the outer periphery of the main shaft 20, a tubular body 16 is mounted on the outer periphery of the slide ring 17, and a chuck opening / closing ring 12 is mounted on the outer periphery of the tubular body 16. Has been. A longitudinal groove is formed in the inner periphery of the chuck opening / closing ring 12, a connecting screw 18 protruding from the inner periphery is fitted in the longitudinal groove, and a guide groove 16a through which the connecting screw 18 is inserted is a tubular body. The slide ring 17 is provided with a hole 17b that is drilled in 16 and into which the tip of the connecting screw 18 fits. A spring 20 is provided in front of the slide ring 17, and the slide ring 17 is always urged in the direction of arrow A in FIG.
Since the guide groove 16a is formed slightly obliquely as shown by a one-dot chain line in FIG. 1, when the chuck opening / closing ring 12 is rotated clockwise when the front of the medical handpiece 10 is viewed from the rear, the guide groove 16a is connected. The screw 18 is guided to the guide groove 16a, and the slide ring 17 moves slightly rearward. As a result, the inner circumferential groove 17a of the slide ring 17 pushes the pin 26 rearward and the collet pressing member 24 also moves rearward, so that the reduced diameter state of the collet 23 is loosened and the cutting tool 28 gripped by the collet 23 is obtained. This shank 28a can be removed.
[0010]
The engaging part between the shank of the cutting tool and the main shaft will be described with reference to FIGS. 3, in the shank 28a of the cutting tool 28, the rear end peripheral surface is scraped off into an octagonal shape to form an engaging portion 28b, and the engaging portion 24b on the main shaft side is inside the through hole 24 of the collet pressing member 24. The peripheral surface is formed in an octagon shape so that the engaging portion 28b of the shank 28a can be fitted. FIG. 4 shows an engaging portion having a shape different from that in FIG. 3. The shank 38a of the cutting tool 38 forms the engaging portion 38b by scraping the peripheral surface of the rear end into a half-moon shape. The engagement portion 24b is formed by making the inner peripheral surface of the through hole 24 of the collet pressing member 24 into a hole into which the half-moon-like engagement portion 38b of the shank 38a fits.
[0011]
【The invention's effect】
In the medical handpiece of the present invention, since the engaging portions that engage with each other are provided at opposite positions of the shank of the cutting tool and the main shaft, these engaging portions are engaged with each other, and compared when rotating. Even if an excessively large torque acts on the cutting tool, the cutting tool can be reliably gripped, and the idling of the cutting tool can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a medical handpiece of the present invention.
2 is a cross-sectional view showing a main shaft and other configurations of the medical handpiece of FIG. 1; FIG.
3 is a perspective view showing an engaging portion provided on a shank and a main shaft of a cutting tool in the medical handpiece of FIG. 1. FIG.
4 is a perspective view showing an engaging portion having a shape different from that of FIG. 3; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Medical handpiece 11, 13 Casing 15a, 15b Bearing member 20 Main shaft 24b Engagement part 28 Cutting tool 28a Shank 28b Engagement part

Claims (1)

A cutting tool such as a blade for cutting bone or teeth is provided at the tip of the shank, and the shank of the cutting tool is detachably held and is rotationally driven by the power transmitted from the drive source. A main shaft, a bearing member that rotatably supports the main shaft, and a casing that accommodates the cutting tool, the main shaft, and the bearing member therein,
A hole for inserting the shank of the cutting tool is formed in the main shaft in the axial direction, a collet formed with a slit in the hole, and a collet press for pressing the collet to reduce the diameter. And a hole for inserting the rear end of the shank is formed in the axial direction in the collet pressing member, and the hole between the collet pressing member and the rear end of the shank is located at the opposite position. A medical handpiece characterized in that a receiving part and an engaging part are provided to engage each other.

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