JPS646820Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a cutting/polishing tool that cuts or polishes a workpiece or a polished object using a cutting/polishing blade fixed to the tip of a rotating shaft. It is related to.

(Conventional structure and its problems) Conventionally, cutting and polishing instruments, such as dental straight handpieces, have a rotating shaft rotatably installed in a cylindrical shank via a bearing, and a A collet-type chuck is installed at the tip so that it can move freely in the direction of the center line, a spring that biases this chuck toward the rear of the rotating shaft, and the inner end of the cam shaft that is rotatably inserted into the tube wall of the shank. It consists of a cam integrally formed with the camshaft and a lever fixed to the outer end of the camshaft.

In the conventional example configured in this way, the desired cutting tool is rotated by attaching the shank to the tip of the motor, connecting the rotating shaft to the drive shaft of the electric motor, and rotating the lever to open and close the chuck. Fix it to the shaft. Next, when the electric motor is driven to rotate the rotating shaft, the cutting tool rotates and the object to be cut or polished can be cut or polished. By the way, the tip of the shank is open to the extent that the tip of the rotating shaft and the tip of the chuck can be seen through, so during cutting or polishing, dust from the object to be cut or polished can escape from between the shank and the rotating shaft. When the cutting tool is inserted, the dust adhering to the tip of the rotating shaft and the tip of the chuck is pushed into the chuck along with the cutting tool, and also adheres to the bearing, causing abnormal wear on the bearing. This phenomenon was particularly noticeable when dust from gypsum, which is often used in dentistry, adhered to the bearing.

(Purpose of the invention) The purpose of the invention is to prevent dust from entering the shank during cutting or polishing.

(Structure of the invention) The present invention covers the tip opening of the shank with a ring-shaped cover that rotates together with the cutting tool.

(Description of an embodiment) The figure shows the configuration of an embodiment of the present invention.
1 is a substantially cylindrical shank connected to the tip of a motor (not shown) having a built-in electric motor, 2 is a conical portion 3 that widens toward the end, and is formed on the inner peripheral wall surface of the tip opening;
A guide hole 4 is drilled in the center line direction in the pipe wall at the intermediate portion, and an engagement groove 5 is provided at the rear end to engage with a protrusion (not shown) protruding from the outer peripheral wall surface of the tip of the drive shaft of the electric motor. A rotary shaft bored in the pipe wall, 6 a dust stopper fitted inside the middle part of the rotary shaft 2, 7 a bearing for rotatably holding the rotary shaft 2 in the shank 1, 8 a
This chuck (hereinafter referred to as chuck) has a conical portion 9 that widens toward the end formed on the outer circumferential wall surface of the distal opening, and a slot 10 is bored in the tube wall at the distal end in the direction of the center line. It is attached to the inside of the front part so that it can be slid freely in the direction of the center line.
11 is a cutter stopper screwed onto the rear end of the chuck 8; 12 is a ring-shaped push fitting slidably attached to the outside of the rotating shaft 2; and 13 is a cutter stopper 11 that is inserted into the guide hole 4. and push metal fittings 12
14 is a collar fixed to the outer peripheral wall surface; 15 is a spring interposed between the pusher 12 and the collar 14; the tension of the spring 15 causes the pusher 12, pin 13 and Cutting tool stopper 1
The chuck 8 is biased toward the rear of the rotating shaft 2 through the chuck 1, and the mouth of the chuck 8 where the conical portion 9 slides into contact with the conical portion 3 of the rotating shaft 2 is closed. Reference numeral 16 indicates a lever bearing fitting screwed onto the intermediate tube wall of the shank 1, and 17 indicates a camshaft with a cam 18 integrally formed at one end. It is rotatably supported by a lever bearing fitting 16 at a position where it comes into contact with the push fitting 12 urged by the lever bearing fitting 16. 19 is the lever bearing fitting 16
Insert the washer 20 between the shank 1 and the lever 19 fixed to the other end of the camshaft 17 protruding from the outer peripheral wall of the shank 1, and rotate the lever 19 from the position shown in the figure to push the cam 18 onto the pusher fitting 12. When the lever 19 is rotated against the tension of the spring 15 after making contact, the chuck 8 is moved forward of the rotation shaft 2 together with the pusher 12 which is pressed forward by the cam 18. Moving, the mouth of chuck 8 opens,
Also, return the lever 19 to the position shown and release the cam 18.
When the chuck 8 is released from the pusher 12, the tension of the spring 15 moves the chuck 8 together with the pusher 12 to the rear of the rotating shaft 2, and the mouth of the chuck 8 is closed. 21
1 is a lever fixing member installed in the lever 19 in a state where it is urged downward in the figure by a spring (not shown), and this lever fixing member 21 is attached to the shank 1.
When the lever 19 is fitted into the hole 22 formed in the outer circumferential wall of the lever 19, the lever 19 is prevented from moving freely. Reference numeral 23 denotes two ring-shaped seal plates protruding from the inner circumferential wall surface of the tip end of the shank 1, and the inner end of the seal plate 23 is connected to the rotating shaft 2.
It is close to the outer peripheral wall of. 24 are two ring-shaped seal plates protruding from the outer circumferential wall surface of the tip end of the rotating shaft 2 so as to be alternately positioned with the seal plates 23;
The outer end of this seal plate 24 is close to the inner circumferential wall surface of the shank 1. Reference numeral 25 includes a front wall portion 27 having a through hole 26 in the center thereof, an outer wall portion 28 annularly protruding rearward from the outer peripheral edge of the front wall portion 27, and an inner peripheral edge of the front wall portion 27. This cover consists of an inner wall part 29 that protrudes rearward in an annular shape from the inner wall part 29, and a ring groove 30 is formed in the inner circumferential wall surface of the inner wall part 29 of this cover 25 in the circumferential direction.
is recessed. Reference numeral 31 denotes a closing ring made of an elastic member, and this closing ring 31 is fitted into the ring groove 30. Reference numeral 32 denotes a bearing interposed between the inner circumferential wall surface of the distal end of the shank 1 and the inner circumferential wall surface of the inner wall section 29. With this bearing 32, the front wall section 27 covers the distal end opening surface of the shank 1, and the outer wall section 28 cover the outer periphery of the tip of shank 1, and then cover 2.
5 is rotatably attached to the tip of the shank 1.

In this embodiment configured in this way, first, the shank 1 is connected to the tip of the motor, the rotating shaft 2 is connected to the drive shaft (not shown) of the electric motor, and the lever 19 is rotated to start the chuck. By opening and closing 8, a desired cutting tool 33 is fixed to the rotating shaft 2. Next, when the electric motor is driven to rotate the rotating shaft 2, the cutting tool 33 rotates, and the object to be cut or polished can be cut or polished.

By the way, the opening surface and the outer peripheral edge of the tip of the shank 1 are covered with a cover 25, and
A closing ring 31 is fitted in the inner peripheral wall surface of the inner wall portion 29 of the cover 25 in the circumferential direction, and a closing ring 31 is fitted in the inner peripheral wall surface of the inner peripheral wall portion 29 of the cover 25 to provide a space between the inner peripheral wall surface of the inner peripheral wall portion 29 of the cover 25 and the outer peripheral wall surface of the cutting tool 33 fixed on the chuck 8. is sealed, so
Even if dust from the object to be cut or polished attempts to enter from the tip of the shank 1 during cutting or polishing, the cover 25 and the closing ring 31 prevent this intrusion. By the way, cover 25
is rotatably attached to the tip of the shank 1 by a bearing 32, and the closing ring 31 and the cutting tool 3
3 are in sliding contact, so when the cutter 33 rotates, the cover 25 rotates with the cutter 33 due to the friction generated between the closing ring 31 and the cutter 33. Therefore, during cutting or polishing, dust that hits the cover 25 or the closing ring 31 is blown away by the rotational force, or
The centrifugal force generated by the dust attached to the cover 2
5, no dust remains on the cover 25 or the closure ring 31.

Furthermore, even if dust adheres to the cutting tool 33 attached to the rotating shaft 2, the dust is wiped off by the closing ring 31 that slides on the cutting tool 33 when the cutting tool penetrates, and the dust is removed when the rotating shaft 2 rotates. The cover 25 or the closing ring 3 is removed by the centrifugal force acting on the dust.
1, no dust remains on the cover 25 or the closure ring 31.

Therefore, the cover 25 or the closing ring 31 prevents dust from entering the shank when the cutting tool 33 is inserted into and removed from the shank 1, or during cutting or polishing.

(Effects of the invention) As explained above, according to the invention, the dust attached to the cutter etc. is wiped away by the closing ring when the cutter etc. penetrates, and the gap between the cutter etc. and the cover is wiped away by the closing ring. The cover and the closure ring are thus sealed, and dust adhering to the cover or closure ring is discharged by the cover and closure ring that rotate with the cutting tool, so that no dust remains on the cover and the closure ring. As a result, there is an advantage that dust is prevented from entering the shank, and abnormal wear of the bearing can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view of the tip of an embodiment of the present invention. 1...Shank, 2...Rotating shaft, 8...Chuck, 26...Through hole, 29...Inner wall portion, 31...
Occlusion ring, 33...cutting tool.

Claims (1)

[Scope of Claim for Utility Model Registration] A cutting/polishing tool that cuts or polishes a workpiece by fixing a cutting tool, etc. to the tip of a rotary shaft rotatably mounted in a shank, which penetrates the cutting tool, etc. a cover provided with a through hole in the center for the opening of the shank; a bearing rotatably attached to the tip of the shank, the cover covering from the opening surface of the tip of the shank to the outer peripheral edge of the tip of the shank; and a closure ring made of an elastic member attached to the inner wall of the block, and when the cutter etc. is penetrated while slidingly contacting the closure ring, dust adhering to the cutter etc. is removed from the closure ring when the cutter etc. penetrates. In addition to being wiped by the ring, the space between the cutter etc. and the cover is sealed by the closing ring, and when the cutter etc. rotates, the cover rotates with the cutter etc. . A cutting/polishing instrument, characterized in that the dust is prevented from adhering to the cover and the closure ring.