JP7717025B2 - File reciprocating motion generator - Google Patents

Description

This invention relates to a reciprocating motion generator that electrically generates a reciprocating motion to drive a file and cleanly treat decayed areas with the needle-shaped part of the file. Note that the term "file" as used in this invention includes a reamer for reaming and a file for filing, but this invention also includes similar treatment tools.

Dentists typically use handpieces called files when performing root canal treatments, such as scraping away the root wall of a patient's decayed tooth, removing pus-filled areas at the end of the root, or removing filling material left over from previous treatments, or removing nerves. As mentioned above, this includes reamers and files, with the name deriving from the words "reamer" (to widen) and "file" (to file). The handles of these tools are color-coded and marked with symbols or numbers depending on their purpose and size. A root canal locator is often used in conjunction with this type of root canal treatment.

The inventors disclosed the inventions in International Publication WO 2019/022255 and Japanese Patent Application Laid-Open No. 2019-150569 in order to provide dental tools that allow dentists to easily enlarge and clean root canals or extract nerves using files, thereby reducing fatigue and enabling them to maintain concentration. These tools achieved two major advances. First, by using a cam to drive the file back and forth by a motor or other device, the dentist no longer needs to forcefully advance the reamer to the apex of the root canal using only his or her fingers. Instead, the dentist simply needs to aim the needle tip of the file at the desired location in the root canal, reducing strain during the procedure and enabling them to maintain concentration. Second, the reciprocating motion generator is literally only made to move back and forth, and the file, i.e., the needle-shaped part of the file, is freely rotatable around its longitudinal axis. This means that the needle-shaped part does not encounter resistance in the rotational direction even with the complex shape of the root canal, and the needle-shaped part is significantly less likely to be twisted, making it difficult to move forward and backward within the root canal, or to be broken.

In developing this treatment tool, the inventors considered it convenient to be able to interchange commercially available files. They discovered that if the file were inserted from the rear and the needle-shaped portion projected from the front, the dentist would no longer need to look into the needle-shaped portion of the file to attach or detach the file's spindle from the front, reducing the sense of psychological resistance. However, to achieve this, both International Publication WO 2019/022255 and JP 2019-150569 could not provide a cam on the rear side of the file, as in Example 1. Instead, as in Examples 5 and 8, a pinhole was provided on the side of the vibrating tube housing the file, and a pin eccentrically attached to the tip of a rotating shaft connected to a drive source, such as a chair unit motor, was engaged with the pinhole to form a reciprocating motion generator.

While this improved the design for attaching and detaching the file, it created a new problem with the pin and pin hole when using the file for its intended purpose. The pin engages with a pin hole located eccentrically on the rotating shaft connected to the drive source, and the pin can only move a fixed distance from the start of rotation to the end of rotation. This is the same as with conventional contra-angles. Ideally, the rotation should start with a short movement, and then increase as the rotation speed increases. For example, when you press the foot switch on the chair unit, it should start with a short movement, gradually increasing in size. Starting with a small movement rather than a large movement from the beginning makes it easier to target the needle tip of the file to the desired location in the root canal, and it also reduces strain on the procedure, reduces fatigue, and allows for sustained concentration.

As a result of diligent research, the inventors have been able to provide the reciprocating motion generator for files disclosed in Japanese Patent Application Laid-Open No. 2021-137526. This device comprises a housing, a reciprocating motion generator housed within the housing, a vibrating cylinder attached to the reciprocating motion generator, and a file attachment/detachment unit attached to the vibrating cylinder, and is characterized in that the reciprocating motion generator is formed by a pin eccentrically attached to the tip of a rotating shaft connected to a motor, which engages with a pin hole on the side of the vibrating cylinder, and the pin is configured to be movable along an involute curve groove attached to the tip of the rotating shaft and to be always pulled to the center of the tip by a biasing means.

More specifically, an involute groove is provided at the tip of the rotating shaft, into which a pin is inserted. The pin moves along the involute groove, and a biasing means is provided between the center and the pin to always pull the pin toward the center. An involute curve is defined as a plane curve whose normal is always tangent to a fixed circle. Therefore, if a fixed circle is provided at the center of the tip of the rotating shaft, the pin moving along the involute groove is subjected to a force from the teeth, i.e., a force pushing in the axial direction of the file. However, the direction of this force must be nearly perpendicular to the involute curve at that position. In other words, the force pushing up from the file is received nearly perpendicularly by the wall of the involute groove, so the pin is supported by the wall of the groove and is not involuntarily returned toward the center. Therefore, the pin maintains its rotational diameter at this position.

Next, when the rotational motion of the rotating shaft is weakened, the centrifugal force acting on the pin weakens, causing the biasing means to pull the pin toward the center of the tip of the rotating shaft, causing the pin to return to its original position along the groove of the involute curve, as if rewinding a thread onto a spool, while the diameter of the rotational motion of the pin becomes smaller.

In this way, if the diameter of the pin's rotational motion is small, the distance of the reciprocating motion of the vibrating cylinder with the pin hole that this pin engages is small, and the larger the diameter of the pin's rotational motion, the greater the distance of the reciprocating motion of the vibrating cylinder.In other words, there was a big leap in the design where the position of the pin, which is installed eccentrically at the tip of the rotating shaft, changes from the center of rotation.

International Publication WO2019/022255 Patent Publication No. 2019-150569 Patent Publication No. 2021-137526

JP 2021-137526 was certainly an excellent invention. The force thrusting up from the file was received almost perpendicularly by the wall of the involute curve groove, so the pin was supported by the wall of the groove and was not inadvertently returned to the center, allowing the pin to maintain its rotational diameter at this position. However, sometimes, due to some kind of momentum, the pin would slip on the wall of the involute curve groove. This is thought to occur accidentally depending on the timing of the thrust from the file. If there are dentists who do not approve of this phenomenon, it is important to address it.

Therefore, the objective of this invention is to improve the invention of JP 2021-137526 A to minimize the problem of the pin slipping on the wall surface of the involute curve groove.

Therefore, this invention provides a reciprocating motion generator for a file, which comprises a housing, a reciprocating motion generating unit housed within the housing, a vibrating cylinder provided in the reciprocating motion generating unit, and a file attachment/detachment unit provided on the vibrating cylinder, wherein the reciprocating motion generating unit is constituted by a pin provided eccentrically at the tip of a rotating shaft connected to a motor that engages with a pin hole provided on the side of the vibrating cylinder, the pin is configured to be movable along an involute curve groove provided at the tip of the rotating shaft and is always pulled towards the center of the tip by a biasing means, and the outer edge of the involute curve groove has a curved groove into which the pin can fall.

A feature of this invention is that the outer edge of the involute curved groove has a curved groove into which the pin can fall. This allows the pin to fall into the nearest curved groove, preventing further slippage if it is supported by the wall of the outer edge of the groove due to the upward thrust from the file. This means that the pin can maintain its rotational diameter at this position, allowing the file to apply the force required for root canal treatment. Because the groove is curved, the centrifugal force acting on the pin increases or decreases, causing the pin to leave the curved groove and move along the involute curved groove.

In this way, the force thrust from the file is basically received almost perpendicularly by the wall of the involute curve groove, but at the moment the slip occurs, the curved groove effectively receives the slip of the pin, so the pin can maintain its rotational diameter at this position.

The detachable portion is configured so that the file is inserted from the rear side and the needle-shaped portion of the file protrudes from the front side, and a fixing means for securing the inserted file is provided at the rear of the detachable portion, and the pin hole may be provided around the entire circumference of the side portion of the vibrating cylinder so that the vibrating cylinder can passively rotate freely around the longitudinal axis of the file.

In this case, the pin holes are not located in one place on the side of the vibrating tube, but are located all around the side of the vibrating tube. With this configuration, even if the needle-shaped part of the file encounters resistance from the tooth in the direction of its rotation, it will rotate naturally and will not resist this resistance, which has the advantage that the file's forward and backward movement in the root canal is not heavy.

For attachment of a file or reamer, there is a configuration in which the front of the attachment/detachment part has an attachment opening for attaching the reamer shaft, which consists of the needle part of the reamer and the spindle, from the front, or a configuration in which the attachment/detachment part as described above has a file inserted from the rear and the needle part of the file protruding from the front. After the file is inserted, it is fixed with a fixing means so that it is firmly fixed to the electric reciprocating motion generator.

Although there is no problem with the former configuration, if there is a resistance to attaching or detaching the file shaft from the front with the needle-shaped part of the file facing the dentist, it is preferable to configure the file so that the entire shaft can be inserted or detached from the rear of the attachment/detachment section with the needle-shaped part facing away from the dentist. Also, this type of attachment/detachment method is relatively easy to use.

Alternatively, the detachable part can be configured so that the file is attached to its side. That is, a groove for receiving the file's shaft is provided on the side of the detachable part. This groove extends to the tip of the detachable part, so that the needle-shaped part of the file protrudes from the tip of the detachable part. Alternatively, a groove for receiving the file's shaft and needle-shaped part is provided on the side of the detachable part, and only the groove for the needle-shaped part is designed to extend to the tip of the detachable part.

Next, the detachable part is configured so that the file is inserted from the rear side and the needle part of the file comes out from the front side, and a fixing means for fixing the inserted file is provided at the rear of the detachable part, and the pin hole may be provided on the side part of the vibration cylinder over any angle less than 360 degrees so that the vibration cylinder can passively rotate freely around the longitudinal direction of the file as an axis.

The vibrating cylinder can freely rotate passively in either direction within this angle range. Therefore, even with this configuration, even if the needle-shaped part of the file encounters resistance from the tooth in the direction of its rotation, it will rotate naturally and will not resist, so there is an advantage that the movement of the file back and forth within the root canal does not become heavy.

Next, whether the pin holes are provided around the entire circumference of the side of the vibrating cylinder, or whether the pin holes are provided around any angle less than 360 degrees on the side of the vibrating cylinder, the reciprocating motion generating unit can be designed to be able to reciprocate the file any distance within a width of 0.4 mm to 2.0 mm.

As a result of the inventor's ongoing and intensive research, he has determined that in order to advance the needle-shaped portion of a file to the apex of a root canal during root canal treatment, it is preferable to design the file so that it can reciprocate any distance within a range of 0.4 mm to 2.0 mm. This range is similar to the distance range used when a hand file is held with the fingertips and manually moved up and down in small increments. Note that this range refers to the larger amplitude of the reciprocating motion of the pin inserted into the groove of the involute curve described above. Even if the larger amplitude of the involute curve is greater than this range, it may still be limited by the range within which the biasing means operates.

Next, whether the pin holes are provided around the entire circumference of the side surface of the vibrating cylinder, or whether the pin holes are provided around any angle less than 360 degrees on the side surface of the vibrating cylinder, the fixing means can be a push-in cap for the detachable portion.

There are various types of push-on caps, but one example is one in which a notch is provided on the inner circumference of the attachment/detachment part, and a ball that engages with this notch is biased in the protruding direction by a coil spring, and is provided on the push-on cap side. With a push-on cap, the cap can be attached to the vibration cylinder regardless of the rotation state of the vibration cylinder, as described below, and the operation can be done with a single push. Push-on caps as a fixing means will be described later.

Now, in the case where the pin hole is provided around the entire circumference of the side portion of the vibration cylinder, the fixing means may be a screw-type cap for the detachable portion, and a protrusion may be provided in the pin hole to obstruct the pin.

The pin holes are located around the entire side of the vibrating tube, allowing the vibrating tube to passively rotate around the longitudinal axis of the file. However, when inserting a file, even if you turn the screw cap to secure the file to the vibrating tube, the vibrating tube may rotate along with the screw cap, preventing the screw cap from tightening. Therefore, this problem can be avoided by providing a protrusion in the pin hole as an obstacle so that the pin can abut against this protrusion.

Next, in the case where the pin holes are provided around the entire circumference of the side portion of the vibrating cylinder, the fixing means may be a screw-type cap for the detachable portion, and the tip of the vibrating cylinder that moves back and forth may be arranged to always protrude from the housing so that it can be fixed by pressing a fingertip against this tip.

If the pin holes were provided around the entire side of the vibration cylinder, when you try to insert a file and turn the screw cap to secure it to the vibration cylinder, the vibration cylinder would rotate along with the screw cap, making it difficult to tighten the screw cap. However, if the tip of the vibration cylinder protrudes from the housing so that it can be touched with a finger, you can tighten the screw cap while placing your finger there to prevent it from rotating. This mechanism is also effective when applied to files with a rotation angle of less than 360 degrees, as described below.

That is, in the case where the pin holes are provided on the side surface of the vibration cylinder over any angle less than 360 degrees, the fixing means can be a screw-type cap for the detachable portion.

The screw cap is easy to use, and files can be replaced by simply attaching and detaching the screw cap. Because the vibration tube is able to rotate passively around the longitudinal axis of the file, there is no resistance when you first begin to tighten or loosen the screw cap. However, once the pin hits an obstacle, such as a wall in the circumferential direction of the pin groove, tightening or loosening actually becomes possible. This has the same effect as when a protrusion is provided as an obstacle in the pin hole, as described above.

The reciprocating motion generating device for the file described above may be a dental file that has a needle-shaped portion and a support shaft, and the needle-shaped portion is flexibly bendable. The reciprocating motion generating device described above is equipped with a file whose needle-shaped portion is flexibly bendable.

Furthermore, it would be convenient if commercially available hand files could be used as dental files for the present invention. Hand files are disposable, which is convenient from a hygienic standpoint.

The file reciprocation generator of this invention is characterized by the provision of a curved groove on the outer edge of the involute curved groove into which the pin can fall. Although the pin is supported by the wall of the outer edge of the groove due to the thrust from the file, if there is a moment when slippage occurs, the pin can fall into the nearest curved groove, preventing further slippage. The pin can then maintain its rotational diameter at this position.

Therefore, according to the present invention, it is possible to reduce the possibility of the pin slipping on the wall surface of the involute curve groove.

FIG. 2 is an explanatory diagram showing a part of the first embodiment in a cutaway view. FIG. 1 is an explanatory diagram of a first embodiment. FIG. 10 is an explanatory diagram of a pin insertion groove 23. 10 is an explanatory diagram of the operation state of the pin insertion groove 23 and the pin 28. FIG. FIG. 10 is an explanatory diagram showing a part of Example 2 in a cutaway view. 10A and 10B are explanatory diagrams illustrating the operating state of the vibration cylinder 43.

The following describes an embodiment of the present invention with reference to the drawings, but the present invention is not limited thereto. The file 3 in the following embodiment is composed of an insertion portion 30 (which also serves as a grip portion) and a needle-shaped portion 31, and the needle-shaped portion 31 is flexibly bendable. It is a file for filing based on the definition above, but it can also be designed to be used with a reamer for reaming or a similar cutting tool.

The reciprocating motion generator 1 of this embodiment will be described with reference to Figures 1 to 4. The reciprocating motion generator 1 comprises a handle-side housing 10 and a vibration-side housing 11 at its distal end. A vibration cylinder mounting port 12 is opened at the distal end of the vibration-side housing 11, and a vibration cylinder 13 is mounted therein. The vibration cylinder 13 is located inside the vibration-side housing 11 and is capable of vibrating in the front-to-back direction (the up-and-down direction in Figure 1). A file mounting port 16 is opened at the rear end of the vibration cylinder 13. When a file 3 is mounted through this port, its needle-shaped portion 31 slips out of the needle-through hole 15 of the vibration cylinder 13, and the distal end of the insertion portion 30 can be pushed into the needle-through hole 15 until it contacts the inside of the needle-through hole 15. A push-in cap 17 can be fitted into the file mounting port 16 to secure the file 3. Therefore, file 3 can be replaced by simply removing and attaching the push-in cap 17. Between the push-in cap 17 and the file attachment opening 16, a latch 18 is provided, which is made up of a notch on the file attachment opening 16 and a ball on the push-in cap 17 that fits into the notch and is biased by a coil spring, allowing the push-in cap 17 to be attached and detached. In this embodiment, a commercially available hand file can be used as the file 3.

The reciprocating motion generator 1 is connected to the rotary shaft of an electric motor of a chair unit (not shown) so as to be driven to rotate. A rotary shaft 20 is provided at the tip of a transmission shaft 2 connected to the rotary shaft of the electric motor, and the tip of this rotary shaft 20 is fixed to the back side of a disk 22 with a space 21 in its center.

3 and 4, the disk 22 is assumed to have a fixed circle at a position slightly outwardly away from the rotation axis of the transmission shaft 2, and an involute curve is assumed from this position extending from the outer periphery of the disk 22 to a position slightly inwardly, with the pin through-slot 23 engraved along this involute curve. Reference numeral 24 denotes the inner end of the pin through-slot 23, and reference numeral 25 denotes the outer end of the pin through-slot 23. The pin through-slot 23 is characterized in that its normal line is always tangent to the assumed fixed circle.

The pin groove 23 is provided so as to pass from the front side to the back side of the disk 22. As shown in Fig. 2, a pin 28 is fitted into this pin groove 23. A coil spring 200 is suspended between the portion of the pin 28 that protrudes toward the back side of the disk 22 and a latch 29 that protrudes near the rotation axis, so that the pin 28 is always biased toward the latch 29, i.e., toward the inner end 24, within the pin groove 23. Meanwhile, the portion of the pin 28 that protrudes toward the front side of the disk 22 engages with a pin hole 14 provided in the side portion of the vibration cylinder 13.

As shown in Figures 3 and 4, the pin passage groove 23 has a plurality of groove portions 27 provided at intervals on its outer edge portion 26, and is configured so that the pin 28 can move through the pin passage groove 23 by dropping into the groove portion 27 or coming out of the groove portion 27 and returning to within the involute curve when necessary.

When the electric motor of the chair unit is turned on, the disk 22 begins to rotate via the transmission shaft 2. As the disk 22 rotates, while the centrifugal force acting on the pin 28 is small, the pin 28 remains close to the inner end 24 of the pin groove 23, even against the force of the coil spring 200. However, as the centrifugal force acting on the pin 28 increases, the pin 28 moves in the pin groove 23 toward the outer end 25, resisting the force of the coil spring 200. This movement is directly reflected in the amplitude of the reciprocating motion of the vibrating cylinder 13.

The outer edge 26 of the involute curved pin groove 23 has a curved groove 27 into which the pin 28 can fall. The pin 28 is subjected to an upward force from the file 3, but the direction of this force is approximately perpendicular to the pin groove 23 at that position, as shown in FIG. 4 . However, if the pin 28 is supported by the wall of the outer edge 26 but slips at a moment, the pin 28 can fall into the nearest curved groove 27, preventing further slippage. In other words, the pin 28 can maintain its rotational diameter at this position, allowing the file 3 to apply the force required for root canal treatment at that time. Meanwhile, because the groove 27 is curved, the centrifugal force acting on the pin 28 increases or decreases, causing the pin 28 to leave the curved groove 27 and move along the involute curved pin groove 23.

In this way, the force thrust up from the file 3 is basically received almost perpendicularly by the wall surface of the outer edge 26 of the involute curved pin insertion groove 23, but at the moment the slip occurs, the pin 28 is effectively received by the curved groove portion 27. Therefore, the pin 28 can maintain the diameter of its rotational movement at this position.

When the electric motor of the chair unit is turned off, centrifugal force no longer acts on the pin 28, so the pin 28 is pulled by the coil spring 200 and moves toward the inner end 24 of the pin groove 23. This action is directly reflected in the amplitude of the reciprocating motion of the vibrating cylinder 13, as described above.

Through further research, the inventors have found that it is preferable to set the distance of reciprocation of the needle-shaped portion 31 within a range of 0.4 mm to 2.0 mm, which is the same distance as when a hand file is moved finely with the fingertips during treatment.

5 and 6 is similar in structure to the reciprocating motion generator 1 of the first embodiment, but the pin holes 44 provided in the vibrating cylinder 43 are characterized in that they are carved over 360 degrees around the outer periphery of the vibrating cylinder 43, unlike the pin holes 14 of the first embodiment which are carved only in one place on the side of the vibrating cylinder 13. Furthermore, the pins 53 of the disk 52 are engaged with the pin holes 44.

The reciprocating motion generator 4 comprises a handle-side housing 40 and a vibration-side housing 41 at its tip. A vibration cylinder mounting port 42 is opened at the tip of the vibration-side housing 41, and a vibration cylinder 43 is mounted here. A file mounting port 46 is opened at the rear end of the vibration cylinder 43. When a file 3 is mounted here, its needle-shaped portion 31 comes out of the needle-through hole 45 of the vibration cylinder 43, and it can be pushed in until the tip of the insertion portion 30 contacts the inside of the needle-through hole 45. The file mounting port 46 is configured so that the file 3 can be fixed in place by screwing a screw-type cap 47 into it. In this embodiment, a commercially available hand file can be used as the file 3, but a file specifically for the reciprocating motion generator 4 may also be prepared separately.

Although not shown, a fixed circle is assumed on the disk 52 at a position slightly outwardly away from the rotation axis 50 of the transmission shaft 5, and an involute curve is assumed from this position to a position slightly inwardly from the outer periphery of the disk 52, with the pin through grooves being engraved along this involute curve. The pin through groove is characterized in that its normal line always touches the assumed fixed circle.

The pin groove is provided so as to pass from the front side to the back side of the disk 52. A pin 53 is fitted into this pin groove. A coil spring is suspended inside the space 51 between the portion of the pin 53 protruding toward the back side of the disk 52 and a latch protruding from the rotation axis, so that the pin 53 is always biased toward the latch within the pin groove. Meanwhile, the portion of the pin 53 protruding toward the front side of the disk 52 is engaged with a pin hole 44 provided on the side surface of the vibrating cylinder 43. This configuration is similar to that of the reciprocating motion generator 1 in the first embodiment. As mentioned above, a feature of this embodiment is that the pin holes 44 are engraved 360 degrees around the outer periphery of the side surface of the vibrating cylinder 43.

The pin holes 44 are engraved 360 degrees around the outer periphery of the vibrating tube 43, allowing the vibrating tube 43 to rotate freely. This "free rotation" does not mean that the file 3 is forcibly rotated by a driving force, but rather that it is not fixed and can move freely in either direction without resisting external forces. This configuration prevents resistance to the reciprocating motion of the file 3 or the file 3 from digging into the root canal, making it less likely for the needle portion 31 to twist or bend, allowing the file 33 to continue reciprocating smoothly. Figure 6 is a schematic diagram showing the operating state.

The file attachment opening 46 is designed so that the file 3 can be secured by screwing in a screw cap 47, but if the pin holes 44 were engraved 360 degrees around the outer periphery of the vibrating cylinder 43, the vibrating cylinder 43 would rotate freely. Therefore, a protrusion 49 is provided in the cam groove 44 of the vibrating cylinder 43 as an obstacle, so that the pin 53 can abut against this protrusion 49. Alternatively, as shown by the chain line in Figure 6, the pin holes 400 may be provided in the cam groove 44 at an angle less than 360 degrees (120 degrees in this case) to the left and right.

The reciprocating motion generator 4 of this embodiment also includes a separate mechanism for preventing the free rotation of the vibrating cylinder 43. The exposed tip 48 of the vibrating cylinder 43 protrudes from the vibrating cylinder mounting port 42 so that it can always be touched with a finger. The exposed tip 48 of the vibrating cylinder 43, which reciprocates when inserting the file 3, always protrudes from the vibration-side housing 41 so that it can be fixed by pressing a finger against it. Pressing a finger against the exposed tip 48 prevents the vibrating cylinder 43 from rotating, and the screw cap 47 can be tightened. It is important to note during the design stage that the exposed tip 48 of the vibrating cylinder 43 must always protrude from the vibrating cylinder mounting port 42 so that it can be touched with a finger, regardless of the position of the pin 53.

This invention reduces the burden on dentists and improves treatment techniques, thereby contributing to the development of the industry. However, this invention is not limited to the above-mentioned embodiment. For example, the reciprocating motion generators 1 and 4 can be made independent of the chair unit and equipped with a power source such as an electric motor inside.

1: Reciprocating motion generating device 10: Handle side housing 11: Vibration side housing 12: Vibration cylinder mounting port 13: Vibration cylinder 14: Pin hole 15: Needle hole 16: File mounting port 17: Push-in cap 18: Hook 2: Transmission shaft 20: Rotating shaft 21: Space 22: Disk 23: Pin groove 24: Inner end 25: Outer end 26: Outer edge 27: Groove 28: Pin 29: Hook 200: Coil spring 3: File 30: Insertion portion 31: Needle-shaped portion 4: Reciprocating motion generating device 40: Handle side housing 41: Vibration side housing 42: Vibration cylinder mounting port 43: Vibration cylinder 44: Pin hole 45: Needle hole 46: File mounting port 47: Screw-type cap 48: Exposed tip portion 49: Convex portion 400: Pin hole end 5: Transmission shaft 50: Rotating shaft 51: Space 52: Disk 53: Pin

Claims (8)

A file reciprocating motion generator comprising a housing, a reciprocating motion generating unit housed within the housing, a vibrating cylinder provided in the reciprocating motion generating unit, and a file attachment/detachment unit provided on the vibrating cylinder, wherein the reciprocating motion generating unit is constituted by a pin provided eccentrically at the tip of a rotating shaft connected to a motor, which engages with a pin hole provided on the side of the vibrating cylinder, the pin being movable along an involute curve groove provided at the tip of the rotating shaft and being constantly pulled toward the center of the tip by a biasing means, and wherein the involute curve groove has a curved groove at the outer edge into which the pin can fall. 2. A file reciprocating motion generator as described in claim 1, wherein the detachable portion is configured so that the file is inserted from the rear side and the needle-shaped portion of the file protrudes from the front side, and a fixing means for fixing the inserted file is provided at the rear of the detachable portion, and the pin hole is provided around the entire circumference of the side portion of the vibration cylinder so that the vibration cylinder can passively rotate freely around the longitudinal direction of the file as an axis. The detachable portion is configured so that a file is inserted from the rear side and the needle-shaped portion of the file protrudes from the front side, and a fixing means for fixing the inserted file is provided at the rear of the detachable portion,
2. The file reciprocating motion generator according to claim 1, wherein the pin holes are provided on the side surface of the vibration cylinder over any angle less than 360 degrees so that the vibration cylinder can passively rotate freely around the longitudinal direction of the file as an axis. 4. A file reciprocation generator according to claim 2, wherein said reciprocation generator is designed to reciprocate the file over any distance within a range of 0.4 mm to 2.0 mm. 4. The reciprocating motion generating tool for a file according to claim 2 or 3, wherein said fixing means is a push-type cap for said detachable portion. 3. A reciprocating motion generating device for a file according to claim 2, wherein said fixing means is a screw-type cap for said detachable portion, and said pin hole is provided with a protrusion as an obstacle for said pin. The file reciprocating motion generator according to claim 2, wherein the fixing means is a screw-type cap for the detachable portion, and the tip of the vibrating cylinder that performs the reciprocating motion is arranged to always protrude from the housing so that it can be fixed by pressing a fingertip against this tip. 4. The reciprocating motion generating tool for a file according to claim 3, wherein said fixing means is a screw-type cap for said detachable portion.