JP5793838B2 - Shaft cylinder - Google Patents

Description

  The present invention relates to a shaft tube such as a shaft tube of a writing instrument or a cosmetic container, which is connected by screwing and fixed so as to be unscrewable after the connection.

  2. Description of the Related Art Conventionally, shaft cylinders that connect two components such as a front shaft and a rear shaft are known to be connected by screwing or connected by engagement of an uneven portion. The shaft cylinder connected by screwing is less susceptible to variations due to molding errors of parts during manufacturing, compared to the shaft cylinder connected by engagement of the concave and convex portions. Even if there is some variation, the surface portions of the male screw portion and the female screw portion are brought into contact with each other by being screwed together, and further, by tightening when the screwing is completed, the gap for the variation is eliminated. It is because it can suppress by the strong frictional force by the contact of the said surface parts. That is, when two parts are connected by screwing, the shaft tube can be connected without tightness and play. For this reason, the means by screwing is suitable not only for connecting two parts but also for fixing them.

  Here, Japanese Utility Model Publication No. 5-39985 discloses a related art relating to a shaft cylinder in which two parts are connected by screwing and the screwing is completed after screwing is completed. The first and second engagement protrusions are provided on the mutually opposing surfaces of the shaft cylinder and the front cylinder that are connected by screwing, and the first and second engagement protrusions are engaged when the screwing is completed. That's it. When the shaft cylinder is rotated in the side surface of the first and second engaging protrusions on the inner side in the screwing rotation direction, that is, in the direction in which the screwing is released (hereinafter referred to as the screwing release rotation direction). The side surface with which the engagement protrusion comes into contact is formed in a standing position, and the second engagement protrusion cannot get over the first engagement protrusion. For this reason, after completion of screwing, the release becomes impossible and screwing does not loosen. As a result, the shaft tube and the tip shaft are fixed.

Japanese Utility Model Publication No. 5-39985

However, in general, in the connection of parts by screwing, it is considered that the number of threads (threads) that the screw bites is insufficient when the tip tube is a small part. Further, when the screw is formed by forcibly removing it, it is conceivable that the height of the screw thread is reduced and the contact force between the male screw portion and the female screw portion cannot be sufficiently obtained.
Here, in the above-described prior art, the loosening prevention, that is, the fixing between the shaft tube and the tip tube is performed in the screwing release rotation direction (the circumferential direction of the shaft tube). For this reason, when the direction in which the front tube is inserted into the shaft tube is taken as the connecting direction, if the shaft tube and the front tube are pulled away in the direction opposite to the connecting direction, the connecting direction is opposite. In this direction, there is only a restriction by a screw thread, so that one screw thread could get over the other screw thread and the shaft tube and the tip tube could easily be detached.

The present invention has been made in view of the above problems, and is a shaft cylinder formed by connecting a first shaft cylinder and a second shaft cylinder by screwing, and when the screwing is completed, a convex portion and a concave portion are formed. It is provided on the barrel of each of the engaging portion engaged by, the recess and window hole, also on the side of engagement of the engaging portion, thereby forming a vertical surface with respect to the connecting direction The first gist is that the engaging portion abuts also in the circumferential direction of the shaft tube .
Each shaft cylinder is provided with an engaging portion that is engaged with the convex portion and the concave portion when the screwing is completed. In addition, the concave portion is a window hole portion, and the vertical cross-sectional shape of the engagement surface of the convex portion with the concave portion is a shape having a concave portion with respect to the coupling direction, and the convex portion in the concave portion The vertical cross-sectional shape of the engaging surface is a shape having a convex portion that engages with the concave portion, and the second gist is that the engaging portion also contacts in the circumferential direction of the shaft tube .

The first aspect of the present invention is a shaft cylinder formed by connecting a first shaft cylinder and a second shaft cylinder by screwing, and is engaged by a convex part and a concave part when screwing is completed. A joint portion is provided in each shaft tube, the concave portion is used as a window hole portion, a surface portion perpendicular to the coupling direction is formed on the engaging side of the engaging portion, and the engaging portion However, even in the circumferential direction of the shaft cylinder, even if the number of screw threads or the height thereof is insufficient, the first shaft cylinder and the second shaft cylinder are separated from each other, That is, when the first shaft cylinder and the second shaft cylinder are pulled in the direction opposite to the connecting direction, the first shaft cylinder and the second shaft cylinder do not come out, and the first shaft The cylinder and the second shaft cylinder can be securely fixed.
Each shaft cylinder is provided with an engaging portion that is engaged with the convex portion and the concave portion when the screwing is completed. In addition, the concave portion is a window hole portion, and the vertical cross-sectional shape of the engagement surface of the convex portion with the concave portion is a shape having a concave portion with respect to the coupling direction, and the convex portion in the concave portion The vertical cross-sectional shape of the engaging surface is a shape having a convex portion that engages with the concave portion, and the engaging portion abuts also in the circumferential direction of the shaft cylinder. Since the portion engages so as to cover the convex portion of the other engaging portion, even if the first shaft tube and the second shaft tube are pulled in the direction opposite to the connecting direction, the first shaft tube can be more reliably secured. One shaft cylinder and the second shaft cylinder can be fixed.

It is an external view of the whole product of the first example. It is a longitudinal cross-sectional view of FIG. It is the longitudinal cross-sectional view which expanded the back of the front shaft of the 1st example. It is an external view of the rear axis of the first example. It is a longitudinal cross-sectional view showing the screwing completion state of the front shaft and the rear shaft of the first example. It is a longitudinal cross-sectional view of the entire product of the second example. It is a longitudinal cross-sectional view of the front shaft of the second example. It is an external view of the rear axis of the second example. It is a longitudinal cross-sectional view showing the screwing completion state of the front shaft and the rear shaft of the second example. FIG. 10 is a longitudinal sectional view as seen from a direction rotated 90 degrees in the state of FIG. 9. FIG. 10 is an AA cross-sectional view (transverse cross-sectional view) in the state of FIG. 9. It is a longitudinal cross-sectional view of the front shaft of the third example. It is an external view of the rear axis of the third example. It is the longitudinal cross-sectional view seen from the direction rotated 90 degree | times in the state of FIG. It is a longitudinal cross-sectional view showing the screwing completion state of the front shaft and the rear shaft of the third example. It is the longitudinal cross-sectional view seen from the direction rotated 90 degree | times in the state of FIG. It is the elements on larger scale near the engaging part in FIG. FIG. 16 is a BB sectional view (transverse sectional view) in the state of FIG. 15. It is a longitudinal cross-sectional view of the front shaft of the fourth example. It is a longitudinal cross-sectional view showing the screwing completion state of the front shaft and the rear shaft of the fourth example. In the state of FIG. 20, it is the longitudinal cross-sectional view seen from the direction rotated 90 degree | times. It is CC sectional drawing (transverse sectional view) in the state of FIG. It is a longitudinal cross-sectional view of the front shaft of the fifth example. It is a longitudinal cross-sectional view showing the screwing completion state of the front shaft and the rear shaft of the fifth example. It is the longitudinal cross-sectional view seen from the direction rotated 90 degree | times in the state of FIG. It is DD sectional drawing (transverse sectional view) in the state of FIG.

  A first example will be described with reference to FIGS. In this example, the present invention is developed on a mechanical pencil as a writing instrument. The present invention can be used for writing instruments such as ballpoint pens and applicators, cosmetic containers, and the like in addition to mechanical pencils.

The shaft tube 1 includes a tip member 3 in which a core holding member 2 is press-fitted and fixed, a front shaft (first shaft tube) 4 detachably screwed to a rear end of the tip member 3, and a front thereof. A rear shaft (second shaft cylinder) 5 is screwed to the rear end of the shaft 4 so as not to be detachable. A core feeding means 6 is disposed inside the shaft cylinder 1.
The front shaft 4 has a reduced diameter portion 7 formed in the front, and a grip 8 made of a thermoplastic elastomer or silicone is disposed on the outer periphery of the reduced diameter portion 7. In this example, the grip 8 is inserted into the front shaft 4. On the other hand, the rear shaft 5 is integrally provided with a clip 9 on the rear outer peripheral surface thereof. The clip 9 has a curved shape as a whole, and a ball portion 10 is formed on the front shaft cylinder 1 side.

  Next, the lead feeding means 6 will be described in detail. In the lead feeding means 6 of this example, a chuck body 11 for gripping and releasing the lead L is disposed in front of the shaft cylinder 1, and a chuck ring 12 for opening and closing the chuck body 11 is provided in the chuck body 11. Is inserted in a state of Go. A lead tank 13 that houses the lead L is press-fitted and fixed behind the chuck body 11. A press-fit fixing portion of the lead tank 13, that is, a front portion of the lead tank 13 is a reduced diameter portion 14, and a step portion 15 is formed on the outer peripheral surface of the lead tank 13 by the reduced diameter portion 14. . On the other hand, a step 16 is also formed on the front inner peripheral surface of the front shaft 4. Between the step portion 15 of the lead tank 13 and the step portion 16 of the front shaft 4, an elastic member (coil spring) 17 that urges the lead feeding means 6 toward the rear of the shaft cylinder 1 is mounted.

Next, the rear part of the mechanical pencil will be described in detail. A step portion 18 is formed on the rear inner peripheral surface of the core tank 13. An eraser 19 is inserted behind the lead tank 13, and the eraser 19 is positioned by a step portion 18 of the lead tank 13.
A flange 20 and a recess 22 are formed on the rear outer peripheral surface of the core tank 13. The concave portion 22 is located behind the collar portion 20. A pressing member 21 is fitted behind the lead tank 13 so as to cover the eraser 18. On the inner peripheral surface of the pressing member 21, a convex portion 23 that engages with the concave portion 22 of the core tank 13 is formed, so that the core tank 13 and the pressing member 21 can be fitted. . Further, a pressing member cover 24 made of a thermoplastic elastomer or silicone is disposed behind the pressing member 21, and a through hole 25 is formed on the top surface of the pressing member 21.

  When using a mechanical pencil, the pressing member 21 is pressed toward the front of the shaft tube 1. As a result, the lead tank 13 and the chuck body 11 press-fitted and fixed to the lead tank 13 are pressed forward to move forward. At this time, the lead L is also moved forward, the chuck ring 12 comes into contact with the step portion 26 provided on the inner peripheral surface of the tip member 3, and the chuck body 11 is expanded. And even after the chuck body 11 is expanded, the forward movement of the chuck body 11 is performed. When the pressing operation of the pressing member 21 is released here, the lead tank 13 and the chuck body 11 are retracted, the chuck body 11 is closed by the chuck ring 12, and the lead L is gripped again. This completes the lead L feeding operation.

The configuration of the front shaft 4 and the rear shaft 5 and the connection thereof will be described in detail.
FIG. 3 is an enlarged longitudinal sectional view of the rear side of the front shaft 4. A female screw portion 27 is formed on the rear inner peripheral surface of the front shaft 4. In front of the female screw portion 27, an enlarged diameter portion 28 having an enlarged inner diameter is provided, and a step portion (engagement portion) 29 is formed by the enlarged diameter portion 28. The step portion 29 is formed perpendicular to the inner peripheral surface of the front shaft 4, that is, perpendicular to the connecting direction of the front shaft 4 and the rear shaft 5. In the following, the connecting direction between the front shaft 4 and the rear shaft 5, that is, the direction when the rear shaft 5 is inserted into the front shaft 4, is referred to as "connecting direction" or "shaft tube connecting direction". It describes.
On the other hand, FIG. 4 is an enlarged external view of the rear shaft 5. A male screw portion 30 is formed on the outer peripheral surface of the central portion of the rear shaft 5, and the rear shaft 5 can be screwed to the front shaft 4. A convex portion (engagement portion) 31 that can be engaged with the step portion 29 of the front shaft 4 is formed on substantially the entire circumference on the outer peripheral surface of the rear shaft 5 in front of the male screw portion 30. The convex portion 31 has an arrow shape as a whole, and is positioned in front of the surface portion 32 perpendicular to the outer peripheral surface of the rear shaft 5 and the vertical surface portion 32, and is in the axial direction, that is, the radial center of the rear shaft 5. And an inclined surface portion 33 inclined toward the direction. The surface portion 32 is formed perpendicular to the connecting direction of the shaft tube and engages with the step portion 29 of the front shaft 4. Further, two slits 34 are formed on the front outer peripheral surface of the rear shaft 5 at opposing positions, and the front end thereof is open.

Next, the operation will be described. When the rear shaft 5 is screwed to the front shaft 4, the rear shaft 5 is formed with a slit 34, so that the portion where the convex portion 31 is formed is inwardly bent while being bent inward. Go forward. The slit 34 allows the front portion of the rear shaft 5 to be elastically deformed. When the front shaft 4 and the rear shaft 5 are screwed together, the slit 34 is expanded, and the step portion 29 of the front shaft 4 and the convex portion 31 of the rear shaft 5 are engaged, and the front shaft 4 and the rear shaft are engaged. 5 is connected (FIG. 5).
In this state, either when a pulling force is applied in the direction opposite to the connecting direction of the shaft tube so as to remove the rear shaft 5, or when a force is applied in the screwing release rotation direction (circumferential direction of the shaft tube) In this case, the surface portion of the step portion 29 of the front shaft 4 formed perpendicular to the connecting direction of the shaft tube and the vertical surface portion 32 of the convex portion 31 of the rear shaft 5 come into contact with each other. This causes resistance in the direction opposite to the connecting direction. As a result, even if a force acts in the direction in which the front shaft 4 and the rear shaft 5 are detached, the rear shaft 5 does not come out of the front shaft 4, and even if a force acts in the screwing release rotational direction, Is not released, and the front shaft 4 and the rear shaft 5 are securely fixed. If the screw is formed by forcibly removing only by screwing, the contact force between the female screw part and the male screw part may not be obtained sufficiently, and in the case of small parts, It is conceivable that the number of screw threads) is insufficient, but the resistance force of the convex portion 31 of the rear shaft 5 can compensate for the resistance force to the force to pull the rear shaft 5 from the front shaft 4. The front shaft 4 and the rear shaft 5 can be securely fixed.

  In this example, since the slits 34 are formed, variations in the dimensions of the convex portions 31 are absorbed, and the step portions 29 and the convex portions 31 can be reliably engaged with each other with ease of assembly. Further, in this example, as shown in FIG. 2, since the lead tank 13 is inserted into the rear shaft 5 after the front shaft 4 and the rear shaft 5 are screwed together, the slit 34 after the screwing is completed. Inward deformation of the projection 31 and the stepped portion 29 will not be disengaged.

  Next, a second example will be described with reference to FIGS. This example is an example in which the engaging portion is formed so that the engaging portion also contacts in the screwing release rotation direction, that is, the circumferential direction of the shaft tube. Below, the description regarding the structure similar to a 1st example is omitted.

A convex portion 35 is formed on the front end portion of the female screw portion 27 of the front shaft 4 so as to be engaged with the female screw portion 27. As shown in FIG. 11, the convex portions 35 are formed at two positions opposite to each other. As shown in FIG. 11, the convex portion 35 has a triangular cross section and a gradually inclined surface portion 36 that gradually increases in the direction of screw rotation. A steep inclined surface portion 37 that is substantially orthogonal to the inner peripheral surface of the shaft 4 is provided. The surface portion 38 of the convex portion 35 on the connecting direction side of the shaft tube is a surface portion perpendicular to the inner peripheral surface of the front shaft 4, that is, a surface portion perpendicular to the connecting direction of the shaft tube.
On the other hand, a window hole portion (concave portion) 39 is formed on the rear shaft 5 from the front to the rear of the male screw portion 30. Two window hole portions (concave portions) 39 are also formed at opposite positions so as to engage with the convex portions 35.

Next, the operation will be described. As described above, since the convex portion 35 of the front shaft 4 has the gently inclined surface portion 36 that gradually increases in the screwing rotation traveling direction, the rear shaft 5 is screwed to the front shaft 4. At this time, the convex portion 35 of the front shaft 4 is deformed so as to fall in the screwing direction. When the screwing is completed, the convex portion 35 of the front shaft 4 enters the window hole portion 39 of the rear shaft 5, and the convex portion 35 and the window hole portion 39 are engaged.
Here, when a force acts in a direction in which the front shaft 4 and the rear shaft 5 are separated (a direction opposite to the connecting direction of the shaft tube), the female screw portion 27 of the front shaft 4 and the male screw portion 30 of the rear shaft 5. At the same time, and at the same time, two surface portions formed perpendicular to the connecting direction, that is, the surface portion 38 of the convex portion 35 on the connecting direction side of the shaft tube and the front end surface 40 of the window hole portion 39 of the rear shaft 5. And abut. As a result, a resistance force acts against the force to pull out the front shaft 4 and the rear shaft 5 in the direction opposite to the connecting direction of the shaft cylinder, and the rear shaft 5 is prevented from coming off from the front shaft 4 with certainty. I can do it.
Also in this example, even when a force is applied in the screwing release rotation direction, the front end surface of the surface portion 38 on the coupling direction side of the shaft tube and the window hole portion 39 of the rear shaft 5 in the convex portion 35 of the front shaft 4. 40 is abutted so that screwing is not released. In this example, the side surface in the screwing release rotation direction of the convex portion 35 of the front shaft 4, that is, the steep inclined surface portion 37 is connected to the inner side surface 41 of the corresponding window hole portion 39 of the rear shaft 5. Abut. For this reason, a resistance force due to the contact between the convex portion 35 and the window hole portion 39 also works in the screwing release rotation direction (circumferential direction of the shaft tube), so that the screwing is not released. Thereby, the front shaft 4 and the rear shaft 5 can be more securely fixed.

  In this example, the convex portion 35 is formed on the front shaft 4 on which the female screw portion 27 is formed, and the window hole portion 39 is formed on the rear shaft 5 on which the male screw portion 30 is formed, but the four sides are closed as in this example. When the convex portion 35 is engaged with the window hole portion 39, the window hole portion is deformed even if the screwing is forcibly canceled or the shaft tube is strongly pulled in the direction opposite to the connecting direction of the shaft tube. In addition, even if a force is received in the screw release rotation direction (circumferential direction of the shaft tube), the window hole portion receives a force in the expanding direction, so that the outer diameter of the rear shaft is also deformed to expand. However, there is an advantage that the coupling state with the front shaft becomes stronger and difficult to come off. Further, since the convex portion is engaged with the portion surrounded by the four sides, as described above, not only the shaft cylinder is pulled out in the direction opposite to the connecting direction but also locked in the force in the screwing release rotation direction. The force works and the front shaft and the rear shaft can be securely fixed.

Further, in this example, a convex portion is formed on the front shaft on which the female screw portion is formed, and a window hole portion (concave portion) is formed on the rear shaft on which the male screw portion is formed, but a concave portion is formed on the front shaft on which the female screw portion is formed, You may form a convex part in the back axis | shaft which formed the external thread part. In that case, the same effect as this example can be obtained.
In this example, two pairs of convex portions and concave portions are formed, but the number thereof can be selected as appropriate.

  In this example, the convex portion 35 formed on the front shaft 4 is formed on the front end portion of the female screw portion 27 so as to cover the female screw portion. However, as shown in the fourth example, A convex portion may be formed in the vicinity of the front end portion of the screw portion. Further, as shown in the first example, the convex portion may be formed in front of the female screw portion. However, when the convex portion is formed in the vicinity of the front end portion of the screw portion, deformation of the convex portion due to forced removal at the time of molding can be reduced, so that the convex portion and the window hole portion are securely engaged. Can do. In addition, as compared with the case where the screwing portion and the engaging portion are formed apart from each other, the variation in the screwing portion and the engaging portion can be absorbed and reliably engaged. The fixing force by the engaging part can be utilized to the maximum.

  Next, a third example will be described with reference to FIGS. This example is a modification of the second example in which the method of abutment of the convex portion and the window hole portion in the connecting direction of the shaft tube is formed into a key shape.

A convex portion 42 is formed in the vicinity of the front end portion of the female screw portion 27 of the front shaft 4. The vertical cross-sectional shape of the convex portion 42 is arrow-shaped, and has a concave portion 43 with respect to the connecting direction of the shaft tube (FIG. 17). And the cross section of this convex part 42 is square shape, as shown in FIG.
On the other hand, a window hole portion (concave portion) 44 is formed in the rear shaft 5 from the front to the rear of the male screw portion 30. The vertical cross-sectional shape of the front end portion of the window hole portion (recessed portion) 44 has a convex portion 45 that engages with the concave portion 43.

Next, the operation will be described. When the screwing of the front shaft 4 and the rear shaft 5 is completed, the convex portion 42 of the front shaft 4 and the window hole portion 44 of the rear shaft 5 are engaged. At this time, the engaging portion engages so that the concave portion 43 of the convex portion 42 covers the convex portion 45 of the window hole portion 44, so that the rear shaft 5 is detached from the front shaft 4, that is, the shaft Even when a force is applied in the direction opposite to the connecting direction of the cylinders, the front shaft 4 and the rear shaft 5 can be more reliably fixed.
In the case of this example as well, the convex portion 42 of the front shaft 4 and the window hole portion 44 abut on each other in the circumferential direction of the shaft tube. For this reason, even if a force is applied in the screw release rotation direction (circumferential direction of the shaft tube), a resistance force is generated in the direction opposite to the connecting direction of the shaft tube and the screw release release rotation direction. Therefore, in any case, the front shaft 4 and the rear shaft 5 can be securely fixed without being unscrewed and without the rear shaft 5 being detached from the front shaft 4.

Next, a fourth example will be described with reference to FIGS. This example is a modification of the second example in which a plurality of convex portions of the front shaft 4 are formed in series.
A plurality of convex portions 46 are formed near the front end portion of the female screw portion 27 of the front shaft 4. The convex portion 46 has a triangular cross section, a gently inclined surface portion 47 that gradually increases in the direction of threading rotation, and a steep inclined surface portion 48 that is substantially orthogonal to the inner peripheral surface of the front shaft 4. have. The surface portion 49 of the convex portion 46 on the connecting direction side of the shaft tube is a surface portion perpendicular to the inner peripheral surface of the front shaft 4, that is, a surface portion perpendicular to the connecting direction of the shaft tube.

Next, the operation will be described. When the screwing of the front shaft 4 and the rear shaft 5 is completed, the convex portion 46 of the front shaft 4 and the window hole 39 of the rear shaft 5 are engaged. At this time, because of the assembly by screwing, even if there is a variation in the screwing completion position, such a variation can be allowed by providing a plurality of continuous portions as in the convex portion 46 of FIG. is there.
As a result, also in this example, when a force is applied in the direction separating the front shaft 4 and the rear shaft 5, that is, the direction opposite to the connecting direction of the shaft tube, in addition to the female screw portion 27 and the male screw portion 30, The surface portion 49 of the convex portion 46 of the shaft 4 and the surface portion 40 of the window hole portion 39 come into contact with each other to generate a resistance force in a direction opposite to the connecting direction of the shaft tube. Also in the case of this example, the convex portion 46 of the front shaft 4 and the window hole portion 39 also abut on each other in the circumferential direction of the shaft tube. For this reason, even if a force is applied in the screw release rotation direction (circumferential direction of the shaft tube), a resistance force is generated in the direction opposite to the connecting direction of the shaft tube and the screw release release rotation direction. Therefore, in any case, the front shaft 4 and the rear shaft 5 can be securely fixed without being unscrewed and without the rear shaft 5 being detached from the front shaft 4.

Finally, a fifth example will be described with reference to FIGS. Also in this example, the convex portion 50 is formed in the vicinity of the front end portion of the female screw portion 27 of the front shaft 4. An elastic piece 51 is formed on the front shaft 4 by leaving a front portion of the convex portion 50 and cutting out in three directions. By cutting out in this way, the elastic piece portion 51 having the convex portion 50 is adapted to move in the outer diameter direction of the front shaft 4 (outer shaft diameter direction). The surface portion 52 of the convex portion 50 on the connecting direction side of the shaft tube is formed as a surface portion perpendicular to the inner peripheral surface of the front shaft 4, that is, a surface portion perpendicular to the connecting direction of the shaft tube.
The rear shaft 5 has a window hole (concave portion) 39 formed from the front end portion to the rear end portion of the male screw portion 30 as in the second to fourth examples.

Next, the operation will be described. When the front shaft 4 and the rear shaft 5 are screwed together, the convex portion 50 moves outward in the axial diameter of the front shaft 4, so that the elastic piece portion 51 is pushed out so that the convex portion 50 is pushed out of the front shaft 4. Is elastically deformed, and screwing proceeds. The elastic piece portion 51 increases the amount of elastic deformation of the convex portion 50 of the front shaft 4 to make it difficult to damage the rear shaft 5 on which the male screw portion 30 is formed. When the screwing is completed, the convex portion 50 of the front shaft 4 moves inward of the front shaft 4 and enters the window hole portion 39 of the rear shaft 5, and the convex portion 50 of the front shaft 4 and the window of the rear shaft 5 are moved. Engagement with the hole 39 is also completed.
Also in this example, when a force is applied in the direction in which the front shaft 4 and the rear shaft 5 are separated, the female screw portion 27 and the male screw portion 30 abut on each other, and the convex portion 50 of the front shaft 4 The window hole 39 of the rear shaft 5 abuts and generates a resistance force against the force in the direction opposite to the connecting direction of the shaft tube. Further, even if a force is applied in the screwing rotation direction, that is, in the circumferential direction of the shaft cylinder, the convex portion 50 of the front shaft 4 and the window hole 39 of the rear shaft 5 come into contact with each other, and the resistance force in the screwing rotation direction Is generated. For this reason, when a force is applied in the direction in which the front shaft 4 and the rear shaft 5 are disengaged or a force is applied in the screwing release rotation direction, the force in the direction opposite to the connecting direction of the shaft tube And a resistance force against the force in the screw release rotation direction are generated. For this reason, in any case, the front shaft 4 and the front shaft 5 can be reliably fixed without being unscrewed and without the front shaft 5 being removed from the front shaft 4.

  In the case where the elastic piece 51 is provided by cutting out in the three surrounding directions with the front portion of the convex portion 50 left as in this example, the elastic piece portion 51 is It moves in the axial direction using the front part as a fulcrum. When the front shaft 4 is rotated in the screwing release direction after the engagement between the projection 50 and the window hole 39, the projection 50 and the elastic piece 51 having the projection 50 are above the bite, that is, the front Although it deform | transforms toward the back of the axis | shaft 4, it will contact the inner wall of the front axis | shaft 4 eventually, and a deformation | transformation will stop. At this time, the surface portion perpendicular to the connecting direction formed in the convex portion 50 of the front shaft 4 and the window hole portion 39 of the rear shaft 5 is in surface contact and is not deformed outward in the shaft radial direction. For this reason, the engagement of the convex portion 50 with the window hole 39 is not released. With one portion left out of the side portions of the convex portion 50, the convex portion 50 can be deformed in the axial radial direction by cutting out in the three directions around the other side portion, the front portion, and the rear portion. Compared with the case where the convex portion and the window hole portion are engaged once, the convex portion does not move in the axial radial direction after the convex portion and the window hole portion are once engaged. The state can be maintained.

1 shaft cylinder 2 core holding member 3 tip member 4 front shaft (first shaft cylinder)
5 Rear shaft (second barrel)
6 core feeding means 7 chuck body 8 chuck ring 9 core tank 10 ball portion 11 chuck body 12 chuck ring 13 core tank 14 reduced diameter portion 15 step portion 16 step portion 17 repellent member 18 step portion 19 eraser 20 flange portion 21 pressing member 22 concave portion 23 convex portion 24 pressing member cover 25 through hole 26 step portion 27 female screw portion 28 enlarged diameter portion 29 step portion (engagement portion)
30 Male screw part 31 Convex part (engagement part)
32 surface part 33 inclined surface part 34 slit 35 convex part (engagement part)
36 inclined surface portion 37 inclined surface portion 38 surface portion 39 window hole portion (engagement portion)
40 Front end face 41 Inner side face 42 Convex part (engagement part)
43 Concave part (engagement part)
44 Window hole 45 Convex part (engagement part)
46 Convex part (engagement part)
47 Inclined surface portion 48 Inclined surface portion 49 Surface portion 50 Convex portion (engaging portion)
51 elastic piece 52 face part

Claims (4)

The shaft cylinder is formed by connecting the first shaft cylinder and the second shaft cylinder by screwing, and an engaging portion that engages with the convex portion and the concave portion when the screwing is completed is provided in each shaft cylinder , The concave portion is used as a window hole portion, and a surface portion perpendicular to the connecting direction is formed on the engaging side of the engaging portion, and the engaging portion is also applied in the circumferential direction of the shaft tube. A shaft cylinder that is in contact with each other.   The shaft cylinder according to claim 1, wherein either one of the engaging portions is elastically deformable. The shaft cylinder is formed by connecting the first shaft cylinder and the second shaft cylinder by screwing, and an engaging portion that engages with the convex portion and the concave portion when the screwing is completed is provided in each shaft cylinder, The concave portion is a window hole portion, and the vertical cross-sectional shape of the engagement surface of the convex portion with the concave portion is a shape having a concave portion with respect to the connection direction, and the relationship with the convex portion in the concave portion. A shaft cylinder characterized in that a longitudinal cross-sectional shape of a mating surface has a shape having a convex part that engages with the concave part, and the engaging part abuts also in a circumferential direction of the shaft cylinder. The shaft cylinder according to claim 3, wherein any one of the engagement portions is elastically deformable.

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