JP2011156811A - Composite writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite writing utensil capable of easily coupling together a tip shaft and a middle shaft by a strong coupling force without using any separate metal fitting cylinder, and suppressing wearing-out. <P>SOLUTION: The composite writing utensil includes a middle shaft 4 disposed between a tip shaft 2 and a rear shaft 3, fitted and bonded to the tip shaft 2 so as to be detachable and to the rear shaft 3 so as to be rotatable and movable in an axial direction, and configured to connect the tip shaft 2 and the rear shaft 3 so that they are relatively rotatable. The middle shaft 4 is integrally formed of a resin material. Slits 7 and 8 are formed in the fitting part of the middle shaft 4 and the tip shaft 2. Lock ribs extending in a plurality of peripheral directions are formed on both sides of the slits 7 and 8, in positions for equally dividing the slits 7 and 8 in the axial direction. In the inner peripheral surface of the tip shaft 2, a removal stop from the rear shaft and the tip shaft 2 is constituted by a lock groove 14 to lock the lock ribs. A plurality of rotation stop ribs are integrally formed behind the lock ribs. By a rotation stop groove serially formed behind the lock groove 14, removal and rotation are simultaneously prevented in the coupled state of the middle shaft 4 and the tip shaft 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a composite writing instrument provided with a plurality of writing shaft bodies, and more particularly to a composite writing instrument characterized by a connecting structure of a middle shaft and a front shaft interposed between a front shaft and a rear shaft.

  In a conventional composite writing instrument, it is interposed between the front shaft and the rear shaft, is detachably fitted to the front shaft, and is fitted and coupled to the rear shaft so as to be rotatable and axially movable. A middle shaft for connecting the front shaft and the rear shaft so as to be relatively rotatable, and a plurality of writing shaft bodies inserted into the middle shaft are selectively protruded from the front shaft tip by the relative rotation of the front shaft and the rear shaft. What is made into the structure made to retreat is known (for example, refer patent documents 1, 2).

  In the composite writing instrument of Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-328393) relating to the application of the present applicant, the rear part of the middle shaft is used as the rear shaft as a connecting means between the middle shaft interposed between the front shaft and the rear shaft. The front shaft and the rear shaft are connected to each other so as to be rotatable relative to each other by screwing a front projecting portion of the middle shaft projecting from the front end of the rear shaft into the front shaft.

  Similarly, in the composite writing instrument of Patent Document 2 relating to the application of the present applicant, a fitting cylinder is separately used as a connecting means between the guide cylinder corresponding to the central shaft and the front shaft, and the guide is guided from the rear into the fitting cylinder. By caulking the fitting tube to the guide tube with the front part of the tube inserted, and fitting the front projecting portion of the fitting tube protruding from the tip of the rear shaft into the front shaft in a detachable manner The front shaft and the rear shaft are connected so as to be relatively rotatable. Here, the fitting tube is made of metal, and the guide tube is made of resin, and the fitting tube made of metal is fitted with the front shaft. A fitting dowel is formed at the mating site, and consideration is given to increasing the fitting force with the tip shaft.

JP 2001-328393 A (page 3, column 4, lines 10 to 18, line 1) Japanese Patent Laying-Open No. 2005-161829 ([0023], FIGS. 1 and 2)

  The conventional composite writing instrument is configured as described above, and as a means for connecting the front shaft and the central shaft, in the composite writing tool of Patent Document 1, the front projecting portion of the middle shaft with the rear portion inserted and fixed to the central shaft is screwed into the front shaft. As a result of this structure, the front and middle shafts must be engraved with screws for screwing them together. To engrave the screws, the thickness of the front and middle shafts must be increased. Therefore, there has been a problem that each shaft diameter becomes thick. Moreover, since positioning of the front axis and the rear axis is necessary, there is a problem that it takes time to align the positions. Furthermore, in order to obtain the effect of retaining the center shaft as a molded product and preventing it from coming off at the same time, only the configuration in which screws are provided on the center shaft and the front shaft as in Patent Document 1 has been known as the prior art.

  On the other hand, in the composite writing instrument of Patent Document 2, the guide cylinder corresponding to the middle shaft is provided so that the shaft diameter is thin, the same retaining effect and anti-rotation effect can be achieved, and mounting can be performed with one touch that does not require alignment. As a means for connecting the front shaft and the front shaft, a metal fitting cylinder must be used separately, which increases the number of components and complicates the structure. In addition, the metal dosing cylinder is formed with a fitting dowel at the fitting portion with the tip shaft so as to increase the fitting force with the tip shaft, but the fitting dowel causes “sagging”. There was a problem that it was easy.

  Therefore, a slit facing the fitting portion of the resin middle shaft with the tip shaft is provided, and so-called two-point fitting ribs each addressed to the center portion of the wall portion of the middle shaft divided by the slit are provided, and the resin Forcibly punching and forming the front shaft made of the product, locking the locking groove by the undercut to the inner diameter portion of the front shaft, and tried to lock the locking rib in the locking groove, The locking force between the locking rib and the locking groove was weaker than expected, and a sufficient coupling force between the front shaft and the middle shaft could not be obtained.

  The present invention has been made to solve the above-described problems, and can easily lock the front shaft and the middle shaft with sufficient coupling force without requiring a separate metal fitting cylinder. In addition, an object is to provide a composite writing instrument that can reduce costs by reducing the number of parts and that can suppress “sagging”.

  The composite writing instrument according to the present invention is interposed between the front shaft and the rear shaft, is detachably fitted to the front shaft, and is fitted to the rear shaft so as to be rotatable and axially movable. A middle shaft coupled to the front shaft and the rear shaft so that the front shaft and the rear shaft can be rotated relative to each other; and a plurality of writing shaft bodies inserted into the middle shaft are selectively selected from the front end of the front shaft by relative rotation of the front shaft and the rear shaft. In the projecting / retracting composite writing instrument, a slit extending in the axial direction is provided at a position where the center part is bisected in the radial direction, and a slit extending in the axial direction is provided at the part where the center shaft is engaged with the tip shaft. A plurality of locking ribs extending in the circumferential direction are integrally formed adjacent to both sides of the slit at a position that equally bisects the shaft in the axial direction, and the locking rib is locked to the inner peripheral surface of the front shaft. A groove prevents the rear shaft from coming off from the front shaft, and extends behind the locking rib in the axial direction. A plurality of non-rotating ribs are integrally formed, and the retaining shaft is coupled with the center shaft and the front shaft by a non-rotating groove formed in series behind the locking groove for locking the non-rotating rib. At the same time, a detent can be realized.

  The said locking groove of the composite writing instrument which concerns on this invention consists of an annular inner groove formed in the internal peripheral surface of a front axis | shaft.

  According to the composite writing instrument of the present invention, the resin middle shaft is fitted to the front shaft, so that a metal fitting cylinder is not required separately from the middle shaft, and the number of parts can be reduced and the cost can be reduced. There is. In particular, in the composite writing instrument of the present invention, the slit extending in the axial direction opposite to the portion that bisects in the radial direction at the fitting portion with the front shaft in the resin-made central shaft, and the slit extending in the axial direction By providing a plurality of locking ribs extending in the circumferential direction at the dividing position, the locking rib of the middle shaft is pushed evenly toward the center of the middle shaft on the inner diameter surface of the front shaft when the middle shaft is fitted to the front shaft. And, at this time, the wall portion of the central shaft is smoothly bent in the inner diameter direction by the slit, so that there is an effect that “sagging” of the locking rib of the central shaft can be suppressed. Further, when the locking rib of the middle shaft reaches the locking groove on the inner diameter surface of the front shaft, the wall between the slits of the middle shaft is elastically restored in the outer diameter direction, so that the locking rib becomes the locking groove. By securely engaging, there is an effect that a sufficient coupling force between the front shaft and the middle shaft can be obtained.

  According to the composite writing instrument of the present invention, since the locking groove of the front shaft is composed of an annular inner groove formed on the inner peripheral surface of the front shaft, the locking groove of the front shaft can be simply inserted into the front shaft. Further, there is an effect that the locking rib of the middle shaft can be easily locked.

Embodiment 1 FIG.
1 is a sectional view showing a composite writing instrument according to Embodiment 1 of the present invention, FIG. 2 is a sectional view showing a front axis of the composite writing instrument of FIG. 1, FIG. 3 is a right end view of FIG. 2, and FIG. 5 is a side view of FIG. 4, FIG. 6 is a sectional view taken along line BB in FIG. 5, FIG. 7 is a sectional view taken along line AA in FIG. 4, and FIG. C line sectional view, FIG. 9 is a DD line sectional view of FIG.

  The composite writing instrument shown in FIG. 1 is interposed between a shaft cylinder 1, a cylindrical front shaft 2 and a rear shaft 3 constituting the shaft cylinder 1, and is detachably fitted to the front shaft 2. And a cylindrical middle shaft (not shown) that is rotatably coupled to the rear shaft 3 so as to be movable in the axial direction and connects the front shaft 2 and the rear shaft 3 so as to be relatively rotatable and immovable in the axial direction. A plurality of writing shaft bodies 5 (only one mechanical pencil core pipe is shown in FIG. 1) inserted in the middle shaft 4 and urged in the backward direction are provided on the front shaft 2. And a structure in which the rear shaft 3 is selectively projected and retracted from the tip of the front shaft 2 by relative rotation of the rear shaft 3.

  The central shaft 4 is entirely formed of a resin material, and an insertion hole 6 (see FIGS. 6 and 9) for inserting a plurality of writing shaft bodies 5 is provided in the inner partition wall of the central shaft 4. Further, an annular flange (stopper) 6 is provided on the outer diameter surface of the middle shaft 4 closer to the front side than the intermediate portion in the axial direction, and the middle shaft 4 is separated from the front cylinder portion 4a and the rear cylinder by the flange portion 6. The front cylinder part 4a is a fitting part that is detachably fitted to the front shaft 2 and is partitioned by the part 4b, and the rear cylinder part 4b is a fitting part for the rear shaft 3. ing.

  In such an intermediate shaft 4, the front portion of the front tube portion 4 a serving as a fitting portion with the front shaft 2 is opposed to the front tube portion 4 a at a position where the front tube portion 4 a is bisected in the radial direction and extends in the axial direction 2. Two slits 7 and 8 are provided. Also, four locking ribs 9 to 12 are integrally formed on the outer peripheral wall portion of the central shaft 4 between the slits 7 and 8 so as to protrude in the direction of dividing the wall portion into four and extend in the circumferential direction. Further, the rear outer peripheral surfaces of the slits 7 and 8 and the locking ribs 9 to 12 in the front cylindrical portion 4a (the outer peripheral surface of the central shaft 4 between the slits 7 and 8 and the locking ribs 9 to 12 and the flange portion 6). A plurality of detent ribs 13 extending in the axial direction are provided at predetermined intervals in the circumferential direction.

  On the other hand, on the inner diameter surface of the front shaft 2, as shown in FIG. 2, a locking groove 14 for locking the locking ribs 9 to 12 of the middle shaft 4 and a detent rib 13 for the middle shaft 4 are locked. An anti-rotation groove 15 is provided, and the locking groove 14 is an annular inner groove formed on the inner peripheral surface of the front shaft 2, and the anti-rotation groove 15 is also formed on the inner peripheral surface of the front shaft 2. It consists of an axial groove.

  Here, the plurality of writing shaft bodies 5 mean one mechanical pencil core pipe 5a and two ballpoint pen refills (not shown) having different ink colors in the illustrated example. A refill joint 16 (see FIG. 1) for inserting and connecting the rear part of the refill (not shown) of the ballpoint pen is inserted into two of the three insertion holes 6 of the central shaft 4. A lead feeding mechanism 18 is connected to a front portion of the lead pipe 5a of the mechanical pencil via a chuck joint 17, and the lead pipe 5a is urged rearward by a return spring 19. The refill connected to the refill joint 16 is also urged rearward by the return spring 20.

  Inside the rear shaft 3 is a cam mechanism 21 for alternately projecting and retracting a plurality of writing shaft bodies 5 from the tip of the front shaft 2 by rotating the rear shaft 3 with respect to the front shaft. Is provided. A clip 22 and an eraser cradle 23 are attached to the rear portion of the rear shaft 3, and an eraser 24 is fitted on the eraser cradle 23 and covered with an eraser cover 25. Further, a body ring 26 that covers an exposed portion of the middle shaft 4 is fitted between the front end of the rear shaft 3 and the rear end of the front shaft 2 at the front portion of the rear shaft 3.

Next, the operation when the middle shaft 4 is connected to the front shaft 2 will be described.
The rear cylinder portion 4b of the middle shaft 4 is fitted into the rear shaft 3 so as to be rotatable relative to the rear shaft 3 but not axially movable. In this state, the front cylinder portion 4a of the middle shaft 4 is fitted into the front shaft 2. When fitted from the rear, the locking ribs 9 to 12 of the middle shaft 4 are slidably contacted with the inner diameter surface of the front shaft 2 and pushed in the inner diameter direction, so that the peripheral wall portion in the vicinity of the formation region of the locking ribs 9 to 12 on the middle shaft 4 Is bent in the inner diameter direction at the formation site of the slits 7 and 8. Due to the bending, the middle shaft 4 can be easily inserted into the front shaft 2, and by the insertion, the rotation prevention rib 13 of the middle shaft 4 is engaged with the rotation prevention groove 15 of the front shaft 2. When the retaining ribs 9 to 12 reach the retaining groove 14 of the front shaft 2, the wall portion of the formation region of the retaining ribs 9 to 12 in the middle shaft 4 is elastically restored in the outer diameter direction. The locking ribs 9 to 12 of the middle shaft 4 are securely locked to the groove 14. Thereby, the front shaft 2 and the rear shaft 3 are connected so as to be relatively rotatable.

  According to the first embodiment described above, since the resin middle shaft is fitted to the front shaft, the middle shaft 4 and the front shaft 2 are connected without the need for a metal fitting cylinder separately from the middle shaft 4. Thus, there is an effect that the number of parts is reduced and the cost can be reduced. In particular, by providing two slits 7 and 8 and four-point locking ribs 9 to 12 at the axial target position at the fitting portion of the resin middle shaft 4 with the tip shaft 2, the center shaft 4 with respect to the tip shaft 2 is provided. At the time of fitting, the four locking ribs 9 to 12 of the middle shaft 4 are pushed evenly toward the center of the middle shaft 4 on the inner diameter surface of the front shaft 2, and at this time, the middle shaft 4 is pushed by the slits 7 and 8. Since the wall portion of the inner shaft 4 smoothly bends in the inner diameter direction, there is an effect that it is difficult for the locking ribs 9 to 12 of the central shaft 4 to be “spotted”. In addition, when the locking ribs 9 to 12 of the middle shaft 4 reach the locking groove 14 on the inner diameter surface of the front shaft 2, the wall portion of the bent portion of the middle shaft 4 is elastically restored in the outer diameter direction, thereby causing the engagement. The retaining ribs 9 to 12 can be reliably locked in the locking groove 14, thereby providing an effect that a sufficient coupling force between the front shaft 2 and the middle shaft 4 can be obtained.

  Further, in the composite writing instrument according to Embodiment 1 of the present invention, the locking groove 14 of the front shaft 2 is an annular inner groove formed on the inner peripheral surface of the front shaft 2, so that the middle shaft 4 is inserted into the front shaft 2. Only by doing this, there is an effect that the locking ribs 9 to 12 of the middle shaft 4 can be easily locked in the locking groove 14 of the tip shaft 2. Furthermore, since the detent rib 13 formed on the outer diameter surface of the middle shaft 4 is engaged with the detent groove 15 formed on the inner diameter surface of the front shaft 2, the relative rotation between the front shaft 2 and the middle shaft 4 can be suppressed. effective.

It is sectional drawing which shows the composite writing instrument by Embodiment 1 of this invention. It is sectional drawing which shows the front axis | shaft of the composite writing instrument of FIG. FIG. 3 is a right end view of FIG. 2. It is a top view which shows the center axis | shaft in FIG. FIG. 5 is a side view of FIG. 4. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is the sectional view on the AA line of FIG. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG.

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Lead shaft 3 Rear shaft 4 Middle shaft 5 Writing shaft body 5a Core pipe 6 鍔 part 7, 8 Slit 9-12 Lock rib 13 Lock rib 14 Lock groove 15 Lock groove 16 Refill joint 17 Chuck joint 18 Core feeding mechanism 19, 20 Return spring 21 Cam mechanism 22 Clip 23 Eraser cradle 24 Eraser 25 Eraser cover

Claims (2)

The front shaft and the rear shaft are interposed between the front shaft and the rear shaft, are detachably fitted to the front shaft and are fitted and coupled to the rear shaft so as to be rotatable and axially movable. In a composite writing instrument that includes a middle shaft that is coupled so as to be relatively rotatable, and that a plurality of writing shaft bodies inserted into the middle shaft are selectively projected and retracted from the front shaft tip by relative rotation of the front shaft and the rear shaft. ,
A position at which the slit is extended in the axial direction opposite to the position at which the fitting portion is bisected in the radial direction and a position at which the slit is bisected in the axial direction is provided at the fitting portion of the middle shaft with the tip shaft A plurality of locking ribs extending in the circumferential direction are integrally formed adjacent to both sides of the slit, and a locking groove for locking the locking rib is formed on the inner peripheral surface of the front shaft from the front shaft of the rear shaft. A stopper is configured, and a plurality of axially extending anti-rotation ribs are integrally formed at the rear of the locking rib, and the rotation is formed in series behind the locking groove for locking the anti-rotation rib. A composite writing instrument characterized in that the retaining groove prevents the rotation simultaneously with the retaining while the middle shaft and the front shaft are coupled.   2. The composite writing instrument according to claim 1, wherein the locking groove is an annular inner groove formed on the inner peripheral surface of the front shaft.

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