JP5006110B2 - Writing instrument shaft structure - Google Patents

Description

  The present invention relates to a shaft structure in a writing instrument such as a ballpoint pen or a mechanical pencil.

  Conventionally, as a technique in such a field, there is JP-A-10-287085. The composite writing instrument described in this publication includes an outer cylinder for housing a refill functioning as a mechanical pencil and a refill functioning as a ballpoint pen, and a clip is provided on the outer cylinder. The working cam cylinder protrudes from the rear end of the outer cylinder, and the free end of the working cam cylinder is formed in a cylindrical shape as an eraser receiver, and the cap is detachably attached to the working cam cylinder so as to hide the eraser. . In addition, in a writing instrument that does not employ a mechanical pencil type refill, there is no need for an eraser, so that the cap is fixed to the operating cam cylinder via an adhesive to prevent loss. Further, the rib provided on the operating cam cylinder enters the key groove provided on the inner peripheral surface of the cap, so that the cap is prevented from rotating.

Japanese Patent Laid-Open No. 10-287085 JP 2002-59686 A

  However, in the conventional writing instrument described above, the rib provided on the operating cam cylinder enters the key groove provided on the inner peripheral surface of the cap, thereby preventing the rotation of the cap. The press-fitting and fixing of the cap by cooperating with the key groove is not planned, and this can be inferred from the fact that the key groove is provided on the opening side of the cap. For example, if it is assumed that the rib of the operating cam cylinder is press-fitted into the key groove on the opening side of the cap, a strong force is applied to the cap through the rib. Therefore, the cap has a key groove that is weak in strength. It becomes easy to break at the point of. Therefore, in the case where the conventional writing instrument described above is composed only of a ballpoint pen type refill, it is necessary to fix the cap to the operating cam cylinder with an adhesive, and there is a problem that the assembling workability of the writing instrument is deteriorated. .

  An object of this invention is to provide the shaft structure which contributes to the improvement of the assembly workability | operativity of a writing instrument.

In the shaft structure of the writing instrument in which the cap is attached to the rear end of the shaft tube,
A cylindrical projecting portion is provided at the rear end portion of the shaft cylinder, and a slit extending in the axial direction is provided in the projecting portion, and a slit extending in the axial direction is provided on the inner peripheral surface of the cap. Ribs are inserted into the ribs, and the ribs are press-fitted into the slits.
The inner peripheral surface of the cap is provided with a caulking portion that abuts on the outer wall surface of the protruding portion and narrows the width of the slit .

  In this writing instrument shaft structure, a rib is provided on the cap side, and a slit is provided on the protruding portion on the rear end side of the shaft tube, so that the cap cracks even if the rib is pressed into the slit with a strong force. The cap can be fixed to the rear end portion of the shaft tube with a strong force without using an adhesive. Therefore, the cap may fall off the writing instrument inadvertently when a strong force is applied from the side with the finger or the like while the writing instrument is in use, or when the writing instrument falls on the floor. Can be prevented. When the cap is attached, assembly without an adhesive is possible, thereby improving the workability of the writing instrument. Further, the cap can be prevented from being rotated and positioned by the cooperation of the rib and the slit. As a result, the cap can be easily aligned with the shaft tube.For example, when there are display parts such as characters and pictures on the outer surface of the cap, the position of these display parts and the shaft tube can be aligned during assembly work. No madness will occur. Furthermore, when using the protruding part of the shaft tube as an eraser receiver for accommodating a cylindrical eraser, the slit of the protruding part should be used as a groove for inserting a pin or the like when pushing out the shortened eraser. Can do. Therefore, by forming a slit on the shaft tube side, it is possible to share the shaft tube in both cases of writing tools that use mechanical pencil type refills and writing tools that consist only of ballpoint pen type refills. can do.

Further, on the inner peripheral surface of the cap, it abuts the outer wall surface of the projecting portion that has crimp portion is provided to narrow the width of the slit.
When such a configuration is adopted, the cap can be fixed to the shaft tube with a stronger caulking force with a simple configuration.

The caulking portion preferably includes a first caulking portion formed as a substantially C-shaped belt-like surface extending annularly around the axis.
Thus, since the 1st crimping part is strip | belt shape, the contact area between the surface of a 1st crimping part and the outer wall surface of a protrusion part can be enlarged, and a high frictional force is accompanied. The cap can be fixed to the shaft tube with a strong caulking force.

The caulking part is positioned closer to the opening side of the cap than the first caulking part and is in contact with the outer wall surface of the protrusion, and the cap is closed more than the first caulking part. It is preferable to further include a third caulking portion positioned on the side and abutting against the outer wall surface of the protruding portion.
Thus, by using the second and third caulking parts different from the first caulking part, the cap can be fixed to the shaft tube with a stronger caulking force.

Further, it is preferable that a guide portion narrower than the width of the slit is formed at the opening side end portion of the rib cap.
By adopting such a guide portion, it becomes easy to insert the rib into the slit, and the assembling workability of the writing instrument can be improved.

  According to the present invention, it is possible to improve the assembly workability of the writing instrument.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a writing instrument shaft structure according to the present invention will be described in detail with reference to the drawings. In the following description, the pen tip side is referred to as “front side”.

  As shown in FIG. 1, the writing instrument 1 is a multicolor writing instrument having a ballpoint pen refill of four colors. This knock-type writing instrument 1 includes four ball-point pen-type refills 2, a resin shaft cylinder 3 that accommodates each refill 2, a resin cap 4 attached to the rear end portion of the shaft cylinder 3, and a shaft An openable and closable clip 6 slidable in the direction of the axis L of the cylinder 3 and an anti-slip grip 7 fixed to the shaft cylinder 3 are provided.

  Four guide grooves 8 are formed in the rear portion of the shaft tube 3, and the knock portions 9 slide along the three guide grooves 8 a of the four guide grooves 8, and the tip of each knock portion 9 is , Is inserted into the rear end of the refill 2. The open / close clip 6 is movable in the direction of the axis L along the remaining one guide groove 8 b, and the tip of the slider portion 11 connected to the clip 6 via the U-shaped leaf spring 10 is connected to the refill 2. The slider portion 11 is inserted into the rear end and slides along the guide groove 8b.

  In the writing instrument 1 having such a configuration, by pushing down either the knock portion 9 or the clip 6, the tip of the refill 2 protrudes from the tip of the shaft tube 3, and by pushing down the remaining knock portion 9 or clip 6, the refill The tip of 2 can be stored in the shaft tube 3.

  The shaft cylinder 3 used for such a writing instrument 1 includes a front shaft 3a and a rear shaft 3b. The male screw portion provided on the rear side of the front shaft 3a and the female screw provided on the front side of the rear shaft 3b. The front shaft 3a and the rear shaft 3b are connected by screwing with the part. A grip 7 is fixed to the front shaft 3b.

  Further, as shown in FIG. 2, a cylindrical projecting portion 20 is formed integrally with the shaft tube 3 at the rear end portion of the rear shaft 3b, and the projecting portion 20 extends in the direction of the axis L from the rear end surface. A slit 21 extending in the direction is formed. The cap 4 is fixed to the protruding portion 20.

  Since the writing instrument 1 in this case employs only the ballpoint pen-type refill 2 as a replacement core, it is necessary to prevent the cap 4 from being removed from the shaft tube 3. Further, the cap 4 needs to be fixed to the shaft tube 3 without an adhesive in order to improve the assembly workability.

  Therefore, as shown in FIGS. 3 to 5, an elongated rib 22 that extends in the direction of the axis L and is inserted into the slit 21 is integrally formed on the inner peripheral surface 4 a of the cap 4. And this rib 22 is arrange | positioned in the back of the cap 4 in order to increase intensity | strength, and it is formed so that it may extend in the axis line L direction from the head 4b of the cap 4. As shown in FIG. Further, a guide portion 22a narrower than the width W2 of the slit 21 is formed at the opening side end portion of the cap 4 of the rib 22, and the guide portion 22a makes it easy to insert the rib 22 into the slit 21 in the axis L direction. The assembly workability of 1 is improved. In particular, the rib 22 can be inserted more easily by making the tip of the guide portion 22a a semicircle.

  In this case, press-fitting of the rib 22 into the slit 21 is achieved by making the width W2 of the slit 21 smaller than the width W1 of the rib 22. However, as shown in FIG. 6, even when the width W2 of the slit 21 is slightly larger than the width W1 of the rib 22, the width W2 of the slit 21 can be reduced by the caulking portion 30 described later, As a result, press-fitting of the ribs 22 can be realized.

  Furthermore, the slit 21 is formed corresponding to the guide groove 8b for clip. This is because a display part (for example, “4”) R such as a character or a pattern is decorated on the head 4 b of the cap 4. Therefore, when the rib 22 of the cap 4 is press-fitted into the slit 21 of the protrusion 20, “ This is to prevent the direction of “4” from becoming uneven. Further, by providing the rib 22 at a position corresponding to the top of “4”, when the writing instrument 1 is fastened to the chest pocket by the clip 6, “4” becomes easy to see from the user.

  In such a shaft structure of the writing instrument 1, the rib 22 is provided on the cap 4 side, and the slit 21 is provided in the protruding portion 20 on the rear end side of the shaft tube 3, so that the rib 22 is press-fitted into the slit 21 with a strong force. Even so, the situation where the cap 4 breaks can be avoided, and the cap 4 can be fixed to the rear end portion of the shaft tube 3 with a strong force without using an adhesive. Therefore, the cap 4 is inadvertently detached from the writing instrument 1 when an excessively strong force is applied from the side to the cap 4 while the writing instrument 1 is in use, or when the writing instrument 1 is dropped on the floor. Can be prevented. When the cap 4 is attached, it is possible to perform one-touch assembly without an adhesive, thereby improving the workability of the writing instrument 1.

  Further, the cap 4 can be prevented from rotating and positioned by the cooperation of the rib 22 and the slit 21. Thereby, position alignment of the cap 4 with respect to the axial cylinder 3 can be performed easily. For example, when there is a display portion R such as a character or a picture on the outer surface of the cap 4, there is no possibility that the alignment between the display portion R and the shaft tube 3 will be out of order during assembly work.

  When the protruding portion 20 of the shaft tube 3 is used as an eraser receiver for accommodating the cylindrical eraser A (see FIG. 7), the slit 21 of the protruding portion 20 is a pin or the like when pushing out the shortened eraser A. It can be used as a groove for inserting. Therefore, by forming the slit 21 on the shaft tube 3 side, the writing instrument adopting the mechanical pencil type refill (not shown) and the writing instrument composed only of the ballpoint pen type refill 2 can be used. The shaft cylinder 3 can be shared. Note that a cap (not shown) used for a writing instrument employing a mechanical pencil type refill (not shown) needs to be detachable, so it is made of a material having high elasticity and wear resistance (for example, polypropylene). The rib is not provided.

  When the width W2 of the slit 21 is slightly larger than the width W1 of the rib 22, the inner peripheral surface 4a of the cap 4 is in contact with the outer wall surface of the protruding portion 20 to narrow the width W2 of the slit 21. The caulking portion 30 is provided. The caulking portion 30 includes a first caulking portion 31, a second caulking portion 32, and a third caulking portion 33. With a simple configuration, the cap 4 can be touched with a stronger caulking force. The shaft cylinder 3 can be fixed.

  The first caulking portion 31 is formed as a substantially C-shaped belt-like surface extending annularly around the axis L. The first caulking portion 31 extends from the near side of the rib 22 to the vicinity of the center, and the inner diameter of the first caulking portion 31 is smaller than the outer diameter of the protruding portion 20. Direct and reliable caulking force is exhibited. Moreover, since the 1st crimping part 31 is strip | belt shape, the contact area between the surface of the 1st crimping part 31 and the outer wall surface of the protrusion part 20 can be enlarged, and high frictional force is provided. The cap 4 can be fixed to the shaft tube 3 by the accompanying strong caulking force (see FIG. 6).

  The second caulking portion 32 is positioned closer to the opening side of the cap 4 than the first caulking portion 31 and abuts against the outer wall surface of the protruding portion 20. The second caulking portion 32 is located approximately in the middle between the rib 22 and the end face of the cap 4 and is formed in a convex ring shape with the axis L as the center. The inner diameter of the second caulking portion 32 is smaller than the outer diameter of the protruding portion 20, but is substantially the same as or slightly larger than the inner diameter of the first caulking portion 31.

  The third caulking portion 33 is in contact with the outer wall surface of the protruding portion 20 adjacent to the rear end of the first caulking portion 31 on the closed side (head 4 b side) of the cap 4. The third caulking portion 33 is formed in a convex ring shape around the axis L, and the inner diameter of the third caulking portion 33 is smaller than the inner diameter of the first caulking portion 31.

  In this way, by using the second and third caulking parts 32 and 33 different from the first caulking part 31, the cap 4 is fixed to the protruding part 20 of the shaft tube 3 with a stronger caulking force. Can be made. Moreover, since the 3rd crimping part 33 is provided in the vicinity of the head 4b of the cap 4, the strongest crimping force can be exhibited.

  It goes without saying that the present invention is not limited to the embodiment described above. For example, the first caulking portion 31 may be formed in a convex ring shape around the axis L on the inner peripheral surface 4a of the cap 4, and is a convex portion dotted in the circumferential direction on the inner peripheral surface 4a. May be. The second and third caulking portions 32 and 33 may be substantially C-shaped belt-like surfaces, or may be convex portions scattered in the circumferential direction on the inner peripheral surface 4a.

  Regarding the caulking part 30, it may be any one of the first to third caulking parts 31 to 33, or any combination thereof.

It is a perspective view which shows one Embodiment of the writing instrument which concerns on this invention. It is a perspective view which shows the shaft structure of the writing instrument which concerns on this invention. It is a front view which shows a cap. It is sectional drawing which follows the IV-IV line of FIG. It is a perspective view which shows the rib provided in the cap. It is sectional drawing which shows the state by which a protrusion part is diameter-reduced by a crimping part. It is a perspective view which shows a shaft cylinder and an eraser.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Writing instrument, 3 ... Shaft cylinder, 4 ... Cap, 4a ... Inner peripheral surface of cap, 20 ... Projection part, 21 ... Slit, 22 ... Rib, 22a ... Guide part, 30 ... Clamping part, 31 ... 1st Caulking part, 32 ... second caulking part, 33 ... third caulking part, L ... axis, W1 ... rib width, W2 ... slit width, R ... display part.

Claims (4)

In the writing instrument shaft structure with a cap attached to the rear end of the barrel,
A cylindrical projecting portion is provided at the rear end portion of the shaft cylinder, a slit extending in the axial direction is provided in the projecting portion, and an inner peripheral surface of the cap extends in the axial direction. Then, a rib to be inserted into the slit is provided, and the rib is press-fitted into the slit,
A shaft structure for a writing instrument, wherein a caulking portion is provided on the inner peripheral surface of the cap so as to abut against an outer wall surface of the projecting portion to narrow the width of the slit . The crimp portion, the axis structure of claim 1, wherein the writing instrument, characterized in that it comprises a first caulking portion formed as a substantially C-shaped strip-like surface extending annularly about the axis. The caulking portion is
A second caulking portion that is positioned closer to the opening side of the cap than the first caulking portion and contacts the outer wall surface of the protruding portion;
The writing instrument according to claim 2 , further comprising a third caulking portion that is positioned closer to the cap closing side than the first caulking portion and contacts the outer wall surface of the protruding portion. Shaft structure. The shaft structure of the writing instrument according to any one of claims 1 to 3 , wherein a guide portion narrower than a width of the slit is formed at an opening side end portion of the cap of the rib.

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