JP4409675B2 - Writing instrument cap mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a writing instrument cap mounting structure. Specifically, the present invention relates to a cap mounting structure that includes a first seal portion that is in axial contact with each other and a second seal portion that is in close contact with each other in the radial direction and slidably contacts in the axial direction. In the present invention, “front” refers to the closed side of the cap, and “rear” refers to the open side of the cap.
[0002]
[Prior art]
Conventionally, in a cap mounting structure of a writing instrument (especially a writing instrument that directly stores ink in the writing instrument body), the inside of the cap is pressurized and depressurized by repeatedly attaching and detaching the cap to and from the writing instrument body. In order to prevent ink from leaking out from the pen tip side (ie, the pen tip or the air hole), many proposals have been made.
[0003]
For example, in Japanese Utility Model Laid-Open No. 7-27885, an axially movable inner cap (corresponding to the inner cap of the present invention) is provided inside the outer cap (corresponding to the cap body of the present invention), and the outer peripheral surface of the inner cap is elastic. A packing ring (corresponding to the annular seal portion of the present invention) is provided, the elastic packing ring and the inner surface of the outer cap constitute a first seal location (corresponding to the first seal portion of the present invention), and the outer cap A cap mounting structure for a writing instrument is disclosed in which a second seal portion (corresponding to the second seal portion of the present invention) is formed by an annular ridge portion on the inner surface and an annular ridge portion on the outer surface of the shaft tube.
[0004]
In the conventional writing instrument cap mounting structure, in the cap mounting process, the elastic packing ring is slightly compressed in the axial direction at the first sealing portion, and at the same time, the annular ridges are radially formed at the second sealing portion. It is slidably contacted in the axial direction with slight contact. However, the conventional structure has an axial compression stroke at the first seal location (ie, an axial compression deformation amount of the elastic packing ring) and an axial sliding stroke at the second seal location. However, no consideration is given.
[0005]
Therefore, if the sealing of the first sealing portion is started prior to the second sealing portion in the cap mounting process (that is, when the compression stroke is larger than the sliding stroke), the second sealing portion is Since the sealing in the cap is started simultaneously with the start of the sealing, the air in the cap for the axial sliding contact stroke of the second sealing portion is compressed and the inside of the cap is pressurized. Although the pressurization amount is small, each time the cap is repeatedly attached, the pressurized air flows into the writing instrument body, and finally the ink leaks out from the pen tip side (ie, the pen tip or air hole). There is a risk of causing.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems, and pays attention to the relationship between the axial compression stroke of the first seal portion and the sliding contact stroke of the second seal portion in the axial direction. It is an object of the present invention to provide a writing instrument cap that can sufficiently avoid pressurization in the cap at the time.
[0007]
[Means for Solving the Problems]
[1] In the present invention, the cap body 2 is provided with an inner cap 3 that is urged rearward by the projectile 5 and can be moved back and forth as the writing instrument body 6 advances and retreats. An elastically deformable annular seal portion 41 is provided, and a vent hole 23 is provided on the top surface of the cap body 2. The annular seal portion 41 and the inner peripheral surface of the cap body 2 around the vent hole 23 are axially connected to each other. The first seal portion 8 that is in close contact is configured, and further, the inner peripheral surface of the cap body 2 and the outer peripheral surface of the writing instrument main body 6 are in close contact with each other in the radial direction behind the first seal portion 8. In addition, the second seal portion 9 slidably contacted in the axial direction is configured, and when the cap 1 is mounted on the pen tip 61 side of the writing instrument body 6, the cap 1 is formed by the first seal portion 8 and the second seal portion 9. Writing instrument sealed inside In the cap mounting structure, the axial compression stroke S of the first seal portion 8 from the start of contact between the annular seal portion 41 and the inner peripheral surface of the cap body 2 until the cap mounting is completed, The inner peripheral surface of the cap body 2 and the outer peripheral surface of the writing instrument main body 6 are set to be smaller than the sliding contact stroke T in the axial direction of the second seal portion 9 from the start of the sliding contact until the cap mounting is completed. (Claim 1) is a requirement.
[0008]
(Function)
The axial compression stroke S of the first seal portion 8 (that is, the axial movement length S of the first seal portion 8) is set as the axial sliding stroke T of the second seal portion 9 (that is, the second stroke). The seal portion 9 is made smaller than the axial movement length T), so that the seal of the first seal portion 8 is started before the seal of the second seal portion 9 in the cap mounting process. In addition, when the sealing of the second seal portion 9 is started (see FIG. 3), the first seal portion 8 is not sealed, and the inside of the cap 1 is communicated with the outside via the vent hole 23. Yes. Thereafter, since the sealing of the cap 1 is started simultaneously with the start of the sealing of the first seal portion 8, the second of the axial movement length from the start of the sealing of the first seal portion 8 to the completion of the cap mounting. Due to the sliding movement in the axial direction at the seal portion 9, the air in the cap is slightly compressed. That is, the inside of the cap 1 is slightly pressurized by the axial compression stroke S of the first seal portion 8.
[0009]
Therefore, the sliding contact stroke T in the axial direction of the second seal portion 9 is avoided from being a stroke for pressurizing the inside of the cap 1 as it is, and the amount of compressed air can be reliably reduced. As a result, it is possible to sufficiently prevent the ink from leaking out from the pen tip 61 side (specifically, the pen tip 1 and the air hole 62b).
[0010]
[2] In the cap mounting structure according to the first aspect, it is preferable that the axial compression stroke S of the first seal portion 8 is set smaller than 0.5 mm (Claim 3).
[0011]
(Function)
In the cap mounting structure according to claim 1, since the air in the cap is slightly compressed by at least the compression stroke S in the axial direction of the first seal portion 8, the compression stroke S is specifically defined as follows. By setting it smaller than 0.5 mm, the air compression amount in the cap can actually be reduced, and pressurization in the cap can be further avoided.
[0012]
The smaller the compression stroke S of the first seal portion 8 is, the more advantageous for preventing pressure in the cap. However, in order to obtain a reliable seal in the first seal portion 8, 0.1 mm It is preferable to set a larger value.
[0013]
[3] In the cap mounting structure according to claim 1 or 2, the second seal portion 9 is composed of an annular protrusion 24 on the inner peripheral surface of the cap body 2 and an annular smooth surface 71 on the outer peripheral surface of the writing instrument body 6, Further, behind the second seal portion 9, a ride-over fitting portion comprising an engagement protrusion 25 composed of a plurality of dispersed protrusions on the inner peripheral surface of the cap body 2 and an annular bulging portion 72 on the outer peripheral surface of the writing instrument body 6. 10 is preferable (Claim 3).
[0014]
Since the second seal portion 9 is composed of the annular protrusion 24 and the annular smooth surface 71, a smooth cap mounting property with less sliding resistance and a stable airtight fitting can be obtained, and the ride-over fitting portion 10 A comfortable fit (so-called patching sound) can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0016]
1 to 4 show an embodiment of the writing instrument cap mounting structure of the present invention. FIGS. 1 and 2 show the cap attachment completion state, and FIGS. 3 and 4 show the start of contact of the second seal portion 9 in the cap attachment process.
[0017]
(Writing instrument body)
The writing instrument body 6 includes a nib 61 (here, a ballpoint pen nib), an ink retaining member 62 that retains the nib 61 at the tip, an ink retaining member 62 in the front inside, and the rear of the ink retaining member 62 This is a direct liquid ballpoint pen comprising an axial cylinder 7 that forms an ink tank (not shown) for directly storing ink therein. A cylindrical grip 73 made of an elastic material is disposed on the outer peripheral surface of the front portion of the shaft cylinder 7. Further, an annular smooth surface 71 for airtight fitting and an annular bulging portion 72 for overcoming fitting are integrally formed on the outer peripheral surface of the front end of the shaft cylinder 7 and behind it.
[0018]
The ink holding member 62 is a known member that temporarily holds overflow ink in response to a pressure increase in the ink tank, and a plurality of disc-like comb teeth 62a are provided on the outer peripheral surface. The ink retaining member 62 is provided with an air hole 62 b communicating with the ink tank in the shaft cylinder 7. The air hole 62 b communicates with the inside of the ink tank behind the ink holding member 62.
[0019]
(cap)
The cap 1 mainly includes a cap body 2, an inner cap 3 that is accommodated in the cap body 2 so as to be movable in the axial direction and biased rearward by the projectile 5, and an elastic provided at the front end of the inner cap 3. It consists of a deformable annular seal portion 41 and a clip 11 attached to the outer surface of the cap body 2.
[0020]
(Cap body)
The cap body 2 is formed of a bottomed cylindrical body in which a closing wall 21 at the front end and a cylindrical side wall 22 are integrally provided and the lower end is opened, and is obtained by injection molding of a synthetic resin (for example, polypropylene resin). It is done. A vent hole 23 is provided in the center of the closing wall 21 of the cap body 2 in the axial direction. On the inner surface of the blocking wall 21 around the vent hole 23, an annular flat surface on which the annular seal portion 41 can be in close contact is formed.
[0021]
On the inner peripheral surface of the cap main body 2, an annular protrusion 24 that hermetically fits (seals) the outer peripheral surface (that is, the annular smooth surface 71) of the writing instrument body 6 on the opening side, and an annular bulge of the writing instrument main body 6 on the rear side. Engagement protrusions 25 (specifically, a plurality of dispersed protrusions) that fit over the portion 72 are integrally formed. Further, a retaining protrusion 26 (specifically, a plurality of dispersed protrusions) is provided on the inner peripheral surface of the cap main body 2 in front of the annular protrusion 24 to contact the lower end of the inner cap 3 to prevent the inner cap 3 from falling off. ) Are integrally formed. Further, a plurality (three in this case) of axial spring receiving ribs 27 are integrally projected on the inner peripheral surface of the bottom of the cap body 2.
[0022]
Further, a cutout communication groove 29 extending in the radial direction is formed on the front surface of the blocking wall 21 around the vent hole 23 of the cap body 2. Further, the communication groove 29 passes through the insertion leg portion 11 a of the clip 11. Thereby, it is avoided that the vent hole 23 is blocked with a finger or palm when the cap is attached.
[0023]
(Inner cap)
The inner cap 3 is a cylinder whose rear end is open. The side wall of the inner cap 3 has a flange portion 31 for receiving the elastic body 5 (specifically, a compression coil spring) accommodated in the cap body 2 and a plurality of (here, the inside and outside of the inner cap 3). 4) window holes 32 are formed. An elastic seal body 4 (annular seal portion 41) is attached to the front end of the inner cap 3. The inner cap 3 is urged rearward by a projectile 5.
[0024]
(Elastic seal body)
The elastic seal body 4 is a molded member made of an elastic material (for example, synthetic rubber), and is a bottomed cylindrical body having a front end opened and a rear end closed. The elastic seal body 4 is integrally formed with an annular seal portion 41 that closes the air hole 23 in close contact with the inner surface of the closing wall 21 of the cap body 2 at the front end, and contacts the pen tip 61 at the rear end. A nib seal portion for sealing the nib 61 is integrally formed.
[0025]
(First seal part)
The first seal portion 8 includes an annular seal portion 41 made of an elastic material and an inner surface around the vent hole 23 of the cap body 2 (that is, an annular flat surface on the inner surface of the blocking wall 21). In addition to the above configuration, for example, the first seal portion 8 is provided with the annular seal portion 41 on the outer peripheral surface of the intermediate portion of the inner cap 3, and the annular seal portion 41 is provided on the cap body 2 behind the vent hole 23. The structure which made it possible to closely contact with the conical surface of the inner surface may be used. In this embodiment, the compression stroke S of the first seal portion 8 is specifically set to 0.35 mm.
[0026]
(Second seal part)
The second seal portion 9 includes an annular protrusion 24 on the inner peripheral surface of the cap body 2 and an annular smooth surface 71 on the outer peripheral surface of the shaft cylinder 7. In addition to the combination of the annular protrusion 24 and the annular smooth surface 71, the configuration of the second seal portion 9 is, for example, a combination of an annular smooth surface and an annular smooth surface, or a combination of an annular protrusion and an annular protrusion. Also good.
[0027]
The sliding contact stroke T of the second seal portion 9 is preferably greater than 0.5 mm in consideration of manufacturing variations of the cap body 2 and the shaft tube 7. In this embodiment, the sliding contact stroke T of the second seal portion 9 is set to 0.6 mm.
[0028]
(Override fitting part)
The crossover fitting portion 10 is configured by an annular bulging portion 72 on the outer peripheral surface of the shaft cylinder 7 and an engagement protrusion 25 on the inner peripheral surface of the cap body 2.
[0029]
(Function)
The cap mounting process (from the start to the end of cap mounting) will be described in order according to [1] to [4] below.
[0030]
[1] Cap Installation Start When the pen tip 61 side of the writing instrument body 6 is inserted into the cap 1, the shoulder 74 at the rear of the pen tip 61 of the writing instrument body 6 is a locking wall formed by a plurality of vertical ribs on the inner surface of the inner cap 3. The inner cap 3 is moved forward in the cap main body 2 as the writing instrument main body 6 moves forward.
[0031]
[2] Start sealing of the second seal portion (see FIGS. 3 and 4)
Next, in the cap mounting process, when the annular protrusion 24 on the inner peripheral surface of the cap body 2 and the annular smooth surface 71 on the outer peripheral surface of the writing instrument body 6 start sliding contact (that is, the second seal portion 9 starts sealing). The annular seal portion 41 of the inner cap 3 and the inner surface (annular plane) of the blocking wall 21 around the vent hole 23 are still in a non-contact state. Therefore, the front side of the second seal portion 9 in the cap body 2 communicates with the outside through the window hole 32 of the inner cap 3 and the vent hole 23 of the cap body 2.
[0032]
[3] Start of sealing of the first seal portion and contact between the annular seal portion 41 and the inner surface of the cap body 2 in the sliding contact process of the second seal portion 9 (that is, compression of the annular seal portion 41 in the axial direction). Starts. That is, the sealing of the first seal portion 8 starts. Thereby, sealing in the cap 1 is started.
[0033]
[4] Cap installation complete (see Figs. 1 and 2)
Thereafter, the first seal portion 8 is compressed by the axial movement length S, and at the same time, the second seal portion 9 is also in sliding contact with the axial movement length S in the axial direction. The fitting projection 25 is fitted over the annular bulging portion 72 on the outer surface of the writing instrument main body 6 and the front end portion of the shaft cylinder 7 and the step portion 28 on the inner surface of the cap main body 2 come into contact with each other, whereby the cap mounting is completed. . The amount of compressed air in the cap is the sliding contact length in the axial direction of the second seal portion 9 after the first seal portion 8 starts sealing (that is, the sliding contact stroke in the axial direction of the second seal portion 9). It is set to be extremely small by the compression stroke S) in the axial direction of the first seal portion 8 which is smaller than T.
[0034]
【The invention's effect】
According to the configuration of the first aspect, it is possible to sufficiently avoid pressurization in the cap when the cap is mounted, and as a result, it is possible to sufficiently prevent the ink from leaking out from the pen tip side.
[0035]
According to the configuration of the second aspect, the air compression amount in the cap can be actually reduced, and pressurization in the cap can be further avoided.
[0036]
According to the configuration of claim 3, a smooth cap mounting property with less sliding resistance and a stable airtight fitting can be obtained, and a comfortable fitting feeling can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a cap mounting completion state of an embodiment of the present invention.
2A is an enlarged view of a portion A (first seal portion) in FIG. 1, and FIG. 2B is an enlarged view of a portion B (second seal portion) in FIG.
FIG. 3 is a longitudinal sectional view showing a process of attaching the cap of FIG.
4A is an enlarged view of a C portion (first seal portion) in FIG. 3, and FIG. 4B is an enlarged view of a D portion (second seal portion) in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cap 11 Clip 11a Inserting leg part 2 Cap main body 21 Closure wall 22 Side wall 23 Vent hole 24 Annular protrusion 25 Engaging protrusion 26 Retaining protrusion 27 Spring receiving rib 28 Step part 29 Communication groove 3 Inner cap 31 Eave part 32 Window hole 33 Locking wall 4 Elastic seal body 41 Annular seal part 5 Elastic body 6 Writing instrument body 61 Pen tip 62 Ink retaining member 62a Disk-like comb tooth 62b Air hole 7 Shaft cylinder 71 Annular smooth surface 72 Annular bulging part 73 Grip 74 Shoulder portion 8 First seal portion 9 Second seal portion 10 Overpass fitting portion S First seal portion axial compression stroke T Second seal portion axial sliding contact stroke

Claims (3)

In the cap body, an inner cap that is urged rearward by a projectile body and is movable back and forth as the writing instrument body moves forward and backward is provided, and an annular seal portion that is elastically deformable is provided on the outer surface of the inner cap and the cap A vent hole is provided on the top surface of the main body, and the annular seal portion and the inner peripheral surface of the cap main body around the vent hole constitute a first seal portion closely contacting each other in the axial direction, and the first seal A second seal portion that is in close contact with each other in the radial direction and slidably contacts in the axial direction is formed by the inner peripheral surface of the cap body and the outer peripheral surface of the writing instrument body at the rear of the part, and the cap is a pen tip of the writing instrument body A writing instrument cap mounting structure in which a cap is hermetically sealed with the first seal portion and the second seal portion when mounted on the side, the annular seal portion and the cap body inner peripheral surface, The axial compression stroke of the first seal portion from the start of contact until the cap mounting is completed is the same as the cap mounting after the cap body inner peripheral surface and the writing instrument main body outer peripheral surface start sliding contact. A writing instrument cap mounting structure, which is set to be smaller than the axial sliding contact stroke of the second seal portion until completion. 2. The writing instrument cap mounting structure according to claim 1, wherein an axial compression stroke of the first seal portion is set to be smaller than 0.5 mm. The second seal portion includes an annular protrusion on the inner peripheral surface of the cap body and an annular smooth surface on the outer peripheral surface of the writing instrument main body, and a plurality of dispersions of the inner peripheral surface of the cap body at the rear of the second seal portion. 3. The writing instrument cap mounting structure according to claim 1 or 2, further comprising a crossover fitting portion comprising an engaging protrusion made of a protrusion and an annular bulging portion on the outer peripheral surface of the writing instrument body.

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