JP7108525B2 - thermochromic writing instrument - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermochromic writing instrument capable of thermally discoloring handwriting by rubbing the handwriting of thermochromic ink and generating frictional heat.

Conventionally, a thermochromic writing instrument has a friction body at the end of a shaft body such as a barrel body or a cap body that constitutes the writing instrument, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-206432). There are many things that are installed to improve convenience.
The friction body of the thermochromic writing instrument is made of an elastic material (rubber, elastomer) and reciprocates while being pressed against the paper surface, so it must be firmly fixed to the rear end of the shaft. In addition, when the friction body is fixed to the crown attached to the barrel, such as those with a tail crown on the rear end of the barrel body, or those with a head crown on the front end of the cap body, the crown body It is necessary to firmly fix the friction body to the shaft and to fix the crown firmly to the shaft.

As a method for fixing the crown to the shaft, screwing, fitting, adhesion, or the like is generally used. A structure in which the crown is fixed to the shaft by fitting is widely used because it is easy to assemble. In many cases, it is often necessary to increase the fitting force by increasing the lap margin between the members at the time of fitting in advance. However, if the lap margin of the fitting portion is increased simply to increase the fitting force, the advantage of assembling by fitting is lost in that assembly becomes difficult. If the body is made of metal or hard resin, it is difficult to deform the members during fitting, resulting in poor assembly.

Japanese Patent Application Laid-Open No. 2003-206432

In the present invention, a thermochromic writing instrument in which a crown is attached to the end of a shaft and a friction body is attached to the crown is easy to assemble and has a thermochromic structure in which the crown is difficult to fall off. The purpose was to obtain writing instruments.

The present invention
"1. A thermochromic writing instrument capable of thermally discoloring the handwriting by rubbing the handwriting of the thermochromic ink and by the frictional heat generated at that time,
A shaft having an opening at its end, a cylindrical crown inserted into the opening of the shaft, and a friction body inserted into the crown,
A plurality of protrusions are formed on the side wall of the crown body and engage with the protrusions formed on the inner surface of the shaft when the crown body is inserted into the shaft body. A plurality of windows extending in a direction along the axis of the shaft is provided,
A stop plug is attached to the inner end of the crown and a friction body is attached to the outer end of the crown, so that the side wall of the crown bends toward the center of the crown. A thermochromic writing instrument characterized by preventing
2. The window portion has an elongated hole shape, and the outer surface of the stop plug is in contact with the inner surface of the crown body inside the maximum diameter portion of the semicircle on the inner end side of the elongated hole-shaped window portion,
2. The thermochromic writing instrument according to item 1, wherein the outer surface of the friction body is in contact with the inner surface of the crown body inside the maximum diameter portion of the semicircle on the outer end side of the elongated hole-shaped window. ”.

In the present invention, when the barrel is the barrel main body, the side where the nib is located (front) is referred to as the inside, and the opposite side is referred to as the outside. In other words, the direction in which the tail is located is the outside.
In addition, when the barrel is a cap, the side (rear) of the barrel main body where the pen tip is inserted is referred to as the inner side, and the opposite side is referred to as the outer side. In other words, the direction in which the crown is located is the outside.
According to the present invention, when a crown such as a tail crown or a crown is inserted into a shaft such as a barrel body or a cap body during assembly, the direction along the axis formed in the crown is As a result, when the plurality of projections provided on the side wall get over the projections formed on the inner surface of the shaft body, the side wall of the crown body moves inward in the axial radial direction. By bending it in the direction, it becomes easier to insert it into the shaft.

In addition, by inserting a stop plug at the inner end of the crown and inserting a friction member at the outer end of the crown, the side wall of the crown is prevented from being bent inward, thereby The crown is firmly fixed. Therefore, it is possible to prevent the crown from coming off when the friction body rubs against the assembled thermochromic writing instrument.
If the side wall of the crown can be deflected toward the center of the crown simply by inserting a stop plug or a friction body at only one of the ends of the crown. , inserting the crown into the shaft with a stop plug inserted into the inner end of the crown positioned at the back of the shaft, and then attaching the friction body to the crown inserted into the shaft. By inserting the , it becomes easy to assemble.

The material of the shaft is brass, aluminum, polycarbonate resin, PMMA resin (polymethyl methacrylate), acrylonitrile styrene resin, ABS resin (acrylonitrile-butadiene-styrene copolymer), polypropylene resin, etc. Materials conventionally used for the cap body may be used, but are not particularly limited.
Materials similar to those of the shaft described above can be used for the material of the crown and stop plug.
The windows formed in the side walls of the crown are elongated, elliptical, or otherwise shaped so that the holes extend in the direction along the axis. It becomes easy to bend toward the center direction.
The material of the friction body is preferably an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer). ), fluorine-based resin, chloroprene resin, nitrile resin, polyester-based resin, ethylene propylene diene rubber (EPDM), and the like.
The hardness of the friction body is preferably Shore A hardness of 40 or more and 100 or less. More preferably, the Shore A hardness is 60 or more and 80 or less so as to prevent bending in the direction. The thickness of the friction body is set to a thickness that prevents the side wall of the crown from bending toward the center of the crown when it is inserted into the crown.

Furthermore, the window portion of the side wall of the crown is elongated, and the outer surface of the stopper is in contact with the inner surface of the crown inside the maximum outer diameter of the semicircle on the inner end side of the elongated window, The outer surface of the friction body contacts the inner surface of the crown inside the maximum outer diameter of the semicircle on the outer end side of the elongated through hole, so that the stop plug overlaps the window on the side wall of the crown. Since the area is small, that is, the area for supporting the side walls from the inside between the plurality of windows is small, the side walls move toward the center of the crown when the stop plug is inserted into the inner end of the crown. It is difficult to limit the deformation of bending toward the shaft, and it is easy to insert the crown on the shaft. Since the area supported by the shaft is large, the deformation of the side wall toward the center of the crown when the friction body is attached to the outer end of the crown is restricted. It becomes difficult for the body to fall off.

According to the thermochromic writing instrument of the present invention, when a writing object such as a ballpoint pen refill housed in the shaft is brought into contact with the stopper inserted into the inner end of the crown inserted into the shaft. However, the crown does not fall off due to the reaction force due to the writing pressure, and even when the friction body performs friction, the friction body is prevented from falling off together with the crown.

In the present invention, a thermochromic writing instrument in which a crown is attached to the end of a shaft and a friction body is attached to the crown is easy to assemble and has a thermochromic structure in which the crown is difficult to fall off. You get a writing instrument.

1 is a vertical cross-sectional view of a thermochromic ballpoint pen according to this embodiment; FIG. FIG. 2 is an enlarged vertical cross-sectional view of a main part of the writing instrument of FIG. 1; FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 4B is a diagram showing the assembly process of the thermochromic ballpoint pen of the present embodiment, FIG. 4A is a diagram showing the state before assembly, FIG. 4D is a view of the state in which the tail crown is inserted into the barrel, and FIG. 4D is a view of the state in which the friction body is inserted into the tail crown.

Next, the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In this embodiment, a thermochromic ball-point pen in which a ball-point pen refill is accommodated in a barrel will be described, but the present invention is not limited to the following embodiments.
In the description of the drawings, the side where the pen tip is located (front) is referred to as the inside, and the opposite side (rear) is referred to as the outside. Also, in order to make the explanation easier to understand, the same reference numerals are given to the same members and the same parts in the drawings.

FIG. 1 is a longitudinal sectional view of the thermochromic ballpoint pen of this embodiment. FIG. 2 is an enlarged vertical cross-sectional view of a main portion of the writing instrument of FIG. 1; 3 is a cross-sectional view taken along the line AA of FIG. 2. FIG. FIG. 4 is a diagram showing the assembly process of the thermochromic ballpoint pen of this embodiment.

A thermochromic ball-point pen 1 shown in FIG. 1 accommodates a ball-point pen refill 3 inside a barrel 2, and a pen point 3a of the ball-point refill 3 protrudes from a front end opening 2a of the barrel 2. As shown in FIG. The barrel 2 is constructed by screwing a front shaft 21 and a rear shaft 22 together.
A cylindrical tail cap 4 having both ends open is inserted into the rear end opening 2 b of the barrel 2 , and a cylindrical friction ring having both ends opened is attached to the outer end 40 a of a through hole 40 formed in the tail crown 4 . A body 5 is inserted and a stop plug 6 is inserted at the inner end 40b.
The tail crown 4 of this embodiment is molded from ABS resin (acrylonitrile-butadiene-styrene copolymer), the friction body 5 is molded from SEBS resin (styrene-ethylene-butylene-styrene copolymer), and the stopper 6 is Molded from polyethylene resin. The hardness of the friction body 5 is 70 Shore A hardness.

The tail crown 4 includes a small-diameter inserting portion 4 a that is inserted into the rear end opening 2 b of the barrel 2 and a large-diameter brim portion 4 b exposed from the barrel 2 . The friction body 5 includes a small-diameter inserting portion 5a to be inserted into the through hole 40 of the tail crown 4 and a large-diameter collar portion 5b exposed from the tail crown 4 . The stop plug 6 has a small-diameter inserting portion 6 a to be inserted into the through-hole 40 of the tail cap 4 and a large-diameter exposed portion 6 b exposed from the tail cap 4 .
The side wall 41 of the insertion portion 4a of the tail cap 4 is provided with two long hole-shaped windows 41a extending in the direction along the axis at positions facing each other. Further, the side wall 41 is provided with two protrusions 41b at positions facing each other. The two protrusions 41b are engaged with an inner brim-shaped protrusion 2c formed on the inner surface of the rear end opening 2b of the barrel 2, and the tail crown 4 is fixed to the barrel 2. As shown in FIG.
An annular recess 5c is provided in front of the friction body 5, and is fitted with an inner step 4c formed on the inner surface of the through hole 40 of the tail cap 4, so that the friction body 5 is fixed to the tail crown 4. be. Further, the friction body 5 is provided with a through hole 5d.

Next, assembly of the thermochromic ballpoint pen 1 will be described with reference to FIG.
FIG. 4A is a diagram showing a state before assembly. As shown in the figure, the presence of two long hole-shaped windows 41a provided in the side wall 41 allows the side wall 41 to easily bend inward.
FIG. 4B is a diagram showing a state in which the stop plug 6 is inserted into the tail crown 4. The insertion portion 6a is inserted into the tail crown 4, and a part of the outer end of the insertion portion 6a is a window of the tail crown 4. FIG. It is exposed from the portion 41a. Even in this state, the tail cap 4 is open on the outer end 40a side of the through hole 40, and the outer surface of the stop plug 6 is inside the semicircular maximum diameter portion 411a on the inner end side of the long hole-shaped window portion 41a. By contacting the inner surface of the tail crown 4 with the , the area overlapping with the window 41a is small, that is, the area supporting the side wall 41 from the inside between the plurality of windows 41a is small. 41 is less likely to be restricted in its bending deformation toward the center of the tail cap 4, and when the tail crown 4 is inserted into the barrel 2, the protrusion 41b provided on the side wall 41 is aligned with the protrusion of the barrel 2. 2c can be overcome easily.
FIG. 4C is a diagram showing a state in which the tail cap 4 is attached to the barrel 2. FIG. In this state, as described above, the side walls 41 of the tail crown 4 are less likely to be restricted from bending toward the center of the tail crown 4 .
FIG. 4D is a diagram showing a state in which the friction body 5 is inserted into the tail crown 4. The insertion portion 5a is inserted into the tail crown 4, and a part of the inner end of the insertion portion 5a is a window of the tail crown 4. FIG. It is exposed from the portion 41a. In this state, the tail crown 4 is closed at both ends of the through hole 40, and the outer surface of the friction body 5 is positioned inside the maximum diameter portion 412a on the outer end side of the semicircle of the long hole-shaped window portion 41a. By contacting the inner surface of the body 4, the area overlapping with the window 41a is large, that is, the area for supporting the side wall 41 from the inside between the plurality of windows 41a is large. Deformation of the side wall 41 with the friction body 5 inserted is restricted toward the center of the tail crown 4 , and the tail crown 4 is less likely to come off from the shaft body 2 .
Incidentally, as shown in FIG. 2, an inner step 4c formed on the inner surface of the through hole 40 of the tail cap 4 is formed with an inclined surface 4d whose diameter gradually decreases toward the center from the outer end side toward the inner end side. This makes it easier to insert the friction body 5. A sharp corner 4e is provided at the inner end of the inner step 4c, and when it is attached to the tail crown 4, the corner 4e bites into the concave portion 5c of the friction body 5, making it difficult for the friction body 5 to come off.

In the thermochromic ball-point pen 1 of this embodiment, as shown in FIGS. 1 and 2, the ball-point pen refill 3 is elastically pushed backward by the coil spring 7, and the rear end 3b of the ball-point pen refill 3 contacts the stopper 6. However, the tail crown 4 does not fall off from the barrel 2, and even when writing pressure is applied to the pen tip 3a during writing and the ballpoint pen refill 3 is urged rearward, the insertion portion of the friction body 5 remains in place. 5a supports the side wall 41 of the tail crown 4 from the inside, so that the side wall 41 does not bend toward the center of the tail crown 4, and the projection 41b of the tail crown 4 and the inner barrel 2 The state of engagement with the collar 2c is maintained, and the crown 4 is prevented from coming off from the shaft 2.

In the thermochromic ball-point pen 1 of the present embodiment, when the handwriting of the thermochromic ink is rubbed with the friction body 5, even when the friction body 5 is reciprocated while being pressed against the paper surface, as described above. The structure is such that the friction body 5 does not easily fall off from the tail cap 4, and the tail crown 4 does not easily fall off from the barrel 2. - 特許庁

1... thermochromic ballpoint pen,
2... Axle tube, 2a... Front end opening, 2b... Rear end opening, 2c... Protrusion,
21... front shaft, 22... rear shaft,
3... ballpoint pen refill, 3a... pen tip, 3b... rear end,
4... Tail crown 4a... Insertion part 4b... Collar part 4c... Inner step 4d... Inclined surface 4e... Sharp corner part
40... Through hole, 40a... Outer end, 40b... Inner end,
41... side wall, 41a... window, 411a... maximum diameter portion of semicircle, 412a... maximum diameter portion of semicircle,
41b... Protrusion,
5... Friction body 5a... Insertion part 5b... Collar part 5c... Recessed part 5d... Through hole
6... stop plug, 6a... inserting portion, 6b... exposed portion,
7... Coil spring.

Claims (2)

A thermochromic writing instrument capable of thermally discoloring the handwriting by rubbing the handwriting of the thermochromic ink and by the frictional heat generated at that time,
A shaft having an opening at its end, a cylindrical crown inserted into the opening of the shaft, and a friction body inserted into the crown,
A plurality of protrusions are formed on the side wall of the crown body and engage with the protrusions formed on the inner surface of the shaft when the crown body is inserted into the shaft body. A plurality of windows extending in a direction along the axis of the shaft is provided,
A stop plug is attached to the inner end of the crown and a friction body is attached to the outer end of the crown, so that the side wall of the crown bends toward the center of the crown. A thermochromic writing instrument characterized by preventing The window portion has an elongated hole shape, and the outer surface of the stop plug is in contact with the inner surface of the crown body inside the maximum diameter portion of the semicircle on the inner end side of the elongated hole-shaped window portion,
2. The thermochromic writing instrument according to claim 1, wherein the outer surface of said friction body is in contact with the inner surface of said crown member inside the maximum diameter portion of the semicircle on the outer end side of said slot-shaped window.

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