JP2024023142A - Writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a writing instrument capable of suppressing obstruction of attachment and detachment of a tip member from a barrel due to aging deterioration of a grip.

SOLUTION: A writing instrument 1 includes a barrel 10, a tip member 30 coupled to the tip of the barrel 10, and a grip 40 made of a soft elastic body provided on the outer periphery of the barrel 10 and the tip member 30 so as to cover at least the joint between the barrel 10 and the tip member 30. A first gap G1 in the radial direction is formed between the inner peripheral surface of the grip 40 and the outer peripheral surface of the tip member 30.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to writing instruments.

2. Description of the Related Art Writing implements have been known in which a grip made of a soft elastic body is provided on the outer peripheral side of a barrel.
For example, Patent Document 1 describes a writing instrument in which a grip portion formed of a low-temperature thermoplastic resin layer is provided on the outer peripheral side of a pen shaft.

Utility Model Publication No. 6-59089

Incidentally, writing instruments are sometimes designed to have a structure that allows the user to disassemble them.
For example, some writing instruments have a tip member attached to the tip of the barrel that is removable. With this type of writing instrument, the writing instrument can be used again by removing the tip member from the barrel, replacing the ink refill or removing the broken writing lead, and then attaching the tip member to the barrel. It becomes a state.

However, in the case of a writing instrument with a grip as described in Patent Document 1, when the grip becomes sticky due to aging, the frictional force between the outer circumferential surface of the tip member and the inner circumferential surface of the grip increases. However, it is difficult to smoothly attach and detach the tip member from the barrel.
Note that the causes of deterioration of the grip include, for example, melting due to heat, hydrolysis in a high temperature and humid environment, and deterioration due to irradiation with ultraviolet rays.

In view of the above circumstances, it is an object of at least some embodiments of the present invention to provide a writing instrument that can suppress inhibition of attachment and detachment of the tip member from the barrel due to deterioration of the grip over time.

A writing instrument according to at least some embodiments of the present invention includes:
A shaft cylinder,
a tip member coupled to the front end of the barrel;
a grip made of a soft elastic body and provided on the outer peripheral side of the shaft tube and the tip member so as to at least cover a joint portion between the shaft tube and the tip member;
Equipped with
A first gap in the radial direction is formed between the inner peripheral surface of the grip and the outer peripheral surface of the tip member.

According to at least some embodiments of the present invention, since the inner circumferential surface of the grip and the outer circumferential surface of the tip member are not in contact with each other when not writing, the grip becomes sticky due to deterioration over time. However, the influence on the work of attaching and detaching the tip member to and from the shaft cylinder is limited.
Note that during writing, the grip made of a soft elastic body deforms and the gap between the inner circumferential surface of the grip and the outer circumferential surface of the tip member is filled, so this gap has no substantial effect on the writing feeling.

FIG. 1 is a diagram showing the appearance of a writing instrument according to an embodiment. FIG. 2 is a cross-sectional view along the axial direction of the writing instrument shown in FIG. 1. FIG. FIG. 3 is an enlarged view of FIG. 2 showing the front part of the writing instrument. 4 is an enlarged view of the X section in FIG. 3. FIG. 4 is an enlarged view of the Y section in FIG. 3. FIG. FIG. 1 is a perspective view of a chuck set according to an embodiment. FIG. 2 is a cross-sectional view of a part of the chuck set according to one embodiment. FIG. 1 is a partially cross-sectional perspective view of a chuck set according to an embodiment. It is a sectional view showing the tip part of the writing instrument during a knock operation. FIG. 2 is a cross-sectional view showing the tip of the writing instrument that is ready for writing by a knock operation. 11 is a sectional view taken along the line XI-XI in FIG. 10. FIG. 11 is a sectional view taken along line XII-XII in FIG. 10. FIG. FIG. 7 is a cross-sectional view showing the structure around the joint portion between the tip member and the barrel of a writing instrument according to another embodiment. FIG. 7 is a cross-sectional view showing a structure around a connecting portion between a tip member and a barrel of a writing instrument according to yet another embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, and are merely illustrative examples. do not have.

FIG. 1 is a diagram showing the appearance of a writing instrument according to one embodiment. FIG. 2 is a cross-sectional view of the writing instrument shown in FIG. 1 along the axial direction. FIG. 3 is an enlarged view of FIG. 2 showing the front portion of the writing instrument. FIG. 4 is an enlarged view of the X section in FIG. FIG. 5 is an enlarged view of the Y section in FIG.
The writing instrument 1 according to some embodiments of the present invention may be, for example, a mechanical pencil, a ballpoint pen, a marker pen, or the like.
Note that although FIGS. 1 to 5 show a writing instrument 1 as a mechanical pencil, the content described below applies to any type of writing instrument 1, except for mechanisms and structures specific to mechanical pencils.

In some embodiments, as shown in FIGS. 1 and 2, the writing instrument 1 includes a barrel 10, a tip member 30 coupled to the barrel 10, and a grip 40 made of a soft elastic body.
In this specification, for convenience of explanation, the positional relationship of each member in the writing instrument 1 may be expressed as "front" or "front" (or "rear" or "rear") of the writing instrument 1. The "front" or "front" of the writing instrument 1 means the tip member 30 side in the front-rear direction of the writing instrument 1 along the central axis C of the writing instrument 1. On the other hand, the "rear" or "rear" of the writing instrument 1 means the side opposite to the tip member 30 in the front-rear direction of the writing instrument 1 along the central axis C of the writing instrument 1.

The shaft cylinder 10 is a cylindrical member extending along the central axis C of the writing instrument 1.
The cross-sectional shape of the outer shape of the shaft cylinder 10 is not particularly limited, and the cross-sectional shape of at least a part of the outer shape may be circular, polygonal, elliptical, or a combination thereof. In the exemplary embodiment shown in FIG. 1, the portion of the barrel 10 that is not covered by the grip 40 and is exposed to the outside has a polygonal cross-sectional shape from the viewpoint of improving the design of the writing instrument 1.
The barrel 10 has a front end 12 that is coupled to a rear end 32 of a tip member 30, which will be described later. The front end 12 of the barrel 10 and the rear end 32 of the tip member 30 may be connected by any means such as screwing, press fitting, or fitting. In the exemplary embodiment shown in FIG. 2, the front end 12 of the barrel 10 has a male thread that engages with a female thread on the rear end 32 of the tip member 30. In the exemplary embodiment shown in FIG.

In some embodiments, a clip holder 72 with a clip 70 fitted on the outer circumferential side is attached to the rear end portion 13 of the shaft tube 10.
In the exemplary embodiment shown in FIGS. 1 and 2, the rear end 13 of the barrel 10 has an engagement window 15 that engages with the engagement protrusion 73 of the clip holder 72.

The tip member 30 is located at the forefront of the writing instrument 1 and has a rear end 32 that is coupled to the front end 12 of the barrel 10 .
In the exemplary embodiment shown in FIGS. 1 to 3, the tip member 30 is the tip of a mechanical pencil as the writing instrument 1. In the exemplary embodiment shown in FIGS.

The grip 40 is provided on the outer circumferential side of the barrel 10 and the tip member 30 so as to cover at least the joint between the front end 12 of the barrel 10 and the rear end 32 of the tip member 30 . The grip 40 has a cylindrical shape that is approximately concentric with the shaft tube 10 and the tip member 30.

The soft elastic body constituting the grip 40 may be made of elastomer.
Here, "elastomer" in this specification is a general term for polymers having elasticity, and includes, for example, silicone rubber, NBR, synthetic rubber, natural rubber, and the like.

The grip 40 may have a convex portion 42 or unevenness on the outer peripheral surface of the grip 40.
In the exemplary embodiment shown in FIGS. 1-3, the grip 40 has a plurality of protrusions 42 on the outer circumferential surface of the grip 40. In the exemplary embodiment shown in FIGS. Specifically, a protrusion array 43 in which six protrusions 42 are arranged along the front-rear direction (axial direction) of the writing instrument 1 is arranged at a plurality of circumferential positions on the outer peripheral surface of the grip 40.

In some embodiments, the writing instrument 1 includes an outer cylinder 50 provided on the outer peripheral side of the grip 40.
The outer cylinder 50 is made of metal, resin, ceramics, or a composite material thereof. The resin as a constituent material of the outer cylinder 50 may be, for example, a hard resin such as polycarbonate or ABS.

In the exemplary embodiment shown in FIGS. 1-4, the barrel 50 has a plurality of through holes 51. In the exemplary embodiment shown in FIGS.
The plurality of convex portions 42 of the grip 40 described above are provided at positions corresponding to the plurality of through holes 51 of the outer cylinder 50, respectively. The tip of each convex portion 42 projects outward in the radial direction of the outer cylinder 50 through the corresponding through hole 51 . That is, as shown in FIG. 4, the protruding length d of the convex portion 42 from the outer circumferential surface of the outer cylinder 50 is greater than zero (d>0).

In the embodiment shown in FIGS. 1 to 3, the outer cylinder 50 includes a front part 52 into which the tip member 30 is inserted, and a rear part 54 into which the shaft cylinder 10 is inserted. In this embodiment, the outer cylinder 50 is inserted into the tip member 30 and the shaft cylinder 10 with a gap that is small enough to prevent rattling so that the outer cylinder 50 can be easily attached to the tip member 30 and the shaft cylinder 10, but it may be inserted into a slightly tighter fitting state.
Specifically, the front portion 52 of the outer cylinder 50 engages with the first stepped portion 34 provided on the flange portion of the tip member 30. The inner shape of the front portion 52 of the outer cylinder 50 has a shape complementary to the outer shape of a portion of the tip member 30 adjacent to the rear of the first step portion 34 (the rear portion of the first step portion 34). The inner shape of the front part 52 of the outer cylinder 50 and the outer shape of the tip member 30 at the rear part of the first stepped part 34 are not particularly limited as long as they are mutually complementary shapes, and are, for example, circular, oval, or trapezoidal. , polygon, etc.
Similarly, the rear portion 54 of the outer cylinder 50 engages with the second stepped portion 14 provided on the outer peripheral surface of the shaft cylinder 10. The inner shape of the rear portion 54 of the outer cylinder 50 has a shape complementary to the outer shape of a portion of the shaft tube 10 adjacent to the front of the second step portion 14 (the front portion of the second step portion 14). The inner shape of the rear part 54 of the outer cylinder 50 and the outer shape of the shaft cylinder 10 at the front part of the second stepped part 14 are not particularly limited as long as they are mutually complementary shapes, and are, for example, circular, oval, or trapezoidal. , polygon, etc.

In the exemplary embodiment shown in FIGS. 3 and 4, the front portion 52 of the outer cylinder 50 forms a pilot insertion portion with the first stepped portion 34 provided on the flange portion of the tip member 30. The rear end portion 32 of the tip member 30 is inserted into the outer tube 50 in a state where the front portion 52 of the outer tube 50 and the first stepped portion 34 are fitted with a spigot.
Similarly, in the exemplary embodiment shown in FIG. 3, the rear part 54 of the outer cylinder 50 forms a pilot insertion part with the second stepped part 14 provided on the outer peripheral surface of the shaft cylinder 10. The front end 12 of the shaft cylinder 10 is inserted into the outer cylinder 50 in a state where the rear part 54 of the outer cylinder 50 and the second stepped part 14 are fitted with a spigot.

In this way, by inserting the front part 52 and the rear part 54 of the outer cylinder 50 into the tip member 30 and the shaft tube 10, respectively, the joint portion of the tip member 30 and the shaft tube 10 can be reinforced by the outer tube 50. Therefore, the impact when the writing instrument 1 falls can be dispersed to each member.
Further, by fitting the front part 52 and the rear part 54 of the outer cylinder 50 with the tip member 30 and the shaft cylinder 10, respectively, the outer cylinder 50 can be made concentric with the front member 30 and the shaft cylinder 10. 50 is positioned radially. In this case, in the structure described below in which the grip 40 is held by the outer cylinder 50 from the outer circumferential side, the grip 40 can be positioned in the radial direction via the outer cylinder 50, and the center of the grip 40 can be positioned at the tip member 30. And it can be held concentrically with the shaft cylinder 10.

As shown in FIGS. 3 and 4, a first gap G1 in the radial direction is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30. As shown in FIGS. The first gap G1 has a substantially constant size and is formed continuously in the circumferential direction in an annular shape.
When the writing instrument 1 is not in use (not writing), a first gap G1 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30; The surfaces do not touch each other. When the writing instrument 1 is used (during writing), when the grip 40 partially deforms inward in the radial direction due to the pressing force from the user's fingers, the inner circumferential surface of the deformed portion of the grip 40 touches the outer circumferential surface of the tip member 30. Contact.

Note that when the grip 40 has the convex portion 42 and the outer cylinder 50 is provided on the outer peripheral side of the grip 40, as shown in FIG. The protruding length d of the convex portion 42 from the first gap G1 may be set to be larger than the first gap G1 (d>G1).

When the grip 40 has the convex portion 42 and the outer cylinder 50 is provided on the outer peripheral side of the grip 40, the outer cylinder 50 has the above-mentioned structure between the inner peripheral surface of the grip 40 and the outer peripheral surface of the tip member 30. The grip 40 may be held and held from the outer circumferential side so that the first gap G1 is formed.
Specifically, in the outer cylinder 50, a first gap G1 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30, and the center of the grip 40 is approximately aligned with the central axis C of the writing instrument 1. The grip 40 is supported from the outer circumferential side so as to match. In this case, the holding force of the grip 40 by the outer cylinder 50 is at least one of an elastic force that causes the grip 40 to expand outward in the radial direction, and a frictional force caused by the engagement of the convex portion 42 with the through hole 51. May contain.

In the example shown in FIGS. 3 to 5, a third axial gap G3 is formed between the front end of the grip 40 and the tip member 30.
In this case, when the writing instrument 1 is not in use (not writing), both the inner peripheral surface of the grip 40 and the front end surface of the grip 40 are not in contact with the tip member 30.

In some embodiments, as shown in FIGS. 3 and 5, a second radial gap G2 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the shaft tube 10. The second gap G2 has a substantially constant size and is formed continuously in the circumferential direction in an annular shape. In the example shown in FIG. 5, the size of the second gap G2 is set such that the protrusion length d of the convex portion 42 from the outer peripheral surface of the outer cylinder 50 is larger than the second gap G2 (d>G2 ).
When the writing instrument 1 is not in use (not writing), a second gap G2 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the barrel 10; The surfaces do not touch each other.

In some embodiments, the first gap G1 and the second gap G2 are set to different sizes.
In the exemplary embodiment shown in FIG. 5, the first gap G1 is set larger than the second gap G2 in order to avoid contact between the tip member 30 and the grip 40 as much as possible when attaching and detaching the tip member 30 from the shaft cylinder 10. be done.

When the grip 40 has the convex portion 42 and the outer cylinder 50 is provided on the outer peripheral side of the grip 40, the outer cylinder 50 has the above-mentioned structure between the inner peripheral surface of the grip 40 and the outer peripheral surface of the shaft cylinder 10. The grip 40 may be held by being held from the outer circumferential side so that the second gap G2 is formed.
Specifically, in the outer cylinder 50, a second gap G2 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the shaft tube 10, and the center of the grip 40 is approximately aligned with the central axis C of the writing instrument 1. The grip 40 is supported from the outer circumferential side so as to match. In this case, as described above, the holding force of the grip 40 by the outer cylinder 50 is due to the elastic force of the grip 40 that tends to expand radially outward, or the friction caused by the engagement of the convex portion 42 with the through hole 51. It may include at least one of force.

In the example shown in FIGS. 3 and 5, a fourth gap G4 in the axial direction is formed between the rear end of the grip 40 and the shaft tube 10.
In this case, when the writing instrument 1 is not in use (not writing), both the inner circumferential surface of the grip 40 and the rear end surface of the grip 40 are not in contact with the barrel 10 .

When the tip member 30 and the shaft tube 10 are coupled by screwing, as shown in FIGS. 3 and 5, the front part 52 of the outer tube 50 comes into contact with the first step part 34 of the tip member 30, and the outer tube In a state in which the rear portion 54 of the shaft tube 50 is in contact with the second stepped portion 14 of the shaft tube 10, a tightening margin (fifth gap G5) between the tip member 30 and the shaft tube 10 may remain.
That is, as the shaft cylinder 10 is screwed into the tip member 30, the axial clearance between the front part 52 and the rear part 54 of the outer cylinder 50 and the first step part 34 and the second step part 14 increases. Eventually, the front part 52 of the outer cylinder 50 comes into contact with the first stepped part 34, and the rear part 54 of the outer cylinder 50 comes into contact with the second stepped part 14. In this state, the fifth gap G5 in the axial direction remains as a tightening margin between the tip member 30 and the barrel 10, but the outer tube 50 is stretched between the tip member 30 and the barrel 10. Therefore, the shaft cylinder 10 cannot be screwed into the tip member 30 any further.

In this way, the outer cylinder 50 can be reliably fixed to the tip member 30 and the shaft tube 10 while leaving a tightening margin (fifth gap G5), and the outer tube 50 can be securely fixed to the tip member 30 and the shaft tube 10. The reinforcing effect of the tube 50 can be enhanced.
In addition, by regulating the amount of screwing of the shaft tube 10 into the tip member 30 by the outer tube 50, the third gap G3 between the front end of the grip 40 and the tip member 30, and the third gap G3 between the front end of the grip 40 and the shaft tube 10 are A fourth gap G4 between the two can be secured. Therefore, axial compressive force can be prevented from acting on the grip 40, and the risk of plastic deformation of the grip 40 can be reduced.

Next, the internal structure of the writing instrument 1 according to some embodiments will be described with reference to FIGS. 2 to 5.

When the writing instrument 1 is a mechanical pencil, as shown in FIG. 2, the writing instrument 1 according to some embodiments includes a lead tank 80 for accommodating a writing lead, and a relay connected to the front end of the lead tank 80. It includes a member 90 and a chuck set 100 provided on the front side of the relay member 90.

In the exemplary embodiment shown in FIG. 2, the wick tank 80 is a cylindrical member that extends along the central axis C within the shaft tube 10. An eraser 82 is fitted to the rear end of the lead tank 80 to close the storage space for the writing lead. Furthermore, a cap 84 is attached to the rear end of the lead tank 80 so as to cover the eraser 82.
The cap 84 functions as a knock operation section that is a target of a knock operation by the user of the writing instrument 1.

In some embodiments, the writing instrument 1 includes a spring 88 for biasing the lead tank 80 rearward.
In the example shown in FIG. 2, a spring 88 is housed in the shaft cylinder 10 so as to be able to bias a flange 86 provided on the outer periphery of the core tank 80 rearward. The flange 86 of the lead tank 80 is locked by the clip holder 72 when the writing instrument 1 is operated in a non-knocking state, and the lead tank 80 is prevented from slipping out to the rear.

A relay member 90 is connected to the front end of the core tank 80 by any means such as press-fitting, fitting, screwing, or the like.
In the embodiment shown in FIGS. 2, 3, and 5, the rear portion 92 of the relay member 90 is press-fitted into the front opening of the wick tank 80. In addition to a rear part 92 that is press-fitted into the core tank 80, the relay member 90 includes a flange 94 for regulating the amount of press-fitting of the rear part 92 into the core tank 80, and a flange 94 between the rear part 92 and the flange 94. and a front portion 96 located on the opposite side. The front portion 96 of the relay member 90 has a raised portion 97 formed on its outer peripheral surface. Due to the function of this raised portion 97, the front portion 96 can be fitted to a chuck outer cylinder 110 of a chuck set 100, which will be described later. Further, during the knocking operation of the writing instrument 1, the maximum amount of penetration of the front part 96 of the relay member 90 into the chuck outer cylinder 110 is regulated by the contact between the flange 94 of the relay member 90 and the rear end of the chuck outer cylinder 110. may be done.

In some embodiments, the front part 96 of the relay member 90 has a recess 98 for receiving the rear end of the chuck 120 of the chuck set 100 described below, and a recess 98 for pressing the flange 123 of the chuck 120 forward during a knocking operation. and a pressing portion 99 .
The pressing portion 99 is provided so as to protrude in the axial direction along the outer periphery of the front end surface of the front portion 96 of the relay member 90 so as to surround the recess 98 . The depth of the recess 98 (that is, the protruding length of the pressing portion 99) is set to be larger than the length of the portion of the chuck 120 that is rearward of the flange 123.
Note that, as shown in FIGS. 2, 3, and 5, a cavity may be provided inside the raised portion 97 of the relay member 90 in the radial direction to facilitate deformation of the front portion 96 of the relay member 90. In this case, the raised portion 97 can easily overcome the taper 112 of the chuck outer cylinder 110, which will be described later, and a smooth knocking operation can be achieved.

FIG. 6 is a perspective view of the chuck set 100 according to one embodiment. FIG. 7 is a cross-sectional view of a part of the chuck set 100 according to one embodiment. FIG. 8 is a partially cross-sectional perspective view of the chuck set 100 according to one embodiment.

In some embodiments, as shown in FIGS. 2, 3, and 5, the chuck set 100 includes a chuck barrel 110 that is at least partially inserted into the shaft barrel 10, and a chuck barrel 110 that is housed inside the chuck barrel 110. The chuck 120 is movable back and forth relative to the chuck outer cylinder 110 in a closed state.

As shown in FIGS. 5, 7, and 8, the chuck outer cylinder 110 may have a taper 112 on the inner peripheral surface on the rear end side.
The inner diameter of the chuck outer cylinder 110 is constant at D (see FIG. 5) on the rear side of the taper 112. The inner diameter of the chuck outer cylinder 110 decreases toward the front at the taper 112. That is, the inner diameter of the chuck outer cylinder 110 gradually decreases from the diameter D at the rear end of the taper 112 toward the front, and has an inner diameter smaller than D at the front of the taper 112.
With the knocking operation, the front part 96 of the relay member 90 slides toward the back (front) within the inner space of the chuck outer cylinder 110, which is tapered by the taper 112, and the protruding part 97 of the relay member 90 and the chuck outer cylinder slide. The engagement with the rear end of 110 becomes tighter. When the amount of knock operation becomes maximum, the raised portion 97 climbs over the taper 112 and is positioned in front of the taper 112. At this time, the engagement force between the raised portion 97 of the relay member 90 and the rear end portion of the chuck outer cylinder 110 is maximum.
In this way, by forming the taper 112 on the inner circumferential surface on the rear end side of the chuck outer cylinder 110, the protrusion 97 of the relay member 90 and the rear end of the chuck outer cylinder 110 can be adjusted in accordance with the increase or decrease of the amount of knock operation. It is possible to switch the coupling force in stages.

The chuck outer cylinder 110 has a flange 114 on the outer peripheral surface on the front end side. When the writing instrument 1 is operated in a non-knocking manner, the lead tank 80 is urged backward by the spring 88, and as a result, the relay member 90 press-fitted into the lead tank 80 and the chuck outer cylinder 110 that engages with the relay member 90 are also moved to the retracted position. It is in. However, when the writing instrument 1 is operated without knocking, the flange 114 of the chuck outer cylinder 110 comes into contact with the tip of the shaft cylinder 10 and is locked, so that the chuck outer cylinder 110 cannot move back any further. In this way, the maximum retreat distance of the chuck outer cylinder 110 is defined by the engagement of the flange 114 by the tip of the shaft cylinder 10.
Further, the chuck outer cylinder 110 has a front end surface 116 at the frontmost end. The front end surface 116 comes into contact with and is locked against the inner wall of the tip member 30 when the writing instrument 1 is operated by knocking, so that the chuck outer cylinder 110 cannot move forward any further. That is, the maximum forward movement distance of the chuck outer cylinder 110 is defined by the engagement of the front end surface 116 with the inner wall of the tip member 30.

The chuck outer cylinder 110 is hollow inside and can accommodate the chuck 120. In addition to the chuck 120, a spring 118 for biasing the chuck 120 rearward is housed in the cavity within the chuck outer cylinder 110.

The chuck 120 is made of metal, resin, ceramics, or a composite material thereof. The resin used as the constituent material of the chuck 120 may be, for example, a hard resin such as polycarbonate or ABS.
The chuck 120 is not particularly limited as long as it has a configuration that can grip a writing lead, and may have a configuration using a ball chuck mechanism or a collet chuck mechanism, for example. Note that FIGS. 4, 5, 7, and 8 illustrate the chuck 120 of the ball chuck mechanism.

As shown in FIG. 8, the chuck 120 has a half-split structure and includes a first chuck piece 121 and a second chuck piece 122.
The chuck 120 has a variable-size sixth gap G6 between the first chuck piece 121 and the second chuck piece 122, and the chuck 120 can be opened or closed by increasing or decreasing the size of the sixth gap G6. It is possible to switch between states.

FIG. 8 illustrates a chuck 120 having a two-part structure having two chuck pieces 121 and 122. In other embodiments, the chuck 120 has a three-piece structure with three chuck pieces or a four-piece structure with four chuck pieces.

In the embodiments shown in FIGS. 4, 5, 7, and 8, the chuck 120 (each of the first chuck piece 121 and the second chuck piece 122) includes a grip part 124 for gripping a writing lead, and a grip part 124 , and a non-grip portion 128 connected to the grip portion 124 via the step 126 .

In some embodiments, as shown in FIG. 8, the grip 124 has a groove with a width smaller than the diameter of the writing lead. The groove of the grip portion 124 includes a pair of tapered surfaces 125, and each tapered surface 125 has a groove edge (groove edge) 125a. Each groove edge 125a is an edge of the corresponding tapered surface 125, and the groove width is defined by the distance between the pair of groove edges 125a.
In the closed state of the chuck 120, the pair of tapered surfaces 125 of the groove of the first chuck piece 121 and the pair of tapered surfaces 125 of the groove of the second chuck piece 122 touch the writing lead from the outer circumferential side at four circumferential positions. By making contact, the writing lead can be gripped. Note that in this embodiment, the writing lead is held by the pair of tapered surfaces 125 of the grooves of each chuck piece 121, 122, but the writing lead is held by the pair of groove edges 125a of the groove of each chuck piece 121, 122. Good too.

The step 126 is defined by a plane along the radial direction. As shown in FIG. 8, a pair of tapered surfaces 125 forming the grip portion 124 terminate at a step 126. As shown in FIG. Each chuck piece 121, 122 has another groove formed behind the step 126, and this groove has a pair of groove edges 129. Due to the presence of the step 126, the distance between the pair of groove edges 129 is larger than the distance between the pair of groove edges 125a forming the grip portion 124. In this way, in the non-gripping part 128 located on the opposite side of the gripping part 124 with the step 126 in between, the pair of groove edges 129 are each radially more disposed than the pair of groove edges 125a constituting the gripping part 124. They are retreating to the outside. Therefore, the non-grip portion 128 including the pair of groove edges 129 is configured not to contact the writing lead gripped by the grip portion 124 (the pair of tapered surfaces 125) when the chuck 120 is in the closed state.

In some embodiments, the non-grip portion 128 has a protrusion 130 for guiding the writing lead to the grip portion 124. As shown in FIGS. 4 and 8, the protrusion amount of the convex portion 130 gradually increases toward the front until reaching the ridge line 131, and cuts down in front of the ridge line 131 to reach the inner circumferential surface of the non-grip portion 128. Connected. That is, the protrusion amount of the convex portion 130 in the radial direction becomes maximum at the ridge line 131.

The protrusions 130 may be provided continuously in the circumferential direction of each chuck piece 121, 122, or a plurality of protrusions 130 may be provided discretely in the circumferential direction for each chuck piece 121, 122. good.
In the exemplary embodiment, two protrusions 130 are provided for each chuck piece 121, 122 at an angle of 80 degrees to 120 degrees (for example, about 107 degrees) (FIG. 8 shows a second chuck (showing two protrusions 130 on piece 122).
In this case, a total of four protrusions 130 are arranged around the central axis C, but they may be arranged at equal intervals, or five or six, but it is preferable to arrange an even number. preferable.

Although the specific shape of the convex portion 130 is not particularly limited, it is desirable that the portion rearward of the ridge line 131 has a convex curved shape that allows the writing lead to be smoothly guided to the grip portion 124 .
For example, the rear portion of the convex portion 130 from the ridgeline 131 may have a hemispherical shape, a teardrop shape, or a three-dimensional curved shape similar thereto.

In the embodiments shown in FIGS. 4, 5, 7, and 8, a plurality of convex portions 130 are provided on the inner surface of the groove having a pair of groove edges 129 of the non-gripping portion 128 so as to protrude radially inward. The protrusion amount of each convex portion 130 is determined based on the radial position of the pair of groove edges 125a of the grip portion 124 when the chuck 120 is in the closed state. It is set under the condition that it is located outside. Therefore, even when the chuck 120 is in the closed state, the ridge line 131 of the convex portion 130 is located radially outward from the outer circumferential surface of the writing core, and the convex portion 130 does not come into contact with the writing core.

In the embodiments shown in FIGS. 4, 5, 7, and 8, the chuck 120 is provided with a recess 132 on the outer peripheral surface of the front end. A ball 134 fits into the recess 132 . The ball 134 is held between the chuck 120 and a chuck ring 136 that covers the front end of the chuck 120. The chuck ring 136 is fixed to the chuck outer cylinder 110 and has a tapered portion 137 whose diameter increases toward the front. The ball 134 contacts the tapered portion 137 of the chuck ring 136 on the outside in the radial direction, and contacts the concave surface of the recess 132 on the inside in the radial direction.
In the closed state of the chuck 120, the chuck 120 is urged backward by the spring 118, and due to the wedge effect of the tapered portion 137, each chuck piece 121, 122 receives a radially inward pressing force from the ball 134, and the chuck 120 is Closed. On the other hand, when the chuck 120 moves forward relative to the chuck ring 136 fixed to the chuck outer cylinder 110 via the relay member 90, the balls 134 roll forward on the tapered portion 137, and the pair of chuck pieces The sixth gap G6 (see FIG. 8) between 121 and 122 widens, and the chuck 120 shifts to the open state.
A chuck stopper 138 fits into the front opening of the chuck ring 136 . A recess is provided on the rear end side of the chuck stopper 138 so as not to inhibit the relative back and forth movement of the chuck 120 with respect to the chuck ring 136 and the chuck stopper 138. When the chuck 120 moves forward relative to the chuck ring 136 and the chuck outer cylinder 110, the front end of the chuck 120 enters a recess provided in the chuck stopper 138.

In some embodiments, the writing instrument 1 includes a slider 140 provided within the tip member 30 so as to be located in front of the chuck set 100, as shown in FIGS. 2 to 4.
An annular fixing ring 150 fixed to the tip member 30 is provided on the outer peripheral side of the slider 140. The slider 140 is inserted into a through hole of an annular fixing ring 150 and is configured to be movable back and forth relative to the fixing ring 150 fixed to the tip member 30 .

The slider 140 has a taper 142 (see FIG. 4) on its outer circumferential surface where the slider 140 decreases in diameter toward the rear. The slider 140 has a large diameter portion on the front side and a small diameter portion on the rear side with the taper 142 in between.
When the writing instrument 1 is not knocked, the large diameter portion on the front side of the taper 142 of the slider 140 is in a state of being engaged with the fixing ring 150, and the fixing ring 150 is loosely fixed to the slider 140 by frictional force.

The slider 140 is urged forward by a spring 152 (see FIG. 4) provided between the fixed ring 150 and the slider 140.
The biasing force of the spring 152 is set to be smaller than the frictional force at the engagement portion between the large diameter portion of the slider 140 and the fixed ring 150. Therefore, even when the writing instrument 1 is not knocked, even if the biasing force of the spring 152 acts, the large diameter portion of the slider 140 and the fixing ring 150 are not disengaged from each other.
On the other hand, when the slider 140 is pressed forward as the chuck set 100 advances during the knock operation of the writing instrument 1, the large diameter portion of the slider 140 and the fixing ring 150 are disengaged, and the slider 140 is moved by the spring 152. Moves forward due to biasing force.

A core pipe 144 is press-fitted into the slider 140 from the front, and a core detent member 146 is press-fitted from the rear. The core pipe 144 and the core detent member 146 are fixed to the slider 140 and move together with the slider 140 when the slider 140 moves in the front-rear direction.
The lead pipe 144 protrudes from the tip member 30 to protect the writing lead when the writing instrument 1 is used. The lead detent member 146 holds the writing lead with elastic force and prevents the writing lead from returning backward when the writing lead is fed out by multiple knocking operations.

In the embodiment described above, the writing instrument 1 includes three types of springs 88, 118, and 152.
The loads of these three types of springs 88, 118, and 152 are set to increase in the order of spring 118, spring 152, and spring 88.

Next, with reference to FIGS. 3 to 4 and FIGS. 9 to 12, the movements of each member associated with the knocking operation of the writing instrument 1 will be described.
FIG. 9 is a sectional view showing the tip of the writing instrument 1 during a knocking operation. FIG. 10 is a cross-sectional view showing the tip of the writing instrument 1 that is ready for writing by a knocking operation. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 10.

As shown in FIGS. 3 and 4, when the writing instrument 1 is not used for writing, the chuck outer cylinder 110 is not pressed by the relay member 90, and the chuck outer cylinder 110 retreats to a position where the flange 114 contacts the shaft cylinder 10. ing. At this time, the chuck 120 surrounded by the chuck outer cylinder 110 is also not pressed by the relay member 90. Therefore, the chuck 120 is urged rearward by the urging force of the spring 118, and is retreated rearward relative to the chuck outer cylinder 110. Therefore, the first chuck piece 121 and the second chuck piece 122 are pressed toward each other by the ball 134 due to the wedge effect of the tapered portion 137 of the chuck ring 136, and the chuck 120 is in the closed state. Therefore, even if the writing lead from the lead tank 80 enters the inside of the chuck 120, it will stop before the gripping part 124 of the chuck 120.

On the other hand, in the writing instrument 1 during the knocking operation, the lead tank 80 and the relay member 90 move forward due to the knocking operation. At this time, since the raised portion 97 of the relay member 90 is engaged with a portion of the inner circumferential surface of the chuck outer cylinder 110 that is rearward of the taper 112, the chuck outer cylinder 110 also moves forward together with the relay member 90. As shown in FIG. 9, when the chuck outer cylinder 110 advances to a position where the front end surface 116 abuts the wall surface of the tip member 30, the chuck outer cylinder 110 stops because it cannot advance any further.
Further, as the chuck outer cylinder 110 moves forward, the chuck stopper 138 attached to the chuck ring 136 press-fitted into the chuck outer cylinder 110 moves forward. As a result, the slider 140 is pushed forward via the chuck stopper 138, and the large diameter portion of the slider 140 and the fixing ring 150 are disengaged from each other. As a result, the slider 140 moves forward by the biasing force of the spring 152, and the core pipe 144 protrudes from the tip member 30.

When the amount of knocking operation increases further after the chuck outer cylinder 110 stops (when the knocking becomes deeper), the pressing part 99 (see FIGS. 5, 7, and 8) of the front part 96 of the relay member 90 presses against the flange of the chuck 120. 123 (see FIGS. 5, 7, and 8), and the chuck 120 begins to move forward relative to the chuck outer cylinder 110.
As the pressing portion 99 (see FIGS. 5, 7, and 8) of the relay member 90 moves, the chuck 120 moves relative to the chuck outer cylinder 110.
Here, the inner diameter of the chuck outer cylinder 110 becomes narrower toward the front at the taper 112. Therefore, when the raised portion 97 of the relay member 90 moves forward over the taper 112, the engagement between the chuck outer cylinder 110 and the relay member 90 becomes tight.

At this time, the chuck ring 136 surrounding the chuck 120 and the ball 134 is press-fitted into the chuck outer cylinder 110, which is locked by the wall surface of the tip member 30, and remains immovable.
As a result of the forward relative movement of the chuck 120 with respect to the chuck ring 136, the contact position of the ball 134 with respect to the chuck ring 136 is shifted to the front portion of the tapered portion 137 of the chuck ring 136 where the inner diameter is larger, and the chuck 120 opens. When the chuck 120 opens and the sixth gap G6 between the first chuck piece 121 and the second chuck piece 122 in the grip part 124 of the chuck 120 becomes larger, the writing lead can pass through the grip part 124. Therefore, the writing lead that has passed through the grip portion 124 of the chuck 120 falls due to its own weight and stops before the lead detent member 146 provided on the slider 140.

Thereafter, when the user of the writing instrument 1 releases his or her finger from the cap 84 (knocking operation part) to complete the knocking operation, the lead tank 80 and the relay member 90 begin to move rearward due to the biasing force of the spring 88.
At this time, as described above, since the raised portion 97 of the relay member 90 is tightly engaged with the inner peripheral surface of the chuck outer cylinder 110 at a position forward of the taper 112, the chuck outer cylinder 110 also retreats together with the relay member 90. do. The retraction of the chuck outer cylinder 110 stops at the position where the flange 114 of the chuck outer cylinder 110 contacts the front end 12 of the shaft cylinder 10, and the chuck outer cylinder 110 cannot move back any further. After that, the relay member 90 continues to retreat toward the original position before the knocking operation, the protrusion 97 of the relay member 90 descends down the taper 112, and the engagement between the relay member 90 and the chuck outer cylinder 110 becomes loose.

Further, when the relay member 90 and the chuck outer cylinder 110 start to move backward with the completion of the knocking operation, the chuck 120 also starts to move backward due to the urging force of the spring 118. Here, the chuck 120 is in an open state, and the writing lead is not restrained by the grip part 124 of the chuck 120, and the writing lead remains immobile, falling in front of the lead detent member 146 due to its own weight.
When the retraction of the chuck outer cylinder 110 stops, the chuck 120 starts to move rearward relative to the chuck outer cylinder 110 due to the urging force of the spring 118. At this time, the ball 134 rolls backward on the tapered portion 137 of the chuck ring 136, and the chuck 120 is closed due to the wedge effect (the sixth gap G6 is reduced). Since the writing lead is inserted into the gripping part 124 of the chuck 120, the sixth gap G6 between the chuck pieces 121 and 122 continues to decrease until the writing lead is gripped by the gripping part 124. When the writing lead is gripped by the gripping portion 124 of the chuck 120, the sixth gap G6 between the chuck pieces 121 and 122 stops decreasing, and the retraction of the chuck 120 ends.

After this, when the knocking operation is performed again, the core tank 80, the relay member 90, the chuck outer cylinder 110, and the chuck 120 move forward based on the same principle as described above. As a result, the writing lead held by the chuck 120 moves forward as the chuck 120 moves forward, and is press-fitted into the lead detent member 146.
By further repeating the knocking operation, the writing lead is fed forward, reaching the tip of the lead pipe 144, and becomes ready for writing. FIG. 9 shows a state in which the writing instrument 1 is in a knocking operation just before it becomes ready for writing. In this state, when the knocking operation is completed, the lead tank 80, the relay member 90, the chuck outer cylinder 110, and the chuck 120 retreat, and the writing lead is gripped by the chuck 120, resulting in the state shown in FIG. 10.

Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and may include other embodiments as long as they do not go against the spirit of the present invention.

FIG. 13 is a cross-sectional view showing the structure around the joint portion between the tip member 30 and the shaft tube 10 of a writing instrument according to another embodiment. FIG. 14 is a cross-sectional view showing the structure around the joint portion between the tip member 30 and the shaft tube 10 of a writing instrument according to yet another embodiment.
In addition, in FIGS. 13 and 14, the same elements as those of the writing instrument 1 according to the above-described embodiment are given the same reference numerals for the purpose of omitting duplicate explanation.

In the exemplary embodiment shown in FIG. 13, no gap is formed between the inner peripheral surface of the grip 40 and the inner peripheral surface of the barrel 10, and the grip 40 is sandwiched between the outer barrel 50 and the barrel 10. It is set up so that
In this case, the first gap G1 is formed on the inner periphery side at the front part of the grip 40, while there is no gap on the inner periphery side at the rear part of the grip 40. There can be a significant difference in the fit of the writing instrument 1 depending on how it is held. Furthermore, since the first gap G1 is provided between the grip 40 and the tip member 30, even if the grip 40 becomes sticky, it will not affect the work of attaching and detaching the tip member 30 to and from the shaft tube 10. Impact is limited.
The writing instrument according to the embodiment shown in FIG. 13 has the same configuration as the writing instrument 1 shown in FIGS. 1 to 5, except that it does not have the second gap G2.

In the exemplary embodiment shown in FIG. 14, the front end of the grip 40 is in contact with the tip member 30, and no third gap G3 is formed between the front end of the grip 40 and the tip member 30. Although not shown in FIG. 14, the rear end of the grip 40 is in contact with the shaft tube 10, and a fourth gap G4 in the axial direction is not formed between the rear end of the grip 40 and the shaft tube 10. .
The through hole 51 of the outer cylinder 50 is sufficiently large with respect to the convex part 42 of the grip 40, and the position of the grip 40 in the front-rear direction with respect to the outer cylinder 50 cannot be defined by the engagement of the convex part 42 with the through hole 51. Even in this case, the grip 40 can be positioned by bringing the front end and rear end of the grip 40 into contact with the tip member 30 and the barrel 10, respectively.
Note that the writing instrument according to the embodiment described above with reference to FIG. 14 has the same configuration as the writing instrument 1 shown in FIGS. 1 to 5, except that it does not have the third gap G3 and the fourth gap G4. .

Hereinafter, the structure and operation of the writing instrument 1 in some embodiments will be described.

[1] Writing instrument 1 according to some embodiments includes:
A shaft cylinder 10,
a tip member 30 coupled to the tip of the shaft cylinder 10;
a grip 40 made of a soft elastic body and provided on the outer peripheral sides of the barrel 10 and the tip member 30 so as to at least cover the joint between the barrel 10 and the tip member 30;
Equipped with
A first gap G1 in the radial direction is formed between the inner peripheral surface of the grip 40 and the outer peripheral surface of the tip member 30.

According to the configuration [1] above, since the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30 are not in contact with each other when not writing, the grip 40 does not become sticky due to aging deterioration or the like. However, the influence on the work of attaching and detaching the tip member 30 to and from the shaft tube 10 is limited. Note that during writing, the grip 40 deforms and the first gap G1 between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30 is filled, so that the substantial influence of the first gap G1 on the writing feeling is do not have.

[2] In some embodiments, in the configuration of [1] above,
The grip 40 has a convex portion 42 or unevenness on the outer peripheral surface of the grip 40.

According to the configuration [2] above, by forming the convex portion 42 or the unevenness on the outer circumferential surface of the grip 40, the fit is improved and a good writing feeling can be obtained. Further, since the convex portion 42 or the concave and convex portions provided as part of the grip 40 made of a soft elastic body have flexibility, the burden on the fingers during writing can be reduced.

[3] In some embodiments, in the configuration of [1] or [2] above, the writing instrument 1 includes:
It has a plurality of through holes 51 and an outer cylinder 50 provided on the outer peripheral side of the grip 40,
The grip 40 has a plurality of protrusions 42 provided on the outer peripheral surface of the grip 40 at positions corresponding to the plurality of through holes 51 of the outer cylinder 50,
The tip of each convex portion 42 projects radially outward of the outer cylinder 50 through the through hole 51 .

According to the configuration [3] above, by making the convex portion 42 of the flexible grip 40 protrude from the through hole 51 of the outer tube 50, the convex portion 42 can be reliably gripped while the outer tube 50 is being gripped during writing. Provides a good fit.

[4] In some embodiments, in the configuration of [3] above,
The protrusion length of the convex portion 42 from the outer circumferential surface of the outer cylinder 50 is larger than the first gap G1.

According to the configuration [4] above, even if the grip 40 is deformed by the pressing force from the fingers during writing, the tip member 30 supports the grip 40 from the inside in the radial direction, so that the convexity inward of the through hole 51 is prevented. It is possible to suppress the part 42 from being immersed. Therefore, when writing, it is possible to maintain the state in which the convex portion 42 slightly protrudes from the outer peripheral surface of the outer cylinder 50, and an excellent fit can be obtained.

[5] In some embodiments, in the configuration of [3] above,
The outer cylinder 50 holds and holds the grip 40 from the outer circumferential side so that a first gap G1 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30.

According to the configuration [5] above, the grip 40 is supported by the outer cylinder 50 so that the first gap G1 is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30. During writing, the inner circumferential surface of the grip 40 and the outer circumferential surface of the tip member 30 can maintain a non-contact state. Therefore, even if the grip 40 becomes sticky due to aged deterioration or the like, the operation of attaching and detaching the tip member 30 to and from the shaft tube 10 can be performed smoothly.

[6] In some embodiments, in the configuration of [5] above,
The outer tube 50 holds and holds the grip 40 from the outer circumferential side so that a second gap G2 in the radial direction is formed between the inner circumferential surface of the grip 40 and the outer circumferential surface of the shaft tube 10.

According to the configuration [6] above, since the inner circumferential surface of the grip 40 and the outer circumferential surface of the shaft tube 10 are not in contact with each other when not writing, the grip 40 does not become sticky due to deterioration over time or the like. Even if the outer tube 50 and the grip 40 are attached to and detached from the shaft tube 10, it is difficult to obstruct the operation of attaching and detaching the outer tube 50 and the grip 40 to and from the shaft tube 10.

[7] In some embodiments, in the configuration of [6] above,
The second gap G2 is set to a different size from the first gap G1.

According to the configuration [7] above, since the size of the gap (the first gap G1 and the second gap G2) formed on the inner peripheral side of the grip 40 differs depending on the location, the grip of the grip 40 and the outer cylinder 50 is By changing the position, it is possible to obtain a feeling of fit according to the user's preference of the writing instrument 1.

[8] In some embodiments, in any of the configurations of [3] to [7] above,
The tip member 30 is inserted into the front part 52 of the outer cylinder 50, and the shaft cylinder 10 is inserted into the rear part 54 of the outer cylinder 50.

According to the configuration [8] above, by inserting both ends of the outer cylinder 50 into the tip member 30 and the shaft tube 10, respectively, the joint portion of the tip member 30 and the shaft tube 10 can be reinforced by the outer tube 50. This allows the impact when the writing instrument 1 falls to be dispersed to each member.

[9] In some embodiments, in the configuration of [8] above,
The outer cylinder 50 is
a front portion 52 that comes into contact with the first stepped portion 34 of the tip member 30;
a rear portion 54 that comes into contact with the second stepped portion 14 of the shaft tube 10;
has
The tip member 30 is screwed onto the shaft tube 10,
When the front part 52 and the rear part 54 of the outer cylinder 50 are in contact with the first step part 34 and the second step part 14, respectively, a tightening margin (fifth gap G5) of the tip member 30 with respect to the shaft cylinder 10 remains. There is.

According to the configuration [9] above, by leaving a tightening margin (fifth gap G5) between the tip member 30 and the barrel 10, the outer tube 50 can be securely fixed to the tip member 30 and the barrel 10. This makes it possible to enhance the reinforcing effect of the outer cylinder 50 at the joint portion of the tip member 30 and the shaft cylinder 10.

[10] In some embodiments, in any of the configurations of [1] to [9] above, the writing instrument 1 includes:
a chuck outer cylinder 110 that is at least partially inserted into the shaft cylinder 10;
a chuck 120 that is housed inside the chuck outer cylinder 110 and is provided so as to be movable back and forth relative to the chuck outer cylinder 110;
The chuck 120 is
a grip part 124 that comes into contact with and grips the writing lead when the chuck 120 is in the closed state;
a step 126 provided at the rear end of the grip portion 124 and defined by a surface along the radial direction;
a non-grip portion 128 connected to the grip portion 124 via a step 126;
has
The non-grip portion 128 has a convex portion 130 for guiding the writing lead to the grip portion 124.

According to the configuration [10] above, by providing the step 126 defined by the surface along the radial direction at the rear end of the gripping portion 124, the certainty of gripping the writing lead by the gripping portion 124 is increased due to the edge effect. . Therefore, even if abrasion powder of the writing lead accumulates in the gripping part 124 as the writing implement 1 is used, the writing lead can be reliably gripped by the gripping part 124. In addition, the step 126 defined by the surface along the radial direction can capture abrasion powder of the writing lead that tries to enter the gripping part 124 from the non-gripping part 128 side, and prevents the writing lead from entering the gripping part 124. Accumulation of wear particles can be suppressed.
On the other hand, a disadvantage of providing the step 126 defined by the surface along the radial direction at the rear end of the grip part 124 is that when the writing lead falls smoothly under its own weight to the front of the lead detent member 146 during a knock operation, the writing There is a risk that the core may get caught on the step 126. In this regard, according to the configuration [10] above, since the convex part 130 for guiding the writing lead to the gripping part 124 is provided on the non-gripping part 128, it is possible to prevent the writing lead from getting caught on the step 126 and to write. The core can be smoothly guided to the grip portion 124 side.

Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and changes may be made to the above-described embodiments without departing from the spirit of the present invention. Good too.

For example, in some of the embodiments described above, no particular surface treatment is performed on the ball 134, the members in contact with the ball 134, and the chuck set 100 (chuck outer cylinder 110 and chuck 120), but in some other embodiments, A lubricating film may be formed on at least a portion of the surface of the ball 134, the member in contact with the ball 134, and the chuck set 100. The lubricating film can be formed, for example, by applying a lubricant containing stearic acid to the surface of the ball 134, a member in contact with the ball 134, or the chuck set 100.
The range to which the lubricating film is applied can be arbitrarily set according to the specifications of the writing instrument 1. The lubricating coating can be applied to, for example, the ball 134, the chuck 120 in contact with the ball 134, the chuck ring 136 in contact with the ball 134, the chuck set 100 including the chuck 120 and the chuck outer cylinder 110, or a combination of two or more of these. can be mentioned.

In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric", or "coaxial" are used. shall not only strictly represent such an arrangement, but also represent a state in which they are relatively displaced with a tolerance or an angle or distance that allows the same function to be obtained.
For example, expressions such as "same,""equal," and "homogeneous" that indicate that things are in an equal state do not only mean that things are exactly equal, but also have tolerances or differences in the degree to which the same function can be obtained. It also represents the existing state.
In addition, in this specification, expressions expressing shapes such as a square shape or a cylindrical shape do not only mean shapes such as a square shape or a cylindrical shape in a strict geometric sense, but also within the range where the same effect can be obtained. , shall also represent shapes including uneven parts, chamfered parts, etc.
Furthermore, in this specification, the expressions "comprising,""including," or "having" one component are not exclusive expressions that exclude the presence of other components.

1 : Writing instrument 10 : Barrel 12 : Front end 13 : Rear end 14 : Second step part 30 : Tip member 32 : Rear end part 34 : First step part 40 : Grip 42 : Convex part 50 : Outer cylinder 51 : Through hole 52 : Front part 54 : Rear part 80 : Core tank 88 : Spring 90 : Relay member 92 : Rear part 94 : Flange 96 : Front part 97 : Protruding part 98 : Recessed part 99 : Pressing part 100 : Chuck set 110 : Chuck Outer cylinder 112 : Taper 114 : Flange 116 : Front end surface 118 : Spring 120 : Chuck 121 : First chuck piece 121 : Chuck piece 122 : Second chuck piece 122 : Chuck piece 123 : Flange 124 : Grip part 126 : Step 128 : Non-grip portion 130: Convex portion 140: Slider 144: Core pipe 146: Core detent member 150: Fixed ring 152: Spring G1: First gap G2: Second gap

Claims (10)

A shaft cylinder,
a tip member coupled to the front end of the barrel;
a grip made of a soft elastic body and provided on the outer peripheral side of the shaft tube and the tip member so as to at least cover a joint portion between the shaft tube and the tip member;
Equipped with
A writing instrument in which a first radial gap is formed between an inner circumferential surface of the grip and an outer circumferential surface of the tip member. The writing instrument according to claim 1, wherein the grip has a convex portion or an uneven surface on an outer peripheral surface of the grip. An outer cylinder having a plurality of through holes and provided on the outer peripheral side of the grip,
The grip has a plurality of protrusions provided on the outer peripheral surface of the grip at positions corresponding to the plurality of through holes of the outer cylinder,
The writing instrument according to claim 1 or 2, wherein a tip of each of the convex portions projects radially outward of the outer cylinder through the through hole. The writing instrument according to claim 3, wherein a protruding length of the convex portion from the outer circumferential surface of the outer cylinder is greater than the first gap. The writing instrument according to claim 3, wherein the outer cylinder holds and holds the grip from the outer circumferential side so that the first gap is formed between the inner circumferential surface of the grip and the outer circumferential surface of the tip member. . 6. The outer cylinder holds and holds the grip from the outer peripheral side so that a second gap in the radial direction is formed between the inner peripheral surface of the grip and the outer peripheral surface of the shaft cylinder. writing utensils. The writing instrument according to claim 6, wherein the second gap is set to a different size from the first gap. The writing instrument according to claim 3, wherein the tip member is inserted into the front part of the outer cylinder, and the shaft cylinder is inserted into the rear part of the outer cylinder. The outer cylinder is
the front portion that comes into contact with the first step portion of the tip member;
the rear portion that comes into contact with the second stepped portion of the shaft cylinder;
has
The tip member is screwed onto the barrel,
According to claim 8, in a state where the front part and the rear part of the outer cylinder are in contact with the first step part and the second step part, respectively, there remains an interference of the tip member with respect to the shaft cylinder. writing utensils. a chuck outer cylinder that is at least partially inserted into the shaft cylinder;
a chuck that is housed inside the chuck outer cylinder and is provided so as to be relatively movable back and forth with respect to the chuck outer cylinder,
The chuck is
a gripping portion that comes into contact with the writing lead and grips the writing lead when the chuck is in a closed state;
a step provided at the rear end of the grip portion and defined by a surface along the radial direction;
a non-gripping part connected to the gripping part via the step;
has
The writing instrument according to claim 1 or 2, wherein the non-grip portion has a convex portion for guiding the writing lead to the grip portion.

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