JP7667673B2 - Knock-type writing instrument - Google Patents

Description

The present invention relates to a knock-type writing instrument.

There are known so-called knock-type writing instruments that have an operating part equipped with a knock member at the rear end of the barrel, and that switch between a writing state in which the writing part (the pen tip) protrudes from the tip of the barrel and a non-writing state in which the writing part is retracted into the barrel by performing a knock operation that presses the operating part forward against the biasing force of a spring arranged inside the barrel (see, for example, Patent Document 1). In a knock-type writing instrument, the knock operation causes the knock member (corresponding to the cam member in Patent Document 1) to move forward together with the rotor, causing the rotor to rotate. The knock-type writing instrument switches between a writing state and a non-writing state in response to the rotation of the rotor accompanying the knock operation.

Patent document 1 discloses a structure for preventing rotation of a knock member about its central axis for a fitting member (corresponding to the knock member in patent document 1) that fits into the knock member and has a clip.

International Publication No. 2017/104468

In general, it is desirable for parts assembled by fitting or the like for the purpose of fixing to not move relative to one another due to external forces, i.e., not to come loose or become displaced. With reference to Figures 5 to 7, problems caused by the relative movement of the knock member and the fitting member will be explained.

Figure 5 is a cross-sectional view of a conventional knock-type writing instrument 100 corresponding to Figure 2 described later. The knock-type writing instrument 100 has a knock mechanism 110. The knock mechanism 110 has an outer cam 120, a cylindrical knock member 130, a rotor 140, and a fitting member 150 equipped with a connection portion 151 for connecting a clip.

Figure 6 is a schematic diagram showing the relationship between the knock member 130, the engaging member 150, and the restricting portion 160 in a conventional knock-type writing instrument 100. The restricting portion 160 is configured as a side surface of the notch portion 108 that is cut forward from the rear end surface of the rear barrel 103. Figure 6 (A) shows the knock-type writing instrument 100 in a non-writing state, and Figure 6 (B) shows the knock-type writing instrument 100 in a state during a knock operation. The connecting portion 151 is configured to move in the front-rear direction within the notch portion 108 by the knock operation. Figure 7 is another schematic diagram showing the relationship between the knock member 130, the engaging member 150, and the restricting portion 160 in a conventional knock-type writing instrument 100.

Figures 6 and 7 are schematic diagrams showing the positional relationship of the knock mechanism 110, and show the positions of the locking protrusion 131 of the knock member 130 and the inner cam 141 of the rotor 140, which will be described later, relative to a partial circumferential development of the outer cam 120 and the regulating portion 160. In the figures, the lower side is the front of the knock type writing instrument 100, and the upper side is the rear of the knock type writing instrument 100.

In detail, outer cams 120, which are cam protrusions constituting part of the knock mechanism 110, are provided at equal intervals along the circumferential direction in front of the restricting portion 160 of the rear axle 103. Adjacent outer cams 120 define guide grooves 121 extending in the front-rear direction. Locking protrusions 131 are provided at equal intervals along the circumferential direction on the outer peripheral surface of the front side of the knock member 130. Each of the locking protrusions 131 is disposed within the guide groove 121 between adjacent outer cams 120. Each of the locking protrusions 131 is configured to move in the front-rear direction within the guide groove 121 by the knock operation. A cam surface 132 is formed on the front end surface of the knock member 130.

The fitting member 150 is fitted to the outer peripheral surface of the rear end of the knock member 130. The inner cams 141, which are protrusions extending in the front-rear direction, are provided on the outer peripheral surface of the rotor 140 at equal intervals in the circumferential direction. For convenience, the inner cams 141 are hatched in the figure, but do not represent a cross section. In the knock-type writing instrument 100 in the non-writing state as shown in FIG. 6(A), each of the inner cams 141 is disposed in the guide groove 121 of the outer cam 120. The rotor 140 has a cam receiving surface 142 that cooperates with the cam surface 132 of the knock member 130 and has a complementary shape. The rotor 140 is given a rotational force by the cooperation of the cam surface 132 of the knock member 130 and the cam receiving surface 142 of the rotor 140, and rotates around the central axis. The rotor 140 also cooperates with the outer cam 120 to help switch between the writing state and the non-writing state. The regulating portion 160 is composed of two side surfaces that are inclined toward each other toward the front in FIG. 6, which shows the circumferentially expanded view.

Referring to FIG. 6A, the rotor 140 is biased backward, so that the cam surface 132 of the knock member 130 and the cam receiving surface 142 of the rotor 140 cooperate with each other to rotate the knock member 130 to the right and the rotor 140 to the left in the figure. The rotation of the knock member 130 is restricted by the engagement protrusion 131 abutting against the side of one of the outer cams 120, and the rotation of the rotor 140 is restricted by the engagement of the inner cam 141 abutting against the side of the other outer cam 120. At this time, the engagement protrusion 131 and the other outer cam 120 are separated by a distance d1 along the circumferential direction. Also, the connection portion 151 and the restriction portion 160 are separated by a minimum distance d2 along the circumferential direction. The distance d1 is set to be smaller than the distance d2.

In FIG. 6(A), the center line c1 of the cutout portion 108 and the center line c2 of the connection portion 151 are aligned. When a knock operation is performed in this state, the center lines c1 and c2 remain substantially aligned (FIG. 6(B)).

6(A), when the fitting member 150 is grasped and rotated against the biasing force that rotates the knock member 130, i.e., to the left in the figure, the knock member 130 and the fitting member 150 rotate together around the central axis of the knock member 130. The rotation of the knock member 130 and the fitting member 150 is restricted by the engagement protrusion 131 of the knock member 130 abutting against the side of the other outer cam 120 (FIG. 7(A)). At this time, the amount of rotation of the knock member 130 and the fitting member 150, i.e., the rotation angle, is the distance d1 mentioned above when expressed as the distance from the center line c1 in FIG. 7.

When further force is applied to the fitting member 150 from the state shown in FIG. 7(A) and the fitting member 150 is rotated around the central axis of the knock member 130 relative to the knock member 130, only the fitting member 150 rotates. The rotation of the fitting member 150 is restricted by the connection portion 151 abutting against the restricting portion 160 (FIG. 7(B)). At this time, the rotation angle of the fitting member 150, expressed as the distance from the center line c1 in FIG. 7, is the above-mentioned distance d2.

When the applied force is released from the state shown in Figure 7 (B), the force applied via the rotor 140 causes the knock member 130 to rotate in the return direction, and the knock member 130 stops when the locking protrusion 131 comes into contact with the side of one of the outer cams 120. On the other hand, the fitting member 150 rotates in the same manner while maintaining its position relative to the knock member 130, and then stops (Figure 7 (C)). Therefore, the rotation angle of the fitting member 150, expressed as the distance from the center line c1 in Figure 7, is the distance d2 - d1.

When a knock operation is performed in this state, because the restricting portion 160 has an inclined side surface, the front end of the connecting portion 151 interferes with the restricting portion 160 at point X, as shown in FIG. 7(D). As a result, not only is the knock operation hindered, but there is also a risk that the connecting portion 151 and the restricting portion 160 will become engaged and the knock member 130 will not return to its original position. Therefore, there is a risk that the knock operation will not be performed reliably in the knock-type writing instrument 100. This problem is more pronounced when the engaging member 150 is more firmly engaged with the knock member 130.

The present invention aims to provide a knock-type writing instrument that has a fitting member that fits rotatably around the central axis of the knock member, and that allows a reliable knock operation.

According to one aspect of the present invention, there is provided a knock-type writing instrument comprising a rotor, a knock member that presses the rotor forward and has a locking protrusion on its outer circumferential surface, a fitting member that fits rotatably around the central axis of the knock member and has a restricting protrusion on its outer surface, a restricting portion that restricts the rotation of the fitting member, and a shaft cylinder that is provided with a plurality of cam protrusions that are arranged in the circumferential direction and cooperate with the rotor, and the locking protrusions are arranged between the plurality of cam protrusions, and that is configured such that when the restricting protrusions of the fitting member are rotated in a non-writing state until they come into contact with the restricting portion, the locking protrusions and the cam protrusions do not come into contact with each other.

The engaging member may be engaged with the rear end of the knock member. The engaging member may have a clip.

According to the aspects of the present invention, a knock-type writing instrument that has a fitting member that is rotatably fitted to the knock member around the central axis of the knock member has a common effect of providing a knock-type writing instrument that can perform a reliable knock operation.

FIG. 1 is a vertical cross-sectional view of a knock-type writing instrument according to an embodiment of the present invention in a writing state. FIG. 2 is a cross-sectional view taken along line AA of FIG. FIG. 3 is a schematic diagram showing the relationship between the knock member, the fitting member, and the restricting portion. FIG. 4 is another schematic diagram showing the relationship between the knock member, the fitting member, and the restricting portion. FIG. 5 is a cross-sectional view of a conventional knock-type writing instrument corresponding to FIG. FIG. 6 is a schematic diagram showing the relationship between a knock member, a fitting member, and a restricting portion in a conventional knock-type writing instrument. FIG. 7 is another schematic diagram showing the relationship between the knock member, the fitting member, and the restricting portion in a conventional knock-type writing instrument.

The following describes in detail an embodiment of the present invention with reference to the drawings. Corresponding components are designated by the same reference symbols throughout the drawings.

Figure 1 is a vertical cross-sectional view of a knock-type writing instrument 1 according to an embodiment of the present invention in a writing state, and Figure 2 is a cross-sectional view taken along line A-A in Figure 1.

The knock-type writing instrument 1 has a barrel 4 formed in a cylindrical shape and equipped with a front shaft 2 and a rear shaft 3, a refill 6 which is a writing body arranged in the barrel 4 and equipped with a writing part 5 at one end, a spring 7 which biases the refill 6 backward, and a knock mechanism 10 arranged at the rear end of the barrel 4. The knock mechanism 10 has an outer cam 20 (FIG. 2), a cylindrical knock member 30, a rotor 40, and a fitting member 50 equipped with a connecting part 51 which connects the clip 52. The connecting part 51 constitutes a restricting protrusion. A notch 8 which is cut forward is formed on the rear end surface of the rear shaft 3, and the side of the notch 8 constitutes a restricting part 60. The connecting part 51 is configured to move in the front-rear direction within the notch 8 by a knock operation. In this specification, in the axial direction of the knock-type writing instrument 1, the writing part 5 side is defined as the "front" side, and the opposite side to the writing part 5 side is defined as the "rear" side.

Figure 3 is a schematic diagram showing the relationship between the knock member 30, the engaging member 50, and the regulating portion 60, and Figure 4 is another schematic diagram showing the relationship between the knock member 30, the engaging member 50, and the regulating portion 60. That is, Figures 3 and 4 are schematic diagrams showing the positional relationship of the knock mechanism 10, and show the positions of the locking protrusion 31 of the knock member 30 and the inner cam 41 of the rotor 40, which will be described later, with respect to a partial circumferential development of the outer cam 20 and the regulating portion 60. In the figures, the lower side is the front of the knock type writing instrument 1, and the upper side is the rear of the knock type writing instrument 1.

In detail, outer cams 20, which are cam protrusions constituting part of the knock mechanism 10, are provided at equal intervals along the circumferential direction in front of the restricting portion 60 of the rear axle 3. Adjacent outer cams 20 define a guide groove 21 extending in the front-rear direction. Locking protrusions 31 are provided at equal intervals along the circumferential direction on the outer peripheral surface of the front side of the knock member 30. Each of the locking protrusions 31 is disposed within the guide groove 21 between adjacent outer cams 20. Each of the locking protrusions 31 is configured to move in the front-rear direction within the guide groove 21 by the knock operation. A cam surface 32 is formed on the front end surface of the knock member 30.

The fitting member 50 is fitted to the outer peripheral surface of the rear end of the knock member 30. The inner cams 41, which are protrusions extending in the front-rear direction, are provided on the outer peripheral surface of the rotor 40 at equal intervals in the circumferential direction. For convenience, the inner cams 41 are hatched in the figure, but do not represent a cross section. In the knock-type writing instrument 1 in the non-writing state as shown in FIG. 3, each of the inner cams 41 is disposed in the guide groove 21 of the outer cam 20. The rotor 40 has a cam receiving surface 42 that cooperates with the cam surface 32 of the knock member 30 and has a complementary shape. The rotor 40 is given a rotational force by the cooperation of the cam surface 32 of the knock member 30 and the cam receiving surface 42 of the rotor 40, and rotates around the central axis. The rotor 40 also cooperates with the outer cam 20, contributing to switching between the writing state and the non-writing state. The restricting portion 60 is composed of two side surfaces that are inclined toward each other toward the front in FIG. 3, which shows the restricting portion 60 deployed in the circumferential direction.

Referring to FIG. 3, the rotor 40 is biased backward by the spring 7 via the refill 6, so that the cam surface 32 of the knock member 30 and the cam receiving surface 42 of the rotor 40 cooperate to rotate the knock member 30 to the right and the rotor 40 to the left in the figure. The rotation of the knock member 30 is restricted by the engagement protrusion 31 abutting against the side of one of the outer cams 20, and the rotation of the rotor 40 is restricted by the engagement of the inner cam 41 abutting against the side of the other outer cam 20. At this time, the engagement protrusion 31 and the other outer cam 20 are separated by a distance D1 along the circumferential direction. Also, the connection portion 51 and the restriction portion 60 are separated by a minimum distance D2 along the circumferential direction. The distance D1 is set to be greater than the distance D2.

In FIG. 3, the center line C1 of the cutout portion 8 and the center line C2 of the connection portion 51 are aligned. When a knock operation is performed in this state, the center lines C1 and C2 remain approximately aligned.

From the state shown in Figure 3, when the fitting member 50 is grasped and rotated against the biasing force that rotates the knock member 30, i.e., to the left in the figure, the knock member 30 and the fitting member 50 rotate together around the central axis of the knock member 30. The rotation of the knock member 30 and the fitting member 50 is restricted by the connection portion 51 abutting against the restricting portion 60 (Figure 4). At this time, the amount of rotation of the knock member 30 and the fitting member 50, i.e., the rotation angle, expressed as the distance from the center line C1 in Figure 4, is the above-mentioned distance D2. On the other hand, the locking protrusion 31 and the other outer cam 20 are separated by the distance D1-D2.

Even if further force is applied to the fitting member 50 from the state shown in FIG. 4, the connection portion 51 abuts against the restricting portion 60, so the fitting member 50 cannot be rotated around the central axis of the knock member 30 relative to the knock member 30. Furthermore, when the applied force is released, the knock member 30 and the fitting member 50 rotate due to the biasing force via the rotor 40, and can be returned to their original state (FIG. 3). In short, the knock member 30 and the fitting member 50 will not be misaligned. Therefore, when a knock operation is performed in this state, interference between the front end of the connection portion 51 and the restricting portion 60 cannot occur as shown in FIG. 7 (D), and a reliable knock operation can be performed.

In the conventional knock-type writing implement described above with reference to Figures 5 to 7, it was common sense to make the clearance between the locking protrusion 131 and the outer cam 120, specifically the distance d1, smaller in order to prevent the knock member 130 from rotating or moving in the circumferential direction and rattling when not in use. Therefore, the clearance between the connection part 151 and the regulating part 160, specifically the distance d2, is larger than the distance d1. On the other hand, in the above-mentioned embodiment, contrary to common sense, the distance D1 in Figure 3 is made larger than the distance D2. Note that the distances D1 and D2 may be equal.

The above-mentioned configuration is particularly effective in cases where the fitting member needs to be tightly fitted to the knock member. For example, if the force required to remove the fitting member is set to 50 N to prevent it from coming off the knock member, it is difficult to rotate the fitting member relative to the knock member. However, once it is rotated, it is also difficult to return it to its original position, making it more likely that the above-mentioned problem will occur. Even in such cases, the problem of the knock operation not being able to be performed reliably can be prevented by configuring the distance D1 in FIG. 3 to be greater than the distance D2.

In the above embodiment, the fitting member 50 is configured to have a clip 52 provided via the connection portion 51, but it may be configured without a clip, with a simple protrusion corresponding to the connection portion moving in the front-rear direction within the cutout portion. The fitting member may also be fitted to the central portion in the axial direction, rather than the rear end portion of the knock member, and in this case, the cutout portion may be a rectangular opening provided on the side of the barrel. The restricting portion is an inclined side surface of the cutout portion, but it may be configured as desired as long as it allows the connection portion to move in the front-rear direction and restricts rotation. For example, the restricting portion may be a side surface that extends along the axial direction without being inclined. In short, the fitting member, the restricting portion, and even the restricting protrusion may be configured as desired as long as it is configured so that the locking protrusion and the outer cam (cam protrusion) do not come into contact with each other when the connection portion (restricting protrusion) of the fitting member is rotated until it abuts on the restricting portion in a non-writing state.

The refill 6 may be a ballpoint pen or other type of writing instrument such as a marking pen, a touch pen, or an eraser. In addition, a part or all of the fitting member 50 may be an erasing section that erases handwriting made with a knock-type writing instrument.

The refill 6 may be a ballpoint pen containing thermochromic ink. Here, thermochromic ink refers to ink that maintains a certain color (first color) at room temperature (e.g., 25°C), changes to another color (second color) when heated to a certain temperature (e.g., 60°C), and then returns to the original color (first color) when cooled to a certain temperature (e.g., -5°C). In a thermochromic writing instrument using thermochromic ink, the second color is made colorless, and the term "erasing" refers to heating a line drawn in the first color (e.g., red) to make it colorless. Therefore, the friction member, which is the erasing part, rubs against the writing surface on which the line was drawn to generate frictional heat, which changes the drawn line to colorless, that is, erases it. Of course, the second color may be a color other than colorless.

REFERENCE SIGNS LIST 1 Knock-type writing implement 2 Front barrel 3 Rear barrel 4 Barrel 5 Writing portion 6 Refill 7 Spring 8 Cutout portion 10 Knock mechanism 20 Outer cam 21 Guide groove 30 Knock member 31 Locking protrusion 32 Cam surface 40 Rotor 41 Inner cam 42 Cam receiving surface 50 Fitting member 51 Connection portion 52 Clip 60 Regulating portion

Claims (3)

A rotor;
a knock member that presses the rotor forward and has an engaging protrusion on an outer circumferential surface;
a fitting member that is fitted to the knock member so as to be rotatable about a central axis of the knock member and has a restricting protrusion on an outer surface thereof;
a restricting portion that restricts rotation of the fitting member; and a shaft cylinder that is provided with a plurality of cam protrusions that are arranged along a circumferential direction and cooperate with the rotor, and the locking protrusion portion is arranged between the plurality of cam protrusions,
A knock-type writing instrument characterized in that, when the regulating protrusion of the engaging member is rotated relative to the knock member until it abuts against the regulating portion in a non-writing state, the locking protrusion portion and the cam protrusion are configured not to abut against each other. The knock-type writing instrument according to claim 1, wherein the fitting member is fitted to the rear end of the knock member. 3. The knock-type writing implement according to claim 1, wherein the fitting member has a clip, and the restricting projection is a connection portion that connects the clip and the fitting member .

Images