JP7556728B2 - Knock-type writing instrument - Google Patents

Description

The present invention relates to a knock-type writing instrument that has a structure in which a rotating cam slides and rotates when a fixed cam is pushed, causing the writing tip of the writing body to appear and disappear from a tip connected to the front of the barrel.

Conventionally, knock-type writing instruments such as the one described in JP 11-78361 A are well known in which a rotating cam slides and rotates when a fixed cam is pushed, causing the writing tip of a writing object such as a ballpoint pen refill to appear and disappear from a tip connected to the front of the barrel. Such knock-type writing instruments make it possible to replace a writing object such as a ballpoint pen refill housed in the barrel by attaching and detaching the tip connected to the front of the barrel, or by attaching and detaching the front barrel from the rear barrel.

However, since there are many types of writing bodies that can be stored in the barrel of a writing instrument, if versatility is required from a cost perspective, a structure that allows multiple writing bodies to be selectively stored in a common barrel and a common tip connected to it is preferable. This is advantageous not only for differences in writing color, such as writing color, but also for differences in the outer diameter of the writing body due to differences in the writing tip, which affects the thickness of the writing, by being able to store at least two types of writing bodies in a common barrel and a common tip connected to it.

Japanese Patent Application Publication No. 11-78361

The purpose of this invention is to make it possible to accommodate multiple writing bodies with different outer diameters in a common barrel and a common tip connected to it.

The present invention relates to
"1.
The tip is detachably connected to the front of the barrel.
The writing body contained in the barrel is repelled backward by a coil spring engaged with the tip,
a fixed cam having a sliding protrusion that can slide along a plurality of cam grooves provided in the shaft cylinder, and a rotating cam having a locking protrusion that rotates by sliding along the cam grooves in front of the fixed cam and is locked to a locking portion provided at a front end of the cam groove,
the fixed cam and the rotating cam are arranged in a vertical line such that a meshed portion formed on the rotating cam meshes with a concave-convex meshing portion formed on a sliding protrusion of the fixed cam and configured with an inclined surface with respect to an axial direction, the meshed portion being meshed with a meshed portion formed on the rotating cam,
A knock-type writing instrument having a structure in which the fixed cam is pushed to slide the rotating cam, and the writing tip of the writing body housed in the barrel is caused to appear and disappear from the tip as the rotating cam rotates,
The inner circumferential surface of the tip opening is formed in a tapered shape, a first locking portion is formed on the inner circumferential surface of the tip opening, and a second locking portion having a larger diameter than the first locking portion is formed behind the first locking portion,
a first coil spring can be engaged with a first locking portion of the tip opening, a second coil spring having a diameter larger than that of the first coil spring can be engaged with a second locking portion of the tip opening, and a first writing body inserted into the first coil spring engaged with the first locking portion or a second writing body inserted into the second coil spring engaged with the second locking portion can be selectively accommodated in the barrel;
A knock-type writing instrument characterized in that when a second writing body is inserted into a first coil spring engaged with a first engagement portion of the tip, or when a first writing body is inserted into a second coil spring engaged with a second engagement portion of the tip, and the fixed cam is pushed to slide the rotating cam, the first coil spring or the second coil spring is fully compressed, thereby restricting the forward movement of the fixed cam and making it impossible for the writing tip of the writing body to protrude or retract from the tip.
2.
The knock-type writing instrument according to claim 1, wherein the writing tip of the second writing body has a smaller diameter than the writing tip of the first writing body.

The knock-type writing instrument of the present invention can accommodate two types of writing bodies with different outer diameters due to differences in the writing tips, etc., in a common tip and a common barrel that connects to it.

In addition, even if the writing tip of the second cursive body has a smaller diameter than the writing tip of the first cursive body, the writing tip of the second cursive body is inserted into the second coil spring, which has a larger diameter than the first coil spring, so that the writing tip of the second cursive body is less likely to come into contact with the second coil spring when inserted compared to the small diameter first coil spring, improving assembly.

In addition, when the fixed cam is pushed to slide the rotating cam while the second writing body is inserted through the first coil spring engaged with the first locking portion of the tip cap, or when the first writing body is inserted through the second coil spring engaged with the second locking portion of the tip cap, the first coil spring and the second coil spring are fully compressed, restricting the forward movement of the fixed cam and making it impossible for the writing tip of the writing body to appear or disappear from the tip cap. This makes it possible to detect if the parts have been assembled incorrectly by performing a knocking operation during assembly.

FIG. 1 is a vertical cross-sectional view of the ballpoint pen of the present embodiment in a first state in which a first ballpoint pen refill is inserted into a first coil spring engaged with the tip of the ballpoint pen, and in which the writing tip is retracted. FIG. 2 is a diagram showing a part of a ballpoint pen in a first state with the tip removed from the barrel. FIG. 3 is a vertical cross-sectional view of the ballpoint pen of this embodiment in a second state in which a second ballpoint pen refill is inserted into a second coil spring engaged with the tip of the ballpoint pen, and in which the writing tip is retracted. FIG. 4 is a diagram showing a part of the ballpoint pen in the second state with the tip removed from the barrel. FIG. 5 is a vertical cross-sectional view of the ballpoint pen in a first state, in which the writing tip of the first ballpoint pen refill protrudes from the tip opening. FIG. 6 is a vertical cross-sectional view of the ballpoint pen in the second state, in which the writing tip of the second ballpoint pen refill protrudes from the tip opening. FIG. 7 is a diagram showing a schematic diagram of the cam operation of the ballpoint pen in a first state and a second state, where FIG. 7A shows the state in which the writing tip is retracted, and FIG. 7B shows the state in which the writing tip is protruding. FIG. 8 is a vertical cross-sectional view of the ballpoint pen in a third state in which the second ballpoint pen refill is inserted into the first coil spring engaged with the tip opening, and in which the writing tip is retracted. FIG. 9 is a vertical cross-sectional view of the ballpoint pen in a fourth state in which the first ballpoint pen refill is inserted into the second coil spring engaged with the tip opening, and in which the writing tip is retracted. FIG. 10 is a vertical cross-sectional view of the ballpoint pen in a third state, in which the writing tip of the second ballpoint pen refill is about to be projected from the tip opening. FIG. 11 is a vertical cross-sectional view of the ballpoint pen in a fourth state, in which the writing tip of the first ballpoint pen refill is about to be protruded from the tip opening. Figure 12 is a schematic diagram showing the cam operation of the ballpoint pen in the third and fourth states, where Figure 12A shows the state in which the writing tip is retracted, and Figure 12B shows the state in which the writing tip is about to protrude from the tip.

The knock-type ballpoint pen of this embodiment will be described below with reference to the drawings. In this embodiment, a knock-type ballpoint pen using a rotating cam mechanism as a pen tip extension mechanism will be described, but the present invention is not limited to the knock-type ballpoint pen described below, and can also be used in knock-type writing instruments such as fountain pens, marking pens, and mechanical pencils.
In this embodiment, the side where the writing tip is located is referred to as the "front" and the opposite side is referred to as the "rear." For ease of understanding, the same reference numerals are used to refer to similar members and portions in the drawings.

Fig. 1 is a vertical cross-sectional view of a knock-type ballpoint pen according to the present embodiment, showing a first state in which a first ballpoint pen refill is inserted into a first coil spring engaged with a tip end, and a writing tip end is retracted. Fig. 2 is a diagram showing a part of the ballpoint pen in the first state with the tip end removed from the barrel.
In the first state, the ballpoint pen 1A has a body 4 formed by a tip 3 detachably connected to the front of a barrel 2, a first ballpoint pen refill 5A (first writing body) housed in the barrel 2 is resilient rearward by a first coil spring 6A engaged with the tip 3, a fixed cam 7 having a sliding protrusion 7a that can slide along a plurality of cam grooves 2a provided in the barrel 2, and a rotating cam 8 having a locking protrusion 8a that rotates in front of the fixed cam 7 while sliding along the cam groove 2a and is locked with a locking portion 2b provided at the front end of the cam groove 2a. The fixed cam 7 and the rotating cam 8 are vertically arranged such that a meshed portion 8b formed on the rotating cam 8 meshes with a meshing portion 7b formed on the fixed cam 7, the meshed portion 8b meshing with the meshing portion 7b formed on the rotating cam 8.
In the first state, the ballpoint pen 1A slides the rotating cam 8 by pushing the fixed cam 7, and as the rotating cam 8 rotates, the writing tip 51A of the first ballpoint pen refill 5A housed in the barrel 2 appears and disappears from the tip opening 3.

Fig. 3 is a vertical cross-sectional view of the knock-type ballpoint pen of the present embodiment, showing a second state in which a second ballpoint pen refill is inserted into a second coil spring engaged with a tip end, and the writing tip end is retracted. Fig. 4 is a diagram showing a part of the ballpoint pen in the first state with the tip end removed from the barrel.
In the ballpoint pen 1B in the second state, a tip 3 is detachably connected to the front of a barrel 2 to form a main body 4, and a second ballpoint pen refill 5B (second writing body) housed in the barrel 2 is resilient backward by a second coil spring 6B engaged with the tip 3. Other points are the same as those of the ballpoint pen 1A in the first state, and therefore will not be described.
In the ballpoint pen 1B, the fixed cam 7 is pushed to slide the rotating cam 8, and as the rotating cam 8 rotates, the writing tip 51B of the second ballpoint pen refill 5B housed in the barrel 2 appears and disappears from the tip opening 3.

In addition, the tip opening 3 has an inner surface 3b rearward of the tip opening 3a formed in a gradually tapered shape, a first locking portion 3c is formed on the inner surface 3b, and a second locking portion 3d having a larger diameter than the first locking portion 3c is formed rearward of the first locking portion 3c.
In the ballpoint pen 1A in the first state shown in Fig. 1, a first coil spring 6A is engaged with a first engagement portion 3c of the tip 3, and a first ballpoint pen refill 5A is inserted through the first coil spring 6A. In the ballpoint pen 1B in the second state shown in Fig. 3, a second coil spring 6B is engaged with a second engagement portion 3d of the tip 3, and a second ballpoint pen refill 5B is inserted through the second coil spring 6B.
As shown in FIGS. 2 and 4, the second coil spring 6B of the ballpoint pen 1B in the second state has a larger diameter and a longer natural length than the first coil spring 6A of the ballpoint pen 1A in the first state.
This makes it difficult for the writing tip 51B of the second ballpoint pen refill 5B, which has a smaller diameter than the writing tip 51A of the first ballpoint pen refill 5A, to come into contact with the second coil spring 6B when inserted, improving ease of assembly.
In the present invention, the diameter of the second coil spring being larger than the diameter of the first coil spring refers to a state in which both the outer diameter and the inner diameter are larger.

Next, the operation of projecting the writing tip from the tip opening will be described with reference to Figs. 5 to 7 .
Fig. 5 is a vertical cross-sectional view of a ballpoint pen in a first state, in which the writing tip of the first ballpoint pen refill protrudes from the tip. Fig. 6 is a vertical cross-sectional view of a ballpoint pen in a second state, in which the writing tip of the second ballpoint pen refill protrudes from the tip. Fig. 7 is a diagram showing the cam operation of the ballpoint pen in the first and second states, in which Fig. 7A shows the writing tip retracted and Fig. 7B shows the writing tip protruding.
The ballpoint pen 1A in the first state (ballpoint pen 1B in the second state) is provided with a conventional rotating cam mechanism that is activated by a knock operation, at the rear of the barrel 2. The rotating cam mechanism is composed of cam grooves 2a formed at equal intervals on the circumference of the inner surface 22a of the barrel 2, the cylindrical fixed cam 7 protruding from a rear end opening 22c formed at the rear end of the barrel 2, and the cylindrical rotating cam 8 disposed in front of the fixed cam 7.
The fixed cam 7 has a concave-convex meshing portion 7b at its tip, and a plurality of sliding projections 7a that engage with the cam groove 2b are provided on its outer surface at equal intervals on the circumference so as to be located at the tops 7c of the meshing portion 7b.
The outer peripheral surface of the rotating cam 8 has a plurality of locking projections 8a which engage with the cam groove 2a, and the rear ends of the locking projections 8a are provided with meshed portions 8c which are constituted by inclined surfaces 8b which mesh with the meshing portions 7b of the fixed cam 7.

As shown in FIG. 7A, the cam mechanism of this embodiment is designed so that when the sliding protrusion 7a of the fixed cam 7 and the locking protrusion 8a of the rotating cam 8 are engaged with the cam groove 2a, the apex 7c of the meshing portion 7b of the fixed cam 7 is positioned at the midpoint of the inclined surface 8b of the meshed portion 8c of the rotating cam 8.

In the ballpoint pen 1A in the first state shown in Figure 1, when the knock portion 7d of the fixed cam 7 protruding from the rear end opening 22c of the barrel 2 is pushed forward on the barrel 2, the fixed cam 7 moves forward guided by the sliding protrusion 7a engaged with the deep cam groove 221a and shallow cam groove 222a formed on the inner surface 22a of the barrel 2, and the rotating cam 8 connected to the fixed cam 7 moves forward guided by the locking protrusion 8a engaged with the deep cam groove 221a (see Figure 7).
When the locking projection 8a reaches the tip of the deep cam groove 221a and disengages from the cam groove, the top 7c of the meshing portion 7b of the fixed cam 7 is located at the middle of the inclined surface 8b of the meshed portion 8c of the rotating cam 8. At this time, the rotating cam 8 is in contact with the first ballpoint pen refill 5A that is resiliently pushed backward by the first coil spring 6A engaged with the tip opening 3, so that it rotates from right to left in an attempt to retreat backward (because the inclined surface 8b of the meshed portion 8c slopes downward to the right in the figure), and the meshed portion 8c of the rotating cam 8 slides along the meshing portion 7b of the fixed cam 7, and the meshed portion 8c of the locking projection 8a is locked to the locking inclined surface 223a at the tip of the shallow cam groove 222a, so that the writing tip 51A can be maintained in a state of protruding from the tip opening 3a as shown in FIG.
Furthermore, by again pushing the knock portion 7d of the fixed cam 7 toward the front of the barrel 2, the engagement between the meshed portion 8c of the locking protrusion 8a and the locking inclined surface 223a of the shallow cam groove 222a is released, and the rotating cam 8, which is spring-loaded by the first coil spring 6A, rotates from right to left in an attempt to retreat (because the inclined surface 8b of the meshed portion 8c slopes downward to the right in the figure), and the locking protrusion 8a of the rotating cam 8 retreats through the deep cam groove 221a to the state shown in Figure 7A, with the writing tip 51A immersed in the tip opening 3a as shown in Figure 1.
In the ballpoint pen 1A in the first state shown in Figure 1, when the knock mechanism is activated, the first coil spring 6A is not fully compressed, and the meshed portion 8c escapes from the deep cam groove 221a, allowing the rotating cam 8 to rotate.

In the ballpoint pen 1B in the second state shown in Figure 3, when the knock portion 7d of the fixed cam 7 protruding from the rear end opening 22c of the barrel 2 is pushed forward on the barrel 2, the fixed cam 7 moves forward guided by the sliding protrusion 7a engaged with the deep cam groove 221a and shallow cam groove 222a formed on the inner surface 22a of the barrel 2, and the rotating cam 8 connected to the fixed cam 7 moves forward guided by the locking protrusion 8a engaged with the deep cam groove 221a (see Figure 7).
When the locking projection 8a reaches the tip of the deep cam groove 221a and disengages from the cam groove, the top 7c of the meshing portion 7b of the fixed cam 7 is located at the midpoint of the inclined surface 8b of the meshed portion 8c of the rotating cam 8. At this time, the rotating cam 8 is in contact with the second ballpoint pen refill 5B that is resiliently pushed backward by the second coil spring 6B engaged with the tip opening 3, so that it rotates from right to left in an attempt to retreat backward (because the inclined surface 8b of the meshed portion 8c slopes downward to the right in the figure), and the meshed portion 8c of the rotating cam 8 slides along the meshing portion 7b of the fixed cam 7, and the meshed portion 8c of the locking projection 8a is locked to the locking inclined surface 223a at the tip of the shallow cam groove 222a, so that the writing tip 51B can be maintained in a state of protruding from the tip opening 3a as shown in FIG.
Furthermore, by again pushing the knock portion 7d of the fixed cam 7 toward the front of the barrel 2, the engagement between the meshed portion 8c of the locking protrusion 8a and the locking inclined surface 223a of the shallow cam groove 222a is released, and the rotating cam 8, which is spring-loaded by the second coil spring 6B, rotates from right to left in an attempt to retreat (because the inclined surface 8b of the meshed portion 8c slopes downward to the right in the figure), and the locking protrusion 8a of the rotating cam 8 retreats through the deep cam groove 221a to the state shown in Figure 7A, and the writing tip 51B is immersed in the tip opening 3a as shown in Figure 3.
In the ballpoint pen 1B in the first state shown in Figure 3, when the knock mechanism is activated, the second coil spring 6B is not fully compressed, and the meshed portion 8c escapes from the deep cam groove 221a, allowing the rotating cam 8 to rotate.

Figure 8 is a vertical cross-sectional view of a ballpoint pen in a third state in which a second ballpoint pen refill is inserted into a first coil spring engaged with the tip opening, and the writing tip is retracted. Figure 9 is a vertical cross-sectional view of a ballpoint pen in a fourth state in which a first ballpoint pen refill is inserted into a second coil spring engaged with the tip opening, and the writing tip is retracted. Figure 10 is a vertical cross-sectional view of a ballpoint pen in a third state in which the writing tip of the second ballpoint pen refill is about to protrude from the tip opening. Figure 11 is a vertical cross-sectional view of a ballpoint pen in a fourth state in which the writing tip of the first ballpoint pen refill is about to protrude from the tip opening. Figure 12 is a diagram showing the cam operation of a ballpoint pen in the third and fourth states, where Figure 12A shows the writing tip retracted and Figure 12B shows the writing tip protruding from the tip opening.

The ballpoint pen 1C in the third state shown in Figures 8 and 10 has a first coil spring 6A engaged with the first engagement portion 3c of the tip 3, and a second ballpoint pen refill 5B inserted through the first coil spring 6A. The ballpoint pen 1D in the fourth state shown in Figures 9 and 11 has a second coil spring 6B engaged with the second engagement portion 3d of the tip 3, and a first ballpoint pen refill 5A inserted through the second coil spring 6B.

In the ballpoint pen 1C in the third state shown in Fig. 8, when the knock portion 7d of the fixed cam 7 protruding from the rear end opening 22c of the barrel 2 is pushed forward of the barrel 2, the fixed cam 7 advances guided by the sliding protrusion 7b engaged with the deep cam groove 221a and the shallow cam groove 222a formed on the inner surface 22a of the barrel 2, and the rotating cam 8 connected to the fixed cam 7 advances guided by the locking protrusion 8a engaged with the deep cam groove 221a (see Fig. 12). At this time, as in the ballpoint pen 1C in the third state shown in Fig. 10, the first coil spring 6A is fully compressed, so that the knock operation is interrupted, and as shown in Fig. 12B, the inclined surface 8c of the meshed portion 8b of the locking protrusion 8a does not reach the tip of the deep cam groove 221a, and as a result, the rotating cam 8 cannot rotate, and the writing tip 51B of the second ballpoint pen refill 5B cannot maintain a state protruding from the tip 3.

In the ballpoint pen 1D in the fourth state shown in Fig. 9, when the knock portion 7d of the fixed cam 7 protruding from the rear end opening 22c of the barrel 2 is pushed forward of the barrel 2, the fixed cam 7 advances guided by the sliding protrusion 7b engaged with the deep cam groove 221a and the shallow cam groove 222a formed on the inner surface 22a of the barrel 2, and the rotating cam 8 connected to the fixed cam 7 advances guided by the locking protrusion 8a engaged with the deep cam groove 221a (see Fig. 12). At this time, as in the ballpoint pen 1D in the fourth state shown in Fig. 11, the second coil spring 6B is fully compressed, so that the knock operation is interrupted, and as shown in Fig. 12B, the inclined surface 8b of the meshing portion 8c of the locking protrusion 8a does not reach the tip of the deep cam groove 221a, and as a result, the rotating cam 8 cannot rotate, and the writing tip 51A of the first ballpoint pen refill 5A cannot maintain a state protruding from the tip end 3.

The first ballpoint pen refill 5A and the second ballpoint pen refill 5B are both provided with abutment parts 52A, 53A, 52B, 53B that can abut against either the first coil spring 6A or the second coil spring 6B, and can be housed within the barrel 2. However, because the coil springs corresponding to each ballpoint pen refill are not properly engaged in the tip 3, each coil spring is fully compressed during the knock operation, and the knock operation is interrupted before the operation of the rotating cam is completed, resulting in a structure in which the writing tip of the writing element cannot maintain a state protruding from the tip, and it is possible to recognize that the components are assembled incorrectly.

In this embodiment, the position where the first coil spring 6A is engaged with the first engaging portion 3c of the tip opening 3 and the abutment portion 53B of the second ballpoint pen refill 5B abuts against the rear end of the first coil spring 6A (see FIG. 8) is further forward than the position where the first coil spring 6A is engaged with the first engaging portion 3c of the tip opening 3 and the abutment portion 52A of the first ballpoint pen refill 5A abuts against the rear end of the first coil spring 6A (see FIG. 1). As a result, in the ballpoint pen 1C in the third state shown in FIG. 8, even when the writing tip 51B is retracted, the first coil spring 6A is already compressed more than in the state shown in FIG. 1, and during a knock operation, the first coil spring 6A is fully compressed before the cam operation of the rotating cam mechanism is completed, and the knock operation is interrupted.
Furthermore, the position where the second coil spring 6B is engaged with the second engaging portion 3d of the tip opening 3 and the abutment portion 53A of the first ballpoint pen refill 5A is in contact with the rear end of the second coil spring 6B (see FIG. 9) is further forward than the position where the second coil spring 6B is engaged with the second engaging portion 3d of the tip opening 3 and the abutment portion 52B of the second ballpoint pen refill 5B is in contact with the rear end of the second coil spring 6B (see FIG. 3). As a result, in the ballpoint pen 1C in the third state shown in FIG. 9, even when the writing tip 51B is retracted, the second coil spring 6B is already compressed to a greater extent than in the state shown in FIG. 3, and during a knock operation, the second coil spring 6B is fully compressed before the cam action of the rotating cam is completed, causing the knock operation to be interrupted.

1A: Ballpoint pen in first state; 1B: Ballpoint pen in second state;
1C...ballpoint pen in third state, 1D...ballpoint pen in fourth state,
2... Shaft cylinder, 2a... Cam groove, 2b... Locking part,
22a... inner surface, 221a... deep cam groove, 222a... shallow cam groove, 223a... engaging inclined surface,
22c...rear end opening,
3...Tip opening, 3a...Tip opening, 3b...Inner peripheral surface, 3c...First locking part, 3d...Second locking part,
4...Main body,
5A...first ballpoint pen refill, 51A...writing tip, 52A...contact portion, 53A...contact portion,
5B... second ballpoint pen refill, 51B... writing tip, 52B... abutment portion, 53B... abutment portion,
6A…first coil spring,
6B: second coil spring,
7: fixed cam, 7a: meshing portion, 7b: sliding projection, 7c: top portion, 7d: knock portion,
8... Rotating cam, 8a... Locking protrusion, 8b... Inclined surface, 8c... Engaged portion.

Claims (2)

The tip is detachably connected to the front of the barrel.
The writing body contained in the barrel is repelled backward by a coil spring engaged with the tip,
a fixed cam having a sliding protrusion that can slide along a plurality of cam grooves provided in the shaft cylinder, and a rotating cam having a locking protrusion that rotates by sliding along the cam grooves in front of the fixed cam and is locked to a locking portion provided at a front end of the cam groove,
the fixed cam and the rotating cam are arranged in a vertical line such that a meshed portion formed on the rotating cam meshes with a concave-convex meshing portion formed on a sliding protrusion of the fixed cam and configured with an inclined surface with respect to an axial direction, the meshed portion being meshed with the meshing portion formed on the rotating cam;
A knock-type writing instrument having a structure in which the fixed cam is pushed to slide the rotating cam, and the writing tip of the writing body housed in the barrel is caused to appear and disappear from the tip as the rotating cam rotates,
The inner circumferential surface of the tip opening is formed in a tapered shape, a first locking portion is formed on the inner circumferential surface of the tip opening, and a second locking portion having a larger diameter than the first locking portion is formed behind the first locking portion,
A first coil spring can be engaged with a first locking portion of the tip opening, a second coil spring can be engaged with a second locking portion of the tip opening, and a first writing body inserted into the first coil spring engaged with the first locking portion or a second writing body inserted into the second coil spring engaged with the second locking portion can be selectively accommodated in the barrel ,
A knock-type writing instrument characterized in that when a second writing body is inserted into a first coil spring engaged with a first engagement portion of the tip, or when a first writing body is inserted into a second coil spring engaged with a second engagement portion of the tip, and the fixed cam is pushed to slide the rotating cam, the first coil spring or the second coil spring is fully compressed, thereby restricting the forward movement of the fixed cam and making it impossible for the writing tip of the writing body to retract from the tip. 2. The knock-type writing implement according to claim 1, wherein the tip of the second writing body has a smaller diameter than the tip of the first writing body.

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