JP3517843B2 - Writing implement - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument such as a ball pen having a rotary cam mechanism.

[0002]

2. Description of the Related Art A variety of writing instruments are known in which the tip of a refill housed in a barrel is made to appear and disappear from a mouthpiece at the tip of the barrel by means of a rotating cam mechanism. As is well known, this rotary cam mechanism is mainly composed of three members: an outer cam barrel (fixed cam), a rotor and a knock cam. The outer cam cylinder is integrally formed in the shaft cylinder or is separately formed and fixed in the shaft cylinder, and a cam groove having deep grooves and shallow grooves extending in the axial direction alternately in the circumferential direction, and the cam groove of the cam groove. It has a cam surface formed on the front end side. The rotor has a protrusion to be inserted into a cam groove of the outer cam barrel and a cam surface formed at a rear end of the protrusion to engage with a cam surface of the outer cam barrel. It is provided to be movable. The knock cam has a cam surface at a front end so as to engage with the cam surface of the rotor, has a projection on the peripheral surface to be inserted into the cam groove of the outer cam cylinder, and is provided so as to be movable in the axial direction. ing. The refill is spring-biased so that its rear end contacts the rotor.

With the above construction, when the knock cam is pushed against the spring of the refill to move it forward, the protrusion of the rotor, which is inserted into the deep cam groove, comes out of the cam groove. Pushed to a position, rotated by the action of the rotor and the cam surface of the knock cam, and the projection is engaged with the cam surface of the outer cam cylinder at a position corresponding to the cam groove of the shallow groove and is held at the forward position. The tip of the refill projects from the base. When the knock cam is knocked again, the rotor advances beyond the cam surface of the outer cam cylinder, the rotor is rotated by the knock cam and the cam surface of the rotor, and when the knock is stopped, the refill is urged. Due to the action of the spring, the rotor and the like retract, the protrusions of the rotor enter the deep groove of the cam groove, the rotor is held in the retracted position, the refill retracts, and the tip of the reef sinks into the base. To do.

Some of the above-mentioned knock cams have a rear end which is directly knocked, but normally, a knock button, a knock cover, a knock cap and the like (hereinafter referred to as a knock cap) are attached to the rear end so as to facilitate the knocking operation. There are many. This assembling work is performed by forming a mounting hole in the knock cap, applying the mounting hole to the rear of the shaft portion of the knock cam, and pushing the knock cap in the axial direction. If the press-fitting at this time is insufficient, the refill cannot be properly retracted during use. Also, the front end of the knock cam must be pressed so that the knock cam does not move forward during press fitting, but at this time, if the cam surface of the knock cam is strongly pressed, the cam surface is damaged, and the cam surface operates as described above. Since it is a main member at that time, it may not be able to operate smoothly.

[0005]

The problems to be solved by the present invention are as follows.
In a writing instrument having a rotary cam mechanism as described above, when assembling the knock cap, insufficient press-fitting occurs,
It is an object of the present invention to provide a writing instrument in which the cam surface is not damaged.

[0006]

According to the present invention, in a writing instrument having a rotating cam mechanism including an outer cam barrel, a rotor and a knock cam, a mounting barrel portion extending rearward is formed in the outer cam barrel, and the mounting barrel There is provided a writing instrument characterized in that a knock cap is slidably fitted to the portion, and a knock cam pressing portion facing the rear end of the knock cam is provided in the knock cap, and the above problem is solved.

Further, according to the present invention, in the above-mentioned writing instrument, the knock cap is prevented from coming off from the mounting cylinder portion so as to stop at the retracted position, and is biased by the return spring toward the retracted position. The writing instrument according to the present invention is provided to solve the above problems.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention can be applied to various writing instruments having a writing tip which is projected and retracted. However, in the drawings, a writing instrument having a ball pen refill is described as an example. . As shown in FIG. 1, the barrel (1) has a base (2) at its tip, a refill (3) is inserted inside, and the refill (3) is moved backward by a spring (4). I am urged. The base (2) is removably attached to the shaft cylinder (1) by screwing, press fitting, concavo-convex engagement or the like, but may be integrally formed with the shaft cylinder (1). it can.

A rotary cam mechanism is provided in the shaft cylinder. Although various configurations of the rotary cam mechanism are known, as described above, all of the mechanisms basically include the outer cam barrel (fixed cam) (5), the rotor (6) and the knock cam (7). It consists of one member.

The outer cam cylinder (5) is formed in a substantially cylindrical shape,
The inner surface has a cam groove (8) in which deep grooves and shallow grooves are alternately formed in the circumferential direction, a cam surface (9) is formed on the front end side of the cam groove, and extends rearward via a shoulder portion (38). It has a mounting tube portion (10). The outer cam cylinder (5) is screwed into the shaft cylinder (1),
It can be fixed by press fitting, concave-convex engagement, or any other suitable fixing method. In FIGS. 1 to 5, the front end of the outer cam barrel (5) is brought into contact with the inner step portion (11) projecting in the shaft cylinder, and the inner projection (12) projecting in the shaft cylinder is crossed. The outer projection (13) formed on the outer periphery of the outer cam cylinder is engaged with the outer cam cylinder to fix the outer cam cylinder. Although the inner protrusion and the outer protrusion are formed in an annular shape, either one of the protrusions may be formed partially in the circumferential direction.

6 and 7 show another fixing method, in which the rear inner diameter of the inner step portion (11) in the barrel (1) is sequentially enlarged to form a plurality of expanded portions (14), (15). ), (16) are formed, and each of the expanded diameter portions is provided with an inward projection (17), (18), (19) having an arcuate cross section. On the other hand, on the outer circumference of the outer cam barrel (5), the outer diameter is gradually increased corresponding to the enlarged diameter portion via the guide surface (20) that is inclined so as to have a larger diameter from the front side toward the rear side. A plurality of claw-shaped outward projections (21), (22), (23) are formed. Therefore,
Since the outer diameter of the outer protrusion on the front side is smaller than the outer diameter of the outer protrusion on the rear side, the outer cam barrel (5) is connected to the shaft barrel (1).
When inserting from the rear end, the outer protrusion on the front side does not hit the inner protrusion on the rear side and can be inserted easily. Engage with the protrusion. In this way, the stress acting on the outer protrusions and the like is reduced, and scratches and cracks due to changes with time are reduced.

Inside the outer cam barrel (5), there are a protrusion (24) inserted into the cam groove (8) of the outer cam barrel (5) and a cam surface (9) of the outer cam barrel (5). The rotor (6) having a cam surface (25) that engages with is inserted from the front of the outer cam barrel. The knock cam (27) having a projection (26) inserted into the cam groove (8) of the outer cam barrel (5) and a cam surface (27) engaging with the cam surface (25) of the rotor (6) ( 7) is inserted into the outer cam cylinder from the front of the outer cam cylinder (5) before inserting the rotor (6), and the shaft portion (28) formed on the knock cam (7) is the mounting cylinder. It extends into the part (10). At this time, since the rear end of the refill (3) is biased rearward by the spring (4), the rear end of the refill (3) is in contact with the rotor (6). You may make it fit.

The mounting cylinder portion (10) of the outer cam cylinder (5) is
A knock cap (29) is slidably fitted therein, and a knock cam pressing portion (30) is provided in the knock cap (29) so as to face the rear end of the knock cam (7). In the figure, the knock cap (29) has a mounting hole (31) so as to be fitted to the outer side of the mounting tubular portion (10), and the mounting hole (31) is provided at the rear end of the mounting tubular portion (10). It is attached to the mounting cylinder by pressing and pushing it, but the front part of the knock cap is formed into an inner diameter that can be inserted inside the mounting cylinder (10) and the knock cap is inserted inside the mounting cylinder. You may do it. Although the knock cap is assembled to the outer cam barrel before fixing the outer cam barrel to the shaft barrel, the knock cap may be attached to the outer cam barrel after fixing the outer cam barrel to the shaft barrel. Good.

The knock cap (29) is movable in the axial direction back and forth, and preferably, in the retracted position, is prevented from coming off from the mounting cylinder portion (10). In the figure, a guide ridge (32) extending in the axial direction is formed on the mounting cylinder (10), an enlarged head (33) is provided at the rear end of the guide ridge (32), and the knock cap ( 29) said guide ridge (3
The opening groove (34) through which 2) is inserted and the window portion (35) into which the enlarged head portion (33) is fitted are formed, and the enlarged head portion (33) is located at the inner end of the opening groove (34) in the retracted position. The knock cap is prevented from coming off by abutting. In addition, the opening groove of the knock cap (29)
The outer end of (34) and the corner of the enlarged head (33) are formed with slopes so that the knock cap can be easily inserted into the mounting cylinder. Further, instead of the above configuration, an appropriate retaining member such as a flange or a protrusion may be provided.

The knock cam pressing portion (30) extends so as to project from the inner bottom (36) of the knock cap (29) in the axial direction, and its tip end faces the shaft portion (28) extending rearward of the knock cam (7). is doing. The length of the knock cam pressing portion (30) and the shaft portion (28) of the knock cam (7) can be set to an appropriate length. For example, by shortening the knock cam pressing portion, the inner bottom of the knock cap (29) ( 36) itself as a knock cam pressing portion, the shaft portion (28) of the knock cam is extended to a portion facing the inner bottom (36), and the knock cam pressing portion (30) is used as the outer cam cylinder (5). The shaft portion (28) may be formed to be short by extending deeply inside the mounting cylinder portion (10).

The above-mentioned knock cap (29) can be moved to the forward movement position and the backward movement position along the mounting cylinder portion (10) of the outer cam cylinder (5) by the above-mentioned structure, but the knock cap (29) can be moved as desired. 29) may be biased by the return spring (37) toward the retracted position. In this way, when not knocking, the knock cap is always in the retracted position and the appearance is good, and there is no rattling. In FIG. 8, the return spring (37) is provided between the inner bottom (36) of the knock cap (29) and the end surface of the mounting cylinder portion (10), but the front end of the knock cap (29) and the outer cam cylinder are shown. It may be provided on the outer periphery of the mounting cylinder portion (10) between the shoulder portions (38) of (5) or provided between the knock cam pressing portion and the knock cam.

Since the knock cap (29) can be attached to the outer cam barrel by fitting it into the mounting barrel portion (10), the knock cam (7) is not pressed during this mounting. When the knock cap (29) is knocked during use, the knock cam pressing portion (30) comes into contact with the rear end of the shaft portion (28) of the knock cam (7), and the knock cam (7) can be moved forward. Rotor as known (6)
The tip of the refill (3) can be made to protrude from the base (2) of the barrel (1) or to be immersed therein through the above.

[0018]

The present invention is configured as described above, and in a writing instrument having a rotating cam mechanism including an outer cam barrel, a rotor and a knock cam, the outer cam barrel is provided with a mounting barrel portion which extends rearward, and the mounting barrel portion is mounted. Since the knock cap is slidably fitted to the cylindrical portion and the knock cam pressing portion facing the rear end of the knock cam is provided in the knock cap, the knock cap is mounted on the outer cam cylinder and is mounted at the time of assembly. Since it is possible to prevent the knock cam from being pushed, there is no risk of damaging the cam surface formed on the knock cam, and the knock cap mounted on the outer cam barrel can be confirmed. It is also possible to eliminate the incompleteness of the operation caused by the insufficiency.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention and a part of a shaft cylinder and a rotary cam mechanism in section.

FIG. 2 is a side view in which a shaft cylinder is half-sectioned.

FIG. 3 is an exploded perspective view of a rotary cam mechanism portion.

FIG. 4 is a perspective view of a rotary cam mechanism portion.

FIG. 5 is a perspective view in which a part of a rotary cam mechanism is shown in section.

FIG. 6 is a perspective view showing another embodiment of the rotary cam mechanism portion.

7 is an enlarged cross-sectional view of a portion of the rotary cam mechanism shown in FIG. 6 in which an outer cam barrel is fixed to a shaft barrel.

FIG. 8 is a partial half cross-sectional view of an embodiment using a return spring.

[Explanation of symbols]

3 refills 4 springs 5 Outer cam barrel 6 rotor 7 knock cam 10 Mounting tube 29 knock cap 30 Knock cam pressing part 32 Guide ridge 33 enlarged head 35 window 37 Return spring

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B43K 24/08

Claims (7)

(57) [Claims] 1. An outer cam barrel having a cam groove and a cam surface, which is fixed in the shaft barrel, a projection inserted into the cam groove of the outer cam barrel, and a cam which engages with the cam surface of the outer cam barrel. A rotor having a surface, a rotary cam mechanism including a knock cam having a projection inserted into the cam groove of the outer cam barrel and a cam surface engaging with the cam surface of the rotor, and inserted into the barrel. In a writing instrument in which a rear end of the refill is biased rearward by a spring so that the rear end of the refill abuts against the rotor, a mounting cylinder portion extending rearward is formed in the outer cam cylinder, and a knock cap is slid on the mounting cylinder portion. A writing instrument characterized in that a knock cam pressing portion which is fitted as much as possible and which opposes a rear end of the knock cam is provided in the knock cap. 2. The writing instrument according to claim 1, wherein the knock cap is attached to the mounting cylinder portion in a retaining state so as to move back and forth along the mounting cylinder portion and stop at the retracted position. 3. The writing instrument according to claim 2, wherein the mounting cylinder portion has a guide protrusion having an enlarged head portion, and the knock cap has a window portion into which the enlarged head portion is fitted in a state in which it does not come off. 4. The writing instrument according to claim 2, wherein the knock cap is biased toward the retracted position by a return spring. 5. The writing instrument according to claim 4, wherein the return spring is provided between the inner bottom of the knock cap and the end surface of the mounting tubular portion. 6. The writing instrument according to claim 1, wherein the knock cam pressing portion extends so as to project from the inner bottom of the knock cap and faces the shaft portion of the knock cam. 7. The shaft cylinder has an inner step portion, and an inner diameter at the rear of the inner step portion is sequentially enlarged to provide a plurality of enlarged diameter portions, and each of the enlarged diameter portions is formed with an inward projection. The outer projection is provided on the outer periphery of the outer cam cylinder so as to correspond to each of the inner projections, and the outer cam cylinder is fixed in the shaft cylinder by the inner step portion and a plurality of inner projections. Writing instrument.