JPH0628309Y2 - Knock cap structure for knock writing instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Use of the Invention) The present invention relates to a knock cap structure of a knock-type writing instrument.

(Prior art and its problems) In so-called knock-type writing instruments such as mechanical pencils that allow the lead core to be drawn out and ballpoint pens that allow the tip of the writing to appear and disappear, push it inwardly into the rear end of the barrel of the writing instrument body. Many of them have a free knock cap, but these knock caps are pushed inward with respect to the shaft cylinder, so they have a smaller diameter than the inner diameter of the shaft cylinder, or have the same outer diameter as the outer diameter of the shaft cylinder. However, the small diameter part corresponding to the knock stroke must be exposed, and a step is formed between the knock cap and the shaft cylinder, which impairs the appearance and limits the design. There is.

In view of the above circumstances, Japanese Utility Model Publication No. 58-52147 has already proposed a knock cap structure in which a tubular body having a bellows-shaped telescopic tubular portion is attached to the rear end of the barrel of the writing instrument body. In the knock cap structure, the knock cap is composed of a bellows-shaped expandable cylinder part and a knock part formed at the end of the cylinder part. The expandable cylinder part and the knock part conceal the above-mentioned step and the expandable cylinder. It is designed to absorb the operating stroke at the time of knocking by expanding and contracting the part, but since the knock cap is basically made of a soft material, the knock cap is directly fitted to the movable part of the knock type writing instrument. In this case, the deformation of the telescopic cylinder that expands and contracts each time the knocking operation is repeated weakens the engagement of the knocking rod with the knocking rod, and finally the knocking rod comes off.

Therefore, the applicant, as shown in FIG. 2, inserts a head hole 1 into a cap 101 to be fitted to a movable part (not shown) of a knock-type writing instrument.
No. 02 is provided, and the protrusion 104 with the collar 103 that can be fitted and locked in the head hole 102 is provided
Although the above-mentioned problem was not solved by providing it on the bottom surface 106a of No. 6, if the flange 103 of the projection 104 is made larger, it is possible to obtain a certain amount of locking force.
Although it becomes difficult to fit 04 into the head hole 102, and if the collar 103 is made smaller to avoid this, the fitting becomes easier,
On the contrary, this time, there is a contradictory problem that the tubular body 106 is likely to come off.

(Purpose of the Invention) The present invention has been made in view of the above-mentioned problems, and it is possible to reliably assemble a tubular body having a bellows-shaped telescopic tubular portion into a cap fitted to a movable portion of the writing instrument main body side. Moreover, the object of the present invention is to provide a knock cap structure of a knock-type writing instrument which does not come off from the cap even after repeating the knocking operation after the assembling.

(Summary of the Invention) The present invention is a knock cap structure of a knocking type writing instrument in which a bellows-shaped telescopic tube portion is attached to a rear end portion of a shaft tube of a writing instrument body, and the knock cap is fitted to a movable portion of the writing instrument body. A cap to be fitted, a cylindrical body having a bellows-shaped telescopic cylinder part having a protrusion fitting to a head hole formed in the cap, and the hole press-fitted into the hole formed in the protrusion. A bush having a larger diameter is formed, and a retaining projection is formed on the bush, the bush is inserted from the inside of the cylindrical body, and the bush is press-fitted into a hole formed in the projection. It is a thing.

(Embodiment of the Invention) Hereinafter, the present invention will be described in detail based on an embodiment.

1 and 2 show a first embodiment of the present invention, in which 1 is a shaft cylinder of a knock-type writing instrument main body, and inside the shaft cylinder 1, a movable part 2 which is moved back and forth by a knock operation is arranged. Has been done. In the illustrated example, since a mechanical pencil is shown as a knock-type writing instrument, the movable part 2 serves as a lead tank for accommodating a lead core, but in the case of a ballpoint pen, a pressing member capable of pressing and advancing a ballpoint pen refill corresponds to this. Reference numeral 3 denotes a cylindrical cap that is detachably fitted to the movable portion 2, and a head 7a of the cap 3 has a projection 7 to be described later at the center thereof.
Is formed with a head hole 4 into which is fitted. The cap 3 described above is detachably fitted to the movable part 7 to replenish the lead core in the case of a mechanical pencil, but it is not necessary in the case of a ball-point pen, so it is fixed to the movable part 2. Good. Reference numeral 5 is a tubular body having a bellows-shaped telescopic tubular portion 6 having an outer diameter substantially the same as that of the shaft tube 1. The tubular body 5 can be fitted into the head hole 4 at the center of the bottom surface 5a. It has a protrusion 7 to be described in detail. The tubular body 5 is obtained as a molded product of a relatively soft synthetic rubber, synthetic resin or the like, and the bellows-shaped telescopic tubular portion 6 is provided with sufficient elastic force for contraction and extension during knocking operation. . The protrusion 7 has an outer diameter substantially equal to the inner diameter of the head hole 4 of the cap 3, and has a hole 7a in the center.
Reference numeral 8 is a bush having an outer diameter larger than the inner diameter of the hole 7a which is press-fitted into the hole 7a. The bush 8 is formed with an arrow-shaped locking projection 8a and a collar 8b. The knock cap A of the present invention comprises a cap 3, a cylinder 5 and a bush 8. The tip of the cylinder 5 is brought into contact with the rear end of the cylinder 1 and the rear end of the cylinder 1 of the knock type writing instrument main body. Is attached to.

Next, the assembling of the knock cap A in the above-mentioned embodiment and the function and effect will be described. First, the cylindrical body 5 is externally fitted from the rear of the cap 3, and then the projection 7 is fitted into the head hole 4. Next, the bush 8 is inserted from the front inside of the cap 3 and press-fitted into the hole 7a of the projection 7 which is fitted in the head hole 4. When the bush 8 is press-fitted into the hole 7a, since the outer diameter of the bush 8 is larger than the inner diameter of the hole 7a and the locking projection 8a is formed, the projection 7 is pushed outward. That is, the projection 7 is press-fitted into the bush 8 to tightly fit the portion corresponding to the head hole 4, and the other portion is bulged 7b outward to form the cap 3
Since it will be locked to the inner surface of the head wall 3a of the
The fitting and locking of can be made reliable. still,
It is possible to prevent the bush 8 itself from coming off by the action of the locking projection a to the inner surface of the hole 7a.

(Effect of the Invention) As described above, according to the present invention, the bush having a larger outer diameter than the inner diameter of the hole formed in the projection is press-fitted into the projection of the cylindrical body fitted in the head hole of the cap. Then, the projection is pushed outward and the portion corresponding to the head hole 4 is tightly fitted, and the other portions are outwardly bulged and locked to the cap,
Since the projections can be fitted and locked securely, the cylinder does not come off the cap even if the knocking operation is repeated after the attachment. Thus, it is possible to provide a knock cap structure for an excellent knock-type writing instrument that can satisfy the desired external appearance effect and can be put to practical use.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing a conventional example. 1 ... Shaft cylinder, 2 ... Movable part, A ... Knock cap, 3 ... Cap, 4 ... Head hole, 5 ... Cylindrical body, 6 ... Telescopic cylinder part, 7 ... Protrusion, 7a ... Holes, 8 bushes, 8a ... Locking protrusions.

Claims (1)

[Scope of utility model registration request] 1. A knock cap structure of a knock-type writing instrument, wherein a bellows-shaped telescopic tube portion is attached to a rear end of a barrel of a writing instrument body, and the knock cap is a cap fitted to a movable portion of the writing instrument body. A cylindrical body having a bellows-shaped telescopic cylinder part having a protrusion fitted on a head hole formed in the cap and having a diameter larger than the hole press-fitted into the hole formed in the protrusion. A knock cap structure for a knock-type writing instrument, characterized in that it is configured with a bush, and that a locking projection is formed on the bush, the bush is inserted from the inside of the cylindrical body, and is press-fitted into a hole formed in the projection. .