JP2020090039A - Retractable writing instrument - Google Patents

Abstract

To prevent impairing of operativity of a holder caused by adhesion of a foreign matter.SOLUTION: A retractable writing instrument includes a mechanical pencil unit 1 which advances a holder 20 relative to a lead core x inserted to a holder 20 by a force component in a radial direction applied to the holder 20 projecting from the front end opening of a holding cylinder 10 and relative to the holding cylinder 10, and advances the mechanical pencil unit 1 with a predetermined operation and projects it from the front end opening of a shaft cylinder a1. The retractable writing instrument is provided with a large-diameter part 11a enlarging its diameter in a rear direction on a front end side of the outer periphery of the holding cylinder 10. The large-diameter part 11a is brought into slide contact with a pointed inner wall surface of the shaft cylinder a1 while advancing the mechanical pencil unit 1, and a contact part 11b between the holder 20 and the front end opening of the holding cylinder 10 secures a space s between the contact part and an inner wall surface of the shaft cylinder a1.SELECTED DRAWING: Figure 4

Description

The present invention relates to a retractable writing instrument including a mechanical pencil unit.

Conventionally, in relation to this type of invention, for example, in Patent Document 1, a holding cylinder and a front opening of the holding cylinder are inserted to project forward from the front end of the holding cylinder and to be able to move forward and backward with respect to the holding cylinder. A supported holder, a lead core feeding mechanism that feeds the lead core inserted through the holder forward, and a movement direction change that advances this holder relative to the holding cylinder and the lead core by the radial force applied to the holder from the lead core. And a mechanical pencil unit with a mechanism. If the mechanical pencil unit is housed in the barrel, the retractable writing instrument can be easily constructed.
According to this retractable writing instrument, the mechanical pencil unit is moved forward by a predetermined operation, and when the holder at the front end of the mechanical pencil unit is projected from the opening at the front end of the barrel, the pencil core is projected radially from the holder. When the force is applied, the holder moves forward relative to the holding cylinder and the lead core, so that the holder can cover and protect the lead core.

JP, 2017-159579, A

However, according to the above-mentioned conventional technique, the mechanical pencil unit is advanced while foreign matter (for example, ink scattered due to a drop impact or the like, dust, dust, etc.) is attached to the front end side of the inner wall surface of the barrel. Then, when the holder and the holding cylinder are rubbed against the inner wall surface of the front end side of the shaft cylinder, the foreign matter is transferred to the contact portion between the holder and the front end opening of the holding cylinder, and the operability of the holder is impaired. There is a risk of being lost.

In view of such a problem, the present invention has the following configurations.
A mechanical pencil unit for advancing the holder relative to the lead core inserted in the holder by the radial force component applied to the holder protruding from the front end opening of the holding cylinder and the holding cylinder is provided, and the mechanical pencil unit is predetermined. In the retractable writing instrument which is moved forward by the operation to project from the front end opening of the shaft cylinder, a diameter-expanding portion for expanding the diameter rearward is provided on the outer peripheral front end side of the holding cylinder, and during the forward movement of the mechanical pencil unit. , The enlarged diameter portion is brought into sliding contact with the tapered inner wall surface of the shaft cylinder, and a contact portion between the holder and the front end opening of the holding cylinder secures a gap between the inner wall surface of the shaft cylinder. A retractable writing instrument characterized in that

Since the present invention is configured as described above, it is possible to prevent the operability of the holder from being impaired due to the adhesion of foreign matter.

It is an internal structure figure showing an example of a retractable writing instrument concerning the present invention. It is a longitudinal cross-sectional view showing an example of a mechanical pencil unit included in the same retractable writing instrument. It is a longitudinal cross-sectional view showing the action of the lead core feeding mechanism, (a) shows a normal writing state, (b) shows a state where the holder is advanced. The hatching indicates the portion that has moved from the previous state. It is a longitudinal cross-sectional view which sequentially shows the relationship between the mechanical pencil unit which advances, and a shaft cylinder inner wall surface in (a)-(c).

The following features are disclosed in the present embodiment.
A first feature is provided with a lead core inserted into the holder by a radial force component applied to the holder protruding from the front end opening of the holding cylinder and a mechanical pencil unit for advancing the holder relative to the holding cylinder. In a retractable writing instrument in which the mechanical pencil unit is moved forward by a predetermined operation to project from a front end opening of a shaft cylinder, a diameter-expanded portion that expands rearward is provided on the outer peripheral front end side of the holding cylinder, During the forward movement of the pencil unit, the enlarged diameter portion is brought into sliding contact with the tapered inner wall surface of the barrel, and the contact portion between the holder and the front end opening of the holding barrel is the inner wall surface of the barrel. A gap is secured between them (see FIGS. 1 to 4).
According to this configuration, it is possible to prevent foreign matter adhering to the inner wall surface of the shaft cylinder from being transferred to the contact portion by the gap and impairing the operability of the holder.

A second feature is that both the front end portion of the holder and the enlarged diameter portion are brought into sliding contact with the tapered inner wall surface of the barrel to secure the gap more reliably.

As a third feature, in order to allow the enlarged diameter portion to slidably contact the inner surface of the shaft cylinder, the enlarged diameter portion has an inclined surface that gradually increases in diameter rearward, and the inclined surface has a front surface. The rear side is formed with a gentler inclination angle than the rear side (see FIG. 4 ).

As a fourth feature, in order to obtain a specific structure with low frictional resistance, the inclined surface is connected to the first inclined surface located on the front side and the rear end of the first inclined surface, and And a second inclined surface having an inclination angle less than that of the inclined surface, so that at least a part of the second inclined surface slides on the tapered inner wall surface of the barrel while the mechanical pencil unit is moving forward. (See FIG. 4).

<Specific Embodiment>
Next, specific embodiments having the above characteristics will be described in detail with reference to the drawings. In the present specification, the axial direction means the direction in which the center line of the shaft cylinder a1 or the holding cylinder 10 extends. Further, "front" means one side in the axial direction and the direction in which the lead core is paid out. Further, the “rear” means a side opposite to the one side.

In the retractable writing instrument A shown in FIG. 1, the front end writing portion of the refill connected to the advanced piece a2 (or a3) is moved forward from the front end of the barrel a1 by the operation of selectively advancing the plurality of pieces a2, a3. Project to. According to the illustrated example, the refill is the mechanical pencil unit 1 or the ballpoint pen refill 2.
For example, a piece a2 having a clip a6 with an opening/closing function is moved forward against the urging force of the coil spring a4, and the front end writing portion of the mechanical pencil unit 1 (refill) connected to this piece a2 has a barrel a1. When projecting forward from the front end opening, the piece a2 is locked by the locking part a5 provided in the barrel a1, and this protruding state is maintained.
When the clip a6 is knocked in this protruding state, the lead core x is extended from the front end of the mechanical pencil unit 1.
The basic structure shown in, for example, JP-A-2014-198439 can be applied to the multifunctional retractable writing instrument A.

The shaft cylinder a1 is formed of a single or a plurality of cylindrical members into a long cylinder shape, and the inner peripheral surface on the front end side thereof is tapered toward the front side (in other words, a mortar shape, Alternatively, it is formed in a concave curved surface shape. In addition, as another example, the inner wall surface shape on the front end side of the shaft cylinder a1 can be a conical surface shape that is not curved or another tapered shape.

The mechanical pencil unit 1 includes a holding barrel 10, a lead core feeding mechanism M1 supported in the holding barrel 10, a lead tank portion 60 penetratingly inserted into the rear end side of the holding barrel 10, and a lead core x. It is provided with a movement direction conversion mechanism M2 for advancing the holder 20 relative to the lead core x by an applied radial force component, and advances the lead core x by advancing and retracting the lead tank portion 60 in accordance with the knocking operation of the clip a6.

According to the illustrated example, the holding tube 10 is concentrically connected to the first tube portion 11 that is present so as to project the holder 20 forward and the rear end side of the first tube portion 11. The second tubular portion 12 and the third tubular portion 13 concentrically connected to the rear end side of the second tubular portion 12 are integrally formed into a tubular shape. A part or all of the plurality of tubular portions 11, 12, 13 can be made into an integral member.

The lead core feeding mechanism M1 feeds out the lead core x sandwiched by the chuck portion 40 in accordance with the forward/backward movement transmitted from the lead tank portion 60. Further, the lead core feeding mechanism M1 retracts the lead core x and the chuck portion 40 and the like when a backward load stronger than a preset writing pressure is applied to the lead core x held by the chuck portion 40. ..

According to the illustrated example, the lead tank portion 60 is formed by connecting a plurality of tubular members, and the rear end portion is connected to the piece a2 of the retractable writing instrument A. The wick tank portion 60 can also be composed of a single tubular member.

The movement direction conversion mechanism M2 includes the first tubular portion 11, the holder 20, the holder urging member 23, and the like.

According to the illustrated example, the holder 20 is integrally formed of two members, that is, a holder main body 21 and a receiving portion 22 connected to the rear side of the holder main body 21. It is also possible to configure.
The holder 20 is biased rearward by a biasing member 23 (a coil spring in the illustrated example).
On the outer peripheral surface of the holder 20, there is provided an annular cam slope 21a whose diameter gradually increases in the forward direction.

According to the movement direction conversion mechanism M2 having the above-described configuration, in the normal writing state shown in FIG. 3A, the contact portion over the entire circumference is provided between the cam slope 21a of the holder 20 and the front end opening of the holding cylinder 10. 11b is configured.
Further, as shown in FIG. 3B, when the lead core x is strongly pressed against the writing surface p (for example, the paper surface) and an excessive radial force is applied to the lead core x, The cam slope 21a is brought into sliding contact with the front end opening of the holding barrel 10 so that the holder 20 moves forward relative to the lead core x and the holding barrel 10. Therefore, damage to the lead core x can be prevented.

Note that, for example, the structure disclosed in Patent Document 1 can be applied to the basic structure of the lead core feeding mechanism M1 and the movement direction converting mechanism M2.

Further, on the front end side of the outer peripheral surface of the holding cylinder 10, there is provided an annular enlarged diameter portion 11a that gradually increases in diameter rearward. The expanded diameter portion 11a is formed in an inclined surface shape that is gentler on the rear side than on the front side.

More specifically, the expanded diameter portion 11a is connected to the first inclined surface 11a1 that gradually increases in diameter rearward, and the rear side of the first inclined surface 11a1 and the first inclined surface 11a1. And a second inclined surface 11a2 having a gentler inclination angle.
The second inclined surface 11a2 is configured to come into contact with the front end portion of the holding cylinder 10 and the tapered inner wall surface of the shaft cylinder a1. That is, as shown in FIG. 4A, at least a portion of the second inclined surface 11a2 (for example, the second inclined surface 11a2 of the second inclined surface 11a2 is in a state where the front end portion of the holding cylinder 10 is in contact with the inner wall surface of the retaining cylinder 10). The front end or the rear end) is in contact with the rear side of the inner wall surface.

Next, the characteristic effects of the retractable writing instrument A having the above configuration will be described in detail.
When the clip a6 is pushed forward in the initial state in which the mechanical pencil unit 1 is housed in the barrel a1, the piece a2 and the mechanical pencil unit 1 move forward integrally with the clip a6.
At this time, on the front end side of the mechanical pencil unit 1, as shown in FIG. 4A, one or both of the front end portion of the holder 20 and at least a part of the second inclined surface 11a2 is a barrel tube. It contacts the tapered inner wall surface of a1.
By this contact, a gap s is secured between the contact portion 11b of the holder 20 and the holding cylinder 10 and the inner wall surface of the shaft cylinder a1.

The gap s is secured even when the mechanical pencil unit 1 is further advanced, as shown in FIG.
Therefore, the contact portion 11b moves forward of the front end of the shaft cylinder a1 with almost no contact with the inner wall surface of the shaft cylinder a1 or the inner edge of the front end opening a11.

Therefore, even if foreign matter such as ink or dust adheres to the inner peripheral surface on the front end side of the shaft cylinder a1 or the inner edge of the front end opening a11, the foreign matter can be prevented from transferring to the contact portion 11b. Therefore, it is possible to prevent the operation of protecting the lead core by the holder 20 (see FIGS. 3A and 3B) from being hindered by foreign matter.
Moreover, according to a preferred example of the present embodiment, since the expanded diameter portion 11a is formed as a gentle slope by the second inclined surface 11a2, the frictional resistance during the movement is relatively small, and the feeling of operation is small. Is good.

According to the above-mentioned embodiment, although the diameter expansion part 11a was formed from the 1st slope 11a1 and the 2nd slope 11a2, as another preferable example, the 1st slope 11a1 and the 2nd slope It is possible to adopt a mode in which 11a2 is replaced with a continuous convex curved surface-shaped expanded portion. Further, as another example of the enlarged diameter portion 11a, it is possible to adopt a mode in which the diameter is enlarged stepwise toward the rear.

Further, the present invention is not limited to the above-described embodiments, and can be appropriately modified without changing the gist of the present invention.

1: Mechanical pencil unit 10: Holding cylinder 20: Holder 21: Holder main body 11a: Expanded portion 11a1: First inclined surface 11a2: Second inclined surface 11b: Contact portion A: Retractable writing instrument M1: Lead core feeding Mechanism M2: Movement direction conversion mechanism a1: Shaft cylinder s: Gap x: Lead core

Claims (4)

A lead pencil inserted into the holder by a radial force component applied to the holder protruding from the front end opening of the holding barrel and a mechanical pencil unit for advancing the holder relative to the holding barrel are provided, and the mechanical pencil unit is predetermined. In the retractable writing instrument, which is moved forward by the operation of so as to project from the front end opening of the barrel,
An expanded diameter portion that expands rearward is provided on the outer peripheral front end side of the holding cylinder, and the expanded diameter portion is slidably contacted with the tapered inner wall surface of the shaft cylinder while the mechanical pencil unit is moving forward, The retractable writing instrument, wherein a contact portion between the holder and the front end opening of the holding cylinder secures a gap between the holder and the inner wall surface of the barrel. The retractable writing instrument according to claim 1, wherein both the front end portion and the expanded diameter portion of the holder are in sliding contact with the tapered inner wall surface of the barrel. The diameter-increasing portion has an inclined surface that gradually increases in diameter toward the rear, and the inclined surface is formed with a gentler inclination angle on the rear side than on the front side. Item 1. A retractable writing instrument according to item 1 or 2. The inclined surface includes a first inclined surface located on the front side and a second inclined surface that is connected to a rear end of the first inclined surface and has an inclination angle gentler than that of the first inclined surface, 4. The retractable writing instrument according to claim 3, wherein at least a part of the second inclined surface is in sliding contact with the tapered inner wall surface of the barrel while the mechanical pencil unit is moving forward.

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