JP2002326493A - Mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure that during writing, the tip of a lead does not find its way into a spot inside the tip of a slider, even when a remaining unused lead is short in a lead feed manipulation, in a mechanical pencil with the slider mounted at the tip of a barrel. SOLUTION: The slider (8) is mounted at the tip of the barrel (1) so that the slider (8) can be transferred in the axial direction and the slider (8) is urged backward by means of a slider spring (12). When the lead is fed, the slider (8) is moved forward by the pushing action of a chuck (3). When the chuck (3) recedes, the slider (8) recedes later than the receding action of the chuck (3) by a delay action means. The slider spring (12) is formed of a superelastic spring as the delay action means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sharp pencil which can be used until the residual core becomes short.

[0002]

2. Description of the Related Art Various sharp pencils are known which can be used even when the length of the core becomes short. FIG.
Reference numeral 2 denotes an example of such a sharp pencil. In the figure, a core feeding mechanism for feeding out a core (2) by knocking operation is provided in a barrel (1). A chuck (3) for gripping the core (2), a clutch (4) fitted around the chuck (3), a chuck spring (5) for urging the chuck backward, and a core connected to the chuck. A tank (6) and the like are included. A slider (8) having a core holder (7) for frictionally holding the core is provided in front of the chuck (3) so as to be movable in the axial direction. The tip protrudes outward from the tip (9) attached to the tip of (1). A slider resistor (11) is provided between the slider (8) and the inner surface (10) of the tip (9) to provide a weak resistance to the movement of the slider.

When the chuck (3) is advanced by pushing a knock button (not shown) provided at the rear end of the barrel (1), the lead can be fed out in a known manner. The phenomenon shown in FIG. 12 occurs. That is, when the remnant core (first core) (2a) becomes shorter and the trailing end is released from gripping of the chuck (3), the chuck returns from the forward position to the retreat position with the clutch (4). Since only the second core (2b) is grasped and returned, the first core (2a) and the second core (2
A gap (A) occurs between b). As a result, when writing pressure is applied to the first core at the time of writing, the tip of the first core slides in the core holding body by this gap (A) and dives into the slider (8), making writing difficult. was there.

[0004]

The problem to be solved by the present invention is as follows.
Even when the residual core (first core) becomes short as described above,
An object of the present invention is to provide a sharp pencil whose tip is prevented from sneaking into a slider during writing.

[0005]

As described above, in order to prevent the remnant core (first core) from penetrating into the slider during writing, after the chuck has retracted while holding the second core, The slider may be retracted while holding the lead with the lead holder, and the rear end of the first lead and the front end of the second lead may be brought into contact with each other so that the above-mentioned gap does not occur between the two leads.

That is, according to the present invention, the core is held in a chuck so that the above-mentioned operation is performed, and the core is extended from the tip of the barrel by knocking operation. In a sharp pencil having a slider movably in the axial direction so as to move forward by being pressed by the chuck when the core is extended, a spring for urging the slider rearward is provided. A sharp pencil is provided, which comprises delay operation means for controlling the movement of the slider so that the slider moves backward after the backward movement of the sharp pencil.

[0007]

1 to 5 show an embodiment of the present invention. For convenience of explanation, parts common to those of the conventional example are denoted by the same reference numerals as shown in FIG. The barrel (1) has a tip (9) at the tip and a core feeding mechanism inside. The lead feeding mechanism includes a chuck (3) for gripping a lead (2), a clutch (4) for releasably fastening the chuck (3), and a lead tank connected to the rear end of the chuck, as is well known. (6) A chuck spring (5) for urging the chuck and the lead tank rearward, and the chuck is advanced by a knock button or a side knock button (not shown) connected to the lead tank to set the lead to the shaft cylinder ( It is configured to be fed out from the tip of the tip (9) of 1).

[0008] A slider (8) is provided on the leading end (9) of the barrel (1) so as to be movable in the axial direction, and a lead holder (7) for frictionally holding a lead in the slider. Are formed. When the chuck advances and unwinds the lead, the slider (8) moves forward by being pressed by the chuck, and moves rearward to a position where it comes into contact with the stopper (13) by a slider spring (12) biasing rearward. Moving. The slider spring
(12) has an elastic force stronger than the frictional force holding the lead by the lead holder (7).

The slider is provided with delay operation means for controlling the movement of the slider so that when the chuck (3) retreats, the slider retreats later than the retraction of the chuck. The delay operation means can be variously configured, and in the embodiment shown in FIGS. 1 to 5, the slider spring (12) for urging the slider is constituted by a super elastic spring to be the delay operation means. .

A super-elastic spring is usually made of a nickel-titanium alloy, and deforms, for example, as shown in the load-deflection curve of the spring shown in FIG. It is known that it changes more slowly in the initial stage of restoration than when it is deformed by adding. Therefore,
When the slider spring (12) is formed of such a spring material, when the chuck (3) retreats from the advanced position, the tip of the chuck and the rear end of the slider do not recede while being in contact with each other. The slider (8) can be moved backward with a time lag behind the backward movement.

The operation of the sharp pencil when the above-mentioned delay operation means is used will be described below. First,
As shown in FIG. 1, when the first wick (2a) is consumed by writing until the tip of the wick (2) is substantially at the same position as the tip of the slider (8), the wick tank (6) is moved in a known manner. By pressing a knock button or the like (not shown) connected to the end, the chuck (3) is moved forward to draw out the first core (2a) (FIG. 2).

In the course of the forward movement, the flange of the clutch (4)
(14) hits the front step (15), but the chuck (3) further advances and presses the slider (8) to move it forward (FIG. 3). At this time, the slider spring (12) is compressed.

When the pressing by the knock button or the like is released, the chuck (3) retreats by the chuck spring (5), is fastened by the clutch (4) on the way, and the second core is moved.
Holding the (2b), the flange (14) of the clutch is a rear step (16)
(FIG. 4). At this time, a gap (B) is generated between the first core (2a) and the second core (2b).

When the slider is moved forward as shown in FIG. 4, the slider (8) is located a distance (C) ahead of the stopper (13). This distance (C) is set to be the same as or slightly larger than the gap (B).

When the slider (8) starts to move backward with a time lag from the backward movement of the chuck (3) by the slider spring (12), the slider (8) is firstly moved by the lead holder (7). It retracts while holding the core (2a), and stops at a position where the rear end of the first core (2a) and the front end of the second core (2b) abut (FIG. 5). In this state, the tip of the first core (2a) protrudes from the tip of the slider (8), so that writing can be performed without any trouble.

FIGS. 7 to 11 show another embodiment, in which when the slider (8) moves forward as a delay operation means, FIG.
A friction engagement portion (17) is provided on the inner surface (10) of the tip (9) of the barrel (1) or the outer periphery of the slider (8) so as to temporarily hold the slider in a frictional manner. That is, according to this embodiment, when the chuck (3) is advanced from the state shown in FIG. 7, the slider (8) is advanced as shown in FIGS. Can be temporarily held.

The slider (8) includes a slider spring (12).
, But is temporarily held by the frictional action of the friction engagement portion (17), so that the backward movement is delayed from the movement of the chuck. That is, as shown in FIG. 10, even if the chuck (3) retreats, it does not retreat immediately but retreats with a time difference. With the slider retracted, the tip of the first core (2a) protrudes from the tip of the slider (8), so that writing can be performed without any trouble.

[0018]

According to the present invention, there is provided the delay operation means for controlling the movement of the slider so that the slider is retracted later than the backward movement of the chuck when the chuck is retracted. Even if the remnant core (first core) becomes short, the slider holds the first core and retreats after the chuck holds the second core and retracts during the operation of feeding the core, so that the tip of the first core Does not sneak into the inside from the tip of the slider, and a sharp pencil that is easy to write is obtained.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention when a tip of a lead is consumed to the same position as a tip of a slider by writing.

FIG. 2 is a half sectional view showing a state where a chuck is advanced from a state shown in FIG. 1;

FIG. 3 is a half sectional view showing a state where the chuck is further advanced from the state shown in FIG. 2;

FIG. 4 is a half sectional view showing a state where the chuck is retracted from the state shown in FIG. 3;

FIG. 5 is a half sectional view showing a state where the slider is retracted from the state shown in FIG. 4;

FIG. 6 is a load-deflection curve diagram of a superelastic spring.

FIG. 7 shows another embodiment of the present invention, and is a half cross-sectional view when the tip of the lead is consumed to the same position as the tip of the slider by writing.

FIG. 8 is a half sectional view of a state where the chuck has been advanced from the state shown in FIG. 7;

FIG. 9 is a half sectional view showing a state where the chuck is further advanced from the state shown in FIG. 8;

10 is a half sectional view of a state where the chuck is retracted from the state shown in FIG. 9;

11 is a half sectional view of a state in which the slider has receded from the state shown in FIG. 10;

FIG. 12 is a half sectional view of a conventional sharp pencil.

[Explanation of symbols]

1 shaft cylinder 2 cores 2a 1st core 2b 2nd core
3 chuck 7-core holder 8 slider 12
Slider spring 17 Friction engagement part

Claims (3)

[Claims] 1. A core feeding mechanism in which a core is gripped by a chuck and is pulled out from the tip of a barrel by a knocking operation. The chuck is pushed by the chuck when the chuck is advanced and the core is fed out. In a sharp pencil provided with a slider movably in the axial direction so as to move forward, a spring for urging the slider backward is provided, and when the chuck retreats, the slider is moved later than the retraction of the chuck. A sharp pencil having a delay operation means for controlling the movement of the slider so as to retreat. 2. A sharp pencil according to claim 1, wherein said spring for urging said slider is formed of a superelastic spring to constitute said delay operation means. 3. The delay operation means is formed on the outer surface of the slider or on the inner surface of the barrel so that the outer periphery of the slider is engaged with the inner surface of the barrel when the slider advances, and the slider is temporarily held frictionally. The sharp pencil according to claim 1, wherein said sharp pencil is a friction engagement portion.