JPH042119B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a writing instrument that can automatically advance the lead during writing and automatically and smoothly follow the second and subsequent leads. is a sharp pencil that allows continuous writing by opening the previously closed chuck body of the slider, which retreats as the lead wears out, and allowing subsequent leads to fall into the chuck body. It relates to an automatic lead feeding mechanism, and can be used not only as a general sharpening pencil but also as a writing instrument for automatic drafting machines.

<Problems to be Solved by the Prior Art and the Invention> A structure that makes it easy to follow the second and subsequent leads in a sharp pencil and allows automatic centering without the so-called trailing end knocking operation is as follows.
There is one disclosed in Japanese Utility Model Application Publication No. 58-164787 by the applicant of the present application. In this structure, an engaging part is provided at the rear of the slider, and an engaging receiving part is provided at the front part of the chuck body, so that the slider and the chuck body are frictionally engaged when the slider retreats, and when the slider returns to forward movement, the chuck body is It was designed so that it could be carried forward and expanded. However, in this structure, since the outer diameter of the engagement receiving portion of the chuck is different depending on whether the chuck is gripping the lead or not, it is not possible to maintain the above-mentioned engagement state constant all the time. Therefore, there was a problem with the reliability of feeding the second core.

In addition, Japanese Patent Application Laid-Open No. 59-93396 and No. 59-93397 disclose a device that uses the chuck's own weight to expand the chuck.
There is a disclosure in the issue. In this structure, a chuck-activated spring is interposed in front of the chuck, which is always in an expanded state, and when the slider retreats, the chuck is pressed backward to close and clamp the core. . However, as mentioned above, since the chuck's own weight is used to expand the chuck,
It is difficult to reliably open and close the chuck, and the chuck tends to swing out of the center.
Gripping the lead at an angle may cause the lead to break, and in this sense there is still room for improvement.

In addition, the mechanism described in Japanese Patent Application Laid-open No. 58-33500 is
When the slider moves backward, the rear part of the slider is pressed against or engaged with the base of the chuck, and when the slider returns forward, the pressure contact or engagement is maintained as it is, and the chuck is carried forward and expanded.
However, since the expanded state of the chuck cannot be maintained until the slider returns, the passage of the second lead is poor, that is, a gap is created between the first lead and the second lead, which causes the slider to slip when writing. There is a possibility that this may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sharp pencil lead feeding mechanism that eliminates the above-mentioned drawbacks of the prior art and is capable of automatically and reliably centering the second and subsequent pencils without the need for a rear end notch.

<Means for Solving the Problems> The present invention has a core pipe for protecting the lead protruding from the tip of the barrel, and a lead detent that frictionally engages with the lead, in the barrel serving as the main body of the writing instrument. It has a slider that is biased forward by a spring and can be retracted by pressure of the pen. Behind the slider, there is a chuck body equipped with a rolling element and a chuck actuating body to allow the lead to move forward, but the Equipped with a chuck mechanism that prevents the slider from retreating, the chuck body is also moved forward as the slider returns to the forward direction after retreating due to pen pressure, opening its mouth, and during this time, the second and subsequent leads are expanded. In the sharp pencil that can be dropped into the chuck body, the slider has a first engaging portion at the rear end, and a substantially cylindrical shape interlocking with the chuck body is provided between the chuck body and the chuck actuating body. A chuck holder is provided, and the chuck holder engages with the first engaging portion to move the chuck holder forward when the slider that has retreated due to writing returns to the forward position when the writing pressure is released. An automatic lead feeding mechanism for a sharp pencil, which has a second engaging part that extends forward, and allows the chuck body to move forward by advancing the chuck holder, and the lead holding opening to expand, thereby making it possible to follow the second and subsequent leads. It is.

<Example> First, a configuration according to a first example of the present invention will be described. In FIG. 1, a chuck actuating body 3 that cooperates with a ball chuck 2 that clamps a lead is fixed to a cylindrical body 1 which is the main body of a writing instrument. The chuck actuating body 3 has a tapered surface 3a on its inner surface that expands toward the distal end, which is the same as the conventional structure. At the tip of the cylinder 1, a slider 5 with a core pipe 4 mainly for protecting the core is disposed so as to be movable in the axial direction, and inside the slider 5 there is a core return member preferably made of an elastic material such as rubber. A stop 6 is provided. Reference numeral 9 denotes a coil spring for urging the slider 5 forward. An O-ring holder 10 to which an O-ring 11 is attached is integrally provided at the rear end of the slider 5. As shown, O
The top surface of the ring 11 projects outward from the outer retaining surface and is adapted to frictionally engage with a chuck retainer 12, which will be described later. Behind the slider 5, a chuck body 8 having a concave portion for receiving a plurality of rolling elements 7 is disposed inside the chuck operating body 3 so as to be movable in the axial direction. When the chuck body 8 retreats further than the normal state, the chuck body 8
When closed, the core can be firmly held.

The configuration up to now is largely the same as the conventional case. The present invention differs from conventional structures in the following points.

That is, the O-ring 11 is attached to the rear end of the slider 6.
An O-ring holder 10 is integrally provided with an O-ring holder 10 attached to the outer periphery, while a chuck holder 12 whose base end is fixed to the rear end 8a of the chuck 8 is disposed outside the chuck 8. ing. The chuck holder 12 has a cylindrical shape and has a hole 13 through which the rolling element 7 is rotatably exposed. Furthermore, a protrusion 14 that can be engaged with an O-ring 11 provided at the rear end of the slider 5 is integrally formed on the inner surface of the tip of the chuck holder 12. That is, while an O-ring 11 is provided at the rear end of the slider 5, a chuck holder 12 having a protrusion 14 that can be engaged with the O-ring 11 is fixed to the chuck body 8, and after the slider 5 is retreated. When the chuck body 8 returns to the forward position again, the chuck body 8 is moved forward by the engagement between the O-ring 11 and the protrusion 14, thereby keeping the mouth of the chuck body 8 open.

It is assumed that the structure and operation of the present invention are understood from the above explanation, but the operation will be briefly explained with reference to FIGS. 1 to 5.

FIG. 1 shows a state in which the chuck is in a predetermined retracted position and grips the lead, ready for writing. In this state, as shown in the figure, the slider 5 is at the most advanced position, and the core pipe 4 protrudes from the tip of the cylinder 1.
In the figure, A1 indicates the first lead, and A2 indicates the subsequent second lead.

FIG. 2 shows the writing state. When writing is performed using the writing instrument in the state shown in FIG. 1, the lead pipe 4 and slider 5 continue to retreat as the lead wears, and the O-ring 11 rides over the protrusion 14 of the chuck holder 12 as shown. In this state, the mouth of the chuck body 8 remains closed, so there is a space between the first wick A1 and the second wick A2, as shown.

When the continuous writing shown in FIG. 2 is stopped and the tip of the writing instrument is pulled away from the paper surface, the slider 5 attempts to return to its original forward position due to the elastic force of the spring 9, as shown in FIG. 3. At that time, the O-ring 11 engages with the protrusion 14 of the chuck holder 12 while holding the chuck holder 1.
At the same time, the chuck body 8 fixed to the chuck holder 12 also continues to move forward, but the chuck holder 12 comes into contact with a stop member 15 provided on the inner wall of the cylindrical body 1 and stops. Figure 3).
In this state, the wedge action between the rolling element 7 of the chuck body 8 and the inclined surface 3a of the chuck operating body 3 is released, so the mouth of the chuck body 8 is slightly expanded and the core advances as the slider 5 advances. It is allowed. Therefore, the lead A2, which had been stopped inside the chuck body 8, is dropped by its own weight until it comes into contact with the rear end of the first lead A1.

Although the chuck holder 12 contacts the stop member 15 and is prevented from moving further, the slider 5 is forced to continue moving forward due to the elastic force of the spring 9.
The O-ring 11 climbs over the protrusion 14 again, releases the engagement, and moves forward to its original position (FIG. 4). in this case,
The mouth of the chuck body 8 remains open until the O-ring 11 finishes climbing over the protrusion 14. Therefore, as the first lead A1 moves forward, the second lead A2 continues to fall under its own weight and becomes connected to the lead A1.

Next, when the O-ring 11 finishes climbing over the protrusion 14 of the chuck holder 12, the chuck holder 12 is moved back by the action of the spring 16 stretched between the cylinder 1 and the proximal end of the chuck holder 12. For,
The chuck body 8 also retreats, and the wedge action between the rolling elements 7 and the inclined surface 3a of the chuck actuating body 3 acts again, so that the mouth of the chuck body 8 is closed and the core is clamped.

As described above, centering of the first line and centering of the second and subsequent lines can be performed continuously.

6 to 8 show an automatic core feeding mechanism according to a second embodiment of the present invention. In this embodiment, a stepped portion 3b is formed on the inner surface of the chuck actuating body 3 at the front part of the inclined surface 3a.
6, the rolling element 7 of the chuck body 8 is lightly engaged by this stepped portion 3b, and the mouth of the chuck body 8 is kept open. Further, in this embodiment, the chuck holder 12 is not directly fixed to the chuck body 8, unlike the first embodiment (FIGS. 1 to 5), in which the chuck holder 12 is engaged with the proximal end of the chuck body 8. The rolling element 7 is engaged with the rolling element 7 without being
It is indirectly connected to the chuck body 8 via.

In the embodiment shown in FIG. 6, as the lead wears out due to writing, the lead pipe and the slider 5 retreat, and the O-ring 11 at the rear end of the slider 5 comes into contact with the protrusion 14 of the chuck holder 12.
Push 2 backwards. When the chuck holder 12 is pushed backward, the rolling elements 7 run over the stepped portion 3b of the chuck operating body 3 due to the elastic force of the chuck spring 16 and reach the inclined surface 3a, thereby closing the mouth of the chuck body 8. A wedge action occurs, keeping the core in a bitten state (Figure 7). When the slider 5 retreats further due to continuous writing, the O-ring 11 at the rear end of the slider 5 will climb over the protrusion 14, but the chuck holder 12 will remain in the state shown in FIG. Maintained. Next, when you stop continuous writing and release the pen pressure, the slider 5 will move to the spring 9.
At this time, the chuck holder 12 is moved forward due to the engagement between the O-ring 11 and the protrusion 14, which is the same as in the first embodiment. However, in this second embodiment, the chuck holder 12, which is moved forward as the slider 5 moves forward, moves the chuck body 8 forward via the rolling elements 7, and the chuck holder 12 moves forward through the rolling elements 7, thereby removing the rolling elements 7 that were in contact with the inclined surface 3a. is lowered into the stepped portion 3b, and the chuck holder 12 comes into contact with the inner wall of the front end of the chuck operating body 3 and stops (FIG. 8). Thereafter, the slider 5 continues to move forward under the action of the spring 9 and returns to the state shown in FIG.

As described above, in the second embodiment, the chuck holder 12 is provided separately from the chuck body, and the chuck body 8 can be held in the forward expanded position via the rolling elements 7. In the first embodiment, when the chuck body retreats, the core simultaneously retreats (when moving from FIG. 4 to FIG. 5, the second core A2, which was moving forward when the chuck body retreats, is moved backward). There is no need to worry about it being pushed back. That is, although the chuck body 8 is biased rearward under the action of the chuck spring 16, the rolling element 7 is lightly engaged with the stepped portion 3b of the chuck actuating body 3, and no wedge action is imparted to the chuck body 8. Therefore, the mouth of the chuck body 8 remains open, and when the mouth of the chuck body 8 is closed, the mouth of the chuck body 8 is immediately closed as soon as it rides on the stepped portion 3b of the rolling element. It is something that will never go away.

In the first example and the second example above,
The O-ring 11 provided at the rear end of the slider 5 is fixedly held in the groove of the holder 10, and as shown in an enlarged view in FIG. It is also possible to form a structure in which the bottom surface 10b of this groove is inclined, and the engagement force with the chuck holder 12 is varied depending on the position of the O-ring 11. In this case, the portion of the chuck holder 12 that engages with the O-ring 11 may be a flat surface, and there is no need to form a projection or the like. In that case, the chuck spring 16 that biases the chuck body backward may be unnecessary, and a wedge action is created between the chuck body 8, the rolling element 7, and the inclined surface 3a of the chuck actuating body 3 simply by retreating the slider 5 due to the writing pressure. It is also possible to make it occur.

FIG. 10 and FIG. 11 show the first embodiment (the first embodiment).
This shows a modification of the chuck body 8 and the chuck actuating body 3, and shows a slot in the front part of the chuck holder 12, which is connected to the chuck body 8 at the base end. , and has a configuration that can expand radially outward under normal conditions,
A stepped portion 12a is formed on the front outer surface of the chuck body 8 and the chuck holding body 12 to connect the chuck operating body 3.
When the chuck holder 12 slides on the front end protrusion 18 and the stepped portion 12a reaches the protrusion 18, the elastic chuck holder 12 expands. Other configurations and operations are as follows:
Since it can be considered to be the same as the first embodiment, the explanation will be omitted.

With the above configuration, when the chuck body 8 is moved forward, the stepped portion 12a can be engaged with the front end protrusion 18 of the chuck operating body 3, and the expanded state can be maintained until the slider 5 is completely returned. Therefore, the second core can pass through. After the slider 5 returns, the engagement between the chuck holding body 12 and the chuck operating body 3 is released, and the chuck body 8 is moved backward by the chuck spring 16 to clamp the lead again.

<Effects of the Invention> Since the automatic core feeding mechanism of the present invention is configured as described above, it is possible to extremely smoothly follow the second and subsequent cores.

[Brief explanation of drawings]

1 to 5 are cross-sectional views showing the structure and operation of an automatic core feeding mechanism according to a first embodiment of the present invention, and FIG.
8 are cross-sectional views showing the second embodiment, FIG. 9 is a view showing a modification of the first engaging portion provided at the rear end of the slider, and FIGS. 10 and 11 are views showing the present invention. FIG. 3 is a sectional view showing still another embodiment of the invention. 1...Cylinder body, 2...Ball chuck, 3...Chuck operating body, 4...Core pipe, 5...Slider, 7...Rolling element, 8...Chuck body, 9...Spring, 11...O Ring, 12...Chuck holder, 14...Protrusion.

Claims (1)

[Scope of Claims] 1. A writing instrument that has a core pipe for protecting the core protruding from the tip of the barrel within the barrel that serves as the main body of the writing instrument, and a core detent that frictionally engages with the lead, and is biased forward by a spring. It has a slider that can be retracted by pen pressure, and behind the slider, it has a chuck body equipped with a rolling element and a chuck actuating body to allow the lead to move forward but has a chuck mechanism that prevents the lead from retreating. In preparation, as the slider moves back forward due to the pressure of the pen, the chuck body is also moved forward and its mouth is expanded, and during this time, the second and subsequent leads can be dropped into the expanded chuck body. The slider has a first engaging portion at its rear end, and a substantially cylindrical chuck holder is provided between the chuck body and the chuck actuating body to interlock with the chuck body, The chuck holder moves when the slider, which has retreated due to writing, returns forward when the pen pressure is released.
a second engaging portion that engages with the first engaging portion to move the chuck holder forward; and the chuck holder advances as the chuck holder moves forward, and the lead holding opening expands. The automatic lead feeding mechanism of the sharp pencil allows the following lead from the second lead onward. 2. The automatic core feeding mechanism according to claim 1, wherein the first engaging portion provided at the rear end of the slider is a rubber O-ring. 3 The O-ring is the O-ring provided at the rear end of the slider.
The automatic core feeding mechanism according to claim 2, wherein the automatic core feeding mechanism is movably disposed in the inclined groove of the ring holder. 4. The automatic core feeding mechanism according to claim 1, wherein the rear end of the chuck holder is connected to the rear end of the chuck body. 5. The automatic core feeding mechanism according to claim 1, wherein the chuck holder is indirectly connected to the chuck body through a rolling element of the chuck body in the vicinity of the rear end. 6. The automatic core feeding mechanism according to claim 1, wherein the second engaging portion of the chuck holder is a projection provided on the inner surface of the front part of the chuck holder.