JPH0335587Y2 - - 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 when 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 conventional technology and inventions> A structure that facilitates the tracking of the second and subsequent leads in a sharp pencil and enables 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 backwards and closed, thereby pinching 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 occurs between the first lead and the second lead, which causes the slider to slip when writing. may occur.

It is an object of the present invention to provide a lead feeding mechanism for a sharp pencil that eliminates the drawbacks of the prior art described above and can automatically and reliably center the second and subsequent pencils without the need for a rear end notch.

<Means for solving the problem> 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 that is the main body of the writing instrument. It has a slider that can be retracted by the pressure of the pen that is biased forward by a spring, and a chuck body equipped with a rolling element and a chuck actuating body behind the slider to allow the lead to move forward. Equipped with a chuck mechanism that prevents the slider from retreating, and as the slider moves back forward due to pen pressure, the chuck body also moves forward to expand its mouth, and during that time, the second and subsequent leads are expanded. In a sharp pencil that can be dropped into a chuck body, the chuck body is provided between the chuck body and the chuck actuating body, or in front of the chuck body so as to elastically bias the chuck body backward. A chuck holder is provided that moves in conjunction with the movement in the axial direction, and a sliding tube is provided on the outside of the slider and has an inclined surface that comes into contact with a rolling element arranged in a hole at the rear of the slider, and is elastically biased forward. The inner side of the rolling element is in contact with the front extension of the chuck holder to form a wedge action, and when the slider, which has retreated due to writing, returns to the forward position when the writing pressure is released, Due to the wedge action, the slider advances at least along with the chuck holder (preferably the chuck holder and the chuck body), and the advancement of the chuck holder allows the chuck to move forward and expands the lead clamping opening. This is an automatic lead feed mechanism for sharpening pencils that allows the lead to follow the second and subsequent leads when opened.

<Example> First, a configuration according to a preferred example of the present invention will be described. In FIG. 1, a chuck actuating body 3 that cooperates with a ball chuck mechanism 2 that holds a lead is fixed to a cylindrical body 1 that serves as 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. 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 is further retreated from the normal state, the chuck body 8 closes due to the wedge action of the tapered surface 3a of the chuck actuating body 3 and the rolling element 7, so that the core can be firmly clamped.

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 rear part of the slider 5 has a hole 5a for holding the rolling element 14, a protrusion 5b extending outward at the rear end, and a spring 10 whose rear end is supported by the protrusion 5b. an inclined surface 21 that is biased forward by and comes into contact with the rolling element 14 inwardly;
A sliding cylindrical body 20 having a diameter is provided. Furthermore,
A chuck holder 12 whose base end is fixed to the rear end 8a of the chuck body 8 is disposed outside the chuck body 8. The chuck holder 12 has a cylindrical shape, and has a hole 13 through which the rolling element 7 is rotatably exposed.
have. Further, the tip of the chuck holder 12 forms an extended portion 12a with a reduced diameter and comes into contact with a rolling element 14 disposed at the rear end of the slider 5. That is, the rolling element 1 arranged at the rear of the slider 5
4, the forward-biased sliding cylinder 20, and the chuck holder 12. By creating a wedge action between the slider 5 and the chuck holder 12, the slider 5 is moved backward by writing. When the pen pressure is released and the pen is returned to the forward position, the slider 5 moves forward together with the chuck holder 12 due to the wedge action, and therefore the chuck holder 12 is moved forward at the rear end 8a.
The chuck body 8 fixed to the chuck body 8 is also moved forward, thereby keeping the mouth of the chuck body 8 open to allow the subsequent core to pass through.

It is assumed that not only the structure but also the operation of the present invention has been understood from the above explanation, but a brief explanation will be given below with reference to FIGS. 1 to 5.

In FIG. 1, the slider 5 is in the forward position, and the chuck body 8 is in the retracted position, biting the lead, and is ready for writing. In this state, the front end of the sliding cylinder 20 is in contact with the barrel inner collar 15, and since the rolling elements 14 are floating, they do not have any effect on the front extension 12a of the chuck holder 12.

FIG. 2 shows the writing state. In this state, the slider 5 retreats as the core A wears, but in the direction in which the slider 5 retreats, the sliding cylinder 2
Since the frictional force generated by the wedge action between the slider 0 and the rolling elements 14 is weak enough to not prevent the slider 5 from retreating, the slider 5 can smoothly retreat together with the sliding cylinder 20.

Next, when the tip of the lead pipe 4 is pulled away from the paper surface P in the middle of writing (Fig. 3), the slider 5, which had retreated due to the writing pressure, returns to the forward position due to the elastic force of the spring 9. In the direction in which the slider 5 moves forward, the frictional force generated by the wedge action between the sliding cylinder 20 and the rolling elements 14 is greater than the elastic force of the chuck spring 16 that urges the chuck body 8 backward. 12 and the chuck body 8 connected thereto are moved forward.
As a result, as shown in FIG. 3, the chuck body, which has a self-expanding force, expands to release the core A and allow the second core A' to follow. As shown in the figure, in this state, the front end of the second lead comes into contact with the rear end of the first lead, and tracking is completed.

Thereafter, the advancing slider 5 further advances and stops when it comes into contact with the inner wall of the shaft cylinder, and the sliding cylinder 20 also comes into contact with the inside collar 15 of the shaft cylinder and stops (FIG. 4). At this point, the wedge action that had been occurring up to that point is released, and the chuck body 8 and the chuck holder 12 are moved rearward by the elastic force of the chuck spring 16, so that the chuck body 8 is moved backward as shown in FIG. Close the mouth and hold the core.

FIG. 6 shows a modification of the chuck holder 12 in the above embodiment. That is, in the embodiments of FIGS. 1 to 5, the chuck holder 12
is disposed between the chuck body 8 and the chuck actuating body 3, and is connected to the chuck body 8 at the rear end, whereas in the modification shown in FIG. In addition to the chuck holder 12 having an annular structure that is biased rearward and abuts against the front end of the chuck body 8,
This configuration does not include the spring that urges the rearward direction (that is, the spring 16 of the previous embodiment). The spring stretched between the inner wall of the shaft cylinder and the rear end of the chuck holder 12 (i.e., the spring 16 of the above embodiment) is eliminated, and the other spring 22 and the chuck holder 1 having an annular body structure are used.
2 is configured to produce a similar effect. The operation is the same as that of the previous embodiment, so a detailed explanation will be omitted, but as mentioned above, the structure eliminates the spring (16 in Fig. 1) that urges the chuck body 8 backward. , the forward return of the chuck body 8 is performed by its self-expanding force.

In the modified example shown in FIG. 6, the forward return of the chuck body 8 is made dependent on its self-expanding force, but in order to facilitate this forward return movement, the rear end of the chuck body 8 is A spring 23 with a relatively small elastic force is stretched between the inner wall of the cylinder body 1 and urges the chuck body 8 forward, while the two springs 10 and 10 shown in FIG.
Instead of the spring 22, a single spring 24 having a larger resiliency than the spring 23 may be stretched between the sliding cylinder 20 and the chuck holder 12. In addition, when the tip of the cylinder 1 is screwed into a detachable structure as shown by reference numeral 25 in FIG. 7, when the tip is removed, the chuck holder 1
In order to prevent the chuck holder 2 from falling off, a protrusion 26 may be provided on the outer surface of the front end of the chuck holder 12 so that it can engage with the rolling element 14. Similarly, Figure 1~
In the embodiment shown in FIG. 5, in order to prevent the rolling elements 14 from falling off, the holes 5a of the slider 5 are inclined in the shape of a bowl to prevent the rolling elements 14 from falling inward. It is desirable to do so.

<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 the automatic lead feeding mechanism for a sharp pencil according to the present invention, FIG. 6 is a cross-sectional view showing another embodiment, and FIG.
The figure is a sectional view showing yet another embodiment. DESCRIPTION OF SYMBOLS 1...Shaft cylinder, 2...Chuck mechanism, 3...Chuck operating body, 4...Core pipe, 5...Slider, 7, 14...Rolling element, 8...Chuck body, 1
2...Chuck holding body, 20...Sliding cylinder body.

Claims (1)

[Scope of Claim for Utility Model Registration] 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 core, and is biased forward by a spring. It has a slider that can be retracted by pen pressure,
At the rear of the slider, a chuck mechanism is provided, which has a chuck body equipped with a rolling element and a chuck operating body, and allows the core to move forward but prevents the core from retreating;
As the slider moves back forward due to the pressure of the pen, the chuck body also moves forward, opening its mouth, and during this time, the second and subsequent leads can be dropped into the expanded chuck body. In the pencil pencil, a chuck holder interlocking with the axial movement of the chuck body is disposed between the chuck body and the chuck actuating body or in front of the chuck body so as to elastically urge the chuck body backward. , a sliding cylinder having an inclined surface that comes into contact with a rolling element disposed in a hole at the rear of the slider, and a sliding cylinder that is elastically biased in the front,
The inner side of the rolling element is in contact with the front extension of the chuck holder to form a wedge action, and when the slider, which has retreated due to writing, returns forward due to release of writing pressure, the wedge action The slider moves forward with at least the chuck holder, allowing the chuck to move forward and expanding the lead holding opening to enable automatic lead feeding of the sharp pencil to follow the second and subsequent leads. mechanism.