JPH11227384A - Double chuck type mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To project an eraser in a suitable length in response to a wear of the eraser by simply removing an eraser support means as a cassette irrespective of a change in a shape due to use of the eraser. SOLUTION: In the double chuck type mechanical pencil comprising a lead holding front chuck 11 and a lead feeding rear chuck 5, an adapter 3 slidable in an axial direction for locking its rotation with respect to a barrel 1 is fixed to a rear end of a lead tank 4 connected to the chuck 5, and an eraser support means 12 having a support body 13 rotatable with respect to the adapter 3 is detachably provided at a rear part of the adapter 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-chuck mechanical pencil having a front chuck for holding a lead and a rear chuck for feeding the lead, and in particular, an eraser supporting means is detachably provided at the rear of a shaft cylinder. Related to double chuck mechanical pencils.

[0002]

2. Description of the Related Art Conventionally, as a double-chuck type mechanical pencil of this type, various types have been proposed which mainly comprise a front chuck for holding the lead and a rear chuck for feeding the lead, and mainly for the purpose of reducing the loss lead. It had been. However, in this type of double-chuck mechanical pencil, when the core is held between two chucks and one of the chucks is rotated for some reason, the core held by both chucks is twisted and broken. It was something that would.

[0003]

Actually, when the user inadvertently rotates the knock member or the eraser holder connected to the rear chuck through the core tank, or presses the eraser against the paper surface, it is used. When the rotation of the knock member etc. is transmitted to the core tank, the rear chuck also rotates with the core tank, and the front part of the core held by the front chuck and the rear part of the core held by the rear chuck are twisted. Was broken. In such a case,
When the broken core enters between the front chuck and the rear chuck and hinders feeding of the core, or when pushing out the core before centering after breaking, the broken part of the front core and the broken part of the rear core are misaligned. In some cases, it became impossible to pull out the core.

Further, in this type of mechanical pencil, from the viewpoint of its complicated internal structure, it is not possible to secure a sufficient space for the eraser in the rear part of the barrel of the mechanical pencil. Therefore, only a very small thing can actually be attached. This is more remarkable in a double chuck mechanical pencil provided with a chuck for holding the lead and a chuck for feeding the lead in order to reduce the residual lead, that is, the loss lead.

[0005] On the other hand, handwriting can be erased with an eraser because the eraser rubs the writing surface to create the debris,
This is because the core carbon adhered therein is adsorbed and wrapped. Therefore, the eraser is extremely consumed, and in fact is used up quickly.

The present invention has been made in consideration of the complicated structure of a complicated double-chuck mechanical pencil and the characteristics of such an eraser, and the eraser can be used regardless of a change in shape due to the use of the eraser. An object of the present invention is to make it possible to easily remove a supporting means as a cassette and to project an eraser to an appropriate length according to wear of the eraser.

Further, the present invention eliminates the disadvantages of the eraser in terms of structure, and there is no problem in use even if an eraser made of either plastic or rubber is used.
Furthermore, it eliminates the difficulty of directly removing the worn or deteriorated eraser itself when refilling the core, and easily removes the unitized eraser support means without touching the dirty eraser and soiling the fingertip etc. The purpose is to be able to.

Further, according to the present invention, even if the eraser for a mechanical pencil has various sizes, shapes, etc., and there is a variation in production, the eraser can be attached to the rear portion relatively easily. The refill can be easily and accurately refilled, and even when the eraser is used, the rotation of the eraser is prevented from being transmitted to the rear chuck via the core tank, and the rear chuck rotates to rotate the front and rear chucks. An object of the present invention is to prevent the core sandwiched between them from being twisted and broken.

Furthermore, there is usually a disadvantage that a large gap is formed between the shaft cylinder and the core tank due to a difference in diameter of the core cylinder and the core, and the core is caught or the core tank rattles when an eraser is used. According to the present invention, it is an object of the present invention to provide an adapter having a spacer function between a barrel and a core tank to solve such inconvenience.

[0010]

A double chuck mechanical pencil according to the present invention is connected to a rear chuck in a double chuck mechanical pencil having a front chuck for holding a lead and a rear chuck for feeding the lead. An adapter is fixed to the rear end of the core tank, and the adapter is slidable but non-rotatable with respect to the barrel, and an eraser comprising a supporting body rotatable with respect to the adapter at the rear of the adapter. The supporting means is provided detachably.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing a double chuck mechanical pencil according to an embodiment of the present invention. In the figure, a leading tool 2 is screwed to a distal end portion of a shaft cylinder 1. A core tank 4 is slidably provided in the barrel 1. At the rear end of the core tank 4, an adapter 3 having a function of preventing rotation of the barrel 1 as described later is slid in the longitudinal direction. It is movably provided. On the other hand, a rear chuck 5 for feeding the core is press-fitted and fixed to the front end of the core tank 4, and a chuck ring 6 is loosely fitted to the front end of the rear chuck 5.

An elastic cylindrical body 7 is provided in contact with the rear end of the chuck ring 6.
A rear spring 8 is interposed between the core tank 4 and the front end. That is, the elastic tubular body 7 has an inward flange 7a at the front end, and a rear spring 8 as an elastic body is interposed inside the flange 7a. The rear spring 8 urges the core tank 4 and the like rearward with respect to the shaft cylinder 1.

Further, a joint 9 is provided outside the elastic tubular body 7 by a locking structure. In addition, fitting 9
A front spring 10 is interposed between the tip of the small-diameter step portion and the inner wall portion of the leading tool 2 to urge the joint 9 rearward. Further, a front chuck 11 for holding the lead is press-fitted and fixed to the distal end of the small-diameter step portion of the joint 9.

When the front chuck 11 is set on the front tool 2 and the front chuck 11 is advanced, the front chuck 11 holds the lead to such an extent that the lead is prevented from dropping. It is formed to the extent that it moves. A stopper projection 11a is formed on a portion of the front chuck 11 protruding from the tip of the front tool 2. The front chuck 11 has a holding force that withstands writing pressure and holds the lead when the front chuck 11 is retracted.

By the way, the adapter 3 is fixed to the rear portion of the core tank 4 as described above. The adapter 3 has four outer ribs on the outer peripheral portion as is apparent from FIGS. 3a are formed at equal intervals.
The front end of a has a sharp portion 3aa for guiding when the ribs are engaged with the inner rib 1a of the shaft cylinder described later.
Since the sharp portion 3aa functions as a guide when the ribs engage with the inner ribs 1a of the shaft cylinder 1 described later, there is an advantage that the directionality is not considered in assembling. However, the engagement structure between the outer peripheral portion of the adapter 3 and the outer peripheral portion of the barrel 1 is not limited to the ribs described above. What is necessary is just a structure which is impossible. Therefore, for example, an engagement structure in which both the outside of the adapter 3 and the inside of the barrel 1 are formed in a polygonal cross section is included.

On the other hand, an annular projection 3b as a stopper for positioning the support main body 13, which will be described later, is provided at an intermediate portion inside the adapter 3. The inside of the rear end of the adapter 3 has a chamfered portion 3 so that the lead can be easily guided when the lead is refilled.
d is formed. Further, the annular projection 3b formed at the inner middle portion has a slope 3e whose longitudinal section descends rearward so that the core is easily guided.

The outer rib 3a of the adapter 3 (FIG. 3)
Accordingly, since the rotation direction of the adapter 3 is locked with respect to the barrel 1, as shown in FIG. 2, four inner ribs 1a (see FIG. The dotted line portion indicates a state in which the inner rib 1a of the barrel 1 is engaged with the outer rib 3a of the adapter) at equal intervals. In this case, as shown in FIG. 2, the inner rib 1a of the barrel 1 is formed to have a sufficient length in the longitudinal direction in consideration of the knock stroke of the mechanical pencil.

The vertical section of the annular projection 3b corresponds to the slope 3e descending rearward.
A chamfered portion 13c is also formed outside the front end of 3a.
The inner diameter of the support body 13 and the annular projection 3b of the adapter 3
And the inner diameter of the core tank 4 are formed substantially the same so that the core can easily pass through.

Next, a description will be given of the eraser support means 12 which is integrally and detachably provided at the rear portion of the barrel 1. The eraser support means 12 has a cylindrical support body 13 having a leg portion 13 a at a lower portion, and a bottomed eraser jacket 14 provided in an upper portion of the support body 13. In order to cover the eraser attached to the eraser jacket 14, a knock cap 15 is detachably provided between the barrel 1 and the support body 13.

The leg 13a of the support body 13 is rotatably fitted in the rear portion of the adapter 3. That is, although the leg 13a of the support body 13 is rotatable within the adapter 3, the fitting strength of both is erased, and the rubber supporting means does not drop by its own weight. Approximately 1000 g is fitted in the adapter 3.

Hereinafter, the operation of the mechanical pencil according to the embodiment of the present invention will be described. First, when the rear end knock cap 3 is knocked during writing, the front spring 10 is first compressed because the front spring 10 is formed weaker than the rear spring 8. Therefore,
Since the front chuck 11 is advanced and opened, it is possible to receive the lead from behind.

Thereafter, the inclined shoulder of the joint 9 comes into contact with the step formed on the inner side of the front tool 2, and then the rear spring 8
Is compressed, and the rear chuck 5 moves forward together with the core tank 4. During the forward movement of the rear chuck 5, the chuck ring 6 comes into contact with the step formed inside the joint 9, the rear chuck 5 is opened, and the lead advances and is held by its own weight. Thereafter, when the knock is released, the rear chuck 5 returns to the initial position. When further knocked, the rear chuck 5
Is moved forward in the joint 9 while the lead is held, and the lead is sent out.

Further, the core advances in the front chuck 11 and is held by the front chuck 11 and protrudes from the tip. If the core becomes worn during writing, the knock cap 15
When the length of the wick becomes short, a new wick in the wick tank 4 is sent by repeating the knocking operation in the same manner, and the wick worn by the new wick is removed. Extrusion allows further continued use.

When the lead is protruded from the front chuck 11 too long, the rear end knock cap 15 is pressed, the chuck is slightly expanded, and the lead is returned by pressing the lead tip. As a result, the protrusion length of the lead can be adjusted, and breakage of the lead can be prevented. If a mistake is made during writing, the cap 15 may be removed from the barrel 1 and erased while the eraser is protruding from the eraser jacket.

When the eraser is used, a considerable rotational force is applied to the eraser although there are individual differences. On the other hand, the adapter 3 is provided so as to be slidable but not rotatable with respect to the barrel 1. That is, since the adapter 3 is not fixed to the barrel 1, there is some play. For this reason, when the rotational force of the eraser is transmitted to the adapter 3 via the support main body 13, the adapter 3 may be extremely slightly rotated by the amount of play with the barrel 1. As a result, the adapter 3 is connected to the adapter 3. The rear chuck 5 may be rotated via the core tank 4 to break the core.

However, since the support body 13 of the present invention is rotatable with respect to the adapter 3, the rotational force applied to the eraser is not transmitted to the rear chuck 5 connected to the core tank 4 at all. 11
Also, the core held between them does not break due to twisting. In this case, since the adapter 3 also functions as a spacer, there is no inconvenience that the core tank 4 rattles to make it difficult to erase. After use, cap 15
Cover and store the eraser.

Next, a case will be described in which the lead is consumed and a new lead is refilled into the lead tank 4 during writing. In that case,
The leg 13a of the support body 13 is pulled out from the adapter 3 fixed to the rear part of the core tank 4. At that time, the eraser support means 12 has a so-called cassette structure which is unitized as a whole, and the adapter 13 and the leg 13a of the support body 13 are provided.
Is a rotatable fitting structure, so that the cap 15 can be easily pulled out without touching the eraser.
Therefore, the barrel 3 is guided by the guide slopes 3d and 3e of the adapter 3.
The wick can be smoothly refilled into the wick tank 4 via the adapter 3 from the rear opening of the wick.

In the mechanical pencil according to this embodiment, the lead for writing can be fed by the rear end knock. The use of the eraser is performed by removing the knock cap 15, but when the eraser is reduced by abrasion, the eraser is taken out together with the jacket 14 from the support body 13, the split groove 14a of the jacket 14 is expanded, and the eraser is pulled out. Groove 14a when released
Returns to its original position and re-clamps the eraser.

Therefore, the eraser can be attached to the support main body 13 and the eraser support means 12 can be integrally assembled to the mechanical pencil. In addition, when refilling the spare core, if the knock cap 15 is removed and the upper end of the eraser support means 12 is picked and removed, the cassette can be easily removed without touching the eraser and without removing the eraser.

FIG. 5 is a partial longitudinal sectional view showing a modification of the eraser jacket shown in FIG. 1. In this case, the jacket 14 'has a C-shaped cross section without a bottom. The use of the jacket 14 'can reduce the number of parts compared to a mechanism (not shown) for rotating the eraser in accordance with the degree of wear of the eraser. Further, not only can a thicker eraser be used, but also there is an advantage that the eraser can be made longer as compared with the case of using the bottomed eraser jacket 14 of FIG.

That is, since the jacket 14 ′ has no bottom, the jacket 14 ′ is constantly locked at the upper end of the support body 13, and the eraser can be inserted deep into the support body 13. Therefore, if the eraser is worn, the eraser is pulled out together with the jacket and the cut 14'a of the jacket 14'a.
May be expanded to project the eraser by a required length, and then returned to the support body 13.

Next, FIG. 6 shows a modification of the barrel 1 of FIG. 1. A pair of notches 1b facing each other at the rear end of the barrel 1 to facilitate removal of the eraser supporting means 12 are further provided. Is formed. According to such a configuration, when refilling the core into the core tank 4, the support body 13 can be more easily picked with a finger, and there is an advantage that the removal of the eraser support means 12 becomes easier.

In this case, when the knock cap 15 is to be removed, in order to avoid the disadvantage that the support body 13 comes off from the adapter 3 before the knock cap 15 comes off, the knock cap 15 and the support body 13 are connected to each other. Must be weaker than the fitting between the adapter 3 and the support body 13. Specifically, the fitting strength between the knock cap 15 and the support main body 13 is 100 g to 40 g.
0 g, and the fitting strength between the adapter 3 and the support body 13 is 80
It is desirably 0 g to 1000 g. In addition, the fitting strength between the adapter 3 and the core tank 4 is 200
If it is 0 g or more, it goes without saying that reverse fitting with the knock cap 15 or the support main body 13 cannot occur.

Next, FIG. 7 shows the eraser supporting means 1 of FIG.
It is a fragmentary longitudinal cross-sectional view which shows the modification of Example 2. According to this example, the mounting position of the knock cap 15 which is detachably provided on the upper part of the support main body 13 constituting the eraser support means 12 is different from the above embodiments. That is, in the present embodiment, the lower end edge of the knock cap 15 is mounted on the upper surface of the flange 13 a projecting to the side of the support main body 13 projecting from the barrel 1. In FIGS. 1, 5, and 7, the notch 1b may be formed as shown in FIG.

With this configuration, it is possible to easily pull out the eraser supporting means 12 from the barrel 1 by holding the support body 13 protruding from the barrel 1 with fingers without removing the knock cap 15 when refilling the replacement core. I can do it. In this case, there is an advantage that the finger is hooked on the flange 13a of the support body 13 so that it can be more easily pulled out.

[0036]

The present invention is embodied in the form described above, and has various effects as described below.

Even if the eraser support means is formed into a unit or a cassette, and the eraser is used while strongly pressing the eraser against the paper surface, the eraser support body is provided rotatably with respect to the adapter, and is connected to the core tank because it runs idle. Since rotation is not transmitted to the rear chuck, breakage of the core held by the front chuck is prevented.

Further, the eraser is an elastic material, and when the core is replenished, the eraser becomes brittle due to the deterioration with time or becomes worn due to use, and even if the eraser is shortened, it can be removed regardless of a change in the shape of the eraser. It can be easily and smoothly removed integrally as an eraser support means without touching the eraser itself contaminated with carbon.

Further, since the eraser can be protruded by operating the jacket of the eraser support means according to the degree of wear of the eraser, there is little waste of the eraser.

Further, since an adapter having a spacer function is provided between the barrel and the core tank, an excessive force is applied to the eraser when the eraser is used. The core does not enter between the barrel and the core tank.

Further, since the eraser is not directly attached to the adapter, a step for supporting the eraser, that is, a portion having a different inner diameter is not required on the inner periphery of the eraser to prevent the eraser from sinking. The wick does not get caught when refilling the wick.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a double-chuck mechanical pencil according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of only the barrel of FIG. 1;

FIG. 3 is a partial explanatory view showing a state in which an inner rib of the shaft cylinder of FIG. 1 is engaged with an adapter by a dotted line.

FIG. 4 is a transverse sectional view taken along line AA of FIG. 1;

FIG. 5 is a partial vertical sectional view showing a modification of the eraser jacket of FIG. 1;

FIG. 6 is a partial longitudinal sectional view showing a modification of the rear end of the barrel of FIG. 1;

FIG. 7 is a partial longitudinal sectional view showing a modification of the eraser supporting means of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Tip 3 Adapter 4 Core tank 5 Rear chuck 6 Chuck ring 7 Elastic cylindrical body 8 Rear spring 9 Joint 10 Front spring 11 Front chuck 12 Eraser support means 13 Supporting body 14 Eraser jacket 15 Knock cap

Claims (7)

[Claims] 1. A double-chuck mechanical pencil having a front chuck for holding a lead and a rear chuck for feeding the lead, an adapter is fixed to a rear end of a lead tank connected to the rear chuck, and The adapter is slidable but non-rotatable with respect to the barrel, and eraser support means comprising a support body rotatable with respect to the adapter is detachably provided at the rear of the adapter. Chuck type mechanical pencil. 2. The double-chuck mechanical pencil according to claim 1, wherein the eraser supporting means includes an eraser jacket for projecting the eraser in accordance with the consumption of the eraser. 3. The adapter according to claim 1, wherein a positioning stopper is formed on an inner wall of the adapter, and the stopper is formed on a slope having a longitudinal section descending rearward. The double-chuck mechanical pencil described in 1. 4. The double-chuck mechanical pencil according to claim 1, wherein a front end and a rear end of the adapter and legs of the support body are chamfered, respectively. 5. The double-chuck mechanical pencil according to claim 1, wherein a notch is formed at a rear end of the barrel for removing an eraser supporting means. 6. The eraser supporting means further comprises a detachable knock cap at a rear portion of the support body, and the engagement between the knock cap and the support is weaker than the engagement between the adapter and the support body. A double-chuck mechanical pencil according to any one of claims 1 to 5. 7. A removable knock cap is provided on an upper portion of a support main body constituting the eraser support means, and a lower end edge of the knock cap is provided on an upper surface of a flange protruding from a shaft cylinder to a side of the support main body. The double-chuck mechanical pencil according to any one of claims 1 to 6, which is mounted.