JPH07290880A - Sharp pencil - Google Patents

Abstract

PURPOSE:To make a number of spring functions and let out a lead by a simple spring structure. CONSTITUTION:A sharp pencil is constituted of a lead tank 2 provided freely slidably in a shaft cylinder 1, a chuck 3 fixed on the apex part of the lead tank 2, a chuck ring 4 fitted movably on the chuck, a sleeve 5 provided between the shaft cylinder 1 and the chuck 3, a spring 6 brought into contact with the sleeve 5 and a part of which is press-bonded on the lead tank 2 and an operating means 13 making the lead tank 2 freely movable in the shaft direction by compressing the spring 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil, and more particularly to a mechanical pencil capable of various kinds of feeding operations by a new spung structure.

[0002]

2. Description of the Related Art Conventionally, as a mechanical pencil of this type, a mechanical pencil having a structure as described in Japanese Utility Model Laid-Open No. 57-111588 has been proposed. That is, as shown in FIG. 6, these conventional devices are writing instruments having a cap 22 mounted on the rear end of the outer cylinder 21 so as to be slidable in the axial direction. Protrusion 23
And a front projection that is fitted to the rear end of the outer cylinder 21, is engaged with the projection 23, regulates the sliding of the projection 23 within the range of the core feed amount, and contacts the peripheral wall of the outer cylinder 21. And a cap engaging cylinder 26 having a rear projection 25. The spring 27 is provided between the top surface of the sleeve 28 and the end surface of the lead tank 29.

[Problems to be Solved by the Invention]

In such a structure, when the chuck 30 and the chuck ring 31 are assembled, the spring 27 is arranged between the top surface of the sleeve 28 and the end surface of the lead tank 29. There is a disadvantage that the slider 32 does not project forward of the specified opening due to a short stroke for pushing out 32. In addition, the spring 27
Since it was inside the sleeve 28, it was difficult to assemble while checking the state of the spring 27 during assembly.

The present invention eliminates the disadvantages of the conventional mechanical pencils described above. The chuck tightening spring and the cushion spring are integrally formed by a new spring system without using a chuck joint for assembling the chuck and the chuck ring. By doing so, it is an object of the present invention to obtain a mechanical pencil which has an extremely simple structure and can sufficiently obtain a stroke for pushing out a slider.

Further, according to the present invention, the yield can be improved because the assembly of the chuck, the chuck ring, and the lead tank can be performed as a mechanism, and these mechanisms can be inserted from the front of the sleeve and the spring can be set from the rear. The purpose is to obtain a mechanical pencil that can be assembled and is extremely easy to assemble.

[0006]

In order to achieve the above object, according to the present invention, a lead tank slidably provided in a shaft cylinder and a chuck fixedly provided at a tip portion of the lead tank. A chuck ring loosely fitted to the chuck, a sleeve provided between the shaft cylinder and the chuck, and an elastic body which is in contact with the sleeve and a part of which is pressure-bonded to the core tank. And a mechanical pencil composed of an operating means for compressing the elastic body to move the lead tank axially.

[0007]

When the lead tank is advanced against the spring by the knocking operation, the chuck is also advanced. In the process of this advance, the chuck ring loosely fitted in the chuck portion comes into contact with the step portion formed on the inner circumference of the tip tool and is removed, and the chuck is released. In this released state, the chuck further advances to push out the slider and feed the lead. When the knock is released, the chuck retracts due to the urging force of the spring,
In this retracting process, the chuck ring again engages with the chuck portion and closes the chuck to hold the lead, thereby enabling writing. If excessive writing pressure is applied during writing, this is transmitted to the spring via the chuck and the lead tank, and the excessive writing pressure is absorbed, preventing breakage of the lead.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a vertical sectional view of an embodiment of a mechanical pencil of the present invention, and FIG. 2 is an explanatory view showing the relationship between a spring and a lead tank. In the figure,
A lead tank 2 for accumulating and feeding a lead is slidably provided in a barrel 1 held by a writer. The chuck 3 is directly press-fitted and fixed to the tip of the lead tank 2. A chuck ring 4 is loosely fitted in the chuck portion 3 a of the chuck 3. Further, a sleeve 5 is provided on the outer periphery of the front portion of the chuck 3, and between the rear end of the sleeve 5 and the step portion 1a formed on the inner periphery of the barrel 1, a small diameter portion is formed in the intermediate portion. A coil spring 6 having the above is wound.

More specifically, this spring 6
Has end turn portions 6a and 6d at the front and rear ends, and the chuck tightening portion 6b having the same diameter is connected to the end turn portion 6a at the front end.
Has a small diameter portion 6c at the rear end of the chuck tightening portion 6b.
Further, a cushion portion 6e having a gradually increasing diameter is formed following the small diameter portion 6c. The front part of the end turn part 6a abuts on the rear end of the sleeve 5, while the end turn part 6d on the other end abuts on the step part 1a of the shaft cylinder 1 and corresponds to the small diameter part 6c. A recess 2a is formed on the outer periphery of the tank 2, and a small diameter portion 6c is positioned in the recess 2a. The core tank 2 may not be provided with the recessed portion 2a, but the core tank 2 may be strongly tightened and positioned directly by the small diameter portion 6c.

Further, the structure of the tip of the mechanical pencil will be described. The male threaded portion of the tip 7 is screwed into the female thread on the inner periphery of the tip of the barrel 1 to form the barrel 1 and the tip 7. Is assembled. A slider 9 is provided inside the tip 7 having an umbrella-shaped packing 8, and a lead protection pipe 10 is integrally attached to the slider 9. An eraser holding member 11 is detachably attached to the rear end of the lead tank 2 together with the eraser 12 so as not to hinder the refilling of the lead tank 2 with a spare lead. Further, an eraser cap 13 is attached to the lead tank 2 so that it can be removed when the eraser is used.

The operation of the mechanical pencil according to the above embodiment will be described below. When the cap 13 provided at the rear end of the lead tank 2 is knocked, the lead tank 2 is advanced against the spring 6, and at the same time, the chuck 3 is also advanced. In the process of this advance, the chuck ring 4 loosely fitted to the chuck portion 3a comes into contact with the stepped portion 7a formed on the inner circumference of the tip tool 7 and is removed, whereby the chuck 3 is opened. In this open state, the chuck 3 further advances to push out the slider 9 and feed the lead through the lead protection pipe 10. When the knock is released, the chuck 3 retracts due to the biasing force of the spring 6, and in the process of this retracting, the chuck ring 4 again engages with the chuck portion 3a to close the chuck 3 and clamp the lead. Writing is possible.

When excessive writing pressure is applied during writing, the chuck 3 is retracted while the lead is held, and the lead tank 2 connected to this chuck 3 is also retracted. That is, since the spring 6 is attached by pressing the small diameter portion 6c into the recess 2a of the lead tank 2 as described above, the cushion portion 6 is retracted as the lead tank 2 moves backward due to excessive writing pressure.
e is compressed and absorbs excessive writing pressure to avoid damage to the lead.

FIG. 3 shows another embodiment of the present invention in which the lead-out operation of the lead is as follows.
Although the knock member at the rear end is exclusively used, in the present embodiment, it is possible to perform the slide type operation and the swing type operation in addition to the rear end knocking operation. In order to enable these operations, an operation window 14 is formed on the side wall of the shaft cylinder 1, and the slide operation member 15 is slid in the axial direction so as to penetrate the operation window 14 and regulate the rear end of the spring 6. Install freely.

Furthermore, in order to enable a swing operation,
Cylindrical weight 1 that hammers into the core tank 2 and acts as a hammer
Fit 6 loosely. That is, the weight 16 is provided at the rear end of the slide operation member 15 so that it can be driven freely, and a stopper 17 is fixed to the inside of the rear end of the barrel 1 so that the weight 16 does not drop off from the rear end when swung. ing. In addition, the stroke of the weight 16 needs to have a sufficient length in consideration of the weight of the weight 16, the strength of the spring 6, and the knock stroke.

The operation of the mechanical pencil according to this embodiment is basically the same as that of the above-mentioned embodiment, but the barrel 1
The lead can be drawn out by sliding the slide operation member 15 provided on the side wall of the. Further, by swinging the weight 16 loosely fitted to the lead tank 2 behind the slide operating member 15 by swinging the mechanical pencil itself back and forth, it is also possible to push out the slide operating member 15 by a hammering action to extend the lead. .

Next, FIGS. 4 and 5 show still another embodiment of the present invention, which differs from the embodiment of FIG. 1 in the shape of the spring and the mounting method. That is,
In the above-described embodiment, the spring 6 is attached by pressure bonding to the core tank 2 by the small diameter portion 6c, but in this embodiment, the rear end 18a of the spring 18 is sharply formed as shown in FIG. The sharp rear end 18a of the lever is installed so as to bite into the lead tank 2. Therefore,
As shown in FIG. 4, the core tank 2 is strongly tightened by the small diameter portion 18b, and the core tank 2 is more firmly held. Therefore, the spring 18 of this embodiment has a substantially uniform diameter, and a recess 2a is formed in the lead tank 2 as shown in FIG. 1 or a step 1a is formed on the inner circumference of the barrel 1. No need, and spring 6
The structure of is also extremely simple.

[0017]

As described above, according to the present invention, the chuck tightening spring and the cushion spring are integrated by a new spring method without using a chuck joint for assembling the chuck and the chuck ring, so that the structure is extremely simple. Moreover, a sufficient stroke for pushing out the slider can be obtained. Further, since the spring is not inside the sleeve upon assembling, the assembling is easy, and the core can be extended by a sliding operation or a swing operation other than the rear end knock.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a mechanical pencil of the present invention.

FIG. 2 is an explanatory view showing a mounting relationship between a lead tank and a spring shown in FIG.

FIG. 3 is a sectional view of another embodiment of the mechanical pencil of the present invention.

FIG. 4 is a sectional view showing still another embodiment of the present invention.

5 is an explanatory view showing the mounting relationship between the lead tank and the spring of FIG. 4. FIG.

FIG. 6 is a cross-sectional view showing a conventional mechanical pencil.

[Explanation of symbols] 1 shaft cylinder 2 core tank 3 chuck 4 chuck ring 5 sleeve 6 spring (elastic body) 7 tip tool 8 packing 9 slider 10 core protection pipe 11 eraser holding member 12 eraser 13 eraser cap (operating means) 14 operation Window 15 Slide operation member (operation means) 16 Weight (operation means) 17 Stopper 18 Spring

Claims (7)

[Claims] 1. A lead tank slidably provided in a barrel, a chuck fixedly mounted on the tip of the lead tank, a chuck ring loosely fitted to the chuck, the barrel and the chuck. A sleeve provided between the sleeve and an elastic body that is in contact with the sleeve and a part of which is crimped to the core tank, and the elastic body is compressed to axially move the core tank. A mechanical pencil characterized by comprising: 2. The mechanical pencil according to claim 1, wherein the elastic body is a coil spring, and a small diameter portion of a portion separated from both ends is crimped to the lead tank. 3. The mechanical pencil according to claim 2, wherein a ring-shaped recess is formed on the outer periphery of the lead tank corresponding to the small diameter portion of the coil spring. 4. The mechanical pencil according to claim 1, wherein the elastic body is a coil spring, and a rear end of the elastic body is embedded in the outer wall portion of the lead tank and is pressure-bonded thereto. 5. The operating means is a knocking means provided at the rear end of the lead tank, 1, 2, 3 or 4.
The described mechanical pencil. 6. The mechanical pencil according to claim 1, wherein the operating means is a slide operating means which penetrates a guide groove formed in a side wall of the barrel and contacts the rear end of the spring. 7. The mechanical pencil according to claim 6, wherein the operating means is a swing weight loosely fitted in the lead tank so as to come into contact with the rear end of the slide operating means.