JP3141170B2 - Mechanical mechanism of mechanical pencil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical mechanism for a mechanical pencil which allows a user to freely adjust a cushion allowance for writing.

[0002]

2. Description of the Related Art Various types of knock type mechanical pencils with a cushion function, in which the core retreats into the writing instrument when the core is subjected to excessive writing pressure, have been proposed in the past, but the core is fixed in accordance with the writing conditions. Until now, there has not been a device equipped with a cushion mechanism that can adjust the pressing position of the lead according to the writing pressure.

[0003]

In a conventional ordinary mechanical pencil, in the writing state in which the lead is knocked and the lead is projected from the tip, the position of the lead is fixed and there is no cushion mechanism even when excessive writing pressure acts. The core was easy to break. In drafting, etc.,
It was especially easy to break when pushing the core longer to draw a long line at a stretch. Also, in the case of the mechanical pencil with the cushion function described above, the size of the cushion with respect to the core cannot be adjusted, so when writing words or when the writing pressure fluctuates drastically due to a change in the material of the paper surface, the core is Repeatedly retreating and protruding frequently in the outer cylinder,
There were issues such as hindering writing.

[0004] The present invention has been made to solve the above problems, and when excessive writing pressure acts on the core,
The cushion can be adjusted to the most suitable cushioning condition (cushion stroke) according to the writing conditions at that time and the hardness, properties, paper quality, etc. of the core so that the core does not break, and when no cushion is required, the retraction of the core is stopped An object of the invention is to obtain a mechanical pencil cushion mechanism that can be used.

[0005]

According to a first aspect of the present invention, there is provided a cushioning mechanism for a mechanical pencil, wherein a meshing portion facing a slant cam of a front outer cylinder is formed in a sleeve.

A cushion mechanism of a mechanical pencil according to a second aspect of the present invention is provided with a meshing portion provided on a front outer cylinder and opposed to a cam for guiding an engagement projection of the sleeve to a predetermined position. is there.

[0007] The cushion mechanism of the mechanical pencil according to a third aspect of the present invention further comprises an eraser feeding mechanism provided at the rear end of the core pipe.

[0008]

According to the cushion mechanism of the mechanical pencil according to the first and second aspects of the present invention, the cushion allowance can be adjusted by a predetermined gap or engagement between the engagement portion and the cam.

The cushion mechanism of the mechanical pencil according to the third aspect of the present invention can further extend and retract the eraser.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; In FIG. 1, reference numeral 1 denotes a front outer cylinder, 2 denotes a rear outer cylinder, which are rotatably connected to the front outer cylinder 1 via a fitting portion 3. A front tool 4 is fixed to the front end of the front outer cylinder 1 via an engaging portion 5.

Reference numeral 6 denotes a lead sending mechanism, on which a lead chuck 7 is slidably mounted in the axial direction. This lead chuck 7
A chuck tightening ring 8 is attached to the end of the lead chuck 7 so as to tighten a chuck portion 7a at the end of the lead chuck 7. Reference numeral 9 denotes an elastic body for fastening the chuck, which is elastically attached between the core pipe 10 and the sleeve 11.

The rear part of the front outer cylinder 1 is shown in FIGS.
As shown in the figure, a cam cylinder 13 having an inclined cam 12 is fixed. Although the cam cylinder 13 is formed separately from the front outer cylinder 1 in this embodiment, it may be formed integrally if necessary. The inclined cam 12 is formed by cutting the cam cylinder 13 into an inclined shape.

The sleeve 11 is slidably and rotatably mounted in the outer cylinders 1 and 2 in the axial direction.
As shown in FIG. 3, it has a meshing portion 11 a protruding from the inclined cam 12 and an engaging protrusion 11 b engaged with the groove 2 a of the rear outer cylinder 2. Therefore, the sleeve 11
By rotating the rear outer cylinder 2, the engagement protrusion 11b
And are integrally rotated via the.

The inclined cam 12 of the cam barrel 13 has a first portion 1 which is separated from the engagement portion 11a of the sleeve 11 in the axial direction.
2a and a second portion 12b close to the engagement portion 11a of the sleeve 11 in the axial direction. The first part 12a and the second part 1 of the inclined cam 12
2b is located around the circumference of the cam cylinder 13 at an interval of about 180 degrees. As shown in FIG. 1, the space (a) between the meshing portion 11a of the sleeve 11 and the first portion 12a of the inclined cam 12 is a cushion allowance for the sleeve 11, and is in the state shown in FIG. Now, maximum cushioning is possible.

When the rear outer cylinder 2 is rotated by 180 degrees with respect to the front outer cylinder 1, the sleeve 11 is also rotated, and the interval (a) is changed from the maximum cushion allowance to the minimum cushion allowance = 0 (inclination) in FIG. (The state in which the engagement portion 11a of the sleeve 11 is in contact with the second portion 12b of the cam 12).

Numeral 14 denotes a cushion elastic body for urging the sleeve 11 forward. Further, the core pipe 10 is mounted in the outer cylinders 1 and 2 so as to be slidable in the axial direction, and an eraser feeding mechanism 15 is disposed at the rear.

[0017] The eraser mechanism 15, as shown in FIG. 1, with fitted detachably to the tubular core 10, detent into the groove 2 b of the rear outer cylinder 2 has been fitted portion 15a
And a joint 15b which is prevented from rotating by the fitting portion 15a;
An eraser guide cylinder 15c rotatably connected to the joint 15b, a spiral groove 15d cut in the inner wall of the eraser guide cylinder 15c, and a movable cylinder holding the eraser 15e engaged with the spiral groove 15d. 15f.
The projection and retraction of the eraser 15e is performed by rotating the rear end of the guide cylinder 15c relatively to the rear outer cylinder 2. Due to this rotation, the moving cylinder 15f moves the spiral groove 1
It moves along 5d, thereby causing the eraser 15e to protrude. If you rotate it in the reverse direction, the eraser 15e
Will retreat.

Next, when the outer cylinders 1 and 2 are further rotated by 180 ° or 180 ° in the opposite direction, the original state shown in FIG. 1 is returned.

In this embodiment, the adjustment of the cushion allowance is performed not at the shrinkage allowance of the elastic body 14 for the cushion but at the distance of the gap (a). As a result, the protection can be achieved, and a certain manufacturing error of the elastic body can be tolerated.

Next, the assembling operation of the mechanical pencil will be described. First, after the elastic body 14 for cushion is wound around the core pipe 10 attached to the core sending mechanism 6,
Outer cylinders 1 and 2 previously set in the front outer cylinder 1 and the rear outer cylinder 2
While considering the positional relationship between the engagement protrusion 11b and the groove 2a.
Assemble from the front. Next, the eraser feeding mechanism 15 is attached to the rear end of the core pipe 10 to complete the assembly. As described above, since the engagement portion 11a for adjusting the cushion allowance is provided on the sleeve 11 that can be dropped into the outer cylinders 1 and 2 and can be easily assembled.

Next, the operation will be described. By knocking the guide cylinder 15c of the eraser feeding mechanism 15, a normal lead sending operation is performed. When the front outer cylinder 1 and the rear outer cylinder 2 are relatively rotated, the sleeve 11 is integrated with the rear outer cylinder 2 via the engagement protrusion 11 b of the sleeve 11.
Rotates. Then, the cushion allowance at the interval (a) is changed from the maximum (a) (the state shown in FIG. 1) to the minimum 0 (the engagement portion 11a comes into contact with the second portion 12b of the inclined cam 12) by the rotation of 180 degrees. State). Therefore, the core 16
When excessive pen pressure acts on the core pipe 10 and the sleeve 1
The whole lead sending mechanism 6 such as 1 retreats into the front outer cylinder 1 and the rear outer cylinder 2 from the maximum (a) to the minimum 0 (in this case, there is no cushioning). Thereby, the core 1
6 can be prevented from being broken due to excessive writing pressure, and the cushion allowance can be freely adjusted according to the writing conditions, the hardness of the core 16, and the like.

An eraser feeding mechanism is mounted from the rear of the rear outer cylinder 2. Therefore, the assembly process can be performed very simply and quickly. Moreover, the number of parts can be reduced.

[0023] Figure 4 shows a second embodiment according to claim 2
FIG. The second embodiment is different from the first embodiment in that a structure for adjusting a cushion allowance, that is, a sleeve 1 is provided.
1 is different from the structure of the front outer cylinder 1 only .
In 4 the mechanical pencil including the rear of the sleeve 11
Although the rear part is omitted, this rear part is used in the first embodiment.
The rear portion of the sleeve 11 has the same configuration as the rear portion of the sleeve 11, and the cushion shown in FIG.
There is an elastic body for cushion corresponding to the elastic body 14 for cushion. The difference in the structure as described above, when the lead delivery mechanism 6 without considering the positional relationship between the engaging projection 11b and the groove 2a can be mounted against the outer tube 1 and 2
Both to allow the engagement projection 11b is and reliably guided naturally into the groove 2a of the rear outer cylinder 2 by a cam 17
You . That is, the sleeve 11 is manufactured on the sleeve 11 itself.
A cushion portion 11c for eliminating the above error and a meshing portion 11a are provided . The engagement portion 11a is
A pair is arranged around the circumference of the probe 11 at an interval of 180 °.
Have been. Each meshing portion 11a has a concave portion 11a '
Inclined portion formed on one of both sides of concave portion 11a '
11aa. In addition, in the meshing part 11a,
It is the inclined portion 11aa that actually adjusts the cushion allowance.
It is.

On the other hand, the inner wall of the front outer cylinder 1
A pair of cams 17 are formed to guide 1b and form a cushion allowance in the gap (a) with the meshing portion 11a. That is, as shown in FIG. 6, a pair of cams 17 are formed in a curved shape so as to guide the engagement protrusions 11b into the passage holes 18, and the passage holes 18 are formed so as to be connected to the grooves 2a of the rear outer cylinder 2. ing.

Next, the operation will be described. When the front outer cylinder 1 and the rear outer cylinder 2 are relatively rotated, the rear outer cylinder 2 is engaged with the engagement protrusion 11b of the sleeve 11 and the groove 2a of the rear outer cylinder 2.
As a result, the sleeve 11 rotates integrally. As a result, as shown by the arrow (b) in FIG.
1aa moves toward the tip of the cam 17. As a result, the interval (a) between the inclined portion 11aa and the tip portion 17a of the cam 17, that is, the cushion allowance is maximum (a) (the state of FIG. 4).
To the minimum 0 (the inclined portion 11aa and the tip 1 as shown in FIG. 5).
7a is in contact). Therefore, core 1
When excessive writing pressure is applied to the core 6, the entire core feeding mechanism 6 such as the core pipe 10 and the sleeve 11 is retracted into the outer cylinders 1 and 2 from the maximum (a) to the minimum 0 (in this case, there is no cushioning). It will be. Accordingly, breakage of the lead 16 due to excessive writing pressure can be prevented, and the cushion allowance can be freely adjusted according to the writing pressure conditions, the hardness of the lead 16, and the like.

In this embodiment, too, the adjustment of the cushion allowance is performed not at the shrinkage allowance of the elastic body 14 for the cushion but at the distance of the gap (a). As a result of not applying a force, the protection can be achieved, and a certain manufacturing error of the elastic body can be tolerated.

Next, the assembling operation of the mechanical pencil will be described. First, after an elastic body 14 for cushion is inserted into the core pipe 10 attached to the core sending mechanism 6, it is assembled from the front of the outer cylinders 1 and 2 set on the front outer cylinder 1 and the rear outer cylinder 2. At this time, the engagement protrusion 11 of the sleeve 11
b is guided by the cam 17 and is reliably guided in the groove 2a of the rear outer cylinder 2, so that assembly is performed extremely easily and reliably. Next, an eraser feeding mechanism 1 is attached to the rear end of the core pipe 10.
5 is mounted to complete the assembly.

[0028]

As described above, according to the first or second aspect of the present invention, the gap between the meshing portion and the cam is adjusted by the rotation of the front and rear outer cylinders, so that the amount of cushion allowance can be extremely reduced. Easy to adjust. According to the third aspect, in addition to the above effects, the eraser can be extended and retracted.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the front outer cylinder of FIG. 1;

FIG. 3 is a plan view of the sleeve of FIG. 1;

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

FIG. 5 is a side sectional view of FIG. 4;

FIG. 6 is a sectional view taken along line AA of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front outer cylinder 2 Rear outer cylinder 6 Core sending mechanism 10 Core pipe 11 Sleeve 11a Meshing part 11b Engagement projection 12 Cam 14 Elastic body 15 Eraser feeding mechanism 17 Cam 18 Passing hole

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B43K 21/16

Claims (3)

(57) [Claims] 1. A front outer cylinder (1) having an inclined cam (12), a rear outer cylinder (2) rotatably connected to the front outer cylinder (1), a front part and a rear part. A sleeve (11) that is slidably housed in the outer cylinders (1) and (2), rotates integrally with the rear outer cylinder (2), and constitutes a part of the core feeding mechanism (6). ), A meshing portion (11a) protruding from the sleeve (11) and opposed to the inclined cam (12) with a predetermined gap therebetween; and the sleeve (11).
Cushioning mechanism for a mechanical pencil, comprising a cushion elastic body (14) for urging the body forward. 2. A front outer cylinder (1) having a cam (17) formed in a guide structure to a passage hole (18), and a rear part rotatably connected to the front outer cylinder (1). The outer cylinder (2), the front outer cylinder (1) and the rear outer cylinder (2) are slidably housed in the outer cylinder (2), and rotate integrally with the rear outer cylinder (2). ) And a state in which the cam (17) faces the sleeve (11).
And a concave portion (11a ') and the concave portion (1).
1a '), an inclined portion (11a) formed on one of both side portions.
a) having a meshing portion (11a), and a sleeve (11).
Formed in the through hole (1) by the cam (17).
8) of the mechanical pencil provided with an engagement projection (11b) for positioning the sleeve (11) at a predetermined position and an elastic body (14) for a cushion for urging the sleeve (11) forward. Cushion mechanism. 3. An eraser feeding mechanism (1) mounted on a core pipe (10) which constitutes a part of a core feeding mechanism (6).
The cushion mechanism for a mechanical pencil according to claim 1 or 2, further comprising (5).