JPH0788116B2 - Automatic lead feeding mechanism for the shear pencil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention makes it possible to extend a fixed length of a lead while maintaining a writing posture without requiring a special knocking operation when the lead is worn during writing. The present invention relates to an automatic lead feeding mechanism of a mechanical pencil.

<Prior Art> Many proposals and improvements have been made for a writing instrument capable of performing centering while maintaining a writing posture without performing a special knocking operation. Mechanical pencils of this type can be roughly classified into two types in terms of mechanical and operation.

The first is that the slider and the chuck mechanism are retracted by a predetermined length through the lead, and both are returned to their original positions by releasing the pressing force, but at that time, the slider is temporarily locked in the retracted position. A mechanical pencil for performing centering by returning the chuck mechanism in the meantime and then returning the slider, and is of the type disclosed in Japanese Patent Application Laid-Open No. 57-14099 by the applicant of the present application.

The second is that when the slider and the chuck mechanism retract together through the core, the slider retracts more than the chuck mechanism retracts and the pressing force is released, that is, the writing tip is separated from the paper surface. When returning the slider and the chuck mechanism to their original positions respectively, the return distance of the slider with the core entrainment member inside is made larger than the return distance of the chuck mechanism, and the lead is pulled out from the chuck body by the expansion and forward movement of the slider. (For example, JP-A-60-168699 by the applicant of the present application).

Each of the above types has its own advantages,
The centering operation has also been improved to be more reliable. However, although it is possible to perform the centering while maintaining the writing posture, it is necessary to apply a comparatively large pressing force different from the writing, so that the centering can always be performed while continuously writing. It is not the case that the paper surface is damaged by the pressing operation (knock at the tip) for centering. In addition, as an improvement of this point, an attempt was made to reduce the repulsive force of the related spring so as to perform centering by applying or releasing a pressure equivalent to the writing pressure with an extremely small pressing force. However, in that case, there is a disadvantage in that it is fed out each time a pressing force for writing is applied.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an automatic centering mechanism for mechanical pencils which eliminates the above-mentioned drawbacks and can perform automatic centering operation extremely smoothly.

<Means for Solving Problems> The present invention relates to a tip formed by connecting a core protecting core pipe protruding from the tip of the barrel into a barrel serving as a writing instrument main body, and biasing it backward by a spring. A slide body, a chuck body with a rolling element behind the slider, and a chuck ring that has a chuck ring that allows the lead to move forward but prevents the lead from moving backward. With the return of the chuck body, the chuck body is advanced along with the return, the mouth is expanded, and the second and subsequent cores that follow can be dropped into the expanded chuck body. A release ring that has a locking plate that holds the retreating chuck ring in its retracted position, is coupled to the tip slide body, and releases the locking of the chuck ring by the locking plate at the rear end. A release plate attached to the slider, and between the release plate and the slider is urged rearward by a spring to contact the front end of the chuck ring, and when the chuck ring retracts, tilts with respect to the axis. Is an automatic lead-feeding mechanism for a mechanical pencil having an inclined ring that can keep the slider in the retracted position.

<Embodiment> The present invention will be described in more detail below with reference to an embodiment shown in the drawings. First, a configuration according to a particularly preferred embodiment of the present invention will be described with reference to FIG.

In FIG. 1, a barrel 1 serving as the main body of a writing instrument includes a tapered tip 2 and a front shaft 3a and a rear shaft coupled to the front metal 2.
3b, a ball chuck mechanism 4 having a chuck body 5 for holding a core and a chuck ring 8 cooperating therewith are provided in the barrel 1 and a front metal tip 2
A slider 7 to which a core detent 6 made of an elastic material such as rubber is fixed is provided inside so as to be movable in the axial direction.

At the front of the slider, a tip slide body 10 to which a core pipe 9 is connected mainly for the purpose of protecting the core is provided so as to protrude from the tip of the barrel 1, that is, the tip metal 2 and is biased rearward by a tip spring 11. ing. At the rear end of the tip slide body 10, a release ring 13 which projects rearward along the shape of the inner wall of the barrel and releases the locking force of the locking plate 12 which locks the chuck ring 8 from the outside to the rear position. It has a release plate 14 provided with.

The chuck body 5 of the ball chuck mechanism 4 has a self-expanding force, and a pusher 16 is urged backward by a slider spring 15 and brought into contact with the front end of the chuck body 5 at the front end thereof. Trochanter
The slider 17 is provided so as to be slidable relative to the slider 7.

In the air space formed by the slider 7 and the release plate 14 of the tip slide body 10, as shown in the figure, an inclined ring 19 is provided on the front outside.
And the sliders 18 each having an inclined surface that cooperates with the trochanter 17 are disposed on the inside of the rear side, and the inclined ring 19 is biased rearward by a locking spring 20, which will be described in detail later. On the other hand, the slider 18 is urged forward by the slider spring 15, and 18 and 19 are in contact with each other in a normal state where no writing pressure is applied. Reference numeral 21 is a slider spring that biases the slider 7 forward, and its rear end is locked to the inclined ring 19.

The above is the basic structure of the mechanical pencil according to the present invention. Reference numeral 23 is a chuck spring interposed between the chuck body 5 and a ring 24 connected to the chuck ring 8, and reference numeral 25 is a cushion spring 26. The lead receiving member is urged forward by the lead receiving member, and the lead from a lead receiving portion (not shown) formed behind the lead receiving member is smoothly dropped. Therefore, the chuck ring 8, the ring 24 and the core receiver
The three of 25 are operationally one. Further, reference numeral 29 is a ring attached to the inner surface of the front end of the chuck ring 8 for preventing the balls arranged between the chuck body 5 and the inclined surface of the chuck ring 8 from falling off.
Reference numeral 34 is a ring attached to the inner surface of the front end of the slider 18 and prevents the trochanter 17 disposed at the rear end of the slider from falling off.

Next, the structure of the inclined ring will be described with reference to FIGS. 1 and 2. As shown, the tilt ring 19 is
a and a rear cylindrical portion 19b having a diameter larger than that, and a collar portion 19d having a notch 19c vertically provided in the middle thereof.
Further, a release plate 14, which will be described in detail later, is inserted, and the collar portion 19
A one-turn spring 28 is provided between the d and the protrusion 27 fixed to the inner wall of the tip metal 2, and when the chuck ring 8 is retracted and a gap is formed between the chuck ring 8 and the rear end of the tilt ring, the tilt spring is The tilting ring 19 which is biased rearward by 20 is the one-turn spring 28 described above.
It is designed to be tilted by the existence of.
The one-turn spring 28 has a structure in which only both ends are overlapped as shown in FIG. 3A, and a part of the annular body is deformed as shown in FIG. 3B 28
can be a. In FIG. 2, reference numeral 19e is a step portion that engages with the step portion 7a of the slider 7.

The release plate 14 is a substantially cylindrical structure connected to the rear end of the tip slide body 9 as described above, and the release ring 13 having a tapered rear end is connected to the rear end thereof. The release plate 14 itself is configured to fit in the notch 19c of the inclined ring 19.

Next, the operation of the mechanical pencil of the present invention having the above structure will be described with reference to FIGS.

FIG. 5 shows an initial state in which the lead A projects from the lead pipe 9 by a predetermined length, that is, a state before the writing. In this state, the tip slide body 10 connected to the core pipe has the step 10a.
Is brought into contact with the inner surface step of the tip metal 2, the tip of the slider 7 is brought into contact with the tip slide body 10, the chuck body 5 is attached to the pressing tool 16, and the chuck ring 8 is attached to the inclined ring 19.
Are in contact with each other. The inclined ring 19 is pressed by the front end of the chuck ring 8 and is in a state parallel to the axis, and its step portion 19e is not engaged with the step portion 7a of the slider 7.

From the initial state shown in FIG. 5, when the tip of the lead A is lightly pressed against the paper surface or the like by the normal writing pressure when writing, the chuck body 5 and the chuck ring 8 are moved to the shaft cylinder 1 as shown in FIG.
It retreats against the force of the cushion spring 26 provided at the rear portion, and is locked at the retracted position by the step portion of the locking plate 12. The slider 7 also moves backward together with the core A while holding the core by the core detent 6, and the tip slide body 10 also moves backward accordingly. Here, the tilt ring 19 is released from the pressing force of the chuck ring 8 and is pressed rearward by the force of the tilt spring 20 so that the one-turn spring is wound.
It is inclined according to the shape of 28, and its inner surface step 19e is locked to the step 7a of the slider 7. In this way, the writing is the sixth
It is performed in the state of the figure.

As described above, when the writing is continued and the core A protruding from the core pipe 9 is consumed and the paper surface or the like touches the tip of the core pipe 9, as shown in FIG. 6
The distance 1) in the drawing is retreated, and the tip of the locking plate 12 is pressed and expanded by the release ring 13 to release the engagement between the locking plate 12 and the chuck ring 8.

If the tip of the core pipe 9 is separated from the paper surface,
As shown in the figure, the chuck body 5 and the chuck ring 8 are moved forward while gripping the core by the force of the cushion spring 26 to feed the core of a predetermined length from the core pipe 9, and then the chuck ring 8 is moved to the inclined ring 19. When the rear end is brought into contact with and pressed, the inclined ring 19 returns to a state parallel to the axis line again, and the slider 7 is unlocked.

As shown in FIG. 9, the slider 7 unlocked by the inclined ring 19 moves forward while pushing the tip slide body 10 forward by the force of the slider spring 21 against the force of the tip spring 11 to move the core. The core A is grasped by the detent 6 and pulled out from the chuck body 5. At this time, the slider 7 is moved forward by the wedge action of the trochanter 17 and the slider 18 attached to the rear end of the slider 7 so that the chuck body 5 is moved forward by the force of the chuck spring 23. It follows the forward movement of No. 1 and moves forward to expand with its own expanding force to release the core A. When the core of a predetermined length is fed out in this manner, the chuck body 5 advances and expands substantially at the same time, so that the second and subsequent cores can be smoothly dropped into the chuck body 5.

Then, the slider 7 and the tip slide body 10 further advance by the force of the slider spring 21 until the tip slide body 10 abuts the step portion 10a of the step portion 10a with the inner surface step portion of the tip metal 2, and returns to the initial state of FIG. When the slider 7 moves forward at this time, the slider 18
Is brought into contact with the inclined ring 19 and then pushed back slightly backward.
As a result, the wedge action of the trochanter 17 and the slider 18 is released, and the pusher 16 moves backward while pressing the chuck body 5 backwards against the force of the chuck spring 23 by the force of the slider spring 15. The chuck body 5 is closed again to grip the core A.

If the core does not protrude from the core pipe 9 in the initial state of FIG. 5, the tip slide body 10 is in the state of FIG.
Since there is no gap of a distance 1 between the slider 7 and the slider 7, the tip slide body 10 is retracted by the same distance as the retracted portion of the chuck body 5, so that the chuck ring 8 is locked by the locking plate 12. I can't. Therefore, if the core pipe 9 is separated from the paper surface after being pushed in, the chuck body 5 and the chuck ring 8 immediately move forward, and then the slider 7 locked by the inclined ring 19 moves forward with a delay. The lead is paid out from the lead pipe 9 for a predetermined length.

FIG. 10 shows a modification of the inclined ring, in which the inclined ring 19 shown in FIG. 2 is axially divided into two pieces to form inclined ring pieces 19f and 19g, and the front portion of the inclined ring 19 'is O.
It is tightened with the ring 30. In this modification, when the rear end of the inclined ring 19 'is pressed by the chuck ring 8 (see FIG. 1), the front end is opened against the elasticity of the O-ring 30 and the rear end is released. When it is struck, the elasticity of the O-ring closes the front portion so that the slider 7 can be frictionally engaged. In order to secure the engagement with the slider 7, the slider 7 is provided with the stepped portion 7a as in the above-described embodiment (FIGS. 1 to 8), and the projections engaged with this are provided.
19e may be formed on the inner wall of the front part of the inclined ring 19 '. The so-called automatic centering operation while writing is the same as that of the embodiment shown in FIGS. 2 to 8, and therefore its explanation is omitted.

In the above-described embodiment, the chuck body 5 is moved forward and expanded by following the forward movement of the slider 7, so that the second and subsequent cores can be smoothly dropped into the chuck body 5. The second centering mechanism constituted by the slider 18, the slider spring 15, the pressing tool 16 and the chuck spring 23 for urging the chuck body 5 forward is shown as an example. As a mechanism for smoothly dropping the chuck into the chuck body 5,
As shown in FIG. 11, the second centering mechanism is removed, and instead, a chuck spring for biasing the chuck body 5'to the rear side.
23 'is provided and a pushing body 31 capable of pushing and advancing the chuck body 5'is urged rearward by a pushing body spring 32 to move into the ring 24' or the barrel 1 which is joined to the chuck ring 8 '. A knob (not shown) protruding freely from the rear end or the side surface of the barrel 1 is attached to the lead storage tube 33 connected to the rear portion of the push body 31 and is pushed forward by pushing the knob. The chuck body 5 ′ may be pushed forward by the body 31 to be expanded.

<Effects of the Invention> With the configuration as described above, the mechanical pencil of the present invention does not need to apply a relatively large pressing force different from writing, and the writing pressure itself can be converted into an operation for centering. Since the centering is performed by this, the centering operation can be smoothly and surely performed.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view showing the structure of a mechanical pencil according to the present invention, and FIG. 2 is a perspective view of an inclined ring,
FIG. 3A is a perspective view of a single coil spring, FIG. 3B is a perspective view showing a modified example of the single coil spring, FIG. 4 is a perspective view of a release plate provided with a release ring at the rear end, and FIGS. FIG. 10 is an operation explanatory view of the mechanical pencil shown in FIG. 1, FIG. 10 is a perspective view showing another embodiment of the tilt ring, and FIG. 11 is a partially omitted sectional view showing another embodiment of the present invention. Is. 1 ... Shaft cylinder, 4 ... Chuck mechanism, 5 ... Chuck body, 6 ... Core detent, 7 ... Slider, 8 ... Chuck ring, 10 ...
Tip slide body, 12 ... Locking plate, 13 ... Release ring, 14 ... Release plate, 19 ... Inclined ring, 20 ... Inclined spring, 26 ... Cushion spring.

Claims (1)

[Claims] 1. A cushion spring (2) having a chuck body (5) which allows the lead to move forward but prevents the lead from retracting.
6) is provided with a core detent (6) in front of the chuck mechanism (4) which is urged forward by 6) and movably arranged in the barrel (1), and is urged forward by a slider spring (21). And a slider (7), and a tip slide body (10) urged rearward by a tip spring having a smaller elastic force than the slider spring in front of the slider (7), and
Chuck mechanism (4) that retracts when writing pressure is applied to the core
A locking plate (12) for locking the chuck ring (8) in its retracted position is provided in the shaft cylinder, and the chuck ring (8) is locked by the locking plate (12) by retracting the tip slide body (10).
A release plate (14) having a rear end provided with a release ring (13) for releasing the lock of is attached to the tip slide body, and is biased rearward by an inclination spring (20) to push the chuck ring (8). ), And when the chuck ring retracts, an inclined ring (19) that locks the slider (7) that is inclined with respect to the axis and retracted by writing pressure at the retracted position is provided between the slider and the release plate. Automatic lead feeding mechanism for mechanical pencils installed in.