JP7261032B2 - Mechanical pencil unit and retractable writing instrument - Google Patents

Description

The present invention relates to a mechanical pencil unit constituting a refill for a mechanical pencil, a mechanical pencil, etc., and a retractable writing instrument equipped with the mechanical pencil unit.

Conventionally, in relation to this type of invention, for example, in Patent Document 1, there is disclosed a holding cylinder, a holding cylinder inserted through a front opening of the holding cylinder, projecting forward from the front end of the holding cylinder, and being able to move forward and backward relative to the holding cylinder. A holder that is supported, a lead lead feeding mechanism that advances the lead core that is inserted into the holder, and a movement direction change that moves the holder forward relative to the holding cylinder and the lead core by the radial force applied from the lead core to the holder. A mechanical pencil unit with a mechanism is described. If this mechanical pencil unit is accommodated in the barrel, it is possible to construct a retractable writing instrument.
According to the mechanical pencil unit, when an excessive radial force is applied to the lead core protruding from the holder, the holder advances relative to the holding cylinder and the lead core. can be protected.

JP 2017-159579 A

By the way, in the above conventional technology, the holder is slightly tilted as it moves forward. For this reason, there is a risk that the lead core will be broken or significantly worn along with this inclination.

In view of such problems, the present invention comprises the following configurations.
a holding cylinder, a holder which protrudes from a front end opening of the holding cylinder and is supported so as to advance and retreat, and through which the lead core is inserted; and a lead core feeding mechanism that feeds out the lead core supported and sandwiched by the holding cylinder and inserts it into the holder from the rear side, The inner peripheral surface of the holder is provided with a lead core sliding contact portion that slides on the outer peripheral surface of the lead core at the front end side, and an enlarged diameter portion that is enlarged in diameter behind the lead core sliding contact portion, The mechanical pencil unit according to claim 1, wherein the expanded diameter portion is formed so as to contain only a lead core that tilts as the holder tilts , and the diameter of the expanded portion increases stepwise toward the rear .

Since the present invention is configured as described above, it is possible to prevent the lead core from being damaged due to the inclination accompanying the advance of the holder.

1 is a longitudinal sectional view showing an example of a mechanical pencil unit according to the present invention; FIG. It is a longitudinal cross-sectional view showing an example of a holder, and the two-dot chain line shows the state where the lead core inserted is bent. It is an internal structure diagram showing an example of a writing instrument equipped with the same mechanical pencil unit. It is a vertical cross-sectional view showing the operation of the same mechanical pencil unit, (a) shows the state in which the holder is in the initial position, (b) shows the state in which the holder has advanced to the lead core protection position. In addition, hatching indicates a portion that has moved from the previous state. FIG. 10 is a longitudinal sectional view showing another example of the holder; FIG. 10 is a longitudinal sectional view showing another example of the holder;

The present embodiment discloses the following features.
A first feature is a mechanical pencil unit, comprising a holding barrel, a holder that protrudes from a front end opening of the holding barrel and is supported so as to advance and retreat, and a lead lead is inserted through the holder, and a radial force applied to the holder. a movement direction changing mechanism that tilts while moving the holder forward from an initial position to a lead core protection position, and a lead core that is supported by the holding cylinder and sandwiched between the holding cylinder and feeds out the lead core to move backward relative to the holder; a lead core feeding mechanism that is inserted from the side, and the inner peripheral surface of the holder includes a lead core sliding contact portion that slides on the outer peripheral surface of the lead core on the front end side thereof, and a lead core sliding contact portion that is located behind the lead core sliding contact portion. The enlarged diameter portion is formed so as to include therein a lead core that is inclined along with the inclination of the holder (see FIGS. 1, 2 and 4).

As a second feature, the inner peripheral surface of the enlarged diameter portion is formed so as not to contact the outer peripheral surface of the lead core at the initial position, but to contact the outer peripheral surface of the lead core at the lead core protection position. ing.

As a third feature, the inner peripheral surface of the enlarged diameter portion is formed so as not to contact the outer peripheral surface of the lead core at the initial position and not to contact the outer peripheral surface of the lead core at the lead core protection position. (see FIGS. 2 and 4).

As a fourth feature, the diameter of the enlarged diameter portion is gradually enlarged toward the rear (see FIG. 5).

As a fifth feature, the enlarged diameter portion is continuously enlarged toward the rear (see FIG. 6).

The sixth feature is that the mechanical pencil unit is provided to constitute a retractable writing instrument (see FIG. 3).

<First Embodiment>
Next, specific embodiments having the above characteristics will be described in detail with reference to the drawings. In this specification, the axial direction means the direction in which the center line of the holding cylinder 10 extends. Further, "front" means one side in the axial direction and the direction in which the lead core is drawn out. Also, "rear" means the side opposite to the one side.

A mechanical pencil unit 1 shown in FIG. A movement direction changing mechanism M2 tilts while moving the holder 20 forward from the initial position to the lead core protection position, facing the holding cylinder 10 according to the components, and the lead core x supported and sandwiched in the holding cylinder 10 is delivered to the holder 20. and a lead tank portion 60 connected to the rear end side of the holding cylinder 10 so as to be able to move back and forth. feed out.

Here, the initial position is a position in which an excessive radial force is not applied to the holder 20 (see FIG. 4(a)). At this initial position, the holder 20 keeps the cam slope 21a in contact with the front end opening of the holding cylinder 10 over substantially the entire circumference.
The lead core protection position is a state in which the holder 20 moves forward relative to the holding cylinder 10 due to an excessive radial force component and covers the tip side of the lead core x (see FIG. 4(b)). position.

The holding tube 10 includes a first tube portion 11, a second tube portion 12 concentrically connected to the rear end side of the first tube portion 11, and a rear end side of the second tube portion 12. It is integrally provided with a third cylindrical portion 13 concentrically connected to. These first to third cylindrical portions 11, 12, 13 can be partly or wholly integrated.

Each of the first to third cylindrical portions 11, 12, 13 is made of a hard material such as metal and has a substantially long cylindrical shape.
The first cylindrical portion 11 internally includes a holder 20 that can move forward and backward, and a holder biasing member 23 that biases the holder 20 rearward, thereby forming a movement direction changing mechanism M2.
The second tubular portion 12 and the third tubular portion 13 incorporate a lead breaker 30, a chuck portion 40, and the like to constitute a lead lead feeding mechanism M1.

The holder 20 includes a holder main body 21 having a cam slope 21a, and a cylindrical receiver connected to the rear side of the holder main body 21 to receive the rear end of a holder biasing member 23 (a compression coil spring in the illustrated example). It is integrally formed with the portion 22 and is supported so as to be able to advance and retreat with respect to the holding cylinder 10 .

The holder main body portion 21 is a substantially cylindrical member that is inserted into the first cylindrical portion 11 and protrudes forward from a front opening of the first cylindrical portion 11 . An annular cam slope 21a is provided along the entire periphery of the holder main body 21 so as to be in sliding contact with the front end opening of the first cylindrical portion 11 .

The cam slope 21a is formed in the shape of a conical surface that expands in diameter toward the front. The cam slope 21a advances the holder 20 relative to the holding cylinder 10 by a radial force component applied to the holder 20. As shown in FIG.

Further, on the inner peripheral surface of the holder main body 21, there are a lead core sliding contact portion 21b which is in sliding contact with the outer peripheral surface of the lead core x at the front end side thereof, and an enlarged diameter which is larger behind the lead core sliding contact portion 21b. A diameter portion 21c is formed.

The lead core sliding contact portion 21b is a cylindrical inner peripheral surface, and its inner diameter and length are appropriately set so that it slides on the outer peripheral surface of the lead core x and advances and retreats smoothly.

The inner peripheral surface of the expanded diameter portion 21c does not contact the outer peripheral surface of the lead core x at the initial position (see FIG. 4(a)), and is at the lead core protection position (see FIG. 4(b)). The inner diameter d (see FIG. 2) and the length are appropriately set so as not to come into contact with the outer peripheral surface of the lead core x.

Further, the movement direction conversion mechanism M2 is composed of the first cylindrical portion 11, the cam slope 21a of the holder 20, the holder biasing member 23 that biases the holder 20 backward, and the like. This movement direction changing mechanism M2 is such that when an excessive radial force is applied to the holder 20 via the lead core x, the cam slope 21a moves toward the front end opening of the first cylindrical portion 11 by this radial force component. By pressing and sliding, the holder 20 is advanced from the initial position (see FIG. 4(a)) to a predetermined lead core protection position (see FIG. 4(b)). The holder 20 is slightly tilted as it advances.

Further, the lead lead feeding mechanism M1 includes a lead breaker 30 held on the front end side in the second cylindrical portion 12, a chuck portion 40 that advances and retreats on the rear side of the lead breaker 30, and A clutch ring 41 annularly fitted from the side, a substantially cylindrical clutch receiver 42 that receives the clutch ring 41 from the rear side, a support member 43 that supports the rear end side of the chuck portion 40, and the rear end of the support member 43. A guide tube portion 44 connected to the side thereof to guide the advance and retreat of the lead tank portion 60, and first to third biasing members 51 to 53 are provided.
The lead lead feeding mechanism M1 feeds out the lead core x clamped by the chuck part 40 by forward and backward movement transmitted from the lead tank part 60. As shown in FIG. In addition, the lead feeding mechanism M1 retracts the chuck 40 and the like together with the lead x when a backward biasing force stronger than a preset writing pressure is applied to the lead x clamped by the chuck 40. .

The core breaker 30 is made of an elastic material such as elastomer resin or synthetic rubber and has a substantially cylindrical shape. They are fitted so that they cannot advance or retreat (see FIGS. 1 and 4). The core breaker 30 is loosely pressed against the outer peripheral surface of the lead core x to be inserted.

Note that the basic structure of the lead lead feeding mechanism M1 and the movement direction changing mechanism M2 can be applied to that of Patent Document 1.

Further, the lead tank part 60 is configured in a substantially cylindrical shape with an open front end, and supplies the lead core x from the rear side to the lead lead feeding mechanism M1. The lead tank portion 60 includes a slide cylinder portion 61 engaged with the rear end side of the holding cylinder 10 so as to advance and retreat, and a cylindrical tank body portion 62 connected to the slide cylinder portion 61 and extending rearward. consists of The slide cylinder portion 61 and the tank main body portion 62 can be formed from an integral member.

Then, the mechanical pencil unit 1 having the above configuration is incorporated into a multifunctional retractable writing instrument A, as illustrated in FIG.
In the multi-function retractable writing instrument A, by selectively advancing a plurality of pieces a2 and a3, the front end writing part of the refill connected to the advanced piece a2 (or a3) protrudes forward from the front end of the barrel a1. Let Said refill is, according to the illustrated example, a mechanical pencil unit 1 or a ballpoint pen refill 9 .
For example, a piece a2 having a clip a6 with an opening/closing function is operated to advance against the biasing force of a coil spring a4, and the front end writing portion of a mechanical pencil unit 1 (refill) connected to this piece a2 moves toward the shaft tube a1. When the piece a2 protrudes forward from the front end opening of the shaft tube a1, the piece a2 is locked by the locking portion a5 provided in the shaft tube a1, and this projecting state is maintained.
When the clip a6 is moved forward in this projected state, the lead x is drawn out from the front end of the mechanical pencil unit 1. As shown in FIG.
For this multifunctional retractable writing instrument A, it is possible to apply the basic structure disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-198439.

Next, the characteristic functions and effects of the mechanical pencil unit 1 and the multifunctional retractable writing instrument A configured as described above will be described in detail.

In the normal writing state shown in FIG. 4A, the cam slope 21a of the holder 20 and the front end opening of the holding cylinder 10 are in contact with each other over substantially the entire circumference, and the lead x is inserted from the holding cylinder 10 to the holder 20. is held substantially linearly.

Further, as shown in FIG. 4B, when the lead x is strongly pressed against the writing surface p (for example, a paper surface) and an excessive radial force is applied to the lead x, The inclined cam surface 21 a slides against the front end opening of the holding cylinder 10 , so that the holder 20 moves forward relative to the lead core x and the holding cylinder 10 .
During this forward movement, the holder 20 is slightly tilted as shown in FIG. 4(b). For this reason, the lead core x inserted into the holder 20 is curved and tilted in the front-rear range between the lead core sliding contact portion 21b and the chuck portion 40 .
When the lead core x is tilted as described above, the inner peripheral surface of the core breaker 30 is radially pressed by the lead core x and slightly elastically deformed.

A gap is secured so that the outer peripheral surface of the inclined lead core x does not come into contact with the inner peripheral surface of the enlarged diameter portion 21c in the holder 20. As shown in FIG.
Therefore, the lead core x in the holder 20 can be prevented from coming into contact with the inner peripheral surface of the holder 20, and the lead core x can be prevented from being broken or worn.

According to the above embodiment, as an example, when the holder 20 is in the lead core protecting position, the inclined outer peripheral surface of the lead core x is prevented from coming into contact with the inner peripheral surface of the enlarged diameter portion 21c (Fig. 4(b)), and as another example, when the holder 20 is in the lead core protecting position, the outer peripheral surface of the tilted lead core x is in contact with the inner peripheral surface of the enlarged diameter portion 21c (loose pressure contact). It is also possible to In this other example, the inner diameter d of the expanded diameter portion 21c is appropriately set so as not to break the lead core x due to the contact.

<Second embodiment>
Next, another embodiment of the mechanical pencil unit according to the present invention will be described. Since the embodiments shown below are partially modified from the above-described first embodiment, the modified parts will be mainly described in detail, and the same reference numerals will be used for parts that function in the same way. The redundant detailed description will be omitted.

In the second embodiment, the holder 20 of the mechanical pencil unit 1 having the above configuration is replaced with a holder 20' shown in FIG.

The holder 20' is obtained by replacing the holder body portion 21 of the holder 20 with a holder body portion 21' having an enlarged diameter portion 21d.

The enlarged diameter portion 21d is located on the rear side of the lead core sliding contact portion 21b and is gradually enlarged in diameter toward the rear.
More specifically, as shown in FIG. 5, the enlarged diameter portion 21d includes a plurality of (three in the illustrated example) cylindrical inner peripheral surfaces 21d1 and 21d2 whose diameters are gradually enlarged toward the rear. , 21d3.

According to the mechanical pencil unit equipped with the holder 20' shown in FIG. 5, it is possible to effectively prevent the lead core x from being strongly pressed against the inner peripheral surface of the enlarged diameter portion 21d in the advanced holder 20'. Furthermore, it is possible to more reliably prevent breakage, abrasion, and the like of the lead core x.

<Third embodiment>
In the third embodiment, the holder 20 of the mechanical pencil unit 1 configured as described above is replaced with a holder 20'' shown in FIG.

The holder 20'' is obtained by replacing the holder body portion 21 of the holder 20 with a holder body portion 21'' having an enlarged diameter portion 21e.

As shown in FIG. 6, the diameter-enlarging portion 21e is a conical inner peripheral surface that continuously expands in diameter rearward from the lead-core sliding contact portion 21b on the rear side.

According to the mechanical pencil unit equipped with the holder 20'' shown in FIG. 6, it is possible to effectively prevent the lead core x from being strongly pressed against the inner peripheral surface of the enlarged diameter portion 21e in the advanced holder 20''. Furthermore, it is possible to more reliably prevent breakage, abrasion, and the like of the lead core x.

Although the diameter-enlarging portion 21e shown in FIG. 6 is formed so as to linearly and continuously expand in diameter toward the rear, another example of this diameter-enlarging portion is curved in a trumpet shape toward the rear. It is also possible to adopt a mode in which the diameter is increased while the diameter is increased.

Moreover, the present invention is not limited to the embodiments described above, and can be modified as appropriate without changing the gist of the present invention.

1: Mechanical Pencil Unit 10: Holding Cylinder 11: First Cylinder Part 20, 20′, 20″: Holder 21, 21′, 21″: Holder Body Part 21a: Cam Inclined Surface 22: Receiving Part 23: Holder Biasing Member 21b: lead core sliding contact portion 21c, 21d, 21e: enlarged diameter portion M1: lead core feeding mechanism M2: motion direction changing mechanism x: lead core

Claims (5)

a holding cylinder, a holder which protrudes from a front end opening of the holding cylinder and is supported so as to advance and retreat, and through which the lead core is inserted; and a lead core feeding mechanism that feeds out the lead core supported and sandwiched by the holding cylinder and inserts it into the holder from the rear side,
The inner peripheral surface of the holder is provided with a lead core sliding contact portion that slides on the outer peripheral surface of the lead core at the front end side thereof, and an enlarged diameter portion that is enlarged in diameter behind the lead core sliding contact portion. ,
The mechanical pencil unit according to claim 1, wherein the expanded diameter portion is formed so as to contain only a lead core that tilts as the holder tilts , and the diameter of the expanded portion increases stepwise toward the rear . a holding cylinder, a holder which protrudes from a front end opening of the holding cylinder and is supported so as to advance and retreat, and through which the lead core is inserted; and a lead core feeding mechanism that feeds out the lead core supported and sandwiched by the holding cylinder and inserts it into the holder from the rear side,
The inner peripheral surface of the holder is provided with a lead core sliding contact portion that slides on the outer peripheral surface of the lead core at the front end side thereof, and an enlarged diameter portion that is enlarged in diameter behind the lead core sliding contact portion. ,
The mechanical pencil unit according to claim 1, wherein the expanded diameter portion is formed so as to contain only a lead core that tilts as the holder tilts , and the diameter of the expanded portion increases continuously toward the rear . The inner peripheral surface of the expanded diameter portion is formed so as not to contact the outer peripheral surface of the lead core at the initial position and to contact the outer peripheral surface of the lead core at the lead core protection position. The mechanical pencil unit according to claim 1 or 2 . The inner peripheral surface of the expanded diameter portion is formed so as not to contact the outer peripheral surface of the lead core at the initial position and not to contact the outer peripheral surface of the lead core at the lead core protection position. The mechanical pencil unit according to claim 1 or 2 . A retractable writing instrument comprising the mechanical pencil unit according to any one of claims 1 to 4 .

Images