JP2020116739A - Mechanical pencil unit and retractable writing instrument - Google Patents

Abstract

To ease impact applied on a lead core.SOLUTION: A mechanical pencil unit includes: a chuck part 40 clamping a lead core x; a cylindrical chuck support member 43 supporting the rear end side of the chuck 40 and guiding the lead core x inserted from the rear to the chuck part 40; a holding cylinder 10 incorporating the chuck part 40 and the chuck support member 43 so as to move forward and backward; and a core tank part 60 engaged with the holding cylinder 10 so as to move forward and backward relative to the chuck support member 43 by a predetermined amount, and supplying the lead core to the chuck support member 43 from the rear side. At least part of a range from the chuck support member 43 to a core tank part 60 is provided with a cushioning part which is made of elastic material and into which the lead core is inserted.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mechanical pencil unit constituting a mechanical pencil refill, a mechanical pencil, and the like, 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, a lead core feeding mechanism that feeds a lead core sandwiched by a chuck portion forward by a predetermined operation, and the lead core feeding mechanism, and the chuck portion is provided. A holding cylinder that holds the lead core forward and backward, a lead tank portion connected to the lead core feeding mechanism from the rear side so as to advance and retreat by a predetermined amount, and a front end opening of the holding cylinder. There is described a mechanical pencil unit including a holder that projects forward and backward from a portion and a moving direction conversion mechanism that advances the holder relative to the holding cylinder and the lead core by a radial force applied to the holder from the lead core. ing. Then, the mechanical pencil unit can be housed in the barrel to easily form the retractable writing instrument.
According to this retractable writing instrument, when an excessive backward pressing force is applied to the lead core, the chuck portion can be retracted to prevent the lead core from being broken or damaged.

JP, 2017-159579, A

However, according to the above-mentioned conventional technique, since the chuck portion, the chuck support member, the lead tank portion, and the like can move forward and backward relative to the holding cylinder, the lead core is likely to be damaged or worn due to an impact caused by dropping or the like. In addition, during use, the spare lead core in the lead tank may come into contact with the front and rear members and make an unpleasant impact sound such as a "crown".

In view of such a problem, the present invention has the following configurations.
A chuck portion that holds a lead core; a cylindrical chuck support member that supports the rear end side of the chuck portion and guides a lead core that is inserted from the rear side to the chuck portion; and the chuck portion and the chuck support member. A holding cylinder that is internally movable so as to move forward and backward, and a lead tank portion that engages with the holding cylinder so as to advance and retreat by a predetermined amount in opposition to the chuck support member and that supplies a lead core from the rear side to the chuck support member, A mechanical pencil unit for feeding a lead core forward by an operation of advancing and retracting the lead tank part, wherein the lead core is made of an elastic material in at least a part of a range extending from the chuck support member to the lead tank part. A mechanical pencil unit, characterized in that a first cushioning part for inserting the mechanical pencil is provided.

Since the present invention is configured as described above, it is possible to reduce the impact applied to the lead core from the chuck support member or the core tank portion.

It is a longitudinal cross-sectional view showing an example of a mechanical pencil unit according to the present invention. It is a longitudinal cross-sectional view which sequentially shows the state which advanced the lead tank part about the mechanical pencil unit in (a)-(b). It is a principal part sectional view which shows the rear end side of the mechanical pencil unit. It is an internal structure figure showing an example of a writing instrument provided with the same mechanical pencil unit. It is a longitudinal cross-sectional view showing another example of the mechanical pencil unit according to the present invention. It is a longitudinal cross-sectional view showing another example of the mechanical pencil unit according to the present invention. It is a longitudinal cross-sectional view showing another example of the mechanical pencil unit according to the present invention.

The following features are disclosed in the present embodiment.
A first feature is that a chuck part that holds a lead core, a cylindrical chuck support member that supports a rear end side of the chuck part and guides a lead core inserted from the rear side to the chuck part, and the chuck part. And a holding cylinder in which the chuck support member is present so as to advance and retreat, and a core which engages with the holding cylinder so as to advance and retreat by a predetermined amount relative to the chuck support member and supplies a lead core from the rear side to the chuck support member. A mechanical pencil unit comprising a tank portion, and a lead core being fed forward by an advancing/retreating operation of the lead tank portion, wherein an elastic material is provided in at least a part of a range extending from the chuck support member to the lead tank portion. And a first cushioning portion formed of the same and through which the lead core is inserted (see FIGS. 1 to 3 and 5 to 7).

A second feature is that the first cushioning portion is provided in a cylindrical shape inside the core tank portion away from the rear end of the chuck supporting member rearward (FIGS. 1 to 3 and 5). (See FIG. 7).

As a third feature, the lead tank part includes a slide cylinder part that is connected to the rear end side of the holding cylinder so as to be able to move forward and backward, and a tank main body part that is connected to the slide cylinder part and extends rearward. The first cushioning portion is provided inside the slide tube portion (see FIGS. 1 to 3 ).

As a fourth feature, the first buffer portion is integrally provided on the rear end side of the chuck support member (see FIGS. 5 and 6).

As a fifth feature, the chuck support member includes a support tubular portion that supports the rear end side of the chuck portion, and a guide tubular portion that is connected to the rear side of the support tubular portion and that guides the advancing/retreating of the lead tank portion. The guide tube portion is integrally formed of and and is entirely made of an elastic material, and functions as the first buffer portion (see FIG. 6 ).

A sixth feature is that a second buffer portion made of an elastic material is provided on the rear end side in the core tank portion (see FIGS. 1 and 3 to 7).

A seventh feature is that the retractable writing instrument is configured by including the mechanical pencil unit (see FIG. 4).

<First embodiment>
Next, specific embodiments having the above characteristics will be described in detail with reference to the drawings. In the present specification, the axial direction means the direction in which the center line of the holding cylinder 10 extends. The term "front" means one side of the axial direction in which the lead core is fed. In addition, “rear” means a side opposite to the one side.

The mechanical pencil unit 1 shown in FIG. 1 includes a holding cylinder 10 in which a chuck portion 40, a chuck support member 43, and the like are provided so as to be able to move forward and backward, a holder 20 which projects from a front end opening of the holding cylinder 10 and inserts a lead core x, A movement direction conversion mechanism M2 that moves the holder 20 forward relative to the holding cylinder 10 by a radial force component applied to the holder 20, and a lead core feeding mechanism M1 that feeds the sandwiched lead core x and inserts it into the holder 20 from the rear side. And a lead tank portion 60 that is connected to the rear end side of the holding cylinder 10 and supplies the lead core x from the rear side to the lead core feeding mechanism M1. The lead core x is fed forward from the holder 20 supported by.

The holding cylinder 10 is concentrically connected to the first cylinder portion 11 that constitutes the movement direction conversion mechanism M2 and the rear end side of the first cylinder portion 11 and that constitutes the lead core feeding mechanism M1. It has a tubular portion 12 and a third tubular portion 13. These first to third tubular portions 11, 12 and 13 are each formed of a hard material such as metal into a substantially cylindrical shape. In addition, as another example, it is possible to make a part or all of the plurality of tubular portions 11, 12, 13 into an integral member.

The third tubular portion 13 is formed in an elongated cylindrical shape, and has a rear end thereof with an engaging portion 13a protruding inward in the radial direction. The engaging portion 13a has an inward protruding edge arranged in a space inside a recess 61b of the lead tank portion 60, which will be described later.

The holder 20 is integrally configured of a holder main body 21 having a cam slope 21a and a receiving portion 22 connected to the rear side of the holder main body 21, and is supported in the holding cylinder 10 so as to be movable back and forth. In addition, as another example, the holder main body 21 and the receiving portion 22 can be formed as an integral member.

The movement direction conversion mechanism M2 includes a front end opening of the first tubular portion 11, a cam slope 21a of the holder 20, a holder biasing member 23 that biases the holder 20 rearward, and the like. This movement direction conversion mechanism M2 advances the holder 20 relative to the lead core x and the holding cylinder 10 and the like by the radial force component applied to the holder 20 through the inserted lead core x, and the radial force is applied. When the components are removed, the holder 20 is retracted by the urging force of the holder urging member 23.

The lead core feeding mechanism M1 includes a lead breaker 30 that is held in the holding barrel 10 and is elastically pressure-welded to the outer peripheral surface of the lead core x, and a lead breaker in the holding barrel 10 that is behind the lead breaker 30. The chuck part 40 that holds the core x and can move back and forth, the clutch ring 41 that fits in an annular shape with the chuck part 40, the clutch receiver 42 that receives the clutch ring 41 from its rear side, and the rear end side of the chuck part 40 are provided. A cylindrical chuck support member 43 that supports and guides the lead core x inserted from the rear to the chuck portion 40, and first to third biasing members 51 to 53 are provided.
The lead core feeding mechanism M<b>1 having this configuration feeds the lead core x held by the chuck portion 40 by the forward/backward movement transmitted from the lead tank portion 60. Further, the lead core feeding mechanism M1 is configured such that when the lead core x held by the chuck portion 40 is applied with a biasing force stronger than a preset writing pressure, the lead core x, the chuck portion 40, the chuck support member 43, and the like. Retreat.

The chuck support member 43 is integrally composed of a support tubular portion 43a that supports the rear end side of the chuck portion 40 and a guide tubular portion 43b that is connected to the rear side of the support tubular portion 43a and that guides the lead tank portion 60 back and forth. And is supported so as to advance and retreat relative to the holding cylinder 10.

The basic structure of the lead core feeding mechanism M1 and the movement direction converting mechanism M2 may be the one of Patent Document 1.

The lead tank portion 60 is configured in a substantially tubular shape with an opening at the front end portion, and is arranged at the rear end side of the holding barrel 10 (the third tubular portion 13 according to the illustrated example) so as to face the chuck support member 43 and move back and forth by a predetermined amount. ) Is engaged. The lead tank portion 60 feeds out the existing lead core x forward by its own weight or the like and supplies it to the lead core feeding mechanism M1.
More specifically, the lead tank portion 60 includes a slide cylinder portion 61 that is inserted into the rear end side of the holding cylinder 10 so as to be able to move forward and backward, and a cylindrical shape that is connected to the slide cylinder portion 61 and extends rearward. Tank main body 62, a first cushioning portion 44 installed rearward from the rear end of the chuck support member 43, and a second cushioning portion 45 located on the rear end side of the tank main body 62. doing.

The slide cylinder portion 61 is inserted into the engaging portion 13a of the third cylinder portion 13 and is formed into a substantially cylindrical shape extending in the front-rear direction.
On the outer peripheral portion of the slide cylinder portion 61, a first slide contact portion 61a that slides in contact with the inner peripheral surface of the holding cylinder 10 and a cylindrical recess radially inward from the rear side of the first slide contact portion 61a. A recessed portion 61b is provided. A second slide contact portion 61c is provided on the front end side of the inner peripheral portion of the slide cylinder portion 61.

The length of the recess 61b in the front-rear direction is appropriately set so as to include the maximum forward/backward stroke of the lead tank portion 60.
More specifically, when the lead tank portion 60 is advanced by a knocking operation or the like, as shown in FIGS. 2A and 2B, the interval w1 is narrowed so that the front end of the slide cylinder portion 61 becomes the collar portion 43b1. Abut. Further, when the lead tank portion 60 moves forward, the lead tank portion 60 and the chuck support member 43 move forward integrally (see FIG. 2C), and the lead core x is fed from the lead lead feeding mechanism M1.
The length of the concave portion 61b in the front-rear direction is set so as to include the maximum stroke when the lead tank portion 60 moves back and forth by these operations.

The second sliding contact portion 61c is a cylindrical surface that fits on the outer peripheral surface of the guide cylinder portion 43b of the lead core feeding mechanism M1 on the rear end side, and when the lead tank portion 60 moves forward and backward, Sliding on the outer peripheral surface.

The tank main body portion 62 is formed in a long cylindrical shape capable of accommodating a plurality of lead cores x, and the outer peripheral surface on the front end side thereof is inserted into the slide tubular portion 61 and is detachably fitted thereto.

The first buffer portion 44 is formed of an elastic material (for example, elastomer resin or rubber) into a cylindrical shape into which a lead core can be loosely inserted. The first cushioning portion 44 is fixed at a predetermined position on the front end side of the slide cylinder portion 61 so as not to advance and retract. This fixing means may be, for example, fitting or adhesion.
The distance w2 (see FIGS. 1 and 2) between the first buffer portion 44 and the rear end portion of the guide cylinder portion 43b depends on the distance w1 between the flange portion 43b1 of the guide cylinder portion 43b and the front end portion of the slide cylinder portion 61. Is set appropriately.

For example, if the interval w2 is made smaller than the interval w1, the first buffer portion 44 comes into contact with the rear end of the guide cylinder portion 43b and elastically deforms before the front end of the slide cylinder portion 61 comes into contact with the flange portion 43b1. Therefore, it is possible to mitigate the impact and noise during the knock operation.

The second buffer portion 45 is formed of an elastic material (for example, an elastomer resin or rubber) into a substantially cylindrical shape, and closes the rear end opening of the tank main body portion 62 so that the rear end of the tank main body portion 62 is closed. It is attached to the part.
As shown in FIG. 3, the second cushioning portion 45 includes a fitting portion 45a that is inserted and fitted on the rear end side of the tank body portion 62, and a retractable type that is exposed at the rear side of the fitting portion 45a and will be described later. It is integrally configured with a connecting portion 45b that is detachably fitted to the piece a2 of the writing instrument A.

In addition, according to the illustrated example, the fitting portion 45a is fitted on the inner peripheral surface of the rear end side of the tank main body 62, but as another example, the concavo-convex relationship is reversed, and the outer periphery of the rear end side of the tank main body 62 is reversed. A concave fitting portion (not shown) may be fitted on the surface.
Further, according to the illustrated example, the concave portion provided in the connecting portion 45b is fitted to the convex portion at the tip of the piece a2, but as another example, the concave-convex relationship may be reversed.
Further, according to the illustrated example, the buffer portion 45 is provided on the rear end side of the tank main body portion 62, but as another example, the second buffer portion 45 is previously attached to the piece a2 of the retractable writing instrument A. The tank body 62 may be attached to the second buffer 45.

Next, the characteristic effects of the mechanical pencil unit 1 having the above configuration will be described in detail.
According to the mechanical pencil unit 1 having the above-described configuration, as shown in FIG. 1, when the lead core x is inserted from the chuck portion 40 to the first buffer portion 44, for example, when a strong drop impact is received, The elasticity of the first buffer portion 44 can prevent the rear end side of the lead core x from being broken due to the impact.
In addition, as shown in FIG. 3, when the lead core x is accommodated in the lead tank portion 60, when the lead core x comes into contact with the front and rear first buffer portions 44 and the second buffer portion 45. The impact can be mitigated by the elasticity of the first cushioning portion 44 and the second cushioning portion 45, and further, the unpleasant sound of a "squash" due to the front and rear abutment can be reduced.

Then, the mechanical pencil unit 1 having the above-described configuration is incorporated in the multifunctional retractable writing instrument A as illustrated in FIG.
The multifunctional retractable writing instrument A projects the front end writing portion of the refill connected to the advanced piece a2 (or a3) forward from the front end of the barrel a1 by the operation of selectively advancing the plurality of pieces a2, a3. Let According to the illustrated example, the refill is the mechanical pencil unit 1 or the ballpoint refill 9.
For example, a piece a2 having a clip a6 with an opening/closing function is moved forward against the urging force of the coil spring a4, and the front end writing portion of the mechanical pencil unit 1 (refill) connected to the piece a2 has a barrel a1. When projecting forward from the front end opening, the piece a2 is locked by the locking part a5 provided in the shaft cylinder a1, and this protruding state is maintained.
When the clip a6 is advanced in this protruding state, the lead core x is extended from the front end of the mechanical pencil unit 1.
The basic structure shown in, for example, JP-A-2014-198439 can be applied to the multifunctional retractable writing instrument A.

<Second embodiment>
Next, the embodiment shown in FIG. 5 will be described. In this embodiment, a part of the mechanical pencil unit 1 is modified, and therefore the modified part will be mainly described in detail, and redundant detailed description will be omitted.

The mechanical pencil unit 2 shown in FIG. 5 is different from the mechanical pencil unit 1 in that the guide tubular portion 43b of the chuck support member 43 is replaced with a guide tubular portion 43b′, and the first buffer portion 44 is provided inside the guide tubular portion 43b′. It is replaced with the first buffer portion 44'.

The guide cylinder portion 43b' is provided with a recess 43b2 on the rear end side for fitting the first buffer portion 44'. The recess 43b2 forms a cylindrical space having an open rear.

The first buffer portion 44' is formed of an elastic material (for example, an elastomer resin or rubber) into a cylindrical shape that fits into the guide cylinder portion 43b' and allows the lead core x to be loosely inserted.
The first cushioning portion 44 ′ is fitted to the guide cylinder portion 43 b ′ and is integrally configured on the rear end side of the chuck support member 43. The means for fixing the guide tube portion 43b' may be, for example, fitting or adhesion.

Therefore, according to the mechanical pencil unit 2 shown in FIG. 5, the impact when the lead core x comes into contact with the chuck support member 43 can be alleviated by the elasticity of the first buffer portion 44′, and by extension, the lead core x. It is possible to prevent damage of x, abrasion, impact noise, and the like.

<Third embodiment>
The mechanical pencil unit 3 shown in FIG. 6 differs from the mechanical pencil unit 1 described above in that the guide tubular portion 43b of the chuck support member 43 is replaced with a guide tubular portion 43b″ that functions as a first cushioning portion. The part 44 is omitted.

The guide tube portion 43b″ is made of an elastic material (e.g., elastomer resin or rubber) and is formed into the same shape as the guide tube portion 43b.

Therefore, according to the mechanical pencil unit 3 shown in FIG. 6, the impact when the lead core x comes into contact with the chuck support member 43 can be alleviated by the elasticity of the guide cylinder portion 43b″, and by extension, the lead core x It is possible to prevent damage, wear and impact noise.

<Fourth Embodiment>
The mechanical pencil unit 4 shown in FIG. 7 differs from the mechanical pencil unit 1 in that the position at which the first buffer portion 44 is provided is changed from inside the slide cylinder portion 61 to inside the tank main body portion 62.
Also with this mechanical pencil unit 4, the impact when the lead core x comes into contact with the front and rear members in the tank main body 62 can be mitigated by the first cushioning portion 44 and the second cushioning portion 45, and by extension, It is possible to prevent damage to the lead core x, wear, impact noise, and the like.

In addition, according to the above-described embodiment, the first cushioning portion having the above-described configuration is provided on the front end side of the tank main body portion 62 and the rear end side of the chuck support member 43. It may be provided in at least a part of the range from the core tank portion to the lead tank portion. As another example other than the illustrated example, a mode in which the first buffer portion is provided on the center side in the front-rear direction of the tank body portion 62, It is also possible to adopt a mode in which a plurality of buffer parts are provided within the above range.

Further, according to the illustrated example, the second cushioning portion 45 is configured by an integral member, but as another example, the second cushioning portion 45 can be configured by a plurality of members.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the scope of the invention.

1, 2, 3, 4: Mechanical pencil unit 40: Chuck part 43: Chuck support member 43a: Support cylinder part 43b, 43b': Guide cylinder part 43b": Guide cylinder part (first buffer part)
44, 44': 1st buffer part 45: 2nd buffer part 60: Lead tank part 61: Slide cylinder part 62: Tank main body part x: Lead core A: Multi-functional retractable writing instrument M1: Lead core feeding mechanism M2 : Motion direction change mechanism

Claims (7)

A chuck portion that holds a lead core; a cylindrical chuck support member that supports the rear end side of the chuck portion and guides a lead core that is inserted from the rear side to the chuck portion; and the chuck portion and the chuck support member. A holding cylinder that is internally movable so as to be movable forward and backward, and a lead tank portion that engages with the holding cylinder so as to advance and retreat by a predetermined amount in opposition to the chuck support member and that supplies a lead core from the rear side to the chuck support member, A mechanical pencil unit configured to feed a lead core forward by advancing and retracting the lead tank portion.
A mechanical pencil unit, wherein at least a part of a range extending from the chuck support member to the lead tank portion is provided with a first buffer portion made of an elastic material and through which a lead lead is inserted. The mechanical pencil unit according to claim 1, wherein the first cushioning portion is provided in a cylindrical shape inside the lead tank portion, apart from a rear end of the chuck supporting member rearward. The lead tank portion includes a slide cylinder portion that is connected to the rear end side of the holding cylinder so as to be able to move forward and backward, and a tank main body portion that is connected to the slide cylinder portion and extends rearward,
The mechanical pencil unit according to claim 2, wherein the first cushioning portion is provided inside the slide cylinder portion. The mechanical pencil unit according to claim 1, wherein the first buffer portion is integrally provided on a rear end side of the chuck support member. The chuck support member is integrally configured from a support cylinder portion that supports the rear end side of the chuck portion, and a guide cylinder portion that is connected to the rear side of the support cylinder portion and that guides the core tank portion forward and backward. Is
The mechanical pencil unit according to claim 1, wherein the guide tube portion is entirely formed of an elastic material and functions as the first buffer portion. The mechanical pencil unit according to any one of claims 1 to 5, wherein a second buffer portion made of an elastic material is provided on the rear end side in the lead tank portion. A retractable writing instrument comprising the mechanical pencil unit according to claim 1.

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