JP2020116913A - Mechanical pencil unit, retractable writing instrument, and method for manufacturing mechanical pencil unit - Google Patents

Abstract

To more reliably fix a core breaker.SOLUTION: A mechanical pencil unit includes: a lead core delivering mechanism M1 where a lead core x is inserted into a core breaker 30 and delivering the core; and a holding cylinder 10 incorporating the lead core delivering mechanism M1. The holding cylinder 10 is configured to connect a plurality of cylinder parts by the front and the rear thereof. The core breaker 30 is supported while put between the front and rear cylinder parts.SELECTED DRAWING: Figure 2

Description

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

Conventionally, in connection with this type of invention, for example, in Patent Document 1, a holding cylinder and a front opening of the holding cylinder are inserted to project forward from the front end of the holding cylinder and to be able to move forward and backward with respect to the holding cylinder. A supported holder, a lead core feeding mechanism that inserts a lead core into a core breaker and feeds it toward the holder, and a radial force applied from the lead core to the holder causes the holder to move forward relative to the holding cylinder and the lead core. There is described a mechanical pencil unit including a movement direction changing mechanism for tilting the holder and a holder biasing member for biasing the holder rearward with respect to the holding cylinder. If the mechanical pencil unit is housed in the barrel, the retractable writing instrument can be easily constructed.
According to this retractable writing instrument, the mechanical pencil unit is moved forward by a predetermined operation, and when the holder at the front end of the mechanical pencil unit is projected from the opening at the front end of the barrel, the pencil core is projected radially from the holder. When the force is applied, the holder moves forward relative to the holding cylinder and the lead core, so that the holder can cover and protect the lead core.
Further, when the radial force is removed, the retracting holder can be brought into contact with the front end portion of the elastic core breaker to mitigate the contact noise.

JP, 2017-159580, A

However, according to the above-mentioned conventional technique, since the core breaker is fixed to the inner peripheral surface of the holding cylinder by press fitting or the like, its fixed portion may be subject to any impact such as contact with the holder when retracted. When it is received, it may shift or come off.

In view of such a problem, the present invention has the following configurations.
In a mechanical pencil unit including a lead core feeding mechanism adapted to feed a lead core through a lead breaker, and a holding barrel having the lead core feeding mechanism therein, the holding barrel includes a plurality of tubular portions arranged in front and rear directions. The mechanical pencil unit, wherein the lead breaker is supported by being sandwiched between the front and rear cylindrical portions.

Since the present invention is configured as described above, the core breaker can be more reliably fixed.

It is a longitudinal cross-sectional view showing an example of a mechanical pencil unit according to the present invention. FIG. 6 is a vertical cross-sectional view showing a state in which the lead breaker is inserted into the first tubular portion and the second tubular portion is connected to 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 the action of the movement direction conversion mechanism, (a) shows a normal writing state, (b) shows a state in which the holder is advanced. In addition, hatching indicates a portion that has moved from the previous state.

The following features are disclosed in the present embodiment.
A first feature is a mechanical pencil unit, which includes a lead core feeding mechanism in which a lead core is inserted into a core breaker and is fed, and a holding cylinder having the lead core feeding mechanism therein. In the above, the holding cylinder is configured by connecting a plurality of cylinder parts to the front and rear, and the core breaker is supported by being sandwiched between the front and rear cylinder parts (see FIGS. 1, 2 and 4 ). ).

A second feature is that a flange portion that projects outward in the radial direction is provided on the rear end side of the core breaker, and the flange portion is sandwiched between the cylindrical portions that are adjacent to each other in the front and rear (FIGS. 1 and 2 ). And FIG. 4).

A third feature is that the holder is inserted into the front end opening of the holding cylinder on the front side of the core breaker and protrudes forward, and the holder is formed by the radial force component applied to the holder from the lead core. A movement direction conversion mechanism for advancing and inclining relative to the holding cylinder; and a holder urging member for urging the holder backward, the core breaker having an inner peripheral surface of the holding cylinder on the front end side thereof. Has a reduced diameter portion with a reduced diameter between them, and the reduced diameter portion elastically receives the rear end portion of the holder (see FIGS. 1, 2 and 4).

The fourth feature is that the adjacent front and rear cylindrical portions are screwed and connected (see FIG. 2 ).

A fifth feature is that the front and rear adjacent tubular portions are connected and fixed by press fitting.

A sixth feature is that a retractable writing instrument is configured by including the mechanical pencil unit (see FIG. 3).

A seventh feature is a method of manufacturing the mechanical pencil unit, which includes a step of sandwiching the core breaker between the front and rear tubular portions when connecting the tubular portions (see FIG. 2).

<Specific 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 lead core feeding mechanism M1 configured to feed the lead core x through a lead breaker 30, a holding cylinder 10 including the lead core feeding mechanism M1, and a lead breaker 30. Also on the front side, the holder 20 is inserted into the front end opening of the holding cylinder 10 and projects forward, and the holder 20 is opposed to the holding cylinder 10 and the lead core x by the radial force component applied to the holder 20 from the lead core x. It is provided with a movement direction conversion mechanism M2 that advances and inclines, and a lead tank portion 60 connected to the rear end side of the holding cylinder 10. The lead core x is fed out by the forward/backward operation of the lead tank portion 60.

The holding tube 10 is connected to the first tube portion 11 that projects forward by inserting the holder 20 into the front end opening portion, and the core breaker 30 that is concentrically connected to the rear end side of the first tube portion 11. The second tubular portion 12 that sandwiches and supports the first tubular portion 11 and the third tubular portion 13 concentrically connected to the rear end side of the second tubular portion 12 are integrated. It is equipped with
The second tubular portion 12 and the third tubular portion 13 can also be configured as an integral member.

The first tubular portion 11 is formed of a hard material such as metal into a substantially cylindrical shape. On the inner peripheral surface on the rear end side of the first tubular portion 11, an annular step portion 11a for sandwiching the core breaker 30 between the first tubular portion 11 and the second tubular portion 12, and a rear side of the step portion 11a. Thus, an annular joined surface 11b that is joined to the outer peripheral surface of the second tubular portion 12 on the front end side is formed.

The second tubular portion 12 is formed of a hard material such as metal into a tubular shape extending in the front-rear direction.
On the front end side of the outer peripheral surface of the second tubular portion 12, a joining surface 12a to be joined by being overlapped with a joined surface 11b on the rear end side of the first tubular portion 11 and a rear side of the joining surface 12a. The stepped portion 12b formed by the diameter is formed (see FIG. 2).

According to the illustrated example, the joined surface 11b and the joining surface 12a are a male screw portion and a female screw portion, which are screwed and connected and fixed.
As another example, the joint surface 12a may be press-fitted to the joint surface 11b.

The step portion 12b on the side of the second tubular portion 12 contacts the rear end portion of the first tubular portion 11 to position the second tubular portion 12 in the front-rear direction.

The core breaker 30 is made of an elastic material such as an elastomer resin or a synthetic rubber and is formed into a tapered substantially cylindrical shape, and elastically receives the rear end of the receiving portion 22 of the holder 20.

More specifically, the core breaker 30 includes a flange portion 31 that projects radially outward from the front end side of the rear end side of the core breaker 30 and an inner portion of the first tubular portion 11 that extends forward of the flange part 31. It has a diameter-reduced portion 32 whose diameter is reduced while ensuring a gap s (see FIG. 4) between the peripheral surface and the peripheral surface.

The flange portion 31 is formed in an annular shape that can be locked to the step portion 11 a of the first tubular portion 11. The collar portion 31 is sandwiched between the step portion 11a and the front end portion of the second tubular portion 12 and elastically contracts.
Note that, as another example of the flange portion 31, it is possible to use a plurality of protrusions that partially protrude outward in the radial direction in the circumferential direction.

The reduced diameter portion 32 is formed in a tapered cylindrical shape whose diameter is gradually reduced toward the front, and the gap s with the inner peripheral surface of the first tubular portion 11 is gradually increased toward the front ( (See FIG. 4).
As another example of the reduced diameter portion 32, it is also possible to adopt a cylindrical shape in which the diameter is reduced stepwise with respect to the flange portion 31.

Further, the movement direction conversion mechanism M2 is configured by the first tubular portion 11, the holder 20 that is included in the first tubular portion 11 and protrudes forward, the holder biasing member 23 that biases the holder 20 backward, and the like. , The holder 20 is moved forward relative to the lead core x and the holding cylinder 10 by the radial force component applied to the holder 20 via the lead core x.

The holder 20 is integrally configured of a holder main body portion 21 having a cam slope 21a and a receiving portion 22 connected to the rear side of the holder main body portion 21, and is supported so as to be movable back and forth with respect to the holding cylinder 10. The holder 20 is slightly inclined when it is advanced by the radial force component applied to the lead core x (see FIG. 4). In addition, the holder main body 21 and the receiving portion 22 may be an integral member.

As shown in FIG. 1, the lead lead-out mechanism M1 includes a lead breaker 30 described above, a chuck portion 40 that moves back and forth with respect to the lead breaker 30, and a clutch that annularly fits the chuck portion 40 from the rear side. A ring 41, a substantially cylindrical clutch receiver 42 that receives the clutch ring 41 from its rear side, a support member 43 that supports the rear end side of the chuck portion 40, and a core tank that is connected to the rear end side of the support member 43. A guide cylinder portion 44 for guiding the forward/backward movement of the portion 60 and first to third biasing members 51 to 53 are provided.
The lead core feeding mechanism M1 feeds the lead core x sandwiched by the chuck portion 40 by the forward/backward movement transmitted from the lead tank portion 60. The lead core feeding mechanism M1 also retracts the lead core x together with the lead core x when a backward biasing force stronger than a preset writing pressure is applied to the lead core x sandwiched between the chuck portions 40. ..

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.

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

Next, the characteristics of the mechanical pencil unit 1 having the above-described structure in terms of the manufacturing method will be described.
In the method of manufacturing the mechanical pencil unit 1, as shown in FIG. 2, when connecting the front and rear first tubular portions 11 and the second tubular portion 12, the core breaker 30 is provided between the tubular portions 11 and 12. Including the step of sandwiching.

More specifically, first, the core breaker 30 is inserted into the rear end side of the first tubular portion 11 from the rear side thereof. The core breaker 30 is positioned such that the front end surface of the collar portion 31 abuts the step portion 11a (see FIG. 2).

Next, the portion of the joining surface 12a of the second tubular portion 12 is inserted to the rear side of the core breaker 30 in the first tubular portion 11, and the joined surface 11b (female screw) on the first tubular portion 11 side is inserted. The joint surface 12a (male thread portion) on the second tubular portion 12 side is screwed into the portion). Then, due to this screwing, the second tubular portion 12 advances until the stepped portion 12b comes into contact with the rearmost end portion of the first tubular portion 11.
With this forward movement, the flange portion 31 of the core breaker 30 is sandwiched between the step portion 11a on the side of the first tubular portion 11 and the foremost end portion of the second tubular portion 12, and the collar portion 31 elastically moves. Contract.
For this reason, the loosening of the screwed state of the joined surface 11b (female screw portion) and the joint surface 12a (male screw portion) can be prevented by the elastic force of the collar portion 31.

Then, the mechanical pencil unit 1 having the above 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.

According to the multifunctional retractable writing instrument A having the above-described configuration, as shown in FIGS. 4A and 4B, the lead core x is strongly pressed against the writing surface p (for example, the paper surface), and the lead core x is then pressed. When an excessive radial force is applied to the holder 20, the cam sloped surface 21a slides on 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.
Then, when the radial force is removed, the holder 20 is retracted by the urging force of the holder urging member 23, the rear end of the receiving portion 22 contacts the core breaker 30, and the core breaker 30 is elastic. Then, it is deformed by compression and returns to the state shown in FIG.
At the time of the retreat, the reduced diameter portion 32 on the front end side of the core breaker 30 flexibly elastically deforms toward the gap s side with the inner peripheral surface of the first tubular portion 11.
Therefore, it is possible to effectively reduce the impact at the time of the contact, prevent the impact noise from being generated, and prevent the core breaker 30 from being displaced or disengaged due to the impact.

Further, even when the lead core x bends as the holder 20 moves forward and tilts (see FIG. 4B), the lead breaker can be elastically deformed so as to follow the bending of the lead core x. Therefore, breakage of the lead core x due to the bending can be prevented.

According to the above-described embodiment, the movement direction conversion mechanism M2 is provided as a particularly preferable mode, but as another example, the above-described core breaker 30 and the like are provided for the mechanical pencil unit that does not include the movement direction conversion mechanism M2. It is also possible to apply the structure of.

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

1: Mechanical pencil unit 10: Holding cylinder 11: First cylinder part 12: Second cylinder part 13: Third cylinder part 20: Holder 30: Core breaker 31: Collar part 32: Reduced diameter part 60: Core tank Part s: Gap x: Lead core A: Multi-functional retractable writing instrument M1: Lead core feeding mechanism M2: Movement direction conversion mechanism

Claims (7)

In a mechanical pencil unit including a lead core feeding mechanism adapted to feed a lead core through a core breaker, and a holding cylinder having the lead core feeding mechanism therein,
The holding cylinder is configured by connecting a plurality of cylinders to the front and rear,
The mechanical pencil unit, wherein the core breaker is supported by being sandwiched between the front and rear cylindrical portions. The mechanical pencil according to claim 1, wherein a flange portion protruding outward in the radial direction is provided on the rear end side of the core breaker, and the flange portion is sandwiched between the cylindrical portions adjacent to each other in the front and rear. unit. A holder that is inserted into the front end opening of the holding cylinder and projects forward from the core breaker, and a forward force that moves the holder relative to the holding cylinder by a radial force component applied to the holder from the lead core. And a tilting movement direction conversion mechanism, and a holder biasing member that biases the holder backward.
The core breaker has, on the front end side thereof, a diameter-reduced portion whose diameter is reduced so as to secure a gap between it and the inner peripheral surface of the holding cylinder. The mechanical pencil unit according to claim 1 or 2, wherein the mechanical pencil unit is received. The mechanical pencil unit according to any one of claims 1 to 3, characterized in that the front and rear adjacent tubular portions are screw-connected. The mechanical pencil unit according to any one of claims 1 to 3, wherein the adjacent front and rear cylindrical portions are connected and fixed by press-fitting. A retractable writing instrument, comprising the mechanical pencil unit according to claim 1. The method for manufacturing a mechanical pencil unit according to claim 1, further comprising a step of sandwiching the core breaker between the cylinder parts when connecting the front and rear cylinder parts.

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