JP2020131468A - Mechanical pencil unit, retractable writing instrument, and method of manufacturing mechanical pencil unit - Google Patents

Abstract

To improve the workability of connecting a plurality of cylinders in which the elastic biasing member is incorporated.SOLUTION: There is provided a mechanical pencil unit including a male-side cylinder portion, a female-side cylinder portion that is annularly fitted to one end side of the male-side cylinder portion in the expanded state, and a lead core feeding mechanism M1 for feeding out these two cylinder portions in an axial direction by a biasing member. The male-side cylinder portion has a fitting outer peripheral surface portion 12a fitted to the inner peripheral surface of the female-side cylinder portion, and an annular inclined surface 12b that is continuous with the fitting outer peripheral surface portion 12a and whose diameter is gradually reduced toward the one end side. The female-side cylinder portion is set such that the inner diameter before the diameter expansion is temporarily fitted to the annular inclined surface 12b.SELECTED DRAWING: Figure 3

Description

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

Conventionally, in relation to this type of invention, for example, Patent Document 1 includes a lead lead feeding mechanism for feeding a lead core sandwiched by a chuck portion forward by a predetermined operation, and the lead core feeding mechanism, and the chuck portion. To the lead tank portion and the lead tank portion connected so as to supply the lead core from the rear side to the lead lead feeding mechanism and advance and retreat a predetermined amount to the holding cylinder, and the lead core tank portion. The first urging member that urges the chuck portion forward with a urging force stronger than the preset writing pressure and the holding cylinder urging the holding cylinder forward with respect to the front end portion of the first urging member. A mechanical pencil unit including a second mechanical pencil having a smaller urging force than the first urging member is described. Then, if this mechanical pencil unit is housed in a shaft cylinder, a haunting writing instrument can be easily constructed.
According to this haunting writing instrument, when an excessive downward pressing force is applied to the lead core, the chuck portion is retracted, the first urging member contracts, and the second urging member expands. , The lead core can be prevented from breaking or being damaged.

Japanese Unexamined Patent Publication No. 2017-165096

By the way, according to the prior art, in order to incorporate the above-mentioned complicated mechanism, the holding cylinder is configured by connecting a plurality of cylinder portions (specifically, first to third cylinder portions), and a plurality of these holding cylinders. A plurality of urging members are contained in the cylinder portion of the above in a resilient state.
Therefore, when connecting the plurality of tubular portions, the elastic force of the urging member may act on the connecting members, which may hinder the connecting operation.

In view of such problems, the present invention has the following configurations.
The male side cylinder part, the female side cylinder part that is annularly fitted to one end side of the male side cylinder part in an enlarged diameter state, and these two cylinder parts are elastically repelled in the axial direction by an urging member. In a mechanical pencil unit provided with a lead core feeding mechanism, the male side cylinder portion includes a fitting outer peripheral surface portion fitted to the inner peripheral surface of the female side cylinder portion, and the fitting outer peripheral surface portion continuous with the fitting outer peripheral surface portion. An annular inclined surface whose diameter is gradually reduced toward one end side is provided, and the female side cylinder portion is characterized in that the inner diameter before the diameter expansion is set so as to be temporarily fitted to the annular inclined surface. Mechanical pencil unit.

Since the present invention is configured as described above, it is possible to improve the connection workability of a plurality of tubular portions incorporating the urging member in the elastic state.

It is a vertical cross-sectional view which shows an example of the mechanical pencil unit which concerns on this invention. It shows the state immediately before connecting the second cylinder to the first cylinder. It is an enlarged vertical sectional view of the main part which shows the state of temporarily fitting a 2nd cylinder part with respect to the 1st cylinder part in order (a)-(b). It is an enlarged vertical sectional view of the main part which shows the state of this fitting of the 2nd cylinder part with respect to the 1st cylinder part in order in (a)-(b). It is an internal structural drawing which shows an example of the writing instrument provided with the mechanical pencil unit.

In this embodiment, the following features are disclosed.
The first feature is that the male side cylinder part, the female side cylinder part that is annularly fitted to one end side of the male side cylinder part in an enlarged diameter state, and these two cylinder parts are shafted by an urging member. In a mechanical pencil unit provided with a lead core feeding mechanism that repels in a direction, the male side cylinder portion includes a fitting outer peripheral surface portion fitted to the inner peripheral surface of the female side cylinder portion and the fitting outer peripheral surface portion. An annular inclined surface that is continuous with the surface portion and gradually reduces in diameter toward one end side is provided, and the female side cylinder portion is set so that the inner diameter before the diameter expansion is temporarily fitted to the annular inclined surface. are doing. (See FIGS. 1 to 4).
According to this configuration, the female side cylinder is temporarily fitted to the annular inclined surface of the male side cylinder to maintain the elastic state of the internal urging member, and then the fitting outer circumference of the male side cylinder is maintained. The female side cylinder can be press-fitted into the surface. Therefore, it is possible to prevent the elastic force of the urging member from interfering with the connection work of the plurality of cylinders.

As a second feature, the male side tubular portion has a tubular guide surface portion on one end side of the annular inclined surface (see FIG. 3).

The third feature is that the inclination angle of the annular inclined surface with respect to the axis of the male side cylinder is set within a range of less than 15 ° (see FIG. 3).

The fourth feature is that the mechanical pencil unit is provided to form a haunting writing instrument (see FIG. 5).

The fifth feature is the method for manufacturing the sharp pencil unit, in which the step of mounting the urging member in the female side cylinder portion and after that, the female side cylinder portion facing the male side cylinder portion. To temporarily fit the female side cylinder to the annular inclined surface of the male side cylinder, temporarily stop the movement, and hold the urging member in a compressed state, and after that. The step of restarting the movement and main fitting the female side cylinder portion to the fitting outer peripheral surface portion of the male side cylinder portion is included (see FIGS. 3 and 4).

<Specific embodiment>
Next, a specific embodiment 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. Further, "front" means a direction in which the lead core is extended on one side in the axial direction. Further, "rear" means the side in the opposite direction to the one side.

The mechanical pencil unit 1 shown in FIG. 1 is fed from a holding cylinder 10, a lead core feeding mechanism M1 for feeding forward a lead core x sandwiched between the rear sides of the holding cylinder 10, and a lead core feeding mechanism M1. After the holder 20 through which the lead core x is inserted and protruding from the front end opening, the motion direction changing mechanism M2 that advances the holder 20 toward the holding cylinder 10 by the radial force component applied to the holder 20, and the holding cylinder 10. A lead tank portion 60 connected to the end side is provided, and the lead core x is fed out by an operation of moving the lead tank portion 60 forward and backward.

The holding cylinder 10 has a first cylinder portion 11 that inserts the holder 20 through the front end opening and projects forward, and a second cylinder portion that is concentrically connected to the rear end side of the first cylinder portion 11. A portion 12 (male side cylinder portion) and a third cylinder portion 13 (female side cylinder portion) connected concentrically to the rear end side of the second cylinder portion 12 are integrally provided.

The second tubular portion 12 is formed of a hard material such as metal in a tubular shape extending in the front-rear direction, and its front end side is press-fitted or screwed to the first tubular portion 11.

The second tubular portion 12 functions as a male side tubular portion that is inserted and fitted to the front end side of the third tubular portion 13.
More specifically, on the rear end side of the second tubular portion 12, a cylindrical fitting outer peripheral surface portion 12a that overlaps and fits on the inner peripheral surface on the front end side of the third tubular portion 13 and this fitting It was fitted to the annular inclined surface 12b which was continuous with the outer peripheral surface portion 12a and gradually reduced in diameter toward the rear, the cylindrical guide surface portion 12c which was continuous to the rear side of the annular inclined surface 12b, and the fitting outer peripheral surface portion 12a. An annular step portion 12d that contacts the front end portion of the third tubular portion 13 to position the second tubular portion 12, and a third tubular portion 13 provided between the step portion 12d and the fitting outer peripheral surface portion 12a. An annular recess 12e is provided to allow burrs and the like at the front end to escape.

The annular inclined surface 12b is an annular inclined surface that can come into contact with the inner edge of the front end of the third tubular portion 13 over the entire circumference.
The inclination angle of the annular inclined surface 12b with respect to the axis of the second tubular portion 12 is set to 1 ° to less than 15 °.

The third tubular portion 13 is formed of a hard material such as metal in a tubular shape extending in the front-rear direction, and functions as a female side tubular portion that is annularly fitted to the rear end side of the second tubular portion 12.
The initial inner diameter D of the third tubular portion 13 before the diameter is expanded is set so that the inner edge of the front end of the third tubular portion 13 is in contact with an intermediate portion of the annular inclined surface 12b in the front-rear direction.
The third tubular portion 13 is annularly pressed against the fitting outer peripheral surface portion 12a on the rear end side of the second tubular portion 12 (male side tubular portion) in a state where the diameter is expanded.

In FIG. 3, reference numeral 13a is an annular chamfered portion that improves workability when the third tubular portion 13 is fitted to the second tubular portion 12. The chamfered portion 13a is formed in a C chamfered shape in the illustrated example, but it can also be formed in an R chamfered shape.

Further, the lead core feeding mechanism M1 has a core breaker 30 held on the front end side in the second tubular portion 12, a chuck portion 40 that moves forward and backward on the rear side of the core breaker 30, and a rear portion with respect to the chuck portion 40. A clutch ring 41 that fits in an annular shape from the side, a substantially tubular 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 rear end of the support member 43. A guide cylinder portion 44 connected to the side to guide the advance / retreat of the core tank portion 60, and first to third urging members 51 to 53 are provided.
The lead core feeding mechanism M1 feeds out the lead core x sandwiched between the chuck portions 40 by the advancing / retreating movement transmitted from the core tank portion 60. Further, the lead core feeding mechanism M1 retracts the chuck portion 40 and the like together with the lead core x when a backward urging force stronger than a preset writing pressure is applied to the lead core x sandwiched between the chuck portions 40. ..

The first urging member 51 faces the core tank portion 60 and urges the clutch receiver 42 forward with a force stronger than a preset normal writing pressure.

The second urging member 52 is a compression coil spring whose urging force is larger than that of the holder urging member 23. The front end side thereof is locked to the second tubular portion 12, and the rear end side thereof is the clutch receiver 42. It is locked and repelled between these members. The urging force of the second urging member 52 is set to be larger than the resistance force in the advancing / retreating direction due to friction between the core breaker 30 and the lead core x or the like.

The third urging member 53 is a compression coil spring in which the front end side is locked to the clutch receiver 42 and the rear end side is locked to the support cylinder portion 43, and the chuck portion 40, the support member 43, and the guide cylinder portion 44. Etc. are urged backwards.

Therefore, an axial tensile force acts on the second tubular portion 12 and the third tubular portion 13 due to the elastic force of the first urging member 51 and the second urging member 52.

The holder 20 is integrally composed 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 by the holding cylinder 10 so as to be able to advance and retreat. The holder main body 21 and the receiving portion 22 can be integrated members.

The motion direction changing mechanism M2 is composed of a first tubular portion 11, a cam slope 21a of the holder 20, a holder urging member 23 that urges the holder 20 rearward, and the like, and has a diameter applied to the holder 20 via a lead core x. The holder 20 is advanced with respect to the lead core x, the holding cylinder 10, and the like by the force component in the direction.

It is possible to apply the one of Patent Document 1 to the basic structures of the lead core feeding mechanism M1 and the motion direction changing mechanism M2.

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

Next, the characteristics of the mechanical pencil unit 1 having the above configuration in terms of manufacturing method will be described.

In the method of manufacturing the mechanical pencil unit 1, a step of mounting a component including a first urging member 51 and a second urging member 52 in a third tubular portion 13 (female side tubular portion), and after that , The third tubular portion 13 (female side tubular portion) is advanced relative to the second tubular portion 12, and the inner edge of the front end of the third tubular portion 13 is temporarily fitted to the annular inclined surface 12b of the second tubular portion 12. In combination, the step of temporarily stopping the movement to hold the first urging member 51 and the second urging member 52 in the compressed state, and after that, the movement is restarted and the second cylinder portion The step of main fitting the front end side of the third tubular portion 13 to the fitting outer peripheral surface portion 12a of the 12 is included.

More specifically, the third tubular portion 13 (female side tubular portion) is inserted with a component including the first urging member 51 and the second urging member 52 from the front side thereof. , Fig. 2 is configured as an integrated unit shown on the lower right side.

After that, the third tubular portion 13 is idlely fitted to the guide surface portion 12c of the second tubular portion 12 (see FIG. 3A).
Then, the third tubular portion 13 is advanced with respect to the second tubular portion 12, and the inner edge of the front end of the third tubular portion 13 is pressed against the annular inclined surface 12b of the second tubular portion 12 to temporarily fit the third tubular portion 13. At the same time (see FIG. 3B), the movement of the third tubular portion 13 is temporarily stopped. In this temporary fitting state, the first urging member 51 and the second urging member 52 are held in the compressed state.

Next, the advance of the third tubular portion 13 relative to the second tubular portion 12 is restarted, the diameter of the third tubular portion 13 is increased, and the fitting outer peripheral surface portion 12a of the second tubular portion 12 is expanded. (See FIGS. 4A and 4B). Then, the third tubular portion 13 is further advanced, and its front end portion abuts on the step portion 12d to be positioned.
These fitting operations are performed using, for example, a well-known press-fitting machine or the like.

On the other hand, the first tubular portion 11 contains the holder 20 and the holder urging member 23, and is configured in the shape of an integrated unit shown on the upper left side of FIG. The first tubular portion 11 is connected to the front end side of the second tubular portion 12 by screwing, fitting, or the like.
The step of connecting the first tubular portion 11 to the second tubular portion 12 may be after the step of connecting the second tubular portion 12 and the third tubular portion 13, but it should be before. Is also possible.

Therefore, according to the mechanical pencil unit 1 of the above embodiment and the manufacturing method thereof, after the second tubular portion 12 and the third tubular portion 13 are integrated by temporary fitting, the second tubular portion 12 and the second tubular portion 12 and the second tubular portion 13 are integrated. The tubular portion 13 of No. 3 can be set in the press-fitting machine for main fitting, and the workability thereof is good.
That is, for example, when the second tubular portion 12 is inserted into the third tubular portion 13 without performing the temporary fitting, the second tubular portion 12 is separated by the elastic force of the internal urging member, and the subsequent press-fitting machine It is assumed that the work cannot be smoothly shifted to the work using the above, but in the above embodiment, such a problem can be eliminated and the work can be smoothly performed.

Then, as illustrated in FIG. 5, the mechanical pencil unit 1 having the above configuration is incorporated into the multifunctional haunting writing instrument A.
The multifunctional haunting writing instrument A projects the front end writing portion of the refill connected to the advancing piece a2 (or a3) forward from the front end of the barrel a1 by the operation of selectively advancing the plurality of pieces a2 and a3. Let me. According to the illustrated example, the refill is a mechanical pencil unit 1 or a ballpoint pen refill 9.
For example, the piece a2 having the 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 is the shaft cylinder a1. When the piece a2 protrudes forward from the front end opening, the piece a2 is locked by the locking portion a5 provided in the barrel a1, and this protruding state is maintained.
If the operation of advancing the clip a6 is performed in this protruding state, the lead core x is extended from the front end of the mechanical pencil unit 1.
For example, the basic structure shown in Japanese Patent Application Laid-Open No. 2014-198439 can be applied to this multifunctional haunting writing instrument A.

In the above embodiment, the connection structure and connection method of the second cylinder portion 12 (male side cylinder portion) and the third cylinder portion 13 (female side cylinder portion) are mechanical pencils provided with the motion direction changing mechanism M2. Although it is applied to the pencil unit 1, as another example, it is also possible to apply the connection structure, the connection method, and the like to a mechanical pencil unit that does not have the motion direction changing mechanism M2.

Further, in the above embodiment, the second cylinder portion 12 is a male side cylinder portion and the third cylinder portion 13 is a female side cylinder portion, but as another example, the male-female relationship can be reversed. Is.

Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed without changing the gist of the present invention.

1: Mechanical pencil unit 10: Holding cylinder 11: First cylinder 12: Second cylinder (male side cylinder)
12a: Fitting outer peripheral surface portion 12b: Circular inclined surface 12c: Guide surface portion 13: Third tubular portion (female side tubular portion)
20: Holder 60: Core tank part A: Multi-functional indentation type writing instrument M1: Lead lead feeding mechanism M2: Movement direction change mechanism

Claims (5)

The male side cylinder part, the female side cylinder part that is annularly fitted to one end side of the male side cylinder part in an expanded state, and these two cylinder parts are elastically repelled in the axial direction by an urging member. In a mechanical pencil unit equipped with a lead core feeding mechanism,
The male side cylinder portion includes a fitting outer peripheral surface portion fitted to the inner peripheral surface of the female side cylinder portion, and an annular inclined surface that is continuous with the fitting outer peripheral surface portion and gradually reduces in diameter toward one end side. And are provided,
The mechanical pencil unit is characterized in that the inner diameter of the female side cylinder portion before the diameter expansion is set so as to be temporarily fitted to the annular inclined surface. The mechanical pencil according to claim 1, wherein the male side tubular portion has a tubular guide surface portion on one end side of the annular inclined surface. The mechanical pencil unit according to claim 1 or 2, wherein the inclination angle of the annular inclined surface with respect to the axial center of the male side cylinder portion is set within a range of less than 15 °. A haunting writing instrument provided with the mechanical pencil unit according to any one of claims 1 to 3. A step of mounting the urging member in the female side cylinder portion, and after that, the female side cylinder portion is moved relative to the male side cylinder portion and the female is moved to the annular inclined surface of the male side cylinder portion. A step of temporarily fitting the side cylinder portion and temporarily stopping the movement to hold the urging member in a compressed state, and after that, restarting the movement and fitting outer peripheral surface portion of the male side cylinder portion. The method for manufacturing a sharp pencil unit according to any one of claims 1 to 3, further comprising a step of main fitting the female side cylinder portion.

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