JP2020111040A - Writing instrument with core break prevention mechanism - Google Patents

Abstract

To provide a writing instrument with a core break prevention mechanism, which allows a slider to move forward and protect the core when an excessive writing pressure is applied to the tip of the core during writing, regardless of the pressure applied due to the excessive writing pressure.SOLUTION: A grip portion 4 is provided on the outer circumference of the main body so as to be movable in the axial radial direction and the axial length direction, and is biased rearward by a retreat spring 29. The tip of the grip portion abuts on a tip abutment tool 22 movable in the axial length direction, and a push tool 30 compresses the retreat spring by the tip abutment tool. A slider 6 has a spring receiving portion 39 on which the urging force of the retreat spring acts indirectly or directly so as to be urged rearward by the retreat spring. When the retreat spring is compressed, a moving space is formed between the retreat spring and the spring receiving portion, and the slider advances along the moving space by the forward spring or the slider's own weight to protect the tip of the core.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument with a core break preventing mechanism that prevents core breaks when a writing pressure is excessively applied.

In writing instruments such as mechanical pencils, there is a writing instrument with a core break prevention mechanism that protects the lead by advancing the lead holder protruding from the tip of the barrel so that the lead does not break when excessive writing pressure is applied. (For example, see Patent Document 1). The writing instrument described in Patent Document 1 pushes the lead holder forward by a force applied in the axial direction of the barrel when the barrel is tilted by a large writing pressure, and advances the tip of the lead holder to the outer periphery of the lead to move the lead. It is a configuration that covers. At this time, a large pressure force due to excessive writing pressure acts directly on the tip of the lead holder, pressing the tip strongly against the paper surface. There is a risk of breaking.

In the configuration of Patent Document 1 described above, since the lead feeding mechanism for feeding the writing lead must be tilted in the barrel, the writing lead may be damaged. There is also proposed a mechanism for protecting the lead by tilting the grip or the front shaft of the barrel in the radial direction of the shaft when excessive writing pressure is applied without tilting the lead-out mechanism in the barrel. See Patent Documents 2 and 3). However, the mechanical pencil described in Patent Document 2 has a configuration in which, when an excessive writing pressure is applied, the grip is tilted to move the lead-out unit rearward in the axial direction. Then, the lead feeding unit suddenly retracts and the lead immerses, which interrupts the writing work and makes it difficult to use.

Further, in the mechanical pencil described in Patent Document 3, the lead-out unit is configured to move forward when the front shaft is tilted with respect to the rear shaft. Since the lead feeding unit is directly advanced with a correspondingly large pressing force to press the mouthpiece against the paper surface, the paper surface may be damaged.

Japanese Patent No. 5827675 (claims, paragraphs 0009 to 0011, FIGS. 1 and 4) JP, 2017-13286, A (claim, paragraph 0023, Drawing 3, Drawing 4) JP, 2017-13289, A (claim, paragraph 0039, Drawing 2, Drawings 4-6)

The problem to be solved by the present invention is to provide a taper (base) provided at the tip of the barrel body with a writing instrument provided with a slider that protects the core so that the slider can be moved back and forth when excessive writing pressure acts on the barrel of the barrel body. It is an object of the present invention to provide a writing instrument with a core breakage prevention mechanism, in which the slider can be moved forward by a force applied in the radial direction or the axial direction, and the core can be protected without damaging the paper surface.

According to the present invention, a writing instrument of a type that comprises a taper provided at the tip of the main body and a slider inserted in the taper so as to be movable back and forth, and the core is fed out by a lead feeding mechanism provided in the main body and protected by the slider. In the outer periphery of the main body, the grip portion is provided so as to be movable in the axial radial direction and the axial length direction, and is biased by the retraction spring to the rear of the main body; And a pusher that moves forward when the tip abutment moves forward and compresses the retraction spring, and the slider moves backward so as to be biased backward by the retraction spring. It has a spring receiving portion on which the biasing force of the spring acts, and when the retracting spring is compressed by a pressing tool, a moving space is formed between the retracting spring and the spring receiving portion, and the slider can advance along the moving space. There is provided a writing instrument with a core break prevention mechanism, preferably, when the moving space is generated, the slider is advanced by the forward spring or the own weight of the slider. A writing instrument with a mechanism is provided.

Further, according to the present invention, the slider has a small diameter portion extending in the axial direction, the spring receiving portion is formed at a rear portion of the small diameter portion, and a receiving ring is provided between the retracting spring and the pressing tool. The receiving ring is provided with a locking claw protruding to the small diameter part and capable of engaging with the spring receiving part, and the moving space is formed between the locking claw and the spring receiving part when the receiving ring is advanced by a pusher. The writing instrument with the core breakage prevention mechanism is provided.

Further, according to the present invention, a pressing piece that contacts the rear end of the retraction spring is formed at the tip of the pressing tool, and a sliding member that slidably fits the pressing piece around the outer periphery of the slider. A moving groove is formed, and the periphery of the opening end of the sliding groove serves as the spring receiving portion, and when the pushing tool is retracted, the rear end of the retraction spring comes into contact with the tip of the pressing piece and the spring receiving portion, and pushes. There is provided the writing instrument with a core breakage prevention mechanism, wherein the movement space is formed between a retraction spring and a spring receiving portion when the tool advances.

As described above, the writing instrument of the present invention comprises a taper provided at the tip of the main body and a slider inserted in the taper so as to be movable back and forth, and the lead is fed out by a lead feeding mechanism provided in the main body to remove the outer circumference. It is configured to protect with a slider. On the outer periphery of the main body, a grip is provided with a tip movably in the axial direction and the axial direction, and is urged by a retreat spring to the rear of the main body, and a front end of the grip is abutted against the grip. A movable tip abutment is provided. A pusher is provided in the main body so as to move forward when the tip abutment tool moves forward to compress the retraction spring. The slider is provided with a spring receiving portion on which the urging force of the retreat spring acts so as to be urged rearward by the retreat spring. Then, when the tip of the grip portion moves in the axial direction or the radial direction due to excessive writing pressure, the retraction spring is compressed through the tip abutment tool and the pushing tool that move forward, and the retraction spring and the spring receiver. Since the moving space is formed between the parts, the slider can be advanced along the moving space, and can be advanced to a position that sufficiently covers the outer periphery of the core to prevent core breakage. At this time, if the slider is moved by its own weight when the movement space is generated, the structure is simplified, and if the forward spring is pressed against the slider, the slider is surely moved forward to prevent core breakage. can do.

Further, the slider is provided with a small diameter portion extending in the axial direction, the spring receiving portion is formed in the rear portion of the small diameter portion, and a receiving ring is provided between the retreat spring and the pressing tool, and the receiving ring is provided with the small diameter portion. When the locking claw that projects and engages with the spring receiving part is provided, the moving space is formed between the locking claw and the spring receiving part when the receiving ring is advanced by the pressing tool, and the engaging space is formed in the moving space. The slider can be moved forward until it hits the pawl, and the slider can be moved to the forward movement position. Furthermore, a pressing piece that abuts the rear end of the retraction spring is formed at the tip of the pressing tool, and a sliding groove is formed on the outer periphery of the slider in which the pressing piece is slidably fitted. If the spring receiving portion is formed around the opening end of the moving groove, the rear end of the retraction spring contacts the tip of the pressing piece and the spring receiving portion when the pushing tool is retracted, and retracts when the pushing tool is advanced. Since the moving space is formed between the spring and the spring receiving portion, the slider can be moved forward to reliably protect the periphery of the core as described above.

Sectional drawing which shows one Example of this invention. 1A and 1B are end views of the writing instrument of FIG. 1 in which a lead-out mechanism is omitted. (A) is an end view of line AA, (B) is an end view of line BB, (C) is an end view of line CC, ( D) is an end view of the line DD. The bottom of the main body is shown, (A) is a side view, (B) is a half sectional view, and (C) is a bottom view. The tip abutment tool is shown, (A) is a plan view, (B) is a half sectional view, (C) is a left side view, and (D) is a right side view. A push tool is shown, (A) is a top view, (B) is a half sectional view, (C) is a left side view. The receiving ring is shown, (A) is a half sectional view, (B) is a left side view, and (C) is a right side view. The half cross-sectional view of a slider. The half cross-sectional view of the lead-out mechanism. Explanatory drawing of a normal writing state. Explanatory drawing when excess writing pressure begins to act. Explanatory drawing which shows the state which the front-end|tip of the core was protected by the slider. Sectional drawing which shows the other Example of a grip part. Sectional drawing which shows another Example of a grip part. FIG. 9 is a partial cross-sectional view showing an embodiment in which a forward spring is not used. Sectional drawing of the Example which does not use a receiving ring. The slider of the Example shown in FIG. 15 is shown, (A) is a left side view, (B) is a front view, (C) is a plan view, (D) is a bottom view. FIG. 15 shows the relationship between the slider and the pusher of the embodiment shown in FIG. 15, (A) is an explanatory diagram for normal writing, (B) is an explanatory diagram for excessive writing pressure, and (C) is a state where the slider is moved. Explanatory drawing. Explanatory drawing which shows another Example. Explanatory drawing which shows another Example. Explanatory drawing which shows the aspect of use.

The present invention can be applied to various kinds of writing instruments, a feeding tool for stick-shaped makeup tools, and the like. In the examples shown in the drawings, an example in which a mechanical pencil is used as a writing instrument will be described. In the present specification, "front" and "tip" mean the direction in which the lead is fed out, and "rear" means the direction in which the lead is retracted. The axial radial direction means a direction orthogonal to the axial center of the barrel body, and the axial length direction means a direction along the axial center.

Referring to FIGS. 1 and 2, a barrel main body 1 includes a main body 2 and a lower body 3 that is connected to the main body 2, and a grip portion 4 is provided on the outer periphery of the lower body to provide a front portion. A taper (base) 5 and a slider 6 projecting from the taper so as to be able to move back and forth are provided in the. As shown in FIGS. 1 and 2, a clip 7 is integrally formed on the main body 2, and a small-diameter inner cylinder portion 9 is formed in the front portion via a screw portion 8. As shown in FIG. 3, the lower part 3 of the main body has a connecting cylinder 11 having a threaded portion 10 on the inner surface at the rear part thereof, and the connecting cylinder 11 is screwed onto the screw part 8 of the upper body 2 to be fixedly connected to the upper body 2. To be done. A front cylinder part 13 having an inner diameter into which the inner cylinder part 9 of the main body 2 is inserted is formed in the front part of the connecting cylinder 11 via a step part 12. An arc-shaped insertion hole 14 and a wall portion 17 having a central hole 16 through which the tip of the lead-out mechanism 15 is inserted are provided near the tip of the front cylindrical portion 13. A long groove 18 extending in the axial direction is provided on the outer periphery of the front tubular portion 13, and a long hole 19 that opens into the front tubular portion 13 is provided at the rear portion of the long groove 18, and the taper 5 is screwed on. The threaded portion 20 is formed, and the locking projection 21 is provided at a position slightly separated from the stepped portion 12 of the connecting cylinder 11 at the rear side.

A tip abutment tool 22 is fitted to the front tube portion 13 so as to be movable in the axial direction. As shown in FIG. 4, the tip end abutment 22 has a head portion 23 having a space portion having an inner diameter into which the outer periphery of the rear end of the taper 5 is inserted. An abutting surface 24 with which the tip abuts is formed, and a sliding piece 25 slidably fitted in the long groove 18 extends to the rear of the head, and a rear cylinder of the lower body 3 of the body is provided at a rear end thereof. A connecting protrusion 26 is provided so as to project into the front cylindrical portion through an elongated hole 19 provided in the portion 13. The contact surface 24 is a cam surface that moves the tip contact member 22 in the axial direction when the grip portion 4 moves in the axial direction or the axial direction. In the embodiment shown in FIG. 4, the contact surface 24 is formed into an inclined surface that spreads forward, and the tip of the grip portion 4 that contacts this inclined surface is formed into a corner portion. It may be formed in the portion, and an inclined surface may be provided at the tip of the grip portion, or the contact surface and the tip of the grip portion may be formed in the inclined surface (not shown).

Further, a ring-shaped rear end abutment tool 27 is fitted between the locking projection 21 of the front tubular part 13 and the step part 12 of the connecting cylinder 11. The surface 28 is formed as an inclined surface that guides the grip portion 4 forward. The grip portion 4 is sandwiched by the front end abutment tool 22 and the rear end abutment tool 27, and normally a space is formed between the grip section 4 and the outer peripheral surface of the front tubular section 13 under the main body 3 by the load of the retraction spring 29. It is retained in the existing hollow state.

A pusher 30 is housed inside the front tube portion 13 of the lower body 3 so as to be movable in the axial direction. As shown in FIG. 5, the pushing tool 30 is formed in a tubular shape, and a pressing piece 31 that is inserted into the insertion hole 14 formed in the wall portion 14 is provided in the front portion in an opposed state. The tip of the pressing piece 31 is in contact with the receiving ring 32, and the retraction spring 29 is provided between the outer step portion (see FIG. 6) 34 of the receiving ring and the inner surface step portion 33 of the taper 5. The retracting spring 29 urges the pushing tool 30, the tip abutting tool 22, and the grip portion 4 rearward. Although the backward movement of the pusher 30 is prevented by engaging the connecting protrusion 26 protruding from the elongated hole 19 at the rear end, the pusher 30 is connected to the connecting protrusion 26 when the tip abutment 22 moves forward. The forward spring 29 can be advanced to compress the reverse spring 29. On the inner front surface of the receiving ring 32, a locking claw 35 that protrudes inward is provided for transmitting a biasing force (load) toward the rear of the retreat spring 29 to the slider 6.

As shown in FIG. 7, the slider 6 is formed in a tubular shape, has a core insertion hole 36 in the front portion, a flange 37 that abuts against the tip surface of the taper 5 on the outer periphery, and an axial length on the outer periphery. A small diameter portion 38 extending in the direction is formed, and a spring receiving portion 39 is formed at the rear end of the small diameter portion 38 so that the locking claw 35 of the receiving ring 32 abuts and the biasing force of the retracting spring 29 acts. There is. Further, as shown in FIG. 9, between the rear end of the slider 6 and the front portion of the lower body 3, that is, the wall portion 17 in the embodiment, an advance spring 40 having a spring force weaker than that of the retreat spring 29 is provided. It is provided. The forward spring 40 urges the slider 6 in the direction in which the spring receiving portion 39 engages with the locking claw 35 of the receiving ring 32, that is, in the forward direction, but the receiving ring 32 is urged in the backward direction by the retreating spring 29. As a result, in a normal writing state, the locking claw 35 contacts the spring receiving portion 39, the slider 6 is biased rearward, and the flange 37 contacts the tip surface of the taper 5. It has stopped.

The lead-out mechanism 15 can be configured in various ways. In the embodiment shown in FIG. 1, as shown in FIG. 8, a core tank 42 is connected to a rear portion of a chuck joint 41, a chuck 43 is connected to a front portion thereof, and a rear end of a clutch 44 for fastening the chuck 43 is a connector. A chuck spring 46 is provided between the connector 45 and the lead tank 42 to urge the chuck 43 and the like rearward. A breaker 48 and a sharp mechanical taper 50 having an inner stepped portion 49 that comes into contact when the clutch 44 moves forward are connected to the front portion of the flange 47 provided on the connector 45. As shown in FIG. 1, a mechanical pressing pipe 51 is inserted into the rear portion of the connector 45, and the mechanical pressing pipe 51 is fixed to the front end of the inner tubular portion 9 of the main body 2 to provide a lead-out mechanism. 15 is mounted on the main body 2 so that the writing pressure at the time of writing is supported on the main body 2. An eraser holder 52 is fitted to the rear portion of the lead tank 42, and an eraser 53 and an eraser cap 54 are attached.

With the above configuration, as shown in FIG. 9, when writing in a standing state, the tip of the grip portion 4 evenly contacts the contact surface 24 of the tip abutment tool 22, and the tip abutment tool is strong. Since the pusher 30 is not pressed and is not advanced, the pusher 30 is retracted by the retracting spring 29. The slider 6 is also retracted by the action of the retracting spring. When an excessive writing pressure is applied to the lead in the direction of arrow 55 in FIG. 1 while the lead 56 is being extended and the barrel is held in an inclined state, the load due to this excess writing pressure is applied to the grip portion. Acting in the axial direction, the grip portion 4 moves in the axial direction as shown in FIG. As a result, the tip abutment tool 22 is pushed and moves forward, and the pushing tool 30 and the receiving ring 32 are moved forward, so that the retracting spring 29 is compressed via the receiving ring 32. As a result, the biasing force that biases the slider 6 rearward disappears, but the receiving ring 32 moves forward, so that the slider 6 can move forward between the spring receiving portion 39 and the locking claw 35 of the receiving ring 32. A moving space S is formed. Then, as shown in FIG. 11, the slider is advanced by the action of the advance spring 40 by the amount of closing this moving space, and covers the tip of the lead 56, so that core breakage can be prevented.

When the grip portion 4 is used in an upright state, when excessive writing pressure acts in the direction of arrow 57 in FIG. 1, the tip abutment tool 22 is pushed by the grip portion 4 and moves in the axial direction. Similarly to FIGS. 10 and 11, the pusher 30 and the receiving ring 32 move forward, the backward spring 29 is compressed, and the slider 6 can move forward. The action of the forward spring 40 advances the slider 6 to move the slider 56 forward. The tip can be protected.

In the above-described embodiment, the tubular grip portion 4 is fitted on the outer periphery of the lower body 3 of the shaft cylinder 1 as the grip portion 4, but the shaft cylinder body may be used as the grip portion. FIG. 12 shows such an embodiment, in which the periphery of a cylindrical main body 58 is covered with a main body cover 59 to form a shaft cylinder main body, and the tip end of the main body cover 59 is brought into contact with the tip abutment tool 22. Similar to the above-described embodiment, the retraction spring 29 urges the main body cover 59 and the tip abutment tool 22 and the like rearward, and the locking projection 60 provided on the main body cover 59 is attached to the flange 61 of the main body 58. By engaging the lower surface, writing can be performed as usual. Other configurations such as the tip abutment tool 22, the push tool 30, the slider 6 and the like are substantially the same as those in the above-described embodiment. With this configuration, when excessive writing pressure acts, the main body cover 59 moves in the axial direction or axial direction, so that the retraction spring 29 is compressed via the tip abutment tool 22 and the pressing tool 30 as in the above embodiment. As a result, the moving space is formed and the slider 6 can be moved forward, and the forward spring 40 can move forward to protect the lead 56.

Further, in the above embodiment, the rear end abutment tool 27 is provided on the rear part of the grip section 4 to hold the upper and lower ends of the grip section 4, but the rear end abutment tool 27 may be omitted. In this case, as shown in FIG. 13, a stopper 62 is provided at the rear end of the grip portion 4, and the stopper 62 hits the stepped portion 12 of the connecting cylinder 11 under the main body 3 so that the tip of the grip portion 4 extends in the axial direction. It suffices to be able to move in the axial direction.

Further, in the above-described embodiment, the slider 6 is biased by the forward spring 40, and when the moving space is generated, the slider 6 is pushed by the forward spring 40 to move forward, but the writing instrument may be used in a standing state. Since there are many sliders, their own weight acts on the slider 6 in the forward direction. Therefore, if the slider 6 has a sufficient weight, the advance spring may be omitted as shown in FIG.

In the above embodiment, the receiving ring 32 that abuts the retreating spring 29 is provided so that the biasing force of the retreating spring 29 indirectly acts on the spring receiving portion 39 of the slider. The slider can be biased rearward by directly acting the spring biasing force on the spring receiving portion.

Referring to FIGS. 15 to 17, the structure is basically similar to that of the embodiment shown in FIG. 1, but since the receiving ring is not used, the pressing piece 31 formed at the tip of the pressing tool 30 is a slider. 6 and extends forward, and abuts the rear end of the retreat spring 29. A flange 63 is formed on the outer periphery of the rear portion of the slider 6, and a sliding groove 64 into which the pressing piece 31 is slidably fitted is formed in the flange 63. The opening end of the sliding groove 64 is formed. The front end surface of the flange 63 around the is a spring receiving portion 65.

With the above configuration, in a normal writing state, the rear end of the retreat spring 29 comes into contact with the tip of the pressing piece 31 to retract the pressing tool 30, and the tip of the pressing piece 31 and the spring receiving portion 65 are substantially flush with each other. The rear end of the retreat spring is in contact with the front end face of the flange 63. As a result, the rear end of the retreat spring 29 comes into direct contact with the slider 6 via the spring receiving portion 65, and the slider 6 is directly pushed by the retreat spring 29, and as shown in FIG. doing. When the pusher 30 moves forward as described above due to excessive writing pressure, the retreat spring 29 is compressed, and the moving space S is formed between the rear end and the spring receiving portion 65 as shown in FIG. 17(B). Since the slider 6 is formed in the same manner as in the above-described embodiment, the slider 6 advances along the moving space S by the advancing spring 40 or the own weight of the slider, as shown in FIG. It can be protected to prevent core breakage. When the excessive writing pressure is removed, the pusher 30 and the slider 6 are retracted by the action of the retracting spring 29, the state returns to the state of FIG. 17(A), and writing can be continued.

In the above-described embodiment, the forward spring 40 has its front end abutting against the rear portion of the slider 6 and its rear end abutting against the wall portion 17 of the lower body 3 to bias the slider 6 in the forward direction. Therefore, when the receiving ring 32 is moved forward by the pressing tool 30 when the writing pressure is excessive, the forward spring 40 may be extended and the load may be weakened. When there is such a possibility, the load of the forward spring may be configured to be constant at all times.

FIG. 18 shows such an embodiment, in which an inwardly projecting inner flange 70 is provided at the rear end of the receiving ring 32, and an advancing spring 40 is provided between the inner flange 70 and the rear portion of the slider 6. There is. By doing so, the load of the advancing spring 40 is always held in a fixed amount, so that when the receiving ring 32 advances, the advancing spring 40 can reliably advance the slider 6.

In the embodiment shown in FIG. 18, the receiving ring 32 is composed of one member, but the receiving ring 32 may be composed of two members. FIG. 19 shows such an embodiment, in which the receiving ring 32 is formed by a tubular front receiving ring piece 71 having a locking claw 35 and a tubular rear receiving ring piece 72 having an inner flange 70. There is. Then, after incorporating the front receiving ring piece 71 into the outer circumference of the slider 6, the forward spring 40 is inserted inside the rear receiving ring piece 72, and the front end of the rear receiving ring piece 72 is inserted into the front receiving ring piece 71. It is fitted on one side and is fixed by a fixing means such as screwing or meshing. By doing so, manufacturing and assembling are easy.

With the above-described configuration, the writing instrument of the present invention, when the axial cylinder is gripped at any angle such as a substantially vertical state or an inclined state, when excessive writing pressure is applied, as shown in FIG. With one mechanism, the slider can be moved forward with the forward spring or the slider's own weight to cover the tip of the lead sufficiently to prevent core breakage, regardless of the excessive writing pressure. There is no damage and there is no risk of impairing the writing feel.

1 Shaft cylinder main body 2 Main body top 3 Main body bottom 4 Grip part 5 Taper 6 Slider 15 Core feeding mechanism 22 Tip contact part 26 Connecting protrusion 27 Rear end contact part 29 Retraction spring 30 Pusher 31 Pressing piece 32 Receiving ring 35 Locking Claws 39, 65 Spring receiving portion 40 Advance spring 51 Mechanical pressing pipe 59 Main body cover S Moving space

The lead-out mechanism 15 can be configured in various ways. In the embodiment shown in FIG. 1, as shown in FIG. 8, a core tank 42 is connected to a rear portion of a chuck joint 41, a chuck 43 is connected to a front portion thereof, and a rear end of a clutch 44 for fastening the chuck 43 is a connector. A chuck spring 46 is provided between the connector 45 and the lead tank 42 to urge the chuck 43 and the like rearward. A breaker 48 and a sharp mechanical taper 50 having an inner stepped portion 49 that abuts when the clutch 44 moves forward are connected to a front portion of a flange 47 provided on the connector 45. As shown in FIG. 1, a mechanical pressing pipe 51 is inserted into the rear portion of the connector 45, and the mechanical pressing pipe 51 is fixed to the front end of the inner tubular portion 9 of the main body 2 to provide a lead-out mechanism. 15 is mounted on the main body 2 so that the writing pressure at the time of writing is supported on the main body 2. An eraser holder 52 is fitted to the rear portion of the lead tank 42, and an eraser 53 and an eraser cap 54 are attached.

With the above configuration, in a normal writing state, the rear end of the retreating spring 29 contacts the tip of the pressing piece 31 to retract the pressing tool 30, and the tip of the pressing piece 31 and the spring receiving portion 65 are substantially flush with each other. The rear end of the retreat spring is in contact with the front end surface of the flange 63. As a result, the rear end of the retreat spring 29 comes into direct contact with the slider 6 via the spring receiving portion 65, and the slider 6 is directly pushed by the retreat spring 29, so that the slider 6 retreats as shown in FIG. doing. When the pusher 30 moves forward as described above due to excessive writing pressure, the retreat spring 29 is compressed, and the moving space S is formed between the rear end and the spring receiving portion 65 as shown in FIG. 17(B). Since it is formed, the slider 6 advances along the moving space S by the advancing spring 40 or the slider's own weight as in the above-described embodiment, and the tip of the lead is sufficiently moved as shown in FIG. 17C. It can be protected to prevent core breakage. When the excessive writing pressure is removed, the pusher 30 and the slider 6 are retracted by the action of the retracting spring 29, the state returns to the state shown in FIG. 17A, and the writing can be continued.

With the above-described configuration, the writing instrument of the present invention has an excessive writing pressure even when the manner of gripping the barrel is any angle such as a substantially vertical state or a tilted state as shown by the solid line and the chain line in FIG. When is applied, the slider can be advanced by the advance spring or the slider's own weight by one mechanism to sufficiently cover the tip of the core and prevent core breakage, regardless of the excessive writing pressure. In addition, the paper surface is not damaged and the writing feeling is not impaired.

Claims (7)

A writing instrument of a type that comprises a taper provided at the tip of the main body and a slider inserted in the taper so as to be movable back and forth, and the core is fed out by a lead feeding mechanism provided in the main body and protected by the slider. A grip part whose tip is movable in the axial direction and the axial direction and is urged by a retreat spring to the rear of the main body, and a tip abutment tool that abuts on the tip of the grip part and can be moved forward by the grip part. And a pusher that moves forward when the tip abutment tool moves forward to compress the retreat spring, and the urging force of the retreat spring acts so that the slider is urged backward by the retreat spring. A moving space is formed between the retreating spring and the spring receiving portion when the retreating spring is compressed by the pusher, and the slider can move forward along the moving space. A writing instrument with a core break prevention mechanism. The writing instrument with a core breaking prevention mechanism according to claim 1, wherein the slider is advanced by an advance spring when the movement space is generated. The writing instrument with a core breakage prevention mechanism according to claim 2, wherein the main body is configured above and below the main body, and a forward spring is provided between a rear portion of the slider and a front portion below the main body. The writing instrument with a core breaking prevention mechanism according to claim 1, wherein when the movement space is generated, the slider advances by the weight of the slider. The slider has a small diameter portion extending in the axial direction, the spring receiving portion is formed at a rear portion of the small diameter portion, a receiving ring is provided between the retreat spring and the pressing tool, and the receiving ring has the small diameter portion. Is provided with a locking claw projecting to the portion and engageable with the spring receiving part, and the moving space is formed between the locking claw and the spring receiving part when the receiving ring is advanced by the pressing tool. The writing instrument with a core breakage prevention mechanism according to claim 1. The lead ring according to claim 5, wherein the receiving ring has an inwardly projecting inward flange at a rear portion thereof, and an advance spring for urging the slider forward is provided between the inward flange and the rear portion of the slider. Writing instrument with a fold prevention mechanism. A pressing piece that abuts the rear end of the retraction spring is formed at the tip of the pressing tool, and a sliding groove that slidably fits the pressing piece is formed on the outer periphery of the slider. The periphery of the opening end of the moving groove serves as the spring receiving portion, the rear end of the retracting spring contacts the tip of the pressing piece and the spring receiving portion when the pressing tool is retracted, and the retracting spring when the pressing tool advances. The writing instrument with a core breaking prevention mechanism according to claim 1, wherein the movement space is formed between the spring receiving portions.

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