Mechanical pencil
The mechanical pencil features a locking mechanism that keeps the slider retracted during transport and ensures immediate writing by controlled extension of the lead, addressing issues of slider movement and inconvenient lead extension in conventional designs.
Patent Information
- Application Number
- JP2021025539
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-02-19
- Publication Date
- 2025-01-06
- Estimated Expiration
- 2041-02-19
AI Technical Summary
Conventional mechanical pencils with retractable sliders face issues where the slider can unintentionally move forward during carrying, and starting to write requires multiple knocks to extend the lead, making it inconvenient.
A mechanical pencil design with a locking mechanism that keeps the slider retracted during carrying and allows immediate writing by advancing the slider with a controlled force, using a guide part, locking parts, and elastic members to ensure the lead protrudes smoothly without additional knocks.
The design prevents unintentional slider movement during transport and allows immediate writing by ensuring the lead extends correctly, enhancing user convenience and reducing mechanical damage.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to a mechanical pencil having a slider that can be retracted into a barrel. [Background technology]
[0002] Conventionally, mechanical pencils have been configured so that a slider stored within a barrel so as to be able to move back and forth protrudes forward from the front opening of the barrel when writing, and can be retracted into the barrel together with the writing lead when carried. These pencils have the advantage that when writing, the writing lead protrudes from the front end of the thin slider, making it easy to see the lead and making writing very easy. Furthermore, because the front end of the thin slider can be retracted into the barrel, the front end of the slider will not come into contact with other objects and be broken, or damage other objects, when carried, and these pencils have actually received high praise in the marketplace.
[0003] Patent Document 1 discloses a slider structure for a mechanical pencil in which the lead guide of the slider engages at positions protruding and retracted from the tip component, and the lead guide is fixed in a position protruding from the tip component when writing, and can be maintained in a retracted state within the tip component when not in use. The slider structure in Patent Document 1 comprises a slider to which the lead guide is fixed, a sliding piece that slides on the inner surface of the tip tool, and a protrusion on the outer surface of the rear end of this sliding piece. The inner surface of the tip tool has a groove into which the protrusion engages at the position where the lead guide protrudes and retracts from the hole at the tip of the tip tool. The slider's forward and backward movement can be fixed by engaging the protrusion of the slider with the groove of the tip tool. As a result, even if the mechanical pencil is subjected to vibrations when carried around, the slider will not move forward and the slider can be maintained in a retracted state, making it very convenient.
[0004] However, in the structure of Patent Document 1, when the slider is advanced from a retracted state to cause the lead guide to protrude from the leading tool, the amount of advancement of the lead is set to be smaller than the amount of advancement of the slider, which presents an issue in that, in order to start writing, it is necessary to protrude the lead guide and then perform multiple knocking operations to cause the lead to protrude from the front end of the lead guide. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 5-12184 Summary of the Invention [Problem to be solved by the invention]
[0006] The present invention has been made based on the above background, and its object is to provide a mechanical pencil which allows the slider to be locked in a retracted state within the barrel so that it does not move forward when carried, and which allows the lead to protrude from the front end of the slider when the slider is moved forward from the retracted state when writing, thereby allowing writing to be started immediately. [Means for solving the problem]
[0007] The present invention comprises a barrel having a barrel body and a tip member disposed in front of the barrel, a slider contained in the tip member and attached so as to be movable back and forth relative to the tip member, a chuck disposed within the barrel and gripping a writing lead, a cylindrical body disposed outside the chuck, and a tightening portion that tightens the chuck inside the cylindrical body, The slider has a guide portion having an inner hole for guiding the core at the front and a holding portion for holding the core with a constant force, The guide portion protrudes forward from the front end opening of the tip member when writing, and is retractable into the barrel together with the lead when carried, in a mechanical pencil, Behind the cylindrical body, an intermediate gripping member that can slide back and forth along the axial direction with respect to the cylindrical body is disposed. The intermediate gripping member has a gripping portion that grips the cylindrical body, a first abutting portion that abuts against the chuck to restrict forward movement of the chuck, and a second abutting portion that abuts against the cylindrical body to restrict forward movement of the cylindrical body with respect to the cylindrical body. At the front of the cylindrical body, it has a slider pressing portion that abuts against the rear portion of the slider. Behind the intermediate gripping member, it has an operating body that can operate the intermediate gripping member in the front-rear direction. On the outer peripheral portion of the slider, it has a locking portion that locks with a locked portion formed on the inner peripheral portion of the tip member when the slider retracts. An elastic member that biases the slider forward is stretched between the slider and the tip member. In order to release the locked state between the locking portion and the locked portion The minimum required When the pressing force for pressing the slider forward along the axial direction is X, and the intermediate gripping member grips the cylindrical body As a result, a frictional force is generated between the intermediate gripping member and the cylindrical body. is Y, it satisfies the relational expression Y < X. From the state where the guide portion retracts into the shaft cylinder and the locking portion and the locked portion are locked, the slider is advanced by operating the operating body, and when the guide portion protrudes forward from the front end opening of the tip member, the forward movement amount of the slider is S1 and the forward movement amount of the core is S2, it is a sharp pencil characterized in that S1 < S2. In the present invention, the side where the front end opening of the shaft cylinder is located is expressed as the front, and the opposite direction is expressed as the rear. Also, the direction toward the axis of the shaft cylinder is expressed as the inner side, and the opposite direction is expressed as the outer side.
[0008] According to the present invention, by retracting the guide portion into the shaft cylinder and engaging the engaging portion and the engaged portion, it is possible to prevent the slider from advancing contrary to intention due to vibrations during carrying or the like. Further, when the slider is advanced by operating the operating body from the state where the slider is retracted and locked in the shaft cylinder and the guide portion is projected forward from the front end opening of the front member, and the forward movement amount of the slider is S1 and the forward movement amount of the core is S2, since the relational expression of S1 < S2 is satisfied, if the front end of the core is at substantially the same position as the front end of the guide portion of the slider when the slider is retracted into the shaft cylinder, when the slider is advanced and the guide portion is projected from the shaft cylinder, the core projects from the guide portion, so that there is an excellent effect that writing can be started immediately without further knocking operation. In addition, the slider pressing portion of the cylindrical body in the present invention may be integrally formed with the cylindrical body, or a plurality of components may be fixed by means such as press fitting, locking fitting, or adhesion.
[0009] Furthermore, in order to release the locked state between the locking portion and the locked portion by pressing the slider forward along the axial direction The minimum required When the pressing force is X and the intermediate gripping member grips the cylindrical body This generates a friction force between the intermediate gripping member and the cylindrical body. is Y, since the relational expression of Y < X is satisfied, when the intermediate gripping member advances, the intermediate gripping member can advance until the second contact portion of the intermediate gripping member contacts the cylindrical body even when contacting the slider pressing portion of the cylindrical body gripped by the intermediate gripping member. Therefore, the chuck can be advanced with respect to the cylindrical body by bringing the first contact portion of the intermediate gripping member and the chuck into contact first.
[0010] Also, in a state where the guide portion is retracted into the shaft cylinder and the locking portion and the locked portion are locked, a gap may be formed between the rear end of the slider and the slider pressing portion. In this case, by operating the operating body to advance the intermediate gripping member, the cylindrical body can be advanced by the gap with respect to the slider together with the chuck gripping the core.
[0011] In addition, a tightening portion may be provided on the inner surface of the cylindrical body. In this case, when the chuck advances relative to the cylindrical body, the chuck also advances relative to the tightening portion, thereby releasing the tightening of the chuck by the tightening portion and releasing the grip on the lead.
[0012] In addition, a fastener that can slide back and forth relative to the cylindrical body may be disposed inside the cylindrical body, and a fastening portion may be provided on the inner peripheral surface of the fastener, in which case, even if the forward movement of the cylindrical body stops when the operating body is operated to advance the cylindrical body, the chuck can advance together with the fastener relative to the cylindrical body, so that the amount of protrusion of the core can be increased by the amount of movement of the fastener. Therefore, even if it is structurally difficult to form a sufficient length of the gap between the rear end of the slider and the slider pressing portion, the core can be advanced by the amount of movement of the fastener relative to the slider.
[0013] The locking portion of the slider may have a protruding portion that protrudes outward, and the locked portion of the tip member may have a recessed portion that recesses outward, in which case the locking can be achieved by fitting the protruding portion over the recessed portion, thereby firmly locking the slider and tip member together, thereby preventing the locking between the slider and tip member from being released due to vibrations during carrying, etc. The recessed portion of the tip member may be formed integrally with the tip member, or may be formed separately and fixed by engagement, screwing, press-fitting, adhesion, etc.
[0014] The protrusion may also be configured with an O-ring made of an elastic material, in which case the O-ring is preferably used because it is less likely to wear out due to deformation or abrasion even if the protrusion and recess are repeatedly engaged and disengaged because the O-ring elastically deforms when engaged. The elastic material for the O-ring may be synthetic rubber, silicone rubber, nitrile rubber, fluororubber, or the like.
[0015] The mechanical pencil of the present invention may have a tip knock structure in which the lead is advanced forward by the backward and forward movements of the slider when writing. In this case, the front end of the slider comes into contact with the paper and moves slightly backward, automatically advancing the lead when writing, which is preferable because it minimizes knocking movements from the start to the end of use and allows for comfortable continuous writing. Effect of the Invention
[0016] According to the present invention, a mechanical pencil can be provided in which the slider can be locked in a retracted state within the barrel so that the slider does not move forward when the pencil is carried, and when the slider is moved forward from the locked state, the lead protrudes from the front end of the slider, allowing writing to be started immediately. [Brief description of the drawings]
[0017] [Figure 1] 1 is a vertical cross-sectional view showing a mechanical pencil according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged longitudinal sectional view of a main part of the mechanical pencil of FIG. 1. [Diagram 3] FIG. 3 is an end view showing the AA end face of FIG. 2. [Figure 4] 3 is a vertical cross-sectional view showing a state in which the slider is retracted in the mechanical pencil of FIG. 2. FIG. [Diagram 5] 5 is a vertical cross-sectional view showing a state in which the intermediate gripping member has advanced from the state shown in FIG. 4 and the chuck has come into contact with a first contact portion. [Figure 6] 6 is a vertical cross-sectional view showing a state in which the intermediate gripping member has advanced further from the state shown in FIG. 5 and the cylindrical body has come into contact with the second contact portion. [Figure 7] 7 is a vertical cross-sectional view showing a state in which the intermediate gripping member has further advanced from the state shown in FIG. 6 and the locked state between the slider and the tip member has been released. [Figure 8] 8 is a vertical cross-sectional view showing a state in which the slider has advanced from the state shown in FIG. 7. [Figure 9] FIG. 11 is a longitudinal sectional view showing a mechanical pencil according to a second embodiment of the present invention. [Figure 10] FIG. 10 is an enlarged longitudinal sectional view of a main part of the mechanical pencil of FIG. 9. [Figure 11] 11 is a vertical cross-sectional view showing a state in which the slider is retracted in the mechanical pencil of FIG. 10. FIG. [Figure 12] 12 is a vertical cross-sectional view showing a state in which the intermediate gripping member has advanced from the state shown in FIG. 11 and the chuck has come into contact with a first contact portion. [Figure 13] 13 is a vertical cross-sectional view showing a state in which the intermediate gripping member has further advanced from the state shown in FIG. 12 and the fastener has come into contact with the second contact portion. [Figure 14] 14 is a vertical cross-sectional view showing a state in which the intermediate gripping member has further advanced from the state shown in FIG. 13 and the locked state between the slider and the tip member has been released. [Figure 15] 15 is a vertical cross-sectional view showing a state in which the slider has advanced from the state shown in FIG. 14 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0019] First embodiment FIG. 1 is a longitudinal cross-sectional view of a mechanical pencil 1 in a first embodiment of the present invention, FIG. 2 is an enlarged longitudinal cross-sectional view of a main portion of FIG. 1, FIG. 3 is an enlarged end view of the AA end face of FIG. 2, FIG. 4 is a longitudinal cross-sectional view of the mechanical pencil of FIG. 2 in a state where the slider has retracted, FIG. 5 is a longitudinal cross-sectional view of a state where the intermediate gripping member has advanced from the state of FIG. 4 and the chuck has come into contact with the first abutment portion, FIG. 6 is a longitudinal cross-sectional view of a state where the intermediate gripping member has advanced further from the state of FIG. 5 and the cylindrical body has come into contact with the second abutment portion, FIG. 7 is a longitudinal cross-sectional view of a state where the intermediate gripping member has advanced further from the state of FIG. 6 and the locked state between the slider and the tip member has been released, and FIG. 8 is a longitudinal cross-sectional view of a state where the slider has advanced from the state of FIG. 7.
[0020] As shown in Figures 1 to 3, a mechanical pencil 1 has a barrel 2 composed of a tip member 21, a connecting body 22 screwed to the rear of the tip member 21, and a barrel body 23 screwed to the rear of the connecting body 22. The mechanical pencil 1 is also composed of a slider 3 inserted inside the barrel 2 so as to be slidable in the front-to-rear direction relative to the barrel 2, a lead-advancing mechanism 4 arranged behind the slider 3 and capable of sliding in the front-to-rear direction, an intermediate gripping member 5 arranged behind the lead-advancing mechanism 4 and capable of sliding in the front-to-rear direction, and an operating body 6 arranged behind the intermediate gripping member and protruding rearward from the rear end opening of the barrel 2.
[0021] The tip member 21 is composed of a tip member body 211 and an inner piece 212 press-fitted into the rear inner periphery of the tip member body 211. The front inner periphery has a front end opening 21a from which the slider 3 appears and disappears, the central inner periphery has a recess 21b recessed outward as a locked portion that locks with a locking portion of the slider 3 described later, and the rear inner periphery has a step portion 21c. The recess 21b (locked portion) is formed in the front portion 212a of the inner piece 212, and a gap is formed between the front portion 212a and the inner periphery of the tip member body 211, so that when a protrusion 3e serving as a locking portion of the slider 3 described later locks with the recess 21b (locked portion), the front portion 212a bends outward, making it easier to lock. The front portion 212a may be divided into multiple portions along the circumferential direction so as to be easily bent.
[0022] The slider 3 is disposed inside the tip member 21 so as to be slidable back and forth along the axial direction. The slider 3 is composed of a slider body 31, an O-ring 32 fitted on the outer circumferential concave portion of the slider body 31, and a lead holding member 33 press-fitted into the inner circumferential portion of the slider body 31. The slider 3 also has a guide portion 3a through which the writing lead 7 is inserted in the inner circumferential portion, a step portion 3b formed on the outer circumferential portion, a rear abutment portion 3c at the rear end of the slider 3 that abuts against the slider pressing portion 42c of the cylindrical body 42, a lead holding portion 3d that holds the lead 5 with a weak force, and a protrusion portion 3e formed of the O-ring 32 that protrudes outward from the outer circumferential portion and serves as a locking portion that locks into the recess 21b (locked portion). A coil spring 8, which is an elastic member, is stretched between the step portion 3b of the slider 3 and the step portion 21c of the tip member 21, and the slider 3 is always resiliently urged forward with respect to the tip member 21.
[0023] The O-ring 32 and the lead holding member 33 are formed from an elastic material. Specifically, synthetic rubber, silicone rubber, nitrile rubber, fluororubber, etc. can be used for the O-ring 32, and synthetic rubber, silicone rubber, nitrile rubber, fluororubber, etc. can be used for the lead holding member 33. In this embodiment, the holding force that holds the lead 7 by the lead holding part 3d is set to about 0.3 N.
[0024] The barrel body 23 is made up of a front shaft 231 and a rear shaft 232 that is screwed to the rear of the front shaft 231. The inner periphery of the barrel body 23 has a front step 23a formed in a stepped shape on the front inner periphery and an inner step 23b that protrudes inward on the central outer periphery.
[0025] A lead-advancing mechanism 4 is arranged behind the slider 3 and on the inner circumference of the shaft tube 2, and is composed of a chuck 41, a cylindrical body 42 fitted around the outside of the chuck 41, a steel ball 43 arranged between the chuck 41 and the cylindrical body 42, and a coil spring 44 that is stretched between the central inner section 42a of the cylindrical body 42 and the rear section 41c of the chuck 41 and springs the chuck 41 forward.
[0026] The chuck 41 has a chuck body 411 and a rear cylindrical body 412 press-fitted to the rear of the chuck body 411, and is configured to be movable back and forth relative to the cylindrical body 42. The head 41a of the chuck 41 is divided into two along the axial direction, and each divided head 41a is formed so as to gradually move away from each other toward the front, and is configured so that the heads 41a can grip the lead 7 by bending radially inward. The head 41a also has a chuck recess 41b into which a steel ball 43 is inserted, and a stepped rear step 41c at the rear.
[0027] The cylindrical body 42 has a cylindrical body main body 421 and a front abutment member 422 press-fitted into a front inner hole of the cylindrical body main body 421, has an inner hole penetrating in the front-rear direction, and is configured to be slidable along the axial direction relative to the barrel 2. A fastening portion 42b is formed at the front of the inner hole as an inclined portion expanding in diameter toward the front, and the fastening portion 42b is disposed so as to abut against the steel ball 10 inserted into the chuck recess 41b of the chuck 41, and has a central inner step 42a at the center of the inner hole. An outer step 42d formed in a stepped shape is formed on the outer periphery of the cylindrical body 42, and the outer step 42d abuts against the front step 23a of the barrel body 23, thereby restricting the backward movement of the cylindrical body 42. In addition, the front end of the cylindrical body 42 is provided with a slider pressing portion 42c that abuts against the rear abutment portion 3c of the slider 3, and the slider pressing portion 42c abuts against the rear end of the inner link 212 of the tip member 21, thereby restricting its forward movement.
[0028] The lead feeding mechanism 4 of this embodiment has a known ball chuck structure in which a ball is disposed between the chuck and the tightening portion, and the chuck 41 is resilient backward by the elastic force of the coil spring 44. When the chuck 41 is gripping the lead 7, a wedge action is generated by the tightening portion 42b of the cylindrical body 42 via the steel ball 43 as the chuck 41 retreats, and the lead 7 can be gripped by the chuck 41. In addition, a feature of the ball chuck structure is that when a backward pressing force (writing pressure) is applied to the lead 7, the chuck 41 strongly grips the lead 7, restricting the retreat of the lead 7, but when a forward pulling force is applied to the lead 7, the wedge action is immediately released, allowing the lead 7 to move forward. In this embodiment, when the slider 3 advances while the lead 7 is held by the lead holding portion 3d of the slider 3, the lead 7 also advances in accordance with the advance of the slider 3.
[0029] The intermediate gripping member 5 is composed of a gripping member main body 51 and a rear cylinder 52 press-fitted to the rear of the gripping member main body 51, and is housed inside the barrel 2 so as to be slidable along the axial direction. The front part of the intermediate gripping member 5 is divided into four parts evenly along the circumferential direction (see FIG. 3), and has a gripping part 42a that grips the cylindrical body 42 with a certain force by elastic force, and a core storage part 5b in the rear inner peripheral part has a core storage part 5b in which a plurality of spare cores are stored. A coil spring 9 is stretched between the front end of the rear cylinder 52 and the inner step part 23d of the barrel main body 23, and the intermediate gripping member 5 is always resilient backward by the elastic force of the coil spring 9. Furthermore, the central inner step of the intermediate gripping member 5 has a first abutment part 5c that abuts against the rear end of the chuck 41 when the intermediate gripping member 5 advances, and a second abutment part 5d that abuts against the rear end of the cylindrical body 42. In this embodiment, the first contact portion 5c and the second contact portion 5d are formed on the same plane on the inner side and the outer side, respectively, to improve workability. The intermediate gripping member 5 has a central outer step on the outer periphery, and the inner step portion 23b of the barrel body 23 abuts against the central outer step, thereby restricting rearward movement.
[0030] An operating body 6 is detachably attached to the rear portion of the intermediate gripping member 5, and is configured such that by pressing the operating body 6 forward, the intermediate gripping member 5 can be pressed forward.
[0031] Here, the relationship between the pressing force for releasing the locked state between the slider 3 and the front member 21 and the gripping force with which the gripping portion 5a of the intermediate gripping member 5 grips the cylindrical body 42 will be described in detail. As shown in FIG. 4, in a state where the protruding portion 3e (locking portion) of the slider 3 and the concave portion 21b (locked portion) of the front member 21 are locked, when the slider 3 is pressed forward along the axial direction by the cylindrical body 42 to release the locked state The minimum required Let the pressing force be X, and the gripping portion 5a of the intermediate gripping member 5 grips the cylindrical body 42 As a result, a frictional force is generated between the intermediate gripping member 5 and the cylindrical body 42. Let it be Y. It is configured to satisfy the relational expression of Y < X. Specifically, in the present embodiment, the pressing force X is about 2 N, friction force Y is about 1 N, and the above relational expression is satisfied.
[0032] Next, in the present embodiment, a state in which the core 7 is fed forward by a knocking operation of pressing the operating body 6 forward from the states of FIGS. 1 and 2 will be described. 1 and 2, when the operating body 6 is pressed forward against the elastic force of the coil spring 9, the intermediate gripping member 5 pressed by the operating body 6 also moves forward at the same time. Then, when the intermediate gripping member 5 moves forward, the cylindrical body 42 held by the gripping portion 5a of the intermediate gripping member 5 moves forward together with the chuck 41 and the lead 7. At this time, the front end of the lead 7 protrudes from the front end of the guide portion 3a of the slider 3. Then, when the slider pressing portion 42c of the cylindrical body 42 abuts against the rear end of the inner piece 212 of the tip member 21 to stop the forward movement of the cylindrical body 42, the forward movement of the chuck 41 and the lead 7 held by the chuck 41 also stops at the same time. When the pressure on the operating body 6 is released in this state, the intermediate gripping member 5 and the operating body 6 move backward by the elastic force of the coil spring 9, and the cylindrical body 42 held by the gripping portion 5a of the intermediate gripping member 5 moves backward. At this time, the lead 7 is held by the lead holding portion 3d of the slider 3, and as the cylindrical body 42 and the chuck 41 move backward, a forward tensile force is applied to the lead 7. As described above, since a ball chuck structure is used in this embodiment, when a forward tensile force is applied to the lead 7, the wedge action of the tightening portion 42b on the chuck 41 is immediately released, allowing the lead 7 to move forward, so the lead 7 maintains its forward position without moving backward, and as a result, the lead 7 is advanced forward relative to the slider 3.
[0033] Next, a state in which the tip knock structure is activated and the lead 7 is advanced forward in conjunction with the writing action when writing with this embodiment will be described. 1 and 2, writing is performed on a paper surface or the like, and when the front end of the lead 7 wears, the front end of the slider 3 comes into contact with the paper surface during writing. When the slider 3 comes into contact with the paper surface, the slider 3, which is pressed against the paper surface, retreats relative to the tip member 21 (shaft tube 2) against the elastic force of the coil spring 8, and the lead 7 is held by the chuck 41. As described above, the lead advancing mechanism 4 of this embodiment strongly grips the lead 7 when the lead 7 is pressed backward, so the lead 7 does not retreat, and only the slider 3 retreats relative to the tip member 21 and the lead 7. Here, when the front end of the slider 3 leaves the paper surface, the slider 3 advances due to the elastic force of the coil spring 8, but at this time, since the lead 7 is held by the lead holding portion 3d of the slider 3, a forward pulling force is applied to the lead 7, and the wedge force of the tightening portion 42d on the chuck 41 decreases, and the lead 7 is released from the chuck 41, just as when the lead is advanced. For this reason, as the slider 3 advances, the lead 7 held by the slider 3 also advances, forming a tip knock structure in which the lead is automatically advanced forward as the user writes.
[0034] Next, the state in which the slider 3 and the lead 7 are retracted from the state shown in FIG. 1 and FIG. 2 and are engaged with the tip member will be described with reference to FIG. 1 to FIG. When the operating body 6 is pressed forward from the state of Fig. 1 and Fig. 2 to the state of Fig. 8, the intermediate gripping member 5 is pressed and moves forward, and further, as the intermediate gripping member 5 moves forward, the chuck 41 moves forward relative to the cylindrical body 42, so that the wedge action of the tightening part 42b on the chuck 41 decreases and the chuck 41 releases the lead 7. When the slider 3 and the lead 7 are pressed against a flat surface such as a desk in the state of Fig. 8, the lead 7 first moves back to the front end of the slider 3, and then the slider 3 and the lead 7 move back relative to the tip member 21 (shaft tube 2), and the protruding part 3e (locking part) of the slider 3 and the recessed part 21b (locked part) of the tip member 21 are locked. Then, when the forward pressure on the operating body 6 is released, the chuck 41, the cylindrical body 42, the intermediate gripping member 5, and the operating body 6 move backward by the elastic forces of the coil springs 9 and 44, and the lead 7 is again locked by the chuck 41, resulting in the state of Fig. 4. In the state shown in FIG. 4, the front end of the lead 7 is at approximately the same position as the front end of the slider 3, and a gap L is formed between the rear abutment portion 3c of the slider 3 and the slider pressing portion 42c of the cylindrical body 42. By setting the mechanical pencil 1 in the state shown in FIG. 4, even if the mechanical pencil 1 is carried around in a pencil case or a pocket of a garment, the tip of the slider 3 will not be damaged by vibration or contact with other objects, and at the same time, the thin tip of the slider 3 will not scratch other objects. Furthermore, as described above, the mechanical pencil 1 of this embodiment has a tip knock structure that allows the lead 7 to be advanced forward by the retraction and advancement of the slider 3, so that by locking the slider 3, the lead 7 can be prevented from being unintentionally advanced forward when carried. Furthermore, since the protruding portion 3e is made of an O-ring 32 made of rubber such as silicone rubber, it is possible to prevent wear due to deformation, wear, etc., even if the protruding portion 3e and the recessed portion 21b are repeatedly engaged and disengaged.
[0035] Next, an operation of releasing the locked state between the slider 3 and the tip member 21 by pressing the operation body 6 forward from the state shown in FIG. 4 to return to the writing state will be described. When the operating body 6 is pressed forward from the state shown in FIG. 4, the intermediate gripping member 5 pressed by the operating body 6 advances. When the intermediate gripping member 5 advances, the cylindrical body 42 held by the gripping portion 5a of the intermediate gripping member 5 advances together with the chuck 41 by the gap L until the rear abutment portion 3c of the slider 3 abuts against the slider pressing portion 42c of the cylindrical body 42. At this time, the lead 7 held by the chuck 41 also advances relative to the slider 3 by the gap L, and the lead 7 protrudes forward from the front end of the guide portion 3a of the slider 3 by the gap L. Specifically, in this embodiment, the gap L is set to 0.3 mm to 0.5 mm, so that the length by which the lead 7 protrudes from the front end of the guide portion 3a of the slider 3 is also 0.3 mm to 0.5 mm. When the rear contact portion 3c of the slider 3 comes into contact with the slider pressing portion 42c of the cylindrical body 42, the slider 3 and the tip member 21 are released from the locked state as described above. The minimum required Pressing force X and the gripping portion 5a of the intermediate gripping member 5 grip the cylindrical body 42. As a result, a frictional force is generated between the intermediate gripping member 5 and the cylindrical body 42.Since the relationship of Y satisfies the relational expression of Y < X, the forward movement of the cylindrical body 42 stops, and the gripping portion 5a of the intermediate gripping member 5 moves forward along the outer surface of the cylindrical body 42 in a sliding manner, and the first contact portion 5c of the intermediate gripping member 5 and the rear end of the chuck 41 come into contact with each other, reaching the state shown in FIG. 5. Then, when the operating body 6 is further pressed and the intermediate gripping member 5 moves forward, the chuck 41 moves forward with respect to the cylindrical body 42 against the elastic force of the coil spring 44, and the wedging action on the chuck 41 by the clamping portion 42b via the steel ball 43 decreases, and the core 7 is released from the chuck without moving forward. The forward movement of the chuck 41 stops when the rear end of the cylindrical body 42 and the second contact portion 5d of the intermediate gripping member 5 come into contact with each other, reaching the state shown in FIG. 6. Then, when the intermediate distribution member 6 further moves forward from the state shown in FIG. 6, the slider pressing portion 42c of the cylindrical body 42 presses the slider 3, and the locking state between the protruding portion 3e (locking portion) of the slider 3 and the concave portion 21b (locked portion) of the front member 21 is released, reaching the state shown in FIG. 7. When the locking state between the slider 3 and the front member 21 is released, the guide portion 3a of the slider 3 moves forward by the elastic force of the coil spring 8 and protrudes forward from the front end opening 21a of the front member 21, and the core 7 held by the core holding portion 3d also moves forward while maintaining the positional relationship in the axial direction with the slider 3, reaching the state shown in FIG. 8. Here, when the pressing state of the operating body 6 is released, the intermediate gripping member 5, the cylindrical body 42, and the chuck 41 retreat by the elastic force of the coil spring 9 and the elastic force of the coil spring 44 and return to their original positions, reaching the states shown in FIGS. 1 and 2.
[0036] By the pressing operation of the operation body 6 to release the locked state between the slider 3 and the tip member 21, in the state of FIG. 4, the front end of the slider 3 and the front end of the core 7 were substantially at the same position in the axial direction, but at the end of the operation, it protrudes forward by a gap L in the length of FIG. 5. That is, in the present embodiment, by operating the operation unit 6 from the locked state between the slider 3 and the tip member 21, the slider 3 is advanced. When the forward movement amount of the slider 3 when the guide portion 3a protrudes forward from the front end opening 21a of the tip member 21 is S1 and the forward movement amount of the core 7 is S2, since S2 is longer by the gap L, the relational expression S1 < S2 is satisfied. For this reason, if the front end of the core 7 is substantially at the same position as the front end of the guide portion 3a of the slider 3 when the slider 3 retracts into the tip member 21 (shaft cylinder 2), when the slider 3 is advanced and the guide portion 3a protrudes from the tip member 21 (shaft cylinder 2), the core 7 protrudes by the gap L from the guide portion 3a. Therefore, there is an excellent effect that writing can be started immediately without further knocking operation.
[0037] (Second Embodiment) FIG. 9 is a longitudinal sectional view of the mechanical pencil 11 in the second embodiment of the present invention, FIG. 10 is an enlarged longitudinal sectional view of the main part of FIG. 9, FIG. 11 is a longitudinal sectional view showing a state where the slider has retracted in the mechanical pencil of FIG. 10, FIG. 12 is a longitudinal sectional view showing a state where the intermediate gripping member has advanced and the chuck and the first contact portion are in contact from the state of FIG. 11, FIG. 13 is a longitudinal sectional view showing a state where the intermediate gripping member has further advanced and the fastener and the second contact portion are in contact from the state of FIG. 12, FIG. 14 is a longitudinal sectional view showing a state where the intermediate gripping member has further advanced and the locked state between the slider and the tip member has been released from the state of FIG. 13, and FIG. 15 is a longitudinal sectional view showing a state where the slider has advanced from the state of FIG. 14. Also, parts having the same structure as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0038] The lead-advancing mechanism 14 of the mechanical pencil 11 of this embodiment is composed of a chuck 141, a cylindrical body 142 fitted around the outside of the chuck 141, a fastener 145 disposed between the chuck 141 and the cylindrical body 142 and arranged so as to be slidable along the axial direction relative to the cylindrical body 142, and a coil spring 44 that is stretched between a central inner section 142a of the cylindrical body 142 and a rear section 141c of the chuck 141 to constantly spring the chuck 141 forward.
[0039] The chuck 141 has a chuck body 1411 and a rear cylindrical body 412 press-fitted to the rear of the chuck body 1411, and is configured to be movable back and forth relative to the cylindrical body 142. The head 141a of the chuck 141 is divided into two parts along the axial direction, and each divided head 141a is formed so as to gradually move away from each other toward the front, and each head 141a is configured to be bent radially inward to be able to grip the lead 7.
[0040] The cylindrical body 142 has a cylindrical body main body 1421 and a front abutment member 422 press-fitted into a front inner hole of the cylindrical body main body 1421, has an inner hole penetrating in the front-rear direction, and is configured to be slidable along the axial direction relative to the shaft cylinder 2. A fastener 145 having a fastening portion 145a formed on its inner periphery for fastening the head 141a of the chuck 141 is disposed in the front of the inner hole of the cylindrical body 142 so as to be slidable along the axial direction, and a central inner step 142a against which the front end of the coil spring 44 abuts is provided in the center of the inner hole. Furthermore, the front end of the cylindrical body 142 has a slider pressing portion 142c that abuts against the rear abutment portion 3c of the slider 3, and the slider pressing portion 142c abuts against the rear end of the inner piece 212 of the tip member 21, thereby restricting forward movement. The outer periphery has an outer step 142d formed in a stepped shape, and the outer step 142d abuts against the front step 23a of the barrel main body 23, thereby restricting the rearward movement of the tubular body 142. The amount of movement M (see FIG. 11) that the fastener 145 can move in the axial direction is restricted by the front end of the fastener 145 abutting against the retreating front abutment member 422.
[0041] Next, the operation of this embodiment will be described with reference to FIGS. 9 and 10, the operating body 6 is pressed forward to the state of FIG. 15, the intermediate gripping member 5 is pressed and moves forward, and further, as the intermediate gripping member 5 moves forward, the chuck 141 moves forward relative to the cylindrical body 142, and the fastening portion 145a of the fastener 145 is released from the head 141a of the chuck 141, the wedge action on the chuck 141 is reduced, and the chuck 141 releases the lead 7. In this state of FIG. 15, when the slider 3 and the lead 7 are pressed against a flat surface such as a desk, the lead 7 first moves back to the front end of the slider 3, and then the slider 3 and the lead 7 simultaneously move back relative to the tip member 21 (shaft tube 2), and the protruding portion 3e (locking portion) of the slider 3 and the recessed portion 21b (locked portion) of the tip member 21 are locked, resulting in the state of FIG. 11. Therefore, in the state of FIG. 11, the front end of the lead 7 is approximately in the same position as the front end of the slider 3. In this embodiment, the rear contact portion 3c of the slider 3 and the slider pressing portion 142c of the cylindrical body 142 are configured to come into contact with each other at this time.
[0042] Next, an operation of releasing the locked state between the slider 3 and the tip member 21 and returning to the writing state by pressing the operation body 6 forward from the state shown in FIG. 11 will be described. 11, when the operating body 6 is pressed forward, the intermediate gripping member 5 pushed by the operating body 6 advances. When the intermediate gripping member 5 advances, the rear contact portion 3c and the slider pressing portion 142c come into contact with each other. Furthermore, in order to release the locked state between the slider 3 and the tip member 21, The minimum required Pressing force X causes the gripping portion 5a of the intermediate gripping member 5 to grip the cylindrical body 142. As a result, a frictional force is generated between the intermediate gripping member 5 and the cylindrical body 142.Since the relationship of Y satisfies the relational expression of Y < X as in the first embodiment, the cylindrical body 142 does not move forward, and the gripping portion 5a of the intermediate gripping member 5 moves forward with respect to the cylindrical body 142 so as to slide on the outer surface of the cylindrical body 142, and the first contact portion 5c of the intermediate gripping member 5 and the rear end of the chuck 141 come into contact with each other to reach the state shown in FIG. 12. Then, when the operating body 6 is further pressed and the intermediate gripping member 5 moves forward, the chuck 141 and the tightening tool 145 move forward with respect to the cylindrical body 142 against the elastic force of the coil spring 44, and the core 7 gripped by the chuck 141 also moves forward simultaneously by the wedging force of the tightening tool 145. The forward movement of the core 7 causes the front end of the tightening tool 145 and the rear end of the front contact member 422 to come into contact with each other, and the head portion 141a of the chuck 141 and the tightening portion 145a of the tightening tool 145 to separate from each other, so that the chuck 141 releases the core 7 and stops, reaching the state shown in FIG. 13. At this time, the forward movement amount of the core 7 with respect to the slider 3 in this embodiment is substantially equal to the movement amount M (see FIG. 11) of the tightening tool 145, and the core 7 protrudes forward by the movement amount M from the front end of the guide portion 3a of the slider 3. Specifically, in this embodiment, since the movement amount M of the tightening tool 145 is set to 0.3 mm, the length by which the core 7 protrudes from the front end of the guide portion 3a of the slider 3 is also 0.3 mm. Then, when the intermediate distribution member 6 further moves forward from the state shown in FIG. 13, the slider pressing portion 142c of the cylindrical body 142 presses the rear contact portion 3c of the slider 3, and the locking state between the protruding portion 3e (locking portion) of the slider 3 and the concave portion 21b (locked portion) of the front member 21 is released, reaching the state shown in FIG. 14. When the locking state between the slider 3 and the front member 21 is released, the guide portion 3a of the slider 3 protrudes forward from the front end opening 21a of the front member 3 advanced by the elastic force of the coil spring 8, and the core 7 held by the core holding portion 3d also moves forward while maintaining the positional relationship in the axial direction with the slider 3, reaching the state shown in FIG. 15. Here, when the pressing state of the operating body 6 is released, the intermediate gripping member 5, the cylindrical body 142, and the chuck 141 retreat by the elastic force of the coil spring 9 and the elastic force of the coil spring 44 and return to their original positions, reaching the states shown in FIGS. 9 and 10.
[0043] By releasing the locked state of the slider 3 and the front member 21 through the pressing operation of the operating body 6, in the state of Fig. 10, the front end of the slider 3 and the front end of the core 7 were approximately at the same position in the axial direction, but at the end of the operation, they protrude by a movement amount M (0.3 mm) in the forward direction. That is, in the present embodiment, by operating the operating portion 6 from the locked state of the slider 3 and the front member 21, the slider 3 is advanced. When the forward movement amount of the slider 3 when the guide portion 3a protrudes forward from the front end opening portion 21a of the front member 21 is defined as S1, and the forward movement amount of the core 7 is defined as S2, since S2 is longer by the movement amount M, the relational expression S1 < S2 is satisfied. Therefore, if the front end of the core 7 is approximately at the same position as the front end of the guide portion 3a of the slider 3 when the slider 3 retracts into the front member 21 (shaft cylinder 2), when the slider 3 is advanced and the guide portion 3a protrudes from the front member 21 (shaft cylinder 2), the core 7 protrudes by the movement amount M from the guide portion 3a, so that writing can be started immediately without further knocking operation.
[0044] In addition, in the present embodiment, in the state where the slider 3 is retracted and the protruding portion 3e (locking portion) of the slider 3 and the concave portion 21b (locked portion) of the front member 21 are locked, the rear contact portion 3c of the slider 3 and the slider pressing portion 142c of the cylindrical body 142 are configured to be in contact with each other. However, similar to the first embodiment, a gap L may be formed between the rear contact portion 3c and the slider pressing portion 142c (not shown). In this case, since the protruding amount of the core 7 from the front end of the slider 3 (guide portion 3a) when the slider 3 is advanced from the state where the protruding portion 3e (locking portion) and the concave portion 21b (locked portion) are locked can be the sum of the gap L and the movement amount M, it is suitable when it is desired to increase the protruding amount of the core 7 from the front end of the slider 3 when the slider 3 is advanced from the locked state.
Explanation of Reference Numerals
[0045] 1... mechanical pencil, 2... shaft cylinder, 21... front member, 21a... front end opening portion, 21b... concave portion (locked portion), 21c... stepped portion, 211... front member body, 212... inner piece, 212a... front portion, 22...Connection body, 23...Shaft cylinder body, 23a...front stage part, 23b...inner stage part, 231...Front axis, 232...rear axle, 3...slider, 3a...guide portion, 3b...step portion, 3c...rear contact portion, 3d...core holding portion, 3e...Protruding part (locking part), 31...Slider body, 32…O-ring, 33...Core holding member, 4...Lead advance mechanism, 41... chuck, 41a... head, 41b... chuck recess, 41c... rear stage 411...Chuck body, 412...rear cylinder body, 42...Cylindrical body, 42a...Central inner section, 42b...Tightening portion, 42c...Slider pressing portion, 42d...outer stage, 421...Cylindrical body, 422 front abutment member, 43…Steel ball, 44…coil spring, 5... Intermediate gripping member, 5a... Gripping part, 5b... Lead storage part, 5c... First contact part, 5d...second contact part, 51...Gripping member body, 52...rear cylinder, 6...Operation body, 7…Core, 8…coil spring, 9…coil spring, 11…Mechanical pencil, 14...Lead advance mechanism, 141... zipper, 141a... head, 141c... rear stage 1411...Chuck body, 142... cylindrical body, 142a... central inner section, 142c... slider pressing portion, 142d...outer stage, 1421...Cylindrical body, 145...fastener, 145a...clamp part L…gap, M...the amount of movement of the fastener.
Claims
1. The pen comprises a barrel having a barrel body and a tip member disposed in front of the barrel, a slider contained in the tip member and attached so as to be movable back and forth relative to the tip member, a chuck disposed within the barrel and gripping a writing lead, a cylindrical body disposed outside the chuck, and a tightening portion that tightens the chuck inside the cylindrical body, The slider has a guide portion at the front having an inner hole for guiding the lead, and a lead holding portion for holding the lead with a constant force, The guide portion protrudes forward from the front end opening of the tip member when writing, and is retractable into the barrel together with the lead when carried, in a mechanical pencil, an intermediate gripping member is disposed behind the cylindrical body and is slidable back and forth along the axial direction relative to the cylindrical body, the intermediate gripping member having a gripping portion that grips the cylindrical body, a first abutment portion that abuts against the chuck to limit its forward movement relative to the chuck, and a second abutment portion that abuts against the cylindrical body to limit its forward movement relative to the cylindrical body, a slider pressing portion at a front portion of the cylindrical body, the slider pressing portion being in contact with a rear portion of the slider; an operating body for operating the intermediate gripping member in a front-rear direction at the rear of the intermediate gripping member; a locking portion on an outer periphery of the slider that locks with a locked portion formed on an inner periphery of the tip member when the slider is retracted; An elastic member for biasing the slider forward is stretched between the slider and the tip member, where X is the minimum pressing force required to press the slider forward in the axial direction in order to release the locked state between the locking portion and the locked portion, and Y is the frictional force generated between the intermediate gripping member and the cylindrical body as a result of the intermediate gripping member gripping the cylindrical body, the relationship Y<X is satisfied, a control body is operated to advance the slider from a state in which the guide portion is retracted into the barrel and the locking portion and the locked portion are locked, and when the amount of advance of the slider when the guide portion protrudes forward from the front end opening of the tip member is S1 and the amount of advance of the lead is S2, the relationship S1 < S2 holds.
2. 2. The mechanical pencil according to claim 1, wherein when the guide portion is retracted into the barrel and the engaging portion and the engaged portion are engaged with each other, a gap is formed between the rear portion of the slider and the slider pressing portion.
3. The mechanical pencil according to claim 2, characterized in that the tightening portion is provided on an inner peripheral surface of the cylindrical body.
4. 3. The mechanical pencil according to claim 1, wherein a fastener capable of sliding back and forth relative to the cylindrical body is disposed inside the cylindrical body, and the fastening portion is provided on an inner peripheral surface of the fastener.
5. 5. The mechanical pencil according to claim 1, wherein the engaging portion of the slider has a protruding portion that protrudes outward, and the engaged portion of the tip member has a recessed portion that is recessed outward.
6. 6. The mechanical pencil according to claim 5, wherein the protrusion is an O-ring made of an elastic material.
Citation Information
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