JP5525633B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil capable of rotating a writing core (replacement core) using writing pressure.

  When writing with a mechanical pencil, in general, the shaft tube is often used in a state slightly inclined with respect to the writing surface without being used in a state orthogonal to the writing surface (paper surface). In the case of writing with the shaft cylinder tilted in this way, the writing core becomes unevenly worn (decreased) as the writing progresses, so that a phenomenon occurs in which the drawn line becomes thicker than at the beginning of writing. Further, not only the thickness of the drawn line changes, but also the contact area of the writing core with respect to the writing surface changes, so that a phenomenon occurs in which the density of the drawn line changes as the writing progresses (the drawn line becomes thinner).

  In order to avoid the above-mentioned problem, if writing is performed while rotating the shaft cylinder, the sharp side of the writing core is written in contact with the paper surface sequentially, so that the drawn line becomes thicker according to the writing. Can be avoided. However, if it is attempted to write while rotating the shaft cylinder, the troublesome operation of holding the shaft cylinder as the writing progresses is required, and the writing efficiency is significantly reduced.

  In this case, when the outer casing of the shaft cylinder is formed in a cylindrical shape, it is not impossible to write while holding the shaft cylinder and rotating sequentially, but the outer casing is not cylindrical but has a protrusion on the middle. In the case of the attached design or the side knock type mechanical pencil, it is difficult to rewrite and write the shaft cylinder so as to sequentially rotate as described above.

  Therefore, in order to solve the problems as described above, the chuck that grips the writing core is configured to retract by receiving the writing pressure, and the writing core is rotated together with the chuck by using the retracting operation. Patent Documents 1 and 2 disclose mechanical pencils having a mechanism.

Japanese Patent No. 3882272 Japanese Patent No. 3885315

  By the way, according to the mechanical pencils disclosed in Patent Documents 1 and 2 described above, the vertical protrusions and the vertical grooves are alternately arranged in the shaft tube, and the cam portion having the inclined surface so as to straddle them is annular. Is formed. Further, a rotor having protrusions intermittently formed in the circumferential direction is accommodated in the shaft cylinder. Then, the rotor is pushed up by largely retreating the writing core, and the protrusion of the rotor rides on the vertical protrusion formed on the cam portion in the shaft cylinder, and falls into the adjacent vertical groove through the inclined surface. The rotator is rotated by use, and the rotational movement of the rotator is transmitted to the lead case to rotate the writing lead.

  According to the mechanical pencil described above, when the rotor is rotated, a large retraction stroke of the writing core necessary for the rotor-side protrusion to get over the vertical protrusion formed in the shaft cylinder is required. For this reason, when the lead is partially reduced by writing, the rotor-side protrusion is moved into the shaft cylinder by applying a pressure higher than the normal writing pressure to the writing core and moving the rotor back in the shaft cylinder. An operation different from the writing that causes the formed vertical protrusion to be overcome is required. Since this operation needs to be performed relatively frequently every time the lead is removed, there remains a problem of reducing the efficiency of writing.

  Therefore, in order to solve the problems of the mechanical pencils disclosed in Patent Documents 1 and 2 described above, the applicant of the present application slightly moves back and forwards the writing core accompanying writing (this is also referred to as cushioning operation in the following). And Japanese Patent Application No. 2007-339074, Japanese Patent Application No. 2007-339075, and the like.

  In the mechanical pencil according to the application, first and second cam surfaces are formed on each end surface of the rotor formed in a cylindrical shape, and the first cam surface is caused by a retreating operation of the rotor by writing pressure. Are brought into contact with and meshed with the first fixed cam surface. The second cam surface is brought into contact with and meshed with the second fixed cam surface by the forward movement of the rotor by releasing the writing pressure.

  The reciprocal meshing of the cams causes the rotor to sequentially rotate in one direction, and this rotational motion is transmitted to the writing core via a chuck that grips the writing core. .

  According to the above-described configuration, it is possible to sequentially rotate the writing core by setting the retreating amount (cushion movement amount) of the core accompanying writing to about 0.05 to 0.5 mm. It is possible to provide a mechanical pencil excellent in practicality that does not reduce the efficiency.

  By the way, in the mechanical pencil having the above-mentioned configuration filed earlier by the applicant of the present application, the rotational drive mechanism that rotationally drives the writing core by the cushion operation described above is disposed at a relatively forward position of the shaft cylinder, that is, near the grip portion of the pencil. ing. For this reason, when trying to arrange a thick grip member made of, for example, a rubber material in this portion, the thickness of the grip member increases in addition to the large-diameter rotation drive mechanism, and the grip portion is extremely thick. The problem arises that the design must be unbalanced in diameter.

  Further, in the mechanical pencil having the above-mentioned configuration filed earlier by the applicant of the present application, it is difficult to observe how the writing core is rotationally driven by writing because the rotation driving mechanism of the writing core is hidden in the grip portion described above. There is also a problem that it is difficult to grasp the rotational movement of the writing core accompanying writing.

  The present invention was made to solve the above-mentioned problems in the mechanical pencil provided with the previously-written writing core rotation drive mechanism, and even when a relatively thick grip member is disposed. An object of the present invention is to provide a mechanical pencil that enables slimming of the grip portion, and to provide a mechanical pencil that can easily grasp the rotational operation of the rotational drive mechanism during writing. Is.

  The mechanical pencil according to the present invention, which has been made to solve the above-described problems, extends the writing core forward by releasing and gripping the writing core by the back and forth movement of the chuck disposed in the shaft cylinder. The chuck is held in the shaft cylinder so as to be rotatable around the shaft core in a state where the chuck is gripped, and the chuck by the writing pressure of the writing core is held. A mechanical pencil that is configured to transmit a rotational movement of the rotor to the writing core via the chuck. In addition, a grip member is provided in front of the shaft cylinder so as to surround the shaft cylinder, and the rotation is inserted into the shaft cylinder behind the grip member mounting position. A rotor constituting a driving mechanism is disposed, and a relay pipe is provided in the shaft cylinder in a portion where the grip member is provided, and the chuck is retracted by the writing pressure of the writing core via the relay pipe. It is characterized in that the operation is transmitted to the rotor and the rotational motion of the rotor is transmitted to the chuck via the relay pipe.

  In this case, it is desirable that an inner diameter of the shaft cylinder in a portion where the grip member is provided is formed to be narrower than an inner diameter of the shaft cylinder in a portion where the rotor is disposed.

  On the other hand, a part of the relay pipe housed in the rotor or the shaft cylinder that is rotationally driven in conjunction with the rotation of the rotor can be visually recognized at a position behind the grip member mounting position. It is desirable to be configured.

  And the preferable form of the said rotational drive mechanism is that the rotor which comprises this is formed in an annular | circular shape, and the 1st and 2nd cam surface is each formed in the one end surface and other end surface of the axial direction, First and second fixed cam surfaces disposed on the shaft cylinder side so as to face the first and second cam surfaces are provided, and the annular movement is caused by the retreating operation of the chuck by the writing pressure. The first cam surface of the rotor is brought into contact with and meshed with the first fixed cam surface, and the second cam surface of the annular rotor becomes the second fixed cam surface by releasing the writing pressure. And the second cam surface on the rotor side and the second cam surface in a state where the first cam surface on the rotor side meshes with the first fixed cam surface. The fixed cam surface of the cam The second cam surface on the rotor side is engaged with the second fixed cam surface and the first cam surface on the rotor side and the first One fixed cam surface is set so as to have a half-phase shift with respect to one tooth of the cam in the axial direction.

  In this case, there is provided a spring member that urges the second cam surface of the annular rotor to come into contact with the second fixed cam surface in a state in which the writing pressure is released. It is desirable that

  Further, in addition to the above-described configuration, a torque canceller is interposed between the rear end portion of the rotor and the spring member, and is formed in a cylindrical shape to generate slip between the rear end portion of the rotor. Preferably, the rotor is configured to prevent the rotational motion of the rotor from being transmitted to the spring member.

  According to the above-described mechanical pencil according to the present invention, there is provided a rotation drive mechanism in which the rotor is reciprocated in the axial direction by receiving a writing pressure, and the rotational movement of the rotor is performed via the chuck. Transmitted to the core. Therefore, it is possible to prevent the writing core from being unevenly worn as the writing progresses, and it is possible to solve the problem that the thickness of the drawn line and the darkness of the drawn line change greatly.

  In addition, a grip member is provided in front of the shaft cylinder constituting the outline of the mechanical pencil so as to surround the shaft cylinder, and the rotation driving mechanism is provided in the shaft cylinder at a rear side of the mounting position of the grip member. Is configured in such a manner that the rotor that constitutes is arranged. Therefore, even when a relatively thick grip member is arranged, the grip member and the rotor are arranged at different positions in the axial direction of the shaft cylinder, so that the grip portion can be slimmed. A pencil can be provided.

  Furthermore, a part of the components housed in the rotor or the shaft cylinder that is rotationally driven in conjunction with the rotational operation of the rotor can be visually recognized at a position behind the mounting position of the grip member. By comprising, the mechanical pencil which can grasp | ascertain the rotation state of a writing core also during writing can be provided.

It is sectional drawing which showed the whole structure of the mechanical pencil concerning this invention. It is an expanded sectional view in the A part in FIG. It is an expanded sectional view in the B section in FIG. It is an expanded sectional view in the C section in FIG. It is an expanded sectional view in the D section in Drawing 1. It is an expanded sectional view in the E section in FIG. FIG. 7 is a schematic diagram for explaining step by step the rotational driving action of a rotor mounted on the embodiment shown in FIGS. FIG. 8 is a schematic diagram for explaining the rotational driving action of the rotor following FIG. 7.

  Hereinafter, a mechanical pencil according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a cross-sectional view showing the overall configuration, and FIGS. 2 to 6 are cross-sectional views showing enlarged portions A to E in FIG. In addition, although the same part is shown with the same code | symbol in each figure, the code | symbol is attached | subjected only to the representative part in FIG.

  FIG. 2 mainly shows the tip portion, and the tip portion indicated by reference numeral 2 is attached to the tip portion of the shaft tube 1 constituting the outline of the mechanical pencil. A cylindrical core case 3 is accommodated coaxially in the shaft cylinder 1 at the center of the shaft cylinder 1, and a chuck 4 is connected to the tip of the core case 3. In the chuck 4, a through hole is formed along the axis, the tip is divided into a plurality of pieces, and the divided tip is loosely fitted in a fastener 5 formed in a ring shape. Yes. The ring-shaped fastener 5 is attached to the inner surface of the tip member 7 disposed so as to cover the periphery of the chuck 4.

  The distal end member 7 has a guide pipe that guides the writing core L at its distal end, and its proximal end is fitted to the front end of the relay pipe 8 that is coaxially disposed around the core case 3. Has been. A rubber holding chuck 9 having a through hole formed in the shaft core portion is accommodated on the inner peripheral surface of the tip member 7.

  With the configuration described above, a linear core insertion hole reaching the tip member 7 is formed through a through hole formed in the chuck 4 from the core case 3 and a through hole formed in the shaft core of the holding chuck 9. The above-described writing core (replacement core) L is inserted into the linear core insertion hole. A coiled return spring 10 is disposed in a space formed between the relay pipe 8 and the chuck 4. One end (rear end) of the return spring 10 is formed on the end surface of the core case 3, and the other end (front end) of the return spring 10 is formed in the vicinity of the front end of the relay pipe 8. It is accommodated in a state in contact with the part. Therefore, the chuck 4 is urged in the backward direction by the action of the return spring 10.

  In the mechanical pencil shown in the drawing, the core case 3 moves forward in the shaft cylinder 1 by knocking a knock bar, which will be described later, disposed at the rear end portion of the shaft cylinder 1, and the tip of the chuck 4 is tightened. The gripping state of the writing core L is released by protruding from the tool 5. Then, the release of the knocking operation causes the lead case 3 and the chuck 4 to retreat in the shaft cylinder 1 by the action of the return spring 10.

  At this time, the writing core L is held in a through hole formed in the holding chuck 9. In this state, the chuck 4 retreats and the tip end portion is accommodated in the fastener 5 so that the writing core L is again held. That is, the chuck 4 is moved back and forth by repeating the knocking operation of a knock bar, which will be described later, whereby the writing core L is released and gripped, and the writing core acts so as to be sequentially fed forward from the chuck 4.

  As shown in FIGS. 2 to 3, a grip member 11 is attached to the front end portion of the shaft tube 1 so as to surround the shaft tube 1. The grip member 11 is formed, for example, from a rubber material to be somewhat thick, and is attached to the small diameter portion 1a of the shaft cylinder whose outer diameter is preliminarily formed at the front end portion of the shaft cylinder 1. Thereby, the outer diameter of the grip member 11 and the outer diameter of the rear end portion of the shaft tube 1 are substantially equal, or the outer diameter of the grip member 11 is configured to be slightly larger. As shown in FIG. 3, the rear end portion of the relay pipe 8 is formed to have a slightly thicker diameter and is fitted to the inner surface of the front end portion of the rotor 6 described later.

  As shown in FIG. 4, the rotor 6 is formed in a large diameter portion whose diameter is increased at the center in the axial direction, and a first cam surface 6 a is formed on one end surface (rear end surface) of the large diameter portion. The second cam surface 6b is formed on the other end surface (front end surface) of the large diameter portion. On the other hand, on the rear end side of the rotor 6, a cylindrical upper cam forming member 13 is attached in the shaft cylinder 1 so as to cover the rear end portion of the rotor 6, and the upper cam forming member A fixed cam surface (also referred to as a first fixed cam surface) 13 a is formed at the front end portion of 13 so as to face the first cam surface 6 a of the rotor 6.

  Further, a cylindrical lower cam forming member 14 is attached in the shaft cylinder 1 so as to face the second cam surface 6b of the rotor 6, and a fixed cam surface (first 2 is also formed.) 14a is formed. The relationship between the first and second cam surfaces 6a, 6b formed on the rotor 6, the first fixed cam surface 13a, and the second fixed cam surface 14a and their mutual actions are as follows. This will be described in detail later with reference to FIGS.

  3 and 4, the inner diameter of the shaft cylinder 1 in the portion where the grip member 11 is provided is smaller than the inner diameter of the shaft cylinder 1 in the portion where the rotor 6 is disposed. Is formed. As a result, the rotational drive mechanism including the rotor 6, the upper cam forming member 13, and the lower cam forming member 14 is accommodated in the shaft tube 1, and the grip member 11 formed to be somewhat thick as described above is placed in front of it. Even if it mounts | wears, the pencil which enabled slimming of a grip part can be provided.

  As shown in FIG. 5, a cylindrical stopper 16 is fitted on the inner surface of the rear end of the upper cam forming member 13 formed in a cylindrical shape, and is formed in a cylindrical shape with the front end portion of the stopper 16. A coil-shaped spring member 18 is attached between the torque canceller 17 that is movable in the axial direction.

  The spring member 18 acts to urge the torque canceller 17 forward, and the rotor 6 is configured to be pushed forward by being pushed by the torque canceller 17 receiving the urging force.

  According to the configuration described above, the rotor 6 is accommodated in the shaft cylinder 1 so as to be rotatable around the shaft core together with the chuck 4 via the relay pipe 8 in a state where the chuck 4 holds the writing core. Has been. When the mechanical pencil is not used (in a case other than the writing state), the rotor 6 is urged forward through the torque canceller 17 by the action of the spring member 18.

  On the other hand, when a pencil is used, that is, when a writing pressure is applied to the writing core L protruding from the tip member 7, the chuck 4 moves backward against the biasing force of the spring member 18. Thus, the rotor 6 is also retracted in the axial direction. Therefore, the first cam surface 6a formed on the rotor 6 shown in FIG. 4 is joined and engaged with the first fixed cam surface 13a.

  FIGS. 7A to 7C and FIGS. 8D and 8E explain the basic operation of the rotation driving mechanism for rotating the rotor 6 by the above-described operation in order. 7 and 8, reference numeral 6 schematically shows the above-described rotor, and one end surface (the upper surface in the drawing) is continuously serrated along the circumferential direction. The first cam surface 6a is formed in an annular shape. Similarly, a second cam surface 6b that is continuously serrated along the circumferential direction is formed in an annular shape on the other end surface of the rotor 6 (the lower surface in the figure).

  On the other hand, as shown in FIG. 7 and FIG. 8, the first fixed cam surface 13a continuously formed in a sawtooth shape along the circumferential direction is also formed on the annular end surface of the upper cam forming member 13, A second fixed cam surface 14 a that is continuously serrated along the circumferential direction is also formed on the annular end surface of the lower cam forming member 14.

  The first cam surface 6 a, the second cam surface 6 b formed on the rotor, the first fixed cam surface 13 a formed on the upper cam forming member 13, and the second cam formed on the lower cam forming member 14. The cam surfaces formed in a sawtooth shape along the circumferential direction of the fixed cam surface 14a are formed so that their pitches are substantially the same. In FIG. 7 and FIG. 8, the circles drawn at the center of the rotor 6 indicate the rotational movement amount of the rotor 6.

  FIG. 7A shows the relationship among the upper cam forming member 13, the rotor 6, and the lower cam forming member 14 in a state where the pencil is not used (in a case other than the writing state). In this state, the second cam surface 6 b formed on the rotor 6 is shown in FIGS. 4 and 5 on the second fixed cam surface 14 a side of the lower cam forming member 14 attached to the shaft cylinder 1. The spring member 18 is in contact with the biasing force. At this time, the first cam surface 6a on the rotor 6 side and the first fixed cam surface 13a are set so as to have a half-phase (half-pitch) offset with respect to one tooth of the cam in the axial direction. ing.

  FIG. 7B shows an initial state in which a writing pressure is applied to the writing core L by using a pencil. In this case, as described above, the rotor 6 moves with the spring 4 as the chuck 4 moves backward. The member 18 is contracted and retracted in the axial direction. Thereby, the rotor 6 moves to the upper cam forming member 13 attached to the shaft cylinder 1.

  FIG. 7C shows a state in which the writing pressure is applied to the writing core by using the mechanical pencil, and the rotor 6 is in contact with the upper cam forming member 13 and retracted. In this case, the rotor 6 The formed first cam surface 6a meshes with the first fixed cam surface 13a on the upper cam forming member 13 side. Thereby, the rotor 6 receives a rotational drive corresponding to a half phase (half pitch) of one tooth of the first cam surface 6a. In the state shown in FIG. 7C, the second cam surface 6b on the rotor 6 side and the second fixed cam surface 14a are half phase (half pitch) with respect to one tooth of the cam in the axial direction. It is set to be in a shifted relationship.

  Next, FIG. 8D shows an initial state in which the writing with the pencil is finished and the writing pressure with respect to the writing core L is released. In this case, the rotor 6 is moved by the action of the spring member 18 described above. Advance in the axial direction. Thereby, the rotor 6 moves to the lower cam forming member 14 side attached to the shaft cylinder 1.

  Further, FIG. 8E shows a state in which the rotor 6 has advanced by contacting the lower cam forming member 14 by the action of the spring member 18 described above. In this case, the rotor 6 is formed on the rotor 6. The second cam surface 6b meshes with the second fixed cam surface 14a on the lower cam forming member 14 side. As a result, the rotor 6 is again subjected to rotational driving corresponding to a half phase (half pitch) of one tooth of the second cam surface 6b.

  Therefore, as indicated by a circle drawn at the center of the rotor 6, the rotor 6 receives the first and second cam surfaces 6 a, The writing core L gripped by the rotational drive corresponding to one tooth (1 pitch) of 6b is held in the same manner via the relay pipe 8 and the chuck 4.

  According to the mechanical pencil having the above-described configuration, the rotor receives a rotational motion corresponding to one tooth of the cam each time by reciprocation of the rotor 6 in the axial direction by writing, and the writing core is sequentially rotated by this repetition. The Therefore, it is possible to prevent the writing core from being unevenly worn as the writing progresses, and it is possible to solve the problem that the thickness of the drawn line and the darkness of the drawn line change greatly.

  Further, according to the mechanical pencil having the above-described configuration, the tip member 7 for guiding the writing core L is fitted to the tip portion of the rotor 6 via the relay pipe 8, so that the chuck described above accompanying the writing operation is provided. With the backward and forward movement of 4, the tip member 7 moves in the same direction via the relay pipe 8. Therefore, even if the writing core L slightly moves back and forth (cushioning) with the writing operation, the tip member 7 that guides the writing core also moves in the same direction, so that the axial direction between the tip member and the writing core is axial. Relative movement does not occur, and the protruding dimension of the writing core from the tip member can be kept constant.

  Further, since the tip member 7 is coupled to the rotor 6 via the relay pipe 8, when the writing core L is subjected to a rotational motion, the tip member is similarly subjected to the rotational motion. 7 and the writing core L rotate together.

  Therefore, according to the mechanical pencil having the above-described configuration, it is possible to solve the problem that the writing core protruding dimension from the tip member changes each time during writing, and the user feels uncomfortable. Furthermore, it is possible to prevent the occurrence of core breakage due to cutting of the core at the tip member due to the change in the writing core protruding dimension from the tip member, and also to eliminate the problem of contaminating the writing surface by scraping the core. Can do.

  The cylindrical torque canceller 17 that pushes the rotor 6 forward by receiving the biasing force of the coiled spring member 18 is between the front end face of the torque canceller 17 and the rear end face of the rotor 6. By causing a slip, the rotational movement of the rotor 6 caused by the repeated writing action is prevented from being transmitted to the spring member 18.

  In other words, the torque canceller 17 formed in a cylindrical shape is interposed between the rotor 6 and the spring member 18, so that the rotational motion of the rotor is caused by the above-described sliding action. Therefore, the problem that the rotating operation of the rotor 6 is obstructed can be solved by causing the spring member 18 to twist back (spring torque).

  In the embodiment, as shown in FIGS. 4 and 5, a ring-shaped member 19 a is attached to the peripheral side surface of the torque canceller 17. An annular groove is formed along the outer peripheral surface of the ring-shaped member 19a, and a rubber O-ring 19 is fitted therein. The O-ring 19 is formed on the inner peripheral surface of the upper cam forming member 13 when the torque canceller 17 moves backward due to the writing pressure or when the torque canceller 17 moves forward by releasing the writing pressure. It acts to slide and fulfill the function as a damper.

  That is, in the above-described cushioning operation that opposes the urging force of the spring member 18 shown in FIG. 5, there remains a problem that the feeling of “coating” or “chatting” during writing is not good. Therefore, as shown in FIGS. 4 and 5, the O-ring 19 is disposed along the peripheral side surface of the torque canceller 17, and the above-described problem can be reduced by utilizing the damper function.

  Further, as another means for improving the unpleasant feeling in the cushion operation described above, an adhesive medium, preferably an adhesive grease, is provided between the peripheral side surface 17a of the torque canceller 17 shown in FIG. 5 and the stopper 16 facing it. It is conceivable to interpose (not shown). In this case, as the adhesive grease, it is desirable to use a grease having a consistency of 100 to 400. As the adhesive grease, for example, trade name “Shin-Etsu Silicone Grease” manufactured by Shin-Etsu Chemical Co., Ltd. G330 to 334, G340 to 342, G351 to 353, and G631 to 633 can be preferably used.

  As a result, a large viscous resistance is given to the sudden movement of the writing core L in the axial direction, and a damper function that gives a very small viscous resistance to a static load that moves relatively slowly can be given. it can.

  5 and 6 show the latter half of the pencil, and a cylindrical body portion 21 integrally formed with a clip 21 a is fitted into the axial cylinder 1 at the rear end portion of the axial cylinder 1. A cylindrical transmission member 22 is accommodated in the cylindrical portion 21, and a knock bar 23 is detachably attached to the rear end portion of the transmission member 22. A coiled spring member 24 is mounted between the front end portion of the transmission member 22 and the rear end portion of the stopper 16 described above, and the transmission member 22 is urged rearward by the spring member 24. It is configured as follows. The transmission member 22 is formed with an annular step portion 22a, and the step portion 22a abuts against the inner surface of the rear end portion of the cylindrical body portion 21, thereby preventing the transmission member 22 from coming out rearward. It is configured as follows.

  On the other hand, the front end portion of the knock bar 23 attached to the cylindrical transmission member 22 and the rear end portion of the core case 3 are opposed to each other with a predetermined interval. That is, in this embodiment, the lead case 3 is separated from the knock bar 23 without being mechanically connected to the knock bar 23.

  In the above configuration, when the knock bar 23 is knocked, the front end portion of the knock bar 23 hits the rear end portion of the lead case 3 and acts to push the lead case 3 forward as it is. Thereby, as described above, the chuck 4 moves forward and acts to feed out the writing core L from the tip member 7. Then, the knock bar 23 is retracted by the action of the spring member 24 by releasing the knock operation.

  According to the configuration described above, the tip end portion of the knock bar 23 and the rear end portion of the lead case 3 are opposed to each other with a predetermined distance. 3 does not collide with the knock bar 23. Then, by providing the predetermined distance between the two, the rotation operation of the lead case 3 by the rotation drive mechanism is not transmitted to the knock bar 23 side.

  In other words, even if the knock bar 23 is rotated unintentionally by a fingertip or the like, the rotation operation is not transmitted to the rotation drive mechanism via the lead case 3, and the rotation drive mechanism is obstructed. The problem can be solved.

  Furthermore, by giving the above-mentioned predetermined interval, even when the knock bar 23 is in contact with something, the problem of stopping the function of the rotational drive mechanism that rotationally drives the writing core L is solved. can do.

  In addition, it is desirable that the whole shaft tube 1 in the above-described embodiment or a part of the shaft tube 1 between the grip member 11 and the rotor 6 is formed of a transparent material. Thus, the shaft cylinder 1 is entirely or partially formed of a transparent material, so that the rotor 6 or the rotor is driven to rotate in a position behind the grip member 11 mounting position. A part of the components housed in the shaft cylinder, that is, a part of the relay pipe 8 connected to the rotor 6 in this embodiment can be visually recognized. Thereby, the above-described rotation state of the rotor 6 accompanying writing can be easily grasped.

  Further, as described above, a window hole is formed in a part of the shaft tube 1 at a position rearward of the mounting position of the grip member 11 without forming the whole or a part of the shaft tube 1 with a transparent material. Accordingly, the rotor 6 or a part of the relay pipe 8 connected to the rotor 6 can be visually recognized in the same manner, and the rotation state of the rotor 6 accompanying writing can be easily grasped.

  As described above, even if the whole or a part of the shaft cylinder 1 is formed of a transparent material or a window hole is provided in a part of the shaft cylinder 1, the above-described rotor 6 visually recognized from the outside. Alternatively, if, for example, a display body of a different color is formed on a part of the components that are rotationally driven in conjunction with the rotational operation of the rotor, the rotational state of the rotor 6 can be grasped more easily. .

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Mouth part 3 Core case 4 Chuck 5 Fastener 6 Rotor 6a 1st cam surface 6b 2nd cam surface 7 Tip member 8 Relay pipe 9 Holding chuck 10 Return spring 11 Grip member 13 Upper cam formation member 13a 1st Fixed cam surface 14 Lower cam forming member 14a Second fixed cam surface 16 Stopper 17 Torque canceller 18 Spring member 21 Cylindrical portion 21a Clip 22 Transmission member 23 Knock bar 24 Spring member

Claims (6)

The writing core is released and gripped by the back and forth movement of the chuck disposed in the shaft cylinder, so that the writing core can be fed forward, and the chuck is gripping the writing core. Rotation that is held in the shaft cylinder so as to be rotatable about the shaft core, and that rotates the rotor by retreating and moving forward of the rotor through the chuck by the writing pressure of the writing core. A mechanical pencil comprising a drive mechanism and configured to transmit the rotational movement of the rotor to the writing core via the chuck;
A grip member is provided in front of the shaft tube so as to surround the shaft tube, and a rotor constituting the rotation drive mechanism is disposed in the shaft tube behind the grip member mounting position. In addition, a relay pipe is provided in the shaft cylinder in the portion where the grip member is provided, and the retreat operation of the chuck due to the writing pressure of the writing core is transmitted to the rotor via the relay pipe, and A mechanical pencil configured to transmit the rotational motion of a rotor to the chuck via the relay pipe.   2. The sharp according to claim 1, wherein an inner diameter of the shaft cylinder in a portion where the grip member is provided is formed to be narrower than an inner diameter of the shaft cylinder in a portion where the rotor is disposed. Pencil.   A part of the relay pipe accommodated in the rotor or the shaft cylinder that is rotationally driven in conjunction with the rotation of the rotor is configured to be visible at a position behind the grip member mounting position. The mechanical pencil according to claim 1 or 2, wherein the mechanical pencil is provided. The rotor constituting the rotation drive mechanism is formed in an annular shape, and first and second cam surfaces are formed on one end surface and the other end surface in the axial direction, respectively, and the first and second cams are formed. First and second fixed cam surfaces disposed on the shaft tube side so as to face each other,
Due to the retraction operation of the chuck by the writing pressure, the first cam surface in the annular rotor is brought into contact with and meshed with the first fixed cam surface, and the release in the writing pressure releases the chuck in the annular rotor. A second cam surface is configured to abut against and mesh with the second fixed cam surface;
In a state where the first cam surface on the rotor side is engaged with the first fixed cam surface, the second cam surface on the rotor side and the second fixed cam surface are in the axial direction. The second cam surface on the rotor side is engaged with the second fixed cam surface and the first cam surface on the rotor side and the first The mechanical pencil according to any one of claims 1 to 3, wherein the fixed cam surface of 1 is set to have a half-phase shifted relationship with respect to one tooth of the cam in the axial direction. .   A spring member that urges the second cam surface of the annular rotor to engage with the second fixed cam surface in a state where the writing pressure is released; The mechanical pencil according to claim 4.   Between the rear end portion of the rotor and the spring member, a torque canceller that is formed in a cylindrical shape and generates slip between the rear end portion of the rotor is interposed, and the rotational movement of the rotor is performed. The mechanical pencil according to claim 5, wherein the mechanical pencil is configured to prevent transmission to the spring member.

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