JP2010105170A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which enables a lead to be prevented from uneven wearing with writing and keep efficiency of writing further enhanced. <P>SOLUTION: The mechanical pencil is constituted such that a knock member 12 is arranged in a sidewall of a grip part of a shaft tube 1 pushably in a radial direction of the shaft tube and a chuck 6 arranged in the shaft tube is moved forward and rearward interlocking with the pushing/releasing pushing of the knock member 12. The mechanical pencil is constituted such that the writing lead can be pushed out forward by the repetition of releasing and gripping of the writing lead L by the forward/rearward movements of the chuck 6. The mechanical pencil includes a rotary element 17 constituted so as to be able to move in a rotary direction and an axial direction in the shaft tube 1 as well as the chuck 5 gripping the writing lead L and the rotary element 17 constitutes a part of a rotating and driving mechanism gradually rotating the writing lead L receiving writing pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

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 (the drawn line becomes thinner) as writing proceeds.

  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.

Therefore, in order to solve the problems as described above, the chuck that grips the writing core is configured to be retracted 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.

  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 performs a slight backward and forward movement of the writing core accompanying writing (this is also referred to as a cushioning operation in the following). Have been filed in Japanese Patent Application Nos. 2007-339075 and 2007-339076 for rotating the writing core.

  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 configuration described above, it is possible to sequentially rotate the writing core by setting the retraction amount (cushion movement amount) of the core accompanying writing to a slight range of about 0.05 to 0.5 mm. Thereby, it is possible to provide a mechanical pencil excellent in practicality that does not cause a sense of incongruity in the writing operation.

  By the way, in the mechanical pencil having the above-mentioned configuration filed earlier by the applicant of the present application, the knock rod for feeding the writing core is arranged at the rear end portion of the shaft cylinder, so that the core is consumed due to the writing. Along with this, the operation of knocking the knock rod at the rear end portion of the shaft cylinder to feed the lead is forced. For this reason, each time the knocking operation is performed, the shaft cylinder is re-gripped, which is a factor of reducing the efficiency of writing, and there is still room for improvement.

  Therefore, the present invention increases the efficiency of writing by adding the above-described rotation mechanism of the writing core to the side knock type mechanical pencil that can perform the operation of drawing out the writing core without changing the shaft cylinder. It is intended to provide a mechanical pencil that can.

  On the other hand, 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. Therefore, when the rotation drive mechanism is to be mounted on a side knock type mechanical pencil, the arrangement of the knock member for performing side knock overlaps the rotation drive mechanism having a large diameter, and the grip portion is extremely thick. The problem arises that the design must be unbalanced in diameter.

  The present invention has been made to solve the above-described problems, and provides a mechanical pencil that can further improve the efficiency of writing by adding a rotational drive mechanism of a writing core to a side knock type mechanical pencil. It is something to try. In addition, even if the above-described side knock mechanism is adopted, it is an object to provide a mechanical pencil that enables the entire slimming including the grip portion by avoiding the overlap between the knock member and the rotation drive mechanism. To do.

  The mechanical pencil according to the present invention, which has been made to solve the above-described problems, has a knock member disposed on the side wall of the shaft cylinder so that it can be pressed in the radial direction or the longitudinal direction of the shaft cylinder, and the knock member is pressed and released. The chuck disposed in the shaft cylinder is moved back and forth in conjunction with the movement of the chuck so that the writing core can be fed forward by releasing and holding the writing core by the back and forth movement of the chuck. A mechanical pencil configured to be provided with a rotational drive mechanism that rotationally drives the rotor by a backward and forward movement of the rotor via the chuck by a writing pressure applied to the writing core, and the rotation of the rotor It is characterized in that it is configured to transmit motion to the writing core via the chuck.

  In this case, it is desirable that the rotation drive mechanism including the rotor is configured to move back and forth together with the chuck in conjunction with the pressing / releasing operation of the knock member. In addition, it is desirable that the rotor constituting the rotation drive mechanism is arranged in the shaft cylinder behind the knock member.

  On the other hand, a driving member that moves the chuck forward in conjunction with the pressing operation of the knock member is disposed in the shaft cylinder, and when the knock member is not pressed, the driving member contacts the chuck side. It is desirable that a gap be formed between the two portions and the non-contact portion of the driving member on the chuck side so as not to be joined in the axial direction.

  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 arranged to face the first and second cam surfaces, respectively, are provided, and a first retraction of the chuck by the retraction operation of the chuck by the writing pressure is performed. The cam surface is in contact with and meshed with the first fixed cam surface, and when the writing pressure is released, the second cam surface of the annular rotor contacts and meshes with the second fixed cam surface. In the state where the first cam surface on the rotor side is meshed with the first fixed cam surface, the second cam surface on the rotor side and the second fixed cam surface are , Against one tooth of the cam in the axial direction The rotor-side first cam surface and the first fixed cam surface are set in a phase-shifted relationship and the rotor-side second cam surface is engaged with the second fixed cam surface. Is set to a half-phase shifted relationship 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, by adopting a side knock type in which a knock member is arranged on the side wall of the shaft cylinder so that it can be pressed in the radial direction of the shaft cylinder, and the chuck can be moved back and forth in conjunction with the pressing and releasing of the knock member. The writing core can be fed out without changing the shaft cylinder. Accordingly, it is possible to provide a mechanical pencil that can further improve the efficiency of writing, in addition to the above-described effect of rotating the writing core.

  Further, a knock member is provided, for example, in the vicinity of the grip portion relatively in front of the shaft cylinder, and a rotor constituting a rotation drive mechanism is disposed in the shaft cylinder behind the position where the knock member is mounted. By doing so, the arrangement of the knock member and the rotor can be dispersed in the axial direction, and a mechanical pencil in which the overall configuration including the grip portion provided with the knock member is slimmed can be provided.

  Hereinafter, a mechanical pencil according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a perspective view showing the entire configuration broken by 90 degrees in the axial direction, and FIG. 2 is a sectional view showing the entire configuration. 3 to 5 are cross-sectional views showing the parts A to C in FIG. 2 in an enlarged manner, and FIGS. 6 to 8 show parts A to C in FIG. 2 when the side knocking operation is performed. It is sectional drawing expanded. In each figure, the same parts are indicated by the same reference numerals, but in FIG. 1 and FIG. 2, only the representative parts are provided with reference numerals.

  FIG. 3 mainly shows the tip portion, and the tip portion indicated by reference numeral 2 is attached to the distal end portion of the shaft tube 1 constituting the outline of the mechanical pencil. A cylindrical core case 3 is accommodated coaxially with the shaft cylinder 1 in the shaft cylinder 1, and a first relay pipe 4 is fitted to the outer end of the core case 3. Yes.

  The first relay pipe 4 has a structure in which the diameter thereof is reduced in three steps toward the front, and the tip portion of the core case 3 is fitted to the inner peripheral surface of the intermediate step portion of the relay pipe 4. It is attached in a state. And it attaches to the inner peripheral surface of the front-end | tip part of the relay pipe 4 in the state which the rear-end part of the chuck | zipper 5 was fitted.

  A through hole is formed in the chuck 5 along the axis, the tip is divided into a plurality of pieces, and the divided tip is loosely fitted in a fastener 6 formed in a ring shape. Yes. The ring-shaped fastener 6 is mounted on the inner surface of the tip member 7 arranged so as to cover the periphery of the chuck 5 so as to be slightly slidable in the axial direction.

  A short pipe member 8 is fitted on the inner surface of the rear end portion of the front end member 7, and the front end portion of the pipe member 8 comes into contact with the rear end portion of the slidable fastener 6 to tighten it. It acts to restrict the position of the tool 6. The tip member 7 is formed with a guide pipe for guiding the writing core L at its tip, and a rubber holding chuck having a through hole in the center on the inner peripheral surface of the tip member 7. 9 is housed.

  With the above-described configuration, a linear core insertion hole extending from the core case 3 to the tip member 7 through the through holes formed in the shaft cores of the core case 3, the relay pipe 4, the chuck 5, and the holding chuck 9, respectively. The writing core (replacement core) L described above is inserted into the linear core insertion hole. A coiled return spring 10 is disposed between the annular step formed on the inner periphery of the short pipe member 8 and the tip of the relay pipe 4. Therefore, the chuck 5 is biased in the direction of retreating in the tip member 7 by the action of the return spring 10.

  In the mechanical pencil shown in the figure, the relay pipe 4 is moved forward by a pressing operation (hereinafter also referred to as a knocking operation) of a knocking member, which will be described later, disposed on the side wall in the vicinity of the grip position of the barrel 1. Works. As a result, as shown in FIG. 6, the chuck 5 connected to the relay pipe 4 is pushed forward, and the fastener 6 disposed at the tip of the chuck 5 slides slightly forward in the tip member 7. Stop.

  As the chuck 5 further advances, the tip of the chuck 5 comes out of the fastener 6 and protrudes forward, so that the gripping state of the writing core L is released. At this time, the writing core L is held by friction in a through hole formed in the holding chuck 9. Then, when the knocking operation of the knocking member, which will be described later, is released, the chuck 5 is retracted as shown in FIG. 3 by the action of the return spring 10, and the tip end portion is accommodated in the fastener 6. Work to hold.

  That is, the writing core L is released and gripped by the back and forth movement of the chuck 4 by repeated knocking operation of a knocking member, which will be described later, and the writing core acts so as to be sequentially advanced forward from the chuck 4.

  FIG. 4 shows a knock member disposed on the side wall near the grip portion of the shaft tube 1 and a knock mechanism portion for advancing the chuck 4 by its operation. That is, a rectangular window hole 1a is formed in the side wall near the grip portion of the shaft tube 1, and the knock member 12 is attached to the window hole 1a.

  The knock member 12 is formed so that the central portion protrudes slightly in a mountain shape toward the outside in the mounted state in the window hole 1a, side walls are formed on both sides thereof, and the shaft core is formed. An orthogonal cross-sectional shape is formed in a U shape. A rectangular notch 12a is formed on both side walls on the rear end side of the knock member 12, and the notch 12a is engaged with the rear edge of the window hole 1a. That is, the knock member 12 is attached to the shaft cylinder 1 so that it can be pressed in the radial direction of the shaft cylinder 1 with the notch 12a as a fulcrum.

  On the other hand, a drive member 13 that moves forward by a knock operation of the knock member 12 is accommodated in the shaft cylinder 1. The drive member 13 has an axial core portion penetrating through the core case 3, and an inclined surface 13a is formed at the rear end thereof. The inclined surface 13a is configured such that the corners 12b at the front end of the side wall on both sides of the knock member 12 are in contact with each other.

  Therefore, when the knock member 12 is knocked as shown in FIG. 7, the corner 12b slides in contact with the inclined surface 13a, thereby pushing the drive member 13 forward.

  The front half of the drive member 13 has a slightly thinner outer diameter, and a spring member 14 is provided between the annular step formed thereby and the annular step formed in the mouth portion 2. Contained. The spring member 14 acts to urge the drive member 13 backward. Accordingly, as shown in FIGS. 4 and 7, the drive member 13 acts to move back and forth in conjunction with the pressing / releasing operation of the knock member 12.

  On the other hand, as shown in FIGS. 3 and 6, the front end portion 13 b of the driving member 13 abuts on the rear end portion 4 a of the first relay pipe 4 by the forward movement of the driving member 13, and the first relay pipe. 4, the chuck 5 is moved forward. Further, based on the backward movement of the drive member 13 by the spring member 14, the chuck 5 is moved back to the state shown in FIG.

  Thus, the chuck disposed in the shaft cylinder is moved back and forth in conjunction with the pressing / releasing operation of the knock member disposed on the side wall of the shaft cylinder with the above-described configuration. The writing core can be fed forward by repeatedly releasing and holding the writing core by movement.

  In the state shown in FIG. 3 in which the knock member 12 is not pressed, the front end portion 13b of the drive member 13 and the rear end portion 4a of the first relay pipe 4 are not joined in the axial direction. A gap is formed between the two. In other words, a gap is formed between the contact portion 13b of the drive member on the chuck side and the non-contact portion 4a of the drive member on the chuck side so as not to be joined in the axial direction.

  By forming a gap between the two as described above, when the rotational driving operation of the writing core L is performed based on the cushioning operation of the writing core L, which will be described later, the driving member 13 rotates the writing core L. It is possible to effectively prevent inhibition. In addition, by forming the above-described gap, it is possible to prevent the driving member 13 from being pushed back each time the writing core L is cushioned, thereby causing the knocking member 12 to be moved in small steps for each writing operation. Can be prevented. Furthermore, by forming the above-described gap, it is possible to prevent a problem that the rotational driving operation of the writing core L is inhibited to the extent that the hand touches the knock member 12 during writing.

  5 and 8 show a rotation driving mechanism of the writing core L including the rotor. A rotor 17 constituting the rotation driving mechanism is connected to the chuck 5 side via a second relay pipe 16 fitted to a rear end portion of the core case 3, and a rear end of the second relay pipe 16. Are connected to the inner surface of the front end portion of the rotor 17.

  As shown in FIGS. 5 and 8, the rotor 17 has a thick-diameter portion whose diameter is increased at the center in the axial direction, and a first cam surface is provided on one end surface (rear end surface) of the large-diameter portion. 17a is formed, and a second cam surface 17b is formed on the other end surface (front end surface) of the large diameter portion.

  On the other hand, on the rear end portion side of the rotor 17, a cylindrical upper cam forming member 18 rotatably supports the rotor 17 so as to cover the rear end portion of the rotor 17, A fixed cam surface (also referred to as a first fixed cam surface) 18 a is formed at the front end portion of the cam forming member 18 so as to face the first cam surface 17 a of the rotor 17.

  Further, a fixed cam surface (also referred to as a second fixed cam surface) 19 a formed on the lower cam forming member 19 is disposed so as to face the second cam surface 17 b of the rotor 17. The lower cam forming member 19 is formed in a cylindrical shape, is attached in a fitted state so as to cover a part of the outer peripheral surface of the upper cam forming member 18, and is formed on a part of the inner peripheral surface thereof. The fixed cam surface 19a is formed in the annular stepped portion.

  Regarding the relationship between the first and second cam surfaces 17a, 17b formed on the rotor 17, the first fixed cam surface 18a, and the second fixed cam surface 19a and their mutual actions, Details will be described later with reference to FIGS.

  A cylindrical stopper 21 is fitted to the inner surface of the rear end portion of the upper cam forming member 18 formed in a cylindrical shape, and is formed in a cylindrical shape and moves in the axial direction with the front end portion of the stopper 16. A coil-like spring member 23 is mounted between the possible torque canceller 22.

  The spring member 23 acts to urge the torque canceller 22 forward, and is configured to be pushed forward by the torque canceller 22 that has received this urging force.

  Therefore, the upper cam forming member 18 and the lower cam forming member 19 have a cylindrical outer shape, and the writing core rotation drive mechanism including the rotor 17 is provided between the inner peripheral surface of the shaft cylinder 1. A floating mechanism is formed which forms a gap and moves back and forth with the chuck 5 in conjunction with the pressing / releasing operation of the knock member 12. A coiled spring is formed between an annular step formed on a part of the outer peripheral surface of the lower cam forming member 19 and an annular step formed on a part of the inner peripheral surface of the shaft cylinder 1. A member 25 is interposed.

  The spring member 25 contracts in a flexible manner corresponding to the forward movement of the rotary drive mechanism that accompanies the forward movement of the chuck 5 by the knocking operation of the knock member 12, and from the chuck 5 when the knock member 12 is not operated. It acts to urge the whole of the rotational drive mechanism backward. In addition, the spring member 25 acts to prevent the upper cam forming member 18 and the lower cam forming member 19 from freely rotating about the axis.

  According to the configuration described above, the rotor 17 rotates around the shaft core together with the chuck 4 via the first relay pipe 4, the core case 3, and the second relay pipe 16 while the chuck 4 holds the writing core. It is accommodated in the shaft tube 1 so as to be possible. When the mechanical pencil is not used (in a case other than the writing state), the rotor 17 is urged forward via the torque canceller 22 by the action of the spring member 23.

  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 5 moves backward against the urging force of the spring member 23. Thus, the rotor 17 is also retracted in the axial direction. Therefore, the first cam surface 17a formed on the rotor 17 shown in FIG. 5 is brought into mesh with the first fixed cam surface 18a.

  FIGS. 9A to 9C and FIGS. 10D and 10E explain the basic operation of the rotation drive mechanism for rotating the rotor 17 by the above-described operation step by step. 9 and 10, reference numeral 17 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 17a is formed in an annular shape. Similarly, a second cam surface 17b that is continuously serrated along the circumferential direction is formed in an annular shape on the other end surface of the rotor 17 (the lower surface in the figure).

  On the other hand, as shown in FIGS. 9 and 10, the first fixed cam surface 18 a that is continuously serrated along the circumferential direction is also formed on the annular end surface of the upper cam forming member 18. A second fixed cam surface 19 a that is continuously serrated along the circumferential direction is also formed on the annular end surface of the lower cam forming member 19.

  The first cam surface 17 a, the second cam surface 17 b formed on the rotor, the first fixed cam surface 18 a formed on the upper cam forming member 18, and the second cam surface formed on the lower cam forming member 19. The cam surfaces formed in a sawtooth shape along the circumferential direction of the fixed cam surface 19a are formed so that their pitches are substantially the same. In FIG. 9 and FIG. 10, the circles drawn at the center of the rotor 17 indicate the rotational movement amount of the rotor 17.

  FIG. 9A shows the relationship among the upper cam forming member 18, the rotor 17, and the lower cam forming member 19 when the pencil is not used (in a case other than the writing state). In this state, the second cam surface 17b formed on the rotor 17 is biased toward the second fixed cam surface 19a side of the lower cam forming member 19 with the biasing force of the spring member 23 shown in FIGS. It is contacted by. At this time, the first cam surface 17a on the rotor 17 side and the first fixed cam surface 18a are set so as to be shifted by a half phase (half pitch) with respect to one tooth of the cam in the axial direction. ing.

  FIG. 9B 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 17 moves with the spring 5 as the chuck 5 moves backward. The member 23 is contracted and retracted in the axial direction. Thereby, the rotor 17 moves to the upper cam forming member 18 side.

  FIG. 9C shows a state where the writing pressure is applied to the writing core by using the mechanical pencil, and the rotor 17 is in contact with the upper cam forming member 18 and retracted. In this case, the rotor 17 The formed first cam surface 17a meshes with the first fixed cam surface 18a on the upper cam forming member 18 side. As a result, the rotor 17 receives a rotational drive corresponding to a half phase (half pitch) of one tooth of the first cam surface 17a. In the state shown in FIG. 9C, the second cam surface 17b on the rotor 17 side and the second fixed cam surface 19a 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. 10D 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 17 is moved by the action of the spring member 23 described above. Advance in the axial direction. Thereby, the rotor 17 moves to the lower cam forming member 19 side.

  Further, FIG. 10E shows a state in which the rotor 17 advances and contacts the lower cam forming member 19 side by the action of the spring member 23 described above. In this case, the rotor 17 is formed on the rotor 17. The second cam surface 17b meshes with the second fixed cam surface 19a on the lower cam forming member 19 side. As a result, the rotor 17 is again subjected to rotational driving corresponding to a half phase (half pitch) of one tooth of the second cam surface 17b.

  Therefore, as indicated by a circle drawn at the center of the rotor 17, the rotor 17 has the first and second cam surfaces 17 a, as the rotor 17 receives the writing pressure and reciprocates in the axial direction. The writing core L received by the rotation drive corresponding to one tooth (1 pitch) of 17b and held by the second relay pipe 16, the core case 3, the first relay pipe 4 and the chuck 5 is the same. Is driven to rotate.

  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 the reciprocation of the rotor 17 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.

  Furthermore, according to the mechanical pencil having the above-described configuration, the tip member 7 that guides the writing core L moves in the same direction as the chuck 5 moves backward and forward along with the writing operation. 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, when the writing core L receives a rotational motion, the distal end member 7 similarly receives a rotational motion, and the distal end member 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 22 that pushes the rotor 17 forward by receiving the biasing force of the coiled spring member 23 is between the front end surface of the torque canceller 22 and the rear end surface of the rotor 17. It acts to prevent the rotational movement of the rotor 17 generated by repeating the writing action from being transmitted to the spring member 23 by generating a slip.

  In other words, since the torque canceller 22 formed in a cylindrical shape is interposed between the rotor 17 and the spring member 23, the rotational movement of the rotor 17 is caused by the above-described sliding action. By acting so as to prevent transmission to the member 23 and causing the torsional return (spring torque) of the spring member 23 to occur, the problem of obstructing the rotational operation of the rotor 17 can be solved.

  In the embodiment, an annular concave groove is formed along the peripheral side surface of the torque canceller 22 shown in FIGS. 5 and 8, and a rubber O-ring 26 is fitted therein. The O-ring 26 is formed on the inner peripheral surface of the upper cam forming member 18 when the torque canceller 22 moves backward due to the writing pressure or when the torque canceller 22 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 23 shown in FIGS. 5 and 8, there remains a problem that the feeling of being “spotted” or “clicking” during writing is not good. Therefore, by arranging the O-ring 26 along the peripheral side surface of the torque canceller 22 and utilizing the damper function thereby, the above-described problems can be reduced.

  5 and 8, a cylindrical body portion 28 integrally formed with a clip 28 a is fitted into the axial cylinder 1 at the rear end portion of the axial cylinder 1, and further, the rear end portion of the cylindrical body portion 28 is An opening is formed in the axial direction, and a cap 29 is fitted into the opening, and the cap 29 can be removed when the writing core is replenished.

  According to the embodiment described above, the use of the rotational drive mechanism of the writing core in the side knock type mechanical pencil can prevent uneven wear of the writing core accompanying writing and can improve the writing efficiency more. A unique effect described in the column of the effect of the invention described above can be obtained, such as providing a pencil.

  In the above-described embodiment, the knock member is disposed on the side wall of the shaft cylinder so as to be able to press in the radial direction of the shaft cylinder. The knock member is disposed on the side wall of the shaft cylinder in the longitudinal direction of the shaft cylinder. The structure arrange | positioned so that pressing is possible is also employable, and the same effect can be acquired also in such a structure.

It is the perspective view which showed the whole structure of the mechanical pencil concerning this invention in the state fractured | ruptured partially. It is sectional drawing which showed the whole structure of the mechanical pencil similarly. It is an expanded sectional view in the A section 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. FIG. 3 is an enlarged cross-sectional view of a portion A in FIG. 2 when a side knock operation is performed. FIG. 3 is an enlarged cross-sectional view of a portion B in FIG. 2. FIG. 3 is an enlarged sectional view of a C portion in FIG. 2. FIG. 9 is a schematic diagram for explaining step by step the rotational driving action of a rotor mounted on the embodiment shown in FIGS. FIG. 10 is a schematic diagram for explaining the rotational driving action of the rotor following FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Mouth part 3 Core case 5 Chuck 6 Fastener 7 Tip member 9 Holding chuck 10 Return spring 12 Knock member 13 Drive member 17 Rotor 17a 1st cam surface 17b 2nd cam surface 18 Upper cam formation member 18a 1st Fixed cam surface 19 Lower cam forming member 19a Second fixed cam surface 21 Stopper 22 Torque canceller 23 Spring member 28 Cylindrical portion 28a Clip

Claims (7)

A knock member is arranged on the side wall of the shaft cylinder so as to be able to press in the radial direction or the longitudinal direction of the shaft cylinder, and the chuck disposed in the shaft cylinder is moved back and forth in conjunction with the pressing / releasing operation of the knock member. A mechanical pencil configured to be able to unwind the writing core forward by repeating the release and gripping of the writing core by the longitudinal movement of the chuck,
A rotation drive mechanism for rotating the rotor by a retreating and advancing operation of the rotor via the chuck by a writing pressure applied to the writing core; and the rotational movement of the rotor via the chuck A mechanical pencil that is configured to transmit to   2. The mechanical pencil according to claim 1, wherein the rotation driving mechanism including the rotor is configured to move back and forth together with the chuck in conjunction with a pressing / releasing operation of the knock member.   3. The mechanical pencil according to claim 1, wherein a rotor that constitutes the rotation drive mechanism is disposed in the shaft cylinder at a rear side of the position where the knock member is disposed.   A driving member that moves the chuck forward in conjunction with the pressing operation of the knock member is disposed in the shaft cylinder, and when the knock member is not pressed, a contact portion of the driving member toward the chuck side 4. The gap according to claim 1, wherein a gap is formed between the chuck member and the non-contact portion of the driving member so as not to be joined in the axial direction. 5. The listed mechanical pencil. 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 arranged to face the surfaces, respectively,
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. The 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 5. The mechanical pencil according to claim 1, 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 5.   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 6, wherein the mechanical pencil is configured to prevent transmission to the spring member.

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