JP5215281B2 - 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 tube, the sharp side of the writing core is written in contact with the paper surface sequentially, so that the stroke becomes thicker as the drawing progresses. Can be avoided. However, if an attempt written while rotating the barrel, inconvenience that the operation of pick up the barrel is needed is generated with the progress of the writing, so the efficiency of writing significantly overlooked score and.

  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. A mechanical pencil having a mechanism is disclosed in the following prior art documents.

Japanese Patent No. 3882272 Japanese Patent No. 3885315

  By the way, according to the mechanical pencil disclosed in the above-mentioned prior art document, the vertical protrusions and the vertical grooves are alternately arranged in the shaft cylinder, and the cam portion having the inclined surface is formed in an annular shape so as to straddle them. Has been. 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. This utilizes a known karn knock mechanism that is frequently used in knock type ballpoint pens and the like.

  According to the mechanical pencil having the above-described configuration, 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 necessary. 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 to get over the formed vertical projection is required. Since this operation needs to be performed relatively frequently each time the writing core is reduced, there remains a problem of reducing the writing efficiency.

  Therefore, in order to solve the problem of the mechanical pencil disclosed in the above-mentioned prior art document, the applicant of the present application slightly moves back and forwards the writing core accompanying writing (this is also referred to as cushioning operation hereinafter). Have been filed in Japanese Patent Application Nos. 2007-339074 and 2007-339075 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 rotate sequentially in one direction, and this rotational motion is transmitted to the writing core via a chuck that grips the writing core. Yes.

  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, it is desirable to arrange the rotation driving mechanism for rotating the writing core in the shaft cylinder as close as possible to the mouth portion from which the writing core protrudes. According to this configuration, it is possible to reduce the influence of each component constituting the rotation drive mechanism and the influence of the core misalignment such as the rotation relay member that relays the rotation drive mechanism and the writing core. The degree of play between the slider through which the writing core is inserted can be reduced.

  However, even with this type of mechanical pencil equipped with a rotary drive mechanism, it is necessary to diversify in response to customer needs. For example, a grip part made of a relatively thick coated rubber is placed on the front end side of the barrel. It is conceivable to employ a configuration in which a side knock member for extending a writing core is disposed on the side wall of the shaft cylinder. In this case, a configuration is required in which the rotation drive mechanism described above is arranged on the rear half side of the shaft cylinder, and the rotation drive mechanism and the chuck portion that holds the writing core are connected by a rotation relay pipe. .

  Therefore, the design of the entire mechanical pencil including the rotary drive mechanism changes depending on where the rotary drive mechanism is arranged in the shaft cylinder. Especially for the above-mentioned rotary drive mechanism part that requires a high level of design experience, a lot of time and cost are required for a new development design corresponding to the change of the arrangement position in the shaft cylinder. Will have the problem.

  The present invention has been made by paying attention to the above-mentioned problems in a mechanical pencil equipped with a rotational drive mechanism for a writing core. An object of the present invention is to provide a mechanical pencil capable of easily adopting the rotational drive mechanism having the same configuration for each of the mechanical pencils having the various configurations described above having different arrangement positions of the mechanisms. .

Mechanical pencil according to the present invention made in order to solve the above, transmitted to the chuck through the lead case for accommodating the writing lead the knocking operation of the knocking member, the back-and-forth movement of the chuck based on the knocking operation It is configured so that the writing core can be released and gripped, and the writing core can be fed forward, and the chuck can rotate around the axis and forward and backward while holding the writing core. As described above, the mechanical pencil housed in the shaft cylinder, the rotational drive mechanism capable of converting the reciprocating motion in the axial direction into the rotational motion is constituted by one unit independent of the mechanical pencil body, and the shaft The rotation drive mechanism and the chuck are accommodated in a cylinder and connected to the chuck via the relay member by being connected via the relay member. A longitudinal movement based on a writing pressure applied to the held writing core is transmitted as a reciprocating motion to the rotational drive mechanism, and a rotational motion generated by the rotational drive mechanism is transmitted to the chuck. And

In this case, it is desirable that the relay member is formed by a flexible material, further the relay member, that are arranged coaxially on the outside of the lead case connected to a rear end portion of the chuck Is desirable.

  In a preferred embodiment, the rotation drive mechanism constituted by one independent unit is pressed against a part of the shaft cylinder by the shaft spring, thereby preventing the rotation operation of the rotation drive mechanism in the shaft cylinder. Configured to be

  On the other hand, in a preferred embodiment of the rotational drive mechanism, a rotor to which the relay member is connected is provided, and the rotor is formed in an annular shape with first and second end surfaces in the axial direction thereof being first and second. Second cam surfaces are respectively formed, and first and second fixed cam surfaces are provided so as to face the first and second cam surfaces, respectively, and the chuck is retracted by the writing pressure. The first cam surface of the annular rotor is brought into contact with and meshed with the first fixed cam surface, and the second cam surface of the rotor becomes the second fixed by releasing the writing pressure. The first cam surface on the rotor side is engaged with the first fixed cam surface and the second cam surface on the rotor side and the second cam surface on the rotor side in a state where the first cam surface on the rotor side is engaged with the first fixed cam surface. Second fixed cam surface is axial In the state where the phase is shifted with respect to one tooth of the cam and the second cam surface on the rotor side is engaged with the second fixed cam surface, the first on the rotor side is set. The cam surface and the first fixed cam surface are set so as to be out of phase with respect to one tooth of the cam in the axial direction.

  In this case, the rotary drive mechanism has a cushion that urges the second cam surface of the rotor to abutment with the second fixed cam surface when the writing pressure is released. Desirably, a spring is provided.

  Further, in addition to the above-described configuration, a torque canceller that generates a slip between the rear end portion of the rotor and the rear end portion of the rotor is interposed between the rear end portion of the rotor and the cushion spring in the rotation drive mechanism. Preferably, the rotor is configured to prevent the rotational motion of the rotor from being transmitted to the cushion spring.

  According to the above-described mechanical pencil according to the present invention, a rotary drive mechanism is provided for rotating the rotor by receiving a writing pressure, and the rotational movement of the rotor is transmitted to the writing core via the chuck. Therefore, since the writing core is gradually rotated with the writing operation, it is possible to prevent the writing core from being unevenly worn as the writing progresses, and the thickness of the drawn line and the density of the drawn line greatly change. Can be eliminated.

  In addition, since the rotation drive mechanism is configured by a single unit independent of the mechanical pencil body, by determining the length dimension of the relay pipe as a relay member that connects the rotation drive mechanism and the chuck, The arrangement position of the rotation drive mechanism in the shaft tube can be arbitrarily determined. Therefore, according to the diversification of this type of mechanical pencil, it is possible to have the versatility of making the rotational drive mechanisms available to each, and compared to the case of individually developing and designing, It can contribute to reduction.

It is sectional drawing which showed the front half part of the mechanical pencil concerning this invention. It is sectional drawing which showed the latter half part similarly. It is the front view and center sectional view which show the drawing-out unit of a writing lead, and the rotational drive mechanism of a writing lead. It is sectional drawing which showed the structure of the front shaft and the grip member. It is an expanded sectional view of the rotation drive mechanism of a writing core. It is a schematic diagram explaining the rotation drive action of the rotor provided in the rotation drive mechanism step by step. FIG. 7 is a schematic diagram for explaining the rotational driving action of the rotor following FIG. 6. It is the external appearance perspective view and sectional drawing of the torque canceller with which the rotational drive mechanism was equipped. It is sectional drawing which showed the relationship between the torque canceller with which the rotational drive mechanism was equipped, and the cylinder member. It is sectional drawing of the state seen in the arrow direction from the aa line in FIG. 9, a bb line, and cc line. It is the perspective view of the rotor which changed the angle and showed the structural example of the display part which displays the rotation state of a rotor. It is an external view of the mechanical pencil concerning this invention which shows the rotation state of a rotor. It is sectional drawing which expanded and showed the front-end | tip part of the mechanical pencil shown in FIG.

  A mechanical pencil according to the present invention will be described based on an embodiment shown in the drawings. 1 and FIG. 2 are sectional views showing the entire configuration. FIG. 1 shows the first half of the mechanical pencil, and FIG. 2 shows the second half. In the drawings shown below, the same portions are denoted by the same reference numerals, but in the overall views shown in FIGS. 1 and 2, the representative portions are denoted by the reference numerals.

  A mouth end portion (cutipula) indicated by reference numeral 1 is detachably attached by being screwed onto a tip end portion of a tip shaft 2 constituting a shaft cylinder made of a metal material. And the cylindrical core case 3 is coaxially accommodated along the center part of the front axis | shaft 2 and the rear axis | shaft mentioned later. As shown in FIG. 3, a short shaft core case joint 4 is attached to the tip of the core case 3, and a brass chuck 5 is connected through the core case joint 4.

  In the chuck 5, a writing core hole (not shown) is formed along the axis of the chuck 5, the tip is divided into a plurality of pieces, and the divided tip is formed into a ring shape by brass. It is loosely fitted in the tool 6. The ring-shaped fastener 6 is mounted on the inner surface of a pipe joint 7 arranged so as to cover the periphery of the chuck 5.

  A cylindrical slider 8 is attached to the front end portion of the pipe joint 7 so that the front end portion of the pipe joint 7 is accommodated in the front end portion 1 and protrudes from the front end portion. The tip pipe 9 which guides is attached. A rubber holding chuck 10 having a through hole formed in the shaft core portion as shown in FIG. 3 is accommodated on the inner surface of the slider 8.

  With the configuration described above, a linear core insertion hole reaching the tip pipe 9 is formed through a through hole formed in the chuck 5 from the core case 3 and a through hole formed in the shaft core of the holding chuck 10. A writing core (not shown) is inserted into the linear core insertion hole. A coiled chuck spring 11 is disposed between the pipe joint 7 and the core case joint 4.

  The rear end portion of the chuck spring 11 is accommodated in the state of contact with the front end surface of the core case joint 4, and the front end portion of the chuck spring 11 is in contact with an annular member formed on the inner peripheral surface of the pipe joint 7. Has been. Therefore, the chuck 5 is urged by the action of the chuck spring 11 in the retreating direction, that is, in the direction of gripping the writing core.

In the writing lead feeding unit having the above-described configuration, the lead case 3 moves forward in the shaft cylinder by knocking a knock member (knock bar) described later. At this time, the outer flange of the pipe joint 7 comes into contact with the inner flange at the tip of the tip shaft 2 and the advancement of the pipe joint 7 is prevented, so that the tip of the chuck 5 protrudes relatively from the fastener 6 and the chuck 5 The holding state of the writing core by is released. When the knocking operation is released, the lead case 3 and the chuck 5 are retracted in the shaft cylinder by the action of the chuck spring 11.

  At this time, the writing core is held by friction in a through hole formed in the holding chuck 10, and in this state, the chuck 5 is retracted and its tip is accommodated in the fastener 6. The core is again held. That is, the chuck 5 is moved back and forth by repeated knocking operation of a knock bar, which will be described later, whereby the writing core is released and gripped, and the writing core acts so as to be sequentially advanced forward from the chuck 5.

  As shown in FIGS. 1 and 4, a grip member 13 is mounted on the front shaft 2 constituting the shaft cylinder so as to surround the front shaft 2. As shown in detail in FIG. 4, the grip member 13 is mounted between the metal shaft coupling 14 fitted to the rear end portion of the front shaft 2 and the above-described mouth portion 1. The grip member 13 is composed of an inner layer 13b formed of a rubber material and a coating layer 13a formed of the same rubber material, and a gel-like substance is filled between the two as necessary. Has been made.

  A synthetic resin shaft ornament 15 is fitted so as to cover the flange 14 a formed at the front end portion of the shaft coupling 14, and the rear end portion of the grip member 13 is covered with the shaft ornament 15. It is installed as shown.

  A spiral screw is formed on the outer peripheral surface of the shaft coupling 14, and a rear shaft 17 constituting a shaft cylinder is screwed and attached using this screw as shown in FIG. 2. An outer shaft 18 in which a clip portion 18a is integrally formed is attached so as to cover the outer side of the rear shaft 17. The outer shaft 18 is a retaining ring screwed to the rear end portion of the rear shaft 17. 19 is attached so as to be sandwiched between the shaft decoration 15 and the shaft decoration 15.

  In this embodiment, as described above, the relatively thick grip member 13 is mounted on the front shaft 2 side, so that the rotation driving mechanism 21 of the writing core has the grip member 13 as shown in FIG. It is arranged between the rear shaft 17 and the core case 3 which are behind the mounting position. Although the structure of the rotation drive mechanism 21 will be described in detail later, it is configured by a single unit independent of the mechanical pencil body and is accommodated in the shaft cylinder.

  The rotary drive mechanism 21 unitized so that it can be used as a general-purpose product has a pipe member (hereinafter also referred to as a relay pipe) that functions as a relay member made of a flexible material as shown in FIG. .) 22 is connected to the rear end, and the front end of the relay pipe 22 is connected to the pipe joint 7 that supports the chuck 5.

  That is, the relay pipe 22 is coaxially arranged so as to cover the core case 3, and the relay pipe 22 performs a retraction and forward movement (cushion movement) of the writing core based on the writing movement. And the rotational motion by the rotational drive mechanism 21 generated by the cushion operation is transmitted to the pipe joint 7 and the chuck 5 via the relay pipe 22.

  As shown in FIG. 2, the rotational drive mechanism 21 is urged rearward by a shaft spring 24 interposed between the shaft coupling 14 and the front end portion thereof. The rear end portion of the rotary drive mechanism 21 is in contact with the stepped portion 17 a formed by the reduced diameter in the rear shaft 17 by the urging force of the shaft spring 24.

  That is, in this embodiment, the rotation drive mechanism 21 that is unitized is restricted from rotating by friction due to contact with the stepped portion 17a in the rear shaft 17, and the rotation drive mechanism generated by the cushion operation described above. It acts to transmit the rotational motion by 21 to the chuck 5 side. The mounting of the rotation drive mechanism 21 in the shaft tube is not limited to the above-described configuration, and the rotation drive mechanism 21 may be mounted on a part of the shaft tube by, for example, fitting means.

  FIG. 5 is an enlarged view of the structure of the unitized rotation drive mechanism 21. The rotary drive mechanism 21 includes a rotor 26 formed in a cylindrical shape, and the relay pipe 22 is fitted to the inner peripheral surface of the rotor 26 at the front end portion of the rotary drive mechanism 21. Are combined.

  The rotor 26 has a large-diameter portion with a slightly larger diameter near the front end, and a first cam surface 26a is formed on one end surface (rear end surface) of the large-diameter portion. A second cam surface 26b is formed on the other end surface (front end surface). On the other hand, a cylindrical upper cam forming member 27 is disposed so as to be rotatable with respect to the rotor 26 so as to cover the rear end side of the rotor 26. A cylindrical lower cam forming member 28 is fitted and attached to the outer periphery of the front end.

  A fixed cam surface (also referred to as a first fixed cam surface) 27 a is formed on the front end surface of the upper cam forming member 27 facing the first cam surface 26 a of the rotor 26. A fixed cam surface (also referred to as a second fixed cam surface) 28a is formed on the inner surface of the front end portion of the lower cam forming member 28 facing the second cam surface 26b of the rotor 26.

  Regarding the relationship between the first and second cam surfaces 26a, 26b formed on the rotor 26, the first fixed cam surface 27a, and the second fixed cam surface 28a and their interaction, Details will be described later with reference to FIGS.

  As shown in FIG. 5, the cylinder member 30 is fitted on the rear end portion side of the upper cam forming member 27 described above, and the insertion hole 30 a into which the core case 3 can be inserted into the rear end portion of the cylinder member 30. Is formed. A torque canceller 31 that is formed in a cylindrical shape and is movable in the axial direction is disposed in the cylinder member 30. Between the front end of the inner peripheral surface of the torque canceller 31 and the rear end of the inner peripheral surface of the cylinder member 30. A coiled cushion spring 32 is attached to the.

  The cushion spring 32 acts to urge the torque canceller 31 forward, and is pushed by the torque canceller 31 receiving this urging force, so that the rotor 26 acts forward.

  As described above, the rotation drive mechanism 21 is formed in a space portion through which the core case 3 passes and is isolated from the core case 3, and is integrally coupled by the members 26 to 32 described above. Are unitized.

  According to the configuration of the rotation drive mechanism 21 described above, the rotor 26 can rotate around the shaft core together with the chuck 5 via the relay pipe 22 in a state where the chuck 5 holds the writing core. When the mechanical pencil is not in a writing state, the rotor 26 is biased forward via the torque canceller 31 by the action of the cushion spring 32.

  On the other hand, when a mechanical pencil is used, that is, when a writing pressure is applied to the writing core protruding from the tip pipe 9, the chuck 5 moves backward against the urging force of the cushion spring 32. Thus, the rotor 26 is also retracted in the axial direction. Therefore, the first cam surface 26a formed on the rotor 26 shown in FIG. 5 is brought into mesh with the first fixed cam surface 27a.

  6 (A) to 6 (C) and FIGS. 7 (D) and 7 (E) explain the basic operation of the rotation driving mechanism 21 that rotates the rotor 26 by the above-described operation in order. 6 and 7, reference numeral 26 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 26a is formed in an annular shape. Similarly, a second cam surface 26b that is continuously serrated along the circumferential direction is formed in an annular shape on the other end surface (the lower surface in the drawing) of the rotor 26.

  On the other hand, as shown in FIGS. 6 and 7, the first fixed cam surface 27a continuously formed in a sawtooth shape along the circumferential direction is also formed on the annular end surface of the upper cam forming member 27, A second fixed cam surface 28 a that is continuously serrated along the circumferential direction is also formed on the annular end surface of the lower cam forming member 28.

  Then, the first cam surface 26 a formed on the rotor 26, the second cam surface 26 b, the first fixed cam surface 27 a formed on the upper cam forming member 27, and the first cam surface formed on the lower cam forming member 28. The cam surfaces formed in a sawtooth shape along the circumferential direction of the two fixed cam surfaces 28a are formed so that their pitches are substantially the same. 6 and 7, the circles drawn at the center of the rotor 26 indicate the rotational movement state of the rotor 26.

  FIG. 6A shows the relationship among the upper cam forming member 27, the rotor 26, and the lower cam forming member 28 when the mechanical pencil is not used (in the case other than the writing state). In this state, the second cam surface 26b formed on the rotor 26 is brought into contact with the second fixed cam surface 28a side of the lower cam forming member 28 by the urging force of the cushion spring 32 shown in FIG. Has been. At this time, the first cam surface 26a on the rotor 26 side and the first fixed cam surface 27a are set so as to have a half-phase (half-pitch) offset from one cam tooth in the axial direction. ing.

  FIG. 6B shows an initial state in which the writing pressure is applied to the writing core by using the mechanical pencil. In this case, the rotor 26 retracts in the axial direction by contracting the cushion spring 32 via the chuck 5 and the relay pipe 22. Thereby, the rotor 26 moves to the upper cam forming member 27 side.

  FIG. 6C shows a state in which the writing pressure is applied to the writing core by using the mechanical pencil, and the rotor 26 is in contact with the upper cam forming member 27 side. In this case, the rotor 26 is formed on the rotor 26. Further, the first cam surface 26a meshes with the first fixed cam surface 27a on the upper cam forming member 27 side. Thereby, the rotor 26 receives a rotational drive corresponding to a half phase (half pitch) of one tooth of the first cam surface 26a. In the state shown in FIG. 6C, the second cam surface 26b on the rotor 26 side and the second fixed cam surface 28a 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. 7D shows an initial state in which the writing with the mechanical pencil is finished and the writing pressure on the writing core is released. In this case, the rotor 26 is moved by the action of the cushion spring 32 described above. Advance in the axial direction. Thereby, the rotor 26 moves to the lower cam forming member 28 side.

  Further, FIG. 7E shows a state in which the rotor 26 is in contact with the lower cam forming member 28 side by the action of the cushion spring 32 described above. In this case, the second formed on the rotor 26 is shown. The cam surface 26b meshes with the second fixed cam surface 28a on the lower cam forming member 28 side. As a result, the rotor 26 again receives a rotational drive corresponding to a half phase (half pitch) of one tooth of the second cam surface 26b.

  Therefore, as indicated by the circles drawn at the center of the rotor 26, the rotor 26 has the first and second cam surfaces 26a, The writing core held by this via the relay pipe 22, the pipe joint 7 and the chuck 5 is also rotationally driven in the same manner by receiving rotational driving corresponding to one tooth (1 pitch) of 26 b.

  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 26 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 pipe 9 and the slider 8 for guiding the writing core operate integrally with the rotor 26 via the pipe joint 7 and the relay pipe 22. As the chuck 5 moves backward and forward, the tip pipe 9 and the slider 8 move in the same direction via the relay pipe 22.

  Therefore, even if the writing core slightly moves back and forth (cushioning) with the writing operation, the tip pipe 9 that guides the writing core also moves in the same direction, so that the axial direction between the tip pipe 9 and the writing core is axial. Relative movement does not occur, and the lead-out dimension of the writing core from the tip pipe 9 can be kept constant.

  Since the tip pipe 9 and the slider 8 are coupled to the rotor 26 via the relay pipe 22, the tip pipe 9 and the slider 8 are similarly subjected to rotational movement when the writing core is subjected to rotational movement. As a result, the tip pipe 9 and the writing core rotate together.

  Therefore, according to the mechanical pencil having the above-described configuration, it is possible to solve the problem that a writing core protruding dimension from the tip pipe 9 changes each time during writing and gives an uncomfortable feeling. Furthermore, the change in the protruding dimension of the writing core from the tip pipe 9 can prevent the core from being broken by cutting the core with the tip pipe, and also eliminates the problem of contaminating the writing surface by scraping the core. be able to.

  The cylindrical torque canceller 31 that pushes the rotor 26 forward by receiving the biasing force of the coiled cushion spring 32 is between the front end face of the torque canceller 31 and the rear end face of the rotor 26. By causing slipping, it acts to prevent the rotational movement of the rotor 26 caused by repeated writing action from being transmitted to the cushion spring 32.

  In other words, the torque canceller 31 is interposed between the rotor 26 and the cushion spring 32, thereby preventing the rotational motion of the rotor 26 from being transmitted to the spring 32 due to the sliding action described above. Thus, the problem that the rotating operation of the rotor 26 is obstructed can be solved by generating the twisting return (spring torque) of the spring 32.

  By the way, according to the rotation drive mechanism 21 described above, in the above-described cushioning operation against the urging force of the cushion spring 32 shown in FIG. The problem remains. In order to solve this problem, an adhesive medium, preferably adhesive grease (not shown) is interposed between the peripheral side surface of the torque canceller 31 and the inner peripheral surface of the cylinder member 30, so that the cylinder member 30. It is desirable that the torque canceller 31 that moves in the axial direction has a damper effect.

  For this purpose, as shown in FIG. 5, adhesive grease injection holes 30 b are formed at positions opposite to the side wall of the cylinder member 30 by 180 degrees. And when the adhesive grease is injected into the torque canceller 31 side through the injection hole 30b, the convex member 31a which seals the grease and spreads the grease over the entire peripheral side surface of the torque canceller 31 and A groove 31b is formed.

  More detailed configurations and operations of the cylinder member 30 and the torque canceller 31 will be described with reference to FIGS. 8A shows an external configuration of the torque canceller 31, and FIGS. 8B and 8C are cross-sectional views of the torque canceller 31 cut at positions orthogonal to each other in the circumferential direction. is there.

  Convex members 31a are formed at approximately the center positions of the torque canceller 31 that face each other at 180 degrees. Further, immediately after the axial direction adjacent to the convex member 31a of the torque canceller 31, a groove portion 31b that is continuous along the circumferential direction is formed. Further, a circumferential side surface orthogonal to the convex member 31a of the torque canceller 31 is formed with a face-grooving portion 31c processed into a flat shape in the axial direction.

  FIG. 9 illustrates an order in which the torque canceller 31 having the above-described configuration is inserted into the cylinder member 30 and the adhesive grease is injected using the injection hole 30b of the cylinder member 30. That is, on the inner peripheral surface of the cylinder member 30, a concave portion 30c that accommodates the pair of convex members 31a in the torque canceller 31 is formed so as to communicate with the injection hole 30b along the axial direction. Has been.

  FIG. 9A shows the positional relationship between the two when the adhesive grease is injected using the injection hole 30 b of the cylinder member 30. Note that FIG. 10A shows a cross-sectional view taken along the line aa in FIG. That is, in this state, the convex member 31 a in the torque canceller 31 is positioned in front of the injection hole 30 b formed in the cylinder member 30. In this state, the tip of the nozzle (not shown) is inserted into the injection hole 30b, and the adhesive grease is injected. Thereby, the grease is stored in the concave portion 30 c of the cylinder member 30.

  FIG. 9B shows a state where the torque canceller 31 is slightly pushed into the cylinder member 30 after the adhesive grease is injected, and is a cross-sectional view as viewed in the direction of the arrow from the line bb in FIG. 9B. Is shown in FIG. In this state, since the convex member 31a in the torque canceller 31 moves rearward from the injection hole 30b of the cylinder member 30, the injection hole 30b formed in the cylinder member 30 and the concave portion 30c in the cylinder member 30 are provided. Is blocked by the convex member 31a of the torque canceller 31, and the concave portion 30c is hermetically sealed. Thereby, the inside of the concave part 30c is made into a grease reservoir of adhesive grease.

  Next, FIG. 9C shows a state where the torque canceller 31 is further pushed into the cylinder member 30, and a cross-sectional view taken in the direction of the arrow from the line cc in FIG. 9C is shown in FIG. C). In this state, the adhesive grease in the concave portion 30c enclosed in the grease reservoir receives the pressing pressure by the torque canceller 31, and the volume is reduced. Therefore, the adhesive grease enters the groove portion 31b formed in the torque canceller 31. .

  The adhesive grease enters the circumferential side surface of the torque canceller 31 via the groove 31b, that is, a slight gap between the torque canceller 31 and the cylinder member 30, and spreads uniformly between the two.

  At this time, excess adhesive grease sealed in the grease reservoir formed by the concave portion 30c was formed on the peripheral side surface of the torque canceller 31 via the groove portion 31b as shown in FIG. 10C. It enters and is stored in the gap between the chamfered portion 31c and the cylinder member 30 (indicated by the same reference numeral 31c as that of the chamfered portion).

  In addition, as said adhesive grease, it is desirable to use the consistency of the range of 100-400, and as said adhesive grease, for example, the brand name "Shin-Etsu silicone grease" manufactured by Shin-Etsu Chemical Co., Ltd. product number: G330 -334, G340-342, G351-353, G631-633, etc. can be used suitably.

  Accordingly, a large viscous resistance is imparted to the sudden movement of the torque canceller 31 in the axial direction, and a damper function is provided that makes the viscous resistance extremely small for a static load that moves relatively slowly. Can do.

  Therefore, according to the above-described configuration, when the torque canceller moves forward by releasing the writing pressure, the damper function can be effectively provided, and the poor feeling of writing caused by the cushion operation described above can be effectively performed. Can be corrected. In addition, according to the above-described configuration, it is possible to easily inject and apply the adhesive grease that performs the damper function, and it is also possible to make the amount of adhesive grease applied to the portion that performs the damper function uniform. Therefore, it is possible to extremely reduce the variation in the damper characteristics.

  In the above-described embodiment, the cylinder member 30 is formed with a pair of injection holes 30b and a concave portion 30c, while the torque canceller 31 is formed with a pair of convex members 31a. This is a pair for the convenience of the adhesive grease injection and coating operation, and each of these can be formed to perform its function.

Returning to FIG. 2, a knock bar 35 as a knock member is slidably attached to the rear shaft 17 in the rear end portion of the rear shaft 17, and between the rear shaft 17 and the knock bar 35. A return spring 36 of a knock bar is disposed in the space portion. An abutting portion 35 a having a writing core replenishing hole is formed slightly closer to the rear end than the center of the knock bar 35. An eraser 37 is detachably attached to the rear end portion of the knock bar 35, and a knock cover 38 covering the eraser 37 is detachably attached to the peripheral surface of the rear end portion of the knock bar 35.

  The contact portion 35a of the knock bar 35 described above and the rear end portion of the core case 3 are configured to face each other at a predetermined interval. That is, the core case 3 is separated from the knock bar 35 at the interval without being mechanically connected to the knock bar 35.

  In this configuration, when the knocking rod 35 is knocked, the contact portion 35a of the knocking rod 35 hits the rear end of the lead case 3 and acts to push the lead case 3 forward. Thereby, as described above, the chuck 5 moves forward and acts so that the writing core is fed out from the tip pipe 9. When the knock operation is released, the knock bar 35 is retracted by the action of the return spring 36 and returns to the state shown in FIG.

  According to the configuration described above, the abutting portion 35a formed on the knock bar 35 and the rear end portion of the core case 3 are opposed to each other with a predetermined interval. Even if the shaft slightly retracts, the rear end portion of the lead case 3 does not collide with the contact portion 35a of the knock bar 35, and it is possible to prevent the rotation operation by the rotation drive mechanism 21 from being obstructed. .

  FIG. 11 and FIG. 12 show an example in which it is possible to display a state in which the rotor 26 in the rotary drive mechanism 21 is rotating in accordance with the writing operation. That is, FIGS. 11A and 11B are perspective views showing the configuration of the rotor 26 described above at different angles.

  The rotor 26 is preferably formed of a white resin material. The large-diameter portion of the rotor 26 on which the first cam surface 26a and the second cam surface 26b are formed has a periphery thereof. For example, a black display portion 26c is formed at a position opposite to the side surface. That is, white and black display portions 26c are formed at intervals of 90 degrees along the circumferential direction of the large diameter portion.

  On the other hand, FIGS. 12A and 12B show the appearance of a mechanical pencil so that the black and white display portion 26c applied to the rotor 26 can be seen through from the outside. The configuration is shown. In this example, the display unit 26c in black and white is displayed through the window 20 formed in a round shape, and (A) shows the display unit 26c as the rotor 26 rotates. A state where the boundary between white and black is displayed on the window 20 is shown. Moreover, (B) has shown a mode that the black part in the display part 26c was displayed on the window part 20 with the further rotation of the rotor 26. FIG.

  The configuration described above includes the lower cam forming member 28 of the rotation drive mechanism 21 shown in FIG. 5 that covers the outside of the rotor 26, the rear shaft 17 shown in FIG. 2 located outside the rotation drive mechanism 21, and the rear shaft 17. Each of the outer shafts 18 covering the outer side of each of the outer shafts 18 is formed of a light-transmitting resin, and for example, the peripheral side surface of the rear shaft 17 is subjected to a coating process while leaving the round-shaped window portion 20 described above. Can do.

  In this way, by configuring the rotation state of the rotor 26 to be visible from the outside, it is possible to easily determine whether the rotation drive mechanism is good or not by visual inspection in the operation check inspection at the time of manufacturing and assembling the mechanical pencil. . In addition, the user can have an interest or a kind of fun during use, and can contribute to a great differentiation of products.

  In the embodiment described above, the rotation drive mechanism 21 of the unitized writing core is located behind the mounting position of the grip member because the grip member having a relatively thick thickness is mounted on the shaft cylinder. The rotary drive mechanism 21 is accommodated in the rear shaft 17 and is connected to the chuck 5 via a relay pipe 22. When the relay pipe 22 having a relatively long dimension is employed as in this example, the relay pipe 22 is preferably made of a flexible material, such as polypropylene, together with the core case 3.

  By adopting the relay pipe 22 made of the flexible material described above, the molding error of each component constituting the rotation drive mechanism 21, a slight eccentricity based on the assembly, and the relay pipe 22 and the chuck 5 are included. Even if there is an eccentricity or the like caused by the mutual connection of the rotational drive parts of the writing core, the flexibility characteristic of the relay pipe 22 is utilized to effectively eliminate the trouble of the rotational movement of the writing core. be able to.

  Accordingly, as shown in FIG. 13 in which the peripheral portion of the lip portion 1 is enlarged, the degree of play between the inner peripheral surface of the lip portion 1 and the slider 8 can be further reduced. The problem of poor writing feel due to large play can be solved.

  In addition, as the above-mentioned mouth end portion 1, a so-called cuticle made by plating a synthetic resin material is used. Such a cutlery 1 is formed such that the plating thickness is thicker toward the outer side than the inner side (inner peripheral surface). Therefore, the inner peripheral surface of the cutlery 1 is formed in advance into a tapered surface 1a whose inner diameter slightly increases as it goes to the tip, thereby absorbing the difference in plating thickness, and the inner peripheral surface of the cutlery 1 and the slider 8 The degree of play during can be reduced.

1 Mouth (Cutipura)
2 Lead shaft (shaft tube)
3 Core Case 5 Chuck 6 Fastener 8 Slider 13 Grip Member 14 Shaft Joint 17 Rear Shaft (Shaft Tube)
18 Outer shaft 21 Rotation drive mechanism 22 Relay member (relay pipe)
24 shaft spring 26 rotor 26a first cam surface 26b second cam surface 27 upper cam forming member 27a first fixed cam surface 28 lower cam forming member 28a second fixed cam surface 30 cylinder member 31 torque canceller 32 cushion spring 35 knock bar (Knock member)
36 Return spring 37 Eraser 38 Knock cover

Claims (7)

Transmitted to the chuck through the lead case for accommodating the writing lead the knocking operation of the knock member performs gripping and release of the writing lead by back-and-forth movement of the chuck based on the knocking operation, it is possible to feed the writing lead forward A mechanical pencil housed in the shaft cylinder so that the chuck can rotate around the shaft core and move back and forth while holding the writing core,
A rotational drive mechanism capable of converting axial reciprocation into rotational motion is constituted by a single unit independent of the mechanical pencil main body and is accommodated in the shaft cylinder, and the rotational drive mechanism and the chuck are relayed. By being connected via a member, the longitudinal drive based on the writing pressure applied to the writing core gripped by the chuck via the relay member is transmitted as a reciprocating motion to the rotational drive mechanism, and the rotational drive A mechanical pencil configured to transmit the rotational motion generated by the mechanism to the chuck.   The mechanical pencil according to claim 1, wherein the relay member is made of a flexible material. Mechanical pencil according to claim 1 or claim 2, characterized in that the relay member is coaxially disposed outside of the lead case connected to a rear end portion of the chuck.   2. The rotary drive mechanism according to claim 1, wherein the rotary drive mechanism is configured to be prevented from rotating in the shaft cylinder by being pressed against a part of the shaft cylinder by a shaft spring. The listed mechanical pencil. The rotation drive mechanism includes a rotor to which the relay member is connected. The rotor is formed in an annular shape, and first and second cam surfaces are respectively provided on one end surface and the other end surface in the axial direction. And formed with first and second fixed cam surfaces so as to face the first and second cam surfaces, respectively.
Due to the retreating operation of the chuck by the writing pressure, the first cam surface of the annular rotor is brought into contact with and meshed with the first fixed cam surface, and the second of the rotor is released by the release of the writing pressure. The cam surface is configured to come into contact with 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. In a state in which the phase is shifted with respect to the teeth, and the second cam surface on the rotor side is engaged with the second fixed cam surface, the first cam surface on the rotor side and the first cam surface are 5. The mechanical pencil according to claim 1, wherein the fixed cam surface of 1 is set to have a phase shifted relationship with respect to one tooth of the cam in the axial direction. .   The rotation drive mechanism includes a cushion spring that urges the second cam surface of the rotor to abut with the second fixed cam surface in a meshed state when the writing pressure is released. The mechanical pencil according to claim 5, wherein the mechanical pencil is used.   A torque canceller that generates a slip between the rear end of the rotor and the rear end of the rotor in the rotational drive mechanism is interposed between the rear end of the rotor and the rotational movement of the rotor. The mechanical pencil according to claim 6, wherein the mechanical pencil is configured to prevent transmission to the cushion spring.

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