JP2010036391A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which can rotate a core 9 thereof by a certain amount by adding writing pressure. <P>SOLUTION: The mechanical pencil includes an opening groove 13A on the inner axis 13, the front part of one sidewall of the opening groove 13A being significantly slanted and the rear part thereof being formed to be approximately vertical. Further, the other sidewall of the opening groove 13A is formed to be slated in approximately the same manner. Furthermore, a connection member 5 includes a protrusion 5D to be engaged in the opening groove 13A, and an engaging claw 5E is formed on the rear end of the connection member 5. A plurality of cam teeth 7B are formed circumferentially on the front end of the rotation member 7 provided in a rotatable manner against the inner axis 13. A chuck 1 is provided in a slidable but unrotatable manner in the longitudinal direction against the rotation member 7. In addition, a return spring 11 is provided in a suspended manner between the connection member 5 and the rotation member 7, and the cam teeth 7B of the rotation member 7 and the engagement claw 5E of the connection member 5 are usually spaced apart appropriately from each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mechanical pencil that rotates a core by a certain amount by applying writing pressure.

  In general, the writing instrument is written with a slight tilt, but when writing with the mechanical pencil tilted, the lead is reduced by one side, so that the end face of the lead becomes elliptical and the writing width gradually increases. It was. Therefore, it was necessary to rotate the mechanical pencil in order to maintain a narrow writing width.

In order to solve this problem, a chuck body rotating means is provided in which the chuck body rotates by the retreating operation of the core held by the chuck body, and the chuck body rotating means rotates in contact with the slider and the slider. A mechanical pencil composed of a child and a cam portion provided on the inner wall surface of the shaft cylinder is known. (See Patent Document 1)
Japanese Patent No. 3882272

  However, the structure in which the chuck body rotating means is configured by a conventionally known slider, a rotor that contacts the slider, and a cam portion provided on the inner wall surface of the shaft cylinder is structurally a shaft cylinder. The interval between the vertical groove portions provided on the inner wall surface of the slab was not made fine, and the core was greatly rotated by one pressing operation, which was very difficult to write.

  An object of this invention is to provide the mechanical pencil which eliminates the said subject.

  The present invention includes a main body, a chuck built in the main body, a fastener fitted to the head of the chuck, and a chuck spring that urges the chuck rearward in the longitudinal direction. A mechanical pencil that is pressed by a fastener and holds the lead when the chuck is closed, attaches a tip member to a connector that receives the fastener, and advances the lead by advancing the chuck, and has an opening groove on the inner shaft. One side wall of the opening groove is largely inclined at the front portion and the rear portion is formed substantially vertically, and the other side wall is formed to be inclined substantially the same. A projection that engages with the groove is formed, a locking claw is formed at the rear end of the connector, and a large number of cam teeth are provided in the circumferential direction at the front end of the rotating member that is rotatable with respect to the inner shaft. Forming and against the rotating member The rack is configured to be slidable in the longitudinal direction and non-rotatable, a return spring is stretched between the coupling member and the rotating member, and the rotating member is elongated by a spring having a larger mounting load than the return spring. The first gist is that the forward claw is biased forward, the rotating member is pressed against the inner shaft, and the latching claw of the normal connector and the cam teeth of the rotating member are appropriately separated.

  The second gist is that a spring is stretched between the rotating member and the pressing member.

  Furthermore, a third aspect is to loosely fit a weight body between a connector connected to the rear part of the chuck and the pressing member, advance the chuck by the inertial force of the weight body, and feed the core.

  In the mechanical pencil of the present invention, when writing pressure is applied to the lead, the lead is sequentially rotated and does not decrease, and writing can always be performed with a narrow writing width. Furthermore, since the amount of rotation of the core for each time can be set to be small, the edge portion of the core is evenly worn, and there is no possibility that the core edge is lost and the core is caught on the paper surface.

  By applying the writing pressure, the lead was rotated sequentially and the lead was not reduced, and a mechanical pencil that could always write with a narrow writing width was realized.

  Hereinafter, the mechanical pencil according to the first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, and 6. Moreover, let the left side of FIG. 1 be the front, and let the right side be back. Further, the left rotation direction is set to the left rotation toward the front, and the right rotation direction is set to the right rotation toward the front. First, a front part of a metal chuck 1 made of brass or the like is divided into three parts, and a synthetic resin connector 2 is press-fitted and fixed to the rear part of the chuck 1. Further, a core tank 3 made of a synthetic resin pipe material is press-fitted and fixed to the rear part of the connector 2. A key groove 2A extending from the rear is formed in the connector 2 at a relative position.

  A fastener 4 is externally fitted to the head 1A of the chuck 1, and a chuck spring 6 is stretched between the inner stage 5A of the connector 5 that receives the fastener 4 and the front end of the connector 2 with a load of about 150 g. The chuck 1 is urged backward in the longitudinal direction.

  Further, the connecting member 5 is formed with an elastic piece 5C having kerfs 5B formed on both sides, and a protrusion 5D is formed on the elastic piece 5C. Moreover, the latching claw 5E which protruded back from the rear end of the connector 5 is formed. The locking claw 5E is formed with a sharp tip. The core tank 3 is provided with a rotating member 7 covered from behind, a key 7A formed inside the rotating member 7 is engaged with the key groove 2A of the connector 2, and the rotating member 7 is connected to the connector 2. In the longitudinal direction, it is slidable and non-rotatable. A large number of cam teeth 7B are formed in the circumferential direction at the front end of the rotating member 7, and the cam teeth 7B are formed in a sawtooth shape and have an inclined surface.

  Further, a lead guide member 8 is detachably fitted to the connector 5, and a lead holder 10 for holding the lead 9 with an appropriate force is built in the lead guide member 8.

  Further, a return spring 11 is provided between the connector 5 and the rotating member 7, and the weight body 12 is loosely fitted to the core tank 3.

  Further, an opening groove 13A is formed in the inner shaft 13, and the left side wall 13B of the opening groove 13A has a large front portion and is inclined in the right rotation direction, and a rear portion is formed substantially vertically. Further, the right side wall 13C of the opening groove 13A is formed to be inclined in the clockwise direction substantially the same.

  The protrusion 5D of the connector 5 is inserted into the opening groove 13A of the inner shaft 13 while the elastic piece 5C is bent, and the protrusion 5D is engaged with the opening groove 13A. The rotating member 7 is rotatably inserted into the inner shaft 13. Further, a washer 14 is provided at the rear part of the rotating member 7. A plurality of protrusions 14A are provided at the front end of the washer 14 at equal intervals in the circumferential direction. The protrusions 14A are formed in a substantially hemispherical shape and protrude forward.

  The mechanism portion including the inner shaft 13, the core guide member 8, the coupling tool 5, the rotating member 7, the chuck 1, the connector 2, the core tank 3, and the chuck spring 6 is inserted from the rear of the shaft cylinder 15. Further, the tip member 16 is detachably screwed to the connector 5 protruding from the front end of the shaft tube 15. Further, a pressing member 17 is inserted into the shaft cylinder 15, and a spring 18 is provided between the washer 14 and the pressing member 17. An eraser 19 is attached to the rear inner side of the pressing member 17, and a knob 20 that covers the eraser 19 is externally fitted to the rear outer side. Further, a head crown 21 is attached to the rear portion of the shaft tube 15 to prevent the mechanism portion and the pressing member 17 from coming off. The tip member 16, the shaft cylinder 15 and the head crown 21 constitute a main body. In this state, the spring 18 stretched between the washer 14 and the pressing member 17 is set to a load of about 300 g at the time of attachment, and abuts the rotating member 7 against the inner shaft 13. Further, the pressing member 17 is in contact with the head crown 21. Further, the return spring 11 stretched between the connector 5 and the rotating member 7 is set to a load of about 70 g, and the locking claw 5E of the connector 5 and the cam teeth 7B of the rotating member 7 are separated from each other. Composed. Further, the projection 5D of the connector 5 is brought into contact with the front end of the opening groove 13A of the inner shaft 13.

  In the mechanical pencil of the first embodiment described above, the chuck 1 is advanced by the inertial force of the weight body 12 generated by shaking the shaft cylinder 15, and the core 9 is fed out by a certain amount. When the knob 20 is pressed, the chuck 1 moves forward and the spare core 9 in the core tank 3 follows the chuck 1.

  Next, when writing is performed in a state where the lead 9 protrudes from the lead guide member 8 by a certain amount, the lead 9 is pressed against the paper surface 22. Then, first, the return spring 11 is compressed, and the chuck 1 moves backward together with the core 9 by a certain amount. At this time, the projection 5D of the connector 5 moves backward while rotating counterclockwise along the inclined right side wall 13C.

  Then, when the locking claw 5E of the connector 5 comes into contact with the cam teeth 7B of the rotating member 7, the rotating member 7 also rotates counterclockwise together with the connector 5. Since the rotating member 7 is in contact with the substantially hemispherical protrusion 14A of the washer 14, the frictional resistance is reduced and the rotating member 7 rotates smoothly. At this time, since the key 7A of the rotating member 7 is engaged with the key groove 2A of the connector 2, the chuck 1 and the core 9 together with the rotating member 7 rotate counterclockwise by a certain amount. Further, when the lead 9 is retracted and the protrusion 5D is brought into contact with the rear end of the opening groove 13A to reach the state shown in FIGS. 5 and 6, the lead 9 is stopped and writing is performed.

  When writing is finished and the core 9 is separated from the paper surface 22, the protrusion 5D advances along the rear portion of the left side wall 13B of the opening groove 13A. Since the rear portion is formed substantially vertically, the connector 5 moves forward without rotating. Then, after the locking claw 5E of the connector 5 is separated from the cam teeth 7B of the rotating member 7, the protrusion 5D advances while rotating right along the front part of the left side wall 13B that is greatly inclined. However, since the coupler 5 and the rotating member 7 are separated from each other, the rotating member 7 and the chuck 1 do not rotate. Then, the protrusion 5D comes into contact with the front end of the opening groove 13A and returns to the state shown in FIG. Therefore, the lead 9 can rotate counterclockwise by a certain amount. In other words, each time writing is performed by pressing the lead 9 against the paper surface 22, the lead 9 rotates counterclockwise by a certain amount, and the lead 9 is not reduced even if writing continues.

  In the case of the first embodiment, the opening groove 13A of the inner shaft 13 and the projection 5D of the coupling tool 5 are engaged, and the locking claw 5E of the coupling tool 5 is engaged with the cam teeth 7B of the rotating member 7 within the inner shaft 13. Since the rotating member 7 is rotated counterclockwise by abutting with the rotating member 7, the mechanism for rotating the rotating member 7 is not elongated in the longitudinal direction, the sliding distance of the weight body 12 is sufficiently obtained, and the swing-out mechanical pencil is practical. Has the advantage of

  Hereinafter, the mechanical pencil according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. In addition, the same member as FIG. 1 attaches | subjects the same code | symbol, and abbreviate | omits the description. A key 103A is formed in a relative position at the front part of the core tank 103 made of synthetic resin, and an eraser 19 is attached to the inner side of the rear part of the core tank 103, and a knob 20 covering the eraser 19 is fitted on the outer side of the rear part. Further, the rotating member 107 is put on the front portion of the lead tank 103 from the front, the key 103A of the lead tank 103 is inserted into the key groove 107C of the rotating member 107, and the lead tank 103 is slid in the longitudinal direction with respect to the rotating member 107. It is configured to be movable and non-rotatable. The rear part of the chuck 1 is press-fitted and fixed to the front part of the lead tank 103.

  A chuck spring 106 is stretched with a load of about 300 g between the front end of the core tank 103 and the inner stage 5A of the connector 5, and the chuck 1 is urged rearward in the longitudinal direction.

  Next, a mechanism portion including the inner shaft 113, the core guide member 8, the connector 5, the rotating member 107, the chuck 1, the core tank 103, and the chuck spring 106 is inserted from the rear of the front shaft 23. A rear shaft 24 is detachably screwed to the front shaft 23, and a spring 18 is stretched between the washer 14 and the front end of the rear shaft 24 with a load of about 150g. The front member 16, the front shaft 23 and the rear shaft 24 constitute a main body.

  The mechanical pencil of the second embodiment described above presses the knob 20 to advance the chuck 1 to feed out the lead 9 and to follow the spare lead 9 in the lead tank 103 into the chuck 1.

  When writing is performed with the lead 9 protruding from the lead guide member 8 by a certain amount, the lead 9 is pressed against the paper surface. Then, first, the return spring 11 is compressed, and the chuck 1 moves backward together with the core 9 by a certain amount. At this time, the protrusion 5D of the connector 5 moves backward while rotating counterclockwise along the inclined right side wall of the opening groove 113A formed in the inner shaft 113.

  When the locking claw 5E of the connector 5 comes into contact with the cam teeth 107B of the rotating member 107, the rotating member 107 also rotates counterclockwise together with the connector 5. Since the rotating member 107 is in contact with the substantially hemispherical protrusion 14A of the washer 14, the frictional resistance is reduced and the rotating member 107 rotates smoothly. At this time, since the key 103A of the lead tank 103 is engaged with the key groove 107C of the rotating member 107, the chuck 1 and the lead 9 together with the rotating member 107 rotate left by a certain amount. Further, the lead 9 is retracted, the protrusion 5D is brought into contact with the rear end of the opening groove 113A, the lead 9 is stopped, and writing is performed.

  When writing is finished and the core 9 is separated from the paper surface, the protrusion 5D advances along the rear part of the left side wall of the opening groove 113A. Since the rear part of the left side wall is formed substantially vertically, the connector 5 moves forward without rotating. Then, after the locking claw 5E of the connector 5 is separated from the cam teeth 107B of the rotating member 107, the protrusion 5D advances while rotating right along the front part of the right side wall that is greatly inclined. However, since the connector 5 and the rotating member 107 are separated from each other, the rotating member 107 and the chuck 1 do not rotate. Then, the protrusion 5D comes into contact with the front end of the opening groove 113A and returns to the state shown in FIG. Therefore, the lead 9 can rotate counterclockwise by a certain amount. That is, each time writing is performed by pressing the lead 9 against the paper, the lead 9 is rotated counterclockwise by a certain amount, and the lead 9 is not reduced even if writing continues.

  In the case of the second embodiment, the rotating member 107 is rotated counterclockwise by the inner shaft 113, the connector 5 and the rotating member 107, so that the number of parts is small, the configuration is simple, and the production can be performed at low cost. Further, the pressing force for paying out the lead has an advantage of being weakened to about 300 g of the chuck spring.

  In addition, this invention is not limited to the said Example, Members, such as a shaft cylinder, an inner shaft, a rotation member, or a press member, can also integrate several members by adhering or fitting.

  A mechanism that can rotate the core by a certain amount by writing can be applied to a mechanical pencil that has a simple structure and is small in size and is incorporated in a small space.

It is sectional drawing which shows the mechanical pencil of Example 1 of this invention. (Example 1) It is an expanded sectional view which shows the AA line of FIG. (Example 1) It is an expanded sectional view which shows the BB line of FIG. (Example 1) FIG. 2 is a development view showing an engagement state between an opening groove and a protrusion and an engagement state between a locking claw and a cam tooth in FIG. 1. (Example 1) In the mechanical pencil of Example 1 of this invention, it is sectional drawing which shows the state which pressed the core against the paper surface and rotated fixed amount. (Example 1) FIG. 6 is a development view showing an engagement state between the opening groove and the protrusion and an engagement state between the locking claw and the cam tooth in FIG. (Example 2) It is sectional drawing which shows the mechanical pencil of Example 2 of this invention. (Example 2) It is an expanded sectional view which shows the AA line of FIG. (Example 2)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chuck 1A Head of chuck 1 2 Connector 4 Fastening tool 5 Connecting tool 5D Protrusion of connecting tool 5E Locking claw of connecting tool 5 6 Chuck spring 7 Rotating member 7B Cam tooth of rotating member 7 9 Core 11 Return spring 12 Weight Body 13 Inner shaft 13A Opening groove of inner shaft 13 16 Tip member 17 Pressing member 18 Spring 106 Chuck spring 107 Rotating member 107B Cam tooth 113 of rotating member 107 Inner shaft 113A Opening groove of inner shaft 113

Claims (3)

  It has a main body, a chuck built in the main body, a fastener fitted on the head of the chuck, and a chuck spring that urges the chuck rearward in the longitudinal direction, and the chuck head presses against the fastener. A mechanical pencil that holds the lead when the chuck is closed, attaches a tip member to the connector that receives the fastener, and advances the lead by advancing the chuck, and forms an opening groove on the inner shaft, One side wall of the opening groove is greatly inclined at the front part and the rear part is formed substantially vertically, and the other side wall is formed to be inclined substantially the same, and further, the connecting tool is engaged with the opening groove. And forming a locking claw at the rear end of the coupling tool, forming a plurality of cam teeth in the circumferential direction at the front end of the rotating member provided to be rotatable with respect to the inner shaft, Hold the chuck against the rotating member It is configured to be slidable in the hand direction and non-rotatable, a return spring is stretched between the coupling tool and the rotating member, and the rotating member is moved forward in the longitudinal direction by a spring having a larger loading load than the return spring. The mechanical pencil is configured such that the rotating member is pressed against the inner shaft and the locking claw of the normal connector and the cam teeth of the rotating member are appropriately separated from each other.   The mechanical pencil according to claim 1, wherein a spring is stretched between the rotating member and the pressing member.   3. The mechanical pencil according to claim 1, wherein the weight body is loosely fitted between the connector connected to the rear portion of the chuck and the pressing member, and the chuck is advanced by the inertial force of the weight body to feed out the lead.

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