JP5993199B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil capable of rotating a writing core (replacement core) by using a writing pressure and feeding out the writing core in a writing posture while holding a shaft cylinder.

As is well known, the mechanical pencil has a problem that the thickness of the drawn line changes because the writing core is reduced with the progress of writing.
Therefore, the present applicant has previously proposed a mechanical pencil equipped with a rotational drive mechanism that can gradually rotate the writing core in one direction by using the writing pressure applied to the writing core. 1 and 2 and the like.

  According to this mechanical pencil, if writing is performed with the shaft tube inclined at, for example, about 40 to 80 degrees with respect to the writing surface (paper surface), the writing core is slightly rotated in one direction each time a one-stroke character is written. Therefore, the tip of the writing core is always kept in a conical shape. This makes it possible to always write with approximately the same line width.

  On the other hand, as is well known, a mechanical pencil, such as a knocking portion protruding from the rear end portion of the shaft cylinder, is knocked out so that the writing core is fed out by a fixed amount from the tip guide member attached to the front end portion of the shaft cylinder. Act on. That is, since the lead wears with the writing operation, it is necessary to knock the knocking portion every certain writing operation.

  According to the knock type mechanical pencil described above, it is necessary to repeat the knocking operation relatively frequently every time the writing core is worn to some extent during writing. In order to perform the knocking operation, it is necessary to change the shaft cylinder in the writing posture and perform the knocking operation with the thumb or the like. Therefore, the knocking operation for the feeding operation of the lead is not only troublesome, but also reduces the writing efficiency.

International Publication No. WO2007 / 142135 JP 2009-160736 A

  This invention makes it possible to feed out the writing core in a state where the shaft cylinder is gripped in the writing posture without accompanying the above-described knocking operation for drawing out the writing core during writing, and receiving the writing pressure and It is an object of the present invention to provide a mechanical pencil capable of always writing with almost the same line width by rotating the writing core in one direction.

The basic form of the mechanical pencil according to the present invention made to solve the above-described problem is that the ball chuck that allows the writing core to advance and prevents the writing core from being retracted is accommodated in the shaft cylinder, and is held by the ball chuck. A mechanical pencil provided with a rotational drive mechanism for rotating a rotational cam in one direction in response to an axial retreat operation by a writing pressure received by a writing core and / or an axial advance operation by release of the writing pressure. The rotation drive mechanism is disposed at the rear portion in the axial direction with respect to the ball chuck, and the rotation drive mechanism is arranged on the rear end side of the ball chuck via the first relay member and the second relay member. The tip guide member of the writing core, which is connected to a rotating cam and moves relative to the ball chuck in the axial direction and has a feeding portion of the writing core, A holding chuck that is in sliding contact with the writing core is provided, and a tactile member that moves the tip guide member in the axial direction is provided, and the tip guide member is provided with a push-up operation toward the rear in the axial direction. The writing core is fed out from the tip guide member by sliding backward, and the writing core held by friction on the holding chuck is moved forward by the forward movement of the tip guide member when the push-up operation of the tactile member is released. The ball chuck configured to be pulled out from the ball chuck , the tip guide member being in contact with the first relay member, the ball chuck being attached to the first relay member, and being rotationally driven by the rotating cam. And the tip guide member supports the writing core .

In this case, it is desirable that an urging force to be pushed forward in the axial direction by a spring is applied to the tip guide member.
Moreover, the said finger member is formed in an annular | circular shape, and it can arrange | position suitably so that the outer periphery of the tip member attached to the said axial cylinder or the said axial cylinder may be employ | adopted suitably.

  Further, the tip guide member of the writing core is preferably a slider to which a tip pipe from which the writing core is fed is attached, and the holding chuck is housed in the slider immediately after the tip pipe. The

  On the other hand, the ball chuck is configured to move back and forth in the axial direction by a knocking operation of a knock portion arranged in a part of the shaft cylinder, and the gripping action of the writing core by the advancement of the ball chuck and the retraction of the ball chuck It is desirable that the writing core can be extended forward by the release action of the writing core.

  In addition, the rotating cam constituting the rotation driving mechanism is retreated in the axial direction based on the writing pressure received by the writing core, and is moved forward in the axial direction by releasing the writing pressure, and the rotating cam A cam surface is formed on each of the upper and lower surfaces orthogonal to the axial direction, and a first fixed cam surface and a second fixed cam surface are provided so as to sandwich the upper and lower cam surfaces of the rotary cam. The first fixed cam surface is engaged with the cam surface on the upper side of the rotating cam by the retreating operation of the rotating cam in the axial direction, and the rotating cam is driven to rotate in one direction, and the second fixed cam surface is The rotary cam is configured to mesh with the lower cam surface of the rotary cam by the forward movement of the rotary cam in the axial direction, and to rotate the rotary cam in the one direction.

  According to the mechanical pencil having the above-described configuration, the writing core is gradually rotated in one direction in response to the rotational driving force of the rotary cam in the rotational driving mechanism accompanying the writing operation. Thereby, it is possible to prevent the writing core from being unevenly worn as the writing progresses, and it is possible to solve the problem that the thickness of the drawn line and the darkness of the drawn line change greatly.

  Further, according to the mechanical pencil, the leading end guide member of the writing core provided with the feeding portion of the writing core moving in the axial direction relative to the ball chuck is provided, and the leading end guide member is held in sliding contact with the writing core. Since the chuck is provided and the finger member that moves in the axial direction integrally with the tip guide member is disposed outside the shaft tube or the tip member attached to the shaft tube, the finger member is moved in the axial direction. By performing the moving operation, the writing core can be fed out from the tip guide member.

  According to this, in a writing posture while holding the shaft cylinder, for example, by moving the tactile member in the axial direction with the index finger, the writing core can be extended from the tip guide member, and the writing core is extended. It is possible to continue writing without requiring the above-mentioned special knocking operation.

  Also, by applying a biasing force that pushes the tip guide member forward in the axial direction by a spring, the tactile member is pivoted by the index finger as described above in a writing posture while holding the shaft tube. By slightly pushing up toward the rear in the direction, the tip guide member can be returned to the original state by the action of the spring thereafter. By reciprocating the tip guide member in the axial direction, the writing core can be pulled out from the ball chuck by the holding chuck, and the writing core can be more easily handled.

  In addition, by adopting a configuration in which the tentacle member is formed in an annular shape and arranged so as to surround the outer periphery of the shaft tube or the tip member attached to the shaft tube, in the circumferential direction of the shaft tube Regardless of the gripping position, the same operation of the tactile member can always be ensured.

It is sectional drawing which showed the front half part of the mechanical pencil which concerns on this invention. It is sectional drawing which showed the latter half part similarly. It is the perspective view which fractured | ruptured and showed the front half part similarly. Furthermore, it is the perspective view which expanded and showed the front-end | tip part. It is the expanded sectional view which showed the structure of the rotational drive mechanism. It is a schematic diagram for explaining the rotational drive action of the rotary cam provided in the rotational drive mechanism step by step. It is a schematic diagram explaining the rotational drive action of the rotating cam following FIG.

  An embodiment of a mechanical pencil according to the present invention will be described with reference to the drawings. In the drawings shown below, the same parts are denoted by the same reference numerals. However, in some drawings, the representative parts are indicated by reference numerals for the sake of space, and the detailed configuration is shown in the other drawings. Each reference will be described with reference to the reference numerals.

  1, 3, and 4 showing the front half of the mechanical pencil, reference numeral 1 denotes a shaft cylinder constituting the outline of the mechanical pencil, that is, a front shaft, and a tip portion is formed on the inner peripheral surface of the front end portion of the front shaft 1. The front end 2 is detachably attached to the front shaft 1 by screwing 2 together.

  The lip portion 2 is configured so that the inner diameter becomes stepped toward the front, and a slider 3 that functions as a tip guide member of the writing core is slidable in the axial direction inside the tip portion 2, and the shaft rotates. It is housed as possible. The slider 3 is also configured to have a stepped outer diameter toward the front, and the tip portion 3a of the slider 3 is formed in a columnar shape, and is formed in a cylindrical shape at the front end portion of the lip portion 2. It is accommodated in a state protruding from the formed hole.

A tip end pipe 4 for guiding the writing core L is attached to the cylindrical tip end portion 3 a of the slider 3, and the slider 3 and the tip pipe 4 constitute a tip guide member for the writing core.
Further, immediately after the tip pipe 4 in the internal space of the slider 3, a rubber holding chuck 5 having a through hole formed in the center is accommodated, and the through hole of the holding chuck 5 serves as the writing core L. The writing core is slidably brought into contact with the peripheral surface of the tape to temporarily hold the writing core by friction.

  That is, in this embodiment, the leading end guide member of the writing core by the leading end pipe 4 as the feeding portion of the writing core L and the slider 3 that supports the leading end pipe 4 is provided with a holding chuck 5 that is in sliding contact with the writing core L. The holding chuck 5 is in sliding contact with the peripheral surface of the writing core L.

A ring member 6 having a projecting portion 6a that is formed in a ring shape and partially protrudes toward the peripheral surface side is loosely fitted to the slider 3 so that the slider 3 is capable of rotating the shaft. An annular tactile member 7 arranged so as to cover a part of the peripheral surface of the lip portion 2 is attached to a protruding portion 6 a that protrudes to the peripheral surface side of 6.
That is, the protruding portion 6a protruding to the peripheral surface side of the ring member 6 is disposed so as to enter the groove portion 2a formed in the axial direction in the tip portion 2 and move in the axial direction as shown in FIG. The ring member 6 is loosely fitted to the slider 3 capable of rotating the shaft with a slip.

Accordingly, the ring member 6 can slide the slider 3 toward the rear in the axial direction by performing an operation of pushing the annular tactile member 7 rearward in the axial direction with a fingertip or the like. .
In this case, the configuration is such that the finger member 7 is formed in an annular shape so as to surround the outer periphery of the mouthpiece member 2, so that regardless of the gripping position in the circumferential direction of the shaft tube It is always possible to guarantee the same operation of the finger member.

A ball chuck 9 that holds the writing core L is disposed in the internal space of the slider 3. The ball chuck 9 is formed in a cylindrical shape and has a fastener 10 having a tapered surface whose inner peripheral surface expands forward, and the ball chuck 9 is accommodated in the fastener 10 and includes the writing core L along the axis. A through hole is formed, and a tip end portion thereof is divided into a plurality of portions along the axial direction, and is disposed between the outer peripheral surface of the chuck main body portion 11 and the inner peripheral surface of the fastener 10. The plurality of balls 12 are provided.
An annular stopper member 13 that prevents the chuck main body portion 11 from moving forward more than a predetermined amount and prevents the ball 12 from falling off is fitted into the inner peripheral surface of the front end portion of the fastener 10. It is.

Accordingly, when the writing pressure is applied to the writing core L, the ball chuck 9 is in contact with the tapered surface of the cylindrical fastener 10 together with the ball 12 so that the writing core L is chucked. It is gripped by the main body 11. Thereby, the retraction of the writing core L in the ball chuck 9 is prevented.
On the other hand, when the force for pulling the writing core L forward is applied, the chuck body 11 is not affected by the fastener 10 and therefore the writing core L can be pulled forward with relatively little resistance. That is, the ball chuck 9 acts to allow the writing core L to move forward and prevent it from moving backward.

The chuck body 11 is formed to have a large diameter at the rear end portion with a reduced outer diameter at the central portion in the length direction.
A coiled spring 14 is disposed so as to surround the central portion of the chuck body 11 in the length direction, and a front end of the spring 14 is formed on a step formed on the inner peripheral surface of the fastener 10. The rear end of the spring 14 is in contact with the large diameter portion on the rear end side of the chuck body 11.

  Accordingly, the spring 14 acts to urge the chuck body portion 11 backward by an axially expanding action, whereby the ball chuck 9 is held in a state of gripping the writing core L. Therefore, the spring 14 is referred to as a chuck spring for convenience.

The slider 3 is configured to be slidable in the axial direction with respect to the outer peripheral surface of the fastener 10 constituting the ball chuck 9, and the fastener 10 is formed in a cylindrical shape on the rear end side. The first relay member 16 is fitted and attached to the inner peripheral surface. The first relay member 16 is fitted and attached to the inner peripheral surface of a second relay member 17 formed in a cylindrical shape at a substantially central portion in the length direction.
A short shaft-shaped relay pipe 18 formed of a flexible material, for example, synthetic resin, is connected to the inner peripheral surface of the rear end portion of the second relay member 17. Is connected to a rotation drive mechanism described later.

  The second relay member 17 described above has a slightly thick inner diameter on the front end side, and covers the rear end of the slider 3 so that it can slide. A spring 20 is accommodated in a space between the front end portion of the relay member 17 having a slightly thick inner diameter and the first relay member 16 described above. That is, the spring 20 acts to push the slider 3 forward, and the spring 20 is called a slider pushing spring for convenience.

  On the other hand, a cylindrical body 22 having a through hole for the writing core L is slidably accommodated in the space on the rear end side of the first relay member 16 described above. A core case 23 is fitted and attached to the rear end portion of the cylindrical body 22, and the front end portion of the cylindrical body 22 is attached to the chuck body as the core case 23 moves forward by a knocking operation described later. It abuts on the portion 11 and acts to push the chuck body portion 11 forward. Therefore, the cylindrical body 22 is referred to as a knock transmission cylinder for convenience.

Further, on the front end portion side of the second relay member 17 described above, a step portion 17a made by forming the inner diameter slightly thick, and an inner peripheral surface on the rear end portion side of the front shaft 1 are formed. A weight 24 by a coil spring is accommodated in the axial space between the reduced diameter portion 1a so as to be movable in the axial direction.
The weight 24 by the coil spring works so that the inertia force of the weight 24 when the shaft cylinder is swung in the axial direction pushes the second relay member 17 forward, as will be described later. The chuck 9 acts to instantaneously move forward.

  In the configuration of the rear half of the mechanical pencil shown in FIG. 2, the rear shaft 25 constituting the shaft cylinder is fitted and attached to the rear end portion of the front shaft 1 described above. An outer shaft 26 integrally formed with a clip portion 26a is attached so as to cover the outer side of the rear shaft 25, and the outer shaft 26 is a retaining ring screwed to the rear end portion of the rear shaft 25. 27 is attached.

A rotation drive mechanism 29 is accommodated in the internal space of the rear shaft 25. The rotation drive mechanism 29 is unitized, and the rear end portion of the short shaft-shaped relay pipe 18 formed of the above-described synthetic resin is connected to the rotation drive mechanism 29.
As shown in FIG. 2, the rotational drive mechanism 29 is pressed rearward by a shaft spring 30 interposed between the rear end portion of the front shaft 1, and the diameter of the rear shaft 25 is reduced. The formed step portion 25 a is pressed against the urging force of the shaft spring 30. Thereby, the rotation drive mechanism 29 is fixed in the rear shaft 25.
The configuration and operation of the rotary drive mechanism 29 will be described later in detail with reference to FIGS.

In the rear end portion of the rear shaft 25, a knock bar 31 as a knock member is attached to be slidable in the axial direction with respect to the rear shaft 25, and a space portion between the rear shaft 25 and the knock bar 31 is provided. A knock bar return spring 32 is arranged.
A partition wall 31 a having a writing core replenishing hole is formed slightly closer to the rear end than the center of the knock bar 31. An eraser 33 is detachably attached to the rear end portion of the knock bar 31, and a knock cover 34 covering the eraser 33 is detachably attached to the peripheral surface of the rear end portion of the knock bar 31.
A short shaft cylindrical member 35 is attached to the rear end portion of the core case 23. When the knock cover 34 is knocked, the partition wall portion 31a of the knock bar 31 moves the cylindrical member 35 forward. The lead case 23 also moves forward in accordance with this.

As a result, the knock transmission cylindrical body 22 attached to the front end portion of the core case 23 moves forward, and the step portion 22a formed on the rear end side of the cylindrical body 22 is connected to the rear end of the first relay member 16. The first relay member 16 is moved forward by contacting the portion.
The first relay member 16 and the second relay member 17 are attached by fitting as described above, and the second relay member 17 is also moved forward by the advancement of the first relay member 16, and the distal end portion of the second relay member 17 is moved forward. Comes into contact with the rear end portion of the mouth portion 2.

Until this state is reached, the chuck main body 11 is not opened and moves forward while holding the writing core L, and acts so that the writing core L is fed out from the tip pipe 4.
Further, when the cylindrical body 22 moves forward by continuing the knocking operation, the front end portion of the cylindrical body 22 comes into contact with the rear end portion of the chuck main body 11, and the chuck main body 11 is opened and the forward movement is performed.
When the knocking operation is released, the knocking bar 31 is retracted by the action of the return spring 32 and returns to the state shown in FIG.

At this time, the chuck body 11 is retracted by the action of the chuck spring 14, but the writing core L is held by the friction of the holding chuck 5 accommodated in the slider 3, so that the chuck body 11 is retracted. Regardless of the operation, the writing core L is pulled out from the chuck body 11 and maintained in a state where it is drawn out from the tip pipe 4. Therefore, each time the knocking operation described above is repeated, the writing core L can be fed out by a predetermined amount.
Further, by maintaining the knock cover 34 in the knocked state, the chuck body 11 releases the gripping of the lead L, so that the writing lead L in a state of being fed out from the tip pipe 4 can be pushed back with a fingertip or the like. .

In the mechanical pencil described above, a rotational drive mechanism 29 is accommodated in the rear shaft 25 as shown in FIG.
The rotation drive mechanism 29 is provided with a rotating cam and receives an axial retreat operation by the writing pressure received by the writing core L held by the ball chuck 9 and an axial advance operation by releasing the writing pressure. Thus, the rotary cam is driven to rotate in one direction.

  That is, when the writing core L receives a writing pressure, the chuck body 11 shown in FIGS. 1, 3, and 4 slightly retracts, and the fastener 10 also retracts via the ball 12. A first relay member 16, a second relay member 17, and a relay pipe 18 are connected to the fastener 10, and a retraction operation and a forward operation (hereinafter referred to as cushioning) of the writing core L when receiving a writing pressure. Is also transmitted to the rotary drive mechanism 29 described above via each member.

  FIG. 5 is a sectional view showing the entire configuration of the rotation drive mechanism 29. The relay pipe 18 shown in FIG. 5 is coaxially arranged so as to cover the core case 23, and the relay pipe 18 rotates the retraction and forward movement (cushion movement) of the writing core based on the writing movement. In addition to being transmitted to the drive mechanism 29, it acts to transmit the rotational motion of the rotary cam in the rotational drive mechanism 21 generated by the cushion operation to the ball chuck 9, the slider 3, etc. via the relay pipe 18.

The rotation drive mechanism 29 is provided with a rotation cam 40 formed in a cylindrical shape. The relay pipe 18 is fitted to the inner peripheral surface of the rotation cam 40 at the front end portion of the rotation drive mechanism 29. Are combined.
The rotary cam 40 has a large-diameter portion with a slightly larger diameter in the vicinity of the front end portion, and a first cam surface 40a is formed on one end surface (rear end surface) of the large-diameter portion. A second cam surface 40b is formed on the other end surface (front end surface).

  On the other hand, a cylindrical first cam forming member (also referred to as an upper cam forming member) 41 is arranged to rotatably hold the rotating cam 40 so as to cover the rear end side of the rotating cam 40. On the outer periphery of the front end portion of the upper cam forming member 41, a cylindrical second cam forming member (also called a lower cam forming member) 42 is fitted and attached to the upper cam forming member 41. .

  A fixed cam surface (also referred to as a first fixed cam surface) 41 a is formed on the front end surface of the upper cam forming member 41 that faces the first cam surface 40 a of the rotating cam 40. A fixed cam surface (also referred to as a second fixed cam surface) 42 a is formed on the inner surface of the front end portion of the lower cam forming member 42 facing the second cam surface 40 b of the rotating cam 40.

  Regarding the relationship between the first and second cam surfaces 40a, 40b formed on the rotating cam 40, the first fixed cam surface 41a, and the second fixed cam surface 42a and their interaction, Details will be described later with reference to FIGS.

  As shown in FIG. 5, a cylinder member 44 is fitted on the rear end side of the upper cam forming member 41 described above, and an insertion hole 44a through which the core case 23 can be inserted into the rear end portion of the cylinder member 44. Is formed. A torque canceller 45 formed in a cylindrical shape and movable in the axial direction is disposed in the cylinder member 44, and a front end of the inner peripheral surface of the torque canceller 45 and a rear end of the inner peripheral surface of the cylinder member 44 are arranged. A coiled cushion spring 46 is mounted between them.

The cushion spring 46 acts to urge the torque canceller 45 forward. The cushion cam 46 is pushed by the torque canceller 45 receiving the urging force, and the rotating cam 40 acts forward.
The rotation drive mechanism 29 is formed in a space through which the core case 23 passes and is isolated from the core case 23. The rotation drive mechanism 29 is united by the members indicated by the reference numerals 40 to 46 as a unit. Has been.

  According to the configuration of the rotation drive mechanism 29 described above, the rotation cam 40 is connected to the ball chuck via the relay pipe 18, the second relay member 17, and the first relay member 16 while the ball chuck 9 grips the writing core L. 9. Along with the slider 3, it is rotatable about the axis. When the mechanical pencil is in a state other than the writing state, the rotary cam 40 is biased forward via the torque canceller 45 by the action of the cushion spring 46.

  On the other hand, when writing is performed with a mechanical pencil, that is, when a writing pressure is applied to the writing core L protruding from the tip pipe 4, the ball chuck 9 is slightly retracted against the urging force of the cushion spring 46. As a result, the rotary cam 40 is also retracted in the axial direction. Therefore, the first cam surface 40a formed on the rotary cam 40 shown in FIG. 5 is joined to the first fixed cam surface 41a to be engaged.

6 (A) to 6 (C) and FIGS. 7 (D) and 7 (E) explain the basic operation of the rotation drive mechanism 29 for rotating the rotation cam 40 by the operation described above in order.
6 and 7, reference numeral 40 schematically shows the rotary cam described above, and one end face (the upper face in the figure) is continuously serrated along the circumferential direction. The first cam surface 40a is formed in an annular shape. Similarly, a second cam surface 40b that is continuously serrated along the circumferential direction is formed in an annular shape on the other end surface (the lower surface in the figure) of the rotating cam 40.

  On the other hand, as shown in FIGS. 6 and 7, the first fixed cam surface 41 a continuously formed in a sawtooth shape along the circumferential direction is also formed on the annular end surface of the upper cam forming member 41, A second fixed cam surface 42 a that is continuously serrated along the circumferential direction is also formed on the annular end surface of the lower cam forming member 42.

  Then, the first cam surface 40a formed on the rotating cam 40, the second cam surface 40b, the first fixed cam surface 41a formed on the upper cam forming member 41, and the first cam surface formed on the lower cam forming member 42. The cam surfaces formed in a sawtooth shape along the circumferential direction of the two fixed cam surfaces 42a are formed so that their pitches are substantially the same. 6 and 7, the ◯ mark drawn at the center of the rotating cam 40 indicates the rotational movement state of the rotating cam 40.

FIG. 6A shows the relationship between the upper cam forming member 41, the rotating cam 40, and the lower cam forming member 42 when the mechanical pencil is not in the writing state, that is, when no writing pressure is applied. In this state, the second cam surface 40b formed on the rotating cam 40 abuts against the second fixed cam surface 42a side of the lower cam forming member 42 by the urging force of the cushion spring 46 shown in FIG. Has been.
At this time, the first cam surface 40a on the rotating cam 40 side and the first fixed cam surface 41a are set so as to have a half-phase (half-pitch) offset with respect to one tooth of the cam in the axial direction. ing.

  FIG. 6B shows an initial state in which the writing pressure is applied to the writing core L by using the mechanical pencil. In this case, the rotary cam 40 retracts in the axial direction by contracting the cushion spring 46 via the ball chuck 9 and the relay pipe 18. Thereby, the rotating cam 40 moves to the upper cam forming member 41 side.

FIG. 6C shows a state in which writing pressure is applied to the writing core L by using a mechanical pencil, and the rotating cam 40 is in contact with the upper cam forming member 41 side. In this case, the rotating cam 40 is formed on the rotating cam 40. The first cam surface 40a thus engaged meshes with the first fixed cam surface 41a on the upper cam forming member 41 side. As a result, the rotating cam 40 receives rotational driving corresponding to a half phase (half pitch) of one tooth of the first cam surface 40a.
In the state shown in FIG. 6C, the second cam surface 40b on the rotating cam 40 side and the second fixed cam surface 42a 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 with respect to the writing core L is released. In this case, the rotary cam 40 is operated by the action of the cushion spring 46 described above. Moves forward in the axial direction. Thereby, the rotating cam 40 moves to the lower cam forming member 42 side.

  Further, FIG. 7E shows a state in which the rotating cam 40 is in contact with the lower cam forming member 42 side by the action of the cushion spring 46 described above. In this case, the second cam formed on the rotating cam 40 is shown in FIG. The cam surface 40b meshes with the second fixed cam surface 42a on the lower cam forming member 42 side. As a result, the rotating cam 40 again receives rotational driving corresponding to one half phase (half pitch) of one tooth of the second cam surface 40b.

Therefore, as indicated by the circles drawn at the center of the rotating cam 40, the rotating cam 40 receives the first and second cam surfaces 40a, A rotational drive corresponding to one tooth (one pitch) of 40b is received.
As a result, the writing core L held by the ball chuck 9 via the relay pipe 18, the second relay member 17, and the first relay member 16 is also rotationally driven together with the slider 3.

  In the rotational drive mechanism 29 shown in FIG. 5, the cylindrical torque canceller 45 that pushes the rotating cam 40 forward by receiving the urging force of the coil-shaped cushion spring 46 has the front end face of the torque canceller 45 and the rotation A slip is generated between the rear end surface of the cam 40 and the rotational motion of the rotary cam 40 is prevented from being transmitted to the cushion spring 46.

  In other words, the torque canceller 45 is interposed between the rotary cam 40 and the cushion spring 46, so that the rotational motion of the rotary cam 40 is transmitted to the cushion spring 46 by the sliding action described above. Acts to prevent. As a result, it is possible to solve the problem that the torsional return (spring torque) of the spring 46 is generated and the rotation operation of the rotating cam 40 is obstructed.

According to the mechanical pencil provided with the writing core rotation drive mechanism 29 described above, the tip of the writing core L gripped by the ball chuck 9 is always formed in a conical shape due to the rotational movement received by the ball chuck 9 and the wear caused by the writing. . Therefore, it is possible to prevent the writing core L from being unevenly worn as the writing proceeds , and writing with a stable line width becomes possible.

  In addition, in the mechanical pencil having the above-described configuration, a holding chuck 5 is provided on a tip guide member composed of a slider 3 and a tip pipe 4 that move relative to the ball chuck 9 in the axial direction. Since the urging force to be pushed out in the axial direction is given by the spring 20, the tip pipe 4 gradually recedes together with the slider 3 when the writing core L is worn as the writing progresses.

At the moment when the writing pressure is released, the tip guide member by the slider 3 and the tip pipe 4 moves forward by the action of the spring 20, so that the holding chuck 5 arranged on the slider 3 also moves forward, whereby the writing core L is Pulled out from the ball chuck 9.
Therefore, the writing core corresponding to the amount worn by writing is automatically drawn out, and writing can be continued without specially knocking the knock cover 34 to feed out the writing core L. Thus, the operational effects described in the column of the effect of the invention described above can be obtained.

  In this embodiment, an annular tactile member 7 is attached so as to cover a part of the peripheral surface of the lip portion 2, and the tactile member 7 is moved rearward in the axial direction with a fingertip or the like. By performing the push-up operation, the slider 3 can be slid rearward. After the push-up operation of the finger member 7, the slider 3 moves forward by the action of the spring 20, so that the writing core L held by the holding chuck 5 by friction is pulled out from the ball chuck 9.

Therefore, according to this embodiment, the writing core L can be extended also by operating the tactile member 7 described above.
In addition, in this embodiment, the tactile member 7 is disposed in the vicinity of the lip portion 2, so that the tactile member 7 is axially moved by, for example, the index finger in a writing posture while holding the shaft cylinder. By slightly pushing up, the writing core L can be fed out from the tip pipe 4, and writing can be continued without reducing efficiency.

Further, in the mechanical pencil having this configuration, the weight 24 is accommodated in the shaft cylinders 1 and 25, and the second relay member 17 is moved forward by the inertia force of the weight 24 by shaking the shaft cylinder in the axial direction. It works to push out, and as a result, it acts to momentarily advance the ball chuck 9 described above.
Therefore, relative movement between the slider 3 provided with the holding chuck 5 and the ball chuck 9 is caused by the momentary forward movement of the ball chuck 9 and the return movement by the spring 20, thereby causing the writing core L to move. It can be fed out from the tip pipe 4.

  Therefore, according to the embodiment of the mechanical pencil described above, it is possible to realize four types of operations including the operation of knocking the knock cover 34 as described above in the feeding operation of the writing core L, and the user can Depending on the time and case, it is possible to select the optimum feeding operation of the writing core L.

In the embodiment described above, in the rotational drive mechanism 29 that rotationally drives the rotational cam, the retraction operation in the axial direction of the rotating cam 40 and the writing pressure by the writing pressure received by the writing core L gripped by the ball chuck 9. Each of the rotating cams is rotated in one direction in response to the forward movement of the rotating cam 40 in the axial direction due to the release.
However, this may be configured to rotate the rotating cam in one direction only during the retreating operation in the axial direction of the rotating cam by the writing pressure received by the writing core, and the shaft of the rotating cam by releasing the writing pressure. Even if the rotary cam is configured to rotate in one direction only during the forward movement in the direction, the same effect can be obtained.

In the rotation drive mechanism 29 in the above-described embodiment, a large number of cam surfaces 40 a and 40 b that are continuous in an annular shape are formed on the upper and lower surfaces orthogonal to the axial direction of the rotation cam 40, and the rotation cam 40 The first and second fixed cam surfaces 41a and 42a arranged to face each other so as to sandwich the upper and lower cam surfaces are also configured such that a large number of cam surfaces continuous in an annular shape are formed.
However, either one of the upper cam surface 40a of the rotating cam 40 or the first fixed cam surface 41a disposed opposite thereto is formed with a large number of continuous cam surfaces, and the other is a small number of cam surfaces. A similar effect can be obtained even in a configuration in which the above is formed at one place or intermittently.

Similarly, a large number of continuous cam surfaces are formed on either the lower cam surface 40b of the rotating cam 40 or the second fixed cam surface 42a disposed opposite thereto, and the other is a small number. The same effect can be obtained even in a configuration in which the cam surface is formed at one place or intermittently.
In short, a configuration in which a large number of continuous cam surfaces are formed on one of the opposing rotating cam side and fixed cam side, and the other is formed with a small number of cam surfaces that mesh with a part of the continuous many cam surfaces. Even if it is adopted, the same effect can be obtained.

  Further, the tactile member 7 capable of performing the operation of drawing out the writing core L from the tip pipe 4 is formed in an annular shape so as to surround the lip portion 2 attached to the tip portion of the shaft cylinder (tip shaft 1). Although arranged, the tactile member 7 can adopt a configuration such as a rectangular shape in addition to the annular shape, and the same effect can be obtained even when the tactile member 7 is arranged on the side surface of the shaft tube. Can be expected.

1 Lead shaft (shaft tube)
2 Mouth part 2a Groove part 3 Slider (tip guide member)
3a Slider tip 4 Tip pipe (tip guide member)
DESCRIPTION OF SYMBOLS 5 Holding chuck 6 Ring member 6a Peripheral surface side protrusion part 7 Tactile finger member 9 Ball chuck 10 Fastening tool 11 Chuck body part 12 Ball 14 Chuck spring 16 1st relay member 17 2nd relay member 18 Relay pipe 20 Spring for slider extrusion 22 Knock transmission cylinder 23 Core case 24 Weight 25 Rear shaft (shaft tube)
25a Step part 26 Outer shaft 26a Clip part 29 Rotation drive mechanism 30 Shaft spring 32 Return spring 33 Eraser 34 Knock cover 40 Rotating cam 40a First cam surface (upper cam surface)
40b Second cam surface (lower cam surface)
41 Upper cam forming member (first fixed cam forming member)
41a First fixed cam surface 42 Lower cam forming member (second fixed cam forming member)
42a Second fixed cam surface 44 Cylinder member L Writing core

Claims (6)

A ball chuck that allows the writing core to move forward and prevents retraction is housed in the shaft cylinder, and the shaft is retracted in the axial direction by the writing pressure received by the writing core held by the ball chuck and / or the shaft is released from the writing pressure. A mechanical pencil provided with a rotational drive mechanism that receives a forward movement in a direction and rotationally drives the rotary cam in one direction,
The rotation drive mechanism is disposed at a rear portion in the axial direction with respect to the ball chuck, and the rotation drive mechanism rotates on the rear end side of the ball chuck via the first relay member and the second relay member. Connected to the cam,
The tip guide member of the writing core, which is relatively moved in the axial direction with respect to the ball chuck and has a feeding portion of the writing core, is provided with a holding chuck that is slidably contacted with the writing core, and the tip guide member is pivoted. A tactile member that moves in a direction is provided,
By giving a push-up operation toward the rear in the axial direction to the tactile member, the tip guide member is slid rearward so that the writing core is fed out from the tip guide member and the push-up operation of the tactile member is released. In the forward movement of the tip guide member, the writing core held by friction on the holding chuck is drawn out from the ball chuck ,
The tip guide member is in contact with the first relay member, the ball chuck is attached to the first relay member, and the writing is performed by the ball chuck and the tip guide member that are rotationally driven by the rotating cam. Mechanical pencil characterized by supporting the core .   2. The mechanical pencil according to claim 1, wherein the tip guide member is provided with an urging force to be pushed forward in the axial direction by a spring.   The said finger member is formed in an annular | circular shape, and is arrange | positioned so that the outer periphery of the tip member attached to the said axial cylinder or the said axial cylinder may be enclosed. Mechanical pencil.   The tip guide member of the writing core is a slider to which a tip pipe from which the writing core is fed is attached, and the holding chuck is accommodated in the slider immediately after the tip pipe. The mechanical pencil according to any one of claims 1 to 3.   The ball chuck is configured to move back and forth in the axial direction by a knocking operation of a knock portion arranged in a part of the shaft cylinder, and the writing core gripping action by the advancement of the ball chuck and the writing by the retraction of the ball chuck The mechanical pencil according to any one of claims 1 to 4, wherein the writing core can be drawn forward by a releasing action of the lead.   The rotating cam constituting the rotation driving mechanism is retracted in the axial direction based on the writing pressure received by the writing core, and is moved forward in the axial direction by releasing the writing pressure, and the axial direction of the rotating cam A cam surface is formed on each of the upper and lower surfaces orthogonal to each other, and a first fixed cam surface and a second fixed cam surface arranged to face each other so as to sandwich the upper and lower cam surfaces of the rotating cam are provided, The first fixed cam surface is engaged with the cam surface on the upper side of the rotating cam by the retreating operation of the rotating cam in the axial direction to drive the rotating cam to rotate in one direction, and the second fixed cam surface is the rotating cam. 6. The rotating cam is driven to rotate in the one direction by meshing with a lower cam surface of the rotating cam by a forward movement in the axial direction. Made Pupenshiru.

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