JP5412144B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil in which a lead core in a shaft cylinder is extended.

Conventionally, this type of mechanical pencil, like the one described in Patent Document 1, is operated by knocking a knock member (knob 7) on the rear end side, whereby the front end portion (base 10) of the shaft tube (9). In general, a lead core (core 8) is fed out from the core.
The structure of this prior art will be described in more detail. As the knock member (knob 7) advances, the chuck (2) holding the lead core (core 8) inside the shaft cylinder (9) advances, The chuck (2) disengages from the annular fastener (3) after a predetermined amount of advance and releases the lead core (core 8).

However, according to the conventional mechanical pencil, when the lead core (core 8) is protruded too much, the lead core (core) is maintained while pressing the knock member (knob 7) to keep the chuck (2) open. After the lead core was retracted, for example, by pressing the front end of 8) against the writing surface, the knock member (knob 7) had to be knocked again, which was troublesome.
In addition, when the lead core (core 8) is completely consumed or broken during writing, it is necessary to change the writing instrument to knock the knock member (knob 7) on the rear end side of the shaft tube (9). It was.

JP 2007-301914 A

  The present invention has been made in view of the above-described conventional circumstances, and a problem to be solved by the present invention is to provide a mechanical pencil in which a lead core can be protruded only by a fixed amount by an operation in a writing posture without being changed. There is to do.

The technical means for solving the above problems is a mechanical pencil comprising a shaft cylinder, a lead core feeding mechanism for feeding out the lead core by a backward movement and a forward movement relative to the shaft cylinder, and an urging member. The lead core feeding mechanism is moved backward by the backward pressing force applied to the lead core, and the lead core feeding mechanism is moved forward by the biasing force of the biasing member when the pressing force is released. It is characterized by that.
According to this configuration, when a backward pressing force is applied to the lead core, the lead core feeding mechanism performs a retreat operation relative to the shaft tube by the pressing force. And if the said pressing force is cancelled | released, the lead lead feeding mechanism will carry out the advance operation | movement facing a shaft cylinder with the urging | biasing force of an urging | biasing member. Therefore, the lead lead feeding mechanism feeds the lead lead by the backward movement and the forward movement.

In a further technical means, the lead lead feeding mechanism releases the lead lead in the lead lead feeding direction, and holds and holds the lead lead with a holding force capable of withstanding the pen pressure in the lead lead immersion direction. When a force greater than the writing pressure is applied to the lead core from the front side, the chuck mechanism that releases the holding force is provided on the front side of the chuck mechanism, and is movable back and forth. A lead core holding mechanism formed to hold the lead core with a predetermined holding force, and the biasing member is provided to bias the chuck mechanism and the lead core holding mechanism in the separating direction. has been, it shall be the Son and of the features.
According to this configuration, when a force larger than the writing pressure is applied to the lead core from the front side, the chuck mechanism is released. Therefore, the lead core moves backward with respect to the chuck mechanism. Along with this retreat, the lead core holding mechanism holding the lead core moves backward against the biasing force of the biasing member.
When the force from the front side with respect to the lead core is removed, the lead core holding mechanism is urged by the urging member while holding the lead core, and moves forward relative to the chuck mechanism. Therefore, the lead core advances with the advancement of the lead core holding mechanism.

In a further technical means, the lead core feeding mechanism is provided so as to advance and retract by a predetermined amount within the shaft cylinder, and when it moves forward, the lead core is clamped so as not to be retractable and advanceable to a predetermined release position. When retreating, the chuck mechanism that releases the lead core and the lead core that is fed out from the chuck mechanism are inserted and guided forward, and can move forward and backward by a predetermined amount relative to the shaft cylinder, and is pulled by the chuck mechanism. The tip guide member provided to retreat and the lead core are held with a force weaker than the clamping force of the chuck mechanism, and are provided to advance and retract between the tip guide member and the chuck mechanism. A lead core holding mechanism and a retreat interlocking means for retreating the lead core holding mechanism relative to the tip guide member in conjunction with the retraction of the tip guide member, wherein the biasing member includes the chuck. A first urging member that urges the mechanism forward against the shaft cylinder and a second urging member that urges the lead core holding mechanism forward against the chuck mechanism. And
According to this configuration, for example, when the lead core protruding from the tip guide member is pressed and retracted, the chuck mechanism that holds the lead core together with the lead core also resists the biasing force of the first biasing member. And retreat. Then, the tip guide member is also retracted by being pulled by the chuck mechanism.
As the tip guide member is retracted, the retract interlocking means retracts the lead core holding mechanism relative to the tip guide member.
When the lead core holding mechanism is retracted, the holding force of the lead core holding mechanism is weaker than the clamping force of the chuck mechanism, so that the lead core holding mechanism moves backward while sliding against the lead core.
When the lead lead is further retracted, the chuck mechanism retracted by a predetermined amount together with the lead lead becomes the release position, and the chuck mechanism releases the lead lead. Therefore, the lead core can be retracted.
When the lead core is further pressed, the lead core is released from the chuck mechanism, and therefore slides and moves backward with respect to the tip guide member, the lead core holding mechanism, and the chuck mechanism.
In this released state, when the pressing force from the front with respect to the lead core is removed, the chuck mechanism is advanced by the biasing force of the first biasing member, and the lead core holding mechanism is biased by the second biasing member. To move forward relative to the chuck mechanism.
As the lead core holding mechanism advances, the lead core held by the lead core holding mechanism also advances. At this time, since the lead core can be advanced while being sandwiched by the chuck mechanism, the advancement of the lead core is not hindered by the chuck mechanism.
The lead core holding mechanism moves forward until it comes into contact with the tip guide member, and the lead core that moves forward together with the lead core holding mechanism moves forward even relative to the tip guide member, so that the lead core is fed out from the front end of the tip guide member.

In a further technical means, the retraction interlocking means includes a first inclined a first protrusion provided on one of said the barrel front guide member, provided on the other of the rear oblique circumferential direction as an inclined portion, and a second protrusion provided on one of the said front guide member the lead core holding mechanism, a second inclined portion which is provided on the other of the inclined rearwards obliquely opposite circumferential direction The lead core holding mechanism is engaged with the shaft cylinder so that the lead core holding mechanism can be advanced and retracted and cannot rotate, and the first convex portion and the first inclined portion are engaged with each other to retract relative to the shaft cylinder. It is rotated together with the front guide member in its retracted, by the engagement of the second protrusion and the second inclined portion, and the lead core holding mechanism to retract relative to the distal guide member It is characterized by that.
The recess includes a through hole and a bottomed hole.
According to this configuration, as the tip guide member moves backward, the tip guide member rotates due to the engagement between the first convex portion and the first inclined portion. Along with the rotation of the front guide member, by the engagement of the second protrusion and the second inclined portion, the lead core holding mechanism is moved backward relative to the front guide member.

In a further technical means, the lead core holding mechanism includes a slide portion for movably engaged with front guide member, the elastic contact portion which is elastically pressed against the outer peripheral surface of the lead core in the sliding portion It is characterized by the following.
According to this configuration, the slide portion as well as forward and backward relative to the front guide member, the elastic contact portion is held by an appropriate pressing force to the outer peripheral surface of the lead core.

According to a further technical means, the chuck mechanism is capable of advancing and retracting in a shaft cylinder, and is provided with a substantially cylindrical sleeve provided to be urged forward by the first urging member, and the second attachment. A chuck portion that is urged rearward by the biasing member and fits from the front side of the sleeve to reduce the diameter and sandwiches the lead core, and is provided so as not to be able to advance and retreat relative to the chuck portion and is retracted by a predetermined amount And an abutting portion that abuts on the chuck portion and loosens the clamping state of the chuck portion.
According to this configuration, when the sleeve and the chuck part are retracted by a predetermined amount and the chuck part comes into contact with the contact part, the chuck part moves forward relative to the sleeve and loosens.

According to a further technical means, a knock member provided so as to be able to advance and retract by a predetermined amount with respect to the shaft cylinder in a state where the operation portion is exposed from the rear end portion of the shaft cylinder or the outer peripheral portion of the shaft cylinder, and and a three biasing member, to form the contact portion at the front end of the knocking member, characterized in that the lead core from the tip guide member by advancing and retracting the knock member is to be paid out.
According to this configuration, when the knock part is advanced by a pressing operation to the operation part, the contact part on the front end side of the knock part comes into contact with the chuck part, and the chuck part advances relative to the substantially cylindrical sleeve. Relax.

Since the present invention is configured as described above, the following effects can be obtained.
And if the front guide member are too protruding lead core, when lead core projecting from the leading end guide member is too short, when該鉛core is front and flush front guide member, the Namarishin and the like pressed against the strong writing surface, in addition a pressing force to該鉛core, after retracting the該鉛core, if releasing the pressing force, quantitative projecting該鉛wick from the front end of the front guide member To do.
Therefore, it is possible to make the lead core protrude by a certain amount by the operation in the writing posture without changing it, and as a result, when the protruding amount of the lead core is too long or too short, When the lead is exhausted or broken, the lead core can be easily protruded by a fixed amount.

It is a longitudinal cross-sectional view of the mechanical pencil which shows an example of the mechanical pencil concerning this invention. It is a cross-sectional view which shows the cross section which follows the (II)-(II) line | wire in FIG. 1 about an example of the mechanical pencil. It is a cross-sectional view which shows the cross section which follows the (III)-(III) line | wire in FIG. 1 about an example of the mechanical pencil. (A) is a principal part longitudinal cross-sectional view which shows the front-end side part of the axial cylinder 10, and (b) is a principal part expanded view which shows the part from an outer peripheral surface side about an example of the mechanical pencil. (A) is a longitudinal cross-sectional view which shows an example of a front-end | tip guide member about an example of the mechanical pencil, (b) is a principal part expanded view which shows the front-end | tip guide member from an outer peripheral surface side. (A) is a longitudinal cross-sectional view which shows a lead core holding mechanism about an example of the mechanical pencil, (b) is a principal part expanded view which shows the lead core holding mechanism from the outer peripheral surface side. About an example of the mechanical pencil, (1a) to (3a) are longitudinal sectional views showing an operation when a protruding lead core is pressed, and only a portion moved with respect to the previous state is hatched. (1b)-(3b) in the figure are the principal part expanded views which show the operation | movement. About an example of the mechanical pencil, (4a) to (6a) are longitudinal sectional views showing the operation following FIG. 7, and only the portion moved with respect to the previous state is hatched. (4b)-(6b) in the figure are the principal part expanded views which show the operation | movement. About an example of the mechanical pencil, (1a) to (3a) are longitudinal sectional views showing the operation when the tip guide member is pressed, and only the portion moved with respect to the previous state is hatched. (1b)-(3b) in the figure are the principal part expanded views which show the operation | movement. About an example of the mechanical pencil, (a) to (b) are longitudinal sectional views showing the operation when the rear end is knocked, and only the part moved with respect to the previous state is hatched. (C)-(d) is a longitudinal cross-sectional view which shows the operation | movement following FIG. 10 about an example of the mechanical pencil, and only the part which moved with respect to the previous state is hatched. It is a longitudinal cross-sectional view of the mechanical pencil which shows the other examples of the mechanical pencil concerning this invention. About other examples of the mechanical pencil, (1a) to (5a) are longitudinal sectional views showing the operation when the protruding lead core is pressed, and only the portion moved with respect to the previous state is hatched. (1b)-(5b) in the figure are the principal part expanded views which show the operation | movement. About other examples of the mechanical pencil, (a) to (d) are longitudinal sectional views showing the operation when the rear end is knocked, and only the portion moved with respect to the previous state is hatched.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present specification, “front” means the direction in which the mechanical pencil 1 extends the lead core p, and “rear” means the opposite direction.

  This mechanical pencil 1 is a mechanical pencil comprising a shaft cylinder 10, a lead core feeding mechanism A for feeding out a lead core by a retreat operation and a forward operation relative to the shaft cylinder 10, and an urging member. The lead lead feeding mechanism A is moved backward by the backward pressing force applied to the lead p, and the lead lead feeding mechanism A is moved forward by the biasing force of the biasing member when the pressing force is released, Lead lead p is fed forward from lead lead feeding mechanism A.

The lead lead feeding mechanism A includes a chuck mechanism 20 that clamps and releases the lead lead p in the shaft tube 10, and a tip guide member 40 that guides the lead lead p inserted from the chuck mechanism 20 to the front. And a lead core holding mechanism 50 provided to hold the lead core p with a force weaker than the clamping force of the chuck mechanism 20 and to move back and forth between the tip guide member 40 and the chuck mechanism 20. .
In addition, the biasing member biases the chuck mechanism 20 to the shaft cylinder 10 and biases it forward, and the lead core holding mechanism 50 to the chuck mechanism 20 and biases it forward. And a second urging member 32.
Further, in the lead core feeding mechanism A of the present embodiment, a knock member 60 provided so as to be able to advance and retract by a predetermined amount with respect to the shaft tube 10 with the operation portion 61 exposed from the rear end portion of the shaft tube 10, and the knock member 60 And a third urging member 33 that urges the lead member rearward, and the lead core p can be extended also by a knocking operation from the rear side with respect to the knock member 60.

The shaft cylinder 10 is formed in a long cylindrical shape covering substantially the entire length of the mechanical pencil 1, and has an engagement groove 11 that engages with the lead core holding mechanism 50 on the inner front end side thereof. The rear portion has a step portion 12 that engages with the chuck mechanism 20.
A spring receiving portion 13 that receives the first urging member 31 and the third urging member 33 is fixed to the rear side of the shaft tube 10, and a knocking end is further provided on the rear end side of the spring receiving portion 13. A step portion 14 is formed that restricts the rearward movement of the lead core insertion member 62 constituting the member 60.
According to the illustrated example, the shaft tube 10 has a structure in which a front shaft 10 a on the front side of the spring receiving portion 13 and a rear shaft 10 b on the rear side of the spring receiving portion 13 are connected via the spring receiving portion 13. However, it is possible to adopt an integrally cylindrical aspect, an aspect including three or more cylindrical members, and the like.
As another example, the spring receiving portion 13 is omitted, and the first urging member 31 and the third urging member 33 are replaced with the functions of the first urging member 31 and the third urging member 33. You may make it provide the urging member to have together. More specifically, the biasing member in this case is, for example, a coil that extends between the rear end of the rear sleeve 21b and the flange portion 62c1 of the lead core insertion member 62 and has a spring load set appropriately. A spring can be used.

The engagement groove 11 is a groove formed on the inner peripheral surface of the front end side of the shaft tube 10 and, as particularly shown in FIG. The first inclined portion 11b connected to the rear side of the first straight recess 11a and inclined rearwardly in the circumferential direction, and the first inclined portion 11b connected to the rear side of the first inclined portion 11b and linearly moved to the rear of the shaft cylinder. It is comprised from the 2 straight recessed part 11c.
In addition, although this engagement groove | channel 11 is formed in the concave groove shape according to the example of illustration, you may form in the hole shape which penetrates the axial cylinder 10 surrounding wall as another example.

  The step portion 12 is formed by expanding the inner peripheral surface of the shaft tube 10 stepwise toward the rear, and restricts forward movement of the chuck mechanism 20 described later.

The spring receiving portion 13 receives the rear end seat portion of the first biasing member 31 by the front side portion, and receives the front end seat portion of the third biasing member 33 by the rear side portion.
A lead core insertion member 62, which will be described later, is inserted through the axial center side portion of the spring receiving portion 13 so as to be able to advance and retract.

  The step portion 14 is formed so as to reduce the diameter of the inner peripheral surface of the shaft tube 10 in a stepwise manner toward the rear, and restricts rearward movement of a lead core insertion member 62 described later.

Further, the chuck mechanism 20 moves forward and backward by a predetermined amount in the shaft cylinder 10, holds the lead core p so that it cannot move backward and can move forward when moving forward, and releases the lead core when retracted to a predetermined release position. It is a mechanism to do.
The chuck mechanism 20 releases the lead lead holding in the lead lead feeding direction, holds the lead lead p with a holding force capable of withstanding the writing pressure in the lead lead immersion direction, and holds the lead lead p against the held lead lead p. When a force greater than the writing pressure is applied from the front side, the holding force is released.

More specifically, the chuck mechanism 20 has a substantially cylindrical sleeve 21 that is movable forward and backward in the shaft cylinder 10 and is urged forward by the first urging member 31; The chuck portion 22 that is urged rearward by the second urging member 32 and fits and contracts from the front side of the sleeve 21 to sandwich the lead core, and the chuck portion 22 is smoothly engaged with and disengaged from the sleeve 21. And a ball 23 to be moved.
When the chuck mechanism 20 is retracted by a predetermined amount, the rear end of the chuck portion 22 is fixed to the abutment portion 62b1 (a portion provided on the front end side of a knock member 60 described later) that is stationary relative to the chuck portion 22. The chuck portion 22 is released by being brought into contact with.

  The sleeve 21 has a front sleeve 21a that is loosely fitted to a front portion of the inner peripheral surface of the shaft tube 10 so as to be able to advance and retreat, and a rear portion of the inner peripheral surface of the coaxial tube 10 that is closer to the rear portion. The rear sleeve 21b is loosely fitted so as to be able to advance and retreat.

  The front sleeve 21a has a substantially stepped cylindrical shape in which the outer peripheral surface of the front end side and the outer peripheral surface of the rear end side are reduced in diameter, the outer peripheral surface on the front end side thereof is reduced in diameter, and the diameter is increased at the front end portion of the reduced diameter portion. It has the latching protrusion 21a1 which protrudes in a direction.

A plurality (two in the illustrated example) of the latching protrusions 21a1 are provided at equal intervals in the circumferential direction.
This latching protrusion 21a1 engages with a tip guide member 40 described later, and pulls the tip guide member 40 backward when it moves rearward.

In addition, an inclined surface 21a2 that gradually decreases in diameter toward the rear is formed on the front end side of the inner peripheral surface of the front sleeve 21a. The inclined surface 21a2 is a chuck portion 22 that is fitted through the ball 23 from the front. Is gradually reduced in diameter.
Further, a protrusion 21a3 protruding in the shaft tube centripetal direction is provided on the rear side of the inclined surface 21a2 of the inner peripheral surface of the front sleeve 21a. This protrusion 21a3 engages with a locking protrusion 22b1 on the outer surface of the rear end side of the chuck portion 22 described later, thereby preventing the chuck portion 22 from being pulled out forward from the front sleeve 21a.

In addition, the rear side of the outer peripheral surface of the front sleeve 21a is a reduced diameter portion 21a5 whose rear side is smaller than the front side with the stepped portion 21a4 as a boundary.
The step portion 21a4 functions as a contact surface that is contacted by the front end of the rear sleeve 21b when the rear sleeve 21b moves forward.
The reduced diameter portion 21a5 is formed to have an outer diameter having a gap with the inner peripheral surface of the rear sleeve 21b so that the diameter can be slightly elastically increased in the rear sleeve 21b.
On the rear end side of the inner peripheral surface of the reduced diameter portion 21a5, a convex portion 21a6 is formed so as to fit into a concave portion on the front end side of the outer peripheral surface of the lead core insertion member 62 described later.

The rear sleeve 21b has a cylindrical shape with substantially the same diameter over the entire length, and abuts the front end portion against the stepped portion 12 in the shaft tube 10 when the rear sleeve 21b moves forward.
The rearward movement of the rear sleeve 21 b is regulated by contacting the spring receiving portion 13.

The chuck portion 22 is made of a synthetic resin material or metal material having elasticity, and a plurality of (for example, 2 or 3) claw portions 22a arranged concentrically so as to be located around the lead core p; It consists of the cylinder part 22b which connects this nail | claw part 22a by the rear end side.
The chuck portion 22 holds the lead core p when the diameter of the claw portion 22a is reduced, and releases the lead core p when the diameter of the claw portion 22a is increased.

  The nail | claw part 22a is connected to the cylinder part 22b front end side so that it may expand in diameter by elastic force. A concave portion 22a1 for loosely fitting a substantially spherical ball 23 is provided on the surface of the claw portion 22a on the axial tube centrifugal direction side (see FIG. 7 (1a)).

The cylindrical portion 22b has a locking protrusion 22b1 that is locked to the protrusion 21a3 on the inner peripheral surface of the front sleeve 21a on the rear end side of the outer peripheral surface thereof.
The inner peripheral surface of the cylindrical portion 22b is formed to have an inner diameter having a gap with the outer peripheral surface of the lead core p. A front end portion of a lead core insertion member 62, which will be described later, is fitted in this gap.

The chuck portion 22 configured as described above is retracted relative to the front sleeve 21a and is fitted to the inclined surface 21a2 on the inner peripheral surface of the front end of the front sleeve 21a, thereby closing the plurality of claws 22a and sandwiching the lead core p. To do.
In this clamping state, when the lead core p is pressed backward, the clamping force by the claw portion 22a is further increased, so that the pressed lead core p is prevented from moving backward.
In this clamping state, when the lead core p is pulled forward, the plurality of claw portions 22a are smoothly detached from the front sleeve 21a by the action of the ball 23, so that the advancement of the lead core p is not hindered.

Moreover, according to the example of illustration, each of the 1st biasing member 31, the 2nd biasing member 32, and the 3rd biasing member 33 is a coil spring.
The first urging member 31 has a rear end seat portion received by the spring receiving portion 13 and urges the rear sleeve 21b forward by bringing the front end seat portion into contact with the rear end of the rear sleeve 21b. ing.
The urging force of the first urging member 31 is appropriately set so that the first urging member 31 does not contract due to the writing pressure applied in a normal writing state.

The second biasing member 32 presses the lead core holding mechanism 50 forward and biases the chuck portion 22 backward. In other words, the second urging member 32 urges the lead core holding mechanism 50 and the chuck portion 22 of the chuck mechanism 20 in the separating direction.
The urging force of the second urging member 32 is appropriately set so as to be weaker than the urging force of the first urging member 31.

  The third urging member 33 has its front end seat portion received by the spring receiving portion 13, and its rear end seat portion is brought into contact with the flange portion 62 c 1 of the lead core insertion member 62 to move the lead core insertion member 62 rearward. Energized.

The tip guide member 40 is inserted through the lead core p fed from the chuck mechanism 20 and guided forward, and can move forward and backward by a predetermined amount relative to the shaft tube 10, and is retracted by being pulled by the chuck mechanism 20. It is provided to do.
More specifically, the tip guide member 40 is integrally formed from a projecting tube portion 41 projecting forward from the front end of the shaft tube 10 and a tube portion 42 connected to the rear end of the projecting tube portion 41. The

  The protruding tube portion 41 is exposed to protrude forward from the front end of the shaft tube 10 and is tubular so that the lead core p is inserted through the axial center side (in accordance with the illustrated example, the diameter is reduced stepwise toward the front). Stepped tube).

  The cylindrical portion 42 is formed in a substantially cylindrical shape in which a lead core holding mechanism 50 described later is fitted so as to be able to advance and retract and rotate. As shown in FIG. 5, the cylindrical portion 42 includes a first convex portion 42a, a second inclined portion 42b1, and a plurality of engaging hole portions 42c (see FIG. 5).

  The first convex portion 42a is formed in a substantially columnar shape protruding in the centrifugal direction from the outer peripheral surface of the front end side of the cylindrical portion 42, and is loosely fitted into the engaging groove 11 on the inner peripheral surface of the shaft cylinder 10.

The second inclined portion 42b1 is an inclined surface inclined symmetrically with respect to the first inclined portion 11b of the engaging groove 11 on the inner peripheral surface of the shaft cylinder 10.
According to the illustrated example, the second inclined portion 42b1 is formed as a portion on the front end side of the inner surface of the engagement hole 42b by providing an engagement hole 42b having a triangular shape in plan view in the cylindrical portion 42 of the tip guide member 40. The

A plurality of engagement holes 42c are provided so that the latching protrusions 21a1 of the sleeve 21 are loosely fitted.
Each engaging hole portion 42c is formed so that the underlying latching protrusion 21a1 can move in the front-rear direction. According to the illustrated example, the length in the front-rear direction (vertical direction in the figure) is longer than the latching protrusion 21a1. It is formed in a rectangular shape.
The engagement hole portion 42c is a through hole in the illustrated example, but can be a bottomed concave portion.

The lead core holding mechanism 50 is provided in front of the chuck mechanism 20 and is configured to be movable back and forth and to hold the lead core p with a predetermined holding force.
More specifically, the lead core holding mechanism 50 includes a slide portion 51 that is movably engaged with the tip guide member 40, and an elastic pressure contact with the outer peripheral surface of the lead core within the slide portion 51. The elastic pressure contact portion 52 is formed. (See Figure 6)

  The slide part 51 is formed in a substantially cylindrical shape that fits into the cylinder part 42 of the tip guide member 40. On the outer peripheral surface of the slide portion 51, there are a second convex portion 51a that engages with the second inclined portion 42b1 of the tip guide member 40, and an abutting portion 51b that abuts on the front sleeve 21a when it moves forward. Provided.

  The second convex portion 51a is a substantially columnar protrusion that protrudes in the centrifugal direction from the outer peripheral surface of the slide portion 51, and is loosely fitted in the engagement hole 42b of the distal end guide member 40, and the second protrusion 51a in the engagement hole 42b. While being in sliding contact with the inclined portion 42b1, it engages with the engaging groove 11 on the inner surface of the shaft tube 10 on the protruding end side.

The contact part 51b is a protrusion protruding in the centrifugal direction from the outer peripheral surface of the rear end of the slide part 51. According to the illustrated example, the contact part 51b is provided in an annular shape over substantially the entire periphery of the slide part 51.
When the front sleeve 21a moves forward, the contact portion 51b receives the latching protrusion 21a1 at the front end of the front sleeve 21a from the front side (see FIG. 7 (3a)).

  Further, the lead core insertion hole 51c through which the lead core p is inserted and the elastic pressure contact portion 52 cannot be advanced and retracted on the inner peripheral surface of the slide portion 51 in order from the front end side so as to approach or contact the outer peripheral surface of the lead core p. A fitting hole 51d to be fitted to the first biasing member 32 and a spring receiving portion 51e that receives the front end side of the second urging member 32 are arranged in a substantially stepped cross section that gradually increases in diameter toward the rear.

The elastic pressure contact portion 52 is formed of an elastic body such as rubber or elastomer resin. The rear side of the outer peripheral surface of the elastic pressure contact portion 52 is fitted into the slide portion 51, and the front side is gradually reduced in diameter toward the front.
The rear side of the inner surface of the elastic pressure contact portion 52 is gradually reduced in diameter toward the front, and the front side is formed in a substantially inner cylindrical shape that is elastically pressed against the outer peripheral surface of the lead core p.
According to the elastic pressure contact portion 52, the lead core p to be inserted is held with a predetermined holding force.
In addition, the elastic pressure contact part 52 of the example of illustration may be called a core breaker by those skilled in the art.
Further, the elastic pressure contact portion 52 can be integrally formed with the slide portion 51 in the manner of insert molding or the like.

  The knock member 60 includes a pressing operation portion 61 that is exposed by protruding rearward from the rear end of the shaft tube 10, and a lead that is connected to the front side of the pressing operation portion 61 and moves forward and backward integrally with the pressing operation portion 61. It is comprised from the core insertion member 62 (refer FIG. 1).

  The pressing operation unit 61 is a cap-shaped member that is detachably fitted to the rear end of the lead core insertion member 62.

  The lead core insertion member 62 includes an insertion portion 62a inserted into the rear end side inside the chuck portion 22, an engagement cylinder portion 62b engaged with the inner peripheral surface of the front sleeve 21a on the rear side of the insertion portion 62a, A lead tank part 62c capable of containing a plurality of lead cores p is provided on the rear side of the engaging cylinder part 62b.

  The insertion portion 62a is formed in a substantially cylindrical shape that can be loosely inserted between the inner peripheral surface of the cylindrical portion 22b of the chuck portion 22 and the outer peripheral surface of the lead core p.

The engagement cylinder part 62b has a substantially larger diameter than the insertion part 62a and is substantially cylindrical so that it can be loosely inserted between the inner peripheral surface of the reduced diameter part 21a5 of the front sleeve 21a and the outer peripheral surface of the lead core p. It is formed.
The step portion serving as the boundary between the engagement cylinder portion 62b and the insertion portion 62a functions as an abutment portion 62b1 that abuts against the chuck portion 22 when it is retracted by a predetermined amount to loosen the clamping state of the chuck portion 22 (FIG. 7). reference).

An engagement recess 62b2 (see FIG. 7) that engages with the protrusion 21a6 on the rear end side of the front sleeve 21a is formed on the outer peripheral surface of the engagement cylinder portion 62b in the middle in the length direction.
The engagement recess 62b2 is formed to have a length that allows a predetermined amount of movement of the underlying protrusion 21a6 in the front-rear direction. The rear end portion of the engaging recess 62b2 is inclined so as to ride up rearward while elastically expanding the protrusion 21a6 (see FIG. 11C).

The lead tank part 62c has a larger diameter than the engaging cylinder part 62b, and is formed in a substantially cylindrical shape in which a plurality of lead cores p can be contained.
A flange portion 62c1 for receiving the rear end portion of the third urging member 33 projects in an annular shape on the rear end side outer peripheral surface of the core tank portion 62c.
A first urging member 31 is mounted around a portion of the core tank portion 62c on the front side of the spring receiving portion 13, and a third urging member 33 is attached to a portion on the rear side of the spring receiving portion 13. Disguise.
The core tank portion 62c is inserted into the spring receiving portion 13 to be in sliding contact with the inner peripheral surface of the spring receiving portion 13, and the outer peripheral surface of the flange portion 62c1 is in sliding contact with the inner peripheral surface of the shaft tube 10. Then, it is guided in the front-rear direction.
In addition, although illustration is abbreviate | omitted, you may make it attach an eraser to the rear end of the lead core insertion member 62 (specifically core tank part 62c) as needed.

Next, the characteristic effect of the mechanical pencil 1 having the above-described configuration will be described.
First, description will be given of an operation for adjusting the protruding amount of the lead core p when the amount of the lead core p protruding from the front end of the tip guide member 40 is too long. In FIGS. 7 and 8 (1a) to (6a), the hatched portion indicates the portion that has moved relative to the previous state, and the portion that has not moved relative to the previous state is hatched. Is omitted.

  7 (1a) and (1b) show a stationary state in which the lead pencil p protrudes longer than usual from the front end of the tip guide member 40 before the mechanical pencil 1 is operated.

First, when the lead core p is pressed against the writing surface q with a force equal to or higher than the writing pressure in a normal writing state, the lead core p is sandwiched between the chuck portion 22 and the chuck portion 22 and the ball 23. The first urging member 31 is attached to the front sleeve 21a that holds the chuck portion 22 in a sandwiched state and the rear sleeve 21b that is in contact with the rear end of the front sleeve 21a. Retreat in unison against the forces.
At the time of the retreat, the rear sleeve 21b retreats relative to the knock member 60. Therefore, the engagement state between the convex portion 21a6 on the rear end side of the rear sleeve 21b and the engagement concave portion 62b2 on the front end side of the knock member 60. Comes off.

  Further, since the latching protrusion 21a1 on the front end side of the front sleeve 21a is latched by the engaging hole portion 42c of the tip guide member 40 during the retreat, the tip guide member 40 and the lead core are interlocked with the retreat. The holding mechanism 50 is also retracted by the dimension x1 shown in FIG.

  When the tip guide member 40 is retracted as described above, as shown in FIG. 7B, the first convex portion 42a of the tip guide member 40 contacts the first inclined portion 11b of the inner peripheral surface of the shaft tube 10. .

Next, the engagement relationship among the shaft cylinder 10, the lead core holding mechanism 50 and the tip guide member 40 is retracted to retract the lead core holding mechanism 50 relative to the tip guide member 40 in conjunction with the retract of the tip guide member 40. that acts as an interlocking means.
More specifically, when the pressing force against the lead core p is maintained and the backward movement of the distal end guide member 40 is continued, the distal end guide member 40 is moved by the sliding contact between the first convex portion 42a and the first inclined portion 11b. 7 (2b) is retracted by the dimension x2 while rotating from the state shown in FIG. 7 (2b) to the state shown in FIG.
Further, as the tip guide member 40 is rotated and retracted, the second convex portion 51a of the lead core holding mechanism 50 is slidably contacted with the second inclined portion 42b1 of the tip guide member 40. In other words, the slide portion 51 and the elastic pressure contact portion 52) are retracted by the dimension s1 (see FIG. 7 (3a)) relative to the tip guide member 40.

  The contact portion 51b of the lead core holding mechanism 50 contacts the latching protrusion 21a1 on the front end side of the front sleeve 21a by the retreat (see FIGS. 7 (3a) and (3b)), and retreats with the lead core p substantially simultaneously. The rear end of the chuck portion 22 contacts the contact portion 62b1 at the front end of the lead core insertion member 62 (see FIG. 7 (3a)).

Therefore, if the pressing against the lead core p is continued, the chuck portion 22 is abutted against the abutting portion 62b1 and does not retreat, so that the chuck portion 22 has moved forward relative to the front sleeve 21a, and the release force that loosened the clamping force against the lead core p is released. It becomes a state.
Therefore, only the lead core p is retracted, and the front end of the lead core p is flush with the front end of the tip guide member 40 as shown in FIG. 8 (4a).

  Since the lead core p and the elastic pressure contact portion 52 are in an elastic pressure contact state when only the lead core p is retracted, the lead core p can slide back on the inner surface of the elastic pressure contact portion 52. is there. That is, the retraction of the lead core p is not blocked by the elastic pressure contact portion 52.

And if the press with respect to the lead core p continues further, the pressing force will be added to the front end of the lead core p and the front-end | tip guide member 40 (refer FIG. 8 (4a)).
Therefore, the pressing force to the rear of the tip guide member 40 is transmitted to the lead core holding mechanism 50, and further the pressing force is transmitted to the rear of the lead core holding mechanism 50 to the front sleeve 21a and the rear sleeve 21b.
Therefore, the lead core p, the tip guide member 40, the lead core holding mechanism 50, the front sleeve 21a, and the rear sleeve 21b are integrally retracted, and the gap s2 between the rear sleeve 21b and the spring receiving portion 13 is narrowed. The rear sleeve 21b comes into contact with the spring receiving portion 13 (see FIG. 8 (5a)). The amount of retreat at this time is the dimension x3 in the figure.

Next, when the pressing force against the lead core p is released, the urging force of the first urging member 31 causes the rear sleeve 21b and the front sleeve 21a to start moving forward.
At substantially the same time, the urging force of the second urging member 32 opposes the chuck portion 22 and the lead core holding mechanism 50 starts moving forward while holding the lead wick p.
Then, the lead core holding mechanism 50 moving forward at this time causes the second convex portion 51a to slide in contact with the second inclined portion 42b1 of the tip guide member 40 (see FIG. 8 (5b)).
Therefore, the distal end guide member 40 moves forward while rotating in the direction of rotation opposite to that at the time of reverse movement (rightward in the developed views of FIGS. 8 (5b) and 6b).

Accordingly, during the advancement, the lead core holding mechanism 50 holding the lead core p approaches the tip guide member 40 and the lead core p is projected from the front end of the tip guide member 40.
During this advancement, the lead core p is pulled forward by the lead core holding mechanism 50, so that the chuck portion 22 is slightly advanced and loosened relative to the front sleeve 21a. It is not obstructed by the clamping force.

In FIG. 8, the dimension x4 indicates the amount by which the tip guide member 40 advances after the pressing force against the lead core p is released as described above, and the dimension x5 indicates the amount by which the lead core p advances (that is, the tip guide). The amount protruding from the front end of the member 40 is shown.
The advance amount x5 (protrusion amount) of the lead core p is a clearance s1 (see FIG. 5) formed between the tip guide member 40 and the lead core holding mechanism 50 when the tip guide member 40 and the lead core holding mechanism 50 are retracted. 8 (see 5a)).

The operation shown in FIGS. 7 and 8 has been described as an operation for setting the lead core p protruding too much in an appropriate amount, but according to the present embodiment, the amount of protrusion is too small (the tip guide member). The lead core p (including the case where the front end of the lead 40 and the front end of the lead core p are flush with each other) can be made to protrude by an appropriate amount by the same operation as described above.
That is, the front end of the lead core p (see FIG. 9 (1a)) that is flush with the front end (not shown) of the lead core p with a small amount of protrusion is applied to the writing surface q with a force that is greater than the writing pressure. The lead core p and the tip guide member 40 are retracted (FIG. 9 (2a)), and then the pressing force is released (FIG. 9 (3a)).
Also in this case, in substantially the same manner as the operations shown in FIGS. 7 to 8 described above, the lead core holding mechanism 50 slides [or moves] as the lead core p and the tip guide member 40 are retreated by the dimension x1 ′ (see FIG. 7). 9 (2a)), when the pressing force to the lead core p is subsequently removed, the tip guide member 40 moves forward by the dimension x2 ′, and the lead core p moves relative to the tip guide member 40 together with the lead core holding mechanism 50. As a result, the protrusion amount x3 ′ of the lead core p becomes an appropriate amount (see FIG. 9 (3a)). The protruding amount x3 ′ is substantially the same as the interval s1 when the tip guide member 40 and the lead core holding mechanism 50 are retracted.

In the above, the operation of causing the lead core p to protrude from the tip guide member 40 by the operation of pressing the lead core p from the front has been described. However, according to the mechanical pencil 1 of the present embodiment, the operation of knocking the knock member 60 is also performed. The lead core p can be protruded. Hereinafter, the operation in that case will be described with reference to FIGS.
In FIGS. 10 and 11 (a) to 11 (d), hatched portions indicate portions that have moved relative to the previous state, and portions that have not moved relative to the previous state are hatched. Is omitted.

FIG. 10A shows a stationary state in which the lead pencil p does not protrude from the front end of the distal end guide member 40 before the mechanical pencil 1 is operated.
At this time, a gap s3 is formed between the front end of the front sleeve 21a and the rear end of the lead core holding mechanism 50. At the same time, a gap s4 is formed between the rear end of the chuck portion 22 and the contact portion 62b1 of the lead core insertion member 62.

  As shown in FIG. 10B, when the knock member 60 moves forward by the knocking operation, the engaging recess 62b2 on the front end side of the knock member 60 that moves forward is hooked on the convex portion 21a6 on the rear end side of the front sleeve 21a. Therefore, as the knock member 60 advances, the front sleeve 21a also advances.

  During this advancement, the chuck portion 22 is also pushed forward by the front sleeve 21a, and the chuck portion 22 is fitted to the front sleeve 21a. The lead core p moves forward, and a proper amount projects from the front end of the tip guide member 40.

Further, the advanced front sleeve 21a abuts on the rear end of the lead core holding mechanism 50 as shown in FIG.
More specifically, when the front sleeve 21a moves forward, the latching protrusion 21a1 at the front end of the front sleeve 21a moves forward in the engagement hole portion 42c (see FIG. 5) of the tip guide member 40, and leads It contacts the contact portion 51b at the rear end of the core holding mechanism 50.

Furthermore, when the knock member 60 continues to advance, the front sleeve 21a elastically expands so that the convex portion 21a6 of the front sleeve 21a rises to the rear of the engaging concave portion 62b2 of the lead core insertion member 62. Thus, the engagement between the convex portion 21a6 and the engaging concave portion 62b2 is released. Therefore, the lead core insertion member 62 moves forward relative to the front sleeve 21a so as to narrow the gap s4 between the lead core insertion member 62 and the chuck portion 22.
Then, the contact portion 62b1 on the front side of the lead core insertion member 62 contacts the rear end portion of the chuck portion 22 (FIG. 11C).

Further, when the knock member 60 continues to advance, the advancing knock member 60 pushes the chuck portion 22 and moves forward so that the chuck portion 22 is disengaged from the front sleeve 21a (FIG. 11D). reference).
Therefore, the chuck portion 22 is in a released state where the lead core p is not sandwiched.

When the pressing force on the knock member 60 is released in the released state, the knock member 60 moves rearward by the urging force of the third urging member 33. At the same time, the chuck portion 22 and the lead core holding mechanism 50 are separated by the second urging member 32.
By this rearward movement, the engagement concave portion 62b2 on the front end side of the knock member 60 returns to the state of being hooked on the convex portion 21a6, and the front sleeve 21a also moves backward following the further backward movement of the knock member 60 (not shown). ).
At the time of this retraction, the lead core p is released from the clamping force of the chuck portion 22 and is held by the lead core holding mechanism 50, so that it does not move backward and protrudes from the front end of the tip guide member 40 by an appropriate amount. Maintained.

The mechanical pencil 1 according to the above embodiment is configured such that the chuck portion 22 is fitted to and detached from the front sleeve 21a via the ball 23. However, as another example, the mechanical pencil 2 shown in FIG. Good.
Note that the mechanical pencil 2 is a part of the mechanical pencil 1 whose structure is partially changed, and therefore, the same reference numerals are assigned to portions that operate substantially the same as the mechanical pencil 1, and the detailed description thereof is omitted. .

  The mechanical pencil 2 omits the ball 23 from the mechanical pencil 1 and replaces the chuck portion 22 with the chuck portion 22 ′, the front sleeve 21a with the sleeve 21a ′, and the lead core insertion member 62 with the lead core insertion member 62 ′. The configuration is

The chuck portion 22 ′ is a cylinder that connects a plurality (for example, 2 or 3) of claw portions 22 a ′ arranged concentrically so as to be positioned around the lead core p, and the claw portion 22 a ′ on the rear end side. Part 22b.
The claw portion 22a ′ of the chuck portion 22 ′ has a shape in which the concave portion 22a1 is omitted from the chuck portion 22 of the first embodiment, and an inclined portion that is reduced in diameter toward the rear is formed on the rear side of the outer periphery. doing.

Further, the sleeve 21a ′ has a configuration in which the reduced diameter portion 21a5 on the rear side is omitted from the front sleeve 21a.
On the front end side of the inner peripheral surface of the sleeve 21a ', an inclined surface that gradually decreases in diameter toward the rear is formed, and this inclined surface gradually reduces the diameter of the chuck portion 22' that is fitted from the front. .

  The lead core insertion member 62 ′ includes an insertion portion 62a that is inserted into the rear end side inside the chuck portion 22 ′, and a core tank portion 62c that can contain a plurality of lead cores p behind the insertion portion 62a. And a step portion between the insertion portion 62a and the core tank portion 62c serves as a contact portion 62b1 ′ for contacting the rear end of the chuck portion 22 ′.

When the lead lead p is knocked from the front, the mechanical pencil 2 operates in substantially the same manner as the mechanical pencil 1 having the above-described configuration, and the lead lead p when it is too long or too short is used as the tip guide member 40. It can be made to be in a state where it protrudes from the front end by an appropriate amount (see FIGS. 13 (1a) (1b) to (5a) (5b)).
During the above operation, the mechanical pencil 2 does not have the convex portion 21a6 on the rear end side of the rear sleeve 21b and the engaging concave portion 62b2 on the front end side of the knock member 60 in the case of the mechanical pencil 1, Does not occur (see FIGS. 7 (1a) and (2a)).

Further, in this mechanical pencil 2, when the knock member 60 is knocked from behind, the lead pencil p protrudes from the front end of the tip guide member 40 by an appropriate amount by operating in substantially the same manner as the mechanical pencil 1 configured as described above. (See FIGS. 14A to 14D).
During the above operation, the mechanical pencil 2 does not have the convex portion 21a6 on the rear end side of the rear sleeve 21b and the engaging concave portion 62b2 on the front end side of the knock member 60 in the case of the mechanical pencil 1, Does not occur (see FIGS. 10B and 10C).

That is, in the case of the mechanical pencil 2, when the abutting portion 62c1 'of the knock member 60 abuts on the rear end of the chuck portion 22' (see FIG. 14B) and further advances, the chuck portion 22 ' The sleeve 21a 'fitted around the periphery of the sleeve moves forward (see FIG. 14C).
Then, the advanced sleeve 21a ′ contacts the lead core holding mechanism 50, and the chuck portion 22 ′ is released (see FIG. 14D).
Therefore, in the mechanical pencil 2, the convex part 21a6 and the engagement concave part 62b2 in the mechanical pencil 1 are unnecessary.

However, if the former mechanical pencil 1 does not have the convex portion 21 a 6 and the engaging concave portion 62 b 2, the front sleeve 21 a is engaged with the ball 23 so that it can be easily detached around the chuck portion 22. Therefore, even if the knock member 60 abuts on the rear end of the chuck portion 22 and further moves forward, only the chuck portion 22 and the ball 23 move forward independently of the front sleeve 21a. Cannot be moved forward with the lead core sandwiched.
Therefore, in the case of the mechanical pencil 1, the front sleeve 21a is interlocked with the advancement of the knock member 60 by the fitting of the convex portion 21a6 and the engaging concave portion 62b2, and the front sleeve 21a is in contact with the lead core holding mechanism 50. The lead core is held between the chuck portions 22 (FIGS. 10A and 10B).

10: Shaft cylinder 11: Engaging groove 11b: First inclined portion 20: Chuck mechanism 21: Sleeve 22: Chuck portion 31: First urging member 32: Second urging member 33: Third urging member 40: Tip Guide member 42a: 1st convex part 42b: Engagement hole 42b1: 2nd inclination part 50: Lead core holding mechanism 51: Slide part 51a: 2nd convex part 52: Elastic pressure contact part 60: Knock member 61: Press operation part 62b1 : Abutting part A: Lead lead feeding mechanism p: Lead lead

Claims (5)

A shaft cylinder, a chuck mechanism for pinching and releasing the lead core in the shaft cylinder, a tip guide member for inserting the lead core fed from the chuck mechanism and guiding it forward, and a lead core for the chuck mechanism It has a lead core holding mechanism that can be held with a force weaker than the clamping force and can be moved back and forth between the tip guide member and the chuck mechanism, and an urging member. A mechanical pencil comprising a lead lead feeding mechanism for feeding a lead lead,
The chuck mechanism releases the chuck portion forward from the sleeve in the lead lead feeding direction to release the lead lead holding by the chuck portion, and fits into the sleeve from the front side in the lead lead insertion direction to reduce the diameter. When the lead core is held with a holding force that can withstand the writing pressure by the chuck portion and a force greater than the writing pressure is applied from the front side to the held lead core, It is configured to release the holding force due to the fitting between the sleeve and the chuck portion by bringing the end into contact with the non-moving contact portion relative to the chuck portion,
The urging member includes a first urging member that urges the sleeve forward against the shaft cylinder, and a second urging member that urges the chuck portion and the lead core holding mechanism in the separating direction. Comprising
When the lead lead feeding mechanism is applied with a rearward pressing force greater than the pen pressure on the lead lead, the chuck portion is moved backward to come into contact with and release the contact portion. When the is released, the sleeve is moved away from the contact portion by the urging force of the first urging member and fitted to the chuck portion to advance the chuck portion and the lead core. Characteristic mechanical pencil.   When a rearward pressing force greater than the pen pressure is applied to the lead core protruding forward from the tip guide member, the chuck portion holding the lead core moves backward by this pressing force. The mechanical pencil according to claim 1, wherein the mechanical pencil comes into contact with the contact portion. The tip guide member is provided so as to be able to advance and retract by a predetermined amount relative to the shaft tube and to be retracted by being pulled by the chuck portion;
In conjunction with the retreat of the tip guide member, the lead core holding mechanism is provided with a retreat interlocking means for retreating relative to the tip guide member,
Said retraction interlocking means includes a first inclined portion inclined a first protrusion provided on one of said the barrel front guide member, provided on the other of the rear oblique circumferential direction, the distal end together comprising a second protrusion provided on one guide member and one of said lead core holding mechanism, and a second inclined portion which is provided on the other of the inclined rearwards obliquely opposite circumferential direction, the lead core Engage the holding mechanism with respect to the shaft cylinder so that it can advance and retreat, and cannot rotate,
By the engagement of the first protrusion and the first inclined portion, the front guide member when retracted relative to the barrel is rotated in association with the retraction, the second convex portion and the second inclined portion engagement by claim 1 or 2 pencil according to the lead core holding mechanism is characterized in that so as to retract relative to the distal guide member of. The lead core holding mechanism, characterized in that it consists of said tip and slide portion movably engages the guide member, the elastic contact portion which is elastically pressed against the outer peripheral surface of the lead core in the sliding portion The mechanical pencil according to any one of claims 1 to 3. A knock member provided so as to be able to advance and retract by a predetermined amount with respect to the shaft cylinder in a state in which the operation portion is exposed from the rear end portion of the shaft cylinder or the outer peripheral portion of the shaft cylinder, and a third urging member for urging the knock member rearward wherein said abutting portion is formed at the front end of the knocking member, the knocking member the tip lead core from the guide member is characterized in that so as to be fed in any one of claims 1 to 4 by reciprocating the The mechanical pencil according to item 1.

Images