JP5476235B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil in which a lead core is rotated by writing pressure.

  When writing with a mechanical pencil, the front end of the lead core is unevenly reduced as the writing progresses, and there is a problem that the thickness and darkness of the drawn line are not constant. For this reason, the writer performs an operation of occasionally holding and rotating the shaft cylinder, but the operation is troublesome and the writing efficiency is reduced at present. Thus, for example, in the mechanical pencil described in Patent Document 1, the rotor in the shaft cylinder is rotated by the axial component of the writing pressure applied to the lead core during writing, and is held by the chuck unit in the rotor. The lead core is rotated.

However, according to the prior art shown in Patent Document 1, in order to rotate the lead core, the lead core and the rotor must be finely moved in the axial direction by writing pressure. You will feel the backlash in the axial direction on the core.
More specifically, when the writer holds the shaft cylinder and brings the lead core into contact with the writing surface, the shaft cylinder moves slightly forward relative to the lead core in contact with the writing surface. Will do. Further, when the lead core is separated from the writing surface, the lead core is separated from the writing surface after the shaft cylinder has moved slightly backward while the lead core is in contact with the writing surface. Therefore, the writer feels shakiness in the axial direction, and this shakiness in the axial direction has been a factor of lowering the writing feel.

International Publication No. 2007/142135 Pamphlet

  This invention makes it an example of a subject to cope with such a problem. That is, in the mechanical pencil in which the lead core is rotated by the writing pressure, it is an object of the present invention to prevent the lead core from rattling in the axial direction and to improve the writing feel.

  In order to achieve such an object, the technical means according to the present invention includes at least the following configuration.

  Sharp equipped with a shaft cylinder and a lead core feeding pipe having a tip protruding from the shaft cylinder, the lead core in the lead core feeding pipe being unrotatably held by a chuck and fed out from the tip In the pencil, the lead core feed pipe is supported by the shaft cylinder so that the tip side thereof swings in a direction intersecting the lead core direction, and the swing of the lead core feed pipe is centered on the lead core. The movement is converted into a movement in the rotational direction, and the chuck is rotated in one direction by the rotational movement.

By having such characteristics, the present invention has the following effects.
In a normal writing posture in which the shaft cylinder is inclined with respect to the writing surface, when the lead core is pressed against the writing surface, the leading end side of the lead core feeding tube holding the lead core swings in a direction intersecting the lead core direction. Then, the swing is converted into a motion in the rotational direction, and the chuck holding the lead core is rotated in one direction by the rotational motion.
Therefore, the lead core can be rotated without rattling in the axial direction, and thus the writing feel can be improved.

It is principal part sectional drawing which shows an example of the mechanical pencil which concerns on this invention. It is a use state figure of the mechanical pencil, (a) shows the state before the tip of the lead lead contacts the writing surface, (b) shows the state where the tip of the lead lead contacts the writing surface. Show. (I)-(I) sectional view and (II)-(II) sectional view in FIG. 1, (a) -I and (a) -II are the initial positions of the lead core feed pipe on the axial center side (B) -I and (b) -II show the state in which the lead core feed pipe is swung and rotated in the axial centrifugal direction, and (c) -I and (c)- II shows a state in which the lead core feed pipe is rotated and rotated in the shaft tube centripetal direction. FIG. 4 is an enlarged view of the main part of FIG. 3, (a) -I and (a) -II show the state where the lead core feed pipe is located at the initial position on the axial center side, and (b) -I and (b ) -II shows a state in which the lead core feeding pipe is swung and rotated in the axial centrifugal direction.

  In a preferred embodiment according to the present invention, a shaft cylinder and a lead core feeding pipe having a tip projecting from the shaft cylinder are provided, and the lead core in the lead core feeding pipe is non-rotatably held by a chuck and the tip In the mechanical pencil extended from the section, the lead core supply pipe is supported by the shaft cylinder so that the tip side thereof swings in a direction intersecting the lead core direction, and the swing of the lead core supply pipe is performed. Was converted into a movement in the rotational direction around the lead core, and the chuck was rotated in one direction by the rotational movement.

  In a more preferred form, the rear side of the lead core feed pipe swings in the opposite direction as the front side swings in a direction intersecting the lead core direction with respect to the support part for the shaft tube. A first rotating cam portion rotatably provided on the outer periphery on the rear side of the supporting portion in the lead core feed pipe, and a non-rotatable first fixed on the inner periphery of the shaft tube A cam portion is provided, and the first rotating cam portion is slidably contacted with the first fixed cam portion when swinging in the axial tube centrifugal direction together with the lead core feeding pipe, and the first rotating cam portion is The chuck is rotated by rotating in the one direction and rotating the first rotating cam portion.

  In a further preferred form, the first rotating cam portion has a plurality of sliding contact projections arranged at predetermined pitches in the circumferential direction, and the first fixed cam portion is predetermined in the circumferential direction. When having the plurality of recesses arranged at pitch intervals, and having a cam slope in each recess, and when the first rotating cam part swings in the axial centrifugal direction together with the lead core feed pipe, The sliding contact protrusion of the first rotating cam portion is in sliding contact with the cam slope of the first fixed cam portion, so that the first rotating cam portion is rotated in the one direction.

  In a more preferred form, an urging means for urging the lead core feed pipe in the axial tube centripetal direction is provided.

  In a more preferred embodiment, the biasing means is an annular elastic body provided between the lead core feed pipe and the shaft tube.

  In a more preferred form, when the lead core feed pipe is swung in the shaft tube centripetal direction by the biasing force of the biasing means, the chuck is rotated in the one direction by the swinging force.

  In a further preferred embodiment, a second rotating cam portion is provided rotatably on the outer periphery of the lead portion of the lead-core feeding tube on the rear side, and a second non-rotatable inner periphery of the shaft tube is provided. A fixed cam portion is provided, and the second rotating cam portion is slidably contacted with the second fixed cam portion when the second rotating cam portion is swung in the shaft centripetal direction together with the lead core feed pipe. Is rotated in the one direction, and the chuck is rotated by the rotation of the second rotating cam portion.

  In a further preferred form, the second rotating cam portion has a plurality of sliding contact projections arranged at predetermined pitches in the circumferential direction, and the sliding contact projections are used for swinging the lead core feed pipe. Along with the elastic deformation in the axial direction of the shaft cylinder, the second fixed cam portion is provided so as to always contact with the second fixed cam portion, and the second fixed cam portions are arranged at predetermined pitches in the circumferential direction. The second rotating cam portion has a plurality of recesses, and has a cam slope in each of the recesses, and the second rotating cam portion swings in the shaft centripetal direction together with the lead core feed pipe. Slidable contact projections slidably contact the cam slope of the second fixed cam portion, rotate the second rotating cam portion in the one direction, and rotate the chuck by the rotation of the second rotating cam portion. I did it.

  In a further preferred form, in the state where the sliding contact projection of the first rotating cam portion is locked in the recess of the first fixed cam portion, the sliding contact projection of the second rotating cam portion is the second rotating cam portion. It was positioned in the middle of the cam slope of the fixed cam part.

  In a further preferred form, the lead core supply pipe includes a front pipe part supported to be swingable with respect to the shaft cylinder, and a rear pipe part rotatably connected to the rear side of the front pipe part. The rear tube portion integrally includes the first rotating cam portion, the second rotating cam portion, and the chuck.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, “front” means the tip direction of the shaft tube 10 (downward according to FIG. 1), and “rear” means the direction opposite to the “front”.
In the present embodiment, the “lead core direction” means the longitudinal direction of the lead core 2 sandwiched between the chucks 24c (the vertical direction according to FIG. 1).

  The mechanical pencil 1 includes a shaft cylinder 10, a lead core feeding pipe 20 having a tip 20a projecting from the shaft cylinder 10, and an annular elastic body 30 that urges the lead core feeding pipe 20 in the shaft cylinder centripetal direction ( Urging means), and the swinging of the lead core feeding tube 20 is converted into a rotational movement around the lead core 2, and the lead core 2 is sandwiched in the lead core feeding tube 20 by the rotational motion. The chuck 24c to be rotated is rotated in one direction.

  The shaft cylinder 10 includes a long cylindrical main body portion 11 and a tapered cylindrical front end portion 12 screwed to the front end side of the main body portion 11. In addition, this axial cylinder 10 is good also as an aspect which united the main-body part 11 and the front-opening part 12, and the aspect which combined three or more members, such as a front axis | shaft and a rear axis | shaft.

The inner peripheral surface of the main body portion 11, the first fixed cam portion 11a and the second fixed cam portion 11b is integrally provided.

The first fixed cam portion 11a is formed in a cross-sectional saw blade shape having a plurality of concave portions 11a1 arranged at predetermined pitches in the circumferential direction (see FIG. 4).
Each recess 11a1 is a cam inclined surface 11a11 that is downwardly inclined toward the rotation direction of the lead core feed pipe 20 (counterclockwise in the illustrated example), and a shaft cylinder radial surface that intersects the cam inclined surface 11a11. It consists of a locking surface 11a12.
The width of the first fixed cam portion 11a in the axial tube axial direction is appropriately set so as to allow the first rotating cam portion 24a to move in the axial tube axial direction as the rear tube portion 24 advances and retreats. .

The second fixed cam portion 11b is formed in a cross-sectional chevron shape having a plurality of concave portions 11b1 arranged at predetermined pitches in the circumferential direction (see FIG. 4).
Each recess 11b1 includes a cam slope 11b11 that is inclined downward in the rotation direction of the lead core feed pipe 20 (counterclockwise in the illustrated example), and a latch that intersects the cam slope 11b11 in a substantially V shape. It consists of surface 11b12.
The width of the second fixed cam portion 11b in the axial tube axial direction is appropriately set so as to allow the second rotary cam portion 24b to move in the axial tube axial direction as the rear tube portion 24 advances and retreats. .

  Moreover, it has the cyclic | annular protrusion 12a which protrudes inward toward the centripetal direction of the axial cylinder 10 in the foremost end part of the front-end | tip part 12 (refer FIG. 1). The annular protrusion 12a is loosely fitted to a lead core feeding pipe 20 described later, thereby supporting the lead core feeding pipe 20 so that its tip side swings in a direction substantially perpendicular to the lead core direction. Yes.

Further, the lead core feeding tube 20 is configured so as to be fed from the distal end portion 20a by holding the lead core 2 in a non-rotatable manner by an inherent chuck mechanism, and the front side of the support portion A with respect to the shaft tube 10 is in the lead core direction. Is supported by the annular protrusion 12a at the foremost end of the shaft tube 10 so that the rear side of the support location A swings in the reverse direction.
The lead core feeding pipe 20 is integrally connected to a front side pipe part 21 supported so as to be swingable with respect to the shaft cylinder 10 with a tip part 20a protruding from the shaft cylinder 10 and a rear side of the front side pipe part 21. An intermediate pipe portion 22, a rear pipe portion 24 connected to a further rear side of the intermediate pipe portion 22 via an urging member 23 so as to be movable back and forth, and rotatable, and on the rear side of the rear pipe portion 24. It is formed in a long tubular shape having a core tank 25 connected thereto.

The front tube portion 21 is a tubular member having a tapered tip portion 20a on the front end side, and is an annular shape that is loosely fitted to the annular protrusion 12a at the front end of the tip portion 12 on the outer peripheral surface on the rear side of the tip portion 20a. A groove 21c is provided.
An appropriate gap is secured between the annular groove 21c and the annular protrusion 12a so that the lead core supply pipe 20 can swing with respect to the shaft tube 10.
A core breaker 21b made of an elastic body that holds the lead core 2 so as not to be retractable is provided on the front side in the front tube portion 21. A clutch ring 24d is provided on the rear side in the front tube portion 21 so as to advance and retract by a predetermined amount around the chuck 24c.

  The intermediate tube portion 22 is a tubular member that is connected and fixed to the rear end portion of the front tube portion 21 and extends rearward, and is inserted through an annular elastic body 30 described later.

The rear tube portion 24 is a stepped tubular member in which a reduced diameter portion 24e on the front portion side is inserted into the rear end side inside the intermediate tube portion 22, and can move forward and backward by a predetermined amount with respect to the intermediate tube portion 22. And engaged so as to be rotatable in the rotation direction around the lead core 2.
A chuck 24 c that clamps the lead core 2 is provided on the front end side of the rear pipe portion 24. A core tank 25 is connected to the rear end side inner peripheral surface of the rear pipe portion 24. A first rotating cam portion 24 a and a second rotating cam portion 24 b are integrally provided on the rear end side outer peripheral surface of the rear tube portion 24.

The chuck 24c includes a plurality of (for example, 2 or 3) claw portions 24c1 that are made of a synthetic resin material or a metal material having elasticity, and are arranged concentrically so as to be positioned around the lead core 2. The lead core 2 is clamped when the diameter of the claw portion 24c1 is reduced, and the lead core 2 is released when the diameter of the claw portion 24c1 is increased.
The chuck 24 c has a base end side portion (upper end side portion according to FIG. 1) fixed to the front end side inner peripheral surface of the rear tube portion 24.

Further, when the first rotating cam portion 24a swings together with the lead core feed pipe 20 in the axial centrifuge direction (in other words, the direction away from the center of the axial cylinder 10), the first rotating cam portion 24a The fixed cam portion 11a is in sliding contact with the fixed cam portion 11a so as to rotate in one direction.
The first rotating cam portion 24a includes a plurality of sliding contact protrusions 24a1 arranged at predetermined pitches in the circumferential direction. Each sliding contact protrusion 24a1 is a saw blade-like protrusion that follows the recess 11a1 of the first fixed cam portion 11a (see FIGS. 3 and 4).

The second rotating cam portion 24b is located on the rear side of the first rotating cam portion 24a, and a plurality of (three in the illustrated example) sliding contact protrusions 24b1 arranged at predetermined pitches in the circumferential direction. (See FIG. 3).
Each slidable protrusion 24b1 includes a protrusion 24b11 that is in slidable contact with the second fixed cam portion 11b, and an elastic deformation portion 24b12 that elastically advances and retracts the protrusion 24b11 in the axial cylinder radial direction (FIG. a) -II).
The protrusion 24b11 is formed in a mountain shape that follows the recess 11b1 of the second fixed cam portion 11b. The elastic deformation portion 24b12 is formed in a U shape that can be elastically deformed.
The sliding contact projection 24b1 elastically deforms the elastic deformation portion 24b12 in the axial cylinder radial direction along with the swinging of the lead core feed pipe 20, and always maintains the contact state between the protrusion 24b11 and the second fixed cam portion 11b. To do.

The positional relationship between the first rotating cam portion and the fixed cams 24a and 11a and the second rotating cam portion and the fixed cams 24b and 11b will be described. The sliding contact protrusion 24a1 of the first rotating cam portion 24a is the first rotating cam portion 24a and 11a. In a state where the recessed portion 11a1 of the fixed cam portion 11a is fitted and locked (see FIG. 4 (b) -I), the protrusion portion 24b11 of the sliding contact protrusion 24b1 of the second rotating cam portion 24b is the second fixed cam. It arrange | positions so that it may be located in the middle of the cam slope 11b11 of the part 11b (refer FIG.4 (b) -II).

Further, the urging member 23 is a compression spring, and is annularly attached to the reduced diameter portion 24e on the front side of the rear tube portion 24, and the step portion 24e1 at the rear end of the reduced diameter portion 24e and the rear end surface of the intermediate tube portion 22 are connected to each other. Stretch between.
The urging member 23 exerts an action of marching the rear pipe portion 24 after advancing by urging the rear pipe portion 24 backward with respect to the intermediate pipe portion 22. Further, the urging member 23 also reduces the rotational resistance (friction resistance) of the rear tube portion 24, and also has an effect of making the rear tube portion 24 easier to rotate with respect to the front tube portion 21 and the intermediate tube portion 22. .

  In the above-described configuration, the front tube portion 21 and the intermediate tube portion 22 may be rotatable or non-rotatable with respect to the shaft tube 10, but in particular, the first rotating cam portion 24a and the second rotation. From the viewpoint of reducing the rotational resistance of the cam portion 24b, the former mode is preferable. In this case, the annular groove 21c of the front tube portion 21 is slidably contacted with the annular protrusion 12a at the front end of the shaft tube 10, and the outer peripheral surface of the intermediate tube portion 22 is slidably contacted with the inner peripheral surface of the annular elastic body 30. What is necessary is just to set it as the structure which the part 21 and the intermediate pipe part 22 rotate with respect to the axial cylinder 10. FIG.

Further, a known lead lead feeding mechanism for feeding the lead lead 2 by advancing and retracting movement of the chuck 24c is formed inside the lead lead feeding tube 20.
The lead core feeding mechanism will be described in detail. When the rear tube portion 24 and the core tank 25 move forward against the urging force of the urging member 23 by the pressing force from the rear, the chuck 24c at the front end of the rear tube portion 24 is used. Advances with the lead core 2 sandwiched therebetween. As the chuck 24c advances, the clutch ring 24d fitted on the outer periphery of the chuck 24c also advances. When the clutch ring 24d comes into contact with the stepped portion 21a in the front pipe portion 21 by this advancement, the chuck 24c is released from the clutch ring 24d to the front, released, elastically expanded in diameter, and held between the lead cores. Release 2 The lead core 2 is clamped so as not to be retracted by the core breaker 21b in the front side pipe portion 21 at a position advanced together with the chuck 24c.
Next, when the pressing force from the rear is released, the rear tube portion 24 and the core tank 25 are retracted by the urging force of the urging member 23, and the chuck 24c is also retracted along with the retraction. Therefore, the diameter of the chuck 24c is reduced by fitting with the clutch ring 24d, and the lead core 2 is sandwiched again in the retracted position.
Therefore, the lead core 2 is fed out from the front end side of the chuck 24c by repeating the back and forth movement of the rear pipe portion 24, the chuck 24c, and the lead tank 25, and the lead core 2 is further connected to the tip end portion 20a of the lead core feed pipe 20. It will be drawn forward from.

  The structure for advancing and retracting the rear tube portion 24, the chuck 24c, and the core tank 25 includes, for example, a rear tube portion 24, a chuck 24c, and the like by knocking a knock portion (not shown) protruding rearward from the shaft tube 10. A mode in which the lead tank 25 is advanced and retracted, a mode in which the rear tube portion 24, the chuck 24c and the lead tank 25 are advanced and retracted by a knocking operation on a button (not shown) on the side surface of the shaft tube 10, and a weight by an operation in which the shaft tube 10 is shaken as a whole. For example, the body (not shown) can be reciprocated and the back tube 24, the chuck 24c, and the core tank 25 can be advanced and retracted by reciprocating the weight.

The annular elastic body 30 (biasing means) is an annular elastic body provided between the outer peripheral surface of the lead core feed pipe 20 and the inner peripheral surface of the shaft tube 10. The material of the annular elastic body 30 may be, for example, rubber, elastomer resin, sponge, or the like.
According to an example of the present embodiment, the elastic force of the annular elastic body 30 is applied to the lead core 2 protruding from the distal end portion 20a of the lead core feeding tube 20 in a normal writing posture in which the shaft tube 10 is inclined. When pressure is applied (see FIG. 2 (b)), the annular elastic body 30 is elastically deformed, and the lead core feed pipe 20 is set appropriately so that it swings around the support location A as a fulcrum. The

Next, the characteristic effect of the mechanical pencil 1 having the above configuration will be described in detail.
First, as shown in FIG. 1 and FIG. 2 (a), in the initial state where no writing pressure is applied to the lead core 2 protruding from the tip 20a of the lead core delivery pipe 20, the lead core delivery pipe 20 is an annular elastic body. It is held on the substantially center line of the shaft tube 10 by the urging force of 30.
In this initial state, as shown in FIG. 3 (a) -I, the first rotating cam portion 24a is positioned substantially on the center line of the shaft tube 10 and is held in a state not in contact with the first fixed cam portion 11a. Is done.
Further, in the same initial state, the second rotating cam portion 24b is positioned substantially on the center line of the shaft tube 10 as shown in FIG. 3 (a) -II, and a plurality of (three in the illustrated example) The sliding contact projections 24b1 are pressed against the second fixed cam portion 11b with substantially the same urging force, and the projection portions 24b11 of the respective sliding contact projections 24b1 are fixed to the second fixed portion as shown in FIG. 4 (a) -II. The cam portion 11b is fitted and locked in the recess 11b1.

Next, as shown in FIG. 2 (b), when the tip of the lead core 2 is pressed against the writing surface 3 in a normal writing posture in which the shaft cylinder 10 is inclined, the lead core feed pipe 20 has a position relative to the shaft cylinder 10. The portion on the rear side of the support location A swings and inclines in the axial direction of the axial cylinder (in the diagonally downward direction according to FIG. 2) relative to the axial cylinder 10.
At this time, as shown in FIG. 3 (b) -I, the first rotating cam portion 24a is slidably contacted with the first fixed cam portion 11a in a predetermined direction in one direction (counterclockwise in the illustrated example). Rotate. More specifically, as shown in FIG. 4 (b) -I, the first rotating cam portion 24a has a swinging direction (upward according to FIGS. 3 and 4) among the plurality of sliding contact projections 24a1. A part of the slidable contact protrusions 24a1 protruding to the slidable contact with the cam inclined surface 11a11 of the first fixed cam portion 11a facing each other rotates in the one direction. This rotation is stopped when the part of the sliding protrusion 24a1 of the first rotating cam portion 24a is fitted and locked in the concave portion 11a1 of the first fixed cam portion 11a.
Accordingly, the first rotating cam portion 24a, the rear tube portion 24, and the chuck 24c are integrally rotated by a predetermined angle, and the lead core 2 sandwiched between the chucks 24c is similarly rotated.
On the other hand, by the rotation, the protrusion 24b11 of each sliding contact protrusion 24b1 in the second rotating cam portion 24b gets over the top of the locking surface 11b12 of the second fixed cam portion 11b. Then, in the state where the rotation is stopped by the fitting of the first rotating cam portion 24a and the first fixed cam portion 11a, as shown in FIG. The stationary cam portion 11b is positioned in the middle of the cam slope 11b11 and is stationary.

When the tip of the lead core 2 is separated from the writing surface 3, the lead core feeding tube 20 is swung in the shaft tube centripetal direction (in other words, the direction approaching the center of the shaft tube 10) by the urging force of the annular elastic body 30. Move. By this swinging, the first rotating cam portion 24a is separated from the first fixed cam portion 11a (see FIG. 3 (c) -I). That is, the locked state by the fitting of the first rotating cam portion 24a and the first fixed cam portion 11a is released.
Then, the protrusion 24b11 of the sliding contact protrusion 24b1 in the second rotating cam portion 24b is slid by being pressed against the cam inclined surface 11b11 of the second fixed cam portion 11b by the elastic force of the elastic deformation portion 24b12. The second rotating cam portion 24b rotates in the one direction (counterclockwise in the illustrated example). This rotation is stopped by the sliding contact protrusion 24b1 being fitted and locked in the recess 11b1 of the second fixed cam portion 11b (see (a) -II in FIGS. 3 and 4).
Therefore, the rear tube portion 24 and the chuck 24c integrated with the second rotating cam portion 24b rotate by a predetermined angle, and the lead core 2 sandwiched between the chucks 24c also rotates in the same manner.

Therefore, according to the mechanical pencil 1 of the present embodiment, the lead core 2 protruding from the tip portion 20a of the lead core feeding tube 20 is pressed against the writing surface 3 in a normal writing posture in which the shaft tube 10 is inclined. The lead core 2 can be rotated by a predetermined angle by an operation of separating the lead core 2 from the writing surface 3.
Therefore, it is possible to solve the problem that the leading end portion of the lead core 2 is unevenly reduced by writing and the thickness and darkness of the drawn lines are not constant.
In addition, since the lead core 2 is rotated by transmitting the component of the pen pressure in the direction crossing the axis by utilizing the principle of the lever, the lead core 2 does not rattle in the axial direction, and the lead core 2 swings. Can be made relatively small, and the writing feel is good.

In addition, when the lead core 2 is pressed against the writing surface 3, the lead core 2 slightly swings. The swing amount at this time (movement distance on the arc with the support point A as a fulcrum) is By appropriately adjusting the distance X1 between the foremost end of the lead core feed pipe 20 and the support location A and the distance X2 (see FIG. 1) between the support location A and the first rotating cam portion 24a. Can be suppressed to the minimum necessary.
That is, the larger the ratio of the distance X2 to the distance X1, the larger the amount of swing of the first rotating cam portion 24a and the second rotating cam portion 24b can be secured, but the first rotating cam portion 24a. The pressing force at the time of sliding contact with the first fixed cam portion 11a becomes small.
Therefore, in the present embodiment, the writing feel is not impaired by the swing of the lead core 2, and the first rotating cam portion 24a and the second rotating cam portion 24b can be smoothly rotated. The ratio of the distance X2 to the distance X1 is appropriately set.

  In addition, according to the said embodiment, although the 2nd rotation cam part 24b was arrange | positioned in the back side of the 1st rotation cam part 24a, as another example, it is also possible to reverse the front-back relationship. .

In addition, according to the above embodiment, the lead core 2 is rotated by applying normal writing pressure. However, as another example, if the elastic force of the annular elastic body 30 is increased, a normal writing brush is used. It is also possible to adopt a configuration in which the lead core 2 rotates by applying a pressing force equal to or higher than the pressure.
According to this configuration, when the writer wants to rotate the lead core 2, the lead core 2 rotates when a pressing force higher than the normal writing pressure is consciously applied as necessary. Become.

  Moreover, according to the said embodiment, although the cyclic | annular elastic body 30 was arrange | positioned ahead of the 1st rotation cam part 24a and the 2nd rotation cam part 24b, as another example, the cyclic | annular elastic body 30 is 1st. It is also possible to arrange the rotary cam portion 24a and the second rotary cam portion 24b on the rear side or between the first rotary cam portion 24a and the second rotary cam portion 24b.

  Further, as an urging means replacing the annular elastic body 30, another type of elastic body such as a leaf spring can be provided between the outer peripheral surface of the lead core feed pipe 20 and the inner peripheral surface of the shaft cylinder 10.

  As still another example, the annular elastic body 30 is omitted, and the lead core feed pipe 20 is urged in the shaft centripetal direction only by the elastic force of the elastic deformation portion 24b12 of the second rotating cam portion 24b. It is also possible.

  Moreover, in the said embodiment, as the preferable aspect which reduces the rotational resistance of the 1st rotation cam part 24a and the 2nd rotation cam part 24b, the rear side pipe part 24 is compared with the front side pipe part 21 and the intermediate | middle pipe part 22. Although it was set as the structure rotated, as another example, the aspect in which the front side pipe part 21, the intermediate | middle pipe part 22, and the rear side pipe part 24 rotate integrally, ie, the lead core supply pipe | tube 20 whole, rotates with respect to the axial cylinder 10. It is also possible to adopt an aspect.

Moreover, in the said embodiment, as a preferable example which made the lead core 2 rotate smoothly, the 1st rotation cam part 24a and the 1st fixed cam part 11a, the 2nd rotation cam part 24b, and the 2nd fixed is provided with the two types of cams and cam portion 11b, as another example, omitting the second rotating cam portion 24b and the second fixed cam portion 11b, the first rotating cam portion 24a and the first A configuration in which the lead core 2 is rotated only by the fixed cam portion 11a is also possible.

Moreover, in the said embodiment, although the 1st fixed cam part 11a and the 2nd fixed cam part 11b were comprised integrally with the axial cylinder 10, as another example, the 1st fixed cam part and the axial cylinder 10 are separate bodies. The fixed cam portion 11 a and / or the second fixed cam portion 11 b may be fixed to the shaft tube 10.

1: Mechanical pencil 2: Lead core 3: Writing surface 10: Shaft cylinder 11a: First fixed cam portion 11a1: Recess 11a11: Cam slope 11b: Second fixed cam portion 11b1: Recess 11b11: Cam slope 20: Lead Core feed pipe 20a: tip 24c: chuck 24a: first rotating cam 24a1: sliding contact 24b: second rotating cam 24b1: sliding contact 24b11: protruding 24b12: elastic deformation 30: annular elastic body

Claims (7)

Sharp equipped with a shaft cylinder and a lead core feeding pipe having a tip protruding from the shaft cylinder, the lead core in the lead core feeding pipe being unrotatably held by a chuck and fed out from the tip In the pencil,
An annular protrusion provided on the shaft tube is loosely fitted in an annular groove provided on a front tube portion of the lead core feeding tube, so that the lead core feeding tube is a lead core on the front side of the loose fitting portion. Supports the rear side to swing in the opposite direction from the loose fit as it swings in the direction intersecting the direction ,
A first rotating cam portion is provided on the outer periphery on the rear side of the lead fitting pipe in the lead core feeding pipe so as to be rotatable with respect to the front pipe section, and on the inner periphery of the shaft cylinder, A first fixed cam portion that cannot rotate is provided,
Fixing the chuck to the first rotating cam so as to be integrally rotatable;
The first rotating cam portion is slidably contacted with the first fixed cam portion when the lead core feeding tube is swung in the axial centrifugal direction, and the first rotating cam portion is rotated in one direction. The mechanical pencil is characterized in that the chuck is rotated by the rotation of the first rotating cam portion . The first rotating cam portion has a plurality of sliding contact projections arranged at predetermined pitches in the circumferential direction,
The first fixed cam portion has a plurality of recesses arranged at predetermined pitches in the circumferential direction, and has a cam slope in each recess.
When the first rotating cam portion swings in the axial cylinder centrifugal direction together with the lead core feed pipe, the sliding contact protrusion of the first rotating cam portion comes into sliding contact with the cam inclined surface of the first fixed cam portion. The mechanical pencil according to claim 1, wherein the first rotating cam portion is rotated in the one direction . The mechanical pencil according to claim 1 or 2, further comprising an urging means for urging the lead core feeding pipe in a centripetal direction . 4. The mechanical pencil according to claim 3, wherein the biasing means is an annular elastic body provided between the lead core feed pipe and the shaft tube . A second rotating cam portion is provided integrally with the first rotating cam portion on the outer periphery on the rear side of the first rotating cam portion in the lead core feed pipe, and on the inner periphery of the shaft tube The second fixed cam portion is provided integrally with the first fixed cam portion on the rear side of the first fixed cam portion,
When the lead core feed pipe is swung in the shaft centripetal direction by the urging force of the urging means, the second rotating cam portion is swung in the shaft centripetal direction together with the lead core feed pipe. The second rotating cam portion is slidably contacted with a second fixed cam portion, the second rotating cam portion is rotated in the one direction, and the chuck is rotated by the rotation of the second rotating cam portion. The mechanical pencil according to claim 3 or 4 . The second rotating cam portion has a plurality of sliding contact projections arranged at predetermined pitches in the circumferential direction, and the sliding contact projections are arranged in the axial cylinder radial direction along with the swinging of the lead core feed pipe. By being elastically deformed, it is provided so as to always contact the second fixed cam part,
The second fixed cam portion has a plurality of recesses arranged at predetermined pitches in the circumferential direction, and has a cam slope in each recess.
In a state where the sliding contact protrusion of the first rotating cam portion is locked in the recess of the first fixed cam portion, the sliding protrusion of the second rotating cam portion is the cam of the second fixed cam portion. When the second rotating cam portion swings in the shaft centripetal direction together with the lead core feed pipe at the position in the middle of the slope, the sliding protrusion of the second rotating cam portion Slidably contacted with the cam slope of the second fixed cam portion, the second rotating cam portion is rotated in the one direction, and the chuck is rotated by the rotation of the second rotating cam portion. The mechanical pencil according to claim 5 . The lead core feed pipe includes a rear pipe portion rotatably connected to a rear side of the front pipe portion, and the rear pipe portion includes the first rotary cam portion and the second rotary cam portion. The mechanical pencil according to claim 5 or 6, wherein the chuck is integrally formed .

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