JP2015020420A - Shaking-out type mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely achieve the delivery function of a writing lead, in a shaking-out type mechanical pencil delivering a writing lead by inertial force of a weight body by shaking a barrel.SOLUTION: A weight body is slidably loaded between a barrel 1 and lead cases 4A and 4B for storing a preliminary writing lead, and a chuck 7 for gripping the writing lead moves forward, and the writing lead is delivered, by the inertial force of the weight body generated by shaking the barrel. A volute spring 16 is used as the weight body, and this volute spring is wound in a spiral shape by successively diametrically expanding the long side by using a rectangular metallic base material 16A. A clearance 16c is also formed between layers of the base material in the orthogonal direction to the slide direction, and thereby, the volute spring 16 is constituted so as to be compressible in the slide direction, and effectively functions as a lead breaking countermeasure by absorbing impact when shaking out.

Description

  The present invention relates to a swing-out type mechanical pencil capable of feeding out a writing core by utilizing an inertia force of a weight body generated by shaking a shaft cylinder.

  In the swing-out mechanical pencil, a weight body (weight) formed, for example, in a cylindrical shape is arranged to be slidable in the axial direction between a shaft cylinder and a core case that houses a spare writing core. Then, utilizing the inertial force of the weight body generated by shaking the shaft cylinder, the chuck for gripping the writing core is moved forward to open instantaneously and operate to feed out the writing core.

As the above-mentioned weight body, it is necessary to secure a certain amount of weight in order to provide an operation of momentarily opening the chuck by inertia force, and for example, a pipe-shaped metal cylinder is frequently used.
When a metal cylinder is used as the weight body, a certain amount of weight can be secured, but the impact of the weight body acts greatly, which causes a problem of breaking the writing core.
For this reason, Patent Document 1 discloses a mechanical pencil that is provided with an impact absorber that absorbs the impact of a heavy body when it is swayed, and that has taken measures against core breakage.

According to the swing-out mechanical pencil disclosed in Patent Document 1, two rubber O-rings are prepared as shock absorbers that absorb the impact of a heavy body, and one of the O-rings is a chuck at the front end of the core case. A configuration is employed in which the other O-ring is mounted on a core surrounding the rear end of the core case.
According to the mechanical pencil disclosed in Patent Document 1, it is necessary to prepare the O-ring as an impact absorber, and problems such as an increase in the number of parts and an increase in assembly man-hours remain.

On the other hand, Patent Document 2 discloses a swing-out type mechanical pencil in which a linear coil spring is formed by winding a wire in a coil shape and this is used as a weight body.
According to the swing-out mechanical pencil disclosed in Patent Document 2, it is difficult to increase the weight of the coil spring. Therefore, a wire rod wound in a coil shape has a rectangular cross section. ing.
According to this, it is described that the weight can be increased as compared with a coil spring made of a wire having a circular cross section.

  In Patent Document 2, the center portion of the coil spring is wound in a close contact state, and both end portions of the coil spring have a slightly large gap between the coils. It is described that it functions effectively as an impact absorber that absorbs the impact at the time of shaking.

  According to the configuration disclosed in Patent Document 2, the increase in the number of parts and assembly man-hours can be eliminated as compared with the mechanical pencil disclosed in Patent Document 1, but the cross section of the wire wound in a coil shape In the range of the shape change, it cannot be expected to increase the weight as much.

In particular, when the cross-sectional area of the wire wound in a coil shape is increased, the spring constant of the spring as the shock absorber is extremely increased. Results in a decline.
In addition, in order to secure the overall weight by the linear coil spring, the length dimension in the axial direction (sliding direction) needs to be set to be somewhat large. In this case, the length dimension in the axial direction of the coil spring increases. As a result, the design constraint that the moving stroke of the coil spring is reduced also emerges. For this reason, the problem that the writing-out function of a writing core cannot be fully performed arises.

JP 2013-1020 A JP 2011-83988 A

By the way, the present applicant has previously proposed a mechanical pencil equipped with a rotation drive mechanism that can gradually rotate the writing core (replacement core) in one direction using the writing pressure. The rotational drive mechanism is disposed behind the chuck.
Accordingly, when the mechanical pencil having the lead rotation driving mechanism is also provided with the above-mentioned swing-out function, it is more difficult to secure the moving stroke in the axial direction of the weight body, and the axial length dimension of the weight body. Setting a smaller value is an important issue.

  For the reasons described above, the weight body used in this type of swing-out mechanical pencil has a small length in the axial direction (sliding direction) and a large overall weight, and further measures against core breakage. It is ideal that one part has an appropriate spring effect that can be compressed in the axial direction.

  The present invention has been made based on the technical viewpoint described above, and by loading a weight body (weight) having the above-described conditions in a slidable manner between the shaft tube and the core case, It is an object of the present invention to provide a swing-out type mechanical pencil that can solve the problems of the mechanical pencils disclosed in Patent Documents 1 and 2.

  The basic form of the mechanical pencil according to the present invention made to solve the above-mentioned problem is that a weight body is slidably loaded between a shaft cylinder and a core case that houses a spare writing core, and the shaft cylinder is mounted. A mechanical pencil that moves forward a chuck for gripping the writing core by the inertial force of the weight body generated by shaking, and feeds out the writing core, and uses a bamboo spring or a conical coil spring as the weight body. Features.

In this case, the bamboo spring is formed by spirally winding a long side with a rectangular base material and increasing the diameter sequentially, and forming a gap between the base materials in a direction perpendicular to the sliding direction. By doing so, it is desirable to be configured to be compressible in the sliding direction.
Further, the conical coil spring can be compressed in the sliding direction by winding the coil diameter sequentially using a wire and spirally winding it, and forming a gap between the coils adjacent to the sliding direction. It is desirable to be configured.

Further, in a preferred embodiment using a bamboo shoot spring as a weight body, one end portion of the bamboo shoot spring protruding toward the axial center side with a small helical diameter is loaded into the shaft cylinder toward the front where the chuck is disposed. Configuration is adopted.
On the other hand, in a preferred embodiment using a conical coil spring as the weight body, one end portion of the conical coil spring that protrudes toward the axial center side with a small coil diameter is loaded into the shaft cylinder toward the front where the chuck is disposed. The adopted configuration is adopted.

  In addition, each form of the above-described swing-out mechanical pencil includes a rotation drive mechanism that rotates the rotating cam based on the writing pressure received by the writing core, and is configured to transmit the rotational motion of the rotating cam to the writing core. Therefore, it can be suitably used for a mechanical pencil, thereby providing a swing-out mechanical pencil with more enhanced functions.

According to the above-described swing-out type mechanical pencil according to the present invention, a bamboo spring or a conical coil spring is used as a weight body for moving the chuck for gripping the writing core forward by an inertial force. These bamboo springs and conical coil springs can ensure a large overall weight while forming a small axial length.
In addition, since an appropriate spring effect that can be compressed in the axial direction can be provided, an ideal action can be exhibited as a measure against breakage of the core of this type of swing-out mechanical pencil.

Moreover, the above-mentioned swing-out function can be suitably employed in a mechanical pencil having a rotation drive mechanism that gradually rotates the writing core in one direction based on the writing pressure received by the writing core.
In this case, the limitation of the moving stroke of the weight body due to the presence of the rotation drive mechanism can be compensated by taking advantage of the characteristic of the weight body that the length in the axial direction can be reduced.

It is the expanded sectional view which divided and showed the 1st form of the mechanical pencil concerning this invention front and back. It is an expanded sectional view of the state rotated 90 degree | times from the state shown in FIG. It is sectional drawing which showed the whole structure of the state which moved the weight body to the rear part. It is the front view and center sectional view which expanded and showed the example of the bamboo shoot spring utilized as a weight body. It is a front view of the holder member which comprises a rotation drive mechanism. FIG. 6 is a central sectional view of the holder member shown in FIG. 5. It is a front view of the rotation drive mechanism which attached the rotation cam to the holder member. FIG. 8 is a central sectional view of the rotation drive mechanism shown in FIG. 7. It is the expanded sectional view which divided and showed the 2nd form of the mechanical pencil front and back. It is the front view and center sectional view which expanded and showed the example of the conical coil spring utilized as a weight body.

A mechanical pencil according to the present invention will be described based on an embodiment shown in the drawings.
In the following drawings, the same part or the part that performs the same function is indicated by the same reference numeral. However, for convenience of the drawing, a part of the drawing is given a reference numeral, and its detailed configuration is shown. May be described with reference to the reference numerals attached to other drawings.

  First, FIG. 1 to FIG. 8 show a first embodiment, which uses a bamboo spring as a weight body for moving the chuck forward by inertial force, and writing based on the writing pressure received by the writing core. It shows a mechanical pencil equipped with a rotation drive mechanism that gradually rotates the lead in one direction.

As shown in FIG. 1 and FIG. 2, the tip member 3 to which the decorative ring 2 is attached is screwed to the tip of the shaft tube 1, so that the tip member 3 is detachably attached to the shaft tube 1. It has been. The first and second core cases 4A and 4B formed in a cylindrical shape along the shaft core of the shaft tube 1 are accommodated.
The first and second core cases 4A and 4B are linearly connected in the axial direction with a cylindrical connecting member 5 formed of synthetic resin as a center, and the center connecting member 5 has a weight described later. It functions as a receiving portion (a stopper for the advance position of the bamboo shoot spring) of the bamboo shoot spring as a body.

A short shaft core case joint 6 is attached to the tip of the first core case 4 </ b> A, and a brass chuck 7 is connected through the core case joint 6.
In the chuck 7, a writing core through-hole (not shown) is formed along the axis, and the tip of the chuck 7 is divided into a plurality (for example, three) in the circumferential direction. The part is loosely fitted in a fastener 8 formed in a ring shape by brass. Further, the ring-shaped fastener 8 is attached to the inner surface of the distal end portion of the rotary cam 23 constituting a part of the rotation drive mechanism 21 arranged so as to cover the periphery of the chuck 7.

A slider 9, which is accommodated in the above-described tip member 3 and protrudes from the tip member 3, is fitted to the front end portion of the rotating cam 23 so as to cover the outer peripheral surface of the rotating cam 23. Further, a tip pipe 11 for guiding the writing core is attached to the front end portion of the slider 9 via a pipe holder 12.
Further, a rubber holding chuck 13 having a through hole formed in the shaft core portion is mounted immediately after the tip pipe 11 on the inner peripheral surface of the slider 9.

  With the configuration described above, a linear core insertion leading to the distal end pipe 11 through a through hole formed in the chuck 7 following the first core case 4A and a through hole formed in the shaft core of the holding chuck 13 is performed. A hole is formed, and a writing core (not shown) is inserted into the linear core insertion hole. A coiled chuck spring 14 is disposed between the rotating cam 23 and the core case joint 6.

  The chuck spring 14 is in contact with the annular step formed on the inner peripheral surface of the rotary cam 23 at the front end thereof, and the rear end of the chuck spring 14 is in contact with the front end surface of the core case joint 6. Is housed in. Therefore, the chuck 7 is retracted in the rotary cam 23 by the axially expanding action of the chuck spring 14 and the tip of the chuck 7 is accommodated in the ring-shaped fastener 8, that is, the writing core. It is biased in the gripping direction.

The writing core rotation drive mechanism 21 including the rotation cam 23 is configured by a holder member 22 on the outer periphery thereof, and the rotation cam 23 formed in a columnar shape is rotatable on the front half of the holder member 22. It is mounted so that it can slide slightly in the axial direction.
A cushion member 24 formed of a rubber material (elastomer) is mounted immediately after the mounting position of the rotating cam 23 in the holder member 22, and the cushion member 24 is connected to the rotating cam 23. A sliding member (also referred to as a torque canceller) 25 is attached.

The torque canceller 25 is formed in a ring shape, abuts against the rear end surface of the rotary cam 23, and exerts an action of pushing the rotary cam 23 forward in the axial direction by the elasticity of the cushion member 24.
On the other hand, immediately after the mounting position of the cushion member 24 in the holder member 22, a plurality of slits 22a are formed in the circumferential direction to form a bellows shape, and the spring body 22b is configured by this bellows structure. . In addition, an annular undercut portion 22c is formed immediately after the spring body 22b, and the holder member 22 is fitted and fixed in the shaft tube 1 by the undercut portion 22c.

  When the above-described annular undercut portion 22c is fitted in the shaft cylinder 1, the front half portion of the holder member 22 that supports the rotating cam 23 is directed forward by the action of the spring body 22b immediately before it. To push out. As a result, a part of the holder member 22 is brought into contact with the stepped portion 1a (see FIG. 2) formed in the shaft cylinder, thereby positioning the rotary drive mechanism 21 including the rotary cam 23.

The latter half of the holder member 22 with the undercut portion 22c as a boundary forms a guide tube 22d along the shaft tube 1, and the guide tube 22d is a connecting member for the core cases 4A and 4B. 5 is formed, and a slide space for the bamboo spring 16 that functions as a weight body is formed.
That is, the bamboo spring 16 is loaded in the second core case 4B so that the center through hole is inserted and the second core case 4B serves as an axis and can slide in the guide tube 22d in the axial direction. Yes.

With this configuration, the bamboo spring 16 is moved forward so that one end projecting toward the axial center having a small helical diameter contacts the connecting member 5 as shown in FIGS. 1 and 2.
In addition, with the bamboo shoot spring 16 retracted, as shown in FIG. 3, the other end of the ring having a large spiral diameter is configured to come into contact with the front end of a knock bar 32 described later.
In other words, in this embodiment, the bamboo spring 16 is loaded so as to reciprocate between the connecting member 5 and the knock bar 32.
In addition, the further detailed structure of the said bamboo shoot spring 16 used in this embodiment is demonstrated later based on FIG.

On the other hand, the shaft core portions of the rotating cam 23, the cushion member 24, and the torque canceller 25 are formed in a space portion through which the first core case 4A is passed, thereby the first and second core cases 4A and 4B and the chuck. 7 etc. are independently movable in the axial direction.
The rotation drive mechanism 21 is unitized with a holder member 22, a rotation cam 23, a cushion member 24, a torque canceller 25, and the like. The configuration of the unitized rotation drive mechanism 21 is shown in FIG. Details will be described later with reference to FIG.

As shown in FIG. 2, a cylindrical clip support 31 having a clip 31 a formed integrally with the rear end portion of the shaft tube 1 is fitted and attached to the inner peripheral surface of the shaft tube 1. ing. Further, a knock bar 32 formed in a cylindrical shape along the inside of the clip support 31 is mounted. A front end portion of the knock bar 32 and a rear end portion (guide tube 22d) of the holder member 22 described above are provided. A shaft spring 33 is mounted between them, and the shaft spring 33 provides an action of projecting the knock bar 32 toward the rear portion of the shaft tube.
The step 32c having a larger outer diameter of the knock bar 32 is in axial contact with a part of the inner peripheral surface of the clip support 31 to form a mechanism for preventing the knock bar 32 from coming off. At the same time, the knock bar 32 is positioned.

  An eraser 34 is detachably attached to the rear end portion of the knock bar 32, and a knock cover 35 covering the eraser 34 is detachably attached to the peripheral surface of the rear end portion of the knock bar 32. A writing core replenishing hole 32a having a small diameter is formed at the position where the eraser 34 is mounted on the knock bar 32, and a contact portion 32b is formed so as to be orthogonal to the axial direction immediately before the hole.

In addition, the contact portion 32b formed on the knock bar 32 and the rear end portion of the second core case 4B are opposed to each other at a predetermined interval in the axial direction.
According to this configuration, even if the chuck 7 and the core cases 4A and 4B are slightly retracted due to writing, the rear end portion of the second core case 4B does not collide with the knock bar 32, and the rotation drive mechanism 21 It is possible to avoid obstructing the rotation operation.

In the above configuration, when the knock cover 35 is knocked, the shaft spring 33 contracts, and the abutting portion 32b of the knock bar 32 is connected linearly by the connecting member 5. The second core cases 4A and 4B are pushed forward.
Thereby, the chuck 7 moves forward and pushes the slider 9 slightly forward. However, since a part of the slider 9 comes into contact with the tip member 3 to prevent its advance, the tip of the chuck 7 protrudes relatively from the fastener 8 and the gripping state of the writing core by the chuck 7 is released.
By releasing the knocking operation, the knock cover 35 is retracted to the original state by the action of the shaft spring 33, and the chuck 7 and the core cases 4A and 4B are also moved into the shaft cylinder 1 by the action of the chuck spring 14. Retreat at.

At this time, the writing core is temporarily held by friction in the through hole formed in the holding chuck 13, and in this state, the chuck 7 is retracted and the tip thereof is accommodated in the fastener 8. Then, the writing core is again held.
That is, the chuck 7 is moved back and forth by repeating the knocking operation of the knock cover 35, whereby the writing core is released and gripped, and the writing core acts so as to be sequentially fed forward from the chuck 7.

In this mechanical pencil, when the shaft cylinder 1 is shaken, the bamboo spring 16 that functions as a weight body collides with the cylindrical connecting member 5 that connects the core cases 4A and 4B by inertial force.
In response to this action, the chuck 7 moves forward via the first core case 4A and the core case joint 6, and its tip protrudes relatively from the fastener 8 so that the chuck 7 is instantaneously opened. By repeating this operation, the writing core is sequentially drawn out from the chuck 7.

FIG. 4 is an enlarged view of the bamboo shoot spring 16 used in this embodiment. In the present invention, the “bamboo spring” refers to a “conical coil spring in which the long side of a material having a rectangular cross section is parallel to the coil center line” as defined in JIS B 0103-2012 classification 3300.
In the bamboo child spring 16 shown in FIG. 4, the long side is wound in a spiral shape with a diameter gradually increased using a rectangular metal base material 16 </ b> A. Therefore, the bamboo shoot spring 16 can ensure a large overall weight while forming a small axial length.

As described above with reference to FIGS. 1 to 3, the bamboo spring 16 is loaded such that the central through hole 16 a is inserted into the second core case 4 </ b> B and is slidable in the axial direction. In addition, as already described, the bamboo spring 16 is loaded so that one end 16b protruding toward the axial center having a small helical diameter comes into contact with the connecting member 5 that connects the core cases 4A and 4B.
Accordingly, since the inertial force accompanying the forward movement of the bamboo shoot spring 16 acts on a portion near the shaft core of the core case, the postures of the first and second core cases 4A and 4B are not displaced from the shaft core. It moves forward smoothly along and acts to push out the chuck 7 effectively.

In addition, it is desirable that the bamboo spring 16 used in this embodiment has a gap 16c formed between layers of the base material 16A in a direction orthogonal to the axial direction (sliding direction).
With this configuration, the bamboo shoot spring 16 can be compressed in the sliding direction and can have an appropriate spring effect in the sliding direction, so that the impact caused by the inertial force of the bamboo shoot spring 16 can be effectively reduced. Therefore, this type of swing-out mechanical pencil can sufficiently exhibit the effect as a countermeasure against breakage of the core.

5 and 6 show a detailed configuration of the holder member 22 that forms the outline of the rotation driving mechanism 21 of the writing core, and the cushion member 24 and the torque canceller 25 that are mounted on the holder member 22.
The holder member 22 is formed of a synthetic resin, and the holder member 22 is formed with a cylindrical portion 22e on the front side. The cylindrical portion 22e functions to support the rotary cam 23 so that the inner circumferential surface can rotate and move in the axial direction.

  A pair of elastic members 22f, which are long in the axial direction, are formed at axially symmetrical positions (positions facing each other by 180 degrees) on the front end side of the cylindrical portion 22e in a state where the holder member 22 is mounted in the shaft cylinder 1. ing. The pair of elastic members 22f are integrally formed with the above-described cylindrical portion 22e by resin molding, and are provided with an elastic action by being formed elongated.

A large number of cams (hereinafter referred to as first fixed cams) formed in a sawtooth shape continuously in an annular shape on the base end portion of the pair of elastic members 22f on the cylindrical portion 22e side, that is, on the end surface of the cylindrical portion 22e .) 22 g is formed.
Further, cams (which are referred to as second fixed cams) 22h each formed in a sawtooth shape are formed at the distal ends of the pair of elastic members 22f.
The second fixed cam 22h is formed on an inclined surface that is bent at a slight obtuse angle from the longitudinal end of the elastic member 22f toward the axis.

A pair of columnar bodies 22i extending in the axial direction are formed at axially symmetrical positions on the other end side of the cylindrical portion 22e described above, and the second cylindrical portion 22j is formed via the columnar bodies 22i. .
In addition, in the region surrounded by the pair of columnar bodies 22i and the second cylindrical portion 22j in the holder member 22, as described above, the cushion member 24 formed of a rubber material, preferably TPE (thermoplastic elastomer). A resin torque canceller 25 is attached via the cushion member 24.

In this embodiment, the cushion member 24 is integrally formed by two-color molding between the holder member 22 and the torque canceller 25 using the holder member 22 and the torque canceller 25 as a primary molded body. Reference numeral 24a denotes a gate position for TPE injection when performing two-color molding.
In addition, the cushion member 24 has a thin film body 24b formed at the center as shown in FIG. 6, and the thin film body 24b operates so that the elastomer forming itself deforms while being stretched in the axial direction. To do.

  On the torque canceller 25, hemispherical small protrusions 25a are formed on the opposite surface of the cushion member 24 at substantially equal intervals in the circumferential direction. These small protrusions 25a abut against the rear end portion of the rotating cam 23 by the action of the cushion member 24 described above, and slide between the rear end surface of the rotating cam 23 while giving the action of pushing the rotating cam 23 forward. To function.

FIGS. 7 and 8 show a state in which the unitized rotation drive mechanism 21 is configured by mounting the rotation cam 23 in front of the holder member 22 in the axial direction.
The rotary cam 23 is formed in a cylindrical shape, the center portion is a large diameter portion, and a plurality of sawtooth cams 23a are continuously formed in an annular shape on upper and lower surfaces orthogonal to the axis of the large diameter portion. , 23b are formed. Hereinafter, the cam 23a meshing with the first fixed cam 22g of the holder member 22 is referred to as an upper cam, and the cam 23b meshing with the second fixed cam 22h is referred to as a lower cam.

  Then, by pushing the rotating shaft 23c of the rotating cam 23 from the side of the pair of elastic members 22f formed on the holder member 22, the pair of elastic members 22f are spread outward and the rotating shaft 23c is a cylindrical portion. 22e. Thereby, the rotating cam 23 is mounted so as to be rotatable with respect to the holder member 22 and movable in the axial direction.

  In this embodiment, the lower cam 23b is formed on an inclined surface formed in a conical shape, and the second fixed cam 22h meshing with the lower cam 23b is in the longitudinal direction of the elastic member 22f as described above. It is formed on an inclined surface that is bent at an obtuse angle slightly toward the axis from the tip. Therefore, according to this embodiment, the rotary cam 23 is urged forward in the axial direction by the action of the cushion member 24 described above, so that the ideal axis in which the axis of the rotary cam 23 coincides with the axis of the holder member 22 is ideal. The meshing state can be realized.

  And the holder member 22 which comprises the outline of the said rotational drive mechanism 21 is inserted from the rear-end part side of the axial cylinder 1, and as already demonstrated based on FIGS. 1-3, the under member formed in the holder member 22 is already demonstrated. The rotational drive mechanism 21 is mounted at a predetermined position in the shaft cylinder 1 by fitting the cut portion 22 c at a predetermined position in the shaft cylinder 1.

  According to the rotation driving mechanism 21 of the writing core configured as described above, the rotating cam 23 is centered on the shaft core together with the chuck 7 in a state where the chuck 7 holds the writing core as shown in FIGS. And is made rotatable. When the mechanical pencil is in a state other than the writing state, the rotating cam 23 is urged forward through the torque canceller 25 by the action of the cushion member 24 disposed in the rotation driving mechanism 21. Yes.

  On the other hand, when a writing pressure is applied to the writing core protruding from the distal end pipe 10 by a writing operation, the chuck 7 is slightly retracted against the urging force of the cushion member 24, and accordingly the rotating cam 23 also retracts slightly in the axial direction. Therefore, the serrated upper cam 23a formed on the rotating cam 23 is joined to the first fixed cam 22g.

  In this case, the upper cam 23a and the first fixed cam 22g facing each other are set so as to have a half-phase (half-pitch) shifted relationship with respect to one cam tooth in the axial direction. When the upper cam 23a is joined to the first fixed cam 22g and engaged with each other, the rotating cam 23 receives rotational driving corresponding to one half phase (half pitch) of the upper cam 23a.

  In the state where the upper cam 23a is engaged with the first fixed cam 22g as described above, the saw-toothed lower cam 23b and the second fixed cam 22h facing each other are in the axial direction. The cam is set so as to have a half-phase (half-pitch) deviation from one cam tooth.

  Therefore, when the writing of one stroke is finished and the writing pressure on the writing core is released, the rotating cam 23 is pushed forward in the axial direction by the action of the cushion member 24 and is formed in the rotating cam 23. The lower cam 23b thus engaged meshes with the second fixed cam 22h. As a result, the rotating cam 23 is again subjected to rotational driving in the same direction corresponding to a half phase (half pitch) of one tooth of the lower cam 23b.

As described above, according to the above-described mechanical pencil, the rotary cam 23 has one tooth of the upper cam 23a and the lower cam 23b as the rotary cam 23 is reciprocated in the axial direction (cushion operation) by receiving the writing pressure. The writing core held by the chuck 7 via the chuck 7 is also rotated in one direction in the same manner.
Therefore, the tip of the writing core is always conical due to the rotational movement received by itself and the wear caused by writing. Therefore, it is possible to prevent the writing core from being unevenly worn as the writing progresses, and writing with a stable line width is possible.

  According to the first embodiment of the mechanical pencil according to the present invention described above, since the bamboo child spring is used as the weight body for moving the chuck for gripping the writing core forward by the inertial force, It is possible to ensure a large weight while forming the length dimension small. Therefore, an ideal function can be exhibited as this type of swing-out mechanical pencil.

  In addition, a rotation drive mechanism that gradually rotates the writing core in one direction based on the writing pressure received by the writing core can prevent uneven wear of the writing core, and writing with a stable line width is possible. is there. Moreover, the effect as described in the column of the effect of the above-mentioned invention can be obtained, for example, the restriction of the moving stroke of the weight body due to the presence of the rotation drive mechanism can be covered by the adoption of the bamboo spring.

Next, FIGS. 9 and 10 show a second embodiment, in which a conical coil spring is used as a weight body for moving the chuck forward by inertia force. In the second embodiment, the writing core rotation driving mechanism employed in the first embodiment is not mounted.
In FIG. 9, parts that perform the same functions as those in the first embodiment described above are denoted by the same reference numerals, and thus detailed description thereof is omitted.

  The shaft cylinder shown in FIG. 9 includes a front shaft 1A and a rear shaft 1B, and the front shaft 1A and the rear shaft 1B are connected via a central retaining ring 41. A covering rubber 42 is attached so as to surround and flex the peripheral surface of the front shaft 1A, and the covering rubber 42 forms a grip portion by sealing the gel agent 43.

A relatively long joint member 44 is disposed outside the core case 4, and a front end portion of the joint member 44 is connected to the chuck 7. A conical coil spring 45 that functions as a weight body is slidably disposed immediately after the joint member 44.
That is, the conical coil spring 45 is accommodated so as to reciprocate in the axial direction between the joint member 44 and the inner peripheral surface of the inner retaining ring 46 located at the rear part thereof.
The conical coil spring 45 is slidably loaded with the core case 4 as an axis, with a central through hole inserted into the core case 4.

With this configuration, in a state in which the conical coil spring 45 has advanced, one end portion that protrudes toward the axial center with a small coil diameter comes into contact with the rear end portion of the joint member 44 as shown in FIG. 9. Thereby, the inertia force of the conical coil spring 45 is transmitted to the chuck 7 that holds the writing core via the joint member 44, and the writing core is drawn out by moving the chuck 7 forward.
A more detailed configuration of the conical coil spring 45 used in this embodiment will be described later with reference to FIG.

  In the second embodiment, a swing-out mechanical pencil is formed by the action of the conical coil spring 45 functioning as the weight body described above, and the knock cover 35 is knocked in the axial direction. The chuck 7 can be advanced through the case 4. As a result, the lead can be drawn out as in the first embodiment.

  Further, in the second embodiment, a core lock mechanism 48 is disposed in the knock bar 32. The lead lock mechanism 48 performs a deep knocking operation (pushing the knock cover 35 beyond the above-described lead) so that the rotor 49 moves in the axial direction and rotates by a predetermined amount. Acts to be locked in the pushed-in state.

  When the knock cover 35 is knocked again in this locked state, the rotor 49 rotates again by a predetermined amount, so that the pushing state of the knock bar 32 is released and the original state is restored. The basic principle of the core locking mechanism 48 is called a so-called Kern knock mechanism and is often used in knock type ballpoint pens.

  Therefore, the lead case 4 and the chuck 7 are held in the advanced state by setting the lead lock mechanism 48 to the locked state. Thereby, even if the above-mentioned conical coil spring 45 as a weight body moves forward, it is possible to prevent the writing core from being drawn out by its inertial force.

FIG. 10 is an enlarged view of the conical coil spring 45 used in the second embodiment. In the present invention, the “conical coil spring” refers to a “conical coil spring” as defined in JIS B 0103-2012 classification 3242.
In the conical coil spring 45 shown in FIG. 10, the coil diameter is sequentially expanded using a wire rod 45 </ b> A having a circular cross section, and is wound spirally. Therefore, the conical coil spring 45 can secure the overall weight while forming the axial length small.

The conical coil spring 45 is loaded so that the central through hole 45a is inserted into the core case 4 and can be slid in the axial direction, as already described with reference to FIG.
In addition, as already described, the conical coil spring 45 is loaded such that one end portion 45 b protruding toward the shaft center side with a small coil diameter comes into contact with the rear end portion of the joint member 44.
As a result, the inertial force accompanying the forward movement of the conical coil spring 45 acts to effectively push the chuck 7 through the joint member 44.

Moreover, as for the said conical coil spring 45 utilized in this embodiment, it is desirable for the clearance gap 45c to be formed between each coil adjacent to an axial direction (sliding direction).
With this configuration, the conical coil spring 45 can be compressed in the sliding direction and can have an appropriate spring effect in the sliding direction, so that the impact caused by the inertia force of the conical coil spring 45 can be effectively reduced. it can. Therefore, this type of swing-out mechanical pencil can sufficiently exhibit the effect as a countermeasure against breakage of the core.

  According to the second embodiment of the mechanical pencil according to the present invention described above, since the conical coil spring is used as the weight body for moving the chuck for holding the writing core forward by inertia force, the axial direction as the weight body is used. The weight can be ensured while the length of the sheet is formed to be small. Therefore, this type of swing-out mechanical pencil can provide the functions and effects described in the above-mentioned column of the effect of the invention, such as being able to exhibit an ideal function.

  In the first embodiment provided with the rotary drive mechanism described above, a bamboo shoot spring is used as the weight body, and in the second embodiment, a conical coil spring is used as the weight body. Even if these weight bodies are replaced, the same effects can be obtained.

1 shaft cylinder 1A front shaft 1B rear shaft 4 core case 4A first core case 4B second core case 5 connecting member 7 chuck 8 fastener 9 slider 11 tip pipe 13 holding chuck 14 chuck spring 16 bamboo child spring (heavy body)
16A Metal base material 16a Through hole 16b Protruding end 16c Clearance 21 Rotation drive mechanism 22 Holder member 23 Rotating cam 23a Upper cam 23b Lower cam 24 Cushion member 25 Sliding member (torque canceller)
31 clip support 32 knock bar 33 shaft spring 34 eraser 35 knock cover 41 retaining ring 42 covering rubber 44 joint member 45 conical coil spring (heavy body)
45A Wire 45a Through hole 45b Protruding end 45c Clearance 46 Inner retaining ring 48 Core lock mechanism 49 Rotor

Claims (6)

A weight body is slidably loaded between the shaft cylinder and a core case that houses a spare writing core, and the chuck that grips the writing core is moved forward by the inertial force of the weight body generated by shaking the shaft cylinder. Let the pencil lead out the writing core,
A swing-out mechanical pencil using a bamboo shoot spring or a conical coil spring as the weight body.   The bamboo shoot spring is formed by using a rectangular base material to gradually increase the diameter of the long side and spirally winding it, and forming a gap between the base materials in the direction perpendicular to the sliding direction. The swing-out mechanical pencil according to claim 1, which is configured to be compressible in the sliding direction.   The conical coil spring is configured such that a coil diameter is sequentially expanded using a wire and spirally wound, and a gap is formed between coils adjacent to the slide direction so as to be compressible in the slide direction. The swing-out mechanical pencil according to claim 1, wherein   3. The end portion of the bamboo shoot spring that protrudes toward the axial center side with a small helical diameter is loaded in the shaft cylinder toward the front side where the chuck is disposed. A swing-out mechanical pencil.   The end portion of the conical coil spring that protrudes toward the axial center with a small coil diameter is loaded in the shaft cylinder toward the front side where the chuck is disposed. The swing-out mechanical pencil described.   A rotation drive mechanism for rotating the rotation cam based on a writing pressure received by the writing core is further provided, and the rotation movement of the rotation cam is transmitted to the writing core. The swing-out mechanical pencil according to any one of claims 1 to 5.

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