JP7336968B2 - writing instrument - Google Patents

Description

The present invention relates to writing instruments.

2. Description of the Related Art Conventionally, there has been known a rotary multi-core writing instrument in which one core out of a plurality of cores is projected and retracted from an opening at the front end of the front cylinder by relatively rotating a front cylinder and a rear cylinder that constitute a barrel. (for example, Patent Document 1, Patent Document 2, or Patent Document 3). In such a multi-core writing instrument, a cylindrical rotating cam that rotates together with the rear cylinder is provided inside the rear cylinder. The rotating cam is formed with a cam surface that is convex forward. When the rotating cam is rotated together with the rear cylinder, the rear end of the slide piece holding the core slides in the front-rear direction along the guide groove of the intermediate piece while contacting the cam surface of the rotating cam. The rear end portion of the slide piece enters the front end portion of the cam surface, thereby maintaining the state in which the core protrudes and retracts from the opening of the front cylinder. When the rotating cam is further rotated together with the rear barrel from this state, the rear end of the slide piece is disengaged from the front end of the cam surface and moves rearward along the guide groove of the middle piece. It is pulled back inside the front barrel.

JP 2012-61605 A Japanese Utility Model Publication No. 4-42153 Japanese Utility Model Publication No. 56-55021

A user who uses a writing instrument as described above can make one core out of a plurality of cores protrude and disappear from the opening of the front cylinder by rotating the front cylinder and the rear cylinder. However, when the user wants to make a desired core (for example, a frequently used core) appear and disappear from among a plurality of cores, it is necessary to perform a rotating operation until the desired core appears and disappears. It is necessary to visually confirm whether or not the core core that appears is the desired core core. As described above, it takes a lot of time and effort to make the desired core appear and retract, and it is not possible to immediately make the desired core appear and retract to set the writing state, so there is a problem that the time and effort is troublesome. Therefore, there is room for improvement in operability when a desired center core is projected and retracted from among a plurality of core cores.

By the way, when it is attempted to provide a conventional rotating retractable writing instrument (see FIG. 14(a)) with a function of easily retracting a desired core out of a plurality of cores housed in a barrel, it is difficult to obtain the desired core. Since a force to push the core forward is required, for example, as shown in FIG. 15, a configuration can be considered in which the rotating cam 102 is strongly urged forward (R2) of the barrel. However, simply adopting a configuration that strongly urges the rotating cam 102 forward would cause the knocking operation of the mechanical pencil center core, which is one of the cores, during the rotation of the rear cylinder with respect to the front cylinder. The slide protrusion 102a of the rotating cam 102 may get caught in the groove 101a (see FIGS. 14(b) and 15), and a problem may arise in that the rotating operation for retracting the center core cannot be properly performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in a writing instrument having a structure in which a predetermined biasing force is applied to a rotating cam in front of a barrel, the barrel can be rotated smoothly. The purpose is to provide a configuration that can

A writing instrument according to an embodiment of the present invention includes a barrel having an axis extending from a front end to a rear end and having an opening formed at the front end, and a core disposed inside the barrel and capable of retracting out of the opening. and a first retracting mechanism for retracting the core from the opening. The first retractable mechanism includes a core holder that holds the core, a slide piece that is attached to the rear of the core holder and includes a first projection projecting rearward, and a slide piece that is mounted rearward of the core. a first elastic member that biases the slide piece against the axial direction; a middle piece that engages with the shaft cylinder and holds the core; a rotatable cam biased forward by a second elastic member having a higher biasing force than the first elastic member. The rotating cam includes a cylindrical cam case and a cam portion that is separate from the cam case and is slidable in the axial direction with respect to the cam case. A second protrusion that contacts the first protrusion of the slide piece and a recess that abuts on the first protrusion of the slide piece are provided.

In this writing instrument, the rotary cam, which has conventionally been composed of a single component, is composed of a cam case and a cam portion which is separate from the cam case and is slidable in the axial direction with respect to the cam case. . Since the cam case rotatable with respect to the middle piece and the cam portion that moves along the axial direction are separately provided in this manner, the groove of the middle piece and the sliding portion that passes through the groove are not required. . Therefore, according to this writing instrument, even if a predetermined urging force is applied to the rotating cam toward the front of the barrel by the second elastic member or the like, the urging force prevents the rotation of the barrel. Therefore, the rotation of the barrel can be performed smoothly. It should be noted that this configuration can be applied to a writing instrument that employs "a configuration in which a desired core out of a plurality of cores can be easily retracted" described in the embodiment described later, but other configurations are possible. It can be applied to writing instruments.

In the writing instrument described above, it is preferable that the second projection and the recess of the cam portion are provided on the inner peripheral surface of the cam portion. Moreover, it is preferable that the cam portion is slidable along the inner peripheral surface of the cam case. According to these configurations, the movement of the slide piece along the axial direction by the cam portion can be made smoother, and the core can be easily protruded and retracted.

In the writing instrument described above, the barrel includes a front barrel having an opening and a rear barrel rotatably connected to the front barrel. are provided in plurality, and the first retracting mechanism may retract one of the plurality of cores out of the opening according to the rotation angle between the front cylinder and the rear cylinder. According to this rotating retractable writing instrument, one core can be retracted by rotating the front barrel and the rear cylinder, so the retracting operation of the core in the writing instrument is facilitated.

The above writing instrument has a knock portion that is slidable in the axial direction with respect to the front barrel, and when the knock portion is pushed down in the axial direction, a specific center core among the plurality of core cores is engaged. A second retracting mechanism for retracting to the outside from the opening may be further provided. In this writing instrument, when the front and rear barrels are rotated, one of the plurality of cores emerges and disappears from the opening according to the rotation angle between the front and rear barrels. On the other hand, when the knock portion is pushed down, a specific center core out of the plurality of cores emerges and disappears from the opening. That is, in this writing instrument, not only can one core be retracted by rotating the front barrel and the rear cylinder, but also a specific core can be retracted by pushing down the knock portion (knocking operation). Therefore, when the user wants to make a specific center core (desired core) out of a plurality of cores appear and disappear from the opening, the user only needs to perform a knocking operation, and there is no need to rotate the front cylinder and the rear cylinder. Become. Further, since the desired core is projected and retracted from the opening by performing the knocking operation, it is unnecessary to confirm whether or not the retracted core is the desired core. Therefore, according to this writing utensil, it is possible to save the trouble of moving a desired core out of the plurality of cores into and out of the opening. can. In other words, a desired center core out of the plurality of cores can be easily protruded and retracted from the opening.

In the above writing instrument, the mechanical pencil lead may be extended from the mechanical pencil core, which is the core, by moving the cam portion forward in the axial direction with respect to the cam case.

ADVANTAGE OF THE INVENTION According to the present invention, in a writing instrument having a configuration in which a predetermined biasing force is applied to a rotating cam toward the front of a barrel, it is possible to provide a configuration that enables the rotation of the barrel to be performed smoothly. can.

FIG. 1 is a perspective view showing the appearance of a writing instrument according to one embodiment of the present invention. 2 is an exploded perspective view showing the writing instrument of FIG. 1. FIG. 3 is a cross-sectional view showing the writing instrument of FIG. 1. FIG. FIG. 4(a) is a plan view showing the middle piece. FIG. 4(b) is a sectional view taken along line IVb--IVb of FIG. 4(a). FIG. 5(a) is a plan view showing a rotating cam. FIG. 5(b) is a cross-sectional view taken along line Vb-Vb of FIG. 5(a). FIG. 6 is a perspective view for explaining a mechanism for causing the core to protrude and retract from the opening by rotation of the rotating cam. FIG. 7(a) is a plan view showing the pusher. FIG. 7(b) is a cross-sectional view taken along line VIIb--VIIb of FIG. 7(a). FIG. 8(a) is a plan view showing the state of the presser and the rotating cam before the knock portion is pushed down. FIG. 8(b) is a plan view showing the state of the pusher and the rotating cam when the knock portion is pushed down. FIG. 9(a) is a plan view showing a support member. FIG. 9(b) is a cross-sectional view taken along line IXb--IXb of FIG. 9(a). FIG. 10(a) is an enlarged cross-sectional view of the vicinity of the support member before the knock portion is pushed down. FIG. 10(b) is a cross-sectional view enlarging the vicinity of the support member when the knock portion is pushed down. FIG. 11(a) is a cross-sectional view showing the state of the writing instrument before the knock portion is pushed down. FIG. 11(b) is a cross-sectional view showing the state of the writing instrument when the knock portion is pushed down. FIG. 12(a) is a cross-sectional view showing the state of the writing instrument when the knock portion is further pushed down from the state shown in FIG. 11(b). FIG. 12(b) is a cross-sectional view showing the state of the writing instrument when the knock portion returns to its original position from the state shown in FIG. 12(a). FIG. 13(a) is a partial view showing a state in which the cam case and the cam portion according to the present embodiment are in contact when a predetermined biasing force is applied to the rotating cam toward the front of the barrel. FIG. 13B is a partially transparent plan view showing a state in which the cam case and the cam portion are separated from each other. FIG. 14(a) is a diagram showing an example of a conventional rotating retractable writing instrument, and FIG. 14(b) is a partially enlarged view thereof. FIG. 15 is a diagram for explaining a problem in the conventional rotating retractable writing instrument shown in FIG. 14 when an urging force is applied toward the front.

Hereinafter, a writing instrument according to an embodiment of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. Further, in the following description, "axis" means a center line extending in the front-rear direction of the barrel, and "axial direction" means a direction along the axis (front-rear direction). "Radial" means the direction perpendicular to the axis, and "circumferential/rotational" means the direction along the ring about the axis. "Front/front" means one side in the axial direction and the tip side of the writing instrument, and "rear/rear" means the other side in the axial direction and the rear end side opposite to the tip direction of the writing instrument. means.

FIG. 1 is a perspective view showing the appearance of a writing instrument 1 according to this embodiment. FIG. 2 is an exploded perspective view showing the writing instrument 1. FIG. FIG. 3 is a cross-sectional view showing the writing instrument 1. FIG. As shown in FIGS. 1 to 3, the writing instrument 1 includes a barrel 10 having a front barrel 11 and a rear barrel 12 rotatably connected to the front barrel 11; A core 20 is provided. Moreover, as shown in FIG. 3, the writing instrument 1 is configured such that one core 20 out of the plurality of cores 20 protrudes and retracts outside from the front end of the barrel 10 according to the rotation of the front cylinder 11 and the rear cylinder 12 . 1 retractable mechanism M1, and a second retractable mechanism M2 for retracting a specific core out of the plurality of cores 20 from the front end of the barrel 10 by pushing down the knock portion 100 (knocking operation). there is

Since the writing instrument 1 is provided with the first retraction mechanism M1, one core core 20 out of the plurality of core cores 20 can be retracted by rotating (rotating operation) the front cylinder 11 and the rear cylinder 12 . Moreover, the writing instrument 1 can make a specific center core among the plurality of core cores 20 appear and retract by knocking operation by providing the second retraction mechanism M2. In this embodiment, the writing instrument 1 is configured such that the second retractable mechanism M2 uses the first retractable mechanism M1 to retract a specific core. Specifically, the second retractable mechanism M2 regulates the rotation angle between the front cylinder 11 and the rear cylinder 12 to a specific rotation angle, and the first retraction mechanism M1 adjusts the specific core according to the specific rotation angle. Make it haunt. However, the second retractable mechanism M2 may not use the first retractable mechanism M1, and may retract a specific center core by a mechanism different from the first retractable mechanism M1.

The shaft tube 10 has a cylindrical shape extending along the axial direction D, and is made of, for example, a resin material. The front cylinder 11 constitutes the front portion of the barrel tube 10 , and the rear cylinder 12 constitutes the rear portion of the barrel barrel 10 . The front cylinder 11 includes a front cylinder 13 including the front end of the front cylinder 11 , a middle cylinder 14 to which the front cylinder 13 is attached, and a display cover 15 that houses the middle cylinder 14 . The front tube 13 has a cylindrical shape that tapers toward the front. The front end of the tip tube 13 is formed with an opening 13a through which the tip (pen tip) of the core 20 can be retracted.

As shown in FIGS. 2 and 3, the middle cylinder 14 has a stepped cylindrical shape. It's getting smaller. A front portion 14 a of the middle cylinder 14 is detachably engaged with the front cylinder 13 . Specifically, the front tube 13 is removed from the middle tube 14 by screwing together a male screw formed on the outer peripheral surface of the front portion 14 a and a female screw formed on the inner peripheral surface of the rear portion of the front tube 13 . It is possible. When replacing the core 20 with an unused core, the core 20 can be easily replaced by removing the front tube 13 from the middle tube 14 .

The display cover 15 has a cylindrical shape that covers the outer peripheral surfaces of the central portion 14 c and the rear portion 14 b of the middle tube 14 . The inner peripheral surface of the display cover 15 is approximately the same as the outer diameter of the central portion 14c of the middle cylinder 14, and is engaged with the outer peripheral surface of the central portion 14c so as to be non-rotatable and non-movable in the axial direction D. . The outer peripheral surface of the display cover 15 is exposed to the outside of the writing instrument 1 and can be visually recognized from the outside. A mark indicating the type of core 20 is printed on the outer peripheral surface of the display cover 15, for example. A user of the writing instrument 1 can distinguish the type of core 20 to appear and disappear by checking the mark on the display cover 15 .

The rear cylinder 12 is connected to the front cylinder 11 so as to be rotatable and movable in the axial direction D. As shown in FIG. The outer diameter of the rear cylinder 12 is smaller than the inner diameter of the display cover 15 , and the front portion 12 a of the rear cylinder 12 is housed inside the display cover 15 . A front portion 12 a of the rear cylinder 12 is sandwiched between the inner peripheral surface of the display cover 15 and the outer peripheral surface of the middle cylinder 14 . As the front portion 12a of the rear cylinder 12 slides along the inner peripheral surface of the display cover 15 and the outer peripheral surface of the middle cylinder 14, the rear cylinder 12 is rotatable relative to the front cylinder 11 and movable in the axial direction D. It's becoming The rear cylinder 12 is formed with a slit 12b extending along the axial direction D from the front end of the front portion 12a. A knock portion 90 for a mechanical pencil, which will be described later, is inserted into the slit 12b. An annular protrusion 12c (see FIG. 3) is formed on the rear inner peripheral surface of the rear cylinder 12 and protrudes radially inward from the inner peripheral surface and extends in the circumferential direction.

As shown in FIGS. 2 and 3, the plurality of cores 20 includes, for example, two ballpoint pen cores 20a and 20b and a mechanical pencil core 20c. For example, core 20a is a core with red ink, and core 20b is a core with black ink. The cores 20a, 20b, and 20c are arranged side by side at equal intervals along the circumferential direction inside the front cylinder 11, for example. Note that the plurality of cores 20 are not limited to the cores 20a, 20b, and 20c, and may include cores of a different type from the cores 20a, 20b, and 20c. Moreover, the number of the cores 20 may be two or more, and is not limited to three, and may be four or more. In the following description, the cores 20a, 20b, and 20c are collectively referred to as the cores 20 when there is no need to distinguish between the cores 20a, 20b, and 20c.

A core holder 21 is provided behind the core 20 . The core holder 21 has a cylindrical shape with the axial direction D as the central axis direction, and detachably holds the rear end portion of the core 20 . A slide piece 22 is provided behind the core holder 21 . The slide piece 22 has a cylindrical shape with the axial direction D as the central axis direction, and the core holder 21 is inserted inside the front portion of the slide piece 22 . The slide piece 22 is engaged with the rear end portion of the core holder 21 so as to be rotatable and immovable in the axial direction D. As shown in FIG. A radial inner peripheral surface of the slide piece 22 serves as a sliding portion that slides along a guide groove 33a (see FIG. 3) of the middle piece 30, which will be described later. A protrusion 22a (first protrusion) is provided on the radially outer peripheral surface of the slide piece 22 and protrudes radially outwardly from the outer peripheral surface. The projection 22a has a triangular shape in which the width in the circumferential direction gradually narrows toward the rear when viewed from the projection direction of the projection 22a.

The middle piece 30 is inserted inside the barrel 10 and holds the middle core 20 . The middle piece 30 extends in the axial direction D from the inside of the middle cylinder 14 of the front cylinder 11 to the inside of the rear cylinder 12, as shown in FIG. The middle piece 30 is non-rotatably engaged with the middle cylinder 14 of the front cylinder 11 and is rotatable with respect to the rear cylinder 12 . Further, the intermediate piece 30 is movable in the axial direction D with respect to the front cylinder 11 together with the rear cylinder 12 .

4A is a plan view showing the middle piece 30. FIG. FIG. 4(b) is a sectional view taken along line IVb--IVb of FIG. 4(a). As shown in FIGS. 4(a) and 4(b), the intermediate piece 30 includes a front tubular portion 31 forming the front portion of the intermediate piece 30 and a rear tubular portion 32 forming the rear portion of the intermediate piece 30 ( and a rod-shaped portion 33 that connects the front tubular portion 31 and the rear tubular portion 32 in the axial direction D. The front cylindrical portion 31 has a bottomed cylindrical shape with an opening forward, and accommodates the rear end portion of the core 20 and the front end portion of the core holder 21 (see FIG. 3). A plurality of through holes 31a are formed in the bottom portion of the front cylindrical portion 31 so as to extend through the bottom portion in the axial direction D. As shown in FIG. Each through hole 31a is arranged to correspond to each core holder 21, and each core holder 21 is inserted through each through hole 31a.

The rod-shaped portion 33 extends rearward in the axial direction D from the bottom portion of the front cylindrical portion 31 . The outer diameter of the rod-shaped portion 33 is smaller than the outer diameter of the front cylindrical portion 31, and the outer peripheral surface of the rod-shaped portion 33 is formed with a plurality of guide grooves 33a communicating with the plurality of through holes 31a. Each guide hole extends linearly rearward from each through hole 31a. As shown in FIG. 3, the core holder 21 and the slide piece 22 are accommodated inside the guide groove 33a. The outer peripheral surface of the slide piece 22 slides in the axial direction D on the inner surface of the guide groove 33a. A spring S1 (first elastic member) is wound around the core holder 21 inside the guide groove 33a. The front end of the spring S1 contacts the stepped portion between the front cylindrical portion 31 and the bar portion 33, and the rear end of the spring S1 contacts the front end of the slide piece 22. As shown in FIG. The slide piece 22 is urged rearward against the front cylindrical portion 31 of the intermediate piece 30 by the biasing force of the spring S1.

The rear tubular portion 32 protrudes in a cylindrical shape from the rear end of the rod-shaped portion 33 . The outer diameter of the rear tubular portion 32 is approximately the same as the outer diameter of the rod-shaped portion 33 . As shown in FIGS. 4(a) and 4(b), a pair of elastic projections 32a are formed on the front portion of the rear tubular portion 32 at a pair of positions facing each other in the radial direction. The elastic protrusion 32 a protrudes radially outward from the outer peripheral surface of the rear cylindrical portion 32 . As shown in FIG. 4( a ), a U-shaped notch that communicates the inside and outside of the rear tubular portion 32 is formed around the elastic protrusion 32 a of the rear tubular portion 32 . Therefore, the elastic protrusion 32a has elasticity in the radial direction. The cutouts are a pair of slits 32b formed on both sides of the elastic projection 32a of the rear tubular portion 32 in the circumferential direction and extending in the axial direction D, and the elastic projection 32a of the rear tubular portion 32. and a slit 32c extending in the circumferential direction continuously from the pair of slits 32b.

The wall portion of the rear tubular portion 32 surrounded by the notch forms an arm having flexibility in the radial direction. Therefore, the elastic projection 32a arranged on the outer surface of the front end of the arm has a biasing force in the radial direction. For this reason, the elastic protrusion 32a enters the inside of the rear cylindrical portion 32 when receiving an external force radially inward, and returns to its original position when the external force is released. In the original position, the elastic protrusion 32a faces the rear end of the cam case 41 of the rotating cam 40, which will be described later, in the axial direction D (see FIGS. 10(a) and 10(b)). The rear portion of the rear tubular portion 32 has a pair of arms 32d that are bifurcated from the rear end of the front portion of the rear tubular portion 32 and face each other in the radial direction. The pair of arms 32d are formed by a pair of slits 32e extending forward from the rear end of the rear tubular portion 32 by a predetermined length. A pair of slits 32e are formed at a pair of positions facing each other in a radial direction perpendicular to the facing direction of the pair of arms 32d.

Refer to FIG. 3 again. As shown in FIG. 3, the rotating cam 40 is housed inside the rear cylinder 12 and engages with the rear cylinder 12 so as to be synchronously rotatable. The rotating cam 40 has a cylindrical shape with the axial direction D as the central axis direction, and the rod-shaped portion 33 of the intermediate piece 30 is inserted through the rotating cam 40 . The rotating cam 40 is rotatable with respect to the bar-shaped portion 33 . Therefore, the rotating cam 40 rotates together with the rear cylinder 12 with respect to the intermediate piece 30 . Since the middle piece 30 is non-rotatably engaged with the front cylinder 11 as described above, the rotation angle between the front cylinder 11 and the rear cylinder 12 is determined by the rotation angle between the middle piece 30 and the rotating cam 40. can be regulated.

The front end of the rotating cam 40 abuts the rear end (edge) of the rear portion 14b of the middle cylinder 14 in the axial direction D. As shown in FIG. This restricts the forward movement of the rotating cam 40 with respect to the front cylinder 11 . A spring s, which will be described later, is provided behind the rotating cam 40, and the rotating cam 40 is biased forward by the biasing force of a spring S2 (second elastic member). In this manner, the rotation cam 40 is held between the rear end of the rear portion 14b and the spring S2, so that the position of the rotation cam 40 in the axial direction D with respect to the front cylinder 11 is maintained.

FIG. 5(a) is a plan view showing the rotating cam 40. FIG. FIG. 5(b) is a cross-sectional view taken along line Vb-Vb of FIG. 5(a). As shown in FIGS. 5(a) and 5(b), the rotating cam 40 includes a stepped cylindrical cam case 41 whose central axis direction is the axial direction D, and a curved plate-like cam case 41 that is separate from the cam case 41. and a cam portion 42 . The cam case 41 includes a front tubular portion 43 forming a front portion of the cam case 41 and a rear tubular portion 44 forming a rear portion of the cam case 41 . The outer diameter of the rear tubular portion 44 is smaller than the outer diameter of the front tubular portion 43 , and a stepped portion 45 is formed at the boundary between the front tubular portion 43 and the rear tubular portion 44 .

The cam portion 42 is housed inside the front tubular portion 43 and curves along the inner peripheral surface of the front tubular portion 43 . The cam portion 42 is engaged with the inner peripheral surface of the front cylindrical portion 43 so as not to be relatively rotatable. Further, the cam portion 42 can slide in the axial direction D with respect to the front tubular portion 43 by the outer peripheral surface of the cam portion 42 sliding on the inner peripheral surface of the front tubular portion 43 in the axial direction D. The rear end of the cam portion 42 contacts the inner peripheral surface of the front tubular portion 43 (specifically, the stepped surface between the front tubular portion 43 and the rear tubular portion 44 inside the cam case 41) in the axial direction D. there is This restricts the rearward movement of the cam portion 42 with respect to the front tubular portion 43 . The front end of the cam portion 42 protrudes forward from the front end of the front tubular portion 43 .

On the inner surface of the cam portion 42, as shown in FIG. 5B, a protrusion 42a (second protrusion) is formed that protrudes radially inward from the inner surface. The projection 42a has a triangular shape in which the width in the circumferential direction gradually narrows toward the front when viewed from the projection direction of the projection 42a. A recess 42b that is slightly recessed rearward is formed at the front end (tip) of the projection 42a. On the outer surface of the cam portion 42 is attached a mechanical pencil knock portion 90 for drawing out the core 20 for the mechanical pencil (see FIG. 3). A knock portion 90 for a mechanical pencil protrudes to the outside of the front tubular portion 43 through a slit formed in the front tubular portion 43 and is exposed to the outside of the writing instrument 1 . The mechanical pencil knock portion 90 is slidable forward together with the cam portion 42 with respect to the front cylindrical portion 43 . By pushing down the knock part 90 for the mechanical pencil in a state where the core 20c for the mechanical pencil protrudes from the opening 13a, the sharp core of the core 20c can be drawn out.

The rear tubular portion 44 includes a cylindrical main body portion 44a and a cam receiving portion 44b formed on the outer peripheral surface of the main body portion 44a. The cam receiving portion 44b is provided to receive a cam portion 52 (see FIGS. 3 and 6) of the pusher 50, which will be described later. The cam receiving portion 44b is formed on the outer peripheral surface of the body portion 44a. The cam receiving portion 44b protrudes rearward from the stepped portion 45 in a claw shape, and surrounds the outer peripheral surface of the main body portion 44a in the circumferential direction. Specifically, the cam receiving portion 44b has a shape obtained by cutting a cylindrical shape extending in the axial direction D along a plane inclined from a vertical plane of the axial direction D. As shown in FIG. The cam receiving portion 44b includes a cam receiving surface 44c having a cross-sectional shape cut along the plane. The cam receiving surface 44c is formed at the rear end of the cam receiving portion 44b and faces rearward in the axial direction D. As shown in FIG. The cam receiving surface 44c faces the cam surface 52a of the cam portion 52 in the axial direction D (see FIG. 3).

The slide piece 22 , the middle piece 30 , and the rotary cam 40 move one of the plurality of cores 20 out of the front end of the shaft tube 10 so as to protrude and retract according to the rotation angle between the front tube 11 and the rear tube 12 . A first retraction mechanism M1 is configured to allow the The rotating cam 40 converts the rotation of the front cylinder 11 and the rear cylinder 12 into the movement of the core 20 in the axial direction D, thereby moving the core 20 according to the rotation angle of the front cylinder 11 and the rear cylinder 12. It is caused to appear and disappear outside through the opening 13a. Specifically, when the rear cylinder 12 rotates with respect to the front cylinder 11 , the rotating cam 40 rotates with respect to the middle piece 30 , and the cam portion 42 of the rotating cam 40 rotates the rotating cam 40 in the axial direction D of the core 20 . Convert to move to . Here, referring to FIG. 6, a mechanism for causing the center core 20 to protrude and retract from the opening 13a by the rotation of the rotary cam 40 will be described.

FIG. 6 is a perspective view for explaining a mechanism for causing the center core 20 to protrude and retract from the opening 13a by the rotation of the rotary cam 40. As shown in FIG. For convenience of explanation, FIG. 6 omits the barrel 10 and the knock portion 90 for the mechanical pencil. When the rotary cam 40 rotates with respect to the intermediate piece 30 , the protrusion 42 a of the cam portion 42 of the rotary cam 40 contacts the protrusion 22 a of the slide piece 22 . When the protrusion 42a of the cam portion 42 abuts the protrusion 22a of the slide piece 22, the protrusion 22a of the slide piece 22 receives force from the protrusion 42a of the cam portion 42, and moves toward the guide groove 33a (see FIG. 3). , in the axial direction D.

Then, as shown in FIG. 6, when the protrusion 22a of the slide piece 22 enters the recess 42b formed in the front end portion of the protrusion 42a of the cam portion 42, the core 20 attached to the slide piece 22 is opened. It will be in a state of appearing outside from 13a. When the rotating cam 40 is further rotated with respect to the middle piece 30 from this state, the projection 22a of the slide piece 22 is disengaged from the recess 42b of the cam portion 42, moves rearward along the guide groove 33a, and emerges from the opening 13a. The core 20 is pulled back inside the barrel 10 .

Therefore, the circumferential position of the recess 42b of the rotating cam 40 with respect to the middle piece 30 and the circumferential position of the protrusion 22a of the slide piece 22 with respect to the middle piece 30 (that is, the circumferential position of the core 20 with respect to the middle piece 30) ), the core 20 that appears and disappears from the opening 13a is switched. For example, when the circumferential position of the concave portion 42b coincides with the circumferential position of the core 20a, the core 20a appears and disappears from the opening 13a. The same applies to the cores 20b and 20c. That is, when the rotation angle of the concave portion 42b with respect to the middle piece 30 coincides with the rotation angle of the core 20 with respect to the middle piece 30, the core 20 appears and disappears from the opening 13a. In this manner, among the plurality of cores 20, the core 20 corresponding to the rotation angle between the core 30 and the rotating cam 40 (that is, the rotation angle between the front cylinder 11 and the rear cylinder 12) is positioned outside the opening 13a. to haunt.

Also, with reference to FIGS. 13 to 15, the difference between the configuration of the middle piece 30 and the rotating cam 40 of the writing instrument 1 according to the present embodiment and the configuration of the middle piece 101 and the rotating cam 102 of the conventional writing instrument T will be described. do. As shown in FIGS. 14(a) and 14(b), in the conventional writing instrument T, the rotary cam 102 is urged backward with a slightly weak force by the slide piece and the spring housed in the middle piece 101, and forward. There is no spring or the like for biasing. However, when it is attempted to provide the above-described second retracting mechanism M to the writing instrument T having the conventional configuration, as shown in FIG. When the rotary cam 102 is rotated, the slide projection 102a provided on the inner periphery of the rotary cam 102 is caught in the groove 101a of the middle piece 101 (see areas A1 and A2), hindering the rotation. put away. The slide projection 102a and the groove 101a function as guides for knocking when the core is for a mechanical pencil, and it is difficult to remove this function.

Therefore, in the writing instrument 1 according to the present embodiment, as shown in FIGS. A slidable cam portion 42 is included. The cam portion 42 is provided with a projection 42a that projects toward the projection 22a of the slide piece 22 and a recess 42b that contacts the projection 22a of the slide piece 22, and the projection 22a of the slide piece 22 is a recess. He is trying for the center core 20 to protrude outside from an opening by contact|abutting 42b. For this reason, in the writing instrument 1, even if a predetermined biasing force is applied from the spring S2 toward the front of the front barrel 11 to the rotating cam 40, the biasing force prevents the rotation of the barrel 10 from rotating. Since the cam 40 does not have it, the rear cylinder 12 can be smoothly rotated with respect to the front cylinder 11, and the rotary retractable writing instrument can sufficiently function. In addition, in this embodiment, the biasing force of the spring S2 is larger than the biasing force of the spring S1. Moreover, in the writing instrument 1 , the protrusion 42 a and the recess 42 b of the cam portion 42 are provided on the inner peripheral surface of the cam portion 42 , and the cam portion 42 is slidable along the inner peripheral surface of the cam case 41 . is. Therefore, the movement of the slide piece 22 by the cam portion 42 can be made smoother, and the core 20 can be easily protruded and retracted.

Again, refer to FIGS. 2 and 3. FIG. The middle piece 30 described above, the presser 50 fixed to the middle piece 30 behind the middle piece 20, the erasing member 60 provided behind the middle piece 30, and the erasing member provided at the rear end of the middle piece 30 A support member 70 that supports the member 60 and a cap 80 projecting rearward from the rear end of the barrel 10 and attached to the support member 70 so as to cover the erasing member 60 constitute the aforementioned knock portion 100 . Each component constituting the knock portion 100 is slidable in the axial direction D with respect to the front cylinder 11 . When the cap 80 is pushed forward by the user, the middle piece 30, the pusher 50, the erasing member 60, and the support member 70 are pushed forward accordingly. The knocking part 100 and the first retracting mechanism M1 constitute a second retracting mechanism M2 that retracts a specific center core out of the plurality of cores 20 to the outside from the front end of the barrel 10 by a knocking operation. That is, in the present embodiment, the second retractable mechanism M2 shares and utilizes the first retractable mechanism M1, and causes a specific central core corresponding to a specific rotation angle to appear and retract outside from the opening 13a.

The pusher 50 has a cylindrical shape with the axial direction D as the central axis direction, and the rear side cylindrical portion 32 of the middle piece 30 is inserted through the inside of the pusher 50 . The pusher 50 is engaged with the rear cylindrical portion 32 so as to be non-rotatable and non-movable in the axial direction D. As shown in FIG. Therefore, the pusher 50 is not rotatable with respect to the front cylinder 11 and is movable in the axial direction D with respect to the front cylinder 11 together with the middle piece 30 and the rear cylinder 12 .

FIG. 7(a) is a plan view showing the pusher 50. FIG. FIG. 7(b) is a cross-sectional view taken along line VIIb--VIIb of FIG. 7(a). As shown in FIGS. 7(a) and 7(b), the pusher 50 includes a cylindrical base portion 51 whose central axis direction is the axial direction D, and a claw-like cam protruding forward from the front end of the base portion 51. a portion 52; The inner peripheral surface 51a of the base portion 51 is a portion that engages with the rear tubular portion 32 so as to be non-rotatable and non-movable in the axial direction D. As shown in FIG. The outer diameter of the cam portion 52 is smaller than the outer diameter of the base portion 51 , and a stepped portion 53 is formed at the boundary between the cam portion 52 and the base portion 51 . The cam portion 52 has a shape obtained by cutting a cylindrical shape extending in the axial direction D along a plane inclined from a vertical plane in the axial direction D. As shown in FIG. The cam portion 52 includes a cam surface 52a having a cross-sectional shape cut along the plane. The surface shape of the cam surface 52a corresponds to the cam receiving surface 44c of the rotary cam 40, and is formed to be engageable with the cam receiving surface 44c in the rotational direction. The cam surface 52a is formed at the front end of the cam portion 52 and faces forward in the axial direction D. As shown in FIG. The cam surface 52a faces the cam receiving surface 44c in the axial direction D as described above.

As shown in FIGS. 3 and 6, a spring S2 is provided between the pusher 50 and the rotating cam 40. As shown in FIG. The front end of the spring S2 is in contact with the stepped portion 45 of the rotating cam 40 through a metallic ring R1, and the rear end of the spring S2 is in contact with the stepped portion of the pusher 50 through another metallic ring R2. 53. The rings R1 and R2 are springs between the rotating cam 40 and the presser 50 that rotate relative to each other when the core is retracted by the first retracting mechanism M1 (or the first retracting mechanism M1 and the second retracting mechanism M2). S2 is provided to prevent the stepped portion 45 of the rotating cam 40 and the stepped portion 53 of the pressing member 50 from being damaged due to the rotational movement of the rotating cam 40 and the pressing member 50 and the sliding along the axial direction D. It is The cam portion 52 of the pusher 50 and the cam receiving portion 44b are arranged inside the spring S2. The rotating cam 40 is urged forward with respect to the pusher 50 by the urging force of the spring S2. As described above, the front end of the rotating cam 40 abuts the rear end of the rear portion 14b of the middle cylinder 14 in the axial direction D, so that the rotating cam 40 moves toward the rear end of the rear portion 14b (that is, It is pressed against the front barrel 11). Thereby, the position of the rotary cam 40 in the axial direction D relative to the front cylinder 11 is maintained. Further, the spring S2 restores the position of the knock part 100 to its original position (the position before being pushed down) by urging the pusher 50 rearward when the knock part 100 is pushed down.

The cam portion 52 of the pusher 50 and the cam receiving portion 44b of the rotating cam 40 are arranged to rotate between the intermediate piece 30 and the rotating cam 40, that is, between the front cylinder 11 and the rear cylinder 12 when the knock portion 100 is pushed down. regulates the rotation angle of FIG. 8(a) is a plan view showing the state of the pusher 50 and the rotating cam 40 before the knock portion 100 is pushed down. FIG. 8(b) is a plan view showing the state of the presser and the rotating cam when the knock portion 100 is pushed down. 8(a) and 8(b) omit the shaft cylinder 10 and the springs S2 and S3 for convenience of explanation. When the knock portion 100 is pushed down from the state shown in FIG. When the pusher 50 moves further forward from this state, the force received by the cam receiving surface 44c from the cam surface 52a causes the cam receiving surface 44c to rotate relative to the cam surface 52a and engage with the cam surface 52a in the rotational direction. . In this manner, the cam receiving surface 44c is engaged with the cam surface 52a in the rotational direction, so that the rotation angle of the rotary cam 40 with respect to the presser 50 is restricted to a specific rotation angle.

The rotation angle of the rotary cam 40 with respect to the pusher 50 can be defined by the rotation angle of the rotation cam 40 with respect to the intermediate piece 30 to which the pusher 50 is fixed, that is, the rotation angle between the front cylinder 11 and the rear cylinder 12 . Therefore, by engaging the cam receiving surface 44c with the cam surface 52a in the rotational direction, the rotational angle between the front cylinder 11 and the rear cylinder 12 is regulated to a specific rotational angle, and the rotating cam 40 rotates the plurality of cores 20. Among them, a specific core corresponding to a specific rotation angle is caused to protrude outside from the opening 13a.

In this embodiment, the "specific rotation angle" is when the position of the recess 42b of the rotating cam 40 in the rotational direction with respect to the middle piece 30 coincides with the position of the core 20a, 20b or 20c in the rotational direction with respect to the middle piece 30. , the angle of rotation between the front cylinder 11 and the rear cylinder 12 . In the present embodiment, the "specific rotation angle" is the front cylinder 11 when the position of the concave portion 42b of the rotating cam 40 with respect to the middle piece 30 in the rotational direction coincides with the position of the core 20b with respect to the middle piece 30 in the rotational direction. and the rotation angle of the rear cylinder 12 is illustrated. The “specific rotation angle” can be set by adjusting the rotational position of the pusher 50 with respect to the middle piece 30 when the writing instrument 1 is manufactured. The "specific core" is any one of the cores 20a, 20b, or 20c at a position corresponding to the "specific rotation angle". In this embodiment, the "specific core" is the core 20b that is frequently used.

Therefore, in the present embodiment, when the knock portion 100 is pushed down, the core 20b among the plurality of cores 20 emerges and disappears from the opening 13a. It should be noted that the "specific center core" can be changed according to the user's intention. As described above, the core 20 is detachable from the core holder 21. Therefore, by replacing the core 20b at the position corresponding to the "specific rotation angle" with another core 20a or 20c, " "Specific core" can be set to the other core 20a or 20c. Therefore, the user can arbitrarily set a desired central core (a specific central core) that he/she wants to immediately appear and disappear from the opening 13a.

Again, refer to FIGS. 2 and 3. FIG. The erasing member 60 is a member for erasing handwriting with the writing instrument 1, and is, for example, an eraser. The erasing member 60 has, for example, a cylindrical shape. The support member 70 houses the front portion of the erasing member 60 . The support member 70 is inserted inside the rear end portion of the rear cylinder 12 . The cap 80 is detachably engaged with the support member 70 . By removing the cap 80 from the support member 70, the erasing member 60 is ready for use.

9A is a plan view showing the support member 70. FIG. FIG. 9(b) is a cross-sectional view taken along line IXb--IXb of FIG. 9(a). The support member 70 includes a holding portion 71 that holds the erasing member 60 and a support portion 72 that supports the holding portion 71 . The holding portion 71 has a columnar shape with the axial direction D as the central axis direction. A pair of insertion holes 71 a into which the pair of arms 32 d of the rear cylinder portion 32 of the intermediate piece 30 are inserted are formed in the front portion of the holding portion 71 . By fitting the pair of arms 32d into the pair of insertion holes 71a respectively, the holding portion 71 cannot rotate and move in the axial direction D with respect to the rear cylindrical portion 32 of the intermediate piece 30. As shown in FIG. A recessed portion 71 b into which the erasing member 60 is fitted is formed in the rear portion of the holding portion 71 .

The support portion 72 is configured separately from the holding portion 71 and is non-rotatable and movable in the axial direction D with respect to the holding portion 71 . The support portion 72 includes a body portion 72a that supports the holding portion 71, a rod-shaped portion 72b that projects forward from the front end of the body portion 72a, and a protrusion 72c that projects radially outward from the front end of the rod-shaped portion 72b. contains. The main body portion 72 a has a bottomed cylindrical shape that opens rearward and accommodates the holding portion 71 . The rearward movement of the support portion 72 with respect to the holding portion 71 is restricted by the bottom portion of the main body portion 72a coming into contact with the front end of the holding portion 71 in the axial direction D. As shown in FIG. A pair of through holes 72d extending in the axial direction D are formed in the bottom portion of the main body portion 72a. The pair of through holes 72d respectively correspond to the pair of insertion holes 71a. A pair of arms 32d of the rear cylindrical portion 32 of the intermediate piece 30 are inserted through the pair of through holes 72d. By inserting the pair of arms 32d into the pair of through holes 72d, respectively, the support portion 72 cannot rotate with respect to the middle piece 30. As shown in FIG. Further, since the through hole 72d is slidable in the axial direction D with respect to the arm 32d, the support portion 72 is slidable forward with respect to the holding portion 71. As shown in FIG.

A cap 80 is engaged with the rear portion of the body portion 72a. Specifically, a male screw formed on the outer peripheral surface of the rear portion of the main body portion 72a and a female screw formed on the inner peripheral surface of the front portion of the cap 80 are screwed together so that the cap 80 is attached to the main portion 72a. is detachably engaged with the An annular protrusion 72e is formed on the outer peripheral surface of the body portion 72a so as to protrude radially outward from the outer peripheral surface and extend in the circumferential direction.

As shown in FIG. 3, the annular protrusion 72e is non-rotatably engaged with the inner peripheral surface of the rear end portion of the rear cylinder 12, and faces the annular protrusion 12c of the rear cylinder 12 in the axial direction D. ing. A spring S3 is provided between the annular protrusion 72e and the annular protrusion 12c of the rear cylinder 12. As shown in FIG. Inside the spring S3, the rear cylindrical portion 32 of the intermediate piece 30 and the portion of the support portion 72 on the front side of the annular protrusion 72e are arranged. The front end of the spring S3 abuts the annular projection 12c of the rear cylinder 12, and the rear end of the spring S3 abuts the annular projection 72e of the body portion 72a. The support portion 72 is urged rearward with respect to the rear cylinder 12 by the urging force of the spring S3. The spring S3 restores the position of the knock portion 100 to its original position by urging the support portion 72 rearward when the knock portion 100 is pushed down.

The bar-shaped portion 72b protrudes forward from the central portion of the bottom portion of the body portion 72a. As shown in FIG. 3, the rod-shaped portion 72b is inserted inside the rear cylindrical portion 32 of the middle piece 30, and the outer diameter of the protrusion 72c is the same as or slightly smaller than the inner diameter of the rear cylindrical portion 32. It's becoming Therefore, when the projection 72c is located on the back side of the elastic projection 32a (see FIGS. 4A and 4B) of the rear tubular portion 32 (that is, when the projection 72c is projected from the elastic projection 32a in the axial direction D), 72c at the same position), even if the elastic protrusion 32a receives an external force and tries to enter the inside of the rear cylindrical portion 32, the elastic protrusion 32a abuts against the protrusion 72c, thereby Intrusion of the elastic protrusion 32a into the inner side of the cylindrical portion 32 is suppressed. On the other hand, the outer diameter of the rod-shaped portion 72b is smaller than the inner diameter of the rear tubular portion 32, and the radial gap between the rod-shaped portion 72b and the rear tubular portion 32 is defined by the elastic projection 32a. 32 is allowed.

It is designed so that the projection 72c is located on the back side of the elastic projection 32a of the rear tubular portion 32 when the knock portion 100 is in its original position before being pushed down. FIG. 10(a) is an enlarged cross-sectional view of the vicinity of the protrusion 72c before the knock portion 100 is pushed down. In the state shown in FIG. 10( a ), the elastic protrusion 32 a is in contact with the protrusion 72 c in the radial direction, so that the elastic protrusion 32 a is prevented from entering the inside of the rear tubular portion 32 . Therefore, in this state, even if the rotary cam 40 moves rearward against the biasing force of the spring S2 and comes into contact with the elastic protrusion 32a, the elastic protrusion 32a does not enter the rear cylindrical portion 32. Therefore, the retraction of the rotating cam 40 is restricted by the contact of the rotating cam 40 with the elastic protrusion 32a.

FIG. 10(b) is an enlarged cross-sectional view of the vicinity of the projecting portion 72c when the knock portion 100 is pushed down. When the cap 80 is pushed down by a knocking operation, the support portion 72 to which the cap 80 is attached slides forward with respect to the intermediate piece 30 . Accordingly, the projection 72c of the support portion 72 also slides forward with respect to the rear cylindrical portion 32 of the intermediate piece 30, so that the projection 72c is no longer positioned behind the elastic projection 32a. When the cap 80 is further pushed down from this state, the annular projection 12c of the rear cylinder 12 receives force from the annular projection 72e of the support portion 72 via the spring S3, whereby both the rear cylinder 12 and the intermediate piece 30 slide forward. Then, the elastic protrusion 32a of the intermediate piece 30 contacts the rear end of the cam case 41 of the rotary cam 40 in the axial direction D. As shown in FIG. At this time, since the projecting portion 72c is not positioned on the back side of the elastic projecting portion 32a, the elastic projecting portion 32a receives force from the rear end of the cam case 41 and enters the rear cylindrical portion 32 radially inward. As a result, the rear cylinder 12 and the intermediate piece 30 can be slid further forward, so that the push-down of the knock portion 100 is not hindered. In this manner, the elastic protrusion 32a and the protrusion 72c constitute a movement restricting portion R that restricts the retraction of the rotating cam 40 and allows the knock portion 100 to be pushed down.

Next, a description will be given of an operation when the specific center core 20b is projected and retracted from the opening 13a by a knocking operation. FIG. 11(a) is a cross-sectional view showing the state of the writing instrument 1 before the knock portion 100 is pushed down. FIG. 11(b) is a cross-sectional view showing the state of the writing instrument 1 when the knock portion 100 is pushed down. As shown in FIG. 11(a), before the knocking operation is performed, the core 20a for the red ball-point pen protrudes from the opening 13a. When the knock part 100 is pushed down from the state of the writing instrument 1 shown in FIG. 11(a), as shown in FIG. 72 are pushed forward against the biasing force of the spring S3.

At this time, as described above, the projecting portion 72c of the support portion 72 moves forward from the position on the back side of the elastic projecting portion 32a of the rear cylindrical portion 32 of the intermediate piece 30 in the axial direction D, and the elastic projecting portion 32a moves forward. The protrusion 72c is no longer positioned on the back side. Therefore, when the spring S3 is pushed down together with the support portion 72, the annular protrusion 12c of the rear cylinder 12 is pushed down by the spring S3. As a result, the rear cylinder 12, the middle piece 30, the pusher 50, the erasing member 60, and the support member 70 are integrally pushed forward. When the middle piece 30 is pushed forward and the elastic projection 32a of the middle piece 30 comes into contact with the rear end of the cam case 41 of the rotating cam 40, the elastic projection 32a receives an external force from the rear end of the cam case 41 and moves rearward. It enters the inside of the cylindrical portion 32 . As a result, the rear cylinder 12, the middle piece 30, the presser 50, the erasing member 60, and the support member 70 are further pushed forward. When the pusher 50 is pushed forward and reaches the rotating cam 40 , the cam surface 52 a of the pusher 50 contacts the cam receiving surface 44 c of the rotating cam 40 .

FIG. 12(a) is a sectional view showing the state of the writing instrument 1 when the knock portion 100 is further pushed down from the state shown in FIG. 11(b). FIG. 12(b) is a sectional view showing the state of the writing instrument 1 when the knock portion 100 returns to its original position from the state shown in FIG. 12(a). As shown in FIG. 12(a), when the cam surface 52a contacts the cam receiving surface 44c, the rotating cam 40 rotates with respect to the pusher 50 due to the force that the cam receiving surface 44c receives from the cam surface 52a (see FIG. 8). (a) and FIG. 8(b)). By engaging the cam surface 52a with the cam receiving surface 44c in the rotational direction, the rotation angle between the rotary cam 40 and the intermediate piece 30, that is, the rotation angle between the front cylinder 11 and the rear cylinder 12, is set to a specific rotation angle. Regulated.

As a result, as shown in FIG. 12(b), a specific center core 20b corresponding to a specific rotation angle among the plurality of core cores 20 appears and disappears from the opening 13a. At this time, as the middle piece 30 and the rotating cam 40 rotate according to the rotation of the front cylinder 11 and the rear cylinder 12, the rear end of the protrusion 22a of the slide piece 22 attached to the core 20b is It slides in the axial direction D along the guide groove 33a of the intermediate piece 30 while contacting the protrusion 42a of the cam portion 42 of the rotating cam 40. As shown in FIG. The protrusion 22a of the slide piece 22 enters the recess 42b formed at the front end of the protrusion 42a, so that the state in which the specific core 20b appears and disappears from the opening 13a of the front cylinder 11 is maintained. Then, the knock portion 100 returns to its original position due to the urging forces of the springs S2 and S3.

Next, effects obtained by the writing instrument 1 according to this embodiment will be described.

In the writing instrument 1 according to the present embodiment, when the front barrel 11 and the rear barrel 12 are rotated, one of the plurality of cores 20 is opened according to the rotation angle between the front barrel 11 and the rear barrel 12. Go out from 13a. On the other hand, when the knock part 100 is pushed down, a specific center core 20b among the plurality of cores 20 appears and disappears from the opening 13a. That is, in this writing instrument 1, not only can one central core 20 appear and retract by rotating the front barrel 11 and the rear barrel 12, but also a specific central core 20b can appear and retract by a knocking operation. Therefore, when the user wants to make a specific core 20b (desired core 20b) out of the plurality of cores 20 protrude from the opening 13a, the user can perform a knocking operation. rotation operation becomes unnecessary. Furthermore, since the desired center core 20b can be projected and retracted from the opening 13a by performing the knocking operation, it is unnecessary to confirm whether or not the retracted core 20 is the desired core 20b. Therefore, according to the writing instrument 1, it is possible to omit the trouble of moving the desired core 20b out of the plurality of cores 20 into and out of the opening 13a. state can be made. That is, the desired core 20b among the plurality of cores 20 can be easily protruded and retracted from the opening 13a.

In the writing instrument 1 according to this embodiment, the second retraction mechanism M2 regulates the rotation angle between the front cylinder 11 and the rear cylinder 12 to a specific rotation angle when the knock portion 100 is pushed forward in the axial direction D. Then, the first retracting mechanism M1 retracts the specific center core 20b according to the specific rotation angle from the opening 13a. Thus, when configuring the second retraction mechanism M2 using the first retraction mechanism M1, compared to the case of configuring the second retraction mechanism M2 using a mechanism different from the first retraction mechanism M1, The second retractable mechanism M2 can be realized with a simple configuration. As a result, the mechanism for causing the specific core 20b to appear and retract by the knocking operation can be made compact, and the writing instrument 1 can be prevented from becoming unnecessarily large.

In the writing instrument 1 according to the present embodiment, the second retraction mechanism M2 engages the cam portion 52 with the cam receiving portion 44b in the rotational direction when the knock portion 100 is pushed forward, thereby moving the front cylinder 11 forward. and the rear cylinder 12 are restricted to a specific rotation angle. As a result, a mechanism for restricting the rotation angle between the front cylinder 11 and the rear cylinder 12 to a specific rotation angle can be easily constructed, so that the second retraction mechanism M2 can be realized with a simpler construction.

In the writing instrument 1 according to the present embodiment, each of the cam portion 52 and the cam receiving portion 44b has a cylindrical shape with the axial direction D as the central axis direction, and the cam portion 52 is inclined from a plane perpendicular to the axial direction D. The cam surface 52a has a cross-sectional shape obtained by cutting the cylindrical shape on the flat plane, and the cam receiving portion 44b includes a cam receiving surface 44c corresponding to the cam surface 52a. is pushed forward, the rotation angle between the front cylinder 11 and the rear cylinder 12 is restricted to a specific rotation angle by engaging the cam surface 52a with the cam receiving surface 44c in the rotational direction. By simplifying the shape of the cam portion 52 and the cam receiving portion 44b in this way, it is possible to more easily construct a mechanism for restricting the rotation angle between the front cylinder 11 and the rear cylinder 12 to a specific rotation angle. . Further, since the cam portion 52 and the cam receiving portion 44b are easily molded, the manufacturing process of the writing instrument 1 can be simplified.

In the writing instrument 1 according to the present embodiment, the rotating cam 40 is restricted from advancing with respect to the front cylinder 11 by contacting the front cylinder 11 in the axial direction D, and between the cam portion 52 and the rotating cam 40, A spring S2 is provided to bias the rotary cam 40 forward with respect to the cam portion 52 . In this configuration, after the knock portion 100 is pushed down, the knock portion 100 is returned to its original position by the biasing force of the spring S2. Further, the position of the rotating cam 40 in the axial direction D with respect to the front cylinder 11 is maintained by urging the rotating cam 40 forward by the biasing force of the spring S2. In other words, the spring S2 has both a function of returning the knock portion 100 to its original position and a function of maintaining the position of the rotary cam 40 in the axial direction D. As shown in FIG. By providing one component with a plurality of functions in this manner, the number of components can be reduced and the configuration of the writing instrument 1 can be simplified.

In the writing instrument 1 according to the present embodiment, the movement restricting portion R restricts the rotating cam 40 from retreating toward the cam portion 52 with respect to the front cylinder 11 , while the cam portion 52 moves toward the rotating cam 40 with respect to the front cylinder 11 . may be allowed to advance to The movement restricting portion R restricts the retraction of the rotating cam 40 that causes the core 20 to appear and retract, thereby restricting the retraction of the core 20 into the barrel 10 . As a result, it is possible to suppress a situation in which the protruding core 20 receives writing pressure during writing and is retracted inside the barrel 10 . In addition, since the movement restricting portion R allows the cam portion 52 to move forward, it is possible to prevent the knock portion 100 from being pushed down by the movement restricting portion R.

In the writing instrument 1 according to this embodiment, the movement restricting portion R protrudes from the outer surface of the rear cylindrical portion 32 and includes an elastic protrusion 32a having elasticity in the radial direction. , the rotary cam 40 is restricted from retreating toward the cam portion 52 with respect to the front cylinder 11, and the elastic protrusion 32a is pushed forward by the rear cylinder portion 32 when the knock portion 100 is pushed forward. By moving inward, the cam portion 52 is allowed to advance toward the rotary cam 40 with respect to the front cylinder 11 . As a result, the movement restricting portion R that restricts the backward movement of the rotating cam 40 and permits the forward movement of the cam portion 52 can be realized with a simple configuration.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments and can be applied to various embodiments. For example, in the above-described embodiment, the cam portion 52 and the cam receiving portion 44b are engaged to regulate the rotation angle between the front cylinder 11 and the rear cylinder 12 to a specific rotation angle. The configuration for restricting the rotation angle between 11 and rear cylinder 12 to a specific rotation angle is not limited to this. For example, a cam shape corresponding to the cam receiving portion 44b may be directly formed on the rear end portion of the front cylinder 11, and a cam shape corresponding to the cam portion 52 may be directly formed on the front end portion of the rear cylinder 12. are brought into contact with each other, the rotation angle between the front cylinder 11 and the rear cylinder 12 may be restricted to a specific rotation angle. Even in this case, the same effects as those of the above embodiment can be obtained. Moreover, the cam portion 52 and the cam receiving portion 44b do not necessarily have to have a cylindrical shape, and various other shapes can be adopted.

Reference Signs List 1 Writing instrument 10 Axle tube 11 Front tube 12 Rear tube 13a Openings 20, 20a, 20c Core 21 Core holder 22 Slide piece 22a Protrusion 30 Middle piece 32 Rear cylinder ( cylindrical part)
32a... elastic protrusion 40... rotating cam 41... cam case 42... cam portion 42a... protrusion
42b... Recessed part 44b... Cam receiving part 44c... Cam receiving surface 52... Cam part 52a... Cam surface 100... Knock part D... Axial direction M1... First retracting mechanism M2... Second retracting mechanism R... Movement restricting part S1... Spring S2 …spring

Claims (6)

a barrel having an axis extending from a front end to a rear end and having an opening formed at the front end;
a core that is disposed inside the barrel and can be retracted from the opening;
a first retraction mechanism for retracting the core from the opening,
The first haunting mechanism is
a core holder that holds the core;
a slide piece including a first protrusion attached to the rear of the core holder and protruding rearward;
a first elastic member that biases the slide piece backward with respect to the core;
a middle piece that engages with the shaft cylinder, holds the middle core, and accommodates the slide piece so as to be slidable along the axial direction;
a rotating cam rotatable with respect to the middle piece and biased forward by a second elastic member having a biasing force stronger than that of the first elastic member;
The rotating cam includes a cylindrical cam case and a cam portion that is separate from the cam case and is slidable in the axial direction with respect to the cam case. A second projection projecting toward the projection and a recess that abuts against the first projection of the slide piece are provided, and the first projection of the slide piece abuts against the recess to move the core. A writing implement that protrudes outward from the opening. 2. The writing instrument according to claim 1, wherein said second protrusion and said recess of said cam portion are provided on an inner peripheral surface of said cam portion. 3. The writing instrument according to claim 1, wherein said cam portion is slidable along an inner peripheral surface of said cam case. The barrel has a front barrel in which the opening is formed and a rear barrel rotatably connected to the front barrel,
A plurality of the core, the core holder, the slide piece, and the first elastic member are provided,
4. The first protrusion/retraction mechanism according to any one of claims 1 to 3, wherein one of the plurality of cores is retracted and retracted from the opening according to a rotation angle between the front cylinder and the rear cylinder. 1. The writing instrument according to item 1. A knock portion is provided so as to be slidable in the axial direction with respect to the front cylinder, and when the knock portion is pushed down forward in the axial direction, a specific center core among the plurality of core cores is engaged. 5. The writing instrument according to claim 4, further comprising a second retractable mechanism that retracts outward from said opening. According to any one of claims 1 to 5, a mechanical pencil lead is delivered from the central core for a mechanical pencil, which is the central core, by moving the cam portion forward in the axial direction with respect to the cam case. Writing implements as described.

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