JP6793789B2 - Knock type writing instrument - Google Patents

Description

The present invention relates to a knock-type writing instrument.

The writing part, which is the pen tip of the refill, has an operation part at the rear end of the barrel and performs a knock operation that pushes the operation part forward against the urging force of the spring arranged in the barrel. There is known a so-called knock-type writing instrument that can switch between a writing state in which the writing instrument protrudes from the tip of the barrel and a non-writing state in which the writing portion is immersed in the barrel (for example, Patent Document 1). The change in the pressing force of the operating portion required to switch between the written state and the non-written state, that is, the change in the operating load depends on the spring constant of the spring. Therefore, when the operating unit is moved forward, the operating load required for the movement changes linearly according to the amount of movement.

In the writing instrument described in Patent Document 1, in the non-writing state, by setting the operating load of the knock body, that is, the operating portion to be larger than before, the writing portion unintentionally protrudes from the tip of the barrel, and a pocket of clothing or the like. It prevents it from getting dirty.

Japanese Unexamined Patent Publication No. 11-70779

However, if this operating load is set large, it is possible to prevent the writing part from unintentionally protruding from the tip of the barrel, but due to the impact when switching from the writing state to the non-writing state, the ink in the refill may be filled. Bubbles may be generated. That is, when switching from the written state to the non-written state, the refill moves vigorously backward by the urging force of the spring, and an impact is applied when the refill is stopped. In particular, when low-viscosity ink or shear-thinned ink is contained in the refill, the ink may recede due to the impact, and air may be mixed into the refill from the writing part. In this case, air bubbles may be generated in the ink, which may cause writing defects.

The present invention is a knock provided with a simple mechanism that prevents the operation unit from unintentionally moving in the non-writing state and minimizes the impact applied to the refill when switching from the writing state to the non-writing state. The purpose is to provide a formal writing instrument.

According to one aspect of the present invention, it is composed of a shaft cylinder, a writing body arranged in the shaft cylinder, a spring for urging the writing body rearward, and a protrusion provided on the inner surface of the shaft cylinder. A plurality of outer cams in which the protrusions extend in the front-rear direction and are arranged in the circumferential direction, and a guide groove extending in the front-rear direction is defined between the plurality of outer cams. An operating portion having a locking projection portion configured to be movable in the front-rear direction in the guide groove provided on the outer peripheral surface, and an operating portion having a cam surface formed on the front end surface and the inside of the guide groove. An inner cam configured to be movable in the front-rear direction is a rotor provided on the outer peripheral surface, and includes a rotor having a cam receiving surface having a shape complementary to the cam surface formed on the rear end surface. A writing state in which the rotor is rotated by the cam surface pressing the cam receiving surface, the inner cam engages with the outer cam, and a non-writing state in which the inner cam is housed in the guide groove. Provided is a knock-type writing tool capable of switching between and, wherein the operating load of the knock operation is not proportional to the movement amount of the operation unit when switching from the non-writing state to the writing state. To.

According to another aspect of the present invention, there is provided a knock-type writing instrument characterized in that the operating load is maximum at the time of initial movement of the knock operation in switching from the non-writing state to the writing state.

According to another aspect of the present invention, in the non-writing state, the locking protrusion of the operating portion is locked with the locked portion provided on the protrusion of the outer cam. A featured knock-type writing instrument is provided.

According to another aspect of the present invention, there is provided a knock-type writing instrument characterized in that the locked portion is a recess formed on a side surface of the protruding portion of the outer cam in the circumferential direction.

According to another aspect of the present invention, there is provided a knock-type writing instrument characterized in that the recess has a shape complementary to a part of the locking protrusion.

According to another aspect of the present invention, there is provided a knock-type writing instrument characterized in that the recess has a slope that guides the locking protrusion into the guide groove.

According to another aspect of the present invention, there is provided a knock-type writing instrument, wherein all or a part of the operation unit is an erasing unit capable of erasing the handwriting of the knock-type writing instrument.

According to another aspect of the present invention, the knock-type writing instrument is a knock-type writing instrument having heat-discoloring ink, and the handwriting by the heat-discoloring ink can be thermally discolored by the frictional heat generated when the knock-type writing instrument is rubbed by the erasing portion. A knock-type writing instrument characterized by being is provided.

According to the aspect of the present invention, a simple mechanism for preventing the operation unit from unintentionally moving in the non-writing state and minimizing the impact applied to the refill when switching from the writing state to the non-writing state is provided. It has the common effect of providing a equipped knock-type writing instrument.

It is a vertical cross-sectional view of the writing instrument in a non-writing state by embodiment of this invention. It is a vertical cross-sectional view of the writing state of the writing instrument of FIG. It is a perspective view of the rear axis of the writing instrument of FIG. It is an enlarged vertical sectional view of the rear end portion of the rear axle of FIG. It is a perspective view of the operation part of the writing part of FIG. It is a perspective view of the rotor of the writing instrument of FIG. It is a schematic diagram which shows the switching from the non-writing state to the writing state of the knock mechanism of the writing instrument of FIG. It is a conceptual diagram which shows the relationship between the knock operation and the operation load of an operation part. It is an enlarged vertical sectional view of the rear end portion of the rear shaft of the writing instrument according to another embodiment of the present invention. It is a perspective view of the operation part of the writing instrument by another embodiment of this invention. It is a vertical cross-sectional view of the writing instrument explaining the mode in which the operation part provided with the erasing member. It is a vertical sectional view of the writing instrument explaining the mode in which the operation part provided with another erasing member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A common reference code is attached to the corresponding components throughout the drawings.

FIG. 1 is a vertical cross-sectional view of a knock-type writing instrument 1 according to an embodiment of the present invention in a non-writing state, and FIG. 2 is a vertical cross-sectional view of the writing instrument 1 of FIG. 1 in a writing state.

The writing instrument 1 includes a barrel 4 formed in a tubular shape and having a front shaft 2 and a rear shaft 3, a refill 5 which is a cursive body arranged in the shaft cylinder 4 and having a writing portion 5a at one end, and a refill. It has a spring 6 for urging 5 to the rear, and a knock mechanism 10 arranged at the rear end of the axle 4, that is, the rear end of the rear shaft 3. The knock mechanism 10 has an outer cam 20, an operating portion 30 formed in a tubular shape, and a rotor 40. The front end portion of the front shaft 2 is formed in a tapered shape, and a through hole 2a for projecting the writing portion 5a of the refill 5 is formed. The rear end portion of the front shaft 2 is inserted and screwed inside the front end portion of the rear shaft 3.

In the present specification, in the axial direction of the writing instrument 1, the writing portion 5a side is defined as the "front" side, and the side opposite to the writing portion 5a is defined as the "rear" side. Further, in the writing instrument 1, the refill 5 moves in the barrel 4 in the front-rear direction by the knock mechanism 10. At this time, the state in which the writing portion 5a is immersed in the barrel 4 is referred to as a non-writing state (FIG. 1), and the state in which the writing portion 5a protrudes from the barrel 4 is referred to as a writing state (FIG. 2).

FIG. 3 is a perspective view of the rear shaft 3 of the writing instrument of FIG. 1, and FIG. 4 is an enlarged vertical sectional view of a rear end portion of the rear shaft 3 of FIG. In FIGS. 3 and 4, the upper side is the front of the writing instrument 1. On the inner surface of the rear end portion of the rear shaft 3, four outer cams 20 forming a part of the knock mechanism 10 are provided at equal intervals in the circumferential direction. Four guide grooves 21 extending in the front-rear direction are defined by two adjacent outer cams 20. Each of the outer cams 20 is composed of a first protrusion 22, a second protrusion 23, and a third protrusion 24 that extend in the front-rear direction and are continuously arranged in the circumferential direction. The second protrusion 23 arranged at the center has a thickness in the radial direction thinner than that of the first protrusion 22 and the third protrusion 24. Therefore, a radial recess is formed between the first protrusion 22 and the third protrusion 24, and the locking protrusion 31 of the operation portion 30, which will be described later, is formed between the first protrusion 22 and the third protrusion 24 at both ends. It is housed between the protrusion 24, that is, on the second protrusion 23.

On the side surface of the outer cam 20 in the circumferential direction, a locked recess 25, which is a recess in the circumferential direction, is formed as a locked portion. That is, the side surface 24a of the outer cam 20 facing the guide groove 21 of the third protrusion 24, in other words, behind the side surface 24a of the outer cam 20 opposite to the rotation direction of the rotor 40, as will be described later. A locked recess 25 is formed. The inner surface on the front side of the locked recess 25 is formed with a locked slope 26 that is inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction. Further, the locked recess 25 is formed with a bottom surface parallel to the side surface 24a of the third protrusion 24, that is, a side surface 27 of the third protrusion 24. Therefore, the locked slope 26 is a slope connecting the side surface 24a of the third protrusion 24 and the side surface 27 of the locked recess 25 parallel thereto.

FIG. 5 is a perspective view of the operation unit 30, the so-called knock rod, of the writing unit of FIG. In FIG. 5, the upper side is the front of the writing instrument 1. Eight locking projections 31 are provided on the outer peripheral surface on the front side of the operation unit 30 at equal intervals in the circumferential direction. Each of the locking protrusions 31 is knocked into the outer cam 20, more specifically, in the recess between the first protrusion 22 and the third protrusion 24, or in the guide groove between the outer cams 20. It is configured to move in the front-rear direction in 21. Further, a cam surface 32 is formed on the front end surface of the operation unit 30. The cam surface 32 has eight peaks 33 and valleys 34. The knock operation in the present specification means a series of operations in which the operation unit 30 is continuously pressed without interruption.

The locking projection 31 is formed so that its front end surface is included in a plane perpendicular to the front-rear direction, and a part thereof is a locking slope inclined in the circumferential direction with respect to the front end surface. 35 is formed. That is, on the front end surface of the locking protrusion 31, a locking slope 35 is formed on the rear portion on the side opposite to the rotation direction of the rotor 40, as will be described later.

FIG. 6 is a perspective view of the rotor 40 of the writing instrument of FIG. In FIG. 6, the upper side is the front of the writing instrument 1. The rotor 40 includes a small diameter portion 41 that is inserted into the operation portion 30 and used for centering, and a large diameter portion 42 that is arranged in front of the small diameter portion 41. The large diameter portion 42 has a larger diameter than the small diameter portion 41. A cam receiving surface 43 having a shape complementary to the cam surface 32 of the operating portion 30 is formed on the rear end surface of the large diameter portion 42. The cam receiving surface 43 has eight peaks 44 and valleys 45 like the cam surface 32 of the operation unit 30. On the outer peripheral surface of the large diameter portion 42, four inner cams 46 extending in the front-rear direction are provided at equal intervals in the circumferential direction. When the rotor 40 is rotated in the circumferential direction by the knock operation, the inner cam 46 engages with the outer cam 20 or is housed in the guide groove 21 between the outer cams 20. When the inner cam 46 is housed in the guide groove 21 between the outer cams 20, the outer cam 20 is housed in the groove 47 between the inner cams 46.

The cam surface 32 of the operation unit 30 and the cam receiving surface 43 of the rotor 40 have a ridge of the cam surface 32 when the inner cam 46 engages with the outer cam 20 or is housed in the guide groove 21 between the outer cams 20. The portion 33 is configured to be located on the slope between the adjacent mountain portion 44 and the valley portion 45 of the cam receiving surface 43 in the circumferential direction. Therefore, when the slope of the cam surface 32 presses the slope of the cam receiving surface 43 by the knock operation, the rotor 40 receives the component force in the circumferential direction due to the operating load and the urging force of the spring 6, and in the circumferential direction. Rotate. On the other hand, the operation unit 30 is restricted from rotating in the circumferential direction when the locking projection 31 abuts on the first protrusion 22 or the third protrusion 24 of the outer cam 20 in the circumferential direction.

FIG. 7 is a schematic view showing switching from the non-writing state to the writing state of the knock mechanism 10 of the writing instrument 1 of FIG. That is, FIG. 7 is a schematic view showing the positional relationship between the outer cam 20, the operation unit 30, and the rotor 40, and is a locking projection of the operation unit 30 with respect to the outer cam 20 expanded in the circumferential direction. It shows the position of the inner cam 46 of 31 and the rotor 40. In the figure, the upper part is the front side of the writing instrument 1, and the lower part is the rear part of the writing instrument 1. The rotor 40 is given a rotational force by the cam mechanism of the cam surface 32 of the operation unit 30 and the cam receiving surface 43 of the rotor 40 described above, and moves from left to right in the figure for each knock operation. In FIG. 7, for convenience, the first protrusion 22, the second protrusion 23, and the third protrusion 24 of the outer cam 20 are shown integrally, and the first protrusion 22 and the third protrusion 24 are referred to. The locking projection 31 of the operating portion 30 housed in the recess between them is omitted.

FIG. 7A is a schematic view of the knock mechanism 10 in the non-writing state of the writing instrument 1. At this time, the inner cam 46 of the rotor 40 urged rearward by the spring 6 via the refill 5 is housed in the guide groove 21 between the outer cams 20. Therefore, in this state, the writing portion 5a is immersed in the barrel 4. Further, the locking projection 31 of the operating portion 30 is housed in the guide groove 21 between the outer cams 20. The cam surface 32 of the operation unit 30 and the cam receiving surface 43 of the rotor 40 are in mesh with each other. That is, the peaks 33 and 34 of the cam surface 32 and the valleys 45 and 44 of the cam receiving surface 43 coincide with each other.

Further, the locking protrusion 31 of the operating portion 30 is accommodated in the locked recess 25 of the outer cam 20 to lock the locked protrusion 25 with respect to the movement in the front-rear direction, whereby the locked recess 25 is locked. The operation unit 30 is locked to the outer cam 20. That is, the locked recess 25 of the outer cam 20 is formed in a shape substantially complementary to a part of the locking protrusion 31 of the operating portion 30. More specifically, in this state, the locking slope 35 of the locking protrusion 31 of the operating portion 30 and the locked slope 26 of the locked recess 25 of the outer cam 20 are in contact with each other. Therefore, with respect to the force in the direction in which the locking protrusion 31 of the operating portion 30 tends to go out of the locked recess 25 of the outer cam 20, between the locking slope 35 and the locked slope 26. Friction force acts. Further, since the cam surface 32 of the operation unit 30 and the cam receiving surface 43 of the rotor 40 are in mesh with each other, the locking protrusion 31 of the operation unit 30 is outside the locked recess 25 of the outer cam 20. A component force in the circumferential direction in the opposite direction acts on the force in the direction to go out through the slopes of the cam surface 32 and the cam receiving surface 43.

FIG. 7B is a schematic view of the knock mechanism 10 when the operation unit 30 is pressed from the state of FIG. 7A and the lock between the operation unit 30 and the outer cam 20 is released. That is, when the operating load of the operating unit 30 exceeds the frictional force between the locking slope 35 and the locked slope 26 and the counterforce such as the above-mentioned component force in the circumferential direction, the operating unit 30 slightly rotates. Rotating in the direction, the locking protrusion 31 of the operating portion 30 and the locked recess 25 of the outer cam 20 are released from locking. The rotation of the operating portion 30 in the circumferential direction is generated by guiding the locking slope 35 of the operating portion 30 into the guide groove 21 along the locked slope 26 of the outer cam 20.

After that, the operation unit 30 rotor 40 advances mainly against the urging force of the spring 6, and at this time, the locking projection 31 of the operation unit 30 and the inner cam 46 of the rotor 40 are inside the guide groove 21. Move forward. Further, the operation unit 30 and the rotor 40 receive a component force in the circumferential direction in opposite directions via the slopes of the cam surface 32 and the cam receiving surface 43, but the first protrusion 22 and the first protrusion 22 of the outer cam 20 The movement in the circumferential direction is restricted by the side surface of the three protrusions 24.

FIG. 7C is a schematic view of the knock mechanism 10 when the operation unit 30 and the rotor 40 are further advanced. When the operation unit 30 and the rotor 40 are further advanced, the rear end portion of the inner cam 46 exceeds the front end portion of the outer cam 20, that is, the first protrusion 22 in the front-rear direction. At this time, the cam surface 32 and the cam receiving surface 43 coincide with each other, and the restriction on the movement of the rotor 40 in the circumferential direction by the side surface of the outer cam 20 is released.

FIG. 7D is a schematic view of the knock mechanism 10 in the writing state. When the pressing of the operation unit 30 is released from the state of FIG. 7C, the operation unit 30 and the rotor 40 are retracted by the urging force of the spring 6. At this time, since the movement of the rotor 40 in the circumferential direction by the side surface of the outer cam 20 is not restricted, the rotor 40 receives a component force from the slope of the outer cam 20 and receives a component force in the circumferential direction (viewed from the front). Sometimes counterclockwise). That is, the inner cam 46 of the rotor 40 moves until the slope of the outer cam 20 comes into contact with the side surface of the front end portion of the third protrusion 24. As a result, the inner cam 46 engages with the outer cam 20 to prevent the retreat, and the writing portion 5a is kept in a state of protruding from the barrel 4 via the refill 5 in contact with the rotor 40. , Writing becomes possible.

On the other hand, switching from the writing state of the knock mechanism 10 of the writing instrument 1 to the non-writing state is performed by pressing the operation unit 30 again from the state of FIG. 7D. That is, by pressing the operation portion 30, the rear end portion of the inner cam 46 exceeds the third protrusion 24 of the outer cam 20 in the front-rear direction. Next, when the pressing of the operating unit 30 is released, the operating unit 30 and the rotor 40 are retracted by the urging force of the spring 6. That is, the locking projection 31 of the operation unit 30 and the inner cam 46 of the rotor 40 move rearward in the guide groove 21 and stop, and are in a non-writing state. At this time, due to the component force in the circumferential direction via the slopes of the cam surface 32 and the cam receiving surface 43, the locking projection 31 of the operating portion 30 is engaged with the outer cam 20 as shown in FIG. 7A. It is housed in the retaining recess 25.

FIG. 8 is a conceptual diagram showing the relationship between the knock operation and the operation load of the operation unit 30. The horizontal axis indicates the position of the operation unit 30 in the front-rear direction, “OFF” is the position in the non-writing state, and “ON” is the position in the writing state. The vertical axis is the operating load of the operating unit 30 corresponding to the position of the operating unit 30 in the front-rear direction. The solid line A shows the relationship of the writing instrument 1 according to the present invention using the spring 6 having a spring constant half that of the conventional one, and the broken line B shows the relationship of the writing instrument 1 according to the present invention using the spring 6 having the same spring constant as the conventional one. Shown, the dotted line C shows the relationship of the conventional writing instrument.

With reference to the dotted line C indicating the conventional writing instrument, the position of the operation unit 30 and the operation load are in a substantially proportional relationship. On the other hand, referring to the broken line B showing the writing instrument 1 according to the present invention having the spring 6 having the same spring constant, a larger operating load is required in the initial movement of moving the operation unit 30. That is, in the non-writing state (OFF) where the total length of the spring 6 is the longest, the operating load for resisting the urging force of the spring 6 is the smallest, but in order to release the lock between the operating portion 30 and the outer cam 20. Requires a large operating load. Therefore, the solid line A showing the writing instrument 1 according to the present invention having the spring 6 having half the spring constant of the conventional one also shows the same tendency as the writing instrument 1 according to the present invention with the broken line B in the initial movement of moving the operation unit 30. ..

In order to move the operation unit 30 until the writing state (ON) is reached after the operation unit 30 and the outer cam 20 are unlocked, the writing instrument 1 according to the present invention of the broken line B and the conventional writing instrument of the dotted line C are used. Shows a similar tendency. That is, the operating load corresponds to the urging force of the spring 6, and the operating load required in the writing state in which the spring contracts most is substantially equal to or smaller than the operating load at the time of initial movement of the operating unit 30. On the other hand, according to the writing instrument 1 according to the present invention of the solid line A, the operating load required in the writing state in which the spring contracts most is approximately half of the operating load at the time of initial movement of the operating unit 30.

As described above with reference to FIGS. 7 (b) and 8, the writing instrument 1 according to the present invention requires a larger operating load in the initial movement of moving the operation unit 30 in the non-writing state. As a result, it is possible to prevent the operation unit 30 from unintentionally moving in the non-writing state with a simple mechanism. Further, when the operation unit 30 is formed of a material that can be erased by scraping the drawn lines, characters, etc. written by the writing instrument 1, and is configured as the erasing unit, it is possible to perform a stable scraping operation during the scraping operation. Become. That is, even if the writing instrument 1 is changed and the operation unit 30 is pressed against the writing surface to perform the scraping operation, the operation unit 30 does not rattle.

Further, usually, such a scraping operation is performed in a posture in which the writing instrument 1 is tilted with respect to the writing surface. Therefore, a pressing force in a direction inclined with respect to the front-rear direction is applied to the operating portion 30 of the inclined writing instrument 1 during the scraping operation. In the writing instrument 1, as described above, four of the eight locking projections 31 are locked to the locked recesses 25 of the four outer cams 20, and these are provided at equal intervals in the circumferential direction. ing. These lockings are primarily due to the frictional forces between the four corresponding locking slopes 35 and the locked slopes 26. The direction of the inclined pressing force with respect to the operation unit 30 is perpendicular to or nearly vertical to any one of the combinations of the four locking slopes 35 and the locked slope 26. Therefore, the operating load required at the time of initial movement is larger when the inclined pressing force is applied to the operating unit 30 than when the pressing force is applied forward along the axis line, so that a more stable scraping operation is performed. It becomes possible. The number of outer cams 20 and the number of locking protrusions 31 of the operation unit 30 can be arbitrarily set, but the larger the number, the lower the dependence on the tilting direction.

Further, if the spring constant of the spring 6 for urging the refill 5 to the rear is made smaller than before, the writing portion 5a is prevented from unintentionally protruding from the tip of the barrel 4, and bubbles in the ink are generated. It is possible to prevent writing defects caused by it. That is, when switching from the written state to the non-written state, the refill 5 vigorously moves backward by the urging force of the spring 6, and an impact is applied when the refill 5 is stopped. In particular, when low-viscosity ink or shear-thinned ink is contained in the refill 5, the ink recedes due to the impact, and air may be mixed into the refill 5 from the writing portion. In this case, air bubbles may be generated in the ink, which may cause writing defects. According to the present invention, since the spring constant of the spring 6 can be made smaller than before, the impact applied to the refill 5 when switching from the writing state to the non-writing state is minimized, and the generation of bubbles in the ink is suppressed. It becomes possible to do.

The operating load required at the time of initial movement can be arbitrarily changed by adjusting the shape of the locked recess 25 of the outer cam 20, for example, the inclination of the locked slope 26 and the area of the slope. Similarly, the operating portion 30 It can be arbitrarily changed by adjusting the shape of the locking projection 31, for example, the inclination of the locking slope 35 and the area of the slope. Thereby, it is possible to adjust the maximum value of the operating load at the time of the initial movement, not at the latter half of the knocking operation. As for the shape of a part of the locking protrusion 31 of the operating portion 30 and the locked recess 25 of the outer cam 20, any shape can be adopted as long as they can be locked to each other even if they are not complementary. Further, instead of the locked concave portion 25 of the outer cam 20, a convex portion is provided instead of a concave portion in the circumferential direction so that the outer cam 20 is locked with the locking protrusion 31 of the operation portion 30 so as to obtain the same effect. May be good. In this case, a concave portion may be used instead of the locking protrusion 31 of the operating portion 30. A modified example of the locked recess 25 of the outer cam 20 and a modified example of the locking protrusion 31 of the operating portion 30 will be described with reference to FIGS. 9 and 10.

FIG. 9 is an enlarged vertical sectional view of a rear end portion of the rear shaft 103 of the writing instrument 1 according to another embodiment of the present invention. Similar to the outer cam 20 shown in FIG. 4, four outer cams 120 forming a part of the knock mechanism 10 are equal to each other in the circumferential direction on the inner surface of the rear end portion of the rear shaft 103 shown in FIG. It is provided at intervals. The outer cam 120 shown in FIG. 9 differs from the outer cam 20 shown in FIG. 4 only in the shape of the locked recess, particularly the shape of the inner surface on the front side of the locked recess. That is, the outer cam 120 shown in FIG. 9 is formed with the locked recess 125 as in the outer cam 20 shown in FIG. 4, but the front side of the locked recess 125 of the outer cam 120 is formed. A locked slope 126 is partially formed on the inner surface of the above. In other words, the front surface 128 perpendicular to the front-rear direction is connected to the bottom surface or the side surface 127 of the locked recess 125, and then the locked slope 126 is connected.

By forming the front surface 128 in addition to the locked slope 126 in the locked recess 125, there are many design options for adjusting the operating load at the time of initial movement of moving the operation unit 30 in the non-writing state. ..

FIG. 10 is a perspective view of the operation unit 130 of the writing instrument 1 according to another embodiment of the present invention. Similar to the operation unit 30 shown in FIG. 5, eight locking projections 131 are provided on the outer peripheral surface on the front side of the operation unit 130 shown in FIG. 10 at equal intervals in the circumferential direction. The operation unit 130 shown in FIG. 10 differs from the operation unit 30 shown in FIG. 5 only in the shape of the locking protrusion, particularly the shape of the front end surface of the locking protrusion. That is, on the front end surface of the locking projection 31 shown in FIG. 5, a plane perpendicular to the front-rear direction and a locking slope 35 inclined in the circumferential direction with respect to the front end surface are formed. , The front end surface of the locking slope 135 shown in FIG. 10 does not have a plane perpendicular to the front-rear direction, and only the locking slope 135 is formed.

By forming only the locking slope 135 on the front end surface of the locking slope 135, there are many design options for adjusting the operating load at the time of initial movement of moving the operating portion 30 in the non-writing state.

FIG. 11 is a vertical sectional view of a writing instrument 201 for explaining an embodiment in which the operation unit 230 includes the erasing member 250. The outer shape of the operation unit 230 shown in FIG. 11 is the same as the outer shape of the operation unit 30 in the writing instrument 1 shown in FIG. 1, but the operation unit 230 has an erasing member 250 that functions as an erasing unit. The erasing member 250 is a tubular member that is attached by fitting to the rear end portion of the operating portion 230 and covers the operating portion 230. The erasing member 250 may be attached to the operation unit 230 by two-color molding or adhesion instead of fitting.

FIG. 12 is a vertical sectional view of a writing instrument 301 for explaining an embodiment in which the operation unit 330 includes another erasing member 350. The outer shape of the operation unit 330 shown in FIG. 12 is the same as the outer shape of the operation unit 30 in the writing instrument 1 shown in FIG. 1, but the operation unit 330 includes a columnar erasing member 350 that functions as an erasing unit. Have. The erasing member 350 is attached to the rear end of the operating portion 330, which is formed shorter in the front-rear direction than the operating portion 30 shown in FIG. 1, by adhesion, two-color molding, or the like. In other words, a part of the operation unit 330 functions as an erasing unit.

The cursive refill 5 in the present embodiment may contain a heat-discoloring ink. In this case, the writing instrument 1 is a heat-discoloring writing instrument, and the handwriting of the writing instrument 1 can be thermally discolored by the frictional heat generated when the writing instrument 1 is rubbed by the friction body which is the erasing portion. As the cursive, a ballpoint pen containing a heat-coloring ink, a mechanical pencil containing a heat-coloring core, a pencil holder, or the like can also be used.

Here, the thermochromic ink maintains a predetermined color (first color) at room temperature (for example, 25 ° C.), and when the temperature is raised to a predetermined temperature (for example, 60 ° C.), it changes to another color (second color). The ink has the property of returning to the original color (first color) when cooled to a predetermined temperature (for example, −5 ° C.). In the writing instrument 1 using the heat-changing ink, making the second color colorless and raising the temperature of the drawn line written in the first color (for example, red) to make it colorless is referred to as "erasing" here. .. Therefore, the writing surface or the like on which the drawn lines are written is rubbed by a friction body as an erasing portion to generate frictional heat, whereby the drawn lines are changed to colorless, that is, erased. As a matter of course, the second color may be a color other than colorless.

Two types of materials for forming the erasing portion include rubber materials such as silicone rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, and rubber elastic materials such as thermoplastic elastomers such as styrene elastomers, olefin elastomers, and polyester elastomers. Examples thereof include a mixture of the above rubber elastic materials, a mixture of the rubber elastic material and a synthetic resin, and a commercially available eraser. The erasing portion is particularly formed of a mixture of polypropylene resin and styrene-based thermoplastic elastomer, or a mixture of polypropylene resin and polypropylene-based thermoplastic elastomer, and the compounding ratio thereof is 1: 1 to 1: 4 by weight, respectively, and polishing is performed. It is made of a material that does not contain agents, plasticizers, or fillers and has a durometer hardness A of 70 ° to 100 ° specified in JIS K6251, and has the ability to erase pencil lines specified in JIS S 6050-2002 (erasing rate). ) Is 70% or less, and is formed from a low-wear elastic material containing no plasticizer. As a result, the erasing portion is effective because it is less likely to generate erasing residue when scraped and has excellent thermal discoloration.

The term "erasing" in the present invention means that the drawn lines, characters, etc. written are adsorbed or scraped off by an erasing part such as an eraser, in addition to the case where the above-mentioned heat-discoloring ink is used. Therefore, the present invention can be applied to any writing instrument that erases written lines by using an erasing unit.

1 Writing implement 4 Shaft cylinder 20 Outer cam 21 Guide groove 30 Operation part 31 Locking protrusion 32 Cam surface 40 Rotor 43 Cam receiving surface 46 Inner cam

Claims (1)

Shaft tube and
The cursive placed in the barrel and
A spring that urges the cursive backwards,
A plurality of outer cams composed of protrusions provided on the inner surface of the barrel, the protrusions extending in the front-rear direction and arranged in the circumferential direction, and in the front-rear direction between the plurality of outer cams. An outer cam with an extending guide groove defined,
An operation unit having a locking projection portion formed on the outer peripheral surface thereof so as to be movable in the front-rear direction in the guide groove, and an operation unit having a cam surface formed on the front end surface.
An inner cam configured to be movable in the front-rear direction in the guide groove is a rotor provided on the outer peripheral surface, and a cam receiving surface having a shape complementary to the cam surface is formed on the rear end surface. When,
Equipped with
A writing state in which the rotor is rotated by the cam surface pressing the cam receiving surface and the inner cam engages with the outer cam, and a non-writing state in which the inner cam is housed in the guide groove. Is a knock-type writing instrument that can be switched,
As engaged portion provided on the projecting portion of the outer cam in the circumferential direction, a concave portion is formed on a side surface of the protrusion of the outer cam,
In the non-writing state, the locking protrusion of the operating portion locks with the recess.
The engagement in the locking protrusion or the recess of the outer cam, knock-type writing instrument, wherein that you have been formed vertical plane and slope with respect to the longitudinal direction of the operation unit.

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