JP6545039B2 - mechanical pencil - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a mechanical pencil in which a writing core is fed by a fixed amount.

  As well known, the mechanical pencil carries out a predetermined amount of writing core from a spout member attached to the front end side of the barrel by knocking the knocking portion projecting to the rear end of the barrel. In general, not only mechanical pencils, but also writing instruments that can be erased by an erasing member provided in a knock portion such as a pencil with an eraser, are known (for example, Patent Document 1).

  In the writing instrument described in Patent Document 1, in order to prevent the back and forth movement of the erasing member in response to the erasing operation which inhibits the stable erasing operation, the movable member is supported with one point pivotally supported by the erasing member. I have a pin. When the erasing member is directed vertically downward during the erasing operation and the barrel is inclined, the movable pin is swung and locked to the barrel, whereby the erasing member is prevented from retreating and a stable erasing operation becomes possible. .

JP, 2015-20282, A

  However, in the writing instrument described in Patent Document 1, when the barrel is held perpendicular to the writing surface, the movable pin does not engage with the barrel and there is a possibility that a stable erasing operation can not be performed.

  An object of the present invention is to provide a mechanical pencil having a simple mechanism that enables stable erase operation and the like.

  According to one aspect of the present invention, there is provided a knock-type sharpening device including a shaft cylinder and an operation unit provided with an erasing member, wherein a writing operation is performed by performing a knocking operation to press the operation unit forward. A pencil, further comprising a knock lock member movable in the longitudinal direction in the shaft cylinder by gravity, and a locking portion provided on the inner surface of the shaft cylinder and capable of locking with the knock lock member. The mechanical pencil is characterized in that when the front end of the barrel is directed upward, the knock lock member moves rearward and locks with the locking portion, thereby preventing the forward movement of the operation portion. Provided.

  According to another aspect, there is provided a mechanical pencil characterized in that the knock lock member is a tubular member.

  Further, according to another aspect, the operation portion has a cam surface facing the knock lock member, the knock lock member has a cam receiving surface cooperating with the cam surface, and the knock lock member When moved rearward, the cam surface and the cam receiving surface cooperate to rotate the knock lock member in the circumferential direction, and the locking portion and the knock lock member are locked. Mechanical pencils are provided.

  Further, according to another aspect, when the knock lock member has a first projection and the locking portion has a second projection, the first lock is formed when the knock lock rotates in the circumferential direction. The mechanical pencil is characterized in that the knock lock member and the locking portion are locked by locking the second protrusion with the second protrusion.

  Further, according to another aspect, a recess is formed on the side surface of the first protrusion or the second protrusion, and the recess allows the first protrusion and the second protrusion to be engaged with each other. A mechanical pencil is provided which is characterized by stopping.

  Further, according to another aspect, the plurality of first protrusions and the plurality of second protrusions are arranged at equal intervals in the circumferential direction, and the first protrusion or the second protrusion is provided. A guide groove extending in the front-rear direction is defined between the projections of one of the parts, and the other of the projections moves in the guide groove in accordance with the movement of the knock lock member in the front-rear direction. A mechanical pencil featuring the features is provided.

  In addition, according to another aspect, there is provided a mechanical pencil characterized in that the recess has a slope for guiding the locking portion into the guide groove.

  In addition, according to another aspect, there is provided a mechanical pencil characterized in that the recess has a shape complementary to a part of the protrusion to be engaged.

  According to an aspect of the present invention, the common effect of providing a mechanical pencil having a simple mechanism that enables stable erase operation and the like can be achieved.

FIG. 1 is a longitudinal cross-sectional view of a mechanical pencil according to an embodiment of the present invention with the front end facing down. FIG. 2 is a longitudinal cross-sectional view of the mechanical pencil of FIG. 1 with the front end facing up. It is a front view of the rear shaft of the mechanical pencil of FIG. It is sectional drawing in line AA of the rear axis of FIG. It is a perspective view of the lead case of the mechanical pencil of FIG. It is a side view of the lead case of FIG. It is a perspective view of the knock lock member of the mechanical pencil of FIG. It is a side view of the knock lock member of FIG. It is a schematic diagram which shows operation | movement of the knock locking member of the mechanical pencil of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Corresponding components are given the same reference numerals throughout the drawings.

  FIG. 1 is a longitudinal cross-sectional view of a mechanical pencil 1 according to an embodiment of the present invention with the front end facing down, and FIG. 2 is a longitudinal cross-sectional view of the mechanical pencil 1 of FIG. In FIG. 1 and FIG. 2, the upper side is the vertical upper side, and the lower side is the vertical lower side. That is, gravity acts downward in each figure.

  The mechanical pencil 1 is attached to the front end of the front shaft 2 by a cylinder 4 formed in a cylindrical shape and provided with a front shaft 2 and a rear shaft 3, a grip 5 made of an elastic material attached around the front shaft 2, and It has the held tip member 6, the holding chuck 8 for holding the writing core 7, the spring 9, and the core case 10 formed in a cylindrical shape. The rear end portion of the holding chuck 8 is inserted and held in the front end portion of the lead case 10. Also, the lead case 10 is biased rearward by the spring 9 together with the holding chuck 8. The holding chuck 8 and the spring 9 constitute a known knock mechanism. In the present specification, in the axial direction of the mechanical pencil 1, the side from which the writing core 7 protrudes is defined as the "front" side, and the opposite side is defined as the "rear" side.

  An erasing member 20 is inserted into and fitted in the rear end portion of the lead case 10. A knock cover 21 whose one end is closed is fitted on the outer surface of the rear end portion of the lead case 10 to cover the erasing member 20. The erasing member 20 and the knock cover 21 protrude rearward from the rear end of the barrel 4. A knock lock member 30 is disposed around the lead case 10 in the barrel 4.

  As described later, the knock lock member 30 can move in the longitudinal direction in the barrel 4 by gravity. Therefore, in FIG. 1, since the front end of the mechanical pencil 1, that is, the front end of the barrel 4 is upward, the knock lock member 30 is closer to the rear end in the barrel 4. On the other hand, in FIG. 2, since the front end of the mechanical pencil 1, that is, the front end of the barrel 4 is downward, the knock lock member 30 is closer to the front end in the barrel 4 compared to FIG. 1.

  The erasing member 20 or the knock cover 21 functions as an operation unit. Therefore, the lead case 10 is pushed forward by the knocking operation for pressing the operation part forward against the biasing force of the spring 9, and the holding of the writing core 7 by the holding chuck 8 is released, and the writing core 7 is drawn out. Is done. As described later, the mechanical pencil 1 has a locking portion on the inner surface of the rear shaft 3, that is, the inner surface of the shaft cylinder, a point having the knock lock member 30, and a cam with which the core case 10 cooperates with the knock lock member 30. The structure is similar to that of the conventional mechanical pencil except that it has the surface 12.

  3 is a front view of the rear shaft 3 of the mechanical pencil 1 of FIG. 1, and FIG. 4 is a cross-sectional view of the rear shaft 3 of FIG. 3 taken along line A-A. In FIG. 4, the upper side is the front side of the mechanical pencil 1. A locking portion 40 is provided at an intermediate portion of the inner surface of the rear shaft 3. That is, the locking portion 40 is provided on the inner surface of the barrel 4. The locking portion 40 has four second protrusions 41 arranged at equal intervals in the circumferential direction, for locking with the first protrusions 32 of the knock lock member 30 described later. The second protrusion 41 has a trapezoidal cross section, and two parallel trapezoidal sides are arranged along the axial direction. The rear end surface of the second protrusion 41 is an inclined surface 42 which is inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction.

  5 is a perspective view of the lead case 10 of the mechanical pencil 1 of FIG. 1, and FIG. 6 is a side view of the lead case 10 of FIG. In FIG. 6, the upper side is the front side of the mechanical pencil 1. The core case 10 is a tubular member. On the outer peripheral surface of the rear end portion of the lead case 10, a fitting portion 11 which is an annular protrusion to be fitted to the knock cover 21 is formed. The outer peripheral surface of the front core case 10 of the fitting portion 11 is formed to have the largest diameter, and a cam surface 12 facing the front is formed. The cam surface 12 has four peaks 13 and valleys 14. More specifically, the ridges 13 and the cams 12 are formed so that the cam surface 12 has a slant 15 inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction and a longitudinal wall 16 extending along the front-rear direction. The valley portion 14 is configured. The ridges 13 of the cam surface 12 of the lead case 10 are asymmetrical along the circumferential direction, but may be symmetrical.

  FIG. 7 is a perspective view of the knock lock member 30 of the mechanical pencil 1 of FIG. 1, and FIG. 8 is a side view of the knock lock member 30 of FIG. In FIG. 8, the upper side is the front side of the mechanical pencil 1. The knock lock member 30 is a tubular member. The knock lock member 30 is disposed in the barrel 4 so as to be penetrated by the core case 10, and is movable in the front-rear direction between the rear end face 2a of the front shaft 2 and the cam surface 12 of the core case 10.

  A cam receiving surface 31 having a shape complementary to the cam surface 12 of the lead case 10 is formed on the rear end surface of the knock lock member 30. Similar to the cam surface 12 of the lead case 10, the cam receiving surface 31 has four peaks 31a and valleys 31b. That is, the cam receiving surface 31 of the knock lock member 30 has an inclined portion 31 c circumferentially inclined with respect to a plane perpendicular to the longitudinal direction, and a vertical wall portion 31 d extending along the longitudinal direction. A mountain portion 31a and a valley portion 31b are configured.

  Four first protrusions 32 are formed on the outer peripheral surface of the cylindrical portion 30 a of the knock lock member 30. The first protrusions 32 extend in the front-rear direction and are equally spaced in the circumferential direction. The adjacent first protrusions 32 define four guide grooves 33 extending in the front-rear direction.

  Recesses 34 in the circumferential direction are respectively formed on the side surface 32 a in the circumferential direction of the first protrusion 32, particularly on the side surface 32 a of the front end. The bottom surface of the recess 34 is a side surface 35 parallel to the side surface 32 a in the circumferential direction of the first protrusion 32. The inner surface on the rear side of the recess 34 is an inclined surface 36 which is inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction. The recess 34 is formed in a step shape as viewed from the front to the rear of the first protrusion 32. The side surface 35 of the first projection 32 plays a role of restricting circumferential rotation of the knock lock member 30.

  Each of the guide grooves 33 of the knock lock member 30 accommodates the second projection 41 of the locking portion 40 of the corresponding rear shaft 3 inside thereof, and allows the inside of the guide groove 33 to be relatively movable in the front and back direction. There is.

  The cam surface 12 of the lead case 10 and the cam receiving surface 31 of the knock lock member 30 are the same as those of the cam surface 12 when the second projection 41 of the locking portion 40 is accommodated in the guide groove 33 of the knock lock member 30. The ridge portion 13 is configured to be located on the inclined portion 31 c of the cam receiving surface 31 in the circumferential direction. Therefore, for example, when the front end of the mechanical pencil 1 is directed upward as shown in FIG. 2, the knock lock member 30 abuts against the cam surface 12 of the lead case 10 by the action of gravity. The knock lock member 30 rotates in the circumferential direction by receiving a component force in the circumferential direction.

  FIG. 9 is a schematic view showing the operation of the knock lock member 30 of the mechanical pencil 1 of FIG. That is, FIG. 9 is a schematic view showing the positional relationship between the cam surface 12 of the lead case 10, the knock lock member 30 and the locking portion 40 of the rear shaft 3, and the cam surface 12 of the lead case 10 is expanded in the circumferential direction. The positions of the first projection 32 of the knock lock member 30 and the second projection 41 of the rear shaft 3 are shown in FIG. In the figure, the upper side is the front side of the mechanical pencil 1 and the lower side is the rear side of the mechanical pencil 1.

  FIG. 9A is a schematic view of the interior of the rear shaft 3 with the front end of the mechanical pencil 1 as shown in FIG. 1 facing downward. Therefore, gravity acts upward in the figure. The knock lock member 30 is disposed on the front side between the rear end surface 2a of the front shaft 2 and the cam surface 12 of the lead case 10, and is stopped by abutment with the rear end surface 2a. Each of the second protrusions 41 of the rear shaft 3 is disposed in the guide groove 33 between the first protrusions 32 of the knock lock member 30.

  FIG.9 (b) shows the state in which lead case 10 advanced by knock operation from the state of Fig.9 (a). At this time, the knock lock member 30 does not lock with the locking portion 40, does not disturb the knocking operation, and the writing core 7 is pulled out according to the knocking operation.

  FIG. 9C is a schematic view of the inside of the rear shaft 3 immediately after the front end of the mechanical pencil 1 is directed upward, as shown in FIG. Therefore, gravity acts downward in the figure. By directing the front end of the mechanical pencil 1 upward, the knock lock member 30 moves rearward and abuts on the lead case 10. Specifically, the cam receiving surface 31 of the knock lock member 30 abuts on the cam surface 12 of the lead case 10. As described above, the knock lock member 30 rotates in the circumferential direction by receiving a component force in the circumferential direction caused by its own weight. That is, the cam surface 12 of the lead case 10 and the cam receiving surface 31 of the knock lock member 30 cooperate to rotate the knock lock member 30 in the circumferential direction, resulting in the state shown in FIG. 9D.

  FIG. 9D is a schematic view of the interior of the rear shaft 3 with the front end of the mechanical pencil 1 as shown in FIG. 1 facing upward. Therefore, gravity acts downward in the figure. As a result of the rotation of the knock lock member 30 described above, the knock lock member 30 locks with the locking portion 40, and the forward movement of the operation portion is blocked. That is, the knocking operation can not be performed.

  Specifically, the second projection 41 of the locking portion 40 is accommodated in the recess 34 of the first protrusion 32 of the knock lock member 30 so that the knock lock member 30 and the locking portion 40 are locked. It will be in the state. In other words, the recess 34 is formed of the second protrusion 41 of the locking portion 40 such that the second protrusion 41 of the locking portion 40 is accommodated in the recess 34 of the first protrusion 32 of the knock lock member 30. It is configured to be complementary to a part. Therefore, the slope 42 of the second protrusion 41 has the same inclination as the slope 36 of the recess 34. In this state, even if the operation part is strongly pressed and moved forward, the component force in the direction in which the second projection 41 of the locking part 40 is accommodated in the recess 34 of the knock lock member 30 is only strong That is, the locked state is not released.

  Here, when the front end of the mechanical pencil 1 is turned downward again from the state of FIG. 9 (d), the knock lock member 30 becomes free in relation to the cam surface 12 of the lead case 10. On the other hand, the knock lock member 30 presses the locking portion 40 via the first projection 32 by its own weight. That is, due to the weight of the knock lock member 30, the slope 36 of the recess 34 of the first protrusion 32 receives a component force in the circumferential direction from the slope 42 of the second protrusion 41 of the locking portion 40. As a result, the knock lock member 30 rotates in the circumferential direction opposite to that in the case of FIG. 9C, and the second projection 41 is guided into the guide groove 33. That is, the locked state between the knock lock member 30 and the locking portion 40 is released, and the knock lock member 30 is in a state where it can be moved forward. The forward movement of the knock lock member 30 is stopped by the contact with the rear end face 2a of the front shaft 2, and the state shown in FIG. 9A is obtained.

  In the present embodiment, as described with reference to FIG. 9D in particular, when the front end is in the upward state, the forward movement of the operation unit is blocked and the knock operation can not be performed. Therefore, for example, when erasing the handwriting with the mechanical pencil 1 using the erasing member 20 of the operation unit, it is possible to perform a stable rubbing operation. That is, even if the mechanical pencil 1 is replaced and the erasing member 20 is pressed against the writing surface to perform the rubbing operation, the erasing member 20 does not rattle.

  The knock lock member may have any shape as long as it can move in the longitudinal direction in the shaft cylinder. The number of first protrusions of the knock lock member and the number of second protrusions of the corresponding locking portion may be the same or different, and can be set arbitrarily. Therefore, each may be one or more than one. The shape of a portion of the first protrusion of the knock lock member and the shape of the recess of the second protrusion of the corresponding locking portion may be any shape as long as they can be locked to each other without being complementary. is there. Furthermore, in the embodiment described above, the first projection 32 provided on the knock lock member 30 is formed on the side of the barrel 4, and the second projection 41 provided on the barrel 4 is formed on the knock lock member 30. You may

  The writing core 7 described above may be a normal writing core of the same component as the pencil. In this case, the erasing member 20 can be a general eraser. The writing core 7 described above may be a thermochromic core containing a thermochromic pigment.

  Here, a thermochromic pigment maintains a predetermined color (first color) at normal temperature (for example 25 ° C.), and when heated up to a predetermined temperature (for example 60 ° C.) to another color (second color) And then cool down to a predetermined temperature (for example, -5.degree. C.), the pigment having the property of returning to the original color (first color) again. Here, in the mechanical pencil 1 using the writing core of the thermochromic pigment, “erasing” that the second color is made colorless, and the drawing line drawn in the first color (for example, red) is heated and made colorless. Let's say. Therefore, the writing surface or the like on which the drawn line has been written is abraded by the friction member as the erasing member to generate frictional heat, thereby changing the drawn line to colorlessness, ie, erasing it. As a matter of course, the second color may be a color other than colorless.

  When the writing core 7 is a thermochromic core, as a material for forming the erasing member 20, thermosetting rubber such as silicone rubber, nitrile rubber, ethylene propylene rubber, ethylene propylene diene rubber, styrene elastomer, olefin elastomer, A rubber elastic material such as a thermoplastic elastomer such as a polyester elastomer, a mixture of two or more rubber elastic materials, and a mixture of a rubber elastic material and a synthetic resin are loaded by a wear test (ASTM D1044) specified in JIS K7204. Under the environment of 9.8 N and 1000 rpm, the eraser member 20 is formed so that the amount of Taber abrasion at the abrasion wheel CS-17 of the Taber abrasion tester is 10 mg or more. Furthermore, in order to adjust the amount of Taber abrasion to be 10 mg or more, an alkylsulfonic acid phenyl ester, a cyclohexanedicarboxylic acid ester and a phthalic acid based plasticizer are used for the material of the erasing member 20 for more flexibility. You may add. Since the erasing member 20 contains the alkylsulfonic acid phenyl ester, cyclohexanedicarboxylic acid ester and phthalic acid plasticizer, the erasing member 20 is more easily worn, so the paper surface is not damaged and the printed characters and the like are not distorted. , The handwriting can be erased. Furthermore, the erasing member 20 preferably has a durometer D hardness of 30 or more as defined in JIS K6203. As a result, a predetermined hardness can be secured, and a more stable rubbing operation is possible. The erasing member 20 is also applicable as a touch pen or a stylus pen.

Reference Signs List 1 mechanical pencil 2 front shaft 3 rear shaft 4 shaft cylinder 7 writing core 10 core case 20 erasing member 30 knock lock member 40 locking portion

Claims (2)

A knock-type mechanical pencil comprising a shaft cylinder and an operation unit provided with an erasing member, wherein a writing operation is performed by performing a knock operation to press the operation unit forward,
A knock lock member movable in the longitudinal direction in the shaft cylinder by gravity and a locking portion provided on the inner surface of the shaft cylinder and capable of locking with the knock lock member are further provided.
When the front end of the barrel is directed upward, the knock lock member moves rearward and locks with the locking portion, thereby blocking the forward movement of the operation portion .
The operation portion has a cam surface facing the knock lock member, the knock lock member has a cam receiving surface that cooperates with the cam surface, and the knock lock member has a first projection. And the said locking part has a 2nd projection part, When the said 1st projection part and a said 2nd projection part latch when the said knock lock member rotates to a circumferential direction, the said knock lock member When the cam moves backward, the cam surface and the cam receiving surface cooperate to rotate the knock lock member in the circumferential direction, the lock portion and the knock lock member are locked, and A recess is formed on a side surface of the first protrusion or the second protrusion, and the recess causes the first protrusion and the second protrusion to be locked, thereby forming a plurality of the first protrusions. The protrusion and the plurality of second protrusions are each equally spaced in the circumferential direction And a guide groove extending in the front-rear direction between the protrusions of one of the first protrusion and the second protrusion, and the other protrusion being the front and rear of the knock lock member A mechanical pencil characterized in that it moves in the guide groove according to the movement of the direction, and the concave portion has an inclined surface for guiding the locking projection into the guide groove . A knock-type mechanical pencil comprising a shaft cylinder and an operation unit provided with an erasing member, wherein a writing operation is performed by performing a knock operation to press the operation unit forward,
A knock lock member movable in the longitudinal direction in the shaft cylinder by gravity and a locking portion provided on the inner surface of the shaft cylinder and capable of locking with the knock lock member are further provided.
When the front end of the barrel is directed upward, the knock lock member moves rearward and locks with the locking portion, thereby blocking the forward movement of the operation portion.
The operation portion has a cam surface facing the knock lock member, the knock lock member has a cam receiving surface cooperating with the cam surface, and the cam surface A mechanical pencil characterized by rotating the knock lock member in the circumferential direction in cooperation with the cam receiving surface, and the locking portion and the knock lock member are locked .

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