JP2017039296A - mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil comprising a simple mechanism which enables stable erasing operation and so on.SOLUTION: A knock-type mechanical pencil 1 comprises a barrel 4, and an operation part equipped with an erasing component 20. The mechanical pencil further comprises: a knock lock component 30 which performs a knock operation for pressing the operation part forwards to thereby deliver a writing core 7 and can be moved in a cross direction in the barrel 4 by gravity force; and a hook part 40 which is provided on an inner surface of the barrel 4 and can be hooked on the knock lock component 30. When a forward end of the barrel 4 is directed upwards, the knock lock component 30 is moved rearwards and is hooked on the hook part 40, and thereby forward movement of the operation part is blocked.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a mechanical pencil in which a writing core is drawn out by a certain amount.

  As is well known, a mechanical pencil knocks out a knock portion protruding from the rear end portion of the shaft cylinder, so that a predetermined amount of the writing core is fed out from the tip member attached to the front end side of the shaft cylinder. In general, a writing instrument that can erase not only a mechanical pencil but also a handwriting drawn on a writing surface such as a paper surface with an erasing member provided in a knock portion, such as a pencil with an eraser (for example, Patent Document 1).

  In the writing instrument described in Patent Document 1, in order to prevent the erasing member from moving back and forth according to the erasing operation, which inhibits a stable erasing operation, one point is movable with respect to the erasing member so as to be swingable. Has a pin. If the shaft cylinder is tilted while the erasing member is directed vertically downward during the erasing operation, the movable pin swings and engages with the shaft cylinder, thereby preventing the erasing member from retreating and enabling a stable erasing operation. .

Japanese Patent Laying-Open No. 2015-20282

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

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

  According to one aspect of the present invention, a knock-type sharp that includes a shaft cylinder and an operation unit that includes an erasing member, and that performs a knocking operation that pushes the operation unit forward, so that the writing core is extended. A pencil, a knock clock member that is movable in the longitudinal direction in the shaft cylinder by gravity, and a locking portion that is provided on the inner surface of the shaft cylinder and can be locked with the knock clock member; A mechanical pencil characterized in that when the front end of the shaft cylinder is directed upward, the knocking member is moved backward to be locked with the locking portion, and the forward movement of the operation portion is prevented. Provided.

  According to another aspect, there is provided a mechanical pencil wherein the knock clock member is a cylindrical member.

  According to another aspect, the operation portion has a cam surface facing the knock clock member, the knock clock member has a cam receiving surface that cooperates with the cam surface, and the knock clock member is When moved rearward, the cam surface and the cam receiving surface cooperate to rotate the knock clock member in the circumferential direction, and the locking portion and the knock clock member are locked. A mechanical pencil is provided.

  According to another aspect, the knock clock member has a first protrusion, the locking portion has a second protrusion, and the first clock member rotates in the circumferential direction. The mechanical pencil and the second projecting portion are engaged with each other, whereby the knocking member and the engaging portion are brought into an engaged state.

  According to another aspect, a recess is formed on a side surface of the first protrusion or the second protrusion, and the first protrusion and the second protrusion are engaged by the recess. A mechanical pencil is provided that is characterized by stopping.

  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 protrusions or the second protrusions. A guide groove extending in the front-rear direction is defined between one of the protrusions of the portion, and the other protrusion moves in the guide groove in accordance with the movement of the knock clock member in the front-rear direction. A mechanical pencil is provided.

  According to another aspect, there is provided a mechanical pencil characterized in that the concave portion has a slope that guides the projecting portion to be locked into the guide groove.

  According to another aspect, there is provided a mechanical pencil, wherein the concave portion has a shape complementary to a part of the protruding portion to be locked.

  According to the aspect of the present invention, there is a common effect of providing a mechanical pencil having a simple mechanism that enables a stable erasing operation and the like.

It is a longitudinal cross-sectional view of the mechanical pencil according to the embodiment of the present invention with the front end facing downward. It is a longitudinal cross-sectional view of the mechanical pencil of FIG. 1 with the front end facing upward. It is a front view of the rear axis | shaft of the mechanical pencil of FIG. FIG. 4 is a sectional view taken along line AA of the rear axis in FIG. It is a perspective view of the lead case of the mechanical pencil of FIG. FIG. 6 is a side view of the lead case of FIG. 5. It is a perspective view of the knockout member of the mechanical pencil of FIG. It is a side view of the knocklock member of FIG. It is a schematic diagram which shows operation | movement of the knockout 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 denoted by common reference symbols throughout the drawings.

  1 is a longitudinal sectional view of a mechanical pencil 1 according to an embodiment of the present invention with the front end facing downward, and FIG. 2 is a longitudinal sectional view of the mechanical pencil 1 of FIG. 1 with the front end facing upward. 1 and 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 formed in a cylindrical shape and includes a shaft cylinder 4 having a front shaft 2 and a rear shaft 3, a grip 5 made of an elastic material attached around the front shaft 2, and a front end of the front shaft 2. And a holding chuck 8 for holding the writing core 7, a spring 9, and a core case 10 formed in a cylindrical shape. The rear end portion of the holding chuck 8 is inserted and gripped in the front end portion of the lead case 10. The lead case 10 is urged rearward together with the holding chuck 8 by a spring 9. The holding chuck 8, the spring 9 and the like 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 and fitted in the rear end portion of the lead case 10. A knock cover 21 closed at one end is fitted to 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 shaft cylinder 4. In the shaft cylinder 4, a knock clock member 30 is disposed around the core case 10.

  As will be described later, the knock clock member 30 is movable in the axial direction in the axial tube 4 by gravity. Therefore, in FIG. 1, the front end of the mechanical pencil 1, that is, the front end of the shaft tube 4 is upward, and thus the knock clock member 30 is close to the rear end side in the shaft tube 4. On the other hand, in FIG. 2, since the front end of the mechanical pencil 1, that is, the front end of the shaft cylinder 4 faces downward, the knock clock member 30 is closer to the front end side in the shaft cylinder 4 than in FIG. 1.

  The erasing member 20 or the knock cover 21 functions as an operation unit. Accordingly, the lead case 10 is pushed forward by a knocking operation that pushes the operation portion forward against the urging force of the spring 9, the holding of the writing lead 7 by the holding chuck 8 is released, and the writing lead 7 is fed out. Is done. As will be described later, the mechanical pencil 1 includes a point having a locking portion on the inner surface of the rear shaft 3, that is, the inner surface of the shaft tube, a point having a knock clock member 30, and a cam in which the core case 10 cooperates with the knock clock member 30. Except for having the surface 12, the structure is the same as that of a conventional mechanical pencil.

  FIG. 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. 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 shaft tube 4. The locking part 40 has four second protrusions 41 arranged at equal intervals in the circumferential direction, which are locked with first protrusions 32 of the knock clock member 30 described later. The second protrusion 41 has a trapezoidal cross section, and is arranged so that two parallel sides of the trapezoid are along the axial direction. The rear end surface of the second protrusion 41 is a slope 42 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 lead case 10 is a cylindrical member. On the outer peripheral surface of the rear end portion of the core case 10, a fitting portion 11 that is an annular protrusion that fits with the knock cover 21 is formed. The outer peripheral surface of the core case 10 in front of the fitting portion 11 is formed to have the largest diameter, and a cam surface 12 facing forward is formed. The cam surface 12 has four peaks 13 and valleys 14. Specifically, the ridge 13 and the cam surface 12 have a slope portion 15 inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction and a vertical wall portion 16 extending along the front-rear direction. A valley 14 is formed. The crest portion 13 of the cam surface 12 of the lead case 10 is asymmetric along the circumferential direction, but may be symmetrical.

  7 is a perspective view of the knock clock member 30 of the mechanical pencil 1 of FIG. 1, and FIG. 8 is a side view of the knock clock member 30 of FIG. In FIG. 8, the upper side is the front side of the mechanical pencil 1. The knocklock member 30 is a cylindrical member. The knock clock member 30 is disposed so as to be penetrated by the core case 10 in the shaft cylinder 4, and is movable in the front-rear direction between the rear end surface 2 a 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 clock member 30. Similar to the cam surface 12 of the core case 10, the cam receiving surface 31 has four peak portions 31 a and valley portions 31 b. That is, the cam receiving surface 31 of the knock clock member 30 has an inclined portion 31c inclined in the circumferential direction with respect to a plane perpendicular to the front-rear direction and a vertical wall portion 31d extending along the front-rear direction. A mountain part 31a and a valley part 31b are formed.

  Four first protrusions 32 are formed on the outer peripheral surface of the cylindrical portion 30 a of the knock clock member 30. The first protrusions 32 extend in the front-rear direction and are arranged at equal intervals in the circumferential direction. Four guide grooves 33 extending in the front-rear direction are defined by the adjacent first protrusions 32.

  On the side surface 32a in the circumferential direction of the first protrusion 32, in particular, on the side surface 32a of the front end portion, a circumferential recess 34 is formed. 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 a slope 36 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 when viewed from the front to the rear of the first protrusion 32. The side surface 35 of the first projecting portion 32 plays a role of restricting the rotation of the knock clock member 30 in the circumferential direction.

  Each of the guide grooves 33 of the knock clock member 30 accommodates the second protrusion 41 of the locking portion 40 of the corresponding rear shaft 3 therein, and is relatively movable back and forth within the guide groove 33. Yes.

  The cam surface 12 of the lead case 10 and the cam receiving surface 31 of the knock clock member 30 are formed on the cam surface 12 when the second protrusion 41 of the locking portion 40 is received in the guide groove 33 of the knock clock member 30. The mountain portion 13 is configured to be positioned on the inclined portion 31c 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 clock member 30 comes into contact with the cam surface 12 of the core case 10 due to the action of gravity, but due to the dead weight of the knock clock member 30. The knock lock member 30 receives the circumferential component force and rotates in the circumferential direction.

  FIG. 9 is a schematic diagram showing the operation of the knock clock member 30 of the mechanical pencil 1 of FIG. That is, FIG. 9 is a schematic view showing the positional relationship among the cam surface 12 of the lead case 10, the knocking member 30 and the locking portion 40 of the rear shaft 3, and the cam surface 12 of the lead case 10 is developed in the circumferential direction. The positions of the first protrusion 32 of the knock lock member 30 and the second protrusion 41 of the rear shaft 3 are shown. In the drawing, 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 diagram in the rear shaft 3 in a state where the front end of the mechanical pencil 1 as shown in FIG. Therefore, gravity acts upward in the figure. The knock lock member 30 is disposed in front of the rear end surface 2a of the front shaft 2 and the cam surface 12 of the core case 10, and is stopped by contact 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 clock member 30.

  FIG. 9B shows a state where the lead case 10 has advanced from the state of FIG. 9A by a knocking operation. At this time, the knock clock member 30 is not locked with the locking portion 40 and does not hinder the knock operation, and the writing core 7 is fed out according to the knock operation.

  FIG. 9C is a schematic diagram in the rear shaft 3 in a state immediately after the front end of the mechanical pencil 1 faces upward as shown in FIG. Accordingly, gravity acts downward in the figure. By turning the front end of the mechanical pencil 1 upward, the knock clock member 30 moves rearward and comes into contact with 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 clock member 30 receives the circumferential force due to its own weight and rotates in the circumferential direction. That is, the cam surface 12 of the lead case 10 and the cam receiving surface 31 of the knock clock member 30 cooperate to rotate the knock clock member 30 in the circumferential direction, resulting in the state of FIG.

  FIG. 9D is a schematic diagram in the rear shaft 3 in a state in which the front end of the mechanical pencil 1 as shown in FIG. 1 is facing upward. Accordingly, gravity acts downward in the figure. As a result of the rotation of the knock clock member 30 described above, the knock clock member 30 is locked with the locking portion 40, and the forward movement of the operation portion is prevented. That is, the knock operation cannot be performed.

  Specifically, the second protrusion 41 of the locking part 40 is accommodated in the recess 34 of the first protrusion 32 of the knocking member 30 so that the knocking member 30 and the locking part 40 are locked. It becomes a state. In other words, the recessed portion 34 is formed on the second protruding portion 41 of the locking portion 40 so that the second protruding portion 41 of the locking portion 40 is accommodated in the recessed portion 34 of the first protruding portion 32 of the knocker member 30. It is configured to have a shape 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 portion is pressed strongly and moved forward, only the component force in the direction in which the second protrusion 41 of the locking portion 40 is accommodated in the recess 34 of the knock clock member 30 is increased. However, the locked state is not released.

  Here, when the front end of the mechanical pencil 1 is again turned downward from the state of FIG. 9D, the knocking member 30 becomes free in relation to the cam surface 12 of the lead case 10. On the other hand, the knock clock member 30 presses the locking portion 40 via the first protrusion 32 by its own weight. That is, due to the dead weight of the knock clock 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 part 40. As a result, the knock clock member 30 rotates in the circumferential direction opposite to that shown in FIG. 9C, and the second protrusion 41 is guided into the guide groove 33. In other words, the locked state of the knock clock member 30 and the locking portion 40 is released, and the knock clock member 30 becomes movable forward. The forward movement of the knock lock member 30 is stopped by contact with the rear end surface 2a of the front shaft 2, and the state shown in FIG.

  In the present embodiment, as described with reference to FIG. 9D in particular, when the front end is in the upward state, the operation unit is prevented from moving forward and a knock operation cannot be performed. Therefore, for example, when the handwriting is erased by the mechanical pencil 1 using the erasing member 20 of the operation unit, a stable rubbing operation can be performed. That is, even if the mechanical pencil 1 is changed and the erasing member 20 is pressed against the writing surface to perform the rubbing operation, the erasing member 20 will not rattle.

  The knock clock member may have any shape as long as it can move in the axial direction in the shaft cylinder. The number of the first protrusions of the knocklock member and the number of the second protrusions of the corresponding locking part may be the same or different, and can be arbitrarily set. Therefore, one each may be sufficient and two or more plural may be sufficient. In addition, the shape of the recesses of the first protrusions of the knocklock member and the second protrusions of the corresponding locking portions can be any shapes as long as they are not complementary and can be locked together. is there. Furthermore, in the above-described embodiment, the first protrusion 32 provided on the knock cylinder 30 is formed on the shaft cylinder 4 side, and the second protrusion 41 provided on the shaft cylinder 4 is formed on the knock clock member 30 side. May be.

  The above-described writing core 7 may be a normal writing core having 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, the thermochromic pigment means that when a predetermined color (first color) is maintained at room temperature (for example, 25 ° C.) and the temperature is raised to a predetermined temperature (for example, 60 ° C.), the color changes to another color (second color). The pigment has a property of returning to the original color (first color) again when cooled to a predetermined temperature (for example, −5 ° C.). In the mechanical pencil 1 using the writing core of the thermochromic pigment, the above-mentioned second color is made colorless and the drawn line written in the first color (for example, red) is heated to make it colorless. That is to say. Therefore, the friction surface as an erasing member rubs against the writing surface on which the drawn line is written to generate frictional heat, thereby changing the drawn line to colorless, that is, erasing. Of course, the second color may be a color other than colorless.

  When the writing core 7 is a thermochromic core, the material for forming the erasing member 20 is 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-based 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 an abrasion test (ASTM D1044) specified in JIS K7204. The erasing member 20 is formed so that the Taber wear amount on the wear wheel CS-17 of the Taber wear tester is 10 mg or more in a 9.8 N, 1000 rpm environment. Furthermore, in order to adjust the Taber abrasion amount to be 10 mg or more, alkylsulfonic acid phenyl ester, cyclohexanedicarboxylic acid ester and phthalic acid plasticizer for giving more flexibility to the material of the erasing member 20 are added. It may be added. When the erasing member 20 contains alkyl sulfonic acid phenyl ester, cyclohexanedicarboxylic acid ester or phthalic acid plasticizer, the erasing member 20 is more easily worn, so that the printed surface is not damaged and the printed characters are not distorted. The handwriting can be erased. Further, the erasing member 20 preferably has a durometer D hardness of 30 or more as defined in JIS K6203. Thereby, a predetermined hardness can be ensured and a more stable rubbing operation can be achieved. The erasing member 20 can also be applied as a touch pen or stylus pen.

DESCRIPTION OF SYMBOLS 1 Mechanical pencil 2 Front shaft 3 Rear shaft 4 Shaft cylinder 7 Writing core 10 Core case 20 Erasing member 30 Knock clock member 40 Locking part

Claims (3)

A knock-type mechanical pencil comprising a shaft cylinder and an operation unit provided with an erasing member, and performing a knocking operation to push the operation unit forward, whereby a writing core is extended.
A knocker member that can move in the longitudinal direction in the shaft cylinder by gravity; and a locking portion that is provided on the inner surface of the shaft cylinder and can be locked with the knock clock member;
When the front end of the shaft cylinder is directed upward, the knocking member moves rearward and engages with the engaging portion, and the operation portion is prevented from moving forward.   The mechanical pencil according to claim 1, wherein the knock lock member is a cylindrical member.   The operating portion has a cam surface facing the knocking member; the knocking member has a cam receiving surface that cooperates with the cam surface; the knocking member has a first protrusion; And the said latching | locking part has a 2nd projection part, and when the said knocking member rotates in the circumferential direction, when the said 1st projection part and the said 2nd projection part latch, the said knocking clock member Is moved rearward, the cam surface and the cam receiving surface cooperate to rotate the knock clock member in the circumferential direction, and the locking portion and the knock clock member are locked, A recess is formed on a side surface of the first protrusion or the second protrusion, and the first protrusion and the second protrusion are locked by the recess, and a plurality of the first protrusions are engaged. The protrusions and the plurality of second protrusions are equally spaced in the circumferential direction. And a guide groove extending in the front-rear direction is defined between one of the first protrusions and the second protrusions, and the other protrusion is disposed in front of and behind the knock clock member. 3. The sharp according to claim 1, wherein the concave portion has a slope that guides the projection to be locked into the guide groove while moving in the guide groove in accordance with a movement in a direction. Pencil.

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