JP6486782B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil capable of writing by manipulating a writing core by a predetermined amount from the tip of a base part by a knocking operation or the like.

  Conventionally, when writing with a mechanical pencil, if a high writing pressure is applied to the writing core, there is a problem that the writing core exposed from the tip of the base part is easily broken. When the writing pressure is constant, the writing core breaks down as the angle between the axial direction of the mechanical pencil barrel and the paper surface becomes smaller (so that the barrel is laid down), or the writing lead exposed from the tip of the base The longer the length is, the more conspicuous.

  In response to such a problem, Non-Patent Document 1 discloses a mechanism in which when a high writing pressure is applied to the writing core, a component in the axial direction of the writing pressure and a component perpendicular to the axial direction of the writing pressure are different. A mechanical pencil is described that absorbs the ink and reduces breakage of the writing core.

Specifically, in the mechanical pencil of Non-Patent Document 1, the base is supported by the shaft cylinder via an elastic body (coil spring), and the base has a tapered surface that gradually becomes smaller in diameter in the rearward direction in the axial direction. doing. In addition, a pressing portion that presses the tapered surface forward in the axial direction is formed in the shaft tube. With such a configuration, due to the component perpendicular to the axial direction of the pen pressure, the tapered surface of the base is pressed forward in the axial direction by the pressing portion of the shaft cylinder, and the base slides forward from the tip of the shaft cylinder. (Jump out). As a result, the length of the writing core exposed from the tip of the base is reduced. Further, in the mechanical pencil of Non-Patent Document 1, the core feeding unit for feeding out the writing core is formed by an elastic body (coil spring). In a state of being biased forward in the axial direction (the tip direction of the base in the axial direction), it is supported by the shaft cylinder so as to be relatively movable in the axial direction. The core feeding unit including the writing core moves relative to the axial tube rearward in the axial direction, whereby the axial component of the writing pressure is absorbed. As a result, the length of the writing core exposed from the tip of the base is further reduced, and the breakage of the writing core is reduced.

Zebra Corporation official website Internet <URL: http: // www. zebra. co. jp / pro / del_guard />

  However, the mechanical pencil described in Non-Patent Document 1 may not be able to sufficiently exhibit the ability to protrude the base forward from the tip of the shaft tube.

  As a result of intensive investigations to cope with this problem, the present inventor has found that by deforming the shaft tube, it is possible to sufficiently exhibit the performance of protruding the base forward from the tip of the shaft tube. It was.

  The present invention is based on the above-described knowledge, and the purpose thereof is to reliably avoid breakage of the writing core even when a high writing pressure is applied to the writing core, and the shaft cylinder. It is providing the mechanical pencil which can fully exhibit the performance which makes a nozzle | cap | die jump out from the front-end | tip of this.

  The present invention relates to a shaft cylinder having a rear shaft, a front shaft connected to the rear shaft and tiltable with respect to the rear shaft, and a core feeding for feeding a writing core supported in the shaft cylinder. A unit, a base having a writing core passage therein and supported in a front end region of the core feeding unit so as to be relatively movable in the axial direction, and a first tension provided on an outer peripheral surface of the front end region of the core feeding unit Compressed state between the protruding portion, the first protruding portion provided on the inner peripheral surface axially rearward of the first protruding portion of the base, and the first protruding portion and the first protruding portion A first elastic body that can be expanded and contracted, a second protrusion provided on an inner peripheral surface of a rear region of the rear shaft, and an outer periphery that is axially forward of the second protrusion of the core feeding unit. A second overhanging portion provided on the surface, and a stretchable arrangement arranged in a compressed state between the second projecting portion and the second overhanging portion Two elastic bodies, the base has a pressed portion in the rear region, the front shaft has a pressing portion in the front region, and the pressed portion and the pressing portion At least one is a tapered surface that gradually decreases in diameter toward the rear in the axial direction, and the pressing portion and the pressed portion are in contact with each other before the front shaft tilts with respect to the rear shaft. When the front shaft tilts with respect to the rear shaft, the pressing portion moves the pressed portion relative to the front end region of the core feeding unit in the axial direction. It is a mechanical pencil.

  According to the present invention, when the front shaft tilts with respect to the rear shaft, the pressing portion opposes the pressed portion against the urging force of the first elastic body and moves forward in the axial direction with respect to the front end region of the core feeding unit. Since the relative movement is made, the base can be reliably pressed forward in the axial direction. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

  Alternatively, the present invention provides a shaft cylinder having a rear shaft, a front shaft connected to the rear shaft and capable of bending deformation, and a core feeding unit for feeding a writing core supported in the shaft cylinder, A base having a passage for a writing lead therein and supported in the front end region of the lead feeding unit so as to be relatively movable in the axial direction; and a first overhanging portion provided on the outer peripheral surface of the front end region of the lead feeding unit; And a first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base, and being arranged in a compressed state between the first projecting portion and the first projecting portion. A first elastic body that can be expanded and contracted, a second protrusion provided on the inner peripheral surface of the rear region of the rear shaft, and an outer peripheral surface that is axially forward of the second protrusion of the core feeding unit. The second projecting portion formed, the second projecting portion, and the second projecting portion disposed in a compressed state in a compressible state. An elastic body, wherein the front shaft is made of a material having a Young's modulus of any value between 0.01 GPa and 10 GPa, and the base has a pressed portion in a rear region. The front shaft has a pressing portion in a front area, and at least one of the pressed portion and the pressing portion is a tapered surface that gradually becomes smaller in diameter toward the rear in the axial direction, and the front shaft Before the bending deformation, the pressing portion and the pressed portion are in contact with each other, and when the front shaft is bent and deformed, the pressing portion causes the pressed portion to move toward the front end of the core feeding unit. It is a mechanical pencil characterized by being moved relative to the region in the axial direction forward.

  According to the present invention, due to the bending deformation of the front shaft, the pressing portion moves the pressed portion relative to the front end region of the core feeding unit in the axial direction against the urging force of the first elastic body. Therefore, the base can be reliably pressed forward in the axial direction. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

  Alternatively, the present invention provides a shaft cylinder having a rear shaft and a front shaft disposed in front of the rear shaft and tiltable with respect to the rear shaft; A lead feeding unit for feeding out the writing core fixed to the inner peripheral surface, a base having a passage for the writing core inside and supported in a front end region of the lead feeding unit so as to be relatively movable in the axial direction; and A first projecting portion provided on the outer peripheral surface of the front end region of the core feeding unit; a first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base; A stretchable first elastic body disposed in a compressed state between one overhanging portion and the first projecting portion; a second projecting portion provided on an inner peripheral surface of a rear region of the front shaft; A second projecting portion provided on an outer peripheral surface axially forward of the second projecting portion of the lead feeding unit; the second projecting portion; A second elastic body that can be expanded and contracted arranged in a compressed state between the second projecting portion, the base has a pressed portion in the rear region, and the front shaft is in the front region. And at least one of the pressed portion and the pressing portion is a tapered surface that gradually decreases in diameter toward the rear in the axial direction, and the front shaft tilts with respect to the rear shaft. In the front, the pressing portion and the pressed portion are in contact with each other, and when the front shaft tilts with respect to the rear shaft, the pressing portion pushes the pressed portion of the lead feeding unit. The mechanical pencil is characterized by being moved relative to the front end region in the axial direction.

  Also according to the present invention, when the front shaft tilts with respect to the rear shaft, the pressing portion opposes the pressed portion against the urging force of the first elastic body and is relatively forward in the axial direction with respect to the front end region of the core feeding unit. Since it is made to move, a nozzle | cap | die can be reliably pressed to the axial direction front. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

  Alternatively, the present invention provides a shaft cylinder having a rear shaft and a front shaft that is disposed in front of the rear shaft and can be deformed, and is disposed in the shaft tube and fixed to the inner peripheral surface of the rear shaft. A lead feeding unit for feeding out the writing lead, a base having a passage for the writing lead therein and supported in a front end region of the lead feeding unit so as to be relatively movable in the axial direction, and a front end of the lead feeding unit A first projecting portion provided on an outer peripheral surface of the region, a first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base, and the first projecting portion. A first elastic body that can be expanded and contracted in a compressed state between the first projecting portion, a second projecting portion provided on an inner peripheral surface of a rear region of the front shaft, and the core feeding unit. A second projecting portion provided on an outer peripheral surface axially forward of the second projecting portion; the second projecting portion; and the second projecting portion. A second elastic body capable of expanding and contracting disposed in a compressed state between, and the front shaft is made of a material having a Young's modulus of any value between 0.01 GPa and 10 GPa, The base has a pressed part in the rear area, the front shaft has a pressed part in the front area, and at least one of the pressed part and the pressed part faces rearward in the axial direction. Before the front shaft is bent and deformed, the pressing portion and the pressed portion are in contact with each other, and when the front shaft is bent and deformed, The mechanical pencil is characterized in that the portion is configured to move the pressed portion relative to the front end region of the lead feeding unit in the axial direction.

  Also according to the present invention, due to the bending deformation of the front shaft, the pressing portion moves the pressed portion relative to the front end region of the core feeding unit in the axial direction against the urging force of the first elastic body. Therefore, the base can be reliably pressed forward in the axial direction. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

  In each of the above inventions, the core feeding unit has a core pipe extending in the axial direction of the shaft tube inside the shaft tube, and a protrusion formed on the outer peripheral surface fixed to the front end portion of the core pipe. A connector, a chuck fixed to the front end portion of the connector, a tightening ring externally fitted to a front region of the chuck, a return spring for urging the connector in the axial rearward direction, and a rear end of the core pipe A knock portion for pressing the core pipe forward in the axial direction, and a space formed between the shaft cylinder and the core pipe are arranged so as to loosely fit on the outer periphery of the core pipe. A weight body, and the weight body moves back and forth in the space when the shaft tube is swung back and forth, and abuts on the protrusion of the connector in the front. It is preferable that

  In this case, since the chuck is advanced in the axial direction by the inertial force of the weight body by swinging the shaft cylinder back and forth, the writing core can be quickly delivered without performing a knocking operation.

  Preferably, the pressed portion of the base is the tapered surface, and the tapered surface has any angle between 20 ° and 60 ° with respect to the axial direction of the shaft tube. The first elastic body is a first coil spring, and a load required to move the pressed portion relative to the core feeding unit in the axial direction against the urging force of the first coil spring is , Any value between 0.5N and 3N.

  In this case, when a high writing pressure is applied to the writing lead, the die can be reliably moved axially forward with respect to the front end region of the lead feeding unit, so that breakage of the writing lead is reliably avoided. On the other hand, when an appropriate writing pressure is applied to the writing core, the mouthpiece is not substantially moved forward relative to the front end region of the core feeding unit in the axial direction, so that the writing quality is not impaired.

Further preferably, the second elastic body is a second coil spring, and is necessary for moving the core feeding unit relative to the rear shaft in the axial rear direction against the urging force of the second coil spring. The load is any value between 1.5N and 4.5N. In this case, when a high writing pressure is applied to the writing lead, the lead feeding unit including the writing lead is axially oriented with respect to the shaft cylinder. Since the relative movement is reliably performed backward, breakage of the writing core is reliably avoided. On the other hand, when an appropriate writing pressure is applied to the writing core, the core feeding unit including the writing core is not substantially moved rearward in the axial direction with respect to the axial tube, so that the writing quality is not impaired. .

  According to the present invention, when the front shaft tilts with respect to the rear shaft, the pressing portion opposes the pressed portion against the urging force of the first elastic body and moves forward in the axial direction with respect to the front end region of the core feeding unit. Since the relative movement is made, the base can be reliably pressed forward in the axial direction. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

  Alternatively, according to the present invention, the pressing portion causes the pressed portion to move relative to the front end region of the core feeding unit forward in the axial direction against the urging force of the first elastic body by the bending deformation of the front shaft. Therefore, the base can be reliably pressed forward in the axial direction. Furthermore, the lead feeding unit can move relative to the axial tube rearward in the axial direction against the urging force of the first elastic body and the second elastic body. As a result, even when a high writing pressure is applied to the writing core, breakage of the writing core can be reliably avoided, and the performance of causing the base to jump forward from the tip of the shaft tube is sufficient. It can be demonstrated.

1 is a schematic side view of a mechanical pencil according to a first embodiment of the present invention. It is a schematic longitudinal cross-sectional view of the mechanical pencil of FIG. 2A is a schematic longitudinal sectional view of a mechanical pencil when no writing pressure is applied to the writing core, and FIG. 2B is a drawing in which a writing pressure perpendicular to the axial direction is applied to the writing core. FIG. 2C is a schematic longitudinal sectional view of the mechanical pencil when it is applied, and FIG. 2C is a mechanical pencil when the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to the writing core. FIG. It is a schematic side view of the mechanical pencil of the 2nd Embodiment of this invention. It is a schematic longitudinal cross-sectional view of the mechanical pencil of FIG. FIG. 4A is a schematic longitudinal sectional view of a mechanical pencil in the case where no writing pressure is applied to the writing core, and FIG. 4B is a drawing in which a writing pressure perpendicular to the axial direction is applied to the writing core. FIG. 4C is a schematic longitudinal cross-sectional view of the mechanical pencil when it is applied, and FIG. 4C is a mechanical pencil when the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to the writing core. FIG. It is a schematic longitudinal cross-sectional view of the mechanical pencil of the 3rd Embodiment of this invention. FIG. 5A is a schematic longitudinal sectional view of a mechanical pencil when no writing pressure is applied to the writing core, and FIG. 5B is a drawing in which a writing pressure perpendicular to the axial direction is applied to the writing core. FIG. 5C is a schematic longitudinal cross-sectional view of the mechanical pencil when it is applied, and FIG. 5C is a mechanical pencil when the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to the writing core. FIG. It is a schematic longitudinal cross-sectional view of the mechanical pencil of the 4th Embodiment of this invention. FIG. 6A is a schematic longitudinal sectional view of a mechanical pencil when no writing pressure is applied to the writing core, and FIG. 6B is a drawing in which a writing pressure perpendicular to the axial direction is applied to the writing core. FIG. 6C is a schematic longitudinal sectional view of the mechanical pencil when it is applied, and FIG. 6C is a mechanical pencil when the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to the writing core. FIG.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic side view of a mechanical pencil 100 according to a first embodiment of the present invention. 2 is a schematic longitudinal sectional view of the mechanical pencil 100 of FIG. 1, and FIG. 2 (a) is a schematic longitudinal section of the mechanical pencil 100 when no writing pressure is applied to the writing core 70. FIG. FIG. 2B is a schematic longitudinal sectional view of the mechanical pencil 100 when a writing pressure perpendicular to the axial direction is applied to the writing core 70, and FIG. It is a schematic longitudinal cross-sectional view of the mechanical pencil 100 in the case where the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to the writing core.

  As shown in FIGS. 1 and 2, the mechanical pencil 100 according to the present embodiment is a shaft having a polycarbonate rear shaft 20 and a front shaft 30 connected to the rear shaft 20 and tiltable with respect to the rear shaft 20. A cylinder 10, a core feeding unit 40 for feeding the writing core 70 supported in the shaft cylinder 10, and a passage for the writing core 70 therein, and a relative movement in the axial direction to the front end region of the core feeding unit 40 And a base 52 supported by the head. The base 52 of the present embodiment is configured as a base unit 50 including a cylindrical base member 51 made of brass fixed (screwed) to the front end region of the core feeding unit 40, and is axially connected to the base member 51. Is supported so as to be relatively movable.

  The front shaft 30 of the present embodiment is an injection-molded product made of polycarbonate, and is connected to the rear shaft 20 by being engaged with a cylindrical guide member 21 fixed in the rear shaft 20. Specifically, as shown in FIGS. 2A to 2C, the rear shaft 20 has a female screw portion 24 on the inner peripheral surface of the front region. The guide member 21 includes a small-diameter portion 21a that is axially forward (leftward in FIG. 2) and a large-diameter portion 21b that is axially rearward (rightward in FIG. 2). In the present embodiment, the large-diameter portion 21b has an outer diameter and an inner diameter larger than those of the small-diameter portion 21a, and has a male screw portion 22 on the outer peripheral surface. The guide member 21 is fixed to the rear shaft 20 by screwing the male screw portion 22 of the large diameter portion 21 b into the female screw portion 24 of the rear shaft 20.

  Further, the guide member 21 has an engaged portion 23 in the rear region of the small diameter portion 21a, and the front shaft 30 has an engaging portion 31 that engages with the engaged portion 23 in the rear end region. ing. Then, the engaging portion 31 of the front shaft 30 is engaged with the engaged portion 23 of the guide member 21 in a state where the guide member 21 is fixed (screwed) to the rear shaft 20. Is connected to the rear shaft 20. At this time, as shown in FIGS. 2A to 2C, the rear end region of the front shaft 30 includes an inner peripheral surface of a front region of the rear shaft 20 and an outer peripheral surface of the small diameter portion 21 a of the guide member 21. Is inserted in the gap formed between the two.

  In the present embodiment, the small diameter portion 21 a of the guide member 21 has an outer diameter that gradually decreases from the rear in the axial direction toward the front in the axial direction, and the outer peripheral surface of the small diameter portion 21 a and the inner periphery of the front shaft 30. A slight gap is formed between the surfaces. As a result, tilting of the front shaft 30 with respect to the rear shaft 20 is allowed.

  As shown in FIGS. 2A to 2C, the base member 51 of the base unit 50 of the present embodiment has a flange portion 53 as an overhang portion on the outer peripheral surface of the front region. The base 52 of the base unit has a protrusion 54 on the inner peripheral surface axially rearward of the flange 53, and the expansion and contraction is between the protrusion 54 and the flange 53 of the base member 51. A possible coil spring 55 is arranged in a compressed state. With such a configuration, the base 52 of the present embodiment can be moved relative to the base member 51 in the axial direction, for example, by 0.9 mm against the urging force of the coil spring 55.

  The front shaft 30 has a pressing portion 32 in the front end region. As shown in FIGS. 2A to 2C, the pressing portion 32 of the present embodiment is formed as a tapered surface that gradually becomes smaller in diameter toward the rear in the axial direction. The tapered surface has an angle of 45 ° with respect to the axial direction of the shaft tube 10.

  Further, the base 52 of the present embodiment has a tapered surface 56 as a pressed portion that gradually becomes smaller in diameter toward the rear in the axial direction in the rear region. The tapered surface 56 has an angle of 45 ° with respect to the axial direction of the shaft tube 10, and before the front shaft 30 tilts with respect to the rear shaft 20, The pressing portions 32 are in contact with each other. When the front shaft 30 tilts with respect to the rear shaft 20, the pressing portion 32 of the front shaft 30 moves the tapered surface 56 relative to the base member 51 in the axial direction forward. The load required to move the tapered surface 56 relative to the base member 51 in the axial direction relative to the urging force of the coil spring 55 of the present embodiment is 1.3 N.

  Further, the core feeding unit 40 of the present embodiment includes a polypropylene core pipe 41 extending in the axial direction of the shaft cylinder 10 inside the shaft cylinder 10, and a polyacetal resin fixed to the front end portion of the core pipe 41. A chuck 43 made of brass, a brass fastening ring 42 fitted in the front region of the chuck 43, a return spring 44 for urging the core pipe 41 axially rearward with respect to the shaft tube 10, a chuck 43, And an ABS resin outer cylinder 45 surrounding the core pipe 41.

  Specifically, as shown in FIGS. 2A to 2C, a protrusion 46 is formed on the inner peripheral surface of the front end region of the outer cylinder 45, and the chuck 43 is connected to the protrusion 46. It is slidably supported in the axial direction. A return spring 44 is disposed in a compressed state between the protruding portion 46 and the core pipe 41, and urges the core pipe 41 toward the axial direction rearward with respect to the outer cylinder 45. At this time, the chuck 43 is clamped by the fastening ring 42 so as not to retract the writing core 70. Further, the base member 51 of the base unit 50 has an abutting step portion 57 for restricting the forward movement of the fastening ring 42 in the middle of the front of the outer cylinder 45.

  The lead feeding unit 40 is attached to the rear end of the lead pipe 41 and further includes a knock portion 48 for pressing the lead pipe 41 axially forward against the outer cylinder 45. The knock portion 48 of the present embodiment is made of ABS resin, and has a sleeve portion 48a fitted on the rear end region of the core pipe 41 on the front side in the axial direction, and a cylindrical eraser 80 on the rear side in the axial direction. It has a holder part 48b that holds the holder in a removable manner. The internal space of the sleeve portion 48a and the internal space of the holder portion 48b are communicated by an opening. Thus, by removing the eraser 80 from the holder portion 48b, the writing core 70 can be put into the core holder 41 from the opening. A dome-shaped knob 81 that covers the back of the eraser 80 is detachably fitted to the holder portion 48b.

  As shown in FIGS. 2A to 2C, the lead feeding unit 40 is inserted into the guide member 21 and supported so as to be slidable in the axial direction with respect to the guide member 21. Yes. The guide member 21 of the present embodiment has a step portion 25 on the inner peripheral surface of the connection portion between the small diameter portion 21a and the large diameter portion 21b. Furthermore, the outer cylinder 45 of the core feeding unit 40 has a flange portion 47 having a larger diameter than the inner diameter of the small diameter portion 21a of the guide member 21 as an overhanging portion on the outer peripheral surface of the rear region. The step portion 25 and the flange portion 47 come into contact with each other, so that the relative movement of the outer cylinder 45 relative to the rear shaft 20 in the axial direction is restricted, and the lead feeding unit 40 is prevented from coming off. Yes.

  Further, as shown in FIGS. 2A to 2C, the rear shaft 20 has a protruding portion 26a on the inner peripheral surface of the rear region. In the present embodiment, the protruding portion 26a is formed at the front end portion of the polycarbonate head crown 26 that covers the rear end region of the core pipe 41 and is fixed by being fitted in the opening at the rear end of the rear shaft 20. ing. A retractable coil spring 60 is disposed in a compressed state between the protruding portion 26a and the flange portion 47 of the core feeding unit 40, and biases the core feeding unit 40 axially forward with respect to the rear shaft 20. doing. That is, the core feeding unit 40 is biased forward in the axial direction with respect to the base 52 via the base member 51 by the coil spring 55, and is pivoted with respect to the shaft cylinder 10 (rear shaft 20) by the coil spring 60. It is biased forward in the direction. The load required to move the lead feeding unit 40 relative to the axial cylinder 10 (rear shaft 20) in the axial rearward direction against the urging force of the coil spring 60 is 2.8N. In the present embodiment, as shown in FIGS. 2A to 2C, the coil spring 55 and the coil spring 60 are connected in series. The load required to move the lead feeding unit 40 relative to the shaft cylinder 10 (rear shaft 20) in the axial rearward direction against the urging force of the coil springs 55 and 60 is 4.1 N.

  In the present embodiment, as described above, the base member 51 can move relative to the base 52 in the axial direction, and the core feeding unit can move relative to the axial tube 10 (rear shaft 20) in the axial direction. It is. For this reason, when a high writing pressure is applied in the axial direction of the writing core 70, the core feeding unit 40 including the writing core 70 opposes the urging force of the coil spring 55 and the coil spring 60 against the axial cylinder 10. Thus, a relative movement of, for example, 2 mm is possible rearward in the axial direction.

  Next, with reference to FIG.2 (b) and FIG.2 (c), the effect | action of the mechanical pencil 100 of the 1st Embodiment of this invention is demonstrated.

  First, prior to writing on the paper, if necessary, the knob 81 and the eraser 80 are removed from the holder portion 48b, and the writing core 70 is formed through an opening that connects the sleeve portion 48a and the holder portion 48b. It is put into the core pipe 41. Then, the eraser 80 and the knob 81 are attached to the holder portion 48b, and the knock portion 48 (knob 81) is pressed (knocked) forward in the axial direction with the front end of the base unit 50 directed downward. As a result, the chuck 43 and the fastening ring 42 together with the core pipe 41 are advanced against the urging force of the return spring 44. In the middle of this forward movement, only the fastening ring 42 comes into contact with the contact step portion 57 formed on the base member 51 of the base unit 50. As a result, the fastening ring 42 is removed rearward from the chuck 43, the chuck 43 is released, and the writing core 70 is fed out.

  When the pressing state of the knock portion 48 (knob 81) is released, the core pipe 41 is retracted together with the chuck 43 by the urging force of the return spring 44. Along with this, the fastening ring 42 is fitted again to the front region of the chuck 43, and the chuck 43 is fastened. Thereby, the writing core 70 is clamped and the state where the writing core 70 is drawn out is maintained. Then, by repeating this series of pressing operations as appropriate, the writing core 70 is exposed (drawn out) for a desired length from the tip of the base 52 (see FIG. 2A). Then, the front shaft 30 is gripped by the user, and writing is performed by moving the shaft tube 10 as desired while bringing the writing core 70 into contact with the paper surface.

  In writing, the shaft tube 10 is generally gripped so that the axial direction forms an acute angle with respect to the paper surface. For this reason, a writing pressure including a component perpendicular to the axial direction of the shaft cylinder 10 and a component in the axial direction is applied to the writing core 70. When a high writing pressure is applied to the writing core 70 during writing, the mechanical pencil 100 according to the present embodiment absorbs a component perpendicular to the axial direction of the writing pressure and a component in the axial direction by different mechanisms, respectively. This prevents breakage of the writing core 70 exposed from the tip.

  Specifically, as shown in FIG. 2B, the front shaft 30 is tilted with respect to the rear shaft 20 by a component perpendicular to the axial direction of the writing pressure, and is pressed by the pressing portion 32 (tapered surface) of the front shaft 30. The tapered surface 56 of the base 52 is pressed forward in the axial direction. As a result, the base 52 is moved relative to the base member 51 in the axial direction against the urging force of the coil spring 55. That is, the length of the writing core 70 exposed from the tip of the base 52 is reduced.

  At the same time, as shown in FIG. 2C, the writing core 70 is pressed rearward in the axial direction against the axial tube 10 by the axial component of the writing pressure. Thereby, the core feeding unit 40 including the writing core 70 is relatively moved rearward in the axial direction against the urging force of the coil spring 55 and the coil spring 60. That is, the length of the writing core 70 exposed from the tip of the base 52 is further reduced, and breakage of the writing core 70 is avoided.

  When the writing pressure applied to the writing core 70 is weakened, the base 52 is pushed back in the axial direction by the biasing force of the coil spring 55, and the writing core 70 is included by the biasing force of the coil spring 55 and the coil spring 60. The lead feeding unit 40 is pushed back in the axial direction. As a result, the initial state (see FIG. 2A) is restored.

  Since the mechanism that absorbs the component perpendicular to the axial direction of the writing pressure and the mechanism that absorbs the component in the axial direction of the writing pressure operate independently of each other, they are high only in the direction perpendicular to the axial direction with respect to the writing core 70. When the writing pressure is applied, only the former mechanism works, and when the high writing pressure is applied only to the writing core 70 in the axial direction, only the latter mechanism works.

  According to the present embodiment as described above, when the front shaft 30 tilts with respect to the rear shaft 20, the pressing portion 32 (tapered surface) causes the tapered surface 56 of the base 52 to axially move with respect to the base member 51. Since the base 52 is relatively moved forward, the base 52 can be reliably pressed forward in the axial direction. Furthermore, the core feeding unit 40 can be moved relative to the axial tube 10 in the axially rearward direction against the urging force of the coil spring 55 and the coil spring 60. As a result, even when a high writing pressure is applied to the writing core 70, breakage of the writing core 70 can be reliably avoided, and the base 52 is protruded forward from the tip of the shaft tube 10. The performance can be fully exhibited.

  The tapered surface 56 of the base 52 has an angle of 45 ° with respect to the axial direction of the shaft tube 10, and the tapered surface 56 is axially directed with respect to the base member 51 against the urging force of the coil spring 55. The load required for relative movement forward is 1.3N. For this reason, when a high writing pressure is applied to the writing core 70, the base 52 is reliably moved relative to the base member 51 in the axial direction by the component perpendicular to the axial direction of the writing pressure. Breakage of the writing core 70 is reliably avoided. On the other hand, when an appropriate writing pressure is applied to the writing core 70, the mouthpiece 52 is not substantially moved relative to the base member 51 in the axial direction, so that the writing quality is not impaired.

  Further, the load required to move the lead feeding unit 40 relative to the shaft cylinder 10 (rear shaft 20) in the axial direction rearward against the urging force of the coil spring 60 is 2.8N. For this reason, when a high writing pressure is applied to the writing core 70, the core feeding unit 40 including the writing core 70 is reliably relative to the axial tube 10 rearward in the axial direction by the axial component of the writing pressure. Since it is moved, breakage of the writing core 70 is reliably avoided. On the other hand, when an appropriate writing pressure is applied to the writing core 70, the lead feeding unit 40 including the writing core 70 is not substantially moved rearward in the axial direction with respect to the shaft tube 10, so There is no loss.

  The front shaft 30 is not tilted with respect to the rear shaft 20, but the front shaft 30 is bent and deformed to move the base 52 relative to the base member 51 in the axial direction. Also good. In this case, the front shaft 30 can be made of a material having a Young's modulus of, for example, 2.3 GPa. In the present embodiment, a slight gap is formed between the outer peripheral surface of the small diameter portion 21a and the inner peripheral surface of the front shaft 30 as described above. For this reason, for example, the engagement portion 31 of the front shaft 30 and the engaged portion 23 of the guide member 21 are configured to be engaged with slight play, so that the front shaft 30 can be appropriately Bending deformation is realized (allowed).

  According to such a mechanical pencil, when the front shaft is bent and deformed, the pressing portion 32 (tapered surface) moves the tapered surface 56 of the base 52 relative to the base member 51 forward in the axial direction. Therefore, the base 52 can be reliably pressed forward in the axial direction. Furthermore, the core feeding unit 40 can be moved relative to the axial tube 10 in the axially rearward direction against the urging force of the coil spring 55 and the coil spring 60. As a result, even when a high writing pressure is applied to the writing core 70, breakage of the writing core 70 can be reliably avoided, and the base 52 is protruded forward from the tip of the shaft tube 10. The performance can be fully exhibited.

  Next, with reference to FIG.3 and FIG.4, the mechanical pencil 200 of the 2nd Embodiment of this invention is demonstrated.

  FIG. 3 is a schematic side view of the mechanical pencil 200 according to the second embodiment of the present invention. 4 is a schematic longitudinal sectional view of the mechanical pencil 200 of FIG. 3, and FIG. 4A is a schematic longitudinal sectional view of the mechanical pencil 200 when no writing pressure is applied to the writing core 270. 4 (b) is a schematic longitudinal sectional view of the mechanical pencil 200 when a writing pressure perpendicular to the axial direction is applied to the writing core 270, and FIG. 4 (c) is a writing core. It is a schematic longitudinal cross-sectional view of the mechanical pencil 200 when the writing pressure perpendicular to the axial direction and the writing pressure in the axial direction are applied to 270.

  As shown in FIGS. 3 and 4, the mechanical pencil 200 according to the present embodiment is disposed on a rear shaft 220 made of polycarbonate and in front of the rear shaft 220 (leftward in FIGS. 3 and 4). A shaft 210 having a front shaft 230 that can be tilted with respect to the shaft, and a writing core 270 that is disposed in the shaft tube 210 and is fixed (screwed) to the inner peripheral surface of the rear shaft 220. A lead feeding unit 240 and a base 252 having a passage for the writing lead 270 therein and supported in the front end region of the lead feeding unit 240 so as to be relatively movable in the axial direction are provided. The base 52 of the present embodiment is also configured as a base unit 250 including a base member 251 made of brass fixed (screwed) to the front end region of the core feeding unit 240, and moves relative to the base member 251 in the axial direction. Supported as possible.

  Further, in the present embodiment, a polycarbonate head crown 218 is fitted and fixed in an opening at the rear end in the rear shaft 220. The head crown 226 has a sleeve portion 226 a in the front region, and the sleeve portion 226 a extends along the inner peripheral surface of the rear shaft 220 to the vicinity of the front end portion of the rear shaft 220. A female screw portion is formed on the inner peripheral surface of the front end region of the sleeve portion 226a, and a male screw portion formed on the outer peripheral surface of the rear region of the outer cylinder 245 of the core feeding unit 240 is screwed to the male screw portion. It is fixed.

  Further, the front shaft 230 of the present embodiment is an injection-molded product made of polycarbonate, as in the first embodiment, and the outer peripheral surface of the front region is covered with rubber. A pressing portion 232 is provided in the front end region of the front shaft 230. As shown in FIGS. 4A to 4C, the pressing portion 232 of the present embodiment is formed as a tapered surface that gradually decreases in diameter toward the rear in the axial direction (rightward in FIG. 4). . The tapered surface has an angle of 45 ° with respect to the axial direction of the shaft cylinder 210.

  In the first embodiment, the expandable / contractable coil spring 60 is disposed between the protruding portion 26a on the inner peripheral surface of the rear shaft 20 and the flange portion 47 of the core feeding unit 40 in a compressed state. In the present embodiment, as shown in FIGS. 4A to 4C, the coil spring 260 that can be expanded and contracted includes the protrusion 233 on the inner peripheral surface of the front shaft 230 and the flange of the core feeding unit 240 in a compressed state. It arrange | positions between the parts 247. The front end of the rear shaft 220 is pressed against the rear end of the front shaft 230 by the biasing force of the coil spring 260. The load required to move the lead feeding unit 240 relative to the front shaft 230 in the axial rearward direction against the urging force of the coil spring 260 of the present embodiment is 2.8N.

  Further, a slight gap is formed between the radially outer end of the protruding portion 233 and the inner peripheral surface of the front shaft 230 in the present embodiment. As a result, tilting of the front shaft 230 with respect to the rear shaft 220 is allowed.

  Other configurations are the same as those of the mechanical pencil 100 of the first embodiment. 3 and 4 (a) to 4 (c), components similar to those of the first embodiment are denoted by substantially the same reference numerals, and detailed description thereof is omitted.

  Next, with reference to FIG.4 (b) and FIG.4 (c), the effect | action of the mechanical pencil 200 of the 2nd Embodiment of this invention is demonstrated.

  First, as in the first embodiment, the writing core 270 is exposed from the tip of the base 252 (see FIG. 4A), the front shaft 230 is gripped, and writing is performed on the paper surface.

  Similar to the first embodiment, the mechanical pencil 200 of the present embodiment also has a component perpendicular to the axial direction of the writing pressure and a component in the axial direction when a high writing pressure is applied to the writing core 270 during writing. Absorption is performed by different mechanisms, and breakage of the writing core 270 exposed from the tip of the base 252 is avoided.

  Specifically, as shown in FIG. 4B, the front shaft 230 is tilted with respect to the rear shaft 220 by a component perpendicular to the axial direction of the writing pressure, and is pressed by the pressing portion 232 (tapered surface) of the front shaft 230. The tapered surface 256 of the base 252 is pressed forward in the axial direction. As a result, the base 252 is relatively moved forward in the axial direction with respect to the base member 251 against the urging force of the coil spring 255. That is, the length of the writing core 270 exposed from the tip of the base 252 is reduced.

  At the same time, as shown in FIG. 4 (c), the writing core 270 is pressed axially rearward against the shaft cylinder 210 by the axial component of the writing pressure. Accordingly, the core feeding unit 240 including the writing core 270 is moved relative to the front shaft 230 in the axial rearward direction against the urging force of the coil spring 255 and the coil spring 260. That is, the length of the writing core 270 exposed from the tip of the base 252 is further reduced, and breakage of the writing core 270 is avoided. At this time, in the present embodiment, as shown in FIG. 4C, the core feeding unit 240 and the rear shaft 220 are integrally moved relative to the front shaft 230 in the axial direction rearward. For this reason, a gap corresponding to the amount of relative movement is formed between the rear end portion of the front shaft 230 and the front end portion of the rear shaft 220 in the state of relative movement. This informs the user that high writing pressure is being applied to the writing core 270 and prompts the user to relax the writing pressure.

  As in the first embodiment, when the writing pressure applied to the writing core 270 is weakened, the base 252 is pushed back in the axial direction by the biasing force of the coil spring 255 and the biasing forces of the coil spring 255 and the coil spring 260 are also applied. As a result, the lead feeding unit 240 including the writing lead 270 is pushed back in the axial direction. As a result, the initial state (see FIG. 4A) is restored.

  Also in the present embodiment, the mechanism that absorbs the component perpendicular to the axial direction of the writing pressure and the mechanism that absorbs the component of the axial direction of the writing pressure operate independently of each other. When a high writing pressure is applied only in the direction perpendicular to the axis, only the former mechanism acts. When a high writing pressure is applied only in the axial direction to the writing core 270, only the latter mechanism is applied. Act.

  According to the present embodiment as described above, when the front shaft 230 tilts with respect to the rear shaft 220, the pressing portion 232 (tapered surface) axially moves the tapered surface 256 of the base 252 with respect to the base member 251. Since the base 252 is relatively moved forward, the base 252 can be reliably pressed forward in the axial direction. Furthermore, the core feeding unit 240 can be moved relative to the axial tube 210 rearward in the axial direction against the urging force of the coil spring 255 and the coil spring 260. As a result, even when a high writing pressure is applied to the writing core 270, breakage of the writing core 270 can be reliably avoided, and the base 252 can be projected forward from the tip of the shaft tube 210. The performance can be fully exhibited.

  Further, the tapered surface 256 of the base 252 has an angle of 45 ° with respect to the axial direction of the shaft tube 210, and the tapered surface 256 is opposed to the base member 251 in the axial direction against the urging force of the coil spring 255. The load required for relative movement forward is 1.3N. For this reason, when a high writing pressure is applied to the writing core 270, the base 252 is reliably moved relative to the base member 251 in the axial direction by a component perpendicular to the axial direction of the writing pressure. Breakage of the writing core 270 is reliably avoided. On the other hand, when an appropriate writing pressure is applied to the writing core 270, the base 252 is not substantially moved relative to the base member 251 in the axial direction, so that the writing quality is not impaired.

  Furthermore, the load required to move the lead feeding unit 240 relative to the front shaft 230 in the axial rearward direction against the urging force of the coil spring 260 is 2.8 N. For this reason, when a high writing pressure is applied to the writing core 270, the lead feeding unit 240 including the writing core 270 reliably moves relative to the axial tube 210 in the axial direction rearward due to the axial component of the writing pressure. Therefore, breakage of the writing core 270 is surely avoided. On the other hand, when an appropriate writing pressure is applied to the writing core 270, the lead feeding unit 240 including the writing core 270 is not substantially relatively moved rearward in the axial direction with respect to the shaft cylinder 210. There is no loss.

  The front shaft 230 is not tilted with respect to the rear shaft 220, but the front shaft 230 is bent and deformed to move the base 252 relative to the base member 251 in the axial direction. Also good. In this case, the front shaft 230 can be made of a material having a Young's modulus of, for example, 2.3 GPa. As described above, a slight gap is formed between the radially outer end of the protrusion 233 of the front shaft 230 and the inner peripheral surface of the front shaft 230, so that Appropriate bending deformation is realized (allowed).

  According to such a mechanical pencil, when the front shaft is bent and deformed, the pressing portion 232 (tapered surface) moves the tapered surface 256 of the base 252 relative to the base member 251 in the axial direction forward. Therefore, the base 252 can be reliably pressed forward in the axial direction. Furthermore, the core feeding unit 240 can be moved relative to the axial tube 210 rearward in the axial direction against the urging force of the coil spring 255 and the coil spring 260. As a result, even when a high writing pressure is applied to the writing core 270, breakage of the writing core 270 can be reliably avoided, and the base 252 can be projected forward from the tip of the shaft tube 210. The performance can be fully exhibited.

  Next, a mechanical pencil 300 according to a third embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is a schematic longitudinal sectional view of the mechanical pencil 300 according to the third embodiment of the present invention. FIG. 5A shows the mechanical pencil 300 when no writing pressure is applied to the writing core 370. 5 (b) is a schematic longitudinal sectional view of the mechanical pencil 300 when a writing pressure perpendicular to the axial direction is applied to the writing core 370. FIG. (C) is a schematic longitudinal sectional view of the mechanical pencil 300 when a writing pressure perpendicular to the axial direction and a writing pressure in the axial direction are applied to the writing core 370.

  Unlike the first embodiment, the mechanical pencil 300 of the present embodiment includes a swing-out type core feeding unit 340. Specifically, the core feeding unit 340 of the present embodiment includes a polypropylene core pipe 341 that extends in the axial direction of the shaft tube 310 inside the shaft tube 310, and an outer periphery fixed to the front end portion of the core pipe 341. A connector 349 made of polyacetal resin having a protrusion formed on the surface, a chuck 343 fixed to the front end of the connector 349, a fastening ring 342 externally fitted to the front region of the chuck 343, and the connector 349 in the rearward direction in the axial direction A return spring 344 that urges (rightward in FIG. 5) and an ABS resin knocking portion that is attached to the rear end of the core pipe 341 and presses the core pipe 341 forward in the axial direction (leftward in FIG. 5). 348, and a weight body 390 disposed so as to be loosely fitted on the outer periphery of the core pipe 341 in a space formed between the shaft tube 310 and the core pipe 341. The has. As the weight body 390, for example, a weight having a weight of 2.3 g formed by winding a wire around an axis and forming a cylindrical shape can be adopted.

  The weight body 390 of the present embodiment has a protrusion formed on the connector 349 at the front in the axial direction by moving back and forth inside the space when the shaft 310 is swung back and forth (left and right in FIG. 5). It comes into contact with the portion 349a. When the connector 349 is brought into contact with the weight body 390, the connector 349 is advanced in the axial direction by the inertial force of the weight body 390.

  In addition, the crown 326 of the present embodiment has a step portion 326b on the inner peripheral surface, and the inner diameter of the step portion 326b in the axial direction rearward is larger than the inner diameter of the step portion 326 in the axial direction frontward. Yes. A flange portion 348c is formed on the outer periphery of the holder portion 348b of the knock portion 348, and a compressible spring 348d that can be expanded and contracted is disposed between the flange portion 348c and the step portion 326b of the head crown 326. Yes.

  Other configurations are the same as those of the mechanical pencil 100 of the first embodiment. 5A to 5C, components similar to those in the first embodiment are denoted by substantially the same reference numerals, and detailed description thereof is omitted.

  Next, the operation of the mechanical pencil 300 of the present embodiment will be described.

  In the mechanical pencil 300 of the present embodiment, the weight tube 390 is swung back and forth so that the weight body 390 passes through the space formed between the shaft tube 310 and the core pipe 341 to the connector 349 in the axial direction front. Until it abuts, it is moved back and forth in the axial direction until it abuts against the protrusion 326a of the crown 326. When the weight body 390 moves forward, the inertial force of the weight body 390 causes the connector 349, the chuck 343, and the fastening ring 342 to move forward against the urging force of the return spring 344. In the middle of this advancement, only the fastening ring 342 contacts the contact step 357 formed on the base member 351 of the base unit 350. Thus, the fastening ring 342 is removed from the chuck 343 in the axial direction, the chuck 343 is opened, and the writing core 370 is fed out.

  Then, when the influence of the inertial force of the weight body 390 on the connector 349 is eliminated, the connector 349 is retracted by the urging force of the return spring 344. Along with this, the chuck 343 engaged with the connector 349 is also retracted, and the fastening ring 342 is fitted on the front region of the chuck 343 again, and the chuck 343 is fastened. Thereby, the writing core 370 is clamped and the state where the writing core 370 is drawn out is maintained. Then, by repeating the longitudinal movement of the shaft tube 310 as described above, the writing core 370 is exposed (drawn) from the tip of the base 352 for a desired length (see FIG. 5A).

  In the mechanical pencil 300 of the present embodiment, the writing core 370 is fed out by pressing (knocking) the knock portion 348 as in the first embodiment. At the time of pressing (knocking), an appropriate resistance is brought about by the urging force of the spring 348d disposed between the flange portion 348c of the knock portion 348 and the step portion 326b of the head crown 326.

  Further, when a high writing pressure is applied to the writing core 370, the component perpendicular to the axial direction of the writing pressure and the component in the axial direction are absorbed in the same manner as in the first embodiment, Breakage of the writing core 370 exposed from the tip of the base 352 is avoided (see FIGS. 5B and 5C).

  Also by this embodiment as described above, the same effect as that of the first embodiment can be obtained. Further, since the chuck 343 is moved forward by the inertial force of the weight body 390 by swinging the shaft cylinder 310 back and forth, the writing core 370 can be quickly fed out without performing a knocking operation.

  Next, a mechanical pencil 400 according to a fourth embodiment of the present invention will be described with reference to FIG.

  FIG. 6 is a schematic longitudinal sectional view of the mechanical pencil 400 according to the fourth embodiment of the present invention. FIG. 6A shows the mechanical pencil 400 when no writing pressure is applied to the writing core 470. 6B is a schematic longitudinal sectional view of the mechanical pencil 400 when a writing pressure perpendicular to the axial direction is applied to the writing core 470. FIG. (C) is a schematic longitudinal sectional view of the mechanical pencil 400 when a writing pressure perpendicular to the axial direction and a writing pressure in the axial direction are applied to the writing core 470.

  Unlike the second embodiment, the mechanical pencil 400 according to the present embodiment includes a swing-out type core feeding unit 440. Specifically, the core feeding unit 440 according to the present embodiment includes a polypropylene core pipe 441 extending in the axial direction of the shaft tube 410 inside the shaft tube 410, and an outer periphery fixed to the front end portion of the core pipe 441. A connector 449 made of polyacetal resin having a protrusion formed on the surface, a chuck 443 fixed to the front end of the connector 449, a fastening ring 442 externally fitted to the front region of the chuck 443, and the connector 449 in the rearward direction in the axial direction A return spring 444 that urges (rightward in FIG. 6), and a knock portion made of ABS resin that is attached to the rear end of the core pipe 441 and presses the core pipe 441 forward in the axial direction (leftward in FIG. 6). 448, and a weight body 490 disposed so as to be loosely fitted on the outer periphery of the core pipe 441 in a space formed between the shaft tube 410 and the core pipe 441. The has. As the weight body 490, the same structure as the weight body 390 of 3rd Embodiment can be employ | adopted.

  Similarly to the third embodiment, the weight body 490 of this embodiment also moves back and forth within the space when the shaft tube 410 is swung back and forth (in the left-right direction in FIG. 6). The front part is in contact with the protrusion 449a of the connector 449. When the connector 449 comes into contact with the weight body 490, the connector 449 is advanced in the axial direction by the inertial force of the weight body 490.

  Further, the rear shaft 420 of the present embodiment has a protruding portion 426a on the inner peripheral surface of the rear region, and a weight body 490 is disposed between the protruding portion 426a and the connector 449. The inner diameter of the rear shaft 420 is smaller than the outer diameter of the weight body 490 at the protruding portion 426a.

  Similarly to the third embodiment, the crown 426 of the present embodiment also has a step portion 426b on the inner peripheral surface, and the inner diameter of the step portion 426b in the axial direction rearward is that of the step portion 426. It is larger than the inner diameter at the front in the axial direction. A flange portion 448c is formed on the outer periphery of the holder portion 448b of the knock portion 448, and a compressible spring 448d that can be expanded and contracted is disposed between the flange portion 448c and the step portion 426b of the head crown 426. Yes.

  Other configurations are the same as those of the mechanical pencil 200 of the second embodiment. In FIG. 6A to FIG. 6C, components similar to those in the second embodiment are denoted by substantially the same reference numerals, and detailed description thereof is omitted.

  In the mechanical pencil 400 of the present embodiment, when a high writing pressure is applied to the writing core 470, the component perpendicular to the axial direction of the writing pressure and the component in the axial direction are respectively the second embodiment. Breakage of the writing core 470 that is absorbed in the same manner and exposed from the tip of the base 452 is avoided (see FIGS. 6B and 6C).

  Further, as the shaft tube 410 is swung back and forth, the writing core 470 is exposed (paid out) from the tip of the base 452 in the same manner as in the third embodiment.

  According to the present embodiment as described above, the same effect as that of the second embodiment can be obtained. Furthermore, since the chuck 443 is moved forward by the inertial force of the weight body 490 by swinging the shaft tube 410 back and forth, the writing core can be quickly delivered without performing a knock operation.

10 Shaft cylinder 20 Rear shaft 21 Guide member 21a Small diameter part 21b Large diameter part 22 Male thread part 23 Engaged part 24 Female thread part 25 Step part 26 Head crown 26a Projection part 30 Front shaft 31 Engagement part 32 Press part 40 Core extension Unit 41 Core pipe 42 Fastening ring 43 Chuck 44 Return spring 45 Outer cylinder 46 Projection 47 Flange 48 Knock 48a Sleeve 48b Holder 50 Cap unit 51 Base member 52 Base 53 Flange 54 Projection 55 Coil spring 56 Tapered surface 57 Contact step 60 Coil spring 70 Writing core 80 Eraser 81 Knob 100 Mechanical pencil 200 Mechanical pencil 210 Shaft cylinder 220 Rear shaft 226 Head crown 226a Sleeve portion 230 Front shaft 232 Pressing portion 233 Protruding portion 240 Core feeding unit 241 Core pipe 242 Tightening ring 243 chuck 44 Return spring 245 Outer cylinder 246 Protruding part 247 Flange part 248 Knock part 248a Sleeve part 248b Holder part 250 Base unit 251 Base member 252 Base 253 Flange part 254 Projecting part 255 Coil spring 256 Tapered surface 257 Contacting step part 260 Coil spring 270 Writing core 280 Eraser 281 Knob 300 Mechanical pencil 310 Shaft cylinder 320 Rear shaft 321 Guide member 321a Small diameter part 321b Large diameter part 322 Male thread part 323 Engaged part 324 Female thread part 325 Step part 326 Head crown 326a Projection part 326b Step part 330 Front shaft 331 Engaging portion 332 Pressing portion 340 Core feeding unit 341 Core pipe 342 Fastening ring 343 Chuck 344 Return spring 345 Outer cylinder 346 Protruding portion 347 Flange portion 348 Knock portion 348a Probe part 348b Holder part 348c Flange part 348d Spring 349 Connector 349a Projection part 350 Cap unit 351 Base member 352 Base part 353 Flange part 354 Projection part 355 Coil spring 356 Tapered surface 357 Abutting step part 360 Coil spring 370 Writing core 380 Eraser 381 Knob 390 Weight body 400 Mechanical pencil 410 Shaft cylinder 420 Rear shaft 426 Head crown 426a Protruding portion 430 Front shaft 432 Pressing portion 433 Protruding portion 440 Core feeding unit 441 Core pipe 442 Fastening ring 443 Chuck 444 Return spring 445 Outer cylinder 446 Protruding portion 447 Flange 448 Knock portion 448a Sleeve portion 448b Holder portion 448c Flange portion 448d Spring 449 Connector 449a Projection portion 450 Cap unit 451 Base member 45 2 Base 453 Flange 454 Projection 455 Coil Spring 456 Tapered Surface 457 Contact Step 460 Coil Spring 470 Writing Core 480 Eraser 481 Knob 490 Weight Body

Claims (7)

A shaft having a rear shaft and a front shaft connected to the rear shaft and tiltable with respect to the rear shaft;
A lead feeding unit for feeding the writing lead supported in the shaft tube;
A base having a passage for a writing core therein and supported in the front end region of the lead feeding unit so as to be relatively movable in the axial direction;
A first overhang provided on the outer peripheral surface of the front end region of the lead feeding unit;
A first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base;
A stretchable first elastic body disposed in a compressed state between the first projecting portion and the first projecting portion;
A second protrusion provided on the inner peripheral surface of the rear region of the rear shaft;
A second overhanging portion provided on the outer circumferential surface in the axial direction of the second projecting portion of the core feeding unit;
A stretchable second elastic body disposed in a compressed state between the second projecting portion and the second overhang portion;
With
The base has a pressed portion in the rear region,
The front shaft has a pressing portion in the front region,
At least one of the pressed portion and the pressing portion is a tapered surface that gradually decreases in diameter toward the rear in the axial direction,
Before the front shaft tilts with respect to the rear shaft, the pressing portion and the pressed portion are in contact with each other, and when the front shaft tilts with respect to the rear shaft, the pressing portion The mechanical pencil is characterized in that the part moves the pressed part relative to the front end region of the lead feeding unit in the axial direction. A shaft having a rear shaft, and a front shaft connected to the rear shaft and capable of bending deformation;
A lead feeding unit for feeding the writing lead supported in the shaft tube;
A base having a passage for a writing core therein and supported in the front end region of the lead feeding unit so as to be relatively movable in the axial direction;
A first overhang provided on the outer peripheral surface of the front end region of the lead feeding unit;
A first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base;
A stretchable first elastic body disposed in a compressed state between the first projecting portion and the first projecting portion;
A second protrusion provided on the inner peripheral surface of the rear region of the rear shaft;
A second overhanging portion provided on the outer circumferential surface in the axial direction of the second projecting portion of the core feeding unit;
A stretchable second elastic body disposed in a compressed state between the second projecting portion and the second overhang portion;
With
The front shaft is made of a material having a Young's modulus of any value between 0.01 GPa and 10 GPa,
The base has a pressed portion in the rear region,
The front shaft has a pressing portion in the front region,
At least one of the pressed portion and the pressing portion is a tapered surface that gradually decreases in diameter toward the rear in the axial direction,
Before the front shaft is bent and deformed, the pressing portion and the pressed portion are in contact with each other, and when the front shaft is bent and deformed, the pressing portion extends the pressed portion from the core. A mechanical pencil characterized by being moved relative to the front end region of the unit in the axial direction. A shaft having a rear shaft and a front shaft that is disposed in front of the rear shaft and is tiltable with respect to the rear shaft;
A lead feeding unit for feeding out a writing lead, which is arranged in the shaft cylinder and fixed to the inner peripheral surface of the rear shaft;
A base having a passage for a writing core therein and supported in the front end region of the lead feeding unit so as to be relatively movable in the axial direction;
A first overhang provided on the outer peripheral surface of the front end region of the lead feeding unit;
A first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base;
A stretchable first elastic body disposed in a compressed state between the first projecting portion and the first projecting portion;
A second protrusion provided on the inner peripheral surface of the rear region of the front shaft;
A second overhanging portion provided on the outer circumferential surface in the axial direction of the second projecting portion of the core feeding unit;
A stretchable second elastic body disposed in a compressed state between the second projecting portion and the second overhang portion;
With
The base has a pressed portion in the rear region,
The front shaft has a pressing portion in the front region,
At least one of the pressed portion and the pressing portion is a tapered surface that gradually decreases in diameter toward the rear in the axial direction,
Before the front shaft tilts with respect to the rear shaft, the pressing portion and the pressed portion are in contact with each other, and when the front shaft tilts with respect to the rear shaft, the pressing portion The mechanical pencil is characterized in that the part moves the pressed part relative to the front end region of the lead feeding unit in the axial direction. A shaft having a rear shaft, and a front shaft disposed in front of the rear shaft and capable of bending deformation;
A lead feeding unit for feeding out a writing lead, which is arranged in the shaft cylinder and fixed to the inner peripheral surface of the rear shaft;
A base having a passage for a writing core therein and supported in the front end region of the lead feeding unit so as to be relatively movable in the axial direction;
A first overhang provided on the outer peripheral surface of the front end region of the lead feeding unit;
A first projecting portion provided on an inner peripheral surface axially rearward of the first projecting portion of the base;
A stretchable first elastic body disposed in a compressed state between the first projecting portion and the first projecting portion;
A second protrusion provided on the inner peripheral surface of the rear region of the front shaft;
A second overhanging portion provided on the outer circumferential surface in the axial direction of the second projecting portion of the core feeding unit;
A stretchable second elastic body disposed in a compressed state between the second projecting portion and the second overhang portion;
With
The front shaft is made of a material having a Young's modulus of any value between 0.01 GPa and 10 GPa,
The base has a pressed portion in the rear region,
The front shaft has a pressing portion in the front region,
At least one of the pressed portion and the pressing portion is a tapered surface that gradually decreases in diameter toward the rear in the axial direction,
Before the front shaft is bent and deformed, the pressing portion and the pressed portion are in contact with each other, and when the front shaft is bent and deformed, the pressing portion extends the pressed portion from the core. A mechanical pencil characterized by being moved relative to the front end region of the unit in the axial direction. The core feeding unit includes a core pipe that extends in an axial direction of the shaft cylinder inside the shaft cylinder, a connector that is fixed to a front end portion of the core pipe and has a protrusion formed on an outer peripheral surface thereof, A chuck fixed to the front end, a tightening ring externally fitted to the front region of the chuck, a return spring that urges the connector axially rearward, and a core pipe attached to the rear end of the core pipe. A knock portion for pressing forward in the axial direction, and a weight body disposed so as to be loosely fitted to the outer periphery of the core pipe in a space formed between the shaft tube and the core pipe. And
The weight body is configured to move back and forth in the space when the shaft tube is swung back and forth, and abuts on the protrusion of the connector in front. The mechanical pencil according to any one of 1 to 4. The pressed portion of the base is the tapered surface, and the tapered surface has any angle between 20 ° and 60 ° with respect to the axial direction of the shaft cylinder,
The first elastic body is a first coil spring;
The load required to move the pressed portion relative to the core feeding unit in the axial direction against the urging force of the first coil spring is any value between 0.5N and 3N. The mechanical pencil according to any one of claims 1 to 5, wherein the mechanical pencil is provided. The second elastic body is a second coil spring;
The load required to move the lead feeding unit relative to the rear shaft in the axial rearward direction against the urging force of the second coil spring is any value between 1.5N and 4.5N. The mechanical pencil according to claim 6, wherein

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