JP2010120204A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which enables inhibiting of one-sided wear of a lead apex by automatically rotating the lead under specified pressure to the lead apex during writing and also, writing as the lead apex is always sharp, without rotating a barrel during writing. <P>SOLUTION: This mechanical pencil comprises the following components: a barrel 1 into which a tip 2 is fitted, a lead pipe 3 inserted into the barrel 1, a lead chuck 8 through which a chuck ring 9 is loosely inserted in such a state that the lead chuck 8 is connected with the apex of the lead pipe 3, a sleeve 10 which is arranged movably in the axial direction as the sleeve 10 straddles the apex part of the lead pipe 3 and the lead chuck 8, a stopper 13 which regulates the movement of the sleeve 10 in the axial direction within a specified range, a chuck spring 14 which urges the chuck ring 9 in the direction where the lead chuck 8 is fastened, and a cushioning spring 15 which urges the sleeve 10 in the forward moving direction. In addition, a lead rotating mechanism 20 is provided which rotates the lead 18 projecting from the tip 2 as the lead 18 is retained by the lead chuck 8 under a specified writing pressure. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a mechanical pencil capable of rotating a core with a predetermined pressure against a brush tip.

  A conventional mechanical pencil includes a shaft tube, a tip attached to the tip of the shaft tube, a core pipe inserted into the shaft tube, a lead chuck connected to the tip of the core pipe, and the lead A chuck ring loosely fitted in the chuck, a sleeve that is fitted in the tip and restricts axial movement of the chuck ring, and a chuck spring that biases the chuck ring in the lead chuck tightening direction via the sleeve And a cushion stopper fixed to the rear part of the tip, and a cushion spring interposed between the front end of the cushion stopper and the rear end of the sleeve (for example, Patent Document 1) reference).

  In such a conventional mechanical pencil, by knocking the rear end knock part of the core pipe, the core protrudes from the tip and is used for writing, but the core at the time of writing is firmly held by the lead chuck. It does not rotate in the circumferential direction.

Japanese Utility Model Publication No. 58-37678 (right column on page 1 and FIG. 1)

  With conventional mechanical pencils, the writing core is held in a fixed position regardless of the pressure and does not rotate in the circumferential direction, so if you write on the paper while holding the shaft cylinder in the same direction, the tip will rub. As the area of the lead tip increases and the lead tip area increases, a so-called lead tip reduction occurs, and there is a problem that writing cannot be performed with the tip sharply pointed unless the shaft tube is rotated during writing.

  The present invention has been made to solve the above-described problems. When writing, the lead can be automatically rotated with a predetermined pressure against the lead to prevent the tip from being reduced. An object of the present invention is to provide a mechanical pencil that can be written with the tip of the core always sharp without turning the shaft cylinder.

  Another object of the present invention is to provide a mechanical pencil capable of realizing a core rotation mechanism that automatically rotates the core with a simple structure.

  Furthermore, an object of the present invention is to provide a mechanical pencil that can increase the amount of rotation of the lead.

  Furthermore, an object of the present invention is to provide a mechanical pencil that can prevent a rotation failure of the core rotation system due to the resistance of the end portion of the cushion spring.

  Furthermore, an object of the present invention is to provide a mechanical pencil that can be protruded by rotating the lead to the writing position by the cushion pressure even when the lead is not at the writing position.

  The mechanical pencil according to the present invention includes a shaft tube, a tip attached to the tip of the shaft tube, a core pipe inserted into the shaft tube, a lead chuck connected to the tip of the core pipe, A chuck ring loosely fitted to the lead chuck, a sleeve arranged to be movable in the axial direction across the tip of the core pipe and the lead chuck, and abutting the rear end of the chuck ring; A lead pencil comprising: a stopper for restricting axial movement within a certain range; a chuck spring for biasing the chuck ring in a lead chuck tightening direction; and a cushion spring for biasing the sleeve in a forward direction. A lead rotating mechanism is provided that rotates the lead held from the tip and projecting from the tip with a predetermined pressure.

  The lead rotation mechanism of the mechanical pencil according to the present invention includes a first cam surface formed on the inner surface of the sleeve receiver, a second cam surface formed on the tip surface of the stopper and facing the first cam surface, The cam projection is formed on the outer surface of the sleeve and disposed between the first cam surface and the second cam surface, and the cam projection acts as an urging force of the cushion spring when the lead moves backward by pressing. The core is rotated by a predetermined angle through a sleeve at a predetermined angle through sliding contact with the second cam surface, and the cam projection is urged by the urging force of the cushion spring when the pressure is released. And the core is rotated at a predetermined angle in the same direction as the rotation by a predetermined pressing.

  The mechanical pencil lead rotating mechanism according to the present invention is characterized in that the sleeve is rotated by applying a pressure of 250 g to 650 g or more to the lead held by the lead chuck so that the lead is rotated. .

  The mechanical pencil according to the present invention is characterized in that a bearing is disposed between the rear end of the sleeve and the cushion spring.

  In the mechanical pencil according to the present invention, the core and the core holding guide are moved back together by a predetermined pressure (cushion pressure) against the tip of the core holding guide provided in the tip, and the cam projection of the sleeve is the second one. The lead holding guide stays in the tip when the pressure is released, the lead holding guide stays in the tip, the cam projection moves to the first cam face, and the lead comes into contact with the first spring surface. The lead (of the length of the cushion) is drawn out from the tip of the.

  According to the mechanical pencil of the present invention, the lead rotation mechanism operates with a predetermined pressure (cushion pressure) during writing to automatically rotate the lead, so that the tip of the lead can be prevented from being reduced. The effect is that you can always write in a sharp state.

  According to the mechanical pencil of the present invention, the first cam surface is formed on the inner surface of the sleeve receiver, the second cam surface is formed on the tip surface of the stopper, and the cam projection is formed on the outer surface of the sleeve. There is an effect that the core at the time of writing can be reliably rotated by pressing by the core rotation mechanism having a simple structure.

  Furthermore, according to the mechanical pencil of the present invention, the sleeve rotates by applying a pressure of 250 g to 650 g or more to the core held by the lead chuck, so that the rotation amount of the rotating core can be increased accordingly. This is effective in sharpening the core tip efficiently.

  Furthermore, according to the mechanical pencil of the present invention, the bearing is disposed between the rear end of the sleeve and the cushion spring, so that the cushion winding resistance of the cushion spring with respect to the sleeve can be prevented by the bearing. Further, there is an effect that the rotation of the sleeve by the urging force of the cushion spring and the rotation of the core accompanying this can be smoothly performed.

  Further, according to the mechanical pencil of the present invention, the predetermined pressing against the tip of the lead holding guide causes the lead and the lead holding guide to move back together, and the cam projection of the sleeve rotates in sliding contact with the second cam surface. When the pressure is released, the lead holding guide stays in the tip, and the cam protrusion moves in sliding contact with the first cam surface and rotates, and the rotated lead is pushed from the tip of the lead holding guide by the urging force of the cushion spring. Since the lead of the lead is drawn out, for example, the lead holding guide protrudes even when the tip of the lead worn by repeated writing does not protrude from the lead holding guide, so that the cushion pressure (press) is applied to the lead holding guide. By applying, the tip of the lead comes out from the tip of the lead holding guide while the lead rotates. For this reason, there is an effect that writing can be continued without interruption.

Embodiment 1 FIG.
1A is a sectional view showing a mechanical pencil according to Embodiment 1 of the present invention, FIG. 1B is an enlarged sectional view showing a tip unit in FIG. 1, and FIG. 2A is FIG. FIG. 2B is a cross-sectional view of FIG. 2A, and FIG. 3 is a cross-sectional view of the tip tool.
The mechanical pencil according to the first embodiment includes a shaft tube 1, a tip 2 attached to the tip of the shaft tube 1, a core pipe 3 inserted into the shaft tube 1, and a tip of the core pipe 3. The core feeding mechanism 4 provided in the section is provided, and the detailed structure will be described below.

  In the first embodiment, the shaft cylinder 1 is divided into a front shaft 1A and a rear shaft 1B, and the rear portion of the front shaft 1A and the front portion of the rear shaft 1B are detachably connected. The tip tool 2 is detachably screwed to the tip of the tip shaft 1A. A gripper 5 made of an elastic material is fitted on the outer peripheral surface of the front shaft 1A. A clip 6 is attached to the rear end of the rear shaft 1B by a tail crown 7.

  The lead feeding mechanism 4 includes a lead chuck 8 connected to the tip of the lead pipe 3, a chuck ring 9 loosely fitted on the lead chuck 8, and a tip of the lead pipe 3 provided in the axial direction. A movable and rotatable sleeve 10, a stopper 13 provided on the outer front portion of the core pipe 3 and on the outer rear portion of the sleeve 10, and connected and fixed to the rear portion of the tip 2, and inside the sleeve 10. A chuck spring 14 that is disposed and biases the chuck ring 9 in the tightening direction of the lead chuck 8 via the sleeve 10 and a sleeve 10 that is disposed inside the stopper 13 and biases the sleeve 10 in the forward direction via the bearing 12. The structure includes a cushion spring 15.

  A lead holding guide 16 through which the lead 18 is inserted is inserted into the tip center hole of the tip tool 2 so as to be movable in the direction of protruding from the tip of the tip tool 2. A slider 17 is provided behind the lead holding guide 16 so as to be movable in the axial direction.

  As a means for connecting the tip 2 and the stopper 13, as shown in FIG. 2 (A), an axial locking hole 2a is provided at the rear of the tip 2 and a locking projection 13a is provided on the stopper 13. The locking projection 13a is fitted into the locking hole 2a and locked. The bearing 12 is disposed between the rear end of the sleeve 10 and the front end of the cushion spring 15, and prevents rotation of the cushion spring 15 with respect to the sleeve 10 to prevent rotation of the core rotation system including the sleeve 10. It is intended not to cause any trouble.

  In the lead feeding mechanism 4 having such a structure, the lead 18 accommodated in the lead pipe 3 and sandwiched by the lead chuck 8 and protruding from the lead holding guide 16 via the slider 17 is pressed with a predetermined pressure. A core rotation mechanism 20 is provided for rotation.

  In the first embodiment, the lead rotating mechanism 20 is formed on the first cam surface 21 formed on the inner surface of the tip tool 2 with the tip tool 2 as a sleeve receiver, and on the front end surface of the stopper 13. The second cam surface 22 that is spaced apart from the first cam surface 21 and the outer peripheral surface of the intermediate portion of the sleeve 10 and is disposed between the first cam surface 21 and the second cam surface 22. The cam projection 23 is formed.

FIG. 4 illustrates a related configuration of the first cam surface 21 formed on the inner surface of the tip 2, the second cam surface 22 formed on the distal end surface of the stopper 13, and the cam protrusion 23 of the sleeve 10. FIG.
Here, the first cam surface 21 and the second cam surface 22 are each formed of a cam groove formed in a continuous V shape, and the first cam surface 21 and the second cam surface 22 are respectively As shown in FIG. 4, the cam grooves are displaced so that the cam grooves of the second cam surface 22 face the bottom of the cam grooves of the first cam surface 21.
On the other hand, the cam projection 23 is formed in a planar triangular shape having inclined surfaces that selectively come into sliding contact with the cam groove inclined surfaces of the first cam surface 21 and the second cam surface 22.

  The lead rotating mechanism 20 applies a cushion pressure (pressing) of 250 g to 650 g or more, which is equal to or higher than the normal pressing, to the lead 18 held by the lead chuck 8, whereby the sleeve 10 rotates. The wick 18 is configured to rotate.

  The lead rotating mechanism 20 configured as described above is configured so that the cam projection 23 is in sliding contact with the second cam surface 22 against the urging force of the cushion spring 15 when the lead 18 is moved backward by a predetermined pressure. 10, the core 18 is rotated at a predetermined angle in a predetermined direction, and the cam protrusion 23 is brought into sliding contact with the first cam surface 21 by the urging force of the cushion spring 15 to release the pressure and press the core 18. It is made to rotate at a predetermined angle in the same direction as the rotation direction by.

  An eraser receiving base 26 for holding the eraser 25 is detachably attached to the rear end portion of the core pipe 3, and an eraser cover 27 is detachably fitted to the eraser receiving base 26.

Next, the operation will be described. FIG. 5 is an operation explanatory diagram.
When the eraser cover 27 at the rear end of the core pipe 3 is knocked in a state where the core holding guide 16 and the core 18 are retracted into the tip tool 3, the core 18 held by the lead chuck 8 is moved forward by the core pipe 3 moving forward. Then, the slider 17 and the lead holding guide 16 both advance, the lead holding guide 16 protrudes from the tip tool 3, and the lead 18 protrudes from the lead holding guide 16 so that writing is possible (see FIG. 5A).

  After writing in this state, when the core 18 is used up to the tip of the core holding guide 16 and a predetermined pressure is applied to the core holding guide 16 that houses the core 18, the core pressure is applied by the cushion pressure acting on the core 18. 18 and the lead chuck 8 and the sleeve 10 against the urging force of the cushion spring 15 by a predetermined distance (the distance of the cam protrusion 23 moving in the axial direction between the first cam surface 21 and the second cam surface 22). Move backwards. This moving distance (cushion cost) is preferably about 1 mm. As the sleeve 10 moves backward, the inclined surface of the cam projection 23 integrated with the sleeve 10 comes into sliding contact with one inclined surface of the cam groove of the cam surface (second cam surface) 22 of the stopper 13 (FIG. 5). (See (B)), the cam projection 23 is guided along the one-side inclined surface, whereby the sleeve 10 rotates in a predetermined direction at a predetermined angle. The amount of rotation of the sleeve 10 at this time corresponds to the length of the one-side inclined surface of the cam groove forming the second cam surface 22.

  Since the chuck ring 9 tightening the lead chuck 8 is pressed against the tip of the sleeve 10 rotating in this manner, the lead chuck 8 and the core pipe 3 are integrated with the sleeve 10 via the chuck ring 9. Rotate. Therefore, the core 18 held by the lead chuck 8 rotates together with the sleeve 10.

  When the pressing of the core 18 is released, the sleeve 10 moves forward by the urging force of the cushion spring 15, and the cam projection 23 of the sleeve 10 moves to the cam surface (first cam surface) 21 on the inner surface of the tip 3. Thus, the sleeve 10 is further slidably contacted with the inclined surface on one side of the cam groove of the cam surface 21, whereby the sleeve 10 is further rotated in the same direction as the rotation direction by the pressing as described above. Rotates integrally with the sleeve 10 (see FIG. 5C).

  According to the first embodiment described above, as the lead rotating mechanism 20, the first cam surface 21 is formed on the inner surface of the tip 2, and the second cam surface 22 is formed on the distal end surface of the stopper 13. In addition, the cam projection 23 is formed on the outer surface of the sleeve 10 and the cam projection 23 is simply disposed between the first cam surface 21 and the second cam surface 22. By applying a predetermined pressure to the core 18 projected from the tip of the tip 2 by the rear end knock of the pipe 3, the sleeve 10 and the lead chuck 8 are operated by the cam action of the core rotating mechanism 20 by the backward movement of the sleeve 10. And the core 18 can be automatically rotated by a predetermined angle. In addition, even when the tip of the lead is released, the lead 18 can be further automatically rotated by the cam action of the lead rotating mechanism 20 by the sleeve 10 moving forward by the urging force of the cushion spring 15.

  In this way, the lead 18 automatically rotates intermittently in the same direction by a predetermined press and release, so that the tip of the lead can be prevented from being reduced, and writing can be performed with the tip always pointed. There is an effect that can be done.

  In addition, the sleeve 10 can be intermittently rotated at an angle of 45 degrees by 1/8 by the cam action of the lead rotating mechanism 20 by applying a cushion pressure (pressing) of 250 g to 650 g or more to the lead 18. The amount of rotation of the rotating core 18 can be increased, whereby the tip of the core can be sharpened efficiently, a cushion margin is secured, and the rotation angle is increased without causing an operation failure in the shaft tube 1. There is an effect that the lead 18 can be smoothly rotated. In this case, if the inclined surfaces of the first cam surface 21 and the second cam surface 22 in the core rotation mechanism 20 are formed long, the rotation amount of the sleeve 10 and the core 18 is further increased to, for example, 60 degrees or more. There is an effect that can be done.

  Furthermore, according to the first embodiment, since the lead holding guide 16 through which the lead 18 is inserted is movably attached in the direction in which the lead 18 protrudes and retracts, for example, the lead point worn by repeated writing is the lead holding guide. Since the lead holding guide 16 protrudes from the tip 2 even when it does not protrude from the tip 16, by applying cushion pressure (pressing) to the lead holding guide 16, the lead 18 rotates from the lead holding guide 16 while the lead 18 rotates. Is effective. For this reason, there is an effect that writing can be continued without interruption.

  Furthermore, the bearing 12 is disposed between the rear end of the sleeve 10 and the front end of the cushion spring 15 so that the front end of the cushion spring 15 does not directly contact the rear end of the sleeve 10. Thus, the rotation of the sleeve 10 is not hindered by the resistance of the end winding, and therefore, the core rotation system including the sleeve 10 can be smoothly rotated by the cam action of the core rotation mechanism 20. .

Embodiment 2. FIG.
6A is a cross-sectional view showing a mechanical pencil according to Embodiment 2 of the present invention, FIG. 6B is a cross-sectional view showing a front shaft unit in FIG. 6A, and FIGS. ) Is a cross-sectional view showing the operation of FIG. 6A, and the same parts as those in FIGS.
In the first embodiment, the leading tool 2 is used as a sleeve receiver, and the lead feeding mechanism 4 is incorporated into the leading tool 2 to form a unit, and the first cam surface 21 of the lead rotating mechanism 20 is formed on the inner surface of the leading tool 2. However, in the second embodiment, the lead shaft 1A of the barrel 1 is used as a sleeve receiver and the lead feeding mechanism 4 is incorporated into the tip tool 2 to form a unit as shown in FIG. The first cam surface 21A is formed on the inner surface of 1A, and the other structure is the same as that of the first embodiment.

Thus, even when the first cam surface 21A is formed on the inner surface of the front shaft 1A, the same effects as those of the first embodiment can be obtained.
Further, in the second embodiment, since the lead feeding mechanism 4 is unitized on the front shaft 1A, when the front tool 2 is removed from the front shaft 1A, as shown in FIG. Further, since the chuck ring 9 protrudes from the tip of the front shaft 1A, there is an effect that it is possible to easily remove the broken core when the core is clogged, clean the inside of the lead chuck 8, and the like.

Embodiment 3 FIG.
FIG. 8 is a cross-sectional view showing the tip of the mechanical pencil according to the third embodiment in relation to the sleeve and the stopper. The same parts as those in FIGS.
In the third embodiment, a multi-face engaging portion 28 and an inward rib 29 are formed on the intermediate inner peripheral surface of the front shaft 1A in the second embodiment so as to be separated from each other in the axial direction, and on the outer peripheral surface of the stopper 13. Is formed by separating a multi-faceted engagement portion 30 to be aligned with the engagement portion 28 and an outward rib 31 to be engaged with the inward rib 29 in the axial direction.

  According to the front shaft 1A and the stopper 13 having such a structure, the engagement portion 30 of the stopper 13 is fitted and aligned with the engagement portion 28 of the front shaft 1A, whereby the first shaft formed on the inner surface of the front shaft 1A. The cam surface 21A and the second cam surface 22 formed on the distal end surface of the stopper 13 can be positioned at a predetermined position by interposing the cam protrusion 23 of the sleeve 10 between the cam surfaces 21A and 22. There is an effect. Further, since the engaging portions 28 and 30 are each formed in a polyhedral shape, the effect of preventing the stopper 13 from rotating can also be obtained by the engagement between the engaging portions 28 and 30. Further, at the engagement position between the engagement portions 28 and 30, the inward rib 29 of the front shaft 1A and the outward rib 31 of the stopper 13 are engaged, whereby the stopper 13 is moved to a predetermined position in the front shaft 1A. There is an effect that it can be fixed securely.

Embodiment 4 FIG.
FIG. 9 is a sectional view showing a rear end knock portion of the mechanical pencil according to the fourth embodiment of the present invention.
The mechanical pencil of the fourth embodiment has a knock portion structure in which the rotation of the core pipe 3 that rotates integrally with the sleeve 10 by the cam action of the core rotation mechanism 20 is not hindered by the eraser cradle 26 that also serves as a knock member. It is.

  That is, in the mechanical pencil illustrated in FIG. 9, the cylindrical leg portion 26a formed on the eraser cradle 26 is slidably inserted into the cylindrical knock guide 33 provided inside the rear portion of the rear shaft 1B. A stopper 26b is formed at the tip of the leg 26a to be engaged with and disengaged from the tip of the knock guide 33, and a return spring 32 is interposed between the knock guide 33 and the eraser cradle 26. The rear portion of the core pipe 3 is inserted into the leg portion 26a of the eraser cradle 26 so as to be freely rotatable so that the rotation of the core pipe 3 is not interfered by the eraser cradle (knock member) 26. .

  According to the mechanical pencil of the fourth embodiment having such a structure, the rotation of the core pipe 3 is not hindered by the eraser cradle 26. Therefore, the core rotation mechanism in the mechanical pencil of the first or second embodiment. There is an effect that the cam 10 can smoothly rotate the sleeve 10, the core pipe 3, the core feed mechanism 4, and the core 18 interlocked with the sleeve 10.

  In each of the above embodiments, the shaft cylinder 1 is divided into the front shaft 1A and the rear shaft 1B. However, even if the shaft tube 1 is a single shaft, the same effect can be obtained. It is done. Further, the core holding guide 16 in the first and second embodiments may be integrally fixed with the shaft tube 1 or the tip tool 2. Furthermore, in the first embodiment, the tip 2 is a sleeve receiver, and in the second embodiment, the front shaft 1A is a sleeve receiver. However, when the shaft cylinder 1 has a middle shaft, the middle shaft may be a sleeve receiver. .

1A is a sectional view showing a mechanical pencil according to Embodiment 1 of the present invention, and FIG. 1B is an enlarged sectional view showing a tip unit in FIG. 2A is a plan view showing a connection structure between the tip and the stopper in FIG. 1, and FIG. 2B is a cross-sectional view of FIG. It is sectional drawing of a tip. FIG. 5 is a schematic development view for explaining a related configuration of a first cam surface formed on an inner surface of a tip, a second cam surface formed on a tip end surface of a stopper, and a cam projection formed on a sleeve. . FIG. 5A to FIG. 5C are operation explanatory diagrams. It is. 6A is a cross-sectional view showing a mechanical pencil according to Embodiment 2 of the present invention, and FIG. 6B is a cross-sectional view showing a front shaft unit in FIG. 6A. FIGS. 7A to 7C are cross-sectional views showing the operation of FIG. It is sectional drawing which shows the front axis | shaft of the mechanical pencil by Embodiment 3 of this invention in relation to a sleeve and a stopper. FIG. 10 is a cross-sectional view showing a rear end knock portion of a mechanical pencil according to a fourth embodiment of the present invention.

Explanation of symbols

1 shaft cylinder 1A front shaft 1B rear shaft 2 tip 2a locking hole 3 core pipe 4 core feeding mechanism 5 gripper 6 clip 7 tail crown 8 lead chuck 9 chuck ring 10 sleeve 12 bearing 13 stopper 13a locking projection 14 chuck spring 15 Cushion spring 16 Core holding guide 17 Slider 18 Core 20 Core rotation mechanism 21, 21A First cam surface 22 Second cam surface 23 Cam projection 25 Eraser 26 Eraser cradle 26a Leg portion 26b Retaining portion 27 Eraser cover 28 Engagement Part 29 inward rib 30 engaging part 31 outward rib 32 return spring 33 knock guide

Claims (5)

  A shaft tube, a tip attached to the tip of the shaft tube, a core pipe inserted into the shaft tube, a lead chuck connected to the tip of the core pipe, and loosely fitted to the lead chuck A chuck ring, a sleeve that is arranged to be movable in the axial direction across the tip of the core pipe and the lead chuck, and a sleeve that contacts the rear end of the chuck ring, and the axial movement of the sleeve is restricted to a certain range. A mechanical pencil comprising: a stopper that biases the chuck ring in a lead chuck tightening direction; and a cushion spring that biases the sleeve in a forward direction. A mechanical pencil comprising a lead rotating mechanism for rotating a protruding lead with a predetermined pressure.   The core rotation mechanism includes a first cam surface formed on the inner surface of the sleeve receiver, a second cam surface formed on the tip surface of the stopper and facing the first cam surface, and an outer surface of the sleeve. The cam projection is disposed between the first cam surface and the second cam surface, and the cam projection resists the urging force of the cushion spring when the lead moves backward by a predetermined pressure. The core is rotated at a predetermined angle in a predetermined direction through the sleeve by slidingly contacting the cam surface of the second cam surface, and the cam projection is shifted to the first cam surface by the urging force of the cushion spring when the pressure is released. 2. The mechanical pencil according to claim 1, wherein the lead is rotated at a predetermined angle in the same direction as that when rotating by a predetermined pressure.   3. The lead rotating mechanism according to claim 1, wherein the lead is rotated by applying a pressure of 250 g to 650 g or more to the lead held by the lead chuck to rotate the sleeve. The mechanical pencil described in 1.   The mechanical pencil according to any one of claims 1 to 3, wherein a bearing is disposed between the rear end of the sleeve and the cushion spring.   The core and the core holding guide are retracted in conjunction with a predetermined press against the tip of the core holding guide provided in the tip, and the cam projection of the sleeve rotates in sliding contact with the second cam surface. The guide stays in the tip, the cam projection moves to the first cam surface, rotates in sliding contact, and the rotated lead is fed out from the tip of the lead holding guide by a biasing force of the cushion spring. The mechanical pencil according to any one of claims 1 to 4, characterized in that:

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