JP2023015868A - writing instrument - Google Patents

Abstract

To provide a writing instrument capable of fitting a cap precisely into a barrel.SOLUTION: A mechanical pencil 1 including a barrel 6 and a cap 70 in which a positioning projection part 6a is formed at one side and a positioning recessed part 70b is formed at the other side on an outer peripheral surface of the barrel and an inner peripheral surface of the cap; when the barrel 6 is tried to be fitted into the cap 70 in a state where the positioning projection part 6a and the positioning recessed part 70b are not aligned along an axial direction, the mechanical pencil is constituted so that the positioning projection part 6a and the positioning recessed part 70b are fitted by a suction force due to a magnetic force working between the barrel 6 and the cap 70 in cooperation of the positioning projection part 6a with the positioning recessed part 70b while rotating the barrel 6 or the cap 70 around a central axis to fit the barrel 6 and the cap 70.SELECTED DRAWING: Figure 21

Description

The present invention relates to writing instruments.

A writing instrument having a cap for protecting the writing part is known (for example, Patent Document 1).

The cap is fitted to the barrel for the purpose of protecting the writing portion from damage due to physical contact or the like and preventing drying of ink in the writing portion. Fitting between the barrel and the cap is generally performed in a snap-fitting fashion by allowing projections formed on the inner peripheral surface of the cap to climb over projections formed on the outer peripheral surface of the barrel. The user can recognize that the fitting is securely performed by the sense of touch and hearing when the fitting is snapped.

JP 2013-139135 A

Depending on the height or shape of the projection on the barrel or the cap, the force required to fit the cap may be too strong, and children and the elderly may not be able to fit the cap properly. In addition, when fitting the cap, it is necessary to press the cap strongly against the barrel. There is a risk that the outer peripheral surface of the barrel may be damaged by the edge of the barrel. Furthermore, when attempting to attach identification marks, letters, patterns, etc., or designs or characteristic shapes to the outer surfaces of both the barrel and the cap, the barrel and the cap must be properly aligned in the direction of rotation about the central axis. There is a need.

SUMMARY OF THE INVENTION An object of the present invention is to provide a writing instrument in which a cap can be accurately fitted to a barrel.

According to one aspect of the present invention, a barrel and a cap are provided, and one of the outer peripheral surface of the barrel and the inner peripheral surface of the cap is formed with a positioning protrusion and the other is formed with a positioning recess. If the shaft cylinder and the cap are to be fitted in a state where the positioning protrusions and the positioning recesses are not aligned along the axial direction, the attractive force due to the magnetic force acting between the shaft cylinder and the cap will cause , the positioning protrusion and the positioning recess cooperate to rotate the shaft cylinder or the cap about the central axis, and the positioning protrusion and the positioning recess are fitted together, and the shaft cylinder and the cap are fitted. A writing instrument is provided that is configured to perform the

The positioning protrusion and the positioning recess may have portions complementary to each other. A plurality of the positioning protrusions and the positioning recesses may be provided at equal intervals along the circumferential direction. The barrel may be configured such that the cap can be fitted to the front end portion of the barrel by magnetic attraction force. The barrel may be configured such that the cap can be fitted to the rear end portion of the barrel by magnetic attraction force.

ADVANTAGE OF THE INVENTION According to the aspect of this invention, there exists a common effect of providing the writing instrument which can fit a cap correctly with respect to a barrel.

FIG. 1 is a longitudinal sectional view of a mechanical pencil according to an embodiment of the invention. FIG. 2 is a perspective view of a mechanical pencil. FIG. 3 is an enlarged sectional view of the front half of the mechanical pencil. FIG. 4 is an enlarged sectional view of the rear half of the mechanical pencil. FIG. 5 is a perspective view explaining the internal structure of the mechanical pencil. FIG. 6 is an exploded perspective view of the clutch mechanism. FIG. 7 is an enlarged cross-sectional view of the rotary drive mechanism. 8A and 8B are schematic diagrams for explaining the rotational drive of the rotor of the rotational drive mechanism. FIG. 9 is a schematic diagram illustrating rotation driving of the rotor subsequent to FIG. FIG. 10 is a perspective view of a dial cam member. FIG. 11 is a perspective view of a rail cam member. FIG. 12 is another perspective view of the rail cam member; FIG. 13 is a perspective view of the combined dial cam member and rail cam member; FIG. 14 is another perspective view of the combined dial cam member and rail cam member; FIG. 15 is a schematic diagram showing the surface of the feeding cam. FIG. 16 is a perspective view of an input clutch cam. FIG. 17 is a perspective view of an output clutch cam. FIG. 18 is an enlarged perspective view illustrating cams of an input clutch cam and an output clutch cam. FIG. 19 is a schematic diagram illustrating the operation of a clutch mechanism that cooperates with the rotary drive mechanism. FIG. 20 is a longitudinal sectional view of the lead feeding member. FIG. 21 is an enlarged cross-sectional view of the mechanical pencil for explaining the feeding of the writing lead. FIG. 22 is an enlarged perspective view of the cap. FIG. 23 is an enlarged perspective view of the barrel. FIG. 24 is a perspective view of a holding chuck; FIG. 25 is a vertical cross-sectional view of the holding chuck.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Corresponding elements are provided with common reference numerals throughout the drawings.

1 is a longitudinal sectional view of a mechanical pencil 1 according to an embodiment of the present invention, FIG. 2 is a perspective view of the mechanical pencil 1, and FIG. 3 is an enlarged sectional view of the front half of the mechanical pencil 1, 4 is an enlarged cross-sectional view of the rear half of the mechanical pencil 1, FIG. 5 is a perspective view illustrating the internal structure of the mechanical pencil 1, and FIG. 6 is an exploded perspective view of the clutch mechanism 60. As shown in FIG.

A mechanical pencil 1 has a front barrel 2, a rear barrel 3 screwed onto the outer peripheral surface of the rear end portion of the front barrel 2, and a tip member 4 screwed onto the outer peripheral surface of the front end portion of the front barrel 2. there is The front shaft 2 and the rear shaft 3 constitute a barrel 6 . Note that the shaft tube 6 may include the tip member 4 as well. As will be described later, the mechanical pencil 1 is constructed such that the writing lead 7 protrudes from the tip of the slider 9 . In this specification, in the axial direction of the mechanical pencil 1, the writing lead 7 side is defined as the "front" side, and the side opposite to the writing lead 7 side is defined as the "rear" side.

Referring to FIG. 3, a slider 9 is arranged inside the front end portion of the barrel 6 so as to be slidable in the axial direction and rotatable around the axis. The slider 9 is formed in a cylindrical shape whose outer diameter tapers forward in steps. A flange portion 9 a is provided on the outer peripheral surface of the rear end portion of the slider 9 . The writing lead 7 is guided by the slider 9 and can protrude from the tip of the slider 9 . Inside the slider 9, a holding chuck 10 having a through hole 10a formed in the center is arranged. The through-hole 10a of the holding chuck 10 is in sliding contact with the outer peripheral surface of the writing lead 7 and acts to temporarily hold the writing lead 7. As shown in FIG.

A dial cam member 50, which is a cylindrical first cam member, and a rail cam member 52, which is an annular second cam member, are arranged in alignment in the axial direction on the outer peripheral surface of the slider 9. It is A substantially cylindrical grip portion 8 is provided on the front end portion of the tip member 4 and the outer peripheral surface of the dial cam member 50 . The tip of the slider 9 protrudes from the hole at the front end of the dial cam member 50 . A ball chuck 11 for gripping the writing lead 7, specifically a fastener 13, is fitted to the inner peripheral surface of the rear end portion of the slider 9. As shown in FIG.

The ball chuck 11 has a cylindrical fastener 13 , a chuck main body 14 arranged in the fastener 13 , a cylindrical chuck holder 15 , and a plurality of balls 16 . ing. A tapered surface that widens forward is formed on the inner peripheral surface of the fastener 13 . The chuck main body 14 has a through hole for the writing lead 7 formed along the central axis, and the front end of the chuck main body 14 is divided into a plurality of parts along the axial direction. A rear end portion of the chuck body portion 14 is held by a chuck holding portion 15 . The chuck body portion 14 and the chuck holding portion 15 are axially movable with respect to the fastener 13 . The plurality of balls 16 are arranged between the inner peripheral surface of the fastener 13 and the outer peripheral surface of the chuck body portion 14 .

When writing pressure is applied to the writing lead 7 , the writing lead 7 is gripped by the chuck body 14 because the chuck main body 14 abuts against the tapered surface inside the cylindrical fastener 13 together with the ball 16 . This prevents the writing lead 7 from retreating. On the other hand, when a force is exerted to draw the writing lead 7 forward, the chuck main body 14 is not affected by the fastener 13, so the writing lead 7 can be drawn forward without resistance. That is, the ball chuck 11 acts to allow the writing lead 7 to move forward and prevent it from retreating.

A coil spring 17 is arranged to surround the chuck main body 14 . A rear end portion of the coil spring 17 is fitted to the outer surface of the chuck body portion 14 , and a front end portion of the coil spring 17 is supported by a stepped portion formed on the inner peripheral surface of the fastener 13 . The coil spring 17 urges the chuck main body 14 rearward, and as a result, the ball chuck 11 can maintain the state of gripping the writing lead 7 . A cam contact spring 18, which is a coil spring, is arranged so as to surround the fastener 13. As shown in FIG. A cam contact spring 18 biases the slider 9 forward. The front end portion of the lead case 19 is fitted to the outer peripheral surface of the rear end portion of the chuck holding portion 15 . The lead case 19 is formed in a cylindrical shape and accommodates the writing lead 7 therein.

An input clutch cam 61 of a clutch mechanism 60 to be described later is connected to the ball chuck 11 . That is, the input clutch cam 61 is formed in a cylindrical shape, and the outer peripheral surface of the rear end portion of the fastener 13 of the ball chuck 11 is fitted to the inner peripheral surface of the front end portion of the input clutch cam 61 . . The inner peripheral surface of the rear end portion of the input clutch cam 61 is fitted with the outer peripheral surface of the front end portion of the cylindrical relay member 12 . As will be described later with reference to FIGS. 5 and 6, the clutch mechanism 60 has a projecting abutment 65c projecting forward. The abutment 65c is urged forward through the slider 9 by a cam abutment spring 18. As shown in FIG. Therefore, the slider 9, the ball chuck 11, the relay member 12, the input clutch cam 61 and the abutment 65c are integrally movable within the shaft cylinder 6 in the axial direction. A rear end portion of the relay member 12 is connected to a rotation drive mechanism 30 which will be described later.

Referring to FIG. 4 , a knock rod 20 as a knock portion is provided at the rear end portion of the barrel 6 so as to be movable back and forth with respect to the barrel 6 . The knock bar 20 is urged rearward by a coil spring 21 . A partition wall portion 20a having a supply hole for the writing lead 7 is formed near the rear end portion of the knock rod 20. As shown in FIG. An eraser 22 is detachably mounted inside the rear end portion of the knock rod 20 . A knock cover 23 is detachably attached to the outer peripheral surface of the rear end portion of the knock rod 20 to protect the eraser 22 from dirt and the like. The knock bar 20 is fitted on the outer peripheral surface of the rear end portion of the lead case 19 .

The lead case 19 moves forward by performing a knocking operation to press the knock rod 20 or the knock cover 23 forward. As a result, the chuck main body 14 is pushed forward through the chuck holding portion 15 . Along with this, the writing lead 7 gripped by the chuck main body 14 also advances, acting to extend the writing lead 7 from the slider 9 .

When the pressure by the knocking operation is released, the biasing force of the coil spring 21 causes the knock rod 20 to retreat and return to its original position. At this time, the chuck main body 14 retreats due to the biasing force of the coil spring 17 . On the other hand, since the writing lead 7 is held by the holding chuck 10 arranged in the slider 9 , the writing lead 7 is pulled out from the chuck body 14 without resistance as the action of the ball chuck 11 . As a result, since the writing lead 7 is extended from the slider 9, the writing lead 7 can be extended by a predetermined amount each time the knocking operation is repeated. When the knock rod 20 is maintained in the forward state by the knocking operation, the chuck main body 14 protrudes from the fastener 13 and the grip of the writing lead 7 is released. In this state, the writing lead 7 that has been drawn out from the slider 9 can be pushed back with a fingertip or the like.

FIG. 7 is an enlarged cross-sectional view of the rotation drive mechanism 30. As shown in FIG. The rotary drive mechanism 30 is arranged in the internal space of the rear axle 3 . The rotation drive mechanism 30 is connected to the rear end of the relay member 12 . A shaft spring 31 is arranged between the rear end surface of the front shaft 2 and the front end surface of the rotary drive mechanism 30 to bias the rotary drive mechanism 30 rearward. The rearward movement of the rotary drive mechanism 30 due to the biasing force of the shaft spring 31 is restricted by the contact of the rear end surface of the rotary drive mechanism 30 with a step provided on the inner surface of the shaft cylinder 6 . The lead case 19 passes through the interior of the relay member 12 and the rotary drive mechanism 30 and is separated from the rotary drive mechanism 30 .

The rotation drive mechanism 30 includes a cylindrical rotor 40, a cylindrical first cam forming member 41, and a cylindrical second cam forming member. It has a lower cam forming member 42 , a cylindrical cylinder member 43 , a cylindrical torque canceller 44 , and a coiled cushion spring 45 . The rotary drive mechanism 30 is unitized by integrating these members.

The outer peripheral surface of the rear end portion of the relay member 12 is fitted to the inner peripheral surface of the front end portion of the rotor 40 . Near the front end of the rotor 40, there is a flange-like portion with a slightly larger diameter. A cam surface 40b is formed.

The upper cam forming member 41 rotatably surrounds the rotor 40 behind the first cam surface 40 a of the rotor 40 . The lower cam forming member 42 is fitted to the outer peripheral surface of the front end portion of the upper cam forming member 41 . A first fixed cam surface 41a, which is a first fixed cam surface, is formed on the front end surface of the upper cam forming member 41 facing the first cam surface 40a of the rotor 40. As shown in FIG. A second fixed cam surface 42a, which is a second fixed cam surface, is formed on the inner surface of the front end portion of the lower cam forming member 42 facing the second cam surface 40b of the rotor 40. As shown in FIG.

A cylinder member 43 formed in a cylindrical shape is fitted to the outer peripheral surface of the rear end portion of the upper cam forming member 41 . A rear end portion of the cylinder member 43 is formed with an insertion hole 43a through which the lead case 19 can be inserted. In the cylinder member 43, a torque canceller 44 formed in a cylindrical shape and movable in the axial direction is arranged. A cushion spring 45 is arranged between the inner surface of the front end of the torque canceller 44 and the inner surface of the rear end of the cylinder member 43 . The cushion spring 45 urges the rotor 40 forward via the torque canceller 44 .

Here, the relay member 12 transmits the backward and forward movement (cushion movement) of the writing lead 7 based on the writing movement to the rotation drive mechanism 30, that is, the rotor 40, and the rotor in the rotation drive mechanism 30 caused by the cushion movement. The rotary motion of 40 is transmitted to the ball chuck 11 holding the writing lead 7 . Therefore, the writing lead 7 held by the ball chuck 11 also rotates.

Except when writing with the mechanical pencil 1 , that is, when writing pressure is not applied to the writing lead 7 , the rotor 40 is positioned forward by the biasing force of the cushion spring 45 via the torque canceller 44 . Therefore, the second cam surface 40b of the rotor 40 contacts and meshes with the second fixed cam surface 42a. When writing with the mechanical pencil 1, that is, when writing pressure is applied to the writing lead 7, the ball chuck 11 retreats against the biasing force of the cushion spring 45, and the rotor 40 also moves accordingly. fall back. Therefore, the first cam surface 40a of the rotor 40 contacts and meshes with the first fixed cam surface 41a.

8A and 8B are schematic diagrams for sequentially explaining the rotational driving action of the rotor 40 of the mechanical pencil 1 of FIG. 1, and FIG. 9 is a schematic diagram for explaining the rotational driving action of the rotor 40 following FIG. is. In FIGS. 8 and 9, a first cam surface 40a continuously saw-toothed along the circumferential direction is formed in an annular shape on the rear end surface, which is the upper surface of the rotor 40. A second cam surface 40b having a sawtooth shape is formed in an annular shape on the front end surface, which is the lower surface, similarly in the circumferential direction.

A first fixed cam surface 41a is also formed continuously along the circumferential direction on the annular end surface of the upper cam forming member 41 facing the first cam surface 40a of the rotor 40. A second fixed cam surface 42a is also formed continuously along the circumferential direction in a sawtooth shape on the annular end surface of the lower cam forming member 42 facing the second cam surface 40b. A first cam surface 40 a and a second cam surface 40 b formed on the rotor 40 , a first fixed cam surface 41 a formed on the upper cam forming member 41 and a second cam surface 41 a formed on the lower cam forming member 42 . The cam surfaces of the two fixed cam surfaces 42a are formed to have substantially the same pitch.

FIG. 8A shows the relationship between the rotor 40, the upper cam forming member 41 and the lower cam forming member 42 when no writing pressure is applied to the writing lead 7. FIG. In this state, the second cam surface 40 b formed on the rotor 40 meshes with the second fixed cam surface 42 a of the lower cam forming member 42 by the biasing force of the cushion spring 45 . At this time, the first cam surface 40a of the rotor 40 and the first fixed cam surface 41a of the upper cam forming member 41 are shifted in the axial direction by half a phase (half a pitch) with respect to one tooth of the cam. is set to

FIG. 8B shows an initial state in which writing pressure is applied to the writing lead 7 for writing with the mechanical pencil 1 . In this state, the rotor 40 retracts by contracting the cushion spring 45 as the ball chuck 11 retracts. As a result, the rotor 40 moves toward the first fixed cam surface 41 a of the upper cam forming member 41 .

Next, FIG. 8(C) shows a state in which writing pressure is further applied to the writing lead 7, and the rotor 40 contacts the first fixed cam surface 41a of the upper cam forming member 41 and retreats. In this state, the first cam surface 40 a of the rotor 40 meshes with the first fixed cam surface 41 a of the upper cam forming member 41 . Thereby, the rotor 40 is rotationally driven corresponding to a half phase (half pitch) of one tooth of the first cam surface 40a.

8 and 9 are used to indicate the amount of rotational movement of the rotor 40. As shown in FIG. In the state shown in FIG. 8(C), the second cam surface 40b of the rotor 40 and the second fixed cam surface 42a of the lower cam forming member 42 are in a half phase with respect to one tooth of the cam in the axial direction. half pitch).

Next, FIG. 9(D) shows an initial state in which writing with the mechanical pencil 1 is finished and the writing pressure on the writing lead 7 is released. In this case, the rotor 40 moves forward due to the biasing force of the cushion spring 45 . As a result, the rotor 40 moves toward the lower cam forming member 42 .

Next, FIG. 9(E) shows a state in which the rotor 40 advances by contacting the first fixed cam surface 41a of the upper cam forming member 41 by the biasing force of the cushion spring 45. As shown in FIG. In this case, the second cam surface 40b of the rotor 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42. As shown in FIG. As a result, the rotor 40 is again driven to rotate corresponding to the half phase (half pitch) of one tooth of the second cam surface 40b.

Therefore, as indicated by the triangular mark drawn in the center of the rotor 40, the rotor 40 moves along the first cam surface as the rotor 40 receives the writing pressure and reciprocates in the axial direction, that is, moves back and forth. 40a and the second cam surface 40b are driven to rotate corresponding to one tooth (one pitch), and the writing lead 7 gripped by the ball chuck 11 is similarly driven to rotate. Therefore, when the rotor 40 moves back and forth once in the axial direction due to writing, the rotor 40 undergoes a rotational motion corresponding to one tooth of the cam, and by repeating this, the writing lead 7 is sequentially rotated. Therefore, it is possible to prevent uneven wear of the writing lead 7 as the writing progresses, and to prevent a large change in the thickness and density of the drawn line.

In short, the rotary drive mechanism has a first cam forming member and a second cam forming member, the rotor is formed in an annular shape, and the first cam surface and the second cam surface are formed on one end surface and the other axial end surface of the rotor. A first fixed cam surface and a second fixed cam surface formed on the first cam forming member and the second cam forming member are arranged so as to face the first cam surface and the second cam surface, respectively. , the retraction of the ball chuck due to the writing pressure causes the first cam surface of the rotor to contact and mesh with the first fixed cam surface, and the release of the writing pressure causes the second cam surface of the rotor to engage with the second fixed cam surface. In a state in which the first cam surface of the rotor is meshed with the first fixed cam surface, the second cam surface of the rotor and the second fixed cam surface are axially aligned with each other. is set in a phase-shifted relationship with respect to one tooth of the cam, and in a state in which the second cam surface of the rotor is meshed with the second fixed cam surface, the first cam surface of the rotor and the first fixed cam surface are set in an axially out-of-phase relationship with respect to one tooth of the cam.

The torque canceller 44 that receives the biasing force of the cushion spring 45 and pushes the rotor 40 forward generates a slip between the front end surface of the torque canceller 44 and the rear end surface of the rotor 40, and the rotational motion of the rotor 40 is prevented. It prevents transmission to the cushion spring 45 . That is, the torque canceller 44 prevents the rotational motion of the rotor 40 from being transmitted to the cushion spring 45, thereby generating torsion return (torque) of the cushion spring 45 that hinders the rotational motion of the rotor 40. prevent this from happening.

As described above, the mechanical pencil 1 has the ball chuck 11 and the rotor 40, and by moving the ball chuck 11 back and forth to release and grip the writing lead 7, the writing lead 7 can be extended forward. The ball chuck 11 is held in the barrel 6 so as to be rotatable around the central axis while gripping the writing lead 7, and the writing pressure of the writing lead 7 passes through the ball chuck 11. The forward and backward movement of the rotor 40 rotates the rotor 40 , and the rotational motion of the rotor 40 is transmitted to the writing lead 7 via the ball chuck 11 .

The lead feeding mechanism and the feeding amount adjusting mechanism will be described with reference to FIGS. 10 to 14. FIG. The lead feeding mechanism receives the rotational driving force of the rotor 40 of the rotary drive mechanism 30 and acts to feed the writing lead 7 from the slider 9 .

10 is a perspective view of the dial cam member 50. FIG. 10, the dial cam member 50 is arranged so that the upper side is the rear side of the mechanical pencil 1. As shown in FIG. The dial cam member 50 is a member formed in a cylindrical shape, and includes a cam body 50a, a flange portion 50b formed on the outer peripheral surface of the cam body 50a, and a fitting projection 50c formed on the rear end surface of the flange portion 50b. and a dial cam 51 formed on the rear end surface of the cam body 50a. The dial cam 51 has a flat first annular cam surface 51a positioned further forward and perpendicular to the central axis, and a flat second annular cam surface 51b positioned further rearward and perpendicular to the central axis. there is Both ends of the first annular cam surface 51a and the second annular cam surface 51b are connected by a vertical wall 51c.

11 is a perspective view of the rail cam member 52, and FIG. 12 is another perspective view of the rail cam member 52. FIG. 11 and 12, the rail cam member 52 is arranged so that the upper side is the rear side of the mechanical pencil 1. As shown in FIG. The rail cam member 52 is an annular member. An adjustment recess 52a is formed in the front end surface of the rail cam member 52. As shown in FIG. A plurality of fitting recesses 52b are formed on the bottom surface of the adjustment recess 52a and are arranged in parallel at regular intervals along the circumferential direction.

A rail cam 53 is formed on the rear end surface of the rail cam member 52 . The rail cam 53 includes a first flat annular cam surface 53a positioned further forward and perpendicular to the central axis, a second flat annular cam surface 53b positioned further rearward and perpendicular to the central axis, and a first annular cam. A slope 53c, which is a slope-shaped annular cam surface, is provided so as to rise along the circumferential direction so as to connect one ends of the surface 53a and the second annular cam surface 53b. The other ends of the first annular cam surface 53a and the second annular cam surface 53b are connected by a vertical wall 53d.

13 is a perspective view of the combined dial cam member 50 and rail cam member 52, and FIG. 14 is another perspective view of the combined dial cam member 50 and rail cam member 52. FIG. 13 and 14, the dial cam member 50 and the rail cam member 52 are arranged so that the upper side is the rear side of the mechanical pencil 1. As shown in FIG. The annular rail cam member 52 is inserted into the rear end portion of the cam main body 50a of the dial cam member 50 and engaged by the flange portion 50b to be combined. That is, the front end surface of the rail cam member 52 contacts the rear end surface of the flange portion 50 b of the dial cam member 50 . At this time, the fitting projection 50 c provided on the flange portion 50 b of the dial cam member 50 fits into one of the fitting recesses 52 b of the adjustment recesses 52 a of the rail cam member 52 . The rail cam member 52 is arranged radially outside the dial cam member 50 .

When the dial cam member 50 and the rail cam member 52 are combined, the dial cam 51 of the dial cam member 50 is arranged near the rail cam 53 of the rail cam member 52 . The dial cam 51 and the rail cam 53 thereby cooperate to form a series of, or annular, payout cam surfaces 54 in the circumferential direction.

As shown in FIG. 3, the dial cam member 50 and the rail cam member 52 are arranged outside the slider 9 in a combined state. A part of the dial cam member 50 and the rail cam member 52 are covered with the proboscis member 4 and the grip portion 8 on the outer peripheral surface. The gripping portion 8 is engaged with the outer peripheral surface of the dial cam member 50 . Therefore, it is rotatable around the central axis together with the dial cam member 50 . A coil spring 56 is arranged between the inner surface of the front end portion of the tip member 4 and the flange portion 50 b of the dial cam member 50 . Further, the abutment 65c urged forward by the cam abutment spring 18 through the slider 9 maintains a state of abutment against the delivery cam surface 54. As shown in FIG. The outer peripheral surface of the rail cam member 52 is engaged with the inner peripheral surface of the tip member 4 , and the rotation of the rail cam member 52 with respect to the tip member 4 and thus the shaft tube 6 is restricted.

The shape of the feed cam surface 54 can be changed by relatively rotating the dial cam member 50 and the rail cam member 52 about the central axis. Specifically, the user rotates the dial cam member 50 around the central axis by rotating the grip portion 8 with the other hand while gripping the barrel 6 with one hand. Since the rail cam member 52 is engaged with the barrel 6 , the dial cam member 50 rotates about the central axis relative to the rail cam member 52 . The rotation of the dial cam member 50 with respect to the rail cam member 52 is performed stepwise so that the fitting projections 50c of the dial cam member 50 move between the adjacent fitting recesses 52b of the corresponding rail cam members 52 to fit. will be Therefore, the rotation of the dial cam member 50 about the central axis with respect to the rail cam member 52 is performed stepwise within the range of the adjustment recess 52a of the rail cam member 52 in which the fitting projection 50c of the dial cam member 50 can move. The relative position between the dial cam 51 of the dial cam member 50 and the rail cam 53 of the rail cam member 52 changes according to the position of the fitting recess 52b of the rail cam member 52 into which the fitting projection 50c of the dial cam member 50 is fitted. As a result, the shape of the feeding cam surface 54 can be changed. The dial cam member 50 is urged against the rail cam member 52 by the coil spring 56, and a click feeling is obtained when the dial cam member 50 rotates in stages with respect to the rail cam member 52.例文帳に追加

Next, with reference to FIG. 15, the drawing of the writing lead 7 by the drawing cam surface 54 will be described. FIG. 15 is a schematic diagram showing the feeding cam surface 54. As shown in FIG. FIG. 15 shows the positional relationship between the dial cam member 50 and the rail cam member 52, and is a circumferential development of a cylindrical surface around the central axis including the feed cam surface 54. As shown in FIG. In FIG. 15 , the upper side is the rear side of the mechanical pencil 1 .

Referring to FIG. 15, the dial cam member 50 is aligned with the rail cam member 52 so that the vertical wall 51c of the dial cam 51 and the inclined surface 53c of the rail cam 53 are radially overlapped. . In FIG. 15 , the line (surface) positioned more rearward, that is, higher than in the drawing, of the dial cam 51 and the rail cam 53 constitutes the feed cam surface 54 . That is, the second annular cam surface 51b of the dial cam 51 and the second annular cam surface 53b and slope 53c of the rail cam 53 cooperate to form the extension cam surface . In addition, the height (height difference) of the step 55 (height difference) in the axial direction formed by the second annular cam surface 51b of the dial cam 51 and the inclined surface 53c of the rail cam 53 on the feed cam surface 54 is defined as the step height H and

When the dial cam member 50 and the rail cam member 52 are relatively rotated around the central axis so that the vertical wall 51c of the dial cam 51 is arranged on the first annular cam surface 53a side of the rail cam 53, the step height H becomes higher. On the other hand, when the dial cam member 50 and the rail cam member 52 are relatively rotated around the central axis so that the vertical wall 51c of the dial cam 51 is arranged on the side opposite to the first annular cam surface 53a of the rail cam 53, , the step height H becomes lower.

The rotor 40 of the rotary drive mechanism 30 gradually rotates the abutment 65c based on the cushioning action of the writing lead 7, as will be described later. That is, when the tip of the slider 9 is viewed first, the abutment 65c rotates to the right around the central axis. Due to this rotational motion, the abutment 65c biased forward by the cam abutment spring 18 moves in the circumferential direction while cooperating with the feed cam surface 54. As shown in FIG. That is, since the abutment 65c moves from right to left in FIG.

When the abutment 65 c reaches the step 55 , it is pressed by the biasing force of the cam contact spring 18 and drops into the step 55 . That is, the abutment 65c moves further forward from the second annular cam surface 51b of the dial cam 51 by the step height H of the step 55 . At this time, as the abutment 65c moves forward, the slider 9 and the holding chuck 10 arranged inside the slider 9 also move forward. As a result, the writing lead 7 held by the holding chuck 10 is pulled out from the ball chuck 11 and relatively extended from the tip of the slider 9 by the step height H. Therefore, the amount of the writing lead 7 that is drawn out, ie, the amount of drawing out, is equal to the height H of the step.

By the above operation, the writing lead 7 can be drawn out from the slider 9 each time the abutment 65c makes one turn along the drawing cam surface 54. As shown in FIG. By repeating this operation, the writing lead 7 is worn out in accordance with the writing action, and the writing lead 7 is successively drawn out.

In short, in the lead feeding mechanism, the abutment 65c moves along the feeding cam surface 54 according to the rotation of the rotor 40, and the slider 9 advances when the abutment 65c falls into the step 55 of the feeding cam surface 54. The writing core 7 held by the holding chuck 10 is pulled out from the ball chuck 11 by the operation. By using the step 55 of the feeding cam surface 54 in the lead feeding mechanism, the rotational driving force of the rotor 40 in the rotary drive mechanism 30 can be converted into the feeding operation of the writing lead 7 . A configuration that forms a height difference on the feed cam surface 54 is generically called a "drop".

The mechanical pencil 1 is configured such that the writing lead 7 held by the ball chuck 11 is also driven to rotate by receiving the rotational driving force of the rotor 40 in the rotation drive mechanism 30 . Therefore, it is possible to prevent uneven wear of the writing lead 7 as writing progresses, and as a result, it is possible to prevent a large change in the thickness and density of the drawn line. In short, the rotation drive mechanism 30 has a rotor 40, and receives an axial backward movement due to the writing pressure received by the writing lead 7 gripped by the ball chuck 11 and an axial forward movement due to the release of the writing pressure. Rotor 40 is rotated in one direction.

In the extension amount adjusting mechanism, as described above, the step height H of the step 55 on the extension cam surface 54 can be changed simply by relatively rotating the dial cam member 50 and the rail cam member 52 about the central axis. can. Therefore, it is possible to more easily and accurately adjust the amount of drawing of the writing lead 7 by the lead drawing mechanism.

If the degree of wear of the writing lead 7 due to differences in the writing pressure and the hardness of the writing lead 7 used by the user is adjusted so that the extension amount of the writing lead 7 substantially matches, writing can be performed. The amount of protrusion of the writing lead 7 from the slider 9 can always be kept constant despite the presence of the slider. As a result, with the mechanical pencil 1, it is possible to continue writing for a long time with a single knock operation. It is preferable to configure the dial cam 51 or the rail cam 53 so that the step 55 having a step height H corresponding to a length exceeding the degree of wear of the writing lead 7 normally assumed is formed. As a result, it is possible to set the feeding amount of the writing lead 7 according to the preferences of all users.

In the embodiment described above, the dial cam member 50 was a cylindrical member as the first cam member, but it may be an annular member. Further, although the rail cam member 52 is an annular member as the second cam member, it may be a cylindrical member. The first cam member may be provided with the rail cam 53 and the second cam member may be provided with the dial cam 51 . That is, the annular or tubular first cam member and the annular or tubular second cam member arranged radially outwardly of the first cam member cooperate to form the feeding cam surface. good too. Further, the step height of the step may be adjusted by moving the first cam member and the second cam member relatively back and forth, that is, by separating them in the axial direction.

The rail cam member 52 may be constructed integrally with the dial cam member 50 so that the dial cam member constitutes only a single extension cam surface 54 . In this case, although the extension amount cannot be adjusted as described above, the number of parts can be reduced and the cost can be reduced. A plurality of dial cam members with different step heights H may be provided to adjust the amount of extension. In this case, the user may select and replace the dial cam member with which the user can realize the optimum extension amount.

Next, the clutch mechanism 60 will be described with reference to FIGS. 3, 5, 6 and 16-19. The clutch mechanism 60 acts to convert the rotary motion of the rotor 40 in the rotary drive mechanism 30 as an input into the rotary motion of the abutment 65c as an output. The clutch mechanism 60 has an input clutch cam 61 as an input member, an output clutch cam 62 as an output member, a transmission cam 64 and a feed cam 65 . Moreover, the mechanical pencil 1 further has a clutch cam holder 66 .

16 is a perspective view of the input clutch cam 61, FIG. 17 is a perspective view of the output clutch cam 62, and FIG. 18 is an enlarged perspective view illustrating cams of the input clutch cam 61 and the output clutch cam 62. be. The input clutch cam 61 is arranged so that its upper side is the rear side of the mechanical pencil 1 in FIG. 16, and the output clutch cam 62 is arranged so that its upper side is the rear side of the mechanical pencil 1 in FIG. . In FIG. 18 , the upper side is the rear side of the mechanical pencil 1 .

The input clutch cam 61 is a cylindrical member, and one cam protrusion 61a is provided on an annular rear end surface 61b forming an input cam surface. A flange portion 61 c is provided on the outer peripheral surface of the rear end portion of the input clutch cam 61 .

The output clutch cam 62 is arranged behind the input clutch cam 61 . The output clutch cam 62 is a cylindrical member, and a flange portion 62a is provided on the outer peripheral surface of the output clutch cam 62 near the front end thereof. An annular front end surface of the output clutch cam 62 is provided with a clutch cam surface 63 which is an output cam surface. The clutch cam surface 63 is arranged to face the cam protrusion 61 a of the input clutch cam 61 . The clutch cam surface 63 is composed of a plurality of peaks 63a and a plurality of valleys 63b having a flat bottom surface provided between the adjacent peaks 63a.

Referring to FIG. 18, the cam projection 61a of the input clutch cam 61 and the peak portion 63a of the output clutch cam 62 have substantially the same shape. The cam protrusion 61a of the input clutch cam 61 has a first engaging surface 61aa substantially perpendicular to the rear end surface 61b and a first inclined surface 61ab. Similarly, the peak portion 63a of the output clutch cam 62 has a second engaging surface 63aa substantially perpendicular to the bottom surface of the valley portion 63b and a second inclined surface 63ab. As will be described later, in the operation of the clutch mechanism 60, the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62 are engaged, so that the input clutch cam 61 and the output clutch A cam 62 cooperates.

Referring to FIGS. 3, 5 and 6, the outer peripheral surface of the front end of the output clutch cam 62 is fitted with the rear end of the transmission cam 64 . The transmission cam 64 is inserted until the rear end surface of the transmission cam 64 contacts the flange portion 62 a of the output clutch cam 62 . The transmission cam 64 is formed in a cylindrical shape, and the front end surface thereof is provided with first engaging projections 64a extending forward and arranged at regular intervals along the circumferential direction. A first engaging wall 64b extending along the axial direction is provided on a side surface of the first engaging projection 64a in the circumferential direction. An annular protrusion 64 c is provided on the inner peripheral surface of the transmission cam 64 .

The input clutch cam 61 is disposed within the transmission cam 64 such that the flange portion 61c is disposed between the clutch cam surface 63 of the output clutch cam 62 and the annular projection 64c of the transmission cam 64. That is, the forward movement of the input clutch cam 61 is restricted by the engagement of the flange portion 61 c with the annular protrusion 64 c of the transmission cam 64 . The retraction of the input clutch cam 61 is restricted by cooperation between the cam protrusion 61 a and the clutch cam surface 63 of the output clutch cam 62 .

An extension cam 65 is arranged in front of the transmission cam 64 . The feeding cam 65 is formed in a cylindrical shape, and the rear end surface thereof is provided with second engaging projections 65a extending rearward and arranged at regular intervals along the circumferential direction. The second engaging projection 65 a has a shape complementary to the first engaging projection 64 a of the transmission cam 64 . A second engaging wall 65b is provided along the axial direction on the side surface of the second engaging projection 65a in the circumferential direction. The front end surface of the feed cam 65 is provided with the above-described one projecting abutment 65c projecting forward. An annular protrusion 65 d is provided on the inner peripheral surface of the front end portion of the feeding cam 65 .

The slider 9 is inserted into the delivery cam 65 from behind, and the flange portion 9a and the annular projection 65d of the delivery cam 65 can be locked. The cam contact spring 18 described above is arranged so that one end thereof engages with the inner surface of the flange portion 9 a of the slider 9 and the other end thereof engages with the front end surface of the input clutch cam 61 . The biasing force of the cam abutting spring 18 biases the slider 9 forward, and the feed cam 65 is biased forward via the biased flange portion 9a of the slider 9 . As a result, the abutment 65c is urged to abut against the delivery cam surface 54 as described above. The feed cam 65 can move integrally with the slider 9 in the axial direction, but can rotate independently around the central axis.

The clutch cam holder 66 is formed in a cylindrical shape and is attached to the inner surface of the shaft tube 6 , specifically the front shaft 2 . The inner peripheral surface of the clutch cam holder 66 is coated with liquid lubricating oil such as grease as a high-viscosity material. The output clutch cam 62 is inserted into the clutch cam holder 66 so that the space between the outer peripheral surface of the output clutch cam 62 and the inner peripheral surface of the clutch cam holder 66 is filled with liquid lubricating oil. As a result, the output clutch cam 62 and the connected transmission cam 64 are loosely held by the clutch cam holder 66, and rapid movement in the axial direction within the barrel 6 caused by gravity or the like is mitigated. The clutch cam holder 66 may be provided integrally with the shaft tube 6 . That is, a viscous fluid that suppresses axial movement of the output member is arranged between the output member and the shaft tube. Since the mechanical pencil 1 has the clutch cam holder 66, it is possible to absorb the influence of dimensional variations and frictional resistance of each part of the clutch mechanism 60. FIG. Note that the clutch cam holder 66 may be omitted.

Referring to FIG. 3 , as described above, the outer peripheral surface of the rear end portion of the fastener 13 of the ball chuck 11 is fitted to the inner peripheral surface of the front end portion of the input clutch cam 61 . The outer peripheral surface of the front end portion of the relay member 12 is fitted to the inner peripheral surface of the rear end portion of the relay member 12 . A rear end portion of the relay member 12 is connected to the rotor 40 (FIG. 4). Therefore, the input clutch cam 61 is rotationally driven by the rotor 40 of the rotational drive mechanism 30 via the relay member 12 . Also, the input clutch cam 61 moves back and forth together with the rotor 40 via the relay member 12 based on the cushioning action of the writing lead 7 . The relay member 12 passes through the insides of the output clutch cam 62 and the transmission cam 64 and is separated from the relay member 12 . Therefore, the rotational motion and forward/backward motion of the relay member 12 are not directly transmitted to the output clutch cam 62 and the transmission cam 64 .

Rotational motion of the input clutch cam 61 is transmitted to the output clutch cam 62 through cooperation between the cam protrusion 61a and the clutch cam surface 63 of the output clutch cam 62, as will be described later with reference to FIG. Rotational motion of the output clutch cam 62 is transmitted to the payout cam 65 via the connected transmission cam 64 . That is, as the transmission cam 64 rotates, the first engagement wall 64b of the first engagement projection 64a engages with the second engagement wall 65b of the second engagement projection 65a in the circumferential direction. Rotational motion is transmitted to the payout cam 65 . As a result, the abutment 65c moves along the drawing cam surface 54 as described above, and the writing lead 7 is drawn out.

19A and 19B are schematic diagrams illustrating the operation of the clutch mechanism 60 that cooperates with the rotary drive mechanism 30. FIG. FIG. 19 shows the positional relationship between the rotor 40, the upper cam forming member 41 and the lower cam forming member 42 in the rotary drive mechanism 30, and the input clutch cam 61 and the output clutch cam 62 in the clutch mechanism 60. It is a circumferential development of a cylindrical surface around the center axis including the surface. In FIG. 19 , the upper side is the rear side of the mechanical pencil 1 . The state of the rotary drive mechanism 30 shown in FIGS. 19A to 19E is the state of the rotary drive mechanism 30 shown in FIGS. 8A to 8C and FIGS. 9D and 9E. correspond respectively to Each of the rotor 40 and the output clutch cam 62 is marked with a triangle to indicate the amount of rotational movement.

FIG. 19A shows the relationship between the rotary drive mechanism 30 and the clutch mechanism 60 when no writing pressure is applied to the writing lead 7. FIG. The rotary drive mechanism 30 corresponds to the state shown in FIG. 8(A). Therefore, the second cam surface 40b of the rotor 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42. As shown in FIG. At this time, the cam protrusion 61a of the input clutch cam 61 and the clutch cam surface 63 of the output clutch cam 62 are separated in the axial direction and are not in contact with each other. The triangle marks attached to each of the rotor 40 and the output clutch cam 62 are arranged on the same straight line in the axial direction.

Next, FIG. 19(B) shows an initial state in which writing pressure is applied to the writing lead 7 . The rotary drive mechanism 30 corresponds to the state shown in FIG. 8(B). Therefore, in this state, the rotor 40 moves toward the upper cam forming member 41 and the input clutch cam 61 approaches the clutch cam surface 63 of the output clutch cam 62 . At this time, the first engagement surface 61aa of the cam protrusion 61a of the input clutch cam 61 and the second engagement surface 63aa (FIG. 18) of the peak portion 63a of the output clutch cam 62 are spaced apart in the circumferential direction. are spaced apart by a distance D1 in the circumferential direction.

Next, FIG. 19(C) shows a state in which writing pressure is further applied to the writing lead 7, and the first cam surface 40a of the rotor 40 meshes with the first fixed cam surface 41a of the upper cam forming member 41. there is The rotary drive mechanism 30 corresponds to the state shown in FIG. 8(C). Therefore, the rotor 40 is rotationally driven corresponding to a half phase (half pitch) of one tooth of the first cam surface 40a. That is, the rotor 40 rotates from the state shown in FIG. 19A by a rotation angle corresponding to the distance L1 of the amount of rotational movement in the circumferential direction. As the rotor 40 is driven to rotate, the cam protrusion 61a of the input clutch cam 61 and the peak portion 63a of the output clutch cam 62 are engaged with each other, and the output clutch cam 62 is driven to rotate via the input clutch cam 61 . As shown in FIG. 19B immediately before this, since the cam protrusion 61a of the input clutch cam 61 and the peak portion 63a of the output clutch cam 62 are spaced apart in the circumferential direction, the rotational movement of the output clutch cam 62 is reduced. The amount is less than the input clutch cam 61 , ie, the rotational travel distance L1 of the rotor 40 . Specifically, the amount of rotational movement of the output clutch cam 62 is the distance L2 obtained by subtracting the distance D1 from the distance L1, so the output clutch cam 62 rotates by the second rotation angle corresponding to the distance L2.

Next, FIG. 19(D) shows an initial state in which the writing pressure on the writing lead 7 is released. The rotary drive mechanism 30 corresponds to the state shown in FIG. 9(D). Therefore, in this state, the rotor 40 is moved toward the lower cam forming member 42 by the biasing force of the cushion spring 45, and the cam protrusion 61a of the input clutch cam 61 is separated from the clutch cam surface 63 of the output clutch cam 62. .

Next, FIG. 19E shows a state in which the second cam surface 40b of the rotor 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42 by the biasing force of the cushion spring 45. As shown in FIG. The rotary drive mechanism 30 corresponds to the state shown in FIG. 9(E). Therefore, the rotor 40 is again driven to rotate corresponding to the half phase (half pitch) of one tooth of the second cam surface 40b. That is, the rotor 40 and the input clutch cam 61 connected to the rotor 40 move from the state shown in FIG. Rotate by the first rotation angle. On the other hand, since the cam projection 61a of the input clutch cam 61 and the peak portion 63a of the output clutch cam 62 are separated in the axial direction, the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 61aa of the output clutch cam 62 It does not engage with the engagement surface 63aa, and therefore the output clutch cam 62 is not rotationally driven. The input clutch cam 61 and the output clutch cam 62 cooperate only on the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62, and cooperate on the other portions. configured not to.

A single axial movement of the rotor 40 caused by writing causes the rotor 40 and the input clutch cam 61 to rotate corresponding to one tooth of the cam of the rotary drive mechanism 30, while the output clutch cam 62 is rotated by one tooth of the cam. less rotational movement than That is, the clutch mechanism 60 rotates the input clutch cam 61 so that when the input clutch cam 61 rotates by the first rotation angle, the output clutch cam 62 rotates by a second rotation angle smaller than the first rotation angle. to the output clutch cam 62. The cam pitch in the clutch mechanism 60 is set smaller than the cam pitch in the rotary drive mechanism 30 . Specifically, the rotation angle (first rotation angle) corresponding to one tooth of the cam of the rotary drive mechanism 30 and the rotation angle (second rotation angle) of the difference between the rotation angle corresponding to one tooth of the cam of the clutch mechanism 60 angle), the output clutch cam 62 is rotationally driven.

For example, the number A of teeth of the rotary drive mechanism 30 such as the first cam surface 40a of the rotor 40 is assumed to be 40, and the number B of teeth of the clutch cam surface 63 of the output clutch cam 62 is assumed to be 46. The number of strokes required for the rotor 40 to rotate once, that is, the number of strokes of writing, is 40 strokes. Since the rotation angle C of the rotor 40 per image is 360/A, 360/40=9 degrees. Since the rotation angle D corresponding to the distance between the adjacent crests 63a of the output clutch cam 62 is 360/D, 360/46=7.83 degrees. Then, as described with reference to FIG. 19, the rotation angle E of the output clutch cam 62 per stroke is CD, so 9-7.83=1.17 degrees. Therefore, the number of strokes required for the output clutch cam 62 to rotate once is 360/1.17=307.7 strokes, in other words, 308 strokes. Expressing this as a speed reduction ratio, 1/(C/E)=1/7.69.

According to the clutch mechanism 60, the number of strokes (for example, 40 strokes) required for the rotor 40 to rotate once is greater than the number of strokes required for the output clutch cam 62 and thus the abutment 65c of the feed cam 65 to rotate once. can be increased (for example, 308 strokes). Further, by adjusting the number of teeth A of the cam of the rotary drive mechanism 30 and/or the number of teeth B of the cam of the clutch mechanism 60, the rotor 40 can be made to make one revolution with an arbitrary number of strokes and the writing lead can be drawn out with an arbitrary number of strokes. can be made

The output clutch cam 62 and the transmission cam 64 may be integrally formed. The output clutch cam 62, the transmission cam 64, and the extension cam 65 may be collectively used as an output member. The slider 9 and the feeding cam 65 may be integrally formed. Although the input clutch cam 61 has one cam projection 61a as an input cam surface, it may have a plurality of cam projections 61a. The input cam surface of the input clutch cam 61 and the clutch cam surface 63, which is the output cam surface of the output clutch cam 62, move in the circumferential direction like the relationship between the first engagement surface 61aa and the second engagement surface 63aa. It may be formed arbitrarily so long as it engages in and does not engage in axial movement. Similarly, the transmission cam 64 and the delivery cam 65 engage for circumferential movement and do not engage for axial movement, like the relationship between the first engagement wall 64b and the second engagement wall 65b. As long as it can be formed arbitrarily.

In the above-described embodiment, meshing clutches, ie, the input clutch cam 61 and the output clutch cam 62 are employed as the input member and the output member, respectively. That is, the clutch mechanism 60 has an input cam surface formed on the input member and an output cam surface formed on the output member facing the input cam surface, and the input cam surface and the output cam surface are formed only during a part of the rotational movement of the rotor. are engaged so that rotational motion of the rotor is transmitted through the input member to the output member.

However, a friction clutch may be employed as the clutch mechanism. That is, disc-shaped or conical members are opposed to each other as an input member and an output member, and the rotational motion of the rotor 40 via the relay member 12 is caused by the frictional force when the input member rotates by the first rotation angle. The output member may be configured to rotate by a second angle of rotation that is less than the first angle of rotation. In the input member and the output member, by adjusting the frictional force that acts by changing the shape, material, surface roughness, etc. of the contact surface between the disk-shaped or conical-shaped surfaces that are arranged to face each other, The rotation angle transmitted to the output member may be adjusted. As a result, the rotor 40 can be made to make one revolution with an arbitrary number of strokes, and the writing lead can be extended with an arbitrary number of strokes. The contact surface between the input member and the output member may be made of rubber, sandpaper, or the like, for example. Any clutch mechanism other than dog clutches and friction clutches may be employed.

In the embodiment described above, since the ball chuck 11 and the input clutch cam 61 are connected, the ball chuck 11 receives the rotational driving force of the rotor 40 via the relay member 12 and the input clutch cam 61 to rotate. By doing so, the writing lead 7 was configured to rotate. However, the ball chuck 11 and the input clutch cam 61 may not be connected. In short, the clutch mechanism may be applied to mechanical pencils in which the writing lead is not configured to rotate.

After the writing lead 7 is pulled out from the ball chuck 11 by a knocking operation or by the operation of the lead feeding mechanism and before writing pressure is applied to the writing lead 7, there is structurally enough room for the writing lead to move back further. rush). Therefore, if the amount of the writing lead 7 actually extended is small, the drawn-out writing lead 7 may retreat due to the backlash, and the writing lead 7 may not actually be extended.

According to the clutch mechanism, the timing or frequency of feeding the writing lead 7 by the lead feeding mechanism can be delayed. Therefore, according to the clutch mechanism, it is possible to extend the writing lead 7 more after the writing lead 7 is worn out more, thereby substantially preventing the writing lead 7 from being extended due to the influence of the backlash. be able to. The amount of feeding of the writing lead can be changed by adjusting the step height H of the lead feeding mechanism as described above. Therefore, according to the above-described embodiment, it is possible to provide a mechanical pencil having a lead feeding mechanism that allows the writing lead to be fed more reliably.

As shown in FIG. 1, the mechanical pencil 1 further has a cap 70 which is provided with a clip 70a and fitted with the barrel 6. As shown in FIG. The cap 70 has a cover cap 71 , a core feeding member 72 as a core feeding portion, and a cushion spring 73 . In this specification, in the axial direction of the cap 70, the closed end side is defined as the "front" side, and the open end side is defined as the "rear" side. A lead feeding mechanism using the lead feeding portion of the cap 70 will be described with reference to FIGS. 20 and 21. FIG.

As shown in FIGS. 1 and 21B, the cover cap 71 is a cap-shaped member with a closed front end. A cover cap 71 is attached to the front end of cap 70 to form the closed end of cap 70 . The lead feeding member 72 is arranged inside the front end of the cap 70 so as to be movable back and forth. A cushion spring 73 is arranged between the cover cap 71 and the core feeding member 72, and the cushion spring 73 biases the core feeding member 72 rearward.

20 is a longitudinal sectional view of the lead feeding member 72. FIG. The lead feeding member 72 is a cylindrical member. In FIG. 20, the cap 70 is arranged so that the left side is the front side of the cap 70 . The rear end surface of the lead feeding member 72 is provided with an insertion hole 72a which is a circular opening into which the tip of the mechanical pencil 1, that is, the slider 9 and the like is inserted. The bottom surface of the insertion hole 72a is provided with a housing recess 72b having a cylindrical inner peripheral surface with an inner diameter R narrower than the entrance of the insertion hole 72a and a depth D2. A tapered surface 72c is provided behind the accommodation recess 72b. The inner diameter R of the accommodating recess 72b is set according to the outer diameter of the writing lead 7 used in the mechanical pencil 1. As shown in FIG. Specifically, the inner diameter R of the accommodating recess 72b is set slightly larger than the outer diameter of the writing lead 7, and is set so that the tip of the writing lead 7 is accommodated therein.

FIG. 21 is an enlarged cross-sectional view of the mechanical pencil 1 for explaining how the writing lead 7 is extended. FIG. 21(A) shows the state of the mechanical pencil 1 before the writing lead 7 is drawn out, in which the cap 70 is not fitted to the barrel 6, and FIG. 21(B) shows the barrel 6. 21(C) shows the state of the mechanical pencil 1 with the cap 70 fitted to the shaft cylinder 6, and FIG. 1 state.

In FIG. 21(A), the writing lead 7 does not protrude from the slider 9 . That is, it shows a state in which the user retracts the writing lead 7 so as not to protrude from the slider 9 in order to protect the writing lead 7 after completing a series of writing operations.

Next, as shown in FIG. 21B, the cap 70 is fitted onto the barrel 6. Then, as shown in FIG. At this time, the tip of the mechanical pencil 1 , that is, the tip of the writing lead 7 and the slider 9 are inserted into the insertion hole 72 a of the lead feeding member 72 . As described above, since the inner diameter R of the storage recess 72b is set according to the outer diameter of the writing lead 7, the storage recess 72b receives the tip of the writing lead 7. As shown in FIG. On the other hand, the outer diameter of the tip of the slider 9 is set larger than the inner diameter R of the housing recess 72b. Therefore, when the slider 9 is inserted into the cap 70, the tip of the slider 9 is not accommodated in the accommodation recess 72b and is retained on the tapered surface 72c. As a result, the slider 9 retreats in the barrel 6 relative to the writing core 7, and as a result, writing is performed in the cap 70 from the tip of the slider 9 by the same length as the depth D2 of the recess 72b. A core 7 protrudes.

Then, as shown in FIG. 21(C), the cap 70 is removed from the barrel 6 to start the next writing operation. At this time, the retreated slider 9 and the holding chuck 10 arranged inside the slider 9 advance due to the biasing force of the cam contact spring 18 . As a result, the writing lead 7 held by the holding chuck 10 is pulled out from the ball chuck 11 and relatively extended from the tip of the slider 9 by the depth D2 of the accommodation recess 72b. Therefore, the amount of the writing lead 7 that is drawn out, that is, the amount of drawing out, is equal to the depth D2 of the housing recess 72b.

In general, the user retracts the writing lead so that it does not protrude from the tip member or the slider in order to protect the writing lead after completing a series of writing motions. Therefore, before starting the next writing action, it is necessary to perform the knocking operation at least once to extend the writing lead in advance. Even with a mechanical pencil having the above-described lead feeding mechanism, a writing action is necessary to automatically feed the writing lead. It is necessary to pay out the writing core in advance.

According to the lead feeding member 72 , the writing lead 7 is fed simply by attaching and detaching the cap 70 to and from the barrel 6 . That is, the writing lead can be extended without performing a knocking operation before starting the writing action. Therefore, it is possible to provide a mechanical pencil that allows a new core feeding operation that is different from the conventional knocking operation.

Even if the writing lead 7 protrudes from the slider 9 longer than the depth D2 of the housing recess 72b and the cap 70 is fitted onto the barrel 6, the amount of protrusion of the writing lead 7 does not change. That is, in this state, the tip of the slider 9 does not engage with the tapered surface 72c, and therefore the slider 9 does not retreat relative to the writing core 7 within the barrel 6. As shown in FIG. At this time, the lead feeding member 72 is pressed by the tip of the writing lead 7 protruding longer, but the pushing force is absorbed by the lead feeding member 72 moving forward against the biasing force of the cushion spring 73 .

The lead feeding member 72 may be replaceable by removing the cover cap 71 . That is, the amount of protrusion of the writing lead 7 differs from user to user. For example, if the writing lead 7 protrudes sufficiently, it is convenient for the user to write for a long time, and if the writing lead 7 does not protrude further, the user does not have to worry about the writing lead 7 breaking. Some users feel that it is preferable from Therefore, lead feeding members 72 having storage recesses 72b with various depths D2 may be prepared in advance so that they can be replaced according to user's preference. The cushion spring 73 may be omitted, and the lead feeding member 72 may be fixed and arranged inside the front end of the cap 70 .

The lead feeding portion, which is the lead feeding member 72, can be arbitrarily configured as long as the slider 9 can be pushed back with respect to the writing lead 7 when the cap 70 is fitted to the barrel 6. good too. That is, as long as the tip of the writing lead 7 is received in the housing recess 72b when the cap 70 is fitted, and the tip of the slider 9 is not received in the housing recess 72b but is locked and retracted. The shape and the like of the accommodation recess 72b may be configured arbitrarily. For example, it may be a plurality of inwardly extending protrusions formed on the inner peripheral surface of the cap 70 so as to retract the slider 9 with respect to the writing core 7 when the cap 70 is fitted.

In the above-described embodiment, the slider 9 is urged forward by the cam contact spring 18 in order to operate the core feeding mechanism. However, the lead feeding member 72 of the cap 70 may be applied to a mechanical pencil whose slider is not biased forward. The mechanical pencil may or may not have a ball chuck. For example, a pipe-shaped lead guide, which is a slider attached to the proboscis member, advances along with the protruding motion of the writing lead associated with the knocking operation, and the pipe slide operates so that the lead guide moves backward as the writing lead wears out due to writing. The lead feeding member of the cap may be applied to the mechanical pencil of the type.

22 is an enlarged perspective view of the cap 70. FIG. The inner peripheral surface of the cap 70, specifically, the inner peripheral surface in the vicinity of the opening end, is provided with a plurality of, specifically three, positioning recesses 70b arranged at equal intervals along the circumferential direction. The positioning recess 70b is a recess that opens toward the rear and is formed in a bell-shaped curve when viewed radially outward from the central axis. That is, a convex surface 70ba is formed on the inner surface of the positioning recess 70b on the front side, and a concave surface 70bb is formed on the inner surface of the positioning recess 70b on the rear side.

23 is an enlarged perspective view of the barrel 6. FIG. As shown in FIG. 23 and further in FIG. 2, the outer peripheral surface of the shaft cylinder 6 is provided with a plurality of, specifically three, positioning protrusions 6a arranged at equal intervals along the circumferential direction. there is The positioning protrusion 6a is a protrusion extending forward. A convex curved surface 6aa is formed on a part of the outer surface on the front side of the positioning convex portion 6a. The convex curved surface 6aa of the positioning protrusion 6a is complementary to a part of the convex curved surface 70ba of the positioning recess 70b. That is, the positioning protrusion 6a and the positioning recess 70b have complementary portions.

As shown in FIGS. 1 and 21B, an annular magnet 80 is arranged inside the cap 70 . Magnet 80 is, for example, a neodymium magnet. Instead of the annular magnet 80, a plurality of magnets may be arranged at equal intervals along the circumferential direction. On the other hand, the gripping portion 8 described above is a first magnetic body manufactured from a magnetic material. The magnet 80 is arranged inside the cap 70 so that when the cap 70 is fitted onto the barrel 6 , a magnetic attraction force acts between the magnet 80 and the grip portion 8 .

When fitting the cap 70 onto the barrel 6 , the barrel 6 is usually held with one hand, the cap 70 is held with the other hand, and the open end of the cap 70 is inserted into the barrel 6 . do. When the cap 70 is inserted into the barrel 6 to a predetermined depth, the cap 70 is pulled deeper by the magnetic force acting between the grip portion 8 and the magnet 80 . At this time, if the positioning convex portion 6a of the shaft cylinder 6 and the positioning concave portion 70b of the cap 70 are aligned along the axial direction, the positioning convex portion 6a and the positioning concave portion 70b are fitted without interfering with each other. Fitting of the cylinder 6 and the cap 70 is performed. On the other hand, the positioning convex portion 6a of the barrel 6 and the positioning concave portion 70b of the cap 70 may not be aligned along the axial direction, that is, may be shifted in the circumferential direction.

When the positioning convex portion 6a of the shaft cylinder 6 and the positioning concave portion 70b of the cap 70 are slightly displaced in the circumferential direction, the convex curved surface 6aa of the positioning convex portion 6a and the concave curved surface of the positioning concave portion 70b are subjected to magnetic attraction force. 70bb abut. As a result, the positioning convex portion 6a and the positioning concave portion 70b cooperate to rotate the barrel 6 or the cap 70 around the central axis so that the positioning convex portion 6a and the positioning concave portion 70b are fitted, and the barrel 6 and the cap 70 matings are performed.

If the positioning convex portion 6a of the shaft cylinder 6 and the positioning concave portion 70b of the cap 70 are largely displaced in the circumferential direction, the convex curved surface 6aa of the positioning convex portion 6a and the concave curved surface of the positioning concave portion 70b will not be affected by the magnetic attraction force. 70bb does not abut. Therefore, the positioning convex portion 6a and the positioning concave portion 70b do not cooperate with each other, and the fitting between the shaft cylinder 6 and the cap 70 is not performed. Here, the cap 70 is held with one hand, and the cap 70 is rotated around the central axis until the convex curved surface 6aa of the positioning convex portion 6a and the concave curved surface 70bb of the positioning concave portion 70b abut against each other. As a result, the positioning convex portion 6a and the positioning concave portion 70b cooperate to rotate the barrel 6 or the cap 70 around the central axis so that the positioning convex portion 6a and the positioning concave portion 70b are fitted, and the barrel 6 and the cap 70 matings are performed.

Fitting between the barrel and the cap is generally performed in a snap-fitting fashion by allowing projections formed on the inner peripheral surface of the cap to climb over projections formed on the outer peripheral surface of the barrel. According to the above-described embodiment, the cap 70 does not need to be strongly pressed against the barrel 6 because the fitting between the barrel 6 and the cap 70 is performed using magnetic attraction force. As a result, even if the cap 70 is inserted obliquely with respect to the central axis of the barrel 6 , there is no fear that the edge of the open end of the cap 70 will damage the outer peripheral surface of the barrel 6 . Also, even children and elderly people with weak strength can easily fit the barrel 6 and the cap 70 together.

Furthermore, if the outer surfaces of both the barrel 6 and the cap 70 are provided with identification marks, letters, patterns, or other identification marks or designs, or if a characteristic shape is attached, the barrel 6 and the cap 70 can be rotated about the central axis. can be positioned correctly with respect to In short, according to the above-described embodiment, it is possible to provide a writing instrument in which the cap can be accurately fitted to the barrel. Furthermore, since the magnetic force tends to be stronger as the relative distance is shorter, the barrel 6 and the cap 70 collide with each other vigorously when the fitting is completed. As a result, the user can feel a comfortable click feeling and click sound, and can recognize that the fitting has been securely performed.

As shown in FIGS. 1, 2 and 4, a second magnetic body 81 made of a magnetic material may be arranged at the rear end of the barrel 6, that is, at the rear end of the rear axle 3. good. As a result, even when the cap 70 is fitted to the rear end portion of the barrel 6 for writing, the attractive force of the magnetic force can be utilized. In this case, a positioning projection 6a that cooperates with the positioning recess 70b of the cap 70 may be provided at the rear end of the barrel 6. As shown in FIG. In the above-described embodiment, the positioning protrusions 6a are formed on the outer peripheral surface of the barrel 6 and the positioning recesses 70b are formed on the inner peripheral surface of the cap 70. However, the positioning recesses are formed on the outer peripheral surface of the barrel 6. , a positioning protrusion may be formed on the inner peripheral surface of the cap 70 . Note that the mechanical pencil 1 does not have to have the second magnetic body 81 .

In the above-described embodiment, the magnet 80 is arranged on the cap 70 side, and the first magnetic body, which is not a magnet, is arranged on the barrel 6 side. For example, a magnet may be arranged inside the grip portion 8 . However, since the gripping portion 8 is exposed to the outside with the cap 70 removed, the magnetic material around the gripping portion 8, such as a desk clip, is not attracted to the shaft cylinder 6 side. It is preferable to dispose the first magnetic body. Magnets may be arranged on both the barrel 6 and the cap 70 . The first magnetic body may be provided in a portion of the shaft tube 6 other than the grip portion 8 .

Although three positioning protrusions 6a and three positioning recesses 70b are formed in the above embodiment, the number may be one, two, or four or more. When the positioning protrusion 6a and the positioning recess 70b are slightly displaced in the circumferential direction, the positioning protrusion 6a and the positioning recess 70b cooperate with each other to rotate the barrel 6 or the cap 70 around the central axis so that the barrel 6 and the cap 70 can be fitted. As long as it is done, it may be configured arbitrarily. For example, the positioning protrusion 6a shown in FIG. 23 may be formed completely complementary to the positioning recess 70b shown in FIG.

As described above, the fitting using the magnetic attraction force between the barrel and the cap can be applied not only to mechanical pencils but also to other writing instruments such as ballpoint pens, sign pens, marker pens, fountain pens, and thermochromic writing instruments. may be applied to. The positioning convex portion 6a and the positioning concave portion 70b may be omitted, and the writing instrument may be configured such that the shaft tube and the cap are simply fitted together using magnetic attraction force.

24 is a perspective view of the holding chuck 10, and FIG. 25 is a longitudinal sectional view of the holding chuck 10. FIG. In FIG. 25, the mechanical pencil 1 is arranged so that the left side is the front side. As described above, the holding chuck 10 is formed with the through hole 10a extending along the axial direction. The holding chuck 10 has a cylindrical small diameter portion 10b and a flange portion 10c provided on the outer peripheral surface of the rear end portion of the small diameter portion 10b. Inside the front side of the through hole 10a, a lead holding portion 10d narrowed compared to other portions is provided. A rearwardly widening conical surface 10e is provided inside the through hole 10a behind the lead holding portion 10d.

As shown in FIG. 24, the lead holding portion 10d of the through hole 10a is an elongated hole. Specifically, the cross-sectional shape of the lead holding portion 10d of the through hole 10a is a rectangle with rounded corners. The lead holding portion 10d of the through hole 10a may be an elongated hole. Therefore, the cross-sectional shape of the lead holding portion 10d may be an oval, specifically an oval or an ellipse. good too. The size of the slot, for example, the length and width or aspect ratio in the case of a rectangle with rounded corners, or the length of the major axis and the minor axis in the case of an ellipse, is the same as that of the writing lead 7 generally used in the mechanical pencil 1. It is determined in advance by experiments or the like according to the outer diameter or the composition of the writing lead 7 .

Since the lead holding portion 10d of the through hole 10a is an elongated hole, it is more likely to be elastically deformed than a typical round hole lead holding portion. That is, the elongated hole is less likely to be elastically deformed in the same direction as the circular hole in the direction along which the elongated shape extends. elastic deformation more easily. Therefore, even if there is some variation in the outer diameter of the writing lead 7 or the size of the through hole of the holding chuck 10 during manufacturing, it can be absorbed by elastic deformation in the direction orthogonal to the extending direction of the elongated shape. can. Therefore, it is possible to provide a mechanical pencil in which the sliding resistance between the writing lead 7 and the holding chuck 10 can be set more appropriately.

In a general mechanical pencil, sliding contact between the writing lead and the holding chuck is performed only when the writing lead is extended by a knocking operation. On the other hand, as described above, in the mechanical pencil 1 provided with the rotation drive mechanism and the lead feeding mechanism, the sliding contact between the writing lead 7 and the holding chuck 10 occurs not only when the writing lead 7 is pushed out by the knocking operation. It is also performed during normal writing operations. Therefore, it is preferable to strictly set the sliding resistance between the writing lead and the holding chuck so that the rotation driving mechanism and the lead feeding mechanism function properly. In the mechanical pencil 1, since the lead holding portion 10d of the through hole 10a is an elongated hole, the sliding resistance between the writing lead 7 and the holding chuck 10 can be set more strictly.

The holding chuck 10 is made of an elastic material such as NBR, EPDM, fluororubber or silicone rubber. In particular, the holding chuck 10 made of fluororubber is preferable from the viewpoint of creep resistance and chemical resistance. That is, although the writing lead 7 contains some oil component, the effect of the oil component can be further reduced by manufacturing the holding chuck 10 from fluororubber. As a result, various types of oil components and their blends can be selected for the writing lead 7, making it possible to manufacture a wider variety of writing leads. In this case, the lead holding portion 10d may not be an elongated hole, and may have a general circular cross-sectional shape.

In the above-described embodiment, the holding chuck 10 has the cylindrical small diameter portion 10b, but the holding chuck may be tapered as a whole. In short, the holding chuck 10 may have any external shape as long as the lead holding portion 10d of the through hole 10a is an elongated hole.

REFERENCE SIGNS LIST 1 mechanical pencil 2 front barrel 3 rear barrel 4 tip member 6 barrel 6a positioning projection 7 writing lead 8 grip portion (first magnetic body)
9 slider 10 holding chuck 10a through hole 10d lead holding part 11 ball chuck 12 relay member 17 coil spring 18 cam contact spring 19 lead case 20 knock bar 21 coil spring 30 rotary drive mechanism 40 rotor 50 dial cam member 51 dial cam 52 Rail cam member 53 Rail cam 54 Feeding cam surface 55 Step 56 Coil spring 60 Clutch mechanism 61 Input clutch cam 62 Output clutch cam 63 Clutch cam surface 64 Transmission cam 65 Feeding cam 65c Abutment 66 Clutch cam holder 70 Cap 70b Positioning recess 71 Cover cap 72 core feeding member 72a insertion hole 72b housing recess 73 cushion spring 80 magnet 81 second magnetic body

Claims (5)

comprising a barrel and a cap,
One of the outer peripheral surface of the barrel and the inner peripheral surface of the cap is formed with a positioning protrusion and the other is formed with a positioning recess,
If the shaft cylinder and the cap are to be fitted in a state where the positioning convex portion and the positioning recessed portion are not aligned along the axial direction, the attractive force due to the magnetic force acting between the shaft cylinder and the cap will cause the above The positioning convex portion and the positioning concave portion cooperate to rotate the barrel or the cap about the center axis, and the positioning convex portion and the positioning concave portion are fitted to each other, and the barrel and the cap are fitted. A writing instrument configured to be worn. 2. A writing instrument according to claim 1, wherein said positioning protrusion and said positioning recess have portions complementary to each other. 3. The writing instrument according to claim 1, wherein a plurality of said positioning protrusions and said positioning recesses are provided at equal intervals along the circumferential direction. 4. The writing instrument according to any one of claims 1 to 3, wherein the barrel is configured such that the cap can be fitted to the front end portion of the barrel by magnetic attraction force. 5. The writing instrument according to claim 4, wherein the barrel is configured so that the cap can be fitted to the rear end portion of the barrel by magnetic attraction force.

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