JP2007001154A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which is so devised as to prevent letting-out or the like of an unnecessary lead even when a finger of the hand touches in writing a slide member for letting out the lead which is provided to be slidable axially in the lateral part of a holder tube. <P>SOLUTION: A cam member 12 having a cam face 14 formed as a slant is fitted rotatably to a fixed member 6 fixed in a holder tube 2. A projection 44 for contact formed on the slider main body 41 of a slider 35 and a projection 19 formed on a lead tank 16 are brought into contact with the cam face at the opposite sides in the radial direction. A compression spring 26 works on the lead tank. When the slider is moved back axially, the cam member rotates and advances the lead tank so as to let out the lead. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a mechanical pencil, and more specifically, to an improvement in a mechanical pencil lead feeding mechanism.

  The lead of the mechanical pencil is normally fed by pressing a knock button provided at the rear end of the shaft cylinder. In this case, it is necessary to change the mechanical pencil for feeding the lead during writing.

By the way, there is a so-called side knock type mechanical pencil in which a member for feeding the core is slidably provided on a side portion of the shaft cylinder. For example, in the mechanical pencil disclosed in Japanese Utility Model Laid-Open No. 6-42258, an operation portion is slidably disposed on a side portion of the shaft cylinder, and the operation portion is advanced to the shaft tip side to thereby move the lead tank through the moving portion. The chuck is advanced and opened together with the stop spring, and the chuck is moved forward to open, and the manipulator is retracted to retract the lead tank and close the chuck. In such a side knock type mechanical pencil, when the lead is drawn out during writing, it is possible to move the fingertip as it is, and there is no need to change the hand, which is convenient.
Japanese Utility Model Publication No. Hei 6-42258

  By the way, when writing with a mechanical pencil, writing pressure is required, and a finger gripped so as to press the tip of the core against the paper surface exerts a force to press the shaft toward the paper surface side. Therefore, in the case of the above-described conventional example, if the finger gripped during writing hits the operation part, the force that always pushes the lead tank toward the tip end side of the shaft is forced, and unnecessary lead feeding is performed. There is a possibility that the core breaks frequently.

  The present invention has been made in view of the above-described conventional problems, and even if the finger of the hand grasping the slide member for feeding the core provided on the side of the shaft cylinder so as to be slidable in the axial direction hits the core tank It is another object of the present invention to provide a mechanical pencil that prevents a force from being applied to the chuck in the direction in which the lead is fed out and prevents the lead from being drawn out unnecessarily.

In order to solve the above-described problems, the present invention provides a shaft cylinder, a core tank that is housed in the shaft cylinder and includes a chuck on the tip side, a chuck ring that opens and closes the chuck, and moves the core tank in the axial direction of the shaft cylinder. A mechanical pencil including a slide member disposed on a side portion of the shaft cylinder so as to be slidable in an axial direction of the shaft cylinder, and disposed in the shaft cylinder, engaged with the slide member and the core tank, A moving direction conversion member is provided that transmits the movement of one of the slide member and the core tank to the other so that the axial movement of the core tank is opposite. Accordingly, the chuck can be advanced in the axial direction by moving the slide member rearward in the axial direction, and the lead can be fed out.
In one embodiment, the moving direction converting member includes a cam portion, and the abutting portion that abuts the cam portion is provided on the slide member and the core tank. By using the cam, the movement direction can be converted with the minimum number of members.
In one embodiment, the moving direction converting member is provided so as to be rotatable around the axis of the shaft cylinder. As a result, the movements of the members involved in the direction change are only linear movements and rotational movements, and there is no difficulty in the operation, the direction of movement can be surely changed, and failure is unlikely to occur.
In one embodiment, the cam portion is formed as an inclined surface inclined with respect to the axis of the shaft cylinder. Accordingly, the moving direction can be changed by bringing the slide member and the core tank into contact with the same cam surface at a position opposite to the radial direction, so it is sufficient to form a single cam surface.
In one embodiment, the moving direction conversion member is formed in a columnar shape or a cylindrical shape, and the inclined surface is formed by cutting the columnar shape or the cylinder obliquely with respect to the axial direction. As a result, the shape of the cam member is extremely simple and can be manufactured very easily.

  In the present invention, the lead can be extended by moving the slide member rearward in the axial direction. Normally, when the pen is held, the slide member does not have a force to move it rearward in the axial direction, and the lead is not used unnecessarily and the core is not broken frequently.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded view of a mechanical pencil 1 according to an embodiment of the present invention, and FIG. 2 is a side sectional view of a main part. In the figure, reference numeral 2 denotes a cylindrical shaft, and a known tail plug 3 having a clip 3a is attached to the rear end side, and a tip 4 having a known pipe 4a is attached to the distal end side. The tip 4 is removably attached to the threaded portion 2a formed on the distal end side of the shaft tube by screw coupling, and a rubber chip 5 having a known through-hole is also disposed therein.

  Reference numeral 6 denotes a short cylindrical fixing member, which has a through-hole 11 and includes a large-diameter portion 7 having a large outer diameter and a small-diameter portion 8 having a small outer diameter (see FIG. 3). On the outer periphery of the large-diameter portion 7, a low-profile ridge 9 extending in the circumferential direction is formed, and this ridge 9 is fitted in a groove 2b formed on the inner periphery of the shaft tube 2 in the circumferential direction. The fixing member 6 is positioned in the axial direction with respect to the shaft tube 2. Further, four grooves 10 extending in the axial direction are formed on the outer periphery of the large-diameter portion 7 at intervals of 90 degrees in the circumferential direction, and three of these grooves 10 are circumferential on the inner periphery of the shaft tube 2. The ribs 2c extending in the axial direction and formed at three places at intervals of 90 ° C. in the direction are fitted, and the fixing member 6 is prevented from rotating with respect to the shaft cylinder 2.

  Reference numeral 12 denotes a cam member, which is a cylindrical member having a through-hole 13 and is rotatably fitted to the small-diameter portion 8 of the fixing member 6 at one end side, that is, the rear end side thereof (see FIG. 4). A cam surface 14 is formed which is obliquely cut with respect to the axis at the other end, that is, the front end, and is inclined with respect to the axis. The cam member 12 will be described later again.

  Reference numeral 16 denotes a core tank that can store a plurality of cores, and has a generally cylindrical shape as known (see FIG. 5). The lead tank 16 includes an insertion portion 17 having a relatively small outer diameter from the rear end side (right side) in FIG. 5, an intermediate body portion 18 having a relatively large outer diameter, and a chuck having a small outer diameter on the front end side. The mounting portion 19 is included. The lead tank 16 is inserted into the through hole 11 of the fixing member 6 at the insertion portion 17 and is movable in the axial direction. FIG. 2 shows a state in which the lead tank 16 is retracted, but the insertion portion 17 is not detached from the through hole 11 of the fixing member 6 even when the lead tank 16 is advanced as will be described later.

  The outer diameter of the main body portion 18 is a size corresponding to the diameter of the through hole 13 of the cam member 12 described above. On the outer periphery of the main body 18, an abutting protrusion 19 having a shape similar to a home base in a plan view is formed as shown in FIG. As will be described later, the lead tank 16 is biased toward the right side in FIG. 2, that is, toward the rear end side of the shaft, and the portion on the right side from the protrusion 19 of the main body portion 18 enters the through hole 13 of the cam member 12. The pointed contact portion 19a on the rear end side of the protrusion 19 is in contact with the cam surface 14 and is positioned at that position. Further, on the outer periphery of the front end portion of the main body 18, guide portions 20 are provided at two positions that are separated from the protrusions 19 by 90 ° in the circumferential direction and are opposed to each other in the diametrical direction. The guide portion 20 is formed in a state of protruding on the outer periphery, and a guide groove 21 extending in the axial direction of the core tank 1 is formed. The guide groove 21 is fitted with the rib 2c of the shaft cylinder 2 described above. As a result, the lead tank 16 is prevented from rotating and can only move in the axial direction.

  A chuck 31 (to be described later) is inserted and attached to the chuck attachment portion 22. A hole 23 is formed in the core tank 16 over its entire length, and this hole 23 has a diameter at the large diameter portion 24 and the chuck mounting portion 22 where the diameter is large at the insertion portion 17 and the body portion 18. And a small-diameter portion 25 having a small diameter. The large-diameter portion 24 has a size that can accommodate a plurality of cores. A shoulder portion 26 is formed between the main body portion 18 and the chuck mounting portion 22, and a compression spring 29 is disposed between the shoulder portion 26 and the spring receiving portion 2 d formed on the shaft tube 2. The tank 16 is always urged to the right in FIG. The small-diameter portion 25 of the through hole 23 formed in the chuck attachment portion 22 is slightly enlarged in diameter near the left end portion thereof, and a shoulder portion 27 that extends in the radial direction is formed to constitute a stop portion 27 that stops the chuck described later. .

  Reference numeral 31 is a known chuck, and the front side 31a is divided into a plurality of pieces along the axial direction. The chuck 31 is inserted from the front end 2e side of the shaft cylinder 2, the rear end side is inserted into the small diameter hole 25 of the chuck mounting portion 22 of the core tank 16, and the portion whose diameter is increased in the axial direction is the chuck stop. It is attached in a state of being positioned in contact with the portion 27. Since these structures are well-known, detailed description is abbreviate | omitted. Reference numeral 32 is a ring with a flange 32 a for opening and closing a known chuck, and is fitted to the tip 2 e of the shaft cylinder 2 in a state of covering the tip of the chuck 31. FIG. 2 shows a state in which the chuck is closed. When the lead tank 16 moves to the tip end side of the shaft cylinder, the ring 32 moves together with the chuck 31. When the ring 32 hits the shoulder 4a formed on the tip 4, the ring 32 is prevented from further movement, only the chuck 31 moves, and the chuck opens. These are also known, and further description is omitted.

  The shaft cylinder 2 is slightly elongated in the axial direction at a position substantially opposite to the side facing the abutment protrusion 19 within a range slightly longer than both axial ends of the main body 18 of the core tank 16 in FIG. A slider opening 2f is opened, and a slider 35 is arranged facing the opening 2f. The outer peripheral side of the shaft tube 2 is a scooping portion 2g scooped at a depth that is a predetermined range around the opening 2f. The slider 35 includes a slider cover 36 and a slider body 41.

  First, the cover 36 will be described (see FIG. 6). The cover 36 has a main body portion 37 that is substantially arc-shaped in cross section and is long in the axial direction of the shaft tube 2. The radius of curvature of the inner surface side of the main body 37 is substantially the same as the outer diameter of the scooping portion 2g of the shaft tube 2, and the main body portion 37 is received by the scooping portion 2g and covers the shaft tube 2. The length of the scooping portion 2g in the axial direction of the shaft cylinder 2 is longer than the length of the main body portion 37 by the stroke of the slider 35. In the state of FIG. 2, the front edge of the main body portion 37 is in front of the scooping portion 2g. Although it contacts the edge wall, the chuck 31 can be opened by sliding it to the rear side as will be described later. A part of the outer peripheral surface of the main body 37 is raised on the rear side in the longitudinal direction of the shaft tube 2 to form a finger hook portion 38, which is convenient for sliding with the fingertip.

  A pedestal 39 that is concentric with the main body 37 and formed in an arc shape is formed on the inner peripheral side of the main body 37. The length of the pedestal 39 as viewed in the longitudinal direction of the shaft tube 2 is shorter than the opening 2 of the shaft tube 2 by the stroke of the slider 35, and the width (arc) on the side perpendicular thereto is the same as that of the opening 2 f. It is almost the same, so that it does not rattle in the width direction. In the state of FIG. 2, it abuts on the front edge of the opening 2 f, and there is a clearance corresponding to the stroke of the slider 35 on the rear side. The thickness of the pedestal 39 is such that the lower surface side slightly protrudes inward from the inner peripheral surface of the shaft tube 2. A total of six shafts 40 having short lengths extending downward are formed on the lower surface side of the base 39 in two rows of three in the longitudinal direction.

  The slider body 41 (see FIG. 7) is attached to the inner peripheral surface side of the pedestal 39. That is, the slider body 41 is also a member having an arcuate cross section, and the dimension in the axial direction of the shaft tube 2 and the width (arc) in the direction orthogonal thereto are substantially the same as those of the pedestal 39. And the hole 2 is formed corresponding to the axis | shaft 40 formed in the base 39, the axis | shaft 40 is engage | inserted in this hole 42 using press injection or an adhesive agent, and the cover 36 and the main body 41 are integrated. Yes. The slider main body 41 is formed with two overhang portions 42 that extend slightly in the circumferential direction, two on each side at a predetermined position in the axial direction. The slider 2 extends to both sides of the opening 2 f on the inner peripheral surface side of the cylinder 2 so that the slider 35 does not come off the shaft cylinder 2.

  On the inner peripheral surface of the slider main body 41, a contact projection 44 having a shape in plan view substantially the same as the contact projection 19 of the core tank 17 is formed. The protruding portion 44 has a pointed head portion 44a on the opposite side in the radial direction with respect to the portion where the contact portion 19 of the core tank 16 contacts the cam surface 14 of the cam member 13 described above. It comes to contact.

  Next, the lead feeding operation of the mechanical pencil 1 will be described. As described above, FIG. 2 shows a state in which the chuck 31 is retracted and closed. The lead tank 16 is urged backward by a spring 29, the ring 32 is stopped by the tip 2e of the shaft cylinder 2, the chuck 31 is gripped and closed, and the lead tank 16 is positioned at the position shown in the figure. The abutment protrusion 19 of the lead tank 16 abuts against the cam surface 14 of the cam member 12 to apply a force to rotate the cam member 12 in the direction of arrow C in FIG. Therefore, the cam member 12 exerts a force to move the slider 35 forward in the axial direction of the shaft cylinder. Then, the main body 37 or the pedestal 39 of the slider cover 36 is brought into contact with the front edge wall of the scooping portion 2g or the front edge of the opening 2f (only one of them is in contact), and each member is positioned at the position shown in FIG. Has been.

  When the slider cover 36 is moved rearward from the state of FIG. 2, the cam member 12 is moved in the direction opposite to the arrow C in FIG. Turn to. Then, the cam surface 14 acts on the contact protrusion 19 of the lead tank 16 to advance the lead tank 16. When the chuck 31 moves forward while being closed by the ring 32 and hits the shoulder 4a of the ring 32 tip 4, the movement is prevented, and the chuck 31 is further advanced to open the chuck 31. Further movement of the slider 35 is prevented when the main body 37 or the pedestal 39 of the slider cover 36 abuts against the rear side wall of the scooping portion 2g or the rear edge of the opening 2f (only one of them abuts). As a result, the lead is sent out. When the force applied to the slider cover 36 is removed, each member moves in the opposite direction by the action of the spring 26 and returns to the position shown in FIG.

It is an exploded view of a mechanical pencil according to an embodiment of the present invention. It is a sectional side view of the principal part. (A) is a front view and (A) is a cross-sectional view along line AA in (A). In the figure of a cam member, (A) is a front view, (A) is a sectional view taken along line BB of (A). It is a figure of a lead tank, (A) is a front view, (I) is a bottom view, (C) is a sectional view taken along the line DD of (A). It is a figure of a slider cover, (A) is a front view, (A) is a bottom view, and (C) is a side view. It is a figure of a slider main body, (A) is a front view, (I) is a bottom view, (C) is a side view.

Explanation of symbols

1: Mechanical pencil 2: Shaft cylinder 3: Tip 5: Fixing member 12: Cam member 14: Cam surface 16: Core tank 19: Abutment protrusion 29: Spring 31: Chuck 32: Chuck ring 35: Slider 36: Slider cover 41: Slider body 44: Abutment protrusion

Claims (5)

  A shaft cylinder, a core tank housed in the shaft cylinder and provided with a chuck on the tip side, a chuck ring for opening and closing the chuck, and a side portion of the shaft cylinder that moves the core tank in the axial direction of the shaft cylinder A mechanical pencil comprising a slide member arranged to be slidable in the axial direction of the shaft cylinder, disposed in the shaft cylinder, engaged with the slide member and the core tank, and the slide member and the core A mechanical pencil comprising a moving direction converting member for transmitting one movement of the slide member and the core tank to the other so that the axial movement of the tank is opposite.   2. The mechanical pencil according to claim 1, wherein the moving direction conversion member includes a cam portion, and the slide member and the core tank are provided with a contact portion that contacts the cam portion. Pencil.   3. The mechanical pencil according to claim 2, wherein the moving direction converting member is provided so as to be rotatable around an axis of the shaft cylinder.   4. The mechanical pencil according to claim 3, wherein the cam portion is formed as an inclined surface inclined with respect to an axis of the shaft cylinder.   5. The mechanical pencil according to claim 4, wherein the moving direction conversion member is formed in a columnar shape or a cylindrical shape, and the inclined surface is formed by cutting the columnar shape or the cylindrical shape obliquely with respect to the axial direction. A mechanical pencil characterized by that.

Images