JP2015123710A - mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil which enables writing at a sharp tip from the start of writing even with a new lead and recognition of a position of a lead corner part during writing.SOLUTION: In a mechanical pencil so constituted as to be capable of delivering a lead the cross section of which is formed into a polygon by a chuck, a chuck 6 is provided with a lead holding part 6d to keep a lead 5 held by the lead holding part 6d incapable of turning with respect to a barrel 2, and a plurality of guide parts 6i along which the lead 5 slides are formed behind of the holding part 6d.

Description

  The present invention relates to a mechanical pencil capable of feeding out a core having a polygonal cross section.

  In general, writing instruments are written with a slight tilt, but mechanical pencils with a circular core will reduce the length of the core when written with a tilt. It gradually became thicker. On the other hand, Patent Document 1 discloses a prior art in which a pencil core is formed into a polygonal column and writing is always possible with a sharp tip by using the corner of the core.

  However, in the prior art of Patent Document 1, there is no specification or suggestion about a means for determining whether the corner portion of the pencil lead formed on the polygonal column is in contact with the writing surface, and the corner portion of the pencil lead is written. It was difficult to use because it was necessary to write while always minding whether it was in contact with the surface.

  In Patent Document 2, the grip of a mechanical pencil is formed in a triangle, and the core is cut into a hexagonal pyramid by writing while rotating the shaft 120 degrees at a time, and can always be written with a constant thickness. Prior art is disclosed.

  However, in the prior art of Patent Document 2, since the core used is a circular core, there is a problem that the handwriting becomes thick until the tip is sharp in the core that has been newly used, and since it is a circular core, Since the handwriting becomes thick immediately when the core is scraped off at the time of writing, it is difficult to use with a certain writing width unless the shaft is rotated frequently.

JP-A-54-8022 Japanese Patent Application Laid-Open No. 10-100582

  In view of the above problems, the present invention enables writing with a sharp tip from the beginning of writing even with a new lead, reducing the thickening of the handwriting even if writing continues at the same axial position, and the corner of the lead is To provide a mechanical pencil capable of recognizing that it is in contact with a writing surface.

The present invention
“1. A mechanical pencil that feeds a lead having a polygonal cross section and side faces and corners by moving the chuck arranged in the shaft cylinder back and forth. A core holding part that is held immovably is formed, and a rotation stopping part that prevents the chuck from rotating with respect to the shaft cylinder while the chuck holds the core is provided in the shaft cylinder, A plurality of guide portions that are in sliding contact with the core are formed behind the core holding portion, and when the core passes between the guide portions forward, the outer shape of the core is the core holding portion by the guide portion. It becomes a holdable direction, the position of the corner of the core is fixed with respect to the shaft cylinder by holding the core with the core holding portion in the direction of the core, and the writing to the shaft cylinder at the time of writing Recognizes the state where the corner of the core is in contact with the writing surface Pencil was characterized in that a discriminating means for.
2. A plurality of elastic pieces are formed at the front portion of the chuck, and the elastic holding piece is provided with the core holding portion formed in a concave shape in accordance with the outer shape of the core so that the core holding portion and the side surface of the core are in contact with each other. 2. The mechanical pencil according to item 1.
3. A communication port through which the core passes is provided behind the chuck, and a rear end portion of the communication port is larger than the core and is formed in a circular shape or a polygonal shape through which only one core can pass, A front end portion of the connection port is formed in a polygonal shape that is the same shape and slightly larger than the core, and a cross-section of the connection port is formed by gradually changing from the rear end portion to the front end portion in a tapered shape, 3. The mechanical pencil according to item 1 or 2, wherein the guide part is an inner wall divided into a plurality of sections.
4). The outer shape of the shaft cylinder is formed in the same polygonal shape as the core, and a side surface and a corner portion are provided along the shaft center, and the side of the core is opposite to the corner portion of the shaft tube with the shaft center interposed therebetween. Recognizing a state in which the corner portion of the core is in contact with the writing surface at the corner portion of the shaft cylinder by forming the core holding portion of the chuck so that the corner portion is positioned and holding the core. The mechanical pencil according to any one of claims 1 to 3, which constitutes the discriminating means.
5. A convex portion or a concave portion is formed on the outer diameter of the shaft cylinder, and the core of the chuck is positioned so that the corner portion of the core is located on the opposite side of the axial center with respect to the convex portion or the concave portion. 1 thru | or comprised the said discrimination means for recognizing the state which the corner | angular part of the said core contact | abutted in the convex part or the concave part by forming the holding | maintenance part and holding | maintaining the said core. 4. The mechanical pencil according to any one of items 3.
6). 6. The tip according to any one of claims 1 to 5, wherein a tip port through which the core can pass is formed in front of the shaft cylinder, and a cross section of the tip port is formed in a polygon having the same shape and slightly larger than the core. mechanical pencil. It is.

According to the first configuration, the mechanical pencil of the present invention can feed out a core having a cross section formed in a polygonal shape, and writing at a pointed tip from the beginning of use of the core by writing at the corner of the core. It becomes possible. In addition, the chuck can be held non-rotatable by the chuck core holding part, and the chuck can be rotated with respect to the shaft cylinder by the rotation stopper provided on the shaft cylinder, so that the core can be rotated with respect to the shaft cylinder. Can be held impossible. Thereby, it is possible to prevent the lead from rotating during writing or feeding out the lead. As a means for making the shaft cylinder and the chuck non-rotatable, for example, a concave portion extending in the longitudinal direction is formed in a rotation stopper provided in the shaft cylinder, and a convex portion is formed on the side surface of the chuck so as to be in sliding contact. Alternatively, the convex and concave portions may be formed on the rotation stop portion and the concave portions may be formed on the side surfaces of the chuck by reversing the relationship between the concave and convex portions.
Also, by providing a guide part behind the lead holding part, the lead that has passed through the guide part and reached the lead holding part has the same position as the lead outer shape and the lead holding part. Thus, the lead can be securely held.

  Furthermore, since the shaft cylinder is provided with means for determining in which direction the corner of the core is located with respect to the shaft cylinder, it is possible to recognize whether the corner of the core is in contact with the writing surface during writing. it can. In addition, when writing, the corners of the core are shaved and the handwriting becomes thicker, by rotating the shaft cylinder and bringing another corner of the polygonal core into contact with the writing surface, writing with a sharp point always Is possible.

  The core used in the present invention is not particularly restricted so long as the number of corners is three or more so that the cross section forms a polygon, but the corners become obtuse as the number of corners increases, so that the sharp tip In order to write with, it is preferable that the number of corners is hexagon or less. Further, in order to write while maintaining a state where the width of the handwriting is thin, the effect becomes larger as the number of core corners is smaller, and therefore, it is more preferable to use a triangular shape. Furthermore, the cross-sectional shape of the core is preferably a regular polygon in which the angles of all corners are the same so that the corner can always be written with the same handwriting width regardless of which corner is used. More preferably, it is an equilateral triangle.

  According to the second configuration, a plurality of elastic pieces are provided at the front part of the chuck, a core holding part is formed inside each elastic piece, and the core shape is formed so that the core holding part and the side surface of the core are in contact with each other. Therefore, the core can be held so as not to rotate. In addition, by providing a gap between the core holding portion and the corner portion of the core, it is possible to prevent the corner portion from being lost when the core is held, and it is possible to always perform writing at a sharp corner portion, which is preferable. .

According to the third configuration, the communication port is provided at the rear of the chuck, and only one core can pass through the rear end of the communication port, and the core is formed in a circle or a polygon larger than the cross section of the core. This makes it easy to enter the connection port from the top, prevents clogging, forms a cross section at the front end of the connection port in a polygon that is the same shape and slightly larger than the core, and gradually leads the connection port from the rear end to the front end. By forming it in a concave shape, the lead passing through the contact port moves forward with the corners slidingly contacting a plurality of guide portions formed on the inner wall of the contact port, and the position of the corner moves, and the tip of the lead moves When passing through the front end of the communication port, the position of the side surface of the core can be matched with the position of the core holding portion.
As another means for matching the positions of the core holding portions of the corners of the core, it is possible to correct the positions of the corners by providing protrusions in the communication ports and sliding the cores on the protrusions.

  According to the fourth configuration, the outer shape of the shaft tube is formed in the same polygonal shape as the core, and the corner portion of the shaft tube is located on the opposite side of the shaft center with respect to the corner portion of the core. Therefore, when the corner portion of the core is brought into contact with the writing surface, the corner portion of the shaft cylinder automatically comes to a position where it can be easily seen, so that it is easy to write while always bringing the corner portion of the core into contact with the writing surface. Become.

  Furthermore, if the outer shape of the cylinder is a polygonal shape with the same cross section as the core, the number of corners is not particularly restricted. However, considering the ideal way to hold the writing instrument with a finger, the writing instrument is It is preferable to form the cross section of the outer shape of the shaft tube in a triangular shape having three side surfaces of the shaft tube because it can be held most easily and can be held correctly.

  According to the fifth configuration, the corner of the core is in contact with the writing surface by providing a convex portion or a concave portion on the outer periphery of the shaft cylinder so that the position of the corner of the core can be determined at the time of writing. Can be determined not only visually but also by tactile sensation, and the outer shape of the shaft tube can be freely selected.

  According to the sixth configuration, the tip opening is provided in front of the shaft cylinder, and the cross-sectional shape of the tip opening is formed to be the same shape and slightly larger than the core, thereby allowing the core to protrude from the inside of the shaft cylinder. Even when writing with a remaining core that has become shorter and can no longer be held by the chuck, the core does not rotate, and writing using the corners of the core is possible to the end.

  According to the present invention, since the cross section of the core is formed in a polygonal shape, writing at the corner where the core is pointed from the start of writing is possible, and even if writing continues, the handwriting is unlikely to be thick. It was possible to provide a mechanical pencil that can easily recognize that any corner of the core is in contact with the writing surface.

It is a side view which shows the mechanical pencil of a present Example. It is a perspective view of the core used for a present Example. It is sectional drawing which cut | disconnected the mechanical pencil of a present Example so that it might pass in parallel and with respect to the side surface of a shaft cylinder. It is an enlarged view of the AA cross section in FIG. It is an enlarged view of the BB cross section in FIG. It is a front view which shows the chuck | zipper of a mechanical pencil in a present Example. It is sectional drawing of the chuck | zipper in FIG. It is an end elevation which shows the rear end of the chuck | zipper in FIG. It is an end elevation which shows the front end of the mechanical pencil in a present Example. It is a perspective view which shows the state which writes in with the mechanical pencil in a present Example. It is a side view which shows the mechanical pencil of another Example. It is an enlarged view of CC section in FIG.

  Next, the mechanical pencil of the present embodiment will be described with reference to FIGS. 1 to 10, but the present invention is not limited to the following embodiments. In this embodiment, the case where the cross section of the core inserted into the mechanical pencil is a regular triangular prism formed into a regular triangle is illustrated. In addition, the side with the front opening of the mechanical pencil is expressed as the front, and the opposite side with the knob is expressed as the rear.

  FIG. 1 is a side view of the mechanical pencil 1 of this embodiment. The mechanical pencil 1 has a front opening 3 attached to the front portion of the shaft tube 2 and a knob 4 mounted from the rear of the shaft tube.

  As shown in FIG. 2, the core 5 used in the mechanical pencil 1 of the present embodiment is formed in a regular triangular prism having an end surface 5 a formed of a regular triangle, and side surfaces 5 b and corner portions 5 c are formed along the longitudinal direction of the core 5. have. In addition, since the corner | angular part 5c of a core will become easy to chip when it makes a perfect equilateral triangle, you may be slightly rounded.

  As shown in FIGS. 3 and 4, the shaft tube 2 has a front end step 2a formed at the front, and a locking recess 2b formed at the rear of the front end step 2a. Further, a front end inner hole 2c is formed at the front portion of the shaft cylinder 2, and a rotation stopper 2d protruding inward is provided behind the front end inner hole 2c. The outer shape of the shaft cylinder is an equilateral triangle which is the same as that of the core 5, and the outer shape of the shaft cylinder 2 is composed of side surfaces 2e and corner portions 2f extending in the longitudinal direction.

  Next, as shown in FIGS. 3 to 6, a chuck 6 is disposed in the tip inner hole 2 c of the shaft cylinder 2, and the chuck 6 has an elastic piece 6 a formed by dividing the front part into two. The elastic piece 6a is formed by a maximum diameter portion 6b having a front end formed in a substantially semicircular shape and a raised portion 6c provided on the outer periphery. Further, a core holding part 6d for holding the side surface 5b of the core 5 is provided inside the maximum diameter part 6b and the raised part 6c, and the shape of the core holding part 6d is vertical in a cross section passing through the corner part 5c of the core 5. It is formed in substantially the same concave shape as the half-divided shape, and an avoidance groove 6e is provided so that the corner 5c does not contact. The avoidance groove 6e can hold the core 5 without coming into contact with the corner 5f of the core that is easily chipped, so that it is possible to always write with the corner 5c having a sharp tip. The core 5 held by the core holding part 6d is configured such that the corner 2f of the shaft cylinder 2 is on the opposite side of the axis 5 with respect to the corner 5c.

  Further, as shown in FIGS. 7 and 8, a communication port 6f is formed at the rear portion of the chuck 6, and the cross-sectional shape of the rear end portion 6g of the communication port 6f is formed in a circular shape larger than the circumscribed circle of the core 5. The cross-sectional shape of the front end portion 6h of 6f is formed in a regular triangle that is the same shape as the core 5 and slightly larger than the core 5, and the cross-sectional shape of the connection port 6f is gradually reduced in a tapered shape from the rear end portion 6g to the front end portion 6h. In addition, the shape is changed from a circular shape to an equilateral triangle. Thereby, a plurality of guide portions 6i are formed on the inner surface of the communication port 6f. The rear end 6g of the communication port 6f is larger than the core 5 so that the core 5 can easily enter the communication port 6f. However, the communication port 6f has a size that allows only one core 5 to pass through. It is possible to prevent the cores 5 from being clogged in the communication port 6f by preventing the cores 5 from entering the communication port 6f at the same time. The clearance between the lead 5 and the communication port 6f at the front end 6h is less than 0.2 mm, and the lead 5 passing through the front end 6h is substantially unrotatable with respect to the chuck 6. Although not shown, the cross-sectional shape of the rear end 6g of the communication port 6f may be a polygonal shape larger than the core.

  Further, the chuck 6 is provided with a convex portion 6j extending in the longitudinal direction on the side surface, the concave portion 2g extending in the longitudinal direction is provided in the rotation stop portion 2d inside the shaft tube, and the convex portion 6j is inserted into the concave portion 2g. The chuck 6 and the shaft cylinder 2 are in sliding contact with each other so that they can slide in the front-rear direction and cannot rotate.

  Further, a fastener 7 is externally fitted to the raised portion 6 c of the chuck 6, and a flange 7 a is formed on the outer periphery of the fastener 7, so that play is allowed between the front end of the shaft tube and the rear stage portion 3 a of the tip 3. It is fitted. On the other hand, the radius of curvature of the maximum diameter portion 6b of the chuck 6 is formed to be larger than the inner hole 7b of the fastener 7, and the fastener 7 is prevented from slipping forward of the chuck beyond the maximum diameter portion 6b.

  Further, as shown in FIG. 3, a lead tank 8 is provided behind the chuck 6, a tip opening 8 a is formed at the front end of the lead tank 8, and a stepped protrusion 6 k is formed on the outer periphery of the rear part of the chuck 6. The lead tank 8 is press-fitted into and fitted into the tip opening 8a. Further, a storage portion 8b capable of storing a plurality of spare cores 5 is provided inside the core tank 8, and an outer stage 8c is formed on the outer periphery of the rear portion. A spring 9 is stretched between the outer stage 8c of the core tank 8 and the rear inner stage 2h formed in the inner hole of the shaft cylinder 2 with an attachment load of about 500 g, and the core tank 8, the chuck 6 and the fastener 7 are stretched. And bounce back. On the other hand, the chuck 6, which is ejected rearward, is supported by the flange portion 7 a of the fastener 7 that is externally fitted against the tip of the shaft tube 2. Further, a step portion 8c is formed inside the rear portion of the lead tank 8, and an eraser 10 is detachably attached to the step portion 8c.

  In addition, a rear collar 8d is provided on the outer periphery of the rear part of the core tank 8, a circumferential groove 8e is formed behind the rear collar 8d, and a locking projection 4a projecting inward is formed inside the front end of the knob 4. The knob 4 is detachably attached to the core tank 8 by engaging the locking projection 4a with the circumferential groove 8e of the core tank.

  Further, as shown in FIGS. 3, 5, and 9, the tip 3 disposed at the tip of the shaft tube has an inner hole formed in a step shape, and a core is placed on the front step portion 3 b of the inner hole with an appropriate force. A rubber core holder 11 to be held is mounted. Further, a locking projection 3c that protrudes inward is provided at the rear end of the inner hole of the tip 3 and the tip 3 is engaged with the locking projection 3c and the locking recess 2b of the shaft tube 2. The shaft cylinder 2 is detachably mounted. Further, a front end 3d formed as a regular triangle slightly larger than the cross section of the core 5 is provided at the front end of the front end 3, and the front end 3d is aligned with the position of the corner 5c of the core held by the core holding portion 6d. A corner 5c of the core is formed on the opposite side of the axis M with respect to the corner 2f of the tube 2. In addition, by forming the gap between the lead 5 and the tip end 3d to be 0.2 mm or less, the lead 5 is supported by the tip end 3d without shaking at the time of writing, and the lead fed out by the chuck 6 with a proper gap is smooth. It is possible to pass through the tip 3d. Further, the outer shape of the front opening 3 is formed in a triangular pyramid shape having a triangular rear end in accordance with the shaft tube 2.

  Here, when the mechanical pencil 1 of the present embodiment knocks the knob 4 and feeds the lead 5, the lead 5 entering the contact port 6 f at the rear of the chuck from the storage part 8 b of the lead tank 8 is connected to the corner part 5 c. When it advances while rotating in sliding contact with the guide portion 6i formed on the inner surface of 6f and passes through the connection port 6f, the position of the corner portion 5c of the core is the axis M with respect to the corner portion 2f of the shaft tube 2. Move to the opposite position across the. As a result, the position of the side surface 5b of the core 5 reaching the core holding part 6d is completely coincident with the core holding part 6d formed in a concave shape, so that the core 5 can be held by the core holding part 6d as it is. . For this reason, when hold | maintaining the core 5, damage, such as a corner | angular part 5c missing, does not arise. Furthermore, the core 5 fed forward by the chuck 6 by knocking the knob 4 passes through the core holder 11 and reaches the distal end port 3d of the front end 3, and the position of the outer shape of the core 5 like the core holding portion. And the position of the inner shape of the tip 3d coincide with each other so that it smoothly passes through the tip 3d and protrudes forward. Further, since the tip opening 3d is formed in an equilateral triangle having substantially the same shape as the lead 5, the lead 5 cannot rotate with respect to the tip opening 3d, and the lead 5 becomes shorter by continuing writing although not shown. Even if the core 5 cannot be held by the chuck, the core 5 does not rotate during writing, and writing by the corner portion 5c of the core can be continued until the end of the remaining core.

Further, when writing with the mechanical pencil of the present embodiment, as shown in FIG. 10, the corner 2f of the shaft tube is on the opposite side of the axis M with respect to the writing surface H (upward in FIG. 10). By holding the side surface 2e of the shaft cylinder with the thumb, forefinger, and middle finger, the corner 5c of the core comes into contact with the writing surface H, and writing with a sharp tip from the beginning of writing can be performed. In addition, when writing is continued, the tip of the lead 5 is shaved and the handwriting becomes thick, the shaft 2 is rotated with the corner 2f of the shaft 2 as a mark, and the lead contacting the writing surface H By moving the corner 5c to the other corner 5d, it is possible to easily continue writing with a sharp tip.
In the case where the outer shape of the shaft tube 2 is a regular triangle as in this embodiment, when the shaft tube 2 is correctly held by the thumb, forefinger, and middle finger, the corner 2f naturally faces upward in FIG. Since the part 5c contacts the writing surface H, it is easy to use and preferable.

  Next, FIG.11 and FIG.12 shows the mechanical pencil 101 of another Example. The mechanical pencil 101 has a circular outer periphery of the shaft tube 102, and a convex shape shown in FIG. 12A on the outer peripheral surface on the opposite side of the shaft tube 102 with respect to the corner portion 5c of the core. The portion 102a or the concave portion 102c shown in FIG. 12B is formed to determine the position of the corner 5c of the core. Further, the front end 103 is formed in a conical shape whose outer end is narrowed in accordance with the shaft tube 102. The other components other than the outer shape of the shaft tube 102 and the tip 103 are the same as those in the present embodiment.

  When writing with the mechanical pencil 101 of another embodiment, not only the position of the corner 5c of the core is visually determined, but also the tactile sensation can be achieved by forming the convex portion 102a and the concave upper portion 102b at the position where the finger hits. Since it can be confirmed whether the corner 5c of the core is in contact with the writing surface, the outer shape of the shaft tube can be freely configured.

  The mechanical pencil of the present invention is not limited to the diameter and color of the writing core, and can be widely used as a mechanical pencil.

1 ... mechanical pencil,
2 ... shaft cylinder, 2d ... rotation stopper,
3 ... tip opening, 3d ... tip opening,
4 ... Knob,
5 ... Core, 5b ... Side, 5c ... Corner,
6 ... chuck, 6a ... elastic piece, 6d ... core holding part, 6f ... communication port, 6i ... guide part,
7 ... Fasteners,
8 ... Core tank,
9 ... Spring,
10 ... Eraser,
11 ... Core holder,
H ... Writing surface,
M ... Axis center.

Claims (6)

A mechanical pencil that feeds a lead having a polygonal cross section and side faces and corners by moving the chuck arranged in the shaft cylinder back and forth, so that the lead cannot be rotated on the chuck. A lead holding portion is formed, and a rotation stop portion is provided in the shaft tube to prevent the chuck from rotating with respect to the shaft tube while the chuck holds the core, and the core holding portion A plurality of guide portions with which the core is slidably contacted behind are formed, and when the core passes between the guide portions forward, the outer shape of the core can be held by the core holding portion. The position of the corner of the core is fixed with respect to the shaft cylinder by holding the core with the core holding portion in the direction of the core, and the corner of the core is written on the shaft cylinder at the time of writing. For recognizing that the part is in contact with the writing surface Pencil was characterized in that a discriminating means. A plurality of elastic pieces are formed at the front portion of the chuck, and the elastic holding piece is provided with the core holding portion formed in a concave shape in accordance with the outer shape of the core so that the core holding portion and the side surface of the core are in contact with each other. The mechanical pencil according to claim 1. A communication port through which the core passes is provided behind the chuck, and a rear end portion of the communication port is larger than the core and is formed in a circular shape or a polygonal shape through which only one core can pass, A front end portion of the connection port is formed in a polygonal shape that is the same shape and slightly larger than the core, and a cross-section of the connection port is formed by gradually changing from the rear end portion to the front end portion in a tapered shape, 3. The mechanical pencil according to claim 1, wherein a plurality of inner walls formed inward are used as the guide portion. The outer shape of the shaft cylinder is formed in the same polygonal shape as the core, and a side surface and a corner portion are provided along the shaft center, and the side of the core is opposite to the corner portion of the shaft tube with the shaft center interposed therebetween. Recognizing a state in which the corner portion of the core is in contact with the writing surface at the corner portion of the shaft cylinder by forming the core holding portion of the chuck so that the corner portion is positioned and holding the core. The mechanical pencil according to any one of claims 1 to 3, wherein the discriminating means is configured. A convex portion or a concave portion is formed on the outer diameter of the shaft cylinder, and the core of the chuck is positioned so that the corner portion of the core is located on the opposite side of the axial center with respect to the convex portion or the concave portion. 2. The discriminating means for recognizing a state in which a corner portion of the core is in contact with a writing surface at the convex portion or the concave portion by forming a holding portion to hold the core. 4. The mechanical pencil according to any one of items 3 to 3. 6. The tip according to claim 1, wherein a tip opening through which the core can pass is formed in front of the shaft cylinder, and a cross section of the tip opening is formed in a polygon having the same shape and slightly larger than the core. mechanical pencil.

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