JP2007168362A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which keeps a lead feeding mechanism arranged in a barrel, and a sliding member allowing a lead to protrude/recede arranged at the leading end of the barrel in such a manner as to be movable forward and backward, and enables the lead to be properly fed without being curved. <P>SOLUTION: The mechanical pencil keeps the lead feeding mechanism arranged in the barrel, the sliding member allowing the lead to protrude/recede arranged at the leading end of the barrel in such a manner as to be movable forward and backward, a tip member fixed ahead of the lead feeding mechanism, and the sliding member slidably arranged on the tip member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mechanical pencil in which a core feeding mechanism is disposed in a shaft cylinder, and a slide member in which a core protrudes and retracts is disposed at the tip of the shaft cylinder so as to be movable back and forth.

In a conventional writing instrument, a lead chuck mechanism is arranged inside an outer cylinder, a sleeve is fitted to the tip of the lead chuck mechanism, and a fitting cylinder in which an elastic body is interposed in the sleeve to prevent retraction of the core. Mechanical pencils that can be moved back and forth are known.
No. 53-136243 (No. 53-136243)

However, in the above prior art, since the sleeve is attached to the tip of the lead chuck mechanism at a small distance and in a fitted state, the attachment to the lead chuck mechanism is extremely unstable. It had become. That is, the lead chuck mechanism and the central axis of the sleeve are likely to be displaced during an operation of extending the lead or by an unexpected external force.
When the center axis of the lead chuck mechanism and the sleeve is shifted, the center axis of the fitting cylinder inscribed in the sleeve is also shifted, and as a result, the core is bent and the core cannot be fed out. Otherwise, there was a risk that the lead could be caught in the sleeve and broken during the lead feeding operation.

  The present invention is a mechanical pencil in which a core feeding mechanism is arranged in a shaft cylinder, and a slide member in which a core protrudes and retracts is arranged at the tip of the shaft cylinder so as to be movable back and forth, and in front of the core feeding mechanism. The gist is that the tip member is fixed and the slide member is slidably disposed on the tip member.

  The present invention is a mechanical pencil in which a core feeding mechanism is arranged in a shaft cylinder, and a slide member in which a core protrudes and retracts is arranged at the tip of the shaft cylinder so as to be movable back and forth, and in front of the core feeding mechanism. Since the tip member is fixed and the slide member is slidably arranged on the tip member, the lead member can be fed out without being bent.

A first example will be described with reference to FIGS. In the figure, the upper part is called rear and the lower part is called front. The shaft cylinder 1 is composed of a rear shaft 29 and a front shaft 30, and a writing body such as a mechanical pencil lead feeding mechanism and a ballpoint pen refill is accommodated in the shaft cylinder 1. A core feeding mechanism 2 is built in the shaft cylinder 1 in this example. The lead feeding mechanism 2 is fixed to the front of the lead tank 3 via a joint 4, and includes a chuck body 5 for gripping and releasing the lead, a chuck ring 6 for opening and closing the chuck body 5, and the lead tanks. 3 and a chuck spring 7 such as a coil spring that urges the chuck body 5 and the like backward. An eraser 9 and a knock cap 10 are detachably attached to the rear of the core tank 3 so as to cover the eraser 9 and the eraser 9 via an eraser receiver 8. Reference numeral 11 denotes a washer interposed between the eraser receiver 8 and the eraser 9 and substantially press-fits the eraser 9.
An intermediate screw 13 is attached in front of the core feeding mechanism 2, and the core feeding mechanism 2 is fixed to the front shaft 30 by the middle screw 13. More specifically, the front shaft 30 includes a middle shaft 30a and a tip portion 30b, and the middle shaft 30a and the tip portion 30b are detachably fixed by screwing. Further, the core feeding mechanism 2 is fixed to the front shaft 30 by sandwiching the flange portion 13a formed on the middle screw 13 of the core feeding mechanism 2 between the middle shaft 30a and the tip portion 30b. In addition, a metal tip member 14 is detachably fixed to the front of the middle screw 13 by screwing, and the tip member 14 has a core detent made of a rubber-like elastic body that prevents the core from retreating. A metal slide member 16 having a member 15 provided therein is disposed. However, the core detent member 15 provides a frictional resistance against sliding between the tip member 14 and the slide member 16. The frictional resistance of the slide member 16 with respect to the tip member 14 is set larger than the frictional resistance of the core with respect to the core detent member 15. Further, a reduced diameter portion 14a is formed on the front inner surface of the tip member 14, and a large diameter portion 14b is formed on the rear inner surface of the small diameter portion 14a. The small diameter portion 14a and the large diameter portion 14b are formed. Are connected and integrally formed, but may be formed of separate members and connected to each other. However, it is desirable to form them integrally in order to match the central axes of each other. Incidentally, the outer peripheral portion of the slide member 16 is in sliding contact with the small diameter portion 14a, while the outer peripheral portion of the core detent member 15 is in sliding contact with the large diameter portion 14b. The detent member 15 provides frictional resistance to the tip member 14.
Furthermore, in this example, the tip member 14 and the slide member 16 that slides in the tip member 14 are both made of a metal material, but may be made of a resin material or different from each other. In this example, an O-ring 42 made of elastic rubber is interposed at the threaded portion between the intermediate screw 13 and the tip member 14. By interposing the O-ring 42, loosening of the intermediate screw 13 and the tip member 14 is prevented, but by making the tip member 14 detachable from the intermediate screw 13, each of them is intentionally separated. The slide member 16 can be removed, which makes it possible to perform repair work in the event that the core is broken in the tip member 14 by any chance.

  Reference numeral 17 denotes a transparent resin guide member that is press-fitted into the inner surface of the front portion of the tip portion 30b. At the rear of the guide member 17, slits 17a are formed at two opposite positions. . It is a slit for facilitating insertion of the guide member 17 into the tip portion 30b, and is inserted into the tip portion 30b in a state where the rear portion of the guide member 17 is bent in the inner diameter direction. Although the pressure input is slightly reduced, it is possible to obtain a pressure input that is stable in the long run. And the front member 14 is located in the state which contact | abutted on the back inner surface of the guide member 17. FIG. In other words, the guide member 17 and the slide member 16 are aligned with each other by bringing the tip member 14 into circumferential contact with the guide member 17. In addition, since the tip member 14 is screwed and fixed to the core feeding mechanism 2 via the middle screw 13 as described above, the leading member 14 matches the center axis of the guide member 17 as well as the core feeding mechanism 2. Yes. And, when the core feeding mechanism 2 (medium screw 13), the tip member 14 and the central axis of the slide member 16 are accurately matched, the core fed out from the chuck body 5 is not curved, It is guided accurately by the core detent member 15 and protrudes from the tip of the slide member 16.

The front inner surface of the guide member 17 is a small diameter portion 17b, while the rear inner surface where the slit 17a is formed is a large diameter portion 17c. The outer shape of the tip member 14 also has an outer diameter equivalent to that of the small diameter portion 17b and the large diameter portion 17c of the guide member 17. That is, two places with different diameters are placed in contact with each other. While making it easy to assemble each other member, the circumferential contact force after the assembly is improved.
The tip portion 30b may be formed of a metal material. In this example, the tip portion 30b is formed of a resin material, and the surface of the resin is plated (plating layer 40). You may form the coating layer which apply | coated etc. However, the plating (metal) concentrates on the corners due to the plating process, and the metal bulges due to the metal concentration (the bulging portion 40a), and the bulging causes the inner diameter of the protruding hole of the tip portion 30b to be unsatisfactory. In order to be accurate, the material of the guide member 17 to be inserted into the tip of the tip portion 30b is a resin material. In other words, the bulging amount of the bulged portion is absorbed using the action of elastic deformation of the resin guide member 17. Of course, the guide member 17 is not plated, and an accurate inner diameter of the protruding hole is ensured. In this example, the guide member 17 is formed by injection molding, but may be formed by means such as cutting or punching.
However, if the plating layer 40 is not applied, or if the plating layer 40 can be accurately applied in a uniform state, and if it is not necessary in terms of design, the guide seat 17 is not necessarily provided. It is not necessary (see FIG. 10).

A cylindrical body 18 that cannot be rotated with respect to the rear axis 29 but can be moved back and forth is attached to an intermediate portion in the longitudinal direction of the rear axis 29 of the shaft cylinder 1. An abutting handle 19 is provided. A gripping portion 20 is provided in front of the inter-finger contact handle 19 and the cylindrical body 18. The inter-finger contact handle 19 is attached so as to straddle the cylinder 18 and is attached so as to be rotatable with respect to the direction perpendicular to the axis of the shaft cylinder 1. More specifically, the finger contact pattern 19 includes a bifurcated leg portion 19a and a support portion 19b connecting the leg portion 19a, and the leg portion 19a rotates to the side of the cylindrical body 18. It is attached freely.
Here, the operation of the inter-finger contact pattern 19 will be described. 6 and 7, when the grip 20 is gripped so as to be surrounded by three points of the thumb, the index finger, and the middle finger, the inter-finger contact handle 19 is located between the thumb and the index finger, and as a result, The entire finger contact pattern 19 is supported by the palm. This support force assists the writing load, and reduces the burden on the finger of the grip portion 20.
The inter-finger contact 9 is attached so as to be rotatable with respect to the direction perpendicular to the axis of the shaft cylinder 1 as described above, but the rotation angle can be set as appropriate. The example shown in FIGS. 6 to 9 is a state in which the angle is expanded to the maximum, and the angle adjustment member 41 that is movably disposed on the side wall of the shaft tube 1 is advanced to reduce the angle. be able to. In other words, the crotch portion of the bifurcated leg portion 19a comes into contact with the surface of the angle adjusting member 41, and the rotation operation with respect to the shaft tube 1 is restricted.
In addition, although the said finger | toe contact handle 19 and the holding part 20 are comprised by the cylinder 18 and the axial cylinder 1, and you may form integrally. The finger contact pattern 19 and the gripping member 20 are formed of an elastic member such as a thermoplastic elastomer, silicon, or nitrile butadiene rubber in order to obtain an anti-slip effect, but a hard material such as polycarbonate, Cover the surface of the finger contact pattern 19 or the gripping member 20 formed of acrylonitrile / butadiene / styrene resin, polyacetal, polyamide, polypropylene, polyethylene terephthalate, etc., or partially dispose the elastic member. Alternatively, a coating material that can provide an anti-slip effect may be applied and cured. In particular, since there is a concern that a relatively large force is applied to the finger contact pattern 19, it is formed of a hard material such as metal, and an elastic member having a non-slip function is attached to the surface thereof. Alternatively, it may be molded by the method of insert molding, or the surface of the inter-finger contact pattern 19 may be subjected to fine concavo-convex knurling.

Next, an example in which the inter-finger contact pattern 19 can be stored in the cylinder 18 (shaft cylinder 1) is shown in FIG. The inter-finger contact pattern 19 is attached so as to straddle the cylinder 18 and is attached so as to be rotatable with respect to a direction perpendicular to the axis of the shaft cylinder 1.
The finger contact pattern 19 is expanded from the cylindrical body 18 (shaft cylinder 1) as shown in FIGS. 6 and 7 when in use, but is rotated by a rotating support column 21 to form a cylindrical body. 18 can be stored. That is, by rotating the finger contact pattern 19 with respect to the direction perpendicular to the axis of the shaft tube 1, the finger contact pattern 19 is expanded from the shaft tube 1 or closed (stored). Is possible. In this example, a V-shaped concavo-convex portion is provided on the inner surface of the tip of the leg portion 19 a of the finger contact pattern 19, and the concavo-convex portion is engaged with a continuous mountain-shaped engaging portion formed on the cylindrical body 18. I am letting. By engaging the concavo-convex part with the engaging part in stages, the inter-finger contact pattern 19 can be held in the stored state.

  Next, the moving means with respect to the longitudinal direction of the shaft cylinder 1 of the inter-finger contact pattern 19 (cylinder 18) will be described. A switch 25 is disposed on the side wall of the cylindrical body 18, and the switch 25 can be engaged with and disengaged from the shaft cylinder 1. By utilizing the engagement / disengagement action of the switch 25 and the shaft cylinder 1, the front / rear positioning of the cylinder 18 with respect to the shaft cylinder 1 is possible. And by making the cylinder 18 movable with respect to the shaft cylinder 1, the finger contact pattern 19 can also be moved, so that it can be used satisfactorily from a user with a large hand to a user with a small hand. become.

Next, the shaft cylinder 1 will be described in detail. The shaft cylinder 1 is composed of the rear shaft 29 that covers the cylindrical body 18 having the finger contact pattern 19 as described above and the front shaft 30 (middle shaft 30a) on which the grip portion 20 is fitted. The rear shaft 29 and the front shaft 30 are coupled so as to be rotatable with respect to the circumferential direction of the axis. In other words, the rear shaft 29 having the inter-finger contact pattern 19 can rotate relative to the front shaft 30. A flat portion 29a is formed on the surface of the rear shaft 29, and the flat portion formed on the inner surface of the cylindrical body 18 is in contact with the flat portion 29a. Thereby, relative rotation with respect to the rear shaft 29 of the cylinder 18 is prevented. An engagement recess is formed on the inner surface of the rear shaft 29, while an engagement collar portion that engages with the engagement recess is formed at the rear end of the front shaft 30 (medium shaft 30 a). . The engagement between the engagement concave portion and the engagement flange portion is given a rotational frictional resistance against the relative rotation of the rear shaft 29 and the front shaft 30 by slightly increasing the engagement force. That is, the rear shaft 29 and the front shaft 30 do not rotate relative to each other unless a certain load is applied.
Further, in this example, a resilient member 31 such as an O-ring made of a rubber-like elastic body is disposed between the rear shaft 29 and the front shaft 30 and urges each other in the radial direction. In other words, the elastic members 31 are biased in directions away from each other, and the rotational friction resistance is imparted to the rotation of the rear shaft 29 and the front shaft 30 by this biasing force. The rotational friction resistance between the rear shaft 29 and the front shaft 30 can be easily changed and set by changing the resilient force of the resilient member 31. In this example, the rotational torque is set to 70 gf. A rotational action is obtained when .about.150 gf is applied. In this example, the elastic member 31 is positioned inside the rear shaft 29 in order to improve the appearance. Specifically, a large-diameter space portion 32 is formed on the front inner surface of the rear shaft 29, and the elastic member 31 is disposed in the large-diameter space portion 32. However, in consideration of interest, the elastic member 31 may be disposed in a state of being exposed between the front end portion of the rear shaft 29 and the intermediate flange portion 33 of the front shaft 30. By rotating the rear shaft 29 and the front shaft 30 relative to each other, for example, when the core is partially reduced during writing, the rear shaft 29 is gripped, that is, writing is performed. By rotating the front shaft 30 while maintaining the state, it is possible to eliminate the reduction of the core.

Reference numeral 36 denotes a clip configured and attached as a separate member to the rear shaft 29, but may be integrally formed. The clip 36 is provided at a position opposite to the inter-finger contact pattern 19. It is provided in a part that does not get in the way of writing.
The operation will be described. When it is desired to rotate the rear shaft 29 (cylindrical body 18) relative to the front shaft 30, the left hand may hold the front shaft 30 and the right hand may hold the rear shaft 29 and rotate relatively. It can also be rotated while maintaining the written state. That is, since the inter-finger contact pattern 19 is sandwiched between the thumb and the index finger, the rotation of the rear shaft 29 is prevented. Here, if a rotating action is applied to the gripping member 20 by the thumb, index finger, and middle finger gripping the gripping portion 20, the front shaft 30 is rotated. By the rotation of the front shaft 30, the lead feeding mechanism (writing body) 2 fixed to the front shaft also rotates.

The front external view which shows the 1st example of this invention. The side view of FIG. The longitudinal cross-sectional view of FIG. (A) The principal part enlarged view of FIG. (B) Enlarged view of essential parts of FIG. XX sectional drawing of FIG. The front external view which act | operated the finger contact pattern. The side view of FIG. The longitudinal cross-sectional view of FIG. The principal part enlarged view of FIG. The principal part longitudinal cross-sectional view which shows a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Center feeding mechanism 3 Core tank 4 Joint 5 Chuck body 6 Chuck ring 7 Chuck spring 8 Eraser receiver 9 Eraser 10 Knock cap 11 Washer 13 Medium screw 14 Tip member 15 Core detent member 16 Slide member 17 Core guide member 18 Cylindrical body 19 Finger contact pattern 20 Grip member 21 Rotating support column 25 Switch 29 Rear shaft 30 Front shaft 31 Resilient member 32 Large diameter space portion 33 Intermediate collar 40 Plating layer 41 Angle adjusting member 42 O-ring

Claims (4)

A mechanical pencil is provided in the shaft cylinder, and a slide member in which the core protrudes and retracts is arranged at the tip of the shaft cylinder so as to be movable back and forth, and the tip member is fixed in front of the core feeding mechanism. In addition, the mechanical pencil is characterized in that the slide member is slidably disposed on the tip member. The mechanical pencil according to claim 1, wherein a plating layer or a paint layer is formed on a front surface of the shaft cylinder. The mechanical pencil according to claim 1 or 2, wherein a guide member is disposed between the shaft tube and the tip member, and the guide member is fixed to the shaft tube. The mechanical pencil according to any one of claims 1 to 3, wherein sliding resistance is imparted in sliding between the slide member and the tip member.

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