JPH07251595A - Knock type mechanical pencil - Google Patents

Abstract

PURPOSE:To provide a return spring with multiple functions which can eliminate shaking in the axial direction as what is called scooping phenomenon is not generated at the time of knocking and absorb excessive writing pressure by cushioning function and adjust the unevenness among parts. CONSTITUTION:A knock type mechanical pencil comprises a shaft main body consisting of a front shaft 1 and a rear shaft 2, a refill tank 6 provided slidably on the shaft main body, chuck components 8 and 9 fixed on an end of the refill tank 6, chuck springs 13 wound on the chuck components 8 and 9 and a chuck ring 8 fitted movably on a suck section of the chuck 9. Also the mechanical pencil comprises an inner cylinder 5 installed through the refill tank 6 and a cap 10, a fitting cylinder 3 mounted on the rear section of the inner cylinder 5, a sleeve 11 disposed in the cap 10, a return spring 14 interposed between the sleeve 11 and the inner cylinder 5 and knock components 15-18 disposed at the rear end of the refill tank 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil, and more particularly to a knock type mechanical pencil whose return spring has multiple functions.

[0002]

2. Description of the Related Art Conventionally, as a writing instrument of this type, a knock type mechanical pencil as shown in FIG. 9 has been proposed. That is, the lead tank 32 is slidably inserted into the barrel 31, and the chuck joint 3 is attached to the tip of the lead tank 32.
3 is press-fitted and fixed, the chuck 34 is attached, and the chuck ring 35 is loosely fitted on the chuck tip.
A chuck spring 37 is provided between the chuck joint 33 and the sleeve 36, and a return spring 38 is wound between the outer circumference of the sleeve 36 and the step formed on the inner circumference of the barrel 31. At the tip of the sleeve 36, a tip plastic 39 having a tip end bulging like an arrow is provided, and an internal mechanism such as a lead tank 32 is provided between the tip plastic 39 and the tip end opening of the axle cylinder 31. A stopper piece 40 is fitted so as not to fall off the shaft cylinder 31 incorporated in the. However, according to this conventional mechanical pencil, the return spring 38 eliminates the rattling of the internal mechanism such as the lead tank 32 in the axial direction. As a result, the stopper piece 40 causes rattling in the axial direction due to a so-called hiccup phenomenon in which the stopper piece 40 projects in and out of the front end opening of the shaft cylinder 31.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, eliminates the so-called hiccup phenomenon at the time of knocking, has no axial rattling, and absorbs excessive writing pressure due to the cushion function. It is an object of the present invention to provide a knock-type mechanical pencil in which a return spring has a multi-function capable of adjusting the variation between parts.

[0004]

To achieve the above object, according to the present invention, a shaft body including a front shaft and a rear shaft,
A core tank slidably provided on the shaft body, chuck means fixed to the tip of the core tank, a chuck spring wound around the chuck means, and a chuck of the chuck means loosely fitted. A chuck ring, an inner cylinder provided via the core tank and the cap means, a fitting cylinder attached to the rear portion of the inner cylinder, a sleeve provided in the cap means, the sleeve and the inner cylinder. A knock type mechanical pencil including a return spring interposed between the core tank and a knock means provided at the rear end of the lead tank is obtained.

Further, a shaft body composed of a front shaft and a rear shaft, a lead tank slidably provided on the shaft body, a chuck means fixed to a front end of the lead tank, and a chuck means A wound chuck spring, a chuck ring loosely fitted to the chuck of chuck means, an inner cylinder provided via the core tank and the mouthpiece means, and a fitting cylinder attached to the rear part of the inner cylinder. A knock type mechanical pencil including a sleeve provided in the mouthpiece means, a return spring provided at a rear end of the inner cylinder, and a knock means provided at a rear end of the lead tank is obtained. To be

[0006]

[Function] When the knock portion at the rear end of the mechanical pencil is knocked, the lead tank is advanced against the biasing force of the chuck spring, and the chuck provided at the tip of the lead tank is also advanced and the lead is sent out for writing. Becomes Note that if you write in this state, the return spring will not absorb the excessive writing pressure when excessive writing pressure is applied, and the core will not break. The action of the return spring prevents the tip pipe etc. from rattling in the axial direction. Further, even if there are variations in the axial direction among the parts such as the wick tank, adjustment can be performed by the action of the return spring.

[0007]

1 shows an embodiment of a knock type mechanical pencil of the present invention, in which a front shaft 1 and a rear shaft 2 are connected by a fitting cylinder 3 inside. That is, the front end of the fitting cylinder 3 is press-fitted and fixed inside the front shaft 1 and has a large diameter portion at a portion corresponding to the inner peripheral portion of the rear shaft 2, and the rear shaft 2 It is press-fitted inside. At the rear end of the fitting cylinder 3, a connecting cylinder 4 is fixed by an engaging portion 4a, and an inner cylinder 5 is provided in contact with the front surface of a flange 4b that extends inward of the connecting cylinder 4. . A core tank 6 is slidably inserted into the inner cylinder 5, and a chuck joint 7 is fixedly provided at the tip of the core tank 6. A chuck 9 in which a chuck ring 8 is loosely fitted is press-fitted into the tip of the chuck joint 7. Further, a mouthpiece 10 is provided on the inner side of the tip of the inner cylinder 5.
A sleeve 11 is inserted inside the rear part, while a slider 12 having a tip pipe 12a at the front part and having a bulky packing 12b inserted inside the rear part is slidably provided.

A chuck spring 13 is interposed between a stopper portion 11a formed on the front portion of the sleeve 11 and the front end of the chuck joint 7, and the rear end of the sleeve 11 and the inner cylinder 5 are connected. A return spring 14 is interposed between the locking portion 5i and the locking portion 5i. On the other hand, an eraser cradle 15 is detachably fitted to the rear end of the lead tank 6, an eraser 17 having a metal jacket 16 attached is fitted to the eraser cradle 15, and an eraser cap 18 is provided. It is covered and the function as a knock part is given. In the figure, reference numeral 19 is the front shaft 1
Is a front tool screwed to the inner side of the front portion of, and 20 is a decorative ring interposed between the front shaft 1 and the rear shaft 2.

Next, the operation of the mechanical pencil according to the above embodiment will be described. First, when the eraser cap 18 is knocked, the lead tank 6 is advanced through the rubber receiving base 15 together with the chuck 9 holding the lead 9 against the backward biasing force of the chuck spring 13. When the chuck 9 is advanced to some extent, the chuck ring 8 loosely fitted to the chuck 9 comes into contact with the stepped portion 11a of the die 11 and is removed from the chuck portion to release the chuck portion. When the chuck 9 is further advanced, its tip pushes out the rear end of the slider 12, so that the tip pipe 12a is projected from the tip of the tip tool 19 to be in a writing state. If the lead is worn during writing, the lead may be knocked out again to feed the lead. Further, since the return spring 14 is interposed between the sleeve 11 and the inner cylinder 5 as described above, even if excessive writing pressure is applied during writing, the return spring 14
Also functions as a cushion spring, so the core is not easily broken.

FIG. 2 shows another embodiment of the present invention in which the connecting cylinder 4 in the above embodiment is eliminated to reduce the number of parts. That is, as shown in FIG.
The engagement groove 3a is formed in the rear portion, and a pair of protrusions is formed on the outer periphery of the rear portion of the inner cylinder 5 in correspondence therewith for press-fit engagement. More specifically, the shape as shown in FIG. 3A, that is, the inlet of the engagement groove 3a of the fitting cylinder 3 is formed in the inclined portion 3b which widens rearward, and the projection of the inner cylinder 5 is When 5a is pushed in from the rear, it is guided by the inclined portion 3b and easily engaged. As shown in FIG. 3B, once engaged, the engagement is not easily released due to the shape of the inlet of the engagement groove 3a and the projection 5a of the inner cylinder 5. The operation of this embodiment is similar to that of the above embodiment.

FIG. 4 shows another example of the engagement relationship between the fitting cylinder 3 and the inner cylinder 5 of FIG. 3, in which case the fitting cylinder 3 is attached to the fitting cylinder 3 as shown in FIG. 4 (A). A plurality of locking holes 3c are formed, and a split groove 3d is formed in the axial direction between the locking holes 3c. Then, a protrusion 5a having an inclined portion 5b for facilitating insertion at the front portion and an upright portion 5c at the rear portion is provided on the outer periphery of the inner cylinder 5. In such a structure, when the protrusion 5a of the inner cylinder 5 is press-fitted from the rear of the fitting cylinder 3, the split groove 3 is formed.
By the action of d, the inner diameter of the fitting cylinder 3 is expanded, and FIG.
It can be easily press-fitted and engaged as shown in (B).

FIG. 5 shows still another example of the engagement relationship between the fitting cylinder 3 and the inner cylinder 5. In this case, the fitting cylinder 3 is formed with a locking hole 3e spaced from the rear end. The slits 5d are formed in the axial direction on both sides of the protrusion 5a formed on the other inner cylinder 5. In such a structure, when the projection 5a of the inner cylinder 5 is press-fitted from the rear of the fitting cylinder 3, the projection 5a comes into contact with the rear end edge of the fitting cylinder 3 and the slits 5d are axially formed on both sides of the projection 5a. The projection 5a sinks inward by the action of, so that it can be easily engaged with the locking hole 3e.

FIG. 6 shows another example of the engagement relationship between the fitting cylinder 3 and the inner cylinder 5. In this case, a split groove 3f is formed at the rear end of the fitting cylinder 3 and the rear end portion is formed. A locking portion 3g bent slightly inward is provided. On the other hand, on the outer circumference of the inner cylinder 3, there is an inclined portion 5b for facilitating the insertion in the front portion and the rear portion is the upright portion 5.
The protrusion 3a having c is provided and the split groove 3f is formed. In such a structure, when the protrusion 5a of the inner cylinder 5 is press-fitted from the rear of the fitting cylinder 3 as shown in FIG.
It can be easily engaged as in (B). Further, FIG. 7 shows an assembly structure which does not depend on the engagement between the fitting cylinder 3 and the inner cylinder 5, and the fitting cylinder 3 and the inner cylinder 5 are coupled by the screwing portion 3h.

FIG. 8 shows still another embodiment of the present invention. According to this embodiment, the return spring 14 is locked so that the rear end of the sleeve 11 and the inner cylinder 5 project inward as shown in FIG. Instead of being interposed between the portion 5a and the portion 5a, it is interposed between the rear end of the inner cylinder 5 and the connecting cylinder 4. The rear end of the front sleeve 11 is in contact with the step of the thick portion of the inner cylinder 5. Therefore, when excessive writing pressure is applied, unlike the above-described embodiment, the entire internal mechanism simply moves backward.

[0015]

As the so-called hiccup phenomenon does not occur when knocking, there is no backlash in the axial direction, it is possible to absorb excessive writing pressure due to the cushion function, and it is also possible to adjust the variation between parts. It is possible to add to the return spring.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a knock type mechanical pencil of the present invention.

FIG. 2 is a sectional view showing another embodiment of the knock type mechanical pencil of the present invention.

FIG. 3 is an explanatory view showing an engagement relationship between a fitting cylinder and an inner cylinder of FIG.

FIG. 4 is an explanatory diagram showing another example of the engagement relationship between the fitting cylinder and the inner cylinder of FIG.

FIG. 5 is an explanatory view showing still another example of the engagement relationship between the fitting cylinder and the inner cylinder of FIG.

FIG. 6 is an explanatory view showing still another example of the engagement relationship between the fitting cylinder and the inner cylinder of FIG.

FIG. 7 is an explanatory diagram showing still another example of the engagement relationship between the fitting cylinder and the inner cylinder of FIG.

FIG. 8 is a sectional view showing still another embodiment of the knock type mechanical pencil of the present invention.

FIG. 9 is a cross-sectional view showing a conventional knock type mechanical pencil.

[Explanation of symbols]

 1 Front Axis 2 Rear Axis 3 Fitting Tube 5 Inner Tube 6 Core Tank 8 Chuck Ring 9 Chuck 10 Clasp 11 Sleeve 13 Chuck Spring 14 Return Spring

Claims (10)

[Claims] 1. A shaft main body comprising a front shaft and a rear shaft, a core tank slidably provided on the shaft main body, chuck means fixed to the front end of the core tank, and the chuck means. A wound chuck spring, a chuck ring loosely fitted to the chuck of chuck means, an inner cylinder provided via the core tank and the mouthpiece means, and a fitting cylinder attached to the rear part of the inner cylinder. A sleeve provided in the cap means, a return spring interposed between the sleeve and the inner cylinder, and a knock means provided at a rear end of the lead tank. Do-it-yourself mechanical pencil. 2. A shaft main body comprising a front shaft and a rear shaft, a core tank slidably provided on the shaft main body, chuck means fixed to the front end of the core tank, and the chuck means. A wound chuck spring, a chuck ring loosely fitted to the chuck of chuck means, an inner cylinder provided via the core tank and the mouthpiece means, and a fitting cylinder attached to the rear part of the inner cylinder. A sleeve provided in the base means, a return spring provided at a rear end of the inner cylinder,
A knock-type mechanical pencil, comprising: a knock means provided at the rear end of the lead tank. 3. The knock according to claim 1, wherein a slider integrally formed with a tip pipe slidably in the axial direction is inserted in the front portion of the front shaft. Type mechanical pencil. 4. The knocking type according to claim 1, wherein a tip having a small hole for inserting the tip pipe is screwed into a tip portion of the front shaft. Sharb pencil. 5. The knock type according to claim 1, wherein a rear end portion of the inner cylinder is connected to a fitting cylinder fitted to an inner circumference of the shaft body by a connecting cylinder. mechanical pencil. 6. The knock-type mechanical pencil according to claim 5, wherein the connecting cylinder and the fitting cylinder are formed with a recess inward in the radial direction. 7. An engagement groove is formed at a rear end of the fitting cylinder, and a projection that engages with the engagement groove is formed at an outer peripheral portion of the inner cylinder. The knock type mechanical pencil according to Item 1. 8. A plurality of split grooves for expanding the diameter are formed in the axial direction at the rear end of the fitting cylinder, and a locking portion is provided at the rear portion thereof, while the outer peripheral portion of the inner cylinder is provided. The protrusion that is locked with the locking portion is formed.
Knock type mechanical pencil described in. 9. An engagement hole is formed apart from the rear end of the fitting cylinder, and a protrusion is provided on the inner cylinder, and slits are formed on both sides of the protrusion. The knock type mechanical pencil according to claim 1. 10. The knock type mechanical pencil according to claim 1, wherein the fitting cylinder and the inner cylinder are screwed together at a rear portion.