JPH07304294A - Component mounting device for writing instrument - Google Patents

Abstract

PURPOSE:To integrally form a stator with a shaft joint without necessity of processing with a labor hour, without damaging an 0-ring with a screw, and further without dropping an inner mechanism from a barrel even if a tip unit is removed after the mechanism including the joint is assembled with the barrel, and to further integrally form the stator with the joint with a simple structure. CONSTITUTION:A component mounting device for a writing instrument has a shaft joint 6 having a threaded part at its end, and inserted from the rear end of a barrel 1 and fixed to the barrel 1 so that the threaded part of the inner periphery of the barrel 1 is engaged with that of the joint 6, and comprises an 0-ring 7 interposed in a compressed state between the joint 6 and the inner periphery of the barrel 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting device for a writing instrument such as a sharp pencil, and more particularly to a mounting device for a shaft coupling and a tip tool which are components of the writing instrument.

[0002]

2. Description of the Related Art Hitherto, as a component mounting device for a writing instrument of this type, a structure for preventing loosening of a mouthpiece due to vibration in a mechanical pencil has been proposed, which is disclosed in Japanese Utility Model Publication No. 55-5347. FIG. 3 shows such a conventional device, in which a base portion 12b of a shaft coupling 12 having a threaded portion 12a is inserted from the front end side of the shaft cylinder 11 to be fixed to the shaft cylinder 11 so as to fix the shaft joint 12. Base 1 on the screw part 12a
In the mechanical pencil in which the threaded portion 13a on the inner periphery of 3 is screwed, an O-ring 14 is interposed between the shaft coupling 12 and the base 13 in a compressed state. That is,
The base 12b is inserted rearward from the hole 15 at the tip of the barrel 11, and the step 12c inside the base 12b is the barrel 1.
1 is in contact with the outer surface of the tip. And this base 12
A stator 16 is press-fitted into b to fix the shaft coupling 2 to the shaft cylinder 11.

[0003]

In the conventional device having such a structure, the O-ring 14 is provided on the base 13 side,
Moreover, it was close to the screw portion 12a. Therefore, the shaft coupling 12
The O-ring 14 may be damaged when the cap 13 is screwed onto the base, and the O-ring 14 may be torn in an extreme case.

Further, in such a conventional structure, the stator 16 is required in addition to the shaft joint 12, and the shaft joint 12 is fixed to the shaft cylinder 11 by press fitting the stator 16, and Since the screw 13 is screwed to the shaft coupling 12, the rotation stopper is not sufficient, and as a result, the mouthpiece 13 idles and screwing may be difficult. Therefore, in order to prevent the shaft joint 12 from rotating, the shaft cylinder 11 and the shaft joint 12 must be engaged with each other by a key groove, a polygon, or a screw.
And, these engaging structures need not be processed by processing a portion having a small diameter. Generally, as shown in FIG.
The outer surface of 7 has a polygonal shape, and the inner surface of the shaft cylinder 11 has a polygonal shape to prevent the rotation. If you do not do this, when you set the base 13 to the shaft coupling 12, the shaft coupling 1
2 rotated, and the base 13 and the shaft coupling 12 could not be screwed.

Therefore, according to the present invention, the outer surface of the stator 17 does not need to be processed into a polygonal shape as described above, and the O-ring 14 is provided inside the barrel 11.
It is an object of the present invention to provide a device which does not damage the O-ring 14 with 2a. Furthermore, the present invention provides a device in which the internal mechanism does not drop off from the shaft cylinder 11 even after removing the mouthpiece 13 as a tip tool after once assembling the internal mechanism including the shaft coupling 12 into the shaft cylinder 11. The purpose is to Still another object of the present invention is to provide a device having a simple structure because the stator 16 can be formed integrally with the shaft coupling 12.

[0006]

In order to achieve the above object, according to the present invention, a shaft coupling having a threaded portion at its tip is inserted from the rear end of the shaft cylinder and fixed to the shaft cylinder. A writing instrument in which a threaded portion on the inner circumference of a tip tool is screwed onto the threaded portion of the writing instrument, and a component mounting device for a writing tool, wherein an O-ring is interposed in a compressed state between the shaft coupling and the inner circumference of the shaft cylinder. Is obtained.

[0007]

In the writing instrument, the shaft joint having the threaded portion at the tip is inserted from the rear end of the shaft cylinder and fixed to the shaft cylinder, and the threaded portion of the inner circumference of the base is screwed to the threaded part of the shaft joint. Since the O-ring is interposed between the shaft joint and the inner circumference of the shaft cylinder in a compressed state, the internal mechanism including the shaft joint and the tip can be easily and surely attached to the shaft cylinder.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a cross-sectional view in which the device of the present invention is applied to a mechanical pencil, in which a barrel 1 is formed to have a slightly narrower width in the distal direction, that is, a smaller diameter. A flange portion 1a directed radially inward is formed at the tip portion thereof, and a step portion 1b is formed axially inward.

Inside the shaft cylinder 1, a wick tank 2 accommodating a wick and a chuck 4 in which a chuck ring 3 is loosely fitted at a front end thereof are provided.
It is mounted integrally with and slidably in the axial direction. The shaft coupling 1 is fixed to the shaft cylinder 1 via the chuck spring 5 and these. More specifically, the shaft coupling 6 has a male threaded portion 6a on the outer periphery of the front portion and an annular groove 6b for accommodating a rubber O-ring 7 on the outer periphery of the rear portion. Incidentally. Naturally, this annular groove 6b
Is formed to be slightly shallower than the diameter of the O-ring 7, and is configured to be compressed by the inner peripheral wall of the barrel 1 when inserted into the barrel 1. As a result, O-ring 7
The shaft joint 6 is strongly press-fitted and fixed to the shaft cylinder 1 by the elastic action of.

Further, the male screw portion 6a formed on the outer periphery of the front end of the shaft coupling 6 is projected from the front end opening of the shaft cylinder 1, and the male screw portion 6a has a female screw portion 8a formed on the inner circumference of the front portion. The tip 8 is screwed on. Note that reference numeral 9
Is a rubber packing with a large friction coefficient for holding the core.

Next, the operation of the apparatus according to this embodiment will be described. The core tank 2, the chuck ring 3, the chuck 4, and the chuck spring 5 are incorporated into the shaft joint 6 in advance, and the O-ring 7 is fitted in the annular groove 6b formed on the outer periphery of the rear portion of the shaft joint 6. The internal mechanism including the shaft coupling 6 assembled in this way is inserted from the rear end of the barrel 1.

At a position where the male screw portion 6a formed at the front portion of the shaft coupling 6 projects from this opening, the O-ring of the shaft coupling 6 is just pressed against the inner circumference of the shaft cylinder 1, so that the shaft coupling 6
The internal mechanism including is firmly fixed to the barrel 1. In this state, the mechanical pencil can be assembled by screwing the female screw portion 8a of the tip 8 having the packing 9 inside into the male screw portion 6a of the shaft coupling 6. It should be noted that this mechanical pencil can be drawn with its core extended by a normal operation.

FIG. 2 shows another embodiment of the present invention. The difference from the above embodiment is that the shaft joint 6 does not have an annular groove 6b, and instead, an O-ring 7 is provided on the outer peripheral step 6c of the shaft joint 6. Is installed. In this case as well, similar effects can be obtained by the same assembly as in the above-described embodiment, and the O-ring 7 is also compressed in the axial direction by strongly screwing the female screw portion 8a of the tip tool to the male screw portion 6a of the shaft coupling 6. Therefore, it is possible to prevent loosening of the tip tool.

[0014]

Since the device of the present invention is constructed as described above, it does not require time-consuming machining, and the O-ring is not damaged by the screw, and the internal mechanism once including the shaft coupling is provided. There is an effect that the internal mechanism does not drop off from the shaft cylinder even if the mouthpiece which is the tip tool is removed after the is assembled into the shaft cylinder. Furthermore, according to the present invention, since the stator can be formed integrally with the shaft coupling, it is possible to obtain a device having an extremely simple structure.

[Brief description of drawings]

1 is a cross-sectional view of an embodiment of the device according to the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the device according to the present invention.

FIG. 3 is a cross-sectional view of a device for preventing loosening of a mouthpiece in a conventional mechanical pencil.

FIG. 4 is a perspective view of an internal mechanism showing a conventional polygonal shaft coupling for detent.

[Explanation of symbols]

 1 Shaft cylinder 2 Core tank 3 Chuck ring 4 Chuck 5 Chuck spring 6 Shaft joint 7 O-ring 8 Tip tool 9 Packing

Claims (4)

[Claims] 1. A shaft coupling having a threaded portion at its tip is inserted from the rear end of the barrel to be fixed to the barrel, and a threaded portion on the inner circumference of the tip is screwed to the threaded portion of the shaft coupling. The writing instrument according to claim 1, wherein an O-ring is interposed between the shaft coupling and the inner circumference of the shaft cylinder in a compressed state. 2. The component mounting device for a writing instrument according to claim 1, wherein the tip end portion of the shaft cylinder has an inward flange portion, and the shaft joint is positioned by a step portion of the flange portion. 3. The component mounting device for a writing instrument according to claim 1, wherein an annular groove for accommodating an O-ring is formed on the outer periphery of the rear portion of the shaft coupling, and the O-ring is positioned in the annular groove. 4. A rear portion of the shaft coupling has a thick portion, and an O-ring is attached to an outer peripheral step portion of the thick portion.
Alternatively, the component mounting device for the writing instrument according to the item 2.