JPS5925680B2 - Knotsuku style pencil and its assembly method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead holder that combines a chuck and a lead tank into one body, and a method for assembling a knock-type mechanical pencil using the lead holder, in order to obtain a knock-type mechanical pencil at a low price.

Conventional knock-type mechanical pencils consist of a three-part metal chuck and a plastic lead tank that are screwed together under the elastic force of a spring, and are caulked directly or indirectly with the metal lead tank through a fitting. As a result, the chuck was not only expensive but also inefficient to assemble, making it impossible to obtain a low-priced knock-type mechanical pencil.

Also, as an application similar to this invention, Japanese Patent Application Laid-Open No. 50-531
35, which is a plastic lead holder that combines a chuck part and a lead tank part, and is injection molded in half shells, resulting in a low-cost lead holder, but it requires a lot of work inside the shaft to assemble it. The assembly was troublesome because one half-shell had to be inserted into the other half-shell, and the other half-shell had to be shifted and inserted while being pressed against the elastic force of the spring using, for example, a semicircular pressing tool.

This invention involves injection molding a half-shell lead holder that integrates a chuck part and a lead tank part by connecting them with a hinge to obtain an inexpensive lead holder. The aim is to improve assembly efficiency by assembling each shell without shifting the lead holder, and to obtain a knock-type mechanical pencil at a low price.

Next, the configuration of this invention will be explained based on the drawings.
In the figure and FIG. 2, it has a conical convex portion 1A in the front part,
A lead holder 1 composed of a chuck part 1B that is curved outward and a lead tank part 1C having a larger diameter than the chuck part 1B.
By bending the core holder 1 about the hinge 1D at the rear end, which is composed of a pair of semicircular half shells, it is possible to easily form the core holder 1 in the shape of a rotary cylinder without shifting.

The pair of half-shell core holders 1 can also be injection molded by being bent in a dogleg shape around the hinge 1D, and the bending can be made easier.

In FIG. 3, a hinge 11D is provided at the side end of the core holder 11.

In general, the hinge of injection molded products has an extremely thin wall at the center of the bending toward the product side, and polypropylene is used as the material when bending is repeated, but in the case of a core holder, Since it is bent only once during assembly, there are no restrictions on the material, and any suitable material can be used to provide elasticity to the chuck part.

A method of assembling the lead holder constructed in this way into a knock-type mechanical pencil will be explained using an embodiment using a petal-shaped fastener.

In FIGS. 4, 5, and 6, the core consists of a chuck part 21B having a conical convex part 21A on the front part and an outer boxwood 21E with a vertical step on the rear part, and a large diameter wick tank part 21C. The holder 21 is injection molded in a pair of half-shells and bent around a hinge 21D to form a cylindrical shape, and the knob 2 is detachably attached to the rear part.

One end of the spring 3 is attached to the stepped portion 21F of the core holder 21 configured in this way and inserted from the rear of the shaft 4, and the other end of the spring 3 is brought into contact with the inner thigh 4B of the shaft 4. , further presses the core holder 21 to release the spring 30.
By pressing the knob 2 all at once against the elastic force, the chuck portion 21B of the lead holder 21 is made to protrude from the front end of the shaft 4.

In this state, a petal-shaped fastener 5 with a rear part having a small diameter 5C, elasticity divided into υ numbers, and an inner brim 5B with a vertical step on the inside front and a taper 5A on the rear part is installed. When pushed into the chuck part 21B of the lead holder 21 from the front, the fastener 5 and the chuck part 21B of the lead holder 21 are elastically deformed by the action of the taper 5A of the fastener 5, and the inner boxwood 5B of the fastener 5 is It is attached so as to hang over the outer collar 21E of the core holder 21.

After assembling in this way, when the pressure on the knob 2 is released, the outer step 5D of the fastener 5 is brought into contact with the front end surface 4C of the shaft 4,
Furthermore, the core holder 21 is elastically pulled backward by the elastic force of the spring 3, but once assembled, the inner flange 5B of the fastener 5 and the outer flange 21E of the core holder 21
Since the locking surfaces of the fasteners 5 and 5 are vertical, the elastic force of the spring 3 does not become a force that expands the inner flange 5B of the fastener 5, and the locking does not come off.

Note that if the diameter difference between the narrow diameter 5C of the fastener 5 and the inner diameter 4A of the shaft 4 is made very small, the fastener 5 will not be able to spread out, so that the locking will be more reliable.

Finally, the assembly is completed by screwing the base 7 containing the core holder 6 into the front part of the shaft 4 as shown in FIG. 5 so that the fastener 5 can be moved by a certain amount.

When the lead holder 21 does not hold the lead 8, the lead holder 2
10 The conical convex portion 21A is inserted into the inside of the fastener 5, and the outer brim 21E of the lead holder 21 and the inner brim 5B of the fastener 5 are engaged, but the lead holder 21 holds the lead 8. At this time, the conical convex portion 21A expands and locks onto the front end 5E of the fastener 5, and strongly holds the core 8 by a wedge action, so that the outer collar 2 of the core holder 21
1E and the inner brim 5B of the fastener 5 are separated by the distance that the lead holder 21 moves forward.

As explained above, this invention is made by injection molding a pair of half-shells each consisting of a chuck part and a lead tank part, connected by a hinge, so that it can be bent from the hinge without any deviation and is inexpensive. It is possible to obtain a cylindrical lead holder, which can be easily and efficiently assembled by simply pressing the fastener from the front, and a low-cost knock-type mechanical pencil can be obtained. It has various effects such as holding the core and preventing it from coming off even under extreme circumstances.

[BRIEF DESCRIPTION OF THE DRAWINGS] Figures 1 and 2 are perspective views showing a core holder in the present invention with a hinge provided at the rear end, and Figure 3 is a perspective view showing a lead holder in the present invention with a hinge provided at the side end. FIG. 4, FIG. 5, and FIG. 6 are longitudinal cross-sectional views showing a knock-type sharpening pencil using a petal-shaped fastener according to the present invention. 1, 11, 21... Core holder, 1A... Core holder 1
A conical convex portion in 1B...a chuck part in the lead holder 1, 1C...a lead tank part in the lead holder 1,
1D... Hinge in the core holder 1, 11D... Hinge in the core holder 11, 21A... Core holder 21
Conical convex portion in 21B...Chuck part in lead holder 21, 21C...Lead tank part in lead holder 21, 21D...Hinge in lead holder 21, 2
1E...Outer boxwood of core holder 21, 2...Knob, meter...Spring, 4...Shaft, 4A...Inner diameter of shaft 4, 4B...Inner thigh of shaft 4, 4C...・Front end surface of shaft 4, 5... Fastener, 5A... Taper in fastener 5, 5B... Inner rib of fastener 5, 5
C: Small diameter of the fastener 5, 5D: Outer step of the fastener 5, 5E: Front end of the fastener 5, 15F...
- Groove width in fastener 15, 6... Core holder, 7...
Old gold, 8 core.

Claims (1)

[Claims] 1. A chuck portion 21B provided with a conical convex portion 21A at the front and an outer boxwood 21E located at the rear of the conical convex portion 21A and whose rear side is a vertical step. and a large-diameter core tank portion 2 integrated with the chuck portion 21B.
The core holder 21 consisting of the core holder 1C is formed by injection molding into a pair of half shells and bent around the hinge 21D to form a cylindrical shape, and the knob 2 is detachably attached to the rear of the core holder 21. , core holder 210 stepped portion 21F and shaft 4
A spring 3 is stretched between the inner thigh 4B, and the rear part has a small diameter 5C and is divided into several parts to have elasticity.
A petal-shaped fastener 5 having an inner boxwood 5B with a vertical step on the inside front and a tapered rear part 5A is attached to the core holder 21.
The inner boxwood 5B is fitted over the outer boxwood 21E of the chuck portion 21B by being fitted outwardly from the front, and the fastener 5 is movable by a certain amount between the base 7 screwed onto the shaft 4 and the shaft 4. Knock-type mechanical pencil 0 2 A semicircular hinge 21 for each half shell having an outer brim 21E
A cylindrical core holder 21 is formed by bending a pair of core holders 21 connected at D around a hinge 21D.
The spring 3 is attached to the core holder 21, inserted from the rear of the shaft 4, and the core holder 21 is moved against the elastic force of the spring 3 between the shaft 4 and the core holder 21. Press and release shaft 4
The chuck portion 21B of the lead holder 21 is protruded from the front end of the
The rear part of the chuck part 21B is divided into several parts with a small diameter and has elasticity, and the front part is vertically stepped inside and the rear part is tapered 5A.
Push in the petal-shaped fastener 5 provided with the inner boxwood 5B from the front, and attach the inner boxwood 5B of the petal-shaped fastener 5 to the outer brim 21E provided on the core holder 21 by 9 degrees. A method for assembling a knock-type mechanical pencil, further comprising screwing together a base with a built-in lead holder 6 on the front part of the shaft 4.