JPS5842145Y2 - Mechanical pencil lead guide tube fixing device - Google Patents

Description

[Detailed description of the invention] This invention is placed at the tip of the mechanical pencil to guide the lead from inside the mechanical pencil to the outside, and to prevent the lead from bending as much as possible when writing, thereby preventing breakage of the lead. This invention relates to a lead-core guide tube.

Conventionally, mechanical pencils have a tube body (hereinafter referred to as a lead guide tube) that has an inner diameter that is approximately the same diameter as the outer diameter of the lead core or slightly larger than the outer diameter of the lead core, in order to guide the lead core and prevent it from breaking. ) is fixed to the tip of the mechanical pencil.

This conventional lead guide tube is fixed to the tip of the mechanical pencil, so if the mechanical pencil is accidentally dropped, the lead guide tube will bend and the lead will not be able to pass through, making it unusable. It was possible.

The present invention has been devised to overcome the above-mentioned conventional disadvantages, and will be described in more detail below with reference to embodiments shown in the accompanying drawings.

In the figure, reference numeral 1 denotes a mechanical pencil main body, and a hole 2 is provided at the front end of the main body 1 to communicate the inside of the main body 1 with the outside. A front hole 3 having a larger diameter than the inner diameter of the hole 2 is provided.

The front hole 3 includes a large diameter portion 4 having an outer diameter approximately equal to or slightly larger than the inner diameter of the front hole 3, and a large diameter portion 4 having an outer diameter smaller than the inner diameter of the front hole 3. An annular locking body 7 having a small diameter part 5 having a symmetrical outer diameter and having an inwardly directed protrusion 6 on the inner surface of the small diameter part 5 is press-fitted, bonded, or It is attached with screws, etc.

Reference numeral 8 is a lead lead guide tube that guides a lead lead (not shown) from inside the mechanical pencil body 1 to the outside.
is connected to a tube body 9 whose front portion normally projects outward from the main body 1 and has an inner diameter slightly larger than the outer diameter of the lead core, and a rear portion of the tube body 9; A recess 10 that can be engaged with and disengaged from the protrusion 6 is intersected by an engaging body 11 provided on the outer surface.

A holding member 12 that lightly holds the lead core is attached to the engaging body 11.

The holding body 11 may be formed integrally with the tubular body 9 or formed separately and fixed thereto.

Further, the circumferential engagement between the protrusion 6 and the recess 10 is sufficient as long as the engagement is performed with an engagement force that does not come off due to the pressure of normal writing.

Reference numeral 13 is a lead core feeding mechanism disposed within the main body 1 and behind the locking body 7, and the diameter is reduced by a tightening ring 14 whose movement distance in the front and back direction is regulated. , and a collet chuck 15 that is expanded.

Next, the effect will be explained.

In normal writing, as shown in the figure, the protrusion 6 and the four parts 10 are in an engaged state, and in this state, the lead is protruded an appropriate length from the front end of the tubular body 9 to perform writing.

As writing continues, the lead lead wears out, and the front end of the tubular body 9 comes into contact with the writing surface, so that writing pressure is applied directly to the tubular body 9.

Even if the writing pressure is applied directly to the tube body 9, the protrusion 6 and the recess 10 are engaged with an engagement force that is greater than the writing pressure, so the tube body 9, that is, the lead guide tube 8 is pressed against the main body 1. It never moves.

The engagement between the protrusion 6 and the recess 10 described above is such that when a large impact force is applied to the tube body 9, such as when the body 1 is accidentally dropped, the small diameter portion 5 of the locking body 7 and the body 1 Since a gap is formed between the front hole 3 and the small diameter portion 5, it is released by expanding outward.

When the engagement between the protrusion 6 and the recess 10 is released in this manner, there is nothing to restrict the movement of the lead core guide tube 8, and therefore the lead core guide tube 8 is moved into the main body 1.

To return to the writing state further, the rear end of the lead guide tube 8 located inside the main body 1 is pressed by the front end of the collet chuck 15 to move the lead guide tube 8 forward, and the protrusion 6 and the four parts 10 are The lead core guide tube 8 is fixed to the main body 1 by re-engaging the collet chuck 1.
Either the lead core is sent out by the forward and backward movement of 5, or the protrusion 6 and the recess 10 are engaged by strongly pulling the tube 9 forward, or the locking body 7 is detachably attached to the front part of the main body 1. In this case, after removing the locking body 7 from the main body 1, the lead core guide tube 8 can be set on the locking body 7, and the locking body 7 can be assembled into the main body 1, thereby making it ready for use. .

As explained above, the large diameter part is arranged in the front hole in the mechanical pencil body and has an outer diameter that is approximately the same as or slightly larger than the inner diameter of the front hole, and an annular locking body having a smaller diameter than the inner diameter of the mechanical pencil body and having an inward protrusion on the inner surface of the small diameter portion; It has a lead core guide tube provided with a recess through which the body can be engaged and detached,
According to the present invention, in which the protrusion and the recess are engaged with each other by an engagement force greater than the writing pressure, the lead guide tube 8 is integrated with the main body 1 during normal writing, and serves as a guide for the lead lead. At the same time as protection, if the main body 1 is accidentally dropped or a large amount of force or impact is applied to the lead core guide tube 8, the lead core guide tube 8 can be moved into the main body 1. Because of this, stable writing can be achieved without the lead guide tube 8 wobbling during writing, the bending of the lead guide tube 8 due to dropping etc. can be prevented, and the lead can always be fed out smoothly, which has practical effects. It is a big thing.

As shown in the figure, a stepped portion 16 is formed on the rear inner surface of the large diameter portion 4 of the locking body 7 to restrict the amount of movement of the lead core guide tube 8 when it is moved into the main body 1. It is okay to do something like this.

[Brief explanation of the drawing]

The figure is a sectional view showing the present invention. 1...Main body, 3...Front hole, 4...
...Large diameter part, 5...Small diameter part, 6...
Projection body, 7... Locking body, 8... Lead core guide tube, 10... Concave portion.

Claims (1)

[Scope of utility model registration request] a large diameter part disposed in the front hole in the mechanical pencil body and having an outer diameter approximately equal to or slightly larger than the inner diameter of the front hole; and a larger diameter part having a smaller diameter than the inner diameter of the front hole. an annular locking body that has a small diameter part and has an inward protrusion on the inner surface of the small diameter part; A lead mechanical pencil, comprising a lead guide tube provided with a recess that allows the body to engage and disengage, and wherein the protrusion and the recess are engaged by an engagement force greater than writing pressure. Core guide tube fixing device.