JPS5913099Y2 - Knotsuku style pencil - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a knock-type mechanical pencil that has a simple structure and can be manufactured economically.

Conventionally, the chuck ring that controls the tightening of the chuck of knock-type mechanical pencils is made by cutting or plastic molding, but plastic molding deforms when gripping the pencil lead and can withstand the pressure of the writing. In addition, if the inner surface of a machined product is not polished or otherwise polished, it may not move smoothly and may cause a malfunction.

The present invention improves these drawbacks by manufacturing the chuck ring by press processing, eliminating the need for finishing the inner surface.
This invention relates to a knock-type mechanical pencil that is durable, easy to obtain, and economical.

In the embodiment shown in the figure, the base material 1 is a plate-shaped metal material made of brass with a thickness of about 0.4 mm, a hole 2 for positioning is provided in this material, and a die 3 and a punch 4 are used to punch the hole. A cylindrical part 5 having an inner diameter corresponding to the outer diameter of the fastening part of the chuck, whose upper periphery is cut at the same time as pushing in the periphery, or after that, and a flange part 6 extending outward at the tip of the cylindrical part; An inwardly expanding edge 7 is integrally formed at the base end of the cylindrical portion.

If the chuck ring is fitted into the chuck 9 connected to the lower part of the core tank 8 as is known, the inner surface of the cylindrical part is press-finished to be smooth without any unevenness, so it can be attached to the shaft cylinder 10. When it hits the stepped part 12 of the tip cap 11, the clamping part of the chuck is released without resistance, and when the wick tank returns to its original state due to the action of the spring 13, it smoothly and reliably engages with the chuck. It is possible to tighten the chuck and smoothly control opening and closing of the chuck.

Note that if an arcuate portion 14 is provided on the inner edge of the flange portion as shown in the figure, smoother operation can be achieved.

Since the present invention is constructed as described above, a plate-shaped base material 1 is press-worked, and a cylindrical part 5 having an inner diameter corresponding to the outer diameter of the fastening part of the chuck is formed, and an outer part is attached to the tip of the cylindrical part. A chuck ring is made in which a flange part 6 that spreads toward the side and an edge part 7 that spreads inward at the base end of the cylindrical part are integrally formed, and the chuck ring is fitted onto the outer periphery of the fastening part of the chuck. Therefore, the chuck ring can be obtained economically, and the cylindrical part of the chuck ring makes surface contact with the periphery of the fastening part (large diameter part) of the chuck, and slides in the state of surface contact when a knocking operation is performed. Because of this, there is little wear on the contact surface, and the chuck can be tightened uniformly along the outer surface of the large-diameter portion of the chuck to securely hold the core. The flange portion 6 provided at the tip that expands outward provides strength even when made from a thin plate-like substrate 1 as described above, and prevents the cylindrical portion from expanding and weakens the fastening effect of the chuck. Moreover, by providing the inwardly expanding edge 7 at the proximal end of the cylindrical portion, deformation of the cylindrical portion is further prevented, and the spring 13 is prevented from changing when no core is supplied to the chuck. Even if the chuck is pulled inward and deflated by the action, the edge 7 will catch on the small diameter part (neck) of the chuck that follows the large diameter part, and the chuck ring will not come out of the chuck and fall, thus preventing the core tank and the A knock-type mechanical pencil that can be used for a long time without fear of the chuck separating from the barrel 10 and breaking, is highly accurate, and is less likely to cause the lead to immerse or break down due to pen pressure, etc. can get.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with FIG. 1 being an enlarged sectional view, FIG. 2 being a perspective view of the base material, and FIG. 3 being an explanatory view showing the manufacturing process.

Claims (1)

[Scope of utility model registration request] A base material 1 is made of a plate-shaped metal material, which is pressed, and a cylindrical part 5 having an inner diameter corresponding to the outer diameter of the fastening part of the chuck is used to control the opening and closing of the chuck connected to the core tank. A knock-type mechanical pencil characterized by having a chuck ring integrally formed with a flange part 6 which spreads outward at the tip thereof and an edge part 7 which spreads inward at the base end of the cylindrical part.