JPS6130879Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the structure of a knob cover that is engaged with the rear end of the barrel of a sharp pencil, ballpoint pen, etc., and prevents the knob cover from easily slipping out from the rear end of the barrel and causing powder to be lost. In addition, the notch cover can be easily inserted, and even if the lead case is thin, the fitting force between the lead case and the knock cover can be set appropriately, and the lead case will not deform when inserting the knock cover. The purpose of this invention is to obtain a knock cover structure that does not have an adverse effect on

The fitting force of the knob cover used in conventional sharp pencils, ballpoint pens, etc. to the main body is maintained by the frictional force with the lead case. However, because the diameter of the core case and the notch cover themselves are small and the rigidity of both parts is large, there is variation in the strength of the mating force, and it is difficult to obtain an appropriate mating force between the two. is extremely difficult. Therefore, it has the disadvantage that the cover is easily lost in a pocket or the like.

As described in the claims of the above-mentioned utility model registration, the present invention has several ridges protruding from the outer peripheral surface of the knob cover at appropriate intervals, and the diameter of the circumscribed circle of the ridges is as follows: The raised portion is formed on the rear end surface of the shaft cylinder and has a slightly larger diameter than the inner diameter of the insertion hole of the knob cover, which has a smaller diameter than the inner diameter of the shaft cylinder. The outer diameter of the knob cover excluding the hole is slightly smaller than the inner diameter of the insertion hole, and the inner diameter is larger than the outer diameter of the core case. Several ribs that contact the outer circumferential surface of the core case are formed at positions where the raised part and the knob cover are not formed, and the knob cover is fitted and inserted when the raised part and the knob cover are bent toward the core case due to their elastic force. This device is configured to have a shape that allows it to pass through the hole, and the present invention has the above-mentioned configuration, so that the knob cover can be attached and detached by simply pushing or pulling it, and after insertion, the knob cover is attached to the rear end of the shaft cylinder. Since it does not easily come off from the hole, there is no risk of the knot cover becoming powdery. Furthermore, even if the core case is thin, just by changing the diameter of the rib and molding, the fitting force between the core case and the knot cover can be set to an appropriate level. Therefore, it is possible to deal with variations in the fitting force between the two, and since the notch cover fits and passes through the shaft cylinder, there is no possibility of strong tensile force being applied to the core case, and there is no adverse effect on the core etc. It achieves exceptional effects such as no harmful effects.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated based on the Example shown in drawing.

1 to 3 show an embodiment of the present invention, in which a plurality of (two in the illustrated embodiment) protruding portions 2 are provided at appropriate intervals on the outer circumferential surface of the front part of the knob cover 1. has been done. The diameter a of the circumscribed circle of the raised portion 2 is slightly larger than the inner diameter b of a fitting hole portion 10 formed in the rear end surface of the shaft cylinder 3 and into which the knob cover 1 is inserted. Further, the diameter a of the raised portion 2 is slightly smaller than the inner diameter of the shaft cylinder 3. The outer diameter c of the outer peripheral edge of the knock cover 1 from which the raised portion 2 is not protruded is slightly smaller than the inner diameter b of the insertion hole portion 10. Further, the inner diameter of the knob cover 1 is larger than the outer diameter of the core case 5.

The insertion hole 10 of the shaft cylinder 3 is formed with a flange portion in which the rear end of the shaft cylinder 3 is bent inward.
The diameter is smaller than the inner diameter of the

As shown in the figure, the raised portion 2 has a tapered peripheral surface, that is, the raised portion 2 has a shape that allows the raised portion 2 to smoothly pass through the insertion hole 10.
Although the raised portion 2 is formed in a chevron shape in the illustrated embodiment, it may be formed in a semicircular arc shape.

As shown in FIGS. 2 and 3, a plurality (two in the illustrated embodiment) of the hollow inner circumferential surface of the knock cover 1 are located at positions where the raised portions 2 are not formed, that is, positions shifted from the raised portions 2. A rib 4 is provided to protrude inward, and the diameter of the inscribed circle of the rib 4 is approximately equal to the outer diameter d of the core case 5 to which the knob cover 1 is attached.

As shown in FIG. 3, the raised portion 2 and the knob cover 1 have elasticity so that they can be bent toward the center, that is, toward the core case 5, by pressure from the outside.

With the above-described structure, when the knob cover 1 is fitted between the shaft tube 3 and the core case 5 while being attached to the core case 5, the raised portion 2 protruding from the knob cover 1 will fit into the insertion hole 10 of the shaft tube 3. As shown in FIG. 3, the protrusion 2 and the knob cover 1 are bent in the direction of the core case 5 due to their elasticity, so that the protrusion 2 passes through the insertion hole 10. and the knob cover 1 is attached. The raised portion 2
After the knock cover 1 passes through the insertion hole 10, its elastic force returns it to its original state as shown in FIG.

Furthermore, the ribs 4 provided on the inner circumferential surface of the knob cover 1 are in light contact with the outer circumferential surface of the core case, thereby preventing the knob cover 1 from shaking loosely after being fitted into the shaft cylinder 3. At the same time, the knock cover 1 is movable in the longitudinal direction of the shaft cylinder 3.

When the knob cover 1 is removed from the barrel 3, the knob cover 1 and the raised portion 2 function in the same manner as when they are inserted and inserted.

According to the present invention, by providing a raised portion on the outer circumferential surface of the knob cover, the knob cover can be easily attached and detached from the shaft cylinder with only a temporary fitting force, and after fitting, the knob cover can be easily attached and detached from the shaft cylinder as before. The knob cover does not easily fall off from the shaft cylinder. Furthermore, even if the core case is thin, the fitting force between the core case and the knob cover can be set appropriately by simply changing the diameter of the rib and molding it. Furthermore, the knob cover can be made of elastic resin or the like, and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1: Knock cover, 2: Protrusion, 3: Shaft cylinder,
4: Ribs.

Claims (1)

[Scope of utility model registration request] Several ridges are protruded at appropriate intervals on the outer peripheral surface of the elastic knob cover, and the diameter of the circumscribed circle of the ridges is smaller than the inner diameter of the shaft cylinder. The knob cover is formed on the rear end surface of the barrel and has a diameter slightly larger than the inner diameter of the insertion hole of the knob cover, which is smaller in diameter than the inner diameter of the barrel. The inner diameter of the hole is slightly smaller than the inner diameter of the hole, and the inner diameter is larger than the outer diameter of the core case. several ribs are formed in contact with the outer circumferential surface of the ridge, and when the raised portion is located in the insertion hole, the knob cover is bent toward the core case side by the insertion hole, A knock cover structure for a writing instrument, characterized in that it is formed in a chevron shape or a semicircular arc shape with a tapered part so as to be able to pass through the insertion hole.