JPH0335586Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tip-knock type sharp pencil whose lead core is drawn out by notching the tip.

As a sharpening pencil with a tip,
Various structures are known, but most of them are complicated and economically difficult to obtain.

In order to eliminate such drawbacks, the present invention provides a tip pipe and a chuck that are movable in the axial direction on the barrel, and when the tip pipe returns to the lower end of the barrel after knocking the tip, the chuck clamps the lead core. The pipe moves forward in this state, and the lead core protrudes from the lower end of the tip pipe.

This will be explained below with reference to the drawings.

In what is shown in the figure, a connector 2 is screwed to the lower end of the shaft tube 1, and a tip pipe 3 is inserted through the connector so as to be movable in the axial direction. The tip pipe 3 has a flange 5 on the upper side so as to come into contact with the inner shoulder 4 of the connector 2, and a cylindrical portion 7 such that the lower part of the flange is guided into the insertion hole 6 of the connector 2. The lower part of the cylindrical part is a tapered part 8, and a core protection tube part 9 is formed at the tip. An intermediate piece 12 having an insertion hole 11 for a lead core 10 is fixed to the upper part of the connector 2, and an inner cylinder 13 is provided protruding below the intermediate piece. The chuck 14 that holds the lead core is formed in two halves so that the upper part can expand elastically, and when expanded, the peripheral edge 15 elastically slides against the inner wall 16 of the inner cylinder, and the chuck axially Provides a braking effect when moving to. The chuck ring 17, which serves to fasten the chuck, has a flange 18 at its rear portion, which abuts against the lower end of the inner cylinder. It is preferable that the angle of inclination of the engagement portion between the chuck and the chuck ring is relatively acute.For example, in the case of the ordinary knot-type sharp pencil currently in use, the angle of inclination is approximately 3 degrees, so it is sharper than this and approximately 2 degrees. If the angle is set at around 100°, the chuck will have to travel a long distance to fully engage the chuck ring while holding the lead core.
As will be described later, it is easy to ensure the amount of protrusion of the lead core that protrudes from the lower end of the tip pipe. In addition, the fit between the chuck and the chuck ring should be such that it does not come off with a normal writing pressure of about 400 g. In the case shown in the figure, the chuck should come off from the chuck ring when about 600 g of writing pressure is applied. It has been set. Below the chuck above is a spring catch 1.
A spring 20 is provided between the spring seat and the flange 18 of the chuck ring 17 to urge the chuck 14 downward in the axial direction. The lower end 21 of the chuck 14 faces the inner stepped portion 22 of the tip pipe 3, and is in contact with the stepped portion under the action of the spring 20 in use. A spring 23 is provided between the upper part of the tip pipe 3 and the intermediate piece 12 so as to bias the tip pipe axially downward, and preferably the spring 23 biases the chuck.
It has a biasing action stronger than the biasing action of 0, and when the chuck and the tip pipe knock the tip and return to the original protruding position, the tip pipe surely returns to the protruding position before the chuck. There is.

As shown in FIG. 1, the tip pipe 3 and the chuck 14 are biased by the springs 20 and 23, and writing is continued with the end pipe 3 and the chuck 14 positioned toward the lower end of the barrel 1, and the lead 10 decreases. Then, with the core protection tube part 9 of the tip pipe 3 in contact with the paper surface 24, push the shaft tube 1 downward. This state is shown in FIG. 2, where the chuck ring 17 that was fastening the chuck 14 is lowered relatively downward, so the upper part of the chuck 14 expands and the lead core 10 becomes free. The upper peripheral edge 15 comes into elastic sliding contact with the inner wall 16 of the inner cylinder. In addition, to first supply the lead core 10 to the tip pipe 3, if the lead core 10 is dropped into the insertion hole 11 of the intermediate piece 12 in the state shown in FIG. reach up to.

Next, when the shaft tube 1 is raised, the lead core is in a free state, so it remains in the same positional relationship as the tip pipe 3 due to its own weight (FIG. 3). On the other hand, the chuck 14 has its lower end 21 in the state shown in FIG.
is in a state where it hits the inner step 22 of the tip pipe 3, its upper end is open, and its peripheral edge is in elastic sliding contact with the inner wall 16 of the inner cylinder, but the tip pipe 3 and the shaft cylinder 1 are
By relatively moving up and down as shown in FIG. 3, the chuck ring 17 gradually tightens around the outer periphery of the chuck 14 and comes to grip the lead core. At this time, as shown in the figure, the spring 20 that biases the chuck 14 is made weaker than the spring 23 that biases the tip pipe 3, and the upper peripheral edge 15 of the chuck 14 is slid against the inner wall 16 of the inner cylinder 13. Since the chucks are brought into contact to exert a braking effect, the movement of the chuck lags behind the movement of the chuck ring 17, so that the state shown in FIG. 3 is reliably achieved. Then, the tip pipe 3 and the barrel 1 move until the flange 5 of the tip pipe 3 comes into contact with the inner shoulder 4 of the connector 2, and during this time, the chuck 14 exerts a clamping action by the chuck ring 17. In the starting state, a moving space 25 is formed between the lower end 21 of the chuck and the inner step 22 of the tip pipe 3.

Here, the core protection tube part 9 of the tip pipe 3 is
4, the lower end of the lead core 10 becomes free, so the chuck 14 holding the lead core moves forward in the moving space 25 while holding the lead core under the action of the spring 20. The lead core 10 is the tip pipe 3
It protrudes downward from the core protection tube part 9.

The engagement between the chuck 14 and the chuck ring 17 is secured so that it does not come off under normal writing pressure (approximately 400 g), so even if you write in the state shown in Figure 4, the lead will not pull in. Never.

When the amount of lead core is reduced, the tip pipe can be knocked and the lead core can be fed out by the operation described above.

The present invention is constructed as described above, has a simple structure, can be manufactured economically, and can reliably feed out the lead core by notching the tip.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Fig. 1 shows the lead core reduced, Fig. 2 shows the tip with the tip notched, Fig. 3 shows the tip with the tip stopped, and Fig. 4 shows the tip with the tip removed. FIG. 3 is a cross-sectional view taken away from the paper surface. 1...Shaft tube, 3...Tip pipe, 12...Intermediate piece, 13...Inner cylinder, 14...Chick, 17...
Chuck ring, 20, 22...spring.

Claims (1)

[Scope of utility model registration request] A tip pipe is provided at the lower end of the axial cylinder so as to be movable in the axial direction, an intermediate piece having a lead core insertion hole is formed inside the axial cylinder, an inner cylinder is protruded below the intermediate piece, and an inner cylinder is provided inside the inner cylinder. A chuck for holding the lead core is provided to be movable in the axial direction, and a chuck ring for tightening the chuck is brought into contact with the lower end of the inner cylinder, and when the chuck is removed from the chuck ring, the rear end expands and the chuck for tightening the chuck is attached to the inner cylinder. The chuck is provided so as to be expandable so as to come into elastic sliding contact with the inner wall of the cylinder, the lower end of the chuck is opposed to the inner step of the tip pipe, the tip pipe and the chuck are each urged downward in the axial direction, and the chuck is A tip-knot type sharp pencil in which the spring that biases the tip pipe has a stronger biasing action than the spring that biases the tip pipe.