JPH0532313Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> This invention relates to a device that prevents accidental centering of a sharp-tip pencil while carrying it.

<Prior art> Conventional centering prevention devices for sharp pencils with a tip end include a type that locks a slider protruding from the tip of the barrel so that it cannot move (for example, see Japanese Utility Model Publication No. 61-32793), and a type that locks a slider protruding from the tip of the barrel so that it cannot move. There is a type (for example, see Japanese Utility Model Publication No. 61-32796) in which the opening is open so that the core is not clamped by the chuck. By the way, to briefly explain the latter, by pushing the tail plug protruding from the rear end of the shaft cylinder, the chuck body that makes up the ball chuck is advanced beyond the chuck outer cylinder, opening the chuck mouth, and locking it in this state. In order to do this, the tail plug is rotated, and the protrusion provided on the outer surface of the core storage tube, which rotates together with the tail plug, is engaged with the step formed on the inner surface of the shaft cylinder, and the mouth of the chuck is left open. The idea is to make this happen.

<Problems to be solved by the invention> The above-mentioned tail plug push-off rotation type centering prevention device has a relatively simple structure, which can be said to be an advantage, but it has the disadvantage that the tail plug protrudes long. . Also,
Considering when carrying it, when performing operations to prevent centering, at the same time, pull the slider protruding from the tip of the barrel and the core tube at the tip of the slider into the tip to reduce their protruding length. Although it would be desirable to shorten the length, the structure of the above-mentioned device does not allow this.

Therefore, in this invention, although the operating member is actuated to lock the chuck mouth in the open state, it is the same as the conventional example described above, but the operating member is an operating barrel whose protrusion length is not a problem at all. The object of the present invention is to provide a centering prevention device that simultaneously moves the slider backward when the chuck opening is locked in an open state by the backward movement and rotation of the operation cylinder.

<Means for solving the problem> This invention has a retreating edge of a slider with a core detent member that is biased rearward within a tip attached to the tip of the shaft cylinder and is movable in the axial direction. A tilting member disposed swingably in the nozzle is brought into contact with the front end face far from the swing fulcrum, and a knock spring is used to contact the front end face of the tilting member near the swing fulcrum with a knock spring. The front end surface of the stopper at the tip of the chuck outer cylinder, which receives the biasing force and the rotational force in one direction, is brought into contact with the
Guide grooves for the outer protrusion of the chuck outer cylinder and the inner protrusion of the operating cylinder rotatably engaged with the shaft cylinder are formed on the inner surface of the shaft cylinder, and the guide groove on the side to be pressed by the rotational force of the knob spring is formed on the inner surface of the shaft cylinder. By forming step portions facing each other that can collide at the position of the chuck outer cylinder when the lead is fed out, on the surface and the outer protrusion surface of the chuck outer cylinder, respectively.
Depending on the lever ratio of the tilting member, the slider is made into a type of tip-knob type sharp pencil in which the slider is retracted by a distance greater than the retraction length of the ball chuck. The chuck outer cylinder has an outer protrusion and an inner protrusion of the operating cylinder, which move backward in cooperation with each other when the operating cylinder moves back against the urging force of the knob spring. By moving the inner inclined surface formed at the rear end of the part and the outer inclined surface formed at the tip of the outer protrusion into contact with each other, the chuck outer cylinder is rotated along each other's radial inclined surface. While moving backward, the chuck is opened, and the front end surface of the inward protrusion of the operating cylinder can be locked to the locking step of the guide groove surface at the position of the chuck outer cylinder when the chuck is opened, thus opening the chuck. It gets locked in the wrong state.

<Example> In the example shown in Fig. 1-A, a ring 3 is fixed to the inner surface of the tip 2 attached to the tip of the shaft cylinder 1, and an annular tilting moving member is attached to the front part of the ring 3. is swingably provided so that it can assume an inclined position and an upright position in contact with the ring 3, and an internal spring 5 is attached to the front end surface of the tilting member 4 away from the swing fulcrum. The rear end edge of the slider 7 with the core tube 6 is in contact with the slider 7, which is biased rearward and is slidable in the axial direction. A known core detent member 8 is provided inside the slider 7.
is installed.

The front end surface of a stopper 15 at the tip of the chuck outer cylinder 11 receives a forward biasing force and a unidirectional rotational force by a knock spring 9, and comes into contact with the rear end surface of the tilting member 4 near the pivot point. This chuck outer cylinder 11 is assembled with a ball 12, a chuck body 13, and a chuck spring 14 to constitute a known ball chuck 10. On the outer peripheral surface of the chuck outer cylinder 11, there is an outer surface that is continuous with the front end surface 11d. An outward protrusion 11a having a slanted surface 11c and a stepped portion 11b protrudes from the outer protrusion 11a.

A guide groove 16 is formed on the inner surface of the shaft cylinder 1, and has a groove surface 16a provided with a stepped portion 16b and a locking step portion 16d, and an opposing groove surface 16c. The side protrusion 11a is connected to both steps 11
Insert so that b and 16b face each other. Also inserted into the guide groove 16 is the inner protrusion 17a of the operating barrel 17 that is rotatably and retractably engaged with the shaft barrel 1. The inner protrusion 17a is formed with an inclined surface 17c that cooperates with the inclined surface 11c of the chuck outer cylinder 11, a continuous surface 17b, and a front end surface 17d (FIG. 1-B).

Chick outer tube 1 when not writing
1, by the rotational force of the knock spring 9, the side surface of the outer protrusion 11a on which the step portion 11b is formed is turned into the groove surface 16a on the side where the step portion 16b of the guide groove 16 is formed.
The outward inclined surface 11 is pushed forward by the forward biasing force of the knock spring 9.
c, the inwardly inclined surfaces 17c overlap each other, and a gap A of approximately 0.3 to 0.4 mm is formed between the stepped portions 11b and 16b (Fig. 1-B). This gap A only becomes slightly narrower under normal writing pressure because the forward force of the knob spring 9 is strong. However, when the tip of the core 20 is pressed against the surface of paper, etc., the gap A becomes zero, and both stepped portions 11b, 16
A collision b occurs (Figure 2-B). The amount of retraction of the slider 7 at this time depends on the lever ratio of the tilting member 4, which is in an almost upright state.
Since the amount of retraction is greater than the amount of retraction, the core detent member 8 slides on the surface of the core 20 and holds the core 20 further back (Fig. 2-A). Therefore, when the tip of the core 20 that was being pressed is released from the surface of the paper to return to the state shown in FIG. 1-A, the core 20 held by the core detent member 6 moves forward without slipping, and the ball chuck 10 allows this, so that the desired lead delivery by the tip notch can be achieved.

Next, when carrying this sharp pencil, the operating barrel 17 is moved backward against the urging force of the knock spring 9, thereby causing the inner inclined surface 17c of the inner protrusion 17a of the operating barrel 17 to The outer inclined surface 11c of the outer protrusion 11a of the chuck outer cylinder 11 cooperates with the outer inclined surface 11c to move it to the opposing groove surface of the guide groove 16 (third-
B), the groove surface 16a is moved to a position that has nothing to do with the stepped portion 16b, and the operating cylinder 17 and the chuck outer cylinder 11 are moved back together as one (Fig. 3-C).
Thereafter, the operating barrel 17 is rotated slightly, and finally the front end surface 17d of the inner protrusion 17a of the operating barrel 17 engages and locks with the locking step 16d provided in the groove surface 16a, resulting in a locked state ( Figure 3-D).

In the process of the outward protrusion 11a of the chuck outer cylinder 11 retracting from the state shown in Fig. 3-B to Fig. 3-D, the ball chuck mechanism 1 with the core 20 initially
After the entire chuck body 13 retreats against the elastic force of the chuck spring 9 and the rear end surface of the chuck body 13 collides with the front end surface of the regulating tube 18, only the chuck outer cylinder 11 resists the elastic force of the chuck spring 14. retreat against. Therefore, in the locked state of FIG. 3-D, the chuck is left open.

On the other hand, when the entire ball chuck mechanism 10 retreats,
The slider 7 is pushed into the tip 2 by the repulsive force of the internal spring 5, and stops when the tilting member 4 pushed by the slider 7 collides with the ring 3 and becomes almost upright. Figure 3-A shows this state. It is clear from the figure that the protruding length of the core tube 6 is shortened.

In addition, in order to make the locking between the front end surface 17d of the operating barrel 17 and the locking step 16d of the guide groove 16 surface more reliable, as shown in FIG. A recessed portion 22 may be provided in the stepped portion 16d (the unevenness may be reversed).

<Effects of the invention> As is clear from the above explanation, the provision of the operating barrel 17 makes the shaft barrel 1 part a little thicker, but this has never been a hindrance, and the operating barrel 17 cannot be moved backwards. The chuck can be locked in the open state with the simple operation of turning the chuck, and when this is locked, the slider 7 is retracted into the tip 2 by a larger retraction amount than the ball chuck mechanism 10 due to the lever ratio of the tilting member 4. , the length of the protrusion of the core tube 6 attached to the tip of the slider 7 is reduced accordingly, which is extremely convenient when inserting it into a pocket or the like.

[Brief explanation of the drawing]

Figure 1-A is a cross-sectional view of the tip-knob type sharp pencil equipped with the centering prevention device of this invention when not writing, and Figure 1-B is the operating barrel and outside of the chuck in the state shown in Figure 1-A. A plan view showing the mutual relationship between the cylinder and the guide groove, Fig. 2-A is a sectional view when the tip is punched and pushed through, and Fig. 2-B is a plane corresponding to Fig. 1-B at that time. Figure 3-A
The figure is a sectional view when the chuck is locked in the open state, Figures 3-B to 3-D are plan views corresponding to Figure 1-B up to the lock, and Figure 4 is the operating barrel. FIG. 7 is a plan view showing another way of locking the chuck outer cylinder. 1... shaft cylinder, 2... lead metal, 4... tilting movement member,
7...Slider, 8...Core detent member, 9...
...Chuck spring, 11...Chuck outer cylinder, 1
1a...Outward protrusion, 11b...Stepped portion, 11c...
Outer inclined surface, 11d... Front end surface, 15... Stopper, 16... Guide groove, 16b... Step portion, 17...
...operation tube, 17a...inward protrusion, 17b...surface,
17c...inward inclined surface, 17d...engaging step portion.

Claims (1)

[Scope of utility model registration request] The rear end edge of the slider 7 with a core detent member 8 which is biased rearward within the tip 2 attached to the tip of the shaft cylinder 1 and is movable in the axial direction can be swung into the tip 2. A knock spring 9 is brought into contact with the front end face of the tilting member 4 located far from the swing fulcrum, and a knock spring 9 is brought into contact with the rear end face of the tilting member 4 near the swing fulcrum.
By this, the front end surface of the stopper 15 at the tip of the chuck outer cylinder 11, which receives the forward urging force and the rotational force in one direction, is brought into contact with the outer protrusion 11 of the chuck outer cylinder 11.
a and the guide groove 16 of the inner protrusion 17a of the operating cylinder 17 rotatably engaged with the shaft cylinder 1 are formed on the inner surface of the shaft cylinder 1, so that the guide groove 16 on the side to be pressed by the rotational force of the knob spring 9 is formed. 16 sides and chuck outer cylinder 11
Step portions 16 facing each other that can collide at the position of the chuck outer cylinder 11 when the lead is fed out are provided on the surface of the outer protrusion 11a.
b and 11b, respectively, and the outer protrusion 11a of the chuck outer cylinder 11 can be moved to the opposing groove surface of the guide groove 16 surface by retreating the operation cylinder 17 against the urging force of the knock spring 9, and the outer protrusion 11a of the chuck outer cylinder 11 can be moved to the opposing groove surface of the guide groove 16 surface. The inner inclined surface 17c formed at the rear end of the cooperating inner protrusion 17a and the outer inclined surface 11c formed at the tip of the outer protrusion 11a are slidably abutted, and the inner By moving the inclined surface 17c and the outer inclined surface 11c into contact with each other, the chuck outer cylinder 11 is rotated and moved rearward to open the chuck. The front end surface 17d of the inner protrusion 17a is inserted into the guide groove 16.
A centering prevention device for a sharpener pencil with a tip that can be locked to a locking step 16d on a surface.