JPH0224234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slider engagement/disengagement device for a tip-knob type mechanical pencil.

In the case of a tip-knot type sharp pencil, by pressing the tip of the slider's core tube or the tip of the core protruding from the core tube against the paper surface, the slider that holds the core with a detent and the chuck set that is biting the core can be moved back. the slider or the chuckset, for example by once locking the slider and then advancing the chuckset until the lock is released, or By once locking the chuck set, the desired centering can be performed by advancing the chuck set after the chuck set is released. Considering the above-mentioned slider locking and disengaging device, a locking member such as an O-ring is provided on the slider or shaft cylinder, and a locking groove of the locking member is formed on the shaft cylinder or slider. However, with this configuration, there was a tendency that it would not be possible to achieve the sharpness of instantaneous engagement and disengagement. In addition, if a configuration with a pawl body and a locking groove is adopted, after pressing hard again to release the lock, the pawl body must accelerate so as to jump over the locking groove, otherwise it will lock again. Therefore, it was necessary to quickly release the paper from the paper surface and to increase the spring pressure, and in this respect, the structure was not very suitable.

The purpose of the present invention is to eliminate the above-mentioned drawbacks by making use of the automatic locking phenomenon caused by friction and making it possible to securely lock the slider on the spot after eliminating the pressing of the core. An example will be explained as follows.

In the present invention, an automatic stop pipe 6 is provided between the shaft cylinder 1 and the slider 2, and the automatic stop pipe 6 is biased so as to be tiltable using the contact point with the inner surface of the shaft cylinder 1 as a fulcrum. A resilient member 5 such as a push spring or the like resiliently repels the slider 2 forward. The slider 2 is the same as described above in that it is provided with a core tube 3 protruding from a small hole at the tip of the barrel 1 and a core detent 4 exhibiting an appropriate core holding force. There are two ways to bias the automatic stop pipe 6 so as to tilt it. One of them is to be able to apply a force substantially parallel to the axial direction at a position away from the axial center. In this case, the coiled spring 10 shown in FIG. The seat portion 7 of the automatic stop pipe 6 is aligned and forms the force application point.
is provided on the opposite side to the support part 8 formed on the automatic stop tube 6, and the support part 8 comes into contact with the inner surface of the stop ring 11 fixed in the shaft cylinder 1, and serves as a fulcrum during tilting movement. The above-described coiled spring 10 may be a plate spring or other elastic body. An appropriate gap is provided by the inner surface of the shaft cylinder 1 and the stop ring 11 so as not to obstruct the tilting movement of the automatic stop pipe 6.

Another method of biasing is to apply a force almost perpendicular to the axial direction at a position away from the fulcrum.
In the example shown in FIG. 5, a spring portion 10'' is formed at the tip of a tube body 10' interposed between the shaft cylinder 1 and the automatic stop tube 6, and the inward pressing force of the spring portion 10'' The automatic stop pipe 6 is capable of tilting movement about a shoulder 8', which corresponds to the support 8 in FIG. 1, as a fulcrum.

Next, the locking force at the contact point between the straight outer surface of the slider 2 and the inclined inner surface of the automatic stop tube 6 will be explained using FIG. 4. P and R are the vertical pressing forces at the contact point, and this is tube 6
For example, it is determined by the strength of the coiled spring 10. Q is the horizontal pressing force exerted by the elastic member 5 on the slider 2, and μ is the coefficient of friction at the contact point.If Q>μP+μR, the automatic stop pipe 6 exerts a control action, but the slider 2 moves forward slowly. Become. On the other hand, if Q<μP+μR, the slider 2 can be locked in place. Therefore, in the present invention, if the frictional resistance at the contact point between the inner surface of the automatic stopper tube 6 and the outer surface of the slider 2 when the automatic stopper tube 6 is tilted is greater than the sum of the strength of the elastic member 5 and the core retaining force of the core detent 4. A pressing member 12 is disposed at the rear of the automatic stop tube 6 and is capable of elastically retracting and releasing from the rear end surface 9 of the automatic stop tube 6. Pressing member 1
In order to enable elasticity and release of the locking member 2 from the rear end surface 9 of the automatic stopper tube 6, the pressing member 12 and the chuck set 13, which clamps and releases the lead, may be connected in the following relationship.

The chuck set 13 includes the chuck body 14 and the wedge tube 1.
5, a chuck spring 16 is stretched between the shafts 1 and 5, and a rolling element 17 is interposed between the shafts. The wedge effect is further strengthened to strengthen the core clamping force, but against a force that pulls out the wedged core from inside the barrel 1, the wedge effect is generated because the chuck body 14 tries to move forward along with the core. becomes weaker and the chuck's mouth opens slightly to allow the lead to be pulled out. Therefore, although not shown in the drawings, the pressing member 12 is connected to the wedge tube 1.
By pressing the lead against the paper surface etc., if the lead holding force by the lead detent 4 is stronger than the force of the elastic member 5, the slider 2 will move back together with the lead. Since the chuck set 13 biting the core and the pressing member 12 integrated therewith also retreat, the pressing member 12 is released from the rear end surface 9 of the automatic stop pipe 6, and until then the pressing member 12 is killed by the repulsion of the pressing member 12. The tilting movement of the automatic stop pipe 6, which had been previously held, can be immediately brought to bear, and the above-described locking force due to friction can be generated. On the other hand, if there is a distance l between the rear end surface of the slider 2 and the front end surface of the pressing member 12, the same distance will be maintained even after the slider 2 is moved backward, so if the pressure from the paper surface etc. is suddenly removed, the slider 2 will be in the locked state. In order to continue, the chuck set 13 and the pressing member 12 move forward in an attempt to return to their original state, and eventually the pressing member 12 hits the rear end surface 9 of the inclined automatic locking pipe 6 and releases the lock. CHACK SET 1
Centering is performed by advancing 3, and each can return to its original state.

As mentioned above, centering using the tip notch is possible by forming the pressing member 12 at the front end of the wedge tube 15, but this makes centering using a new core in the wick tank inconvenient, so as shown in FIG. As shown in FIG. 2, the pressing member 12 and the wedge tube 15 are configured separately, and both can be moved back together in the backward direction when the tip is notched, and the pressing member 12 is stationary in the forward direction when the rear end is notched. The purpose of the present invention is to provide a structure that allows the chuck set 13 to advance even if the chuck set 13 continues to move forward. In FIG. 1, the inward protruding portion 19 of the pressing member 12 is slidably fitted into the rear cylindrical portion after the stepped portion 18 formed on the outer surface of the wedge tube 15, and the pressing member 12 is attached to the rear end surface of the automatic stop tube 6. This is why the front end surface of the wedge tube 15 is positioned with a certain distance from the pressing member 12 when it is in contact with the pressing member 9. Further, the rear end surface of the pressing member 12 is connected to the cylindrical receiving seat body 20.
A spring 22 is stretched between the rear step portion 1a of the shaft cylinder 1 and the rear end portion 21 of the cylindrical seat body 20 so as to push the protrusion 24 formed on the core tank 23 onto the seat body 20. A spring 25 is stretched between the front inner end surface of the receiving seat body 20 and the protrusion 24 so as to press against the rear end 21, and the wedge tube 15 is inserted at a slightly hard fitting point 26 of the core tank 23.
The chuck body 14 is connected to the chuck body 14 so as to be extendable and retractable, and can be pushed from the rear of the chuck body 14 by the pushing part 27 of the core tank 23, thereby making it possible to center the chuck body 14 by means of a rear end notch.

In the example shown in FIG. 1, a recess 2' is formed in the front outer surface of the slider 2, and the annular elastic body 28 is fixed to the recess 2'. Even when the slider 2 is moved forward and the core is released, the tip is notched and the slider 2 is retracted deeply so that the annular elastic body 28 is frictionally engaged with the inner surface of the automatic stopper tube 6.
As shown in FIG. 3, it is also possible to prevent unexpected centering caused by the back and forth movement of the slider 2.

As described above, the present invention provides an arrangement between the shaft tube 1 and the slider 2, which is elastically repelled forward by the resilient member 5, so that the slider 2 is biased so as to be tiltable about the point of contact with the inner surface of the shaft tube 1 as a fulcrum. In addition, when tilting, an automatic stop tube 6 is provided whose frictional resistance at the point of contact with the outer surface of the slider 2 is greater than the elastic force of the resilient member 5, and a rear end surface 9 of the automatic stop tube 6 is provided behind the automatic stop tube 6. A pressing member 12 that is capable of resiliency and release is disposed, and the automatic stop tube 6 is normally elastically repelled forward by the pressing member 12, and the pressing member 12 is moved back together with the chuck set 13 by pressing the core. Since it is connected to the chuck set 13 so as to move forward together with the chuck set 13 when the pressure of the core is removed, the slider 2 is caused by the frictional resistance of the automatic stop pipe 6 against the slider 2, which is tilted by the retreat of the pressing member 12. It is relatively easy to achieve a sharp advantage of locking the automatic stop tube 6, and the pressing member 12 can also straighten the posture of the automatic stop tube 6 by hitting the rear end surface 9 of the automatic stop tube 6 at an angle. Since it corrects and releases the lock, it is extremely excellent as a locking/unlocking device for the slider of a sharpener pencil with a tip.

[Brief explanation of drawings]

1 to 3 are sectional views showing the first embodiment of the present invention, in which FIG. 1 is in a normal state, FIG. 2 is in a state where the slider is pushed in, and FIG. 3 is in a state where the slider is locked. FIG. 4 is an explanatory diagram of the locking action of the present invention, and FIG. 5 is a sectional view showing a second embodiment of the present invention, which corresponds to FIG. 1. 1... Shaft tube, 2... Slider, 5... Elastic member, 6
...Automatic stop pipe, 12...Press member.

Claims (1)

[Claims] 1. Between the shaft cylinder 1 and the slider 2 which is elastically repelled forward by the resilient member 5, the slider 2 is biased so as to be able to tilt using the contact point with the inner surface of the shaft cylinder 1 as a fulcrum, and when tilted, the slider 2 Automatic stop pipe 6 whose frictional resistance at the contact point is greater than the elastic force of the elastic member 5
A pressing member 12 is provided at the rear of the automatic stop pipe 6 to allow the rear end surface 9 of the automatic stop pipe 6 to rebound and release.
The pressing member 12 moves backward together with the chuck set 13 due to the pressing of the core, and when the pressing of the core is removed, the chuck set 1
3. A locking/disengaging device for a slider of a sharp pencil at the tip, which is connected to a chuck set 13 so as to move forward together with the tip.