JPS6345320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a tip notch that is devised so that the centering length obtained by one tip notch operation is always a constant length, regardless of the length of the tip protruding before the tip notch. Regarding formula sharpening pencils.

The tip-knot type sharp pencil presses the core tube of the slider or the protruding core against the paper surface, and the slider holding the core by the lead-carrying member and the chuck set biting the core are moved back together, and then Centering can be achieved by removing the pressure and changing the mutual positional relationship between the slider and the chuck set when returning them to their original states. However, in this case, the centering length depends on the protruding length of the core before the tip notch and cannot be made constant. One method for centering a fixed length is to press the core so that the core protruding from the core tube is pulled in so that it is flush with the end surface of the core tube, and to perform centering of a fixed length from this situation. It is to be. However, since the protruding length of the lead to be retracted differs each time, the degree of deviation between the slider and the chuck set when the lead is pressed against the paper surface will change each time. It is necessary to develop a mechanism that enables constant length centering.

The purpose of the present invention is to provide a sharpening pencil with a tip that can meet the above-mentioned needs.
This was done for that purpose.

In order to achieve the above object, the present invention aims to prevent the core from protruding from the core tube by allowing the slider to retreat beyond a certain pushing length when the core is pressed by the tip notch, but the chuck set that bites the core can retreat further than that. In the intermediate process of retracting the core and returning it to its original state by stopping the pressing of the core, a reference state is created that enables constant length centering, and even the difference in the return length between the chuck set and the slider after that is This enables fixed-length centering that is independent of the core protrusion length, which is the intended purpose, and will be explained below with reference to the embodiment shown in the drawings.

The slider 2 has a core tube 3 at the tip and a core detent 4 inside, and the slider 2 has an overhang 5 and a shaft tube 1.
A steady position is determined by pressing the front end surface of the overhanging portion 5 against the inner step end surface 1a of the shaft tube 1 by the elastic member 7 for the slider stretched between the front end surfaces of the member 6 fixed to the inside of the slider. When the lead is pushed in by the notch, the elastic member 7 can be compressed and retreated via the lead detent 4 that holds the lead, and the retraction stop position is when the rear end surface of the overhang 5 hits the end surface of the member 6 or when the elastic member 7 7
It is determined by when it shrinks to its full capacity. In the figure, l indicates the retractable length of the slider 2.

The chuck set 8, which holds and releases the core, is made up of a chuck elastic member 11 stretched between the chuck body 9 and the wedge tube 10, and a rolling element 12 interposed therebetween, so that the chuck set 8 holds and releases the core. Against a force that pushes the core into the barrel 1, the wedge effect is further strengthened to increase the core clamping force, but against a force that pulls out the wedged core from inside the barrel 1, the wedge effect is strengthened. Since the chuck body 9 attempts to move forward along with the chuck, the wedge effect weakens and the mouth of the chuck opens slightly to allow the core to be pulled out.

Now, in the present invention, a slider push pipe 14 is provided between the shaft cylinder 1 and the chuck set 8, which is slidable in the front-rear direction on the inner surface of the shaft cylinder 1 and is constantly pushed forward by a slider push pipe spring 13. .
The steady position of the slider push tube 14 is determined by pressing the push portion 15 formed at the front part of the slider push tube 14 against the rear end surface of the member 6, for example. When the slider 2 and the slider push pipe 14 are both in the normal position, the rear end surface of the slider 2 and the slider push pipe 14
It is separated from the front end surface of the push portion 15 and forms a distance m. The slider push tube 14 can be retreated only by being pushed by the slider 2, and its retreat length is therefore uniquely determined as (l-m).

The wedge tube 10 of the chuck set 8 described above is fitted into the inner surface of the slider push tube 14 so as to be freely slidable. The wedge tube 10 is constantly pushed backward by a push spring 16 interposed between it and the slider push tube 14, while the wedge tube 10 is pushed backwards by a push spring 16 that is stronger than the push spring 16 via a dowel tube 18 that abuts the rear end surface of the wedge tube 10. It is pushed back by the force of the spring 17. The protrusion 19 formed on the dowel tube 18 is placed in the regulation groove 20 of the slider push tube 14, and the steady position of the wedge tube 10 is determined by pressing the protrusion 19 of the dowel tube 18 against the front end surface of the regulation groove 20. . At this time, a gap n is formed between the rear end surface of the protrusion 19 and the rear end surface of the regulating groove 20. In other words, determining the normal position of the wedge tube 10 means determining the normal position of the chuck set 8. When the protruding length of the core from the core tube 3 is x, the chuck set 8 when the tip is notched is
As will be described later, the retraction length is (x+l), which is an additional (x+m) retraction than the slider push pipe 14, so the value of n should be determined to satisfy n>x+m. A dowel 21 is formed on the surface of the dowel tube 18 and can be freely engaged with a stepped portion 23 of a locking ring 22 fixed in the shaft cylinder 1. Dowel 21 is stepped part 23
The difficulty of coming off from the center can be set in any way by changing the strength of the springs 13 and 17, but this will affect the method for determining the centering length, as will be described later.

The rear end of the dowel tube spring 17 that pushes the dowel tube 18 is supported by the front end surface of the protrusion 25 of the core tank 24, and by pressing the rear end surface of the protrusion 25 against the inner step end surface 1b of the shaft tube 1, the core tank 24 is The steady position is determined. A pressing member 27 having a raised portion 26 is attached to the core tank 24, which is movable in the front-rear direction, to enable centering by a rear end notch. When the core tank 24 is moved forward, the protruding portion 26 directly contacts the wedge tube 10 regardless of the dowel tube 18, and the front end surface of the wedge tube 10 advances until it collides with the push portion 15 of the slider push tube 14. It fits into the inner surface of the wedge tube 10 with relatively strong sliding abrasion resistance, and eventually the tip of the pressing member 27 can press the chuck body 9 to open the chuck.

Next, the operation when the tip is knocked when the structure is as described above will be explained.

When pressing the tip of the core that protrudes a length x from the core tube 3 against the surface of the paper, the rear end surface of the slider 2 is retracted by the length m that hits the pusher part 15 of the slider pusher tube 14. 4, the chuck set 8 holding the core, and the dowel tube 18 pressed against the rear end surface of the wedge tube 10 move back together (see FIG. 2). After the slider 2 comes into contact with the pushing part 15 of the slider push tube 14, the slider 2 comes to rest by making the force of the slider push tube spring 13 stronger than the core holding force of the core detent 4. , the core, the chuck set 8 and the dowel tube 18 are moved back together to make the core and the core tube 3 flush (see FIG. 3).
In this way, when the core tube 3 is directly pressed against the paper surface, the core, slider 2, chuck set 8, slider push tube 14, and dowel tube 18 move back together, and the projecting portion 5 of the slider 2 is pushed against the front end of the member 6. The core pushing process is completed when the slider reaches the retracted stop position where it hits the surface (see Figure 4). During this time, the slider 2 has a length l, and the slider push pipe 14 has a length (l-
m), and since the core, chuck set 8, and dowel tube 18 are (x+l), in other words, they will move back an extra amount (x+m) than the slider pusher tube 14, so when the core push-in is completed, as shown in Fig. 4. To,
The dowel 21 of the dowel pipe 18 is connected to the step 2 of the locking ring 22.
3, and a slight gap is created between the protrusion 19 of the dowel tube 18 and the rear end surface of the regulating groove 20.

Next, stop pressing the core and return each to its original state. In the middle of the return process, the dowel 21 of the dowel tube 18 comes into contact with the stepped portion 23 of the locking ring 22, and the protrusion 19 of the dowel tube 18 comes into contact with the rear end surface of the regulating groove 20, as shown in FIG. do. In the present invention, this state is used as the starting point for constant length centering regardless of the core protrusion length. The operation after this standard state is reached can be divided into the following two modes depending on the difficulty of the dowel 21 coming off the stepped portion 23, which can be set in any way depending on the strength of the springs 13 and 17 described above. The first mode is a case where the strength of the springs 13 and 17 is increased so that the slider 2 moves forward and the dowel 21 disengages at the same time, and in this case, the slider push pipe 14
The dowel pipe 18, slider push pipe 14, slider 2,
The chuck set 8 and the core move forward together, and then the slider 2 moves forward by a length m, while the chuck set 8, which has bitten the core, moves forward by a length n, so the centering length L from the core tube 3 is ( nm). In the second mode, the strength of the springs 13 and 17 is weakened so that the slider 2 returns to its original state, and then the dowel 21
In this case, the lead can be pulled out of the chuck set 8 by the lead holding force of the lead detent 4 of the slider 2, so when the slider 2 returns to its original state, the lead will be removed. The tip of core tube 3 remains flush, and then chuck set 8
To return to its original state, it moves (p+n), so
The centering length L from the core tube 3 is (p+n) (sixth
(see figure).

In addition, in the operation when the rear end is knocked, as described above, the moving length in which the front end surface of the wedge tube 10 hits the pushing part 15 of the slider push pipe 14 by the raised part 26 of the pushing member 27 becomes the centering length, and then the pushing member The tip of the chuck 27 pushes the chuck body 9 to open the chuck's mouth and then retreats. During the retreat process, the chuck's mouth opens due to the action of the protrusion 26 that fits on the inner surface of the wedge tube 10 with relatively strong sliding friction resistance. As the raised portion 26 separates from the inner surface of the wedge tube 10, the chuck mouth closes due to the force of the chuck elastic member 11, and bites the core again.

As is clear from the above description, the present invention provides a slider 2 equipped with a core detent 4 and a slider push tube 14 equipped with a push part 15 that can come into contact with the rear end surface of the slider 2, respectively. The slider push tube 1 is provided in the shaft tube 1 so as to be movable back and forth so as to be resiliently directed and to maintain a predetermined interval at each steady position.
The wedge tube 10 of the chuck set 8 which is in an elastic relationship with each other is slidably inserted into the inside of the slider push tube 14, and the rear end of the wedge tube 10 has a regulating groove 20 formed in the slider push tube 14. The protrusion 19 disposed inside and the locking ring 22 fixed inside the shaft cylinder 1.
Since the dowel tube 18 having the dowel 21 that can be freely engaged with the stepped portion 23 is disposed and elastically resilient toward the front, the chuck set 8 that bites the core can press the protruding core into the core when the core is pressed. It can be retracted so that it is flush with the end surface of tube 3, and when the core is released, the 5th
As shown in the figure, a reference state for constant length centering in which the dowel tube 18 moves forward and the dowel 21 of the dowel tube 18 comes into contact with the step 23 of the locking ring 22 can be created in the intermediate process of returning. It is extremely superior in that it allows for constant length centering.

[Brief explanation of the drawing]

FIGS. 1 to 6 are cross-sectional views showing embodiments of the tip-knob type mechanical pencil according to the present invention, and are drawn in the order of operation. 1...Shaft cylinder, 2...Slider, 4...Core detent,
8...Chuck set, 10...Wedge tube, 14...Slider push tube, 18...Dowel tube, 19...Protrusion, 20...Regulation groove, 21...Dowel, 22...Lock ring, 23...Step part.

Claims (1)

[Claims] 1. The slider 2 equipped with the core detent 4 and the slider push pipe 14 equipped with the push part 15 that can be attached to the rear end surface of the slider 2 are elastically repelled forward, respectively, and are moved to a predetermined position at each normal position. The wedge tube 10 of the chuck set, which is provided in the shaft cylinder 1 so as to be able to move back and forth so as to maintain the spacing, and which is in an elastic relationship with the slider push tube 14, is slidably inserted inside the slider push tube 14, and the wedge tube 10 is slidably inserted into the slider push tube 14. At the rear end of the tube 10, a protrusion 19 disposed in a regulating groove 20 formed in the slider push tube 14 and a stepped portion 23 of a locking ring 22 fixed in the shaft cylinder 1 are engaged when the core is pressed and released. A tip-knot type sharp pencil in which a dowel tube 18 having a freely movable dowel 21 is disposed and is elastically repelled toward the front.