JP3823862B2 - mechanical pencil - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanical pencil in which a slide member is disposed in front of a shaft tube.
[0002]
[Prior art]
As an example, Japanese Utility Model Publication No. 57-38311 will be described. The utility model registration claim of this publication includes: “... the tip 2 having the second cavity 14 into which the chuck ring 5 is fitted, and the first cavity 10 on the outer periphery, It is provided with a core guide ring 11 holding a core guide pipe 12 on the tip side that is slidably press-fitted, and so on. That is, the core guide ring 11 always slides in the state where it is press-fitted in the first cavity 10.
[0003]
[Problems to be solved by the invention]
As described in the detailed description, the core guide ring is generally composed of a rubber-like elastic body. Therefore, the core guide ring is extremely hardened when the compressed state is extended for a long time (general Is also referred to as blooming phenomenon, deterioration, aging, etc.), which has hindered the lead-in / out action of the lead guide pipe and the lead-out action of the lead. That is, if the surface of the core guide ring is hardened, there is no sliding resistance with the tip, and the core guide pipe will inadvertently appear and disappear due to its own weight, or the core guide pipe will move easily. Therefore, the lead could not be extended.
[0004]
[Means for Solving the Problems]
The present invention is a mechanical pencil in which a slide member that is moved forward by a forward movement of a chuck body is disposed in front of a shaft cylinder, and the shaft cylinder and the slide member are moved back and forth in a state where sliding resistance is applied by pressure contact. However, the gist of the invention is that the sliding resistance is released by the non-pressure contact state in the retracted position of the slide member, and the forward and backward movements of the chuck body and the slide member are interlocked .
[0005]
[Action]
When the slide member moves forward, sliding resistance is applied, but at the retracted position, the sliding resistance is released.
[0006]
【Example】
A first example will be described with reference to FIGS. A core tank 2 is disposed in the shaft body 1 so as to be movable back and forth, and a chuck body 3 that can be opened and closed is fixed to the front end of the core tank 2. A chuck ring 4 that opens and closes the chuck body 3 surrounds the front portion of the chuck body 3. Further, an elastic member 5 such as a coil spring that urges these members rearward is stretched between the core tank 2 and the inner surface step portion 6 of the shaft tube 1. The lead tank 7, the chuck body 3, the chuck ring 4, the elastic member 5 and the like constitute the lead feeding means 7 of the present invention.
Further, a tip member 8 in which inner surface vertical ribs 8a are radially formed is detachably fixed to the front portion of the shaft main body 1 by means of screwing or the like. A projecting slide member 9 is slidably provided. Inside the slide member 9, there is a guide member 10 for guiding the core, and a core made of an elastic body such as silicone rubber or NBR that holds the core lightly in front of the guide member 10 and prevents the core from retreating. Although the detent member 11 is disposed, the guide member and the core detent member 11 may be integrally formed with the tip member. Further, a cylindrical portion 12 is formed behind the slide member 9, and a window hole 13 is formed in the cylindrical portion 12 at a position facing the cylindrical portion 12. In addition, a slit is formed in the cylindrical portion 12 so as to be connected to the window hole 13 and can be expanded by an elastic deformation force if an external action is applied to the cylindrical portion 12. A protrusion 14 formed on the front outer periphery of the chuck body 3 is loosely inserted into the window hole 13.
[0007]
An annular member (O-ring) 15 made of a rubber-like elastic body is attached to the outer peripheral surface of the intermediate portion of the slide member 9, but an elastic protrusion or the like may be integrally formed. When the slide member 9 is retracted (the state shown in FIG. 1), the annular member 15 does not sink into the inner surface vertical rib 8 a of the tip member 8, but performs an operation of feeding the core, and the slide member 9. When the head advances, the annular member 15 enters the inner surface vertical rib 8a. At this time, the annular member 15 is in pressure contact with the inner surface vertical rib 8a. That is, the slide member 9 moves forward in a state where sliding resistance is given by the annular member and the inner surface vertical rib.
Here, the sliding resistance force of the slide member 9 with respect to the tip member 8 (inner surface vertical rib 8a) is set so that the core is larger than the sliding resistance force with respect to the core detent member 11; It is set to be smaller than the elastic force of the elastic member 5 that urges the lead feeding means 7 and the like backward. That is, even if the lead moves forward together with the chuck body 3, the movement of the slide member 9 is restricted with respect to the tip member 8. Incidentally, the core holding force of the core detent member is preferably a value of 20 gf to 100 gf, and if it is smaller than this value, there is a risk that the core will slide down, and conversely, if it is high, the core cannot be drawn out. There is a risk of end. Further, the sliding resistance of the annular member 15 with respect to the tip member 8 is preferably 80 gf to 120 gf, and the elastic force of the elastic member 5 that urges the core tank 2 and the like backward is generally 500 gf to 600 gf. In this example, the annular member 15 is slidably contacted with the inner surface vertical rib 8a formed on the tip member 8. However, the annular member may be simply slidably contacted with the cylindrical inner surface instead of the inner surface longitudinal rib. In consideration of such unintentional deformation or air compression due to sliding, the rib shape is preferable.
A step 16 is formed behind the inner surface of the tip member 8. It is a restricting portion that prevents the chuck ring 4 from moving forward. When the chuck ring 4 comes into contact with the stepped portion 16, the chuck body 3 is expanded and the gripping core is released.
[0008]
Here, the distance until the chuck ring 4 contacts the step portion 15 is set to be smaller than the distance until the protrusion 14 of the chuck body 3 contacts the front end of the window hole 13 of the slide member 9. Yes. That is, after the chuck ring 4 comes into contact with the step portion 16 and the chuck body 3 expands, the protrusion 14 of the chuck body 3 comes into contact with the front end portion of the window hole 13. Specifically, the chuck ring contact distance is set to be shorter by about 0.2 mm than the chuck body contact distance. However, if the difference is about 0.1 mm to 1.0 mm, the chuck ring contact distance is sufficient. To do. By the way, although it functions even at 1.0 mm, the amount of protrusion of the core increases, and adjustment of the amount of protrusion of the core later becomes troublesome.
Further, a gap is formed between the vicinity of the cylindrical portion 12 of the slide member 9 and the shaft cylinder 1, but the gap is less than the fitting distance between the chuck body 3 and the slide member 9. Is set. That is, when the protrusion 14 of the chuck body 3 is loosely inserted (assembled) into the window hole 13 of the slide member 9, the cylindrical portion 12 near the window hole 13 is expanded, but the tip member 8 is assembled to the shaft cylinder 1. After that, the expansion of the cylindrical portion 12 is restricted, and the loose insertion state between the protrusion 14 and the window hole 13 is maintained. That is, the protrusion 14 does not come out of the window hole 13.
[0009]
A base 18 formed on the clip 17 is press-fitted and fixed to the rear part of the shaft body 1, and an eraser 19 is detachably attached to the rear part of the core tank 2. Reference numeral 20 denotes a knock cap that covers the eraser 19 and is detachably attached to the rear portion of the core tank 2. On the other hand, a grip member 21 made of a rubber material or the like is mounted in front of the shaft tube 1. The grip member 21 is mounted so as to straddle the recess 1a formed in the shaft tube 1 and the recess 8b formed in the tip member 8, and the tip member 8 is prevented from loosening with respect to the shaft tube 1, The front member 8 can be held with a finger up to the front.
[0010]
Next, the operation will be described. The state of FIG. 2 is a state in which the chuck body 3 is holding the core A. The slide member 9 is pulled backward by the protrusion 14 of the chuck body 3, and the annular member 15 is separated from the inner surface vertical rib 8a and is in a released state. That is, the compression force is not applied.
When the lead tank 2 is pressed forward from this state, the chuck body 3 together with the chuck ring 4 and the lead A held by the chuck body 3 move forward. At this time, since the core A is lightly held by the core detent member 11 of the slide member 9, the slide member 9 is also advanced, but the annular member 15 abuts the inner surface vertical rib 8a at the rear end, and In addition to the fact that the sliding resistance force of the slide member 9 with respect to the tip member 8 is set to be large, a large amount of instantaneous compression force (force for starting elastic deformation) is required to enter, so the slide member 9 is Without moving (see FIG. 3), the core A slides in the detent member 11 and protrudes from the tip of the slide member 9. Eventually, the chuck ring 4 comes into contact with the step portion 16 of the tip member 8, and its forward movement is restricted (see FIG. 4). At this time, a gap is formed between the protrusion 14 of the chuck body 3 and the front end of the window hole 13 of the slide member 9. Here, when the lead tank 2 further advances, the chuck body 2 brings the protrusion 14 of the chuck body 3 into contact with the front end of the window hole 13 while slightly moving the lead A (see FIG. 5). At this time, the chuck body 3 is expanded and the gripped core A is released. However, the chuck body 3 may be expanded at the moment when the chuck ring 4 comes into contact with the step portion 16.
When the lead tank 2 further advances, the protrusion 14 of the chuck body 3 moves the slide member 9 forward. At this time, the slide member 9 moves forward while applying sliding resistance by the pressure contact action between the annular member 15 and the inner surface vertical rib 8a. In this example, the sliding resistance force is set to be extremely small. Also good. In the case of this example, the regulation (blocking) action at the moment when the annular member 15 enters the inner surface vertical rib 8a is the most important operation. Therefore, the frictional force (sliding resistance force) at the moment of compression is used. As a result, deterioration over time due to compressive deformation of the annular member can be prevented.
Eventually, the intermediate step portion 22 of the slide member 9 comes into contact with the rear end portion 23 of the inner surface vertical rib 8a of the tip member 8, and its forward movement is prevented (see FIG. 6).
[0011]
Here, when the forward movement of the lead tank 2 is canceled, the chuck body 3 is retracted in an expanded state, but the slide member 9 is not retracted because resistance is applied by the annular member 15. Eventually, when the protrusion 14 of the chuck body 3 comes into contact with the rear end of the window hole 13 of the slide member 9 (see FIG. 7), the backward movement of the slide member 9 is started. Eventually, the chuck body 3 is closed by the chuck ring 4 and grips the core A again (see FIG. 2).
Further, since the window hole 13 of the slide member 9 is engaged with the protrusion 14 of the chuck body 3, the retracted position continues to be maintained even after the pressing operation is released, and the trailing core is dropped by its own weight. A gap is not formed between B and the remaining core A.
[0012]
A second example will be described with reference to FIGS. This is an example in which the sliding resistance with respect to the inner surface vertical rib 8 a of the slide member 9 is given by an elastic protrusion integrally formed with the slide member 9. More specifically, an elastic piece 25 formed by a U-shaped notch (notch portion 24) is formed on the side surface of the intermediate cylinder portion of the slide member 9 at a position facing the elastic piece 25. A protrusion 26 is formed on the outer side. This protrusion 26 corresponds to the annular member 15 of the previous example. The projection 26 is also released at the position where the slide member 9 is retracted, and by moving forward, the protrusion 26 sinks into the inner surface vertical rib 8a and imparts sliding resistance. Other configurations, operations, and the like are substantially the same as the premise, and thus the description thereof is omitted.
A third example will be described with reference to FIG. This is an example in which the present invention is applied to a general mechanical pencil. As in the first example, an annular member 15 is attached to the intermediate portion of the slide member 27. When the slide member 27 is retracted, the annular member 15 is positioned behind the inner surface vertical rib 8a. Yes. That is, the annular member 15 is in a released state. From this state, when the lead feeding operation is performed, the slide member 27 is pressed and advanced at the front end portion of the chuck body 3, and at this time, the annular member 15 enters the inner surface vertical rib 8 a and imparts sliding resistance.
[0013]
【The invention's effect】
The present invention is a mechanical pencil in which a slide member that is moved forward by a forward movement of a chuck body is disposed in front of a shaft cylinder, and the shaft cylinder and the slide member are moved back and forth in a state where sliding resistance is applied by pressure contact. However, at the retracted position of the slide member, the sliding resistance is released due to the non-pressure contact state, and the chuck body and the slide member are linked in advance / retreat operation, so that the function of the slide member is extended for a long time. Without losing it, the core can be fed out over a long period of time.
[Brief description of the drawings]
FIG. 1 is a longitudinal half sectional view showing a first example.
FIG. 2 is an enlarged view of a main part with the core attached to FIG.
FIG. 3 is a longitudinal sectional view showing a main part of the operation.
FIG. 4 is a longitudinal sectional view of an essential part showing the operation.
FIG. 5 is a longitudinal sectional view of the main part showing the operation.
FIG. 6 is a longitudinal sectional view of an essential part showing the operation.
FIG. 7 is a longitudinal sectional view showing a main part of the operation.
FIG. 8 is a longitudinal sectional view of an essential part showing a second example.
FIG. 9 is a front view showing a slide member of a second example.
10 is a side view of FIG. 9. FIG.
FIG. 11 is a longitudinal sectional view of an essential part showing a third example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 axis | shaft main body 1a Recessed part 2 Core tank 3 Chuck body 4 Chuck ring 5 Repellent member 6 Inner surface step part 7 Core feeding means 8 Tip member 8a Inner surface rib 8b Recessed part 9 Slide member 10 Core detent member 11 Groove part 12 Cylindrical part 13 Window Hole 14 Projection 15 Ring member (O-ring)
16 Stepped portion 17 Clip 18 Base 19 Eraser 20 Knock cap 21 Grip member 22 Intermediate stepped portion 23 Rear end portion 24 Notched portion 25 Elastic piece 26 Protrusion 27 Slide member

Claims (3)

A mechanical pencil in which a slide member that is moved forward by the forward movement of the chuck body is arranged in front of the shaft cylinder, and the shaft cylinder and the slide member move back and forth in a state in which sliding resistance is applied by pressure contact. The mechanical pencil is characterized in that the sliding resistance is released by a non-pressure contact state at the retracted position of the member, and the forward / backward movement of the chuck body and the slide member is interlocked .   The mechanical pencil according to claim 1, wherein an annular member made of a rubber-like elastic body is disposed between the shaft cylinder and the slide member, and the sliding resistance is provided by the annular member.   A chuck body for gripping and releasing the core is disposed behind the slide member, and a chuck ring for opening and closing the chuck body is surrounded in front of the chuck body, and a protrusion is formed on the outer surface of the chuck body. The protrusion is loosely inserted into the window hole formed in the slide member, and the movement distance of the chuck ring is made smaller than the distance that the protrusion of the chuck body moves the window hole of the slide member. The mechanical pencil according to claim 1.

Images