JPH0667679B2 - Mechanical pencil with fluid pressure mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention does not hold the core when not in use, and when writing, the core is held by the natural force of pinching the shaft with a finger, and the core remains in the written state. The present invention relates to a mechanical pencil having a fluid pressure mechanism capable of feeding a lead from the tip without changing the positions of fingers and separating the wrist from the paper surface only by pinching the shaft or loosening the pinching force.

(Prior Art) An automatic lead-out mechanical pencil currently on the market is provided with a so-called ball chuck having a function of advancing and retracting elements and a spring, as disclosed in Japanese Patent Laid-Open No. 58-201696. It is used in combination with a sliding body (also called a slider) that has the function of pulling the core forward from the ball chuck by lightly holding the core forward with. There is an effect of automatic centering in which writing can be continued without performing any operation other than the writing operation of pinching and writing.

However, in such an automatic lead-out mechanical pencil, since the sliding body is constantly urged forward by the spring, the tip of the core pipe, which is a part of the sliding body, is constantly pushed by the force of the spring during writing. Since it hits the paper surface and rubs against the paper surface, the writing feeling is bad, and in addition, the ball chuck requires strict accuracy in manufacturing, and the assembly work efficiency is also poor.
There is a defect that the manufacturing cost becomes high.

Therefore, the present applicant says that a writing instrument is one that is pinched and written with fingers, and that when the writing pressure is strong, the shaft is strongly pinched, and when the writing pressure is weak, the shaft is slightly pinched and the writing is performed. Focusing on that, squeeze the shaft with your fingers and pinch it with your fingers to displace it in the radial direction to release the fingers or loosen the gripping force and place the knob to restore it to its original position. A chuck and a fastener are provided inside the main body so that they move in an axial direction in conjunction with each other.The chuck and the fastener are not fitted to each other when the knob force is not applied to the knob, and the core is held. In the released state, and when a knob force is applied to the knob part, the chuck and the fastener are fitted so that the core is pinched,
By arranging the chuck and fastener so that they can move relative to each other, pinch the knob and loosen the pinching force to move the chuck and fastener relatively in the axial direction, and fit the fastener and chuck. We have developed various mechanical pencils called the knob type that can be detached to let out the lead.

For example, JP-A-53-145735, which is a knob type prototype
In the one disclosed in Japanese Patent Publication No. 9-45, first, one of the fastener and the chuck is moved forward by pinching the knob, and the fastener and the chuck are engaged with each other to hold the core, and the knob is further firmly pinched. By doing so, the tightened fasteners
By moving the chuck forward together with the core and letting out the core, relieve it by loosening the gripping force on the knob part, and further by loosening the force gripping the knob part, first retract the clamp and the chuck in the fitted state together. Further, by loosening the gripping force of the knob, either the chuck or the fastener is retracted to separate the chuck and the fastener to release the nipping and the slider with the nib holding lightly holds the nib. It is designed so that the released lead can be pulled out from the chuck by its own weight.
No. 21586 (Japanese Patent Application No. 60-246683, the application is changed), the chuck is retracted by pinching the knob portion, and the chuck is engaged with the fastener that is prevented from retracting, thereby performing core holding. The chuck is moved forward by loosening the gripping force of the knob, and the lead is extended by the advanceable distance of the fastener. Furthermore, Japanese Patent Application No. Sho 60-218034
The one disclosed in the specification has a function of preventing forward and backward retraction without using a complicated core holding mechanism such as a ball chuck, and has a uniform effect on the automatic core feeding mechanism, and moreover, the knob portion is pinched. When not in use, the pinching of the core is released.

The knob type mechanical pencil described above can hold the core firmly for writing by pinching the knob part arranged in the front part of the shaft with a force that can withstand the writing pressure, and during the writing By loosening the force of your fingers and pinching the force, and then pinching it again, you can pull out the core from the tip of the body such as the core pipe, and you can write with the tip of the core visible, and use the knob on the knob. When the core is overloaded due to frequent application of force or loosening of the pinching force, the core that is overloaded with no knob force applied to the knob can be pushed back by simply applying it to the paper surface, etc. In order to draw out, you do not need to do any operation other than writing by pinching or loosening the pinching force of the axis, so there is no inconvenience of re-holding the axis, It was not even the fact that the core is broken or in shock because it is not pinched when not in use. As described above, the knob type mechanical pencil does not have the above-mentioned defects of the conventional automatic lead-out type mechanical pencil, and has a similar effect to the automatic lead-out.

(Problems to be Solved by the Invention) The above-mentioned knob type mechanical pencil has no drawbacks in principle as described above, but in the course of its development, It turns out that there are two problems. In other words, by engaging and disengaging the fastener and the chuck, the core is securely held and released while the grip is released, and the core slip phenomenon is sufficiently endured against the writing pressure. To securely hold the lead and completely release the hold, a lead holder,
A stroke is required to move the chuck and the fastener relative to each other in the axial direction.

However, the above-mentioned Japanese Patent Laid-Open Nos. 53-145735 and 56-21
In each of the publications of No. 586, since a part of the knob portion that hits the fastener or the chuck and presses the fastener or the chuck is configured as a cam, the force of pressing the pressing member when the inclination angle of the cam surface is increased. Is weak, the stroke for pushing the fastener forward becomes small, and if the inclination angle of the cam surface is made small, the stroke for pushing the fastener forward becomes large but the force for pressing the holding member becomes large. Therefore, in order to obtain a large stroke with a weak force, it is necessary to increase the radial displacement of the presser member, but if this is done, the presser member will greatly extend from the shaft of the main body to the outside and the design It gets worse.

Further, in the specification of Japanese Patent Application No. 60-218034, the one using the chevron-shaped pressing member having the hinge at the central portion as shown as an example, a relatively large stroke can be obtained, The restoring force of the presser member to restore is extremely small, and it has an advantage that it quickly restores when it starts to restore, but it has a problem that it is difficult to scribble.

As described above, according to the conventional force transmission means for pinching the knob portion in the radial direction and pushing the axial moving body in the axial direction with the knob portion, the functions of pinching the core, releasing the core, and extending the core are achieved. If it is attempted to secure it sufficiently, the knob part would be protruded from the main body to the outside, and the external appearance would be deteriorated, and it was difficult to write on it.

According to the present invention, when the knob portion is pinched, the fastener and the chuck are fitted to each other to securely hold the core, and when the force of pinching the knob portion is loosened, the fastener and the chuck are separated from each other. In addition to completely releasing the grip of the, while applying the knob force or loosening the knob force in the writing state, that is, the state that the writing instrument is pinched with the finger, the diameter of the core can be reliably extended. Stroke when the three parts of the lead holder, the chuck, and the fastener that are pushed by the knob when the knob that is displaced in the direction is held by the knob and that always holds the lead with a certain amount of force, move relative to each other in the axial direction. Can be sufficiently obtained, therefore, like the conventional writing instruments, the part to be pinched by the fingers can also be in a cylindrical shape, and therefore can be swirled, and can have an appearance form almost similar to that of a conventional writing instrument, Besides, , The core of clamping, release, and a technical problem to achieve a transmission means of the forces can ensure the function of feeding of the core.

(Means for Solving Problems) According to the present invention, the front portion of the main body is axially moved with respect to each other so as to hold and hold the lead when engaged and disengaged, and to release the clamp of the lead when released. A chuck that has a chuck and a fastener for holding the lead, a lead holder that always holds the lead with a certain amount of force in front of the chuck, and a lead feeding mechanism that includes the lead holder, the chuck, and the fastener. In the pencil, a knob portion is provided on the outer circumference of a portion to be pinched by a finger when writing on the main body, and the knob portion has an annular shape which is displaceable and deformable in the radial direction and has a through hole for transmitting fluid pressure to one side in the axial direction. A fluid chamber is arranged, the fluid chamber is filled so that fluid does not leak, and axial movement means is provided in series through the through hole, and the axial movement means is interlocked with the lead-out mechanism of the lead. Then, when you apply the knob force to the knob part The fluid chamber is displaced and deformed in the radial direction, and at least the chuck and the fastener of the lead-out mechanism for the core are axially actuated via the axial movement means,
The feature is that the knob force is restored when loosened or pulled out.

Regarding the axial operation of the lead-out mechanism including the above-mentioned chuck, fastener, and lead holder, the lead holder is fixed to the main body, and the chuck and fastener move relative to each other. The core is extended by fitting, and the core holder is not fixed to the main body but is provided in the sliding body that can move in the axial direction. There are those that move out to move the core. Therefore, there are various lead-out orders such as the lead-out, pinching, advancing, and releasing sequences, and the lead advancing, pinching, delivering, and releasing sequences.

In addition, the knob part is formed in a cylindrical shape so that it can be scribbled and easy to hold, and the feel when the cylindrical knob part is made of elastic material such as rubber, plastic, or fiber is held. It is also possible to reduce the number of parts by improving the efficiency and preventing the pen from being crushed, or by using the knob portion as the outer peripheral wall of the fluid chamber.

(Operation) Since the present invention is configured as described above, when a gripping force is applied to the gripping portion of the main body with a finger when writing, the gripping portion is displaced and deformed in the radial direction, and the gripping portion is located inside the gripping portion and is in the axial direction. Although the volume of the annular fluid chamber having the through hole for transmitting the fluid pressure to the side decreases and the pressure of the fluid inside rises, the fluid chamber is formed in the annular shape in the knob portion, and the axial direction Since it is formed to be shorter in the radial direction compared to, when a knob force is applied to the knob part, the portion corresponding to the change in the radial volume of the fluid in the fluid chamber tries to move in the axial direction, At least a chuck for a lead-out mechanism including a chuck, a fastener, and a lead-holding device is produced via the through-hole provided so as to efficiently actuate the axial-movement means. And operate the fastener efficiently in the axial direction. Before these three move together, the chuck and fastener are not in mating condition and therefore the core is not pinched, but when these three move relatively axially, the chuck and fastener are And are in a fitted state, and the lead is held. Also, when the knob force is loosened or pulled out, the spring force, the restoring force of the fluid chamber, or both cause the above three members to move in the axial direction to restore the original position before starting, and the chuck and the fastener are re-engaged. When separated, the pinching of the lead is released.

The lead retainer, chuck, and fastener used in this mechanism can be the same as those used in conventional knock-type mechanical pencils and can be used as is without using a complicated mechanism such as a ball chuck. The purpose is to allow forward movement and prevent backward movement. Then, the three members of the chuck, the fastener, and the lead holder relatively move with each other, so that the lead can be reliably fed out, held, advanced, and released.

Since the writing is carried out while holding the core extended in front of the main body, it is possible to write with the tip of the core visible, and the writing is good.

The nipping of the core during writing is performed by pinching the knob, so the nipping force of the nib is affected by the pinching force, but when the writing pressure is strong, the pinching force also becomes strong, and when the writing pressure is weak, Since the force to pinch naturally also becomes weak, the core will be pinched by the chuck with an appropriate pinching force according to the fluctuation of the writing pressure strength, and in combination with the core pinching function due to the wedge effect between the chuck and the fastener. In the mechanical pencil according to the present invention, the lead is always firmly held against the writing pressure.

When not in a writing state, the chuck and fasteners are in a disengaged state, and the lead is not held by the chuck, but it is held by the lead retainer with some force, so the lead falls off under its own weight. There is no.

(Example) Next, the Example of this invention is described with drawing.

1 to 6 are longitudinal sectional views showing a mechanical pencil showing a first embodiment of the present invention in the order of operation. In FIG. 1 showing a state when the knob portion is not pinched and not used,
Reference numeral 1 is a shaft, 2 is a mouthpiece, and the shaft 1 and the mouthpiece 2 are connected by an intermediate joint 3. The small-diameter portion 4 forming the middle portion of the joint 3 is used as the inner peripheral wall, and the outer peripheral wall 5 is formed of an elastic member such as rubber or plastic, or a flexible member. An annular fluid chamber 6 having a through hole for transmitting a fluid pressure to the side is provided in a portion of the main body which is pinched by a finger when writing.

The outer peripheral wall 5 is used as a knob portion so that the outer peripheral wall 5 is deformed and displaced in the radial direction (inwardly) when the finger is pinched, and the volume of the fluid chamber 6 is reduced. The front end periphery and the rear end periphery of the knob portion are tightly pressed by the rings 8 and 9 to the front portion and the rear portion of the joint, respectively. The base 2, the joint 3, the fluid chamber 6, and the shaft 1 form a main body. One or more (three in the figure) cylinder chambers 11 are provided so as to communicate with the fluid chamber 6 in the enlarged portion 10 at the front of the joint 3, and these cylinder chambers 11 each have an axial moving means. As the piston 12a is inserted,
The rear end surface of the piston 12a is in contact with the fluid chamber 6 through the through hole. Therefore, when the pressure in the fluid chamber 6 rises, the piston 12a is pushed forward by the fluid and moves forward.

Inside the main body, a chuck 13, a fastener 14, and a slide body 17 as a core holder having a core holder 15 for constantly holding the core with a certain amount of force are provided so as to move axially relative to each other. There is.

The chuck 13 is formed by dividing the front portion into two and three (three in the figure), and is given an outward opening force.

The core case 18 is connected to the rear of the chuck 13 and the core case 18 is connected.
May be fixed to the shaft 1, but the outer peripheral wall 5 is pinched and the chuck 14 is moved when the fastener 14 is advanced as described later.
13 is not fixed to the shaft 1 so as to be able to elastically move forward, and is biased rearward by the spring 19 so that the shaft 1 is constantly moved.
It hits the rear step inside.

The core holder 15, which is made of rubber or the like and holds the core with a certain amount of force, is press-fitted into the central recess on the rear end side of the cylindrical body portion 20 that forms the central portion of the sliding body 17, and the cylindrical body portion 20. From this, one or a few feet (three in the figure) of feet 21 extend radially outward. The rear end surface of the foot 21 is in contact with the front end surface of the piston 12a.

The sliding body 17 is always urged in the backward direction by the other end of the spring 22 whose one end is received by the step portion in the base 2. Therefore, the piston 12a is pushed forward by the pressure fluid in the fluid chamber 6 and pushes the sliding body 17 forward, while the sliding body 17 is pushed backward by the spring 22 and moves the piston 12a backward. Pushing. This spring 2
The force of 2 may be such that the chuck 13 and the fastener 14 can be disengaged.

The front portion of the fastener 14 is provided with the same number of slits 23 as the legs 21, and the legs 21 of the sliding body 17 penetrate the slits 23, and the sliding body 17 and the fastener 14 move axially relative to each other. However, since the stopper 25 is attached to the front end of the fastener 14, the two can move relative to each other by the length indicated by l in the figure.

The core pipe 26 that extends forward from the front end of the sliding body 17 is
The front end of the core pipe 26 is located slightly rearward of the front end of the mouthpiece 2, and the core pipe 26 is completely housed in the main body.

The outer peripheral wall 5 serving as a knob has almost no self-restoring force, and the piston 12a is also retracted until the sliding body 17 hits the front end face of the small-diameter portion 4 of the joint 3. A stopper may be provided to determine the final retracted position of the feeding piston 12a.
Further, an O-ring is interposed between the cylinder chamber 11 and the piston 12a to prevent fluid leakage. Even if the piston 12a is extended rearward to make it longer and the piston 12a is always in contact with the inner peripheral surface of the cylinder chamber 11, fluid leakage can be prevented.

In addition, 27 is an eraser, and the eraser 27 is removed and a new lead is replenished. A sloping surface 28 for guiding the lead is provided in the front of the lead case 18. A protrusion 29 is provided on the rear outer periphery of the lead case 18, and the lead case is biased in the backward direction by the above-mentioned spring 19 inserted between the protrusion 29 and the ring 30 press-fitted on the inner peripheral surface of the main body. A step 31 is provided inside the rear of the main body so that the convex portion 29 abuts rearward so as to prevent the backward movement of the 18 further.

In assembling, the shaft coupling 3, the fluid chamber 6 and the piston 12a are assembled as a unit, the core case 18 with the chuck 14 attached to the shaft 1 is inserted, and the spring 19 is inserted.
Press the ring 30 in and press the assembled unit into the shaft 1
Then, the unit in which the sliding body 17 with the fastener 14 and the core pipe 26 attached and the stopper 25 are assembled is attached to the core 32.
Insert it into the chuck from the front, and screw the base 2 with the spring 22 attached to the shaft coupling 3 to connect it.
Put the wick 32 in the wick case 18 and fit the eraser 27 to complete the assembly.

Next, the operating state from FIG. 1 will be described.

FIG. 1 shows a state in which the outer peripheral wall 5 serving as a knob portion is not pinched at all, and the fastener 14 is separated from the chuck 13 by a distance L, and the fastener 14 and the chuck 13 are separated from each other.
And are completely separated. The fastener 14 has a rear end of a slit 23 provided at a front portion thereof, which is brought into contact with a rear end of a foot 21 and is prevented from advancing by its own weight. In this state, the chuck 13 is opened by its own expanding force, and the core 32 is not held. Although the tip of the core 32 reaches the tip of the core pipe 26, the method of bringing the first pipe to this state will be omitted because it is apparent from the following operation description.

FIG. 2 shows that the outer peripheral wall 5 is slightly pinched, the volume of the fluid chamber 6 is slightly reduced, the pressure of the fluid is increased, and the piston 12a as an axial moving body is slightly advanced by being pushed by the fluid.
The sliding body 17 having the lead holder 15 pushed by 2a is a spring.
It shows the state when moving forward with the 22 shortened. In the state of FIG. 2, the sliding body 17 and the fastener 14 are advanced, and therefore, in FIG. 2, the sliding tool having the core holding tool 15 of the fastener 14, the chuck 13, and the sliding body 17 is shown in FIG. The moving body 17 and the fastener 14 are advanced, and the lead pipe 26 and the lead 32 are also advanced by that amount, but the chuck 13 is not advanced. Also, the fastener 14 is moving forward under its own weight.

In FIG. 3, the outer peripheral wall 5 is gripped a little more, and the piston 12a is advanced a little like the above, and is pushed by this piston 12a, the spring 22 is contracted while pushing the stopper 25, and the sliding body 17 is further tightened. It shows a state in which the fastener 14 and the chuck 13 are completely fitted together and the lead 32 is held by being advanced together. At this time, the chuck 13 has not advanced.
During the transition from the state of FIG. 2 to the state of FIG. 3, the wick 32 moves a further distance L together with the wick pipe 26, and the wick 32 remains inside the wick pipe 26 and the wick 32 of the base 2 together. It projects a distance L from the tip. Thus far, the lead pipe 26 and the lead 32 have moved forward together with the sliding body 17 by the distance l + L, and the fastener 14 has moved forward by the distance L.

FIG. 4 shows that in the state of FIG. 3, the force of pinching the outer peripheral wall 5 is slightly relaxed, the sliding body 17 is pushed back by the spring 22 by the distance l, and the piston 12a is pushed by the sliding body 17 accordingly. The sliding member 17 is retracted and retracted, and the sliding member 17 retracts to the rear end of the slit 23 and just hits the fastener 14 backwards. Since the fastener 14 and the chuck 13 maintain the fitted state, and therefore the lead 32 is strongly held by the chuck 13 and is prevented from retreating, the lead retainer 15 fixes the lead 32 that is prevented from retreating. It slides back and thus the core 32 relatively projects from the tip of the core pipe 26 by a length l. Up to this FIG. 4, the wick has advanced from the initial position in FIG. 1 by L + 1 and the wick pipe has advanced by L + 1-L by L. Therefore, the tip of the core 32 projects from the tip of the core pipe 26 by l.

In FIG. 5, the force of pinching the outer peripheral wall 5 is completely loosened, the sliding body 17 is pushed back to the same end position as the beginning by the force of the spring 22, and the fastener 14 is retracted by the force of the spring 22 to cause the chuck 13 to move. And the fastener 14 are disengaged and released.
Shows the state when the vehicle has moved backward from the position shown in FIG. 4 by the distance L. The wick 32 is L + 1-L at a position advanced by 1 from the position shown in FIG. 1, and the wick pipe 26 is returned to the original position by LL and is completely housed in the main body. 26
Although it projects a distance l from, it is housed in the main body. This is the storage state in this embodiment. When the fastener 14 is released from the chuck 13 after the fitting with the chuck 13 is released, when the chuck 13 is opened by the self-expanding force, the fastener 14 is repelled by the chuck 13 and is further moved by a distance 1 from the position shown in the figure. Go backwards, but immediately slit 23
It returns to the position where the rear end hits the foot 21 of the sliding body 17 by its own weight and becomes the state of FIG. In this state, the pinching of the lead is completely released, so if the tip of the lead is pushed out of the tip of the mouthpiece, you can easily push it into the mouthpiece and break the lead when dropping the mechanical pencil. It can be prevented.

FIG. 6 shows that in the state shown in FIG. 5, the outer peripheral wall 5 is strongly pressed and the piston 12a is advanced by L + 1 to move the lead pipe 26 and the lead 32 to L +.
The state is shown in which the fastener 14 is moved forward by L and moved to the center holding state. The core pipe 26 projects from the tip of the base 2 by L, and the core 32 projects further from the tip of the core pipe 26 by 1 and this state is a state in which writing by the core 32 is possible.

When writing with a mechanical pencil in this state and the tip of the lead 32 becomes worn and becomes short, temporarily loosen the force of pinching the outer peripheral wall 5 and retreat only the lead pipe 26 by a distance of 1 again. As soon as the outer peripheral wall 5 is pinched, the state shown in FIG. 6 is restored. You may loosen the pinching force completely and pinch it again.

According to the first embodiment described above, the fluid pressure mechanism of the present invention
It has a function of automatically pulling in and out of the internal structure including the core pipe and core case in addition to the functions of holding the core, extending the core, and releasing the core, so it can be inserted into the chest pocket or thrown when not in use or when carrying it. Occasionally, the wick pipe is already stowed, so it won't break pockets or get dirty with the wick.

FIG. 7 shows that among the three members, the chuck, the fastener, and the lead holder, which are pushed by the axial moving means and move in the axial direction, the lead holder does not move, and the chuck and the fastener do not move. It shows a second embodiment in which the lead holder 15 is moved in the direction, and the lead holder 15 is press-fitted near the front end of the mouthpiece 2. The chuck 13 is always biased forward by the spring 33, but the lead case
The abutting of the shaft joint 3 on the shaft joint 18 prevents further advancement. The chuck 13 may be brought into contact with the stepped portion in the base 2 or the lead holder 15 without separately blocking the advance of the chuck 13 by the spring 33. Not only does this cause no trouble, but since the chuck can be brought to the most advanced position in the main body, there is an advantage that the length of the unusable core (so-called core loss) can be reduced.
In this embodiment, a ring piston 12b is used as an axial moving means instead of the piston 12a in the first embodiment.
Is used. By making the piston a ring,
Since the pressure receiving area that receives the fluid pressure increases, both pistons
When comparing 12a and 12a, when the ring piston 12b is used for displacing in the same axial direction, the force of pinching the outer peripheral wall 5 is smaller.

FIG. 8 is an enlarged view of an essential part of FIG. 7 showing the joint 3, the piston 12b, and the outer peripheral wall 5 unitized so that the assembly can be facilitated.
The other part is shown by a one-dot chain line. Reference numeral 34 denotes one to three rods (three in the figure) for transmitting a force between the piston 12b and the core guide 35 at the front end of the core case 18.

The operation of this embodiment will be described. When the knob portion (outer wall 5 of the fluid chamber 6) is pinched for writing from the state of non-use of FIG. 7, the fluid pushes the piston 12b and the rod 34
Retract with. The core case 18 and the core guide 35 are rods.
Since it is pushed by 34 and retracts, the chuck 13 connected to the lead case 18 also retracts. At this time, the chuck 13 that has expanded to release the nipping of the lead retracts with the fastener 14 open for a short slidable distance of the fastener 14, but the lead 32 is held by the lead holder 15. It does not retreat because it is done. Therefore, the core 32 is paid out by the length of a fixed length in which the chuck 13 is opened and retracted.

When the knob force is further applied to the knob, the fastener 14 will
Since it hits the step inside the front part of and is prevented from retreating,
The chuck 13, which is still trying to retract, fits into the fastener 14 and holds the core 32. Write in this state.

If the core protruding from the tip of the core pipe 26 becomes worn, loosen the knob force and the force of the spring 33 will move the core case 18 to the rod.
34 is pushed back and moved forward, the chuck 13 also fits with the fastener 14 and moves forward while holding the core 32, but the fastener 14 immediately hits the stepped portion in the base 2 and is prevented from moving forward. 13
Comes out of the fastener 14 and expands to release the holding of the core 32. In the meantime, the lead extended to the length for which the chuck advances while holding the lead is projected from the tip of the lead pipe. Then, when the knob force is applied to the knob portion again, as described above, the core 32
Is held. There you can write again.

In this way, when drawing out the lead while writing, do not change the position of the fingers or the position of the lead pipe while holding the knob part, just add the knob force to the knob part or remove the knob force. You can continue writing with great convenience.

When writing is finished, the core is not chucked because the knob is not pinched, so it prevents core breakage due to impact when not in use, and protects the core pipe and core as they are built in the mouthpiece. And avoid damage. Also, the core protruding from the tip of the mouthpiece can be easily pulled in if pushed.

The second embodiment has a small number of parts and can be manufactured at low cost, and since the chuck can be brought to the position closest to the tip of the die, the length in which the core cannot be used (so-called core loss) is reduced. can do.

FIG. 9 shows an outer peripheral wall 5 and a fluid chamber 6 as one bag so as to be integrally provided with an axially expandable and contractible one or more (three in the figure) pipes as axial moving means. Elastic body
FIG. 10 is a perspective view showing another embodiment formed by 36a, and FIG. 10 is a cross-sectional view showing a unit formed by incorporating this into the joint 3. In this embodiment, as the axial moving means for axially displacing when the outer peripheral wall 5 is pressed, a piston or the like is not used and the front or rear of the rubber bag 37 forming the fluid chamber 6 having the through hole in the center thereof. Is formed on the side surface of the rubber bag 37 so as to be thinner than the rubber bag 37 or formed into a bellows shape so as to be easily deformed in the axial direction. The small tubular protrusions 39 communicate with the fluid chamber 6. This small tubular protrusion
The rod 34 may be fitted into the 39.

According to this embodiment, there is no fluid leakage, the number of parts is reduced, and the assembly is simplified, so that the manufacturing cost can be reduced.

FIG. 11 and FIG. 12 show the protrusion shown in FIG. 9 and FIG.
A bag-shaped elastic body 36a made of a rubber bag 37 having a side surface 39.
Instead of the small tubular protrusion 39, a bag-shaped elastic body 36b having a large pressure receiving area is shown as an annular small-diameter protrusion 40, and the annular protrusion 40 serves as an axial moving means. Also,
A ring may be fitted to the annular protrusion 40.

When such bag-like elastic bodies 36a and 36b are used, when they are held and pressed by, for example, three fingers, the part of the bag-like elastic body located between the fingers swells without being pressed. If there is a fear, as shown in Fig. 13, use a thick material to form a bag-shaped elastic body 36c.
If a plurality of vertical grooves 41 are provided on the outer circumference of the groove, the bulge between fingers can be prevented. Alternatively, it is conceivable to cover the bulge preventing member 42 shown in FIG. 14 with the bag-shaped elastic body shown in FIG.

The mechanical pencils shown as the above-mentioned first and second embodiments are mainly considered for desktop use, but when these are inserted into the chest pockets and the passengers are on a crowded train, the chest is pressed by another person. Each time the core pipe or core is extended (the core is not held when not in use, it returns easily even if it comes out of the core pipe once, but the core is gradually extended), and the pocket is broken or soiled. There is a risk of This fear can be
It is solved by putting 43 on the front part of the main body.
The gap 44 may be large enough.

Although some embodiments have been described above, the present invention is not limited to these embodiments.

For example, in addition to the above, the original form of a knob type mechanical pencil is used to hold and release the lead and to extend the lead by the relative movements of the chuck, the fastener, and the lead holder. There is a first one disclosed in Japanese Patent Laid-Open No. 145735/53, in which when the pressing member is pressed, the fastener first advances and the chuck and the fastener are fitted to each other, and the pressing force is further increased. When the member is pressed, the tightening tool and the chuck in the fitted state move forward together with the lead, and the lead passes through the lead holder of the lead holder called a slider at the most advanced position due to its own weight and the lead is removed. It is fed out to loosen the force that presses the pressing member and retracts the chuck and the fastener together with the core, and further loosens the pressing force to release the fitting between the chuck and the fastener, and remove it, and the lead holding body when released. With its own weight So please are those that were to feed the core. In this, the fastener is always biased in the backward direction.

Further, although the above-mentioned knob portion is shown as being formed of an elastic material so as to extend over the entire circumference, as shown in FIGS. 16 and 17, the three holding plates 46 are made of an inelastic material to form a fluid chamber. The working (active side) piston 45, which is arranged outside the outer peripheral wall 5a of the nozzle 6 and contacts the fluid in the fluid chamber 6, may be provided inside the pressing plate 46. Also, although only the outer peripheral wall of the fluid chamber is displaced and deformed in the radial direction, the knob portion that is displaced in the radial direction is acted on a member that is displaced in the axial direction by a well-known mechanism such as a cam or a link, and the Alternatively, the fluid chamber may be displaced to reduce its volume.

The fluid is not limited to an organic liquid such as oil, may be an inorganic liquid such as silicon, may be a semi-fluid such as a gel or a sol, or may be a fluid such as a fine particle, without being limited to a complete fluid. Anyway, anything that moves in the axial direction when a knob force in the radial direction is applied to the knob portion may be used. The spring is not limited to the compression coil spring, but may be a tension spring, a leaf spring, or a magnet.

A piston ring or a rubber ring may be used to prevent fluid leakage.

The deformable material for forming the knob portion is not limited to an elastic material such as rubber, but a flexible material such as fibrous material or soft resin may be used. Further, the surface of the knob portion may be provided with a slip groove such as a groove or dimple.

(Effect) In the present invention, a knob force is applied to the knob portion to displace the knob portion in the radial direction and the radial displacement force of the knob portion is transmitted to the axial moving means, and the force transmitting medium by the axial moving means is transmitted. Since the fluid is used as the fluid, the direction of the force can be freely converted, and the volume change of one part of the fluid chamber can cause the volume change of the other part. Therefore, when the cam mechanism is used, The restriction on the length of the cam surface or the cam line, the inclination angle, the length of the link when using the link mechanism, the angle, etc. is released at once.

Moreover, the fluid used as a force transmission medium is placed in the knob part on the outer circumference of the part that is pinched by the finger when writing on the main body, and it is displaceable and deformable in the radial direction to transmit the fluid pressure to one side in the axial direction. Since the annular fluid chamber having holes is filled so as not to leak, when a knob force is applied to the knob portion, the knob portion is axially displaced and deformed to increase the fluid pressure in the fluid chamber. Since the fluid chamber is formed in an annular shape in the knob part and is formed to be shorter in the radial direction than the axial direction, when a knob force is applied to the knob part, it is equivalent to the volume change in the radial direction of the fluid in the fluid chamber. When the portion tries to move in the axial direction, it has an effect of efficiently operating the moving means in the axial direction through a through hole provided on one side in the axial direction, and through the axial moving means, a chuck, a fastener, Fewer lead feeding mechanisms including the three lead holders Also actuating efficiently chuck and clamp in the axial direction.

By such efficient operation in the axial direction, it is possible to obtain a large stroke of the axial moving means even if the knob portion is slightly displaced in the radial direction.

As described above, since a large axial movement can be achieved in the axial moving means by a small radial displacement of the knob portion,
The sharp pencil according to the present invention can be provided with an outer diameter and an appearance that are substantially the same as those of a conventional writing instrument. Moreover, the effect that the knob type sharp pencil has in principle is not lost at all.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of a mechanical pencil according to the present invention, FIGS. 2 to 6 are side sectional views showing the operating states of the above embodiment in the order of operation, and FIG. A side sectional view showing a second embodiment of such a mechanical pencil, FIG. 8 is a side sectional view showing an enlarged main part of FIG. 7, and FIGS. 9, 11 and 13 show a bag-shaped elastic body. A perspective view or a front sectional view showing a different embodiment, FIGS. 10 and 12 are side sectional views showing a unit incorporating the bag-shaped elastic bodies of FIGS. 9 and 11, respectively, and FIG. 15 is a side sectional view of a main part showing a state in which a mechanical pencil according to the present invention is covered with a cap, and FIGS. 16 and 17 show another embodiment of a holding member. It is a side sectional view and a left side view. 1 ... Shaft, 2 ... Clasp, 3 ... Joint, 5 ... Outer wall, 6
...... Fluid chamber, 12a ...... Piston, 12b ...... Ring piston, 13 ...... Chuck, 14 ...... Tightener, 15 ...... Core holder,
17 …… Sliding body, 22 …… Spring, 32 …… Core, 33 …… Spring, 36a, 36b, 36c …… Bag-shaped elastic body, 39,40 …… Projection part, 46 …… Presser plate.

Claims (4)

[Claims] 1. A chuck and a fastener are provided at a front portion of a main body for axially moving and engaging with each other to hold and release a lead, and the lead is always held in front of the chuck with a certain amount of force. A core holder is arranged, and these core holders, chucks,
In a mechanical pencil having a lead-out mechanism including the three of the fasteners, a knob portion is provided on the outer periphery of the portion to be pinched with a finger when writing on the main body, and the knob portion is radially deformable and deformable on one side in the axial direction. An annular fluid chamber having a through hole for transmitting a fluid pressure is arranged, the fluid chamber is filled so that the fluid does not leak, and an axial moving means is continuously provided through the through hole. , The axial moving means is interlocked with the lead-out mechanism, and when a knob force is applied to the knob portion, the fluid chamber is displaced and deformed in the radial direction and at least the chuck of the lead-out mechanism is moved through the axial moving means. A mechanical pencil having a fluid pressure mechanism characterized in that the fastener is actuated in the axial direction, and the knob force is restored when loosened or pulled out. 2. A mechanical pencil having a fluid pressure mechanism according to claim 1, wherein said knob portion is formed of an elastic member such as rubber or plastic or an outer peripheral wall of a fluid chamber made of a flexible member. 3. A mechanical pencil having a fluid pressure mechanism according to claim 1, wherein the axial moving means is composed of a piston. 4. One or a plurality of projecting portions in which the axial moving means communicates internally with a fluid chamber formed by a part of a bag-shaped elastic body made of an elastic member such as rubber or fiber. A mechanical pencil having a fluid pressure mechanism according to claim 1, wherein the mechanical pencil comprises: