JPS5838320B2 - Automatic lead-feeding writing instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a writing instrument whose lead is automatically drawn out during writing.

Conventionally, mechanical pencils generally have a knock operation part protruding from the rear end of the main body so that the lead can be drawn out in a knock-type manner by operating the finger, but each time the lead is drawn out while writing, the mechanical pencil There was the inconvenience of having to carry a different one.

In addition, recently, as the lead wears out during writing, the sliding tube into which the lead is inserted is pushed back by the writing surface, and when the writing pressure is released or when it moves back a certain amount, the retractable tube returns to its original state with the lead. Some writing instruments have been developed that automatically feed out the lead by pushing it back into position, but conventional writing instruments of this type have drawbacks such as unreliable feeding and complicated structures. Also, if the lead and the tip of the sliding tube are drawn out flush with each other, the sliding tube will always come into contact with the writing surface with a force that tries to restore itself while writing, which will hinder smooth writing. There was a problem.

In view of these circumstances, the present invention has been developed so that even if the lead wears out during writing, the lead can be fed out without the need for a knocking operation, and in particular, the lead can be fed out to a state where it appropriately protrudes from the sliding tube, and the lead can be drawn out smoothly. To provide an automatic lead feeding type writing instrument which allows writing to be performed, has a simple structure, and provides a reliable feeding operation.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a first embodiment of the present invention.

In these figures, 1 is the writing instrument body, 2 is a sliding tube housed in the front part of the writing instrument body 1, and 3 is the writing instrument body 1.
This is a core storage tube for storing spare cores, which is installed in the rear part of the case.

The writing instrument main body 1 has a head 1a having a conical outer shape, a front main body 1b, a rear main body 1c, etc., which are connected by screwing, etc.
It is formed into a substantially cylindrical shape.

The sliding tube 2 also includes a small-diameter pipe-shaped core protection portion 2a that can be inserted into an insertion hole 4 formed in the main body head 1a, and a core protection portion 2a.
An enlarged chamber 2b integrally connected to the rear end, and the enlarged chamber 2b
It consists of a large-diameter cylindrical part 2d, which is larger in diameter than the enlarged chamber 2b, which is connected to the rear of the writing instrument via a step HB2c, and is equipped to be slidable in the axial direction with respect to the writing instrument main body 1, and the tip of the lead protection part 2a. is projected forward from the main body head 1a.

Inside the rear large-diameter cylinder portion 2d of the sliding cylinder 2, there is an inner cylinder 6, a ball holding frame 7 fitted onto the inner cylinder 6, and a number of balls 8 as appropriate. A ball-chuck type chuck mechanism 5 composed of a coil-shaped chuck spring 9 is inserted.

The inner cylinder 6 allows the core A to be inserted therethrough, and has a required number of engagement holes 10 in a predetermined position in the middle thereof to engage the balls 8 so as to be able to swing in and out. On the other hand, the inner surface of the front part of the ball holding frame 7 is formed with a tapered surface 7a that widens toward the tip, and the valley balls 8 are in contact with the tapered surface 7a and engage the engagement holes 10. It faces the inside of the inner cylinder 6 through...

Further, a chuck spring 9 is compressed between the ball holding frame 7 and a flange-like protrusion 6a provided at the rear of the inner cylinder 6.

In this way, this chuck mechanism 5 moves the ball 8 through the tapered surface 7a of the ball holding frame 7 by the elastic force of the chuck spring 90 to the core A inserted into the inner cylinder 6.
When a gripping force is applied to the ball 8 and an external force is applied particularly in a direction in which the core A retreats relatively, the ball 8...
When the ball 8 is pushed by the ball 8, the gripping force increases significantly, and on the other hand, when an external force acts on the core A to move it forward, the ball 8... loosens and almost loses its gripping force, allowing the core A to move forward. It's like this.

Further, the rear part of the inner cylinder 6 protrudes rearward from the large diameter cylinder part 2d of the sliding cylinder 2, and a core guide cylinder 11 fixed to the tip of the core storage cylinder 3 is attached to the rear part of the inner cylinder 6 at a predetermined position. They fit together using frictional force.

A ring 12 facing the rear of the rear brim-like projection 6a of the inner cylinder 6 is fixed to the rear end of the large-diameter cylinder part 2d of the sliding cylinder 2, and the rear end of the ring 12 and the core guide cylinder 11 are connected to each other. A first return spring 13 that springs the sliding tube 2 forward is compressed between the flange-like protrusion 11a and the flange-like projection 11a.

On the other hand, a lead holder 15 made of a material such as rubber that holds the lead A with a moderate frictional force is inserted into the dog expansion chamber 2b placed in the sliding tube 2 so as to be slidable in the axial direction. A core retainer 1 is provided between the rear end surface of the core retainer 15 and the front end of the inner cylinder 6.
A second return spring 20 that springs the spring 5 forward is compressed.

An appropriate number of protrusions 16 are provided on the outer periphery of the rear end of the core holder 15 to protrude outward through the elongated holes 19 provided in the enlarged chamber 2b. , the protrusion 1
6... and a corresponding locking part 17, such as a chevron shape, that can be elastically engaged and detached from a predetermined location on the inner surface of the writing instrument main body 1.
...and 18 are provided.

Both locking portions 17 and 18 are capable of elastically swinging both or one of them in and out. For example, as shown in FIG. 1
6... to form an elastic locking part 17 by utilizing the elasticity of the material, or a predetermined shape is formed on the lead holder 15 as shown in FIG. By fixing the leaf spring 16' to form an elastic locking portion 17, it is possible to elastically ride over the other locking portion 18.

Then, when the lead holder 15 moves back a certain length together with the sliding tube 2 due to pressure from the brush tip side during the automatic lead feeding operation described later, the locking part 17 climbs over the locking part 18 and locks on the rear side thereof. The positional relationship between both the locking portions 17 and 18 is set so that

Moreover, the locking force by both the locking portions 17 and 18 and the second
The relationship between the spring force of the return spring 200 is that when the spring 20 has the same length as the normal state shown in FIG. The setting is such that when the locking force is lifted, the elastic force that increases accordingly is larger than the locking force.

The sliding tube 2, the chuck mechanism 5, the lead holder 15, etc. constitute an automatic lead feeding mechanism, but in this embodiment, the lead A is further guided out from the lead storage cylinder 3 to a state where it can be automatically fed out. The following preliminary operation mechanism is attached so that the preliminary operation can be performed in a knock-type manner.

That is, the lead storage tube 3 is made slidable in the axial direction with respect to the writing instrument body 1, and the knock operation cap 21 that protrudes outward from the writing instrument body 1 is fitted to the rear end of the lead storage tube 3. A chuck release tube 22 is connected to the tip of a core guide tube 11 fixed to the tip of the core storage tube 3.

The chuck release tube 22 is normally located within the inner tube 11 by a certain distance behind the balls 8 so as not to disturb the automatic core feeding operation, and the tip portion 22a is It is formed into a tapered shape.

Further, the lead guide cylinder 11 is fitted into the inner cylinder 6 with a certain frictional force in a state that allows the inner cylinder 6 to retreat during an automatic core feeding event, and this frictional force is applied to the first return Spring 1
It is set to be weaker than the 30 repulsion force and to be suitable for the preliminary operation for lead derivation which will be described later.

At a predetermined location on the inner surface of the writing instrument main body 1, a stopper 23 is provided rearwardly with respect to the lead guide tube 11 and the lead storage tube 3 in correspondence with the brim-like protrusion 11a of the lead guide tube 11.

In addition, the amount of forward movement of the inner cylinder 6 in the preliminary operation for leading out is regulated by the inner surface of the intermediate step 2c of the sliding cylinder 2 and the flange-like protrusion 6b provided near the front end of the inner cylinder 6. Stoppers are formed that face each other in the front and back at a constant interval.

The operation and effect of this writing instrument will be explained next.

In a normal state, as shown in FIG.
30 elastic force, the core guide tube 11 and the core storage tube 3 are held at a position where the flanged protrusion 11a of the core guide tube 11 abuts against the stopper 23, while the front end surface of the expansion chamber 2b The sliding tube 2 is held at a position where it abuts the inner surface stepped portion of the inner tube 1a, and the elastic force of the second return spring 200 holds the core holder 15 at the front end position of the enlarged chamber 2b. The rear collar protrusion 6a of 6 is attached to the ring 1 at the rear end of the sliding tube 2.
The chuck mechanism 5 is held at a position where it abuts the chuck mechanism 2.

Assuming that the lead A has already been led out to the tip of the sliding tube 2, if the lead A is worn out due to writing, the lead A will be automatically extended according to the application and release of pen pressure during writing. It is brought out.

The operation in this case will be explained with reference to FIG. 4. First, when a certain amount of pressure (pen pressure) is applied from the writing surface to the tip of the brush, the chuck mechanism 5 will hold the lead A as shown in FIG. 4a. , the sliding tube 2 and the chuck mechanism 5 move backward against the elastic force of the first return spring 130, and as a result, the core holder 15
also retreats.

When these move back a certain distance, the locking part 17 of the lead holder 15 climbs over the locking part 18 of the writing instrument main body 1 and locks on the rear side thereof.

Next, when the pen pressure is released, as shown in FIG. Until the tube 2 reaches near its original position, the locking state of the locking portions 17 and 18 is maintained, so that only the core holder 15 remains in the retracted position.

At this time, a certain amount of frictional resistance is applied to the lead A by the lead holder 15, but if this frictional resistance acts, the chuck mechanism 5
Since a larger gripping force acts on the lead A, the lead A, while being gripped by the chuck mechanism 5, moves forward to its original position against the frictional force of the lead holder 15.

When the sliding tube 2 reaches near its original position, the second return spring 20 is compressed and its restoring force is applied to the locking portion 1.
By overcoming the locking forces of 7 and 18, the locking portions 17,
18 is detached, and as a result, the core holder 15 returns to its original position later than the sliding tube 2, as shown in FIG. 4C.

At this time, since the gripping force of the lead A by the chuck mechanism 5 is extremely small in the direction in which the lead A moves forward, the lead A is held by the frictional force of the lead holder 15 and moves forward, lagging behind the sliding tube 2. As the holder 15 moves forward, the core A is drawn out.

In this automatic lead feeding mechanism, the strength and feeding amount of the first return spring 13 or the second return spring 200 may be set so that the lead A is fed out in small amounts in proportion to the wear of the lead A. Alternatively, the strength of the spring 13 may be set so that the feeding operation is performed when pressure is applied to a certain degree stronger than normal writing pressure.

According to the latter, it is easy for the user to adjust the feeding amount.

Further, according to this embodiment, a preliminary operation for leading out the lead A from the lead storage tube 3 and setting it in a state where it can be inserted into the sliding tube 2 before use is performed by a knocking operation as shown in FIG.

That is, first, the lead A is removed from the lead storage tube 3 by knocking the rear end cap 21 deeply to the unzipped state shown in FIG. It is led out by its own weight until it reaches the rear end of the holder 15.

Next, when the knock is released from this state and then knocked again, the lead storage cylinder 3 and the lead guide cylinder 1 are opened accordingly.
1 moves forward, but in the first half of this forward movement, as shown in FIG.
1 and moves forward together with the twin-core guide cylinder 11.

Therefore, the chuck mechanism 5 moves forward S while gripping the lead A, and pushes the tip of the lead A into the lead holder 15.

When the inner cylinder 6 moves forward a certain distance, the brim-like protrusion 6b near its tip comes into contact with the intermediate step 2c of the sliding cylinder 2, so that the inner cylinder 6 is stopped and the core storage cylinder 3 and the core are moved forward. The guide tube 11 continues to move forward against the frictional force with the inner tube 6, and as shown in FIG.
. . . and pushes the ball 8 . . . outward to release the chuck state.

If the knocker is removed from this state, the return spring 13,
The lead storage 3, the lead guide tube 11, and the chuck mechanism 5 return to their original positions with an elastic force of 200 mm. At this time, the chuck force of the chuck mechanism 5 does not work on the lead A, so the lead A is attached to the lead holder 15. It is held and left in the position shown in Figure 5b.

Thus, from now on, the lead A can be brought out into a usable state by repeating this knocking operation or by using the automatic lead feeding operation described above.

Further, it is also possible to arbitrarily withdraw the lead A that has been drawn out too much in the unzipped state where the cap 21 is deeply knocked.

6 and 7 show a second embodiment of the present invention. In this embodiment, a portion corresponding to the inner cylinder 6 in the first embodiment is provided integrally with the sliding cylinder 32, simplifying the structure. ing.

That is, in this second embodiment, the sliding tube 32 is divided into a distal end side core protection part 32a, an enlarged chamber 32b for housing the lead holder, and
Small diameter cylindrical portion 32 integrally connected to the rear end of the enlarged chamber 32b
It is composed of c.

A ball holding frame 37 having a tapered inner surface is fitted onto the intermediate portion of the small diameter cylindrical portion 32c, and an appropriate number of balls 38 accommodated in the ball holding frame 37 are inserted into the small diameter cylindrical portion 32c. 32c through the engagement hole 40 provided in the small diameter cylindrical portion 32c, and between the rear end surface of the ball holding frame 37 and the flange-like protrusion 32d provided at the rear of the small diameter cylindrical portion 32c. A chuck mechanism 35 is constructed by compressing a chuck spring 39 into the.

Then, the chuck release tube 52 provided in the core guide tube 41 is fitted into the small diameter tube portion 32c with a predetermined frictional force,
In addition, the flange-like protrusion 32d of the small diameter cylindrical portion 32c and the core guide tube 4
A first return spring 43 is compressed between the first return spring 43 and the rear brim-like protrusion 41a.

On the other hand, the core holder 45, which is slidably installed in the expansion chamber 32b, has elongated holes 49 provided in the expansion chamber 32b at several locations on its outer circumferential surface to allow the outside of the expansion chamber 32b to pass through. Projections 46 protruding in the direction are provided in succession, and the projections 4
6... Elastic locking parts 47..., 48... corresponding to the rear end portion and a predetermined location on the inner surface of the writing instrument main body 1
. . . are provided, and the front end portion 46a of the projection 46 . It is used as a stopper.

Under normal conditions, due to the elastic force of the second return spring 50 compressed between the rear end surface of the core holder 45 and the rear end of the expansion chamber 32b, the protrusion front end 46a of the core holder 45 is 1a
The sliding tube 32 and the core holder 45 are kept in a state in which they are in contact with the stepped protrusion 1d and the front end of the elongated hole 49 is in contact with the protrusion front end 46a, and in this state, the main body head A stopper surface 1e for restricting the forward movement of the sliding tube 32 provided on the inner surface of the slider 1a faces the front surface of the enlarged chamber 32b at a constant distance.

In this case, in order to maintain this state during normal times, the elastic force of the second return spring 500 is made stronger than that of the first return spring 43, and
The sum of the elastic force of the first return spring 430 and the frictional force between the small diameter cylindrical portion 32c and the chuck release tube 52 is equal to the elastic force of the second return spring 430.
By setting it to be larger than 00 bullet force,
A knock-type preliminary operation, which will be described later, becomes possible.

The structure other than these is the same as that of the first embodiment.

Even with the structure shown in this second embodiment, the automatic lead feeding operation in response to application and release of pen pressure is the same as in the first embodiment.

In addition, in the knock type preliminary operation before use,
When the lead storage cylinder 3 and the lead guide cylinder 41 move forward in response to the knock operation, the sliding cylinder 32 and the chuck mechanism 35 move forward together with the lead guide cylinder 41 due to frictional force, and come into contact with the stopper surface 18 and slide. After the movable barrel 32 has stopped, the chuck release tube 52 further moves forward to release the chuck state as shown in FIG.
Core A can be extruded as a preliminary operation using the same principle as in the embodiment.

In addition, in the first and second embodiments described above, the chuck mechanism 5 or 35 does not necessarily need to be provided with the elastic force by the chuck spring 9 or 39, and the ball 8...
. . . or 38 . . . when it tries to roll in contact with core A, the ball guiding action by the tapered surface of the ball holding frame prevents core A from retreating but allows it to move forward. A chuck action can be provided, and therefore, the chuck springs 9 and 39 may be omitted and the ball holding frame may be integrally installed in the inner tube 6 or the small diameter tube portion 32c.

In addition, when a chuck spring is provided, as shown in FIG. 8, when the chuck is released by a knocking operation, the balls 38...
In order to facilitate the movement of opening outward while being pushed forward somewhat by the chuck release tube 52,
A stopper 32f for the ball holding frame 37 may be protrudingly provided on the outer periphery of the small diameter cylindrical portion 32c close to the front end of the ball holding frame 37.

9 and 10 show a third embodiment of the invention.

In this embodiment, inside the rear large diameter cylindrical portion 62d of the sliding tube 62 formed in the same shape as the sliding tube 2 in the first embodiment,
An intermediate cylinder 67 that can slide within a certain range with respect to the sliding cylinder 62, a chuck tube 66 slidably inserted into the intermediate cylinder 67, balls 68, and a chuck spring 69.
A chuck mechanism 6'5 is formed.

The distal end of the chuck tube 66 is provided with a chuck part 66a that can be expanded and contracted, such as a three-split shape, and the inner surface of the intermediate cylinder 67 is formed with a tapered surface 67a, which is adapted to be engaged with the outer periphery of the chuck part 66a. A number of poles 68 .

This chuck mechanism 65 also has a chuck spring 69 under normal conditions.
The tapered surface 67a and the ball 68...
... imparts a certain degree of core chucking force to the chuck part 66a, and in particular, the core A inserted into the chuck tube 66.
When an external force is applied in the direction in which the core A retreats, an inward force acts on the chuck part 66a from the tapered surface 67a, increasing the chuck force.On the other hand, in response to an external force in the direction in which the core A moves forward, the chuck part 66a loosens and the core This allows A to move forward.

Further, the rear part of the intermediate cylinder 67 protrudes to the rear of the sliding cylinder 62, and the rear end is connected to a cylinder frame 6 fixed to the front end of the core storage cylinder 3.
1 with a predetermined frictional force, a contact surface 61a is provided at the inner rear part of the cylinder frame 6'1 and faces the rear end surface of the chuck tube 66 at a constant distance, and the front end of the cylinder frame 61 and the sliding tube A first return spring 73 is provided between the rear end ring 72 of 62 and the rear end ring 72 .

The structures of the core holder 75, the corresponding elastic locking portions 77 and 78, the second return spring 80, etc. are the same as in the first embodiment.

With the structure shown in this embodiment, the operation of automatically feeding out lead A in response to application and release of pen pressure is basically the same as in the first embodiment, and when pen pressure above a certain level is applied, When the sliding tube 62, the chuck mechanism 65, and the lead holder 75 move back together with the lead A and the pen pressure is released, the sliding tube 62 and the chuck mechanism 65 return to the working position while gripping the lead A. However, after this, the lead holder 75 holds the lead A and returns to its original position, so that the lead A is automatically fed out.

In addition, during a preliminary operation for leading out the lead A for use, as the lead storage cylinder 3 and the cylinder frame 61 move forward due to the knocking operation, the cylinder frame 61 is first moved by frictional force as shown in FIG. 10a.
1, the intermediate cylinder 67 moves forward, and therefore the chuck mechanism 65 moves forward while pushing the lead A, and holds the lead A in the lead holder 75.
to rush into.

Further, the stepped portion 67b near the front end of the intermediate cylinder 67 is connected to the sliding cylinder 62.
After the intermediate cylinder 67 comes into contact with the intermediate stage portion 62c and stops,
When the cylinder frame 61 continues to move forward, its contact surface 61a contacts the rear end of the chuck tube 66 and pushes the chuck tube 66 forward, as shown in FIG. 10b, and the balls 68...
. . moves toward the larger diameter side of the tapered surface 67a, the chuck portion 66a expands outward, and the chucked state is released.

After this, when the knocker is removed, the chuck mechanism 65 retreats to its original position while in the unzipped state, and then the cylinder frame 61 further retreats to its original position, thereby returning to the chucked state.

Thus, in this case as well, it is possible to extrude the core A as a preliminary operation.

According to the third embodiment, since the chuck portion 66a of the chuck mechanism 65 grips the lead A in surface contact, the lead A can be gripped reliably and stably during writing, pressurization, etc.

Note that in each of the above embodiments, means for projecting the sliding tube forward;
Spring (first return spring, second return spring) was used as a means to spring the core holder forward, but instead of these springs, a pair of magnets with the same magnetic poles facing each other so as to repel each other were used. You may also use it.

Furthermore, in each of the above embodiments, the small-diameter pipe-shaped core protector 2a or 32a that can be inserted into the insertion hole 4 of the main body head 1a is integrally fixed to the sliding tube 2 or 32, 62.
A core protection pipe corresponding to the core protection part 2a is separated from the sliding tube, and the rear part of the pipe is slidably inserted into the sliding tube, and the rear end is connected to the core holder 15 or 45, By fixing to 75, the core protection pipe may move integrally with the core holder.

The structure of the other parts is not limited to the above embodiments, and the design may be changed as desired without departing from the gist of the present invention.

As explained above, the writing instrument of the present invention has a sliding tube that is slidably installed inside the writing instrument body and is pushed forward by a spring or a magnet, and a core attached to the sliding tube that does not allow forward movement. A chuck mechanism that prevents backward movement, a lead holder that is slidably inserted within a sliding barrel within a certain range and springs forward by a spring or magnet, and provided on the lead holder and the inner surface of the writing instrument body. Due to the corresponding elastically removable stoppers, when pressure is applied to the tip of the brush with the lead inserted into the sliding barrel, the sliding barrel, chuck mechanism, and lead holder move back, and the pressure is released. When this happens, the sliding tube and chuck mechanism return to the working position while holding the lead, and then the lead holder returns to the working position while holding the lead. If the lead wears out while writing, the lead can be automatically fed out by simply applying and releasing pressure, eliminating the need to change the writing instrument and knocking each time while writing.
In addition, the core can be fed out to a desired extent from the tip of the sliding tube, and the feeding operation is reliable, and many other excellent effects are achieved.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, and FIG. 1 is a sectional view of a writing instrument;
FIG. 2 is a perspective view of the lead holder, FIG. 3 is a sectional view showing another example of the lead holder, FIGS. Figures a and b are half-sectional views of the main parts showing the operation of the knock type preliminary operation in the order of strokes, Figure 6 is a sectional view of the main parts of the writing instrument showing the second embodiment, and Figure 7 is the knock type according to the same embodiment. FIG. 8 is a partial sectional view showing a modified example of the chuck mechanism; FIG. 9 is a sectional view of the main part of the writing instrument showing the third embodiment; FIGS. 10 a and b FIG. 2 is a half-sectional view of a main part showing the operation by the knock type preliminary operation in the order of strokes according to the same embodiment. 1... Writing instrument body, 2, 32, 62...
・Sliding tube, 5, 35, 65... Chuck mechanism, 13, 43, 73... First return spring,
15, 45, 75... core holder, 17, 18,
47, 48, 77, 78... elastic locking part, 20
, 50, 80... Second return spring.

Claims (1)

[Claims] 1. A sliding tube capable of sliding within a certain range in the axial direction is equipped at the front part of the writing instrument body, and a core inserted into the sliding tube is inserted into the rear part of the sliding tube and cannot move forward with respect to the sliding tube. A chuck mechanism is installed to grip the core in such a way as to allow it but prevent it from retreating, and the chuck mechanism and sliding tube are springed forward by a spring or magnet, and the core is held within the sliding tube by moderate frictional resistance. The lead holder is inserted into the sliding tube so that it can slide in the axial direction within a certain range while being pushed forward by a spring or a magnet, and the lead holder and the inner circumferential surface of the writing instrument body are placed in a predetermined position. When the core holder retreats with the sliding tube due to pressure applied from the tip side, the two parts lock together, and when the sliding tube returns due to the release of the pressure, the sliding tube reaches near its original position. A corresponding locking part that can be elastically locked and released is provided to maintain the locked state against the elastic force applied to the core holder until the sliding cylinder returns to near its original position when the pressing force is released. An automatic lead feeding type writing instrument characterized in that the lead holder returns to its original state later than the return operation of the sliding barrel when the locked state of both of the locking parts is released.