JPS6322999B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a writing instrument whose lead can be easily fed out without the need to change hands while writing.

Conventionally, sharp pencils generally have a knob operating part protruding from the rear end of the main body, and the lead can be drawn out in a knock-style manner by finger operation, but it is said that it is necessary to change the grip of the sharp pencil each time when drawing out the lead. It was inconvenient. In addition, recently, as the lead wears out during writing, when the lead protection tube into which the lead is inserted moves back a certain amount, the lead protection tube is pushed back to its original position with the lead, so that the lead is automatically fed out. Something like this is also being developed. However, if the core is simply fed out with the core and the core protection tube flush, it is not possible to make the core protrude by the desired amount from the core protection tube, and the user's requirements are not fully satisfied. However, other conventional structures that automatically feed out the lead have had various problems, such as the feeding operation being uncertain and the structure being extremely complicated.

In view of these circumstances, the present invention, when the lead wears out during writing, presses the tip against the writing surface with writing pressure or a slightly stronger force while holding the main body in the writing position, and then releases the rear pressing force. As long as this is done, the lead can be easily fed out without requiring a knob operation, and the user can make the lead protrude by the desired amount by applying force. It is an object of the present invention to provide a writing instrument that operates reliably and has a relatively simple structure.

That is, the writing instrument of the present invention includes, within the writing instrument main body,
A middle frame equipped with a chuck mechanism that grips the lead to allow the lead to move forward, and a lead protection tube equipped with a lead holding part that holds the lead with a moderate frictional force are arranged. When a pushing force is applied to the core, the core and the chuck mechanism are made to move back together with the core and the chuck mechanism so that it can slide back and forth while being biased forward, and the core protection tube can be slid back and forth while being biased forward. At the same time, the rear part is inserted into the inner frame, a tapered surface is formed on the outer periphery of the rear part of the lead protection tube, and the diameter becomes larger toward the rear, and a trochanter is provided in the middle frame, which contacts the tapered surface and the inner surface of the writing instrument body. The trochanter is held so as to be able to swing inward and outward in the radial direction, and a predetermined portion of the inner surface of the writing instrument body has a slope that approaches the radial center of the writing instrument body at least toward the rear, so that as the trochanter moves back and forth, the trochanter moves in the radial direction of the writing instrument body. forming a swing guide section that swings to
Due to the tapered surface, trochanter and swing guide part,
When the trochanter reciprocates passing through the oscillating guide part while being in contact with the tapered surface and the inner surface of the writing instrument main body, the lead protection tube is moved in the front-back direction relative to the inner frame due to the oscillation of the trochanter. It consists of a mechanism that allows it to slide.

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

FIG. 1 shows the overall structure of the writing instrument of the present invention. In the figure, 1 is a writing instrument main body, which is formed into a substantially cylindrical shape and has a head 2 having a conical outer shape at the tip.
Reference numeral 3 denotes a middle frame placed inside the main body 1, which is formed into a hollow cylinder shape and is equipped to be slidable over a certain range in the front and back.
It is biased forward by a main return spring 5 that is compressed between. A chuck mechanism 6 is provided at the rear of the middle frame 3 to allow the core to advance but prevent it from retreating. The chuck mechanism 6 includes a chuck tube 7 having a chuck portion 8 that can be expanded and contracted, such as split into two, at the tip of a small-diameter cylindrical portion through which the core A can be inserted, and an appropriate number of balls 9 held on the outer periphery of the chuck portion 8. . A chuck spring 12 is interposed between the front inner edge of the receiving member 10 and the rear end edge of the chuck tube 7.
The ball 9,9 is in contact with the ball. In this way, against the force in the direction in which the core A inserted into the chuck tube 7 retreats, the balls 9, 9 are removed from the tapered surface 11.
The core A is strongly gripped by the force applied to the core A, and almost no gripping force is applied to the force in the direction in which the core A moves forward. With this chuck mechanism 6 built into the middle frame 3, the chuck receiving member 10 is elastically pressed rearward by a spring 17 which urges a core protection tube 15 forward, which will be described later. A stopper 13 for the chuck receiving member 10 is provided at the rear end of the frame 3.
By providing this, the chuck mechanism 6 is held at the rear of the middle frame 3. Further, a stopper 14 for determining the maximum retreat position of the middle frame 3 is protruded from a predetermined location on the inner surface of the writing instrument main body 1.

Reference numeral 15 denotes a lead protection tube disposed at the tip inside the writing instrument body 1, which is formed into a pipe shape into which the lead A can be inserted, and has an end member 16 fixed to its rear end, and the tip is connected to the head of the main body. A spring 1 is provided so as to be slidable back and forth in a state of protruding from the spring 1, and is interposed between the rear end of the end member 16 and the chuck receiving member 10.
It is urged forward by 7. The core protection tube 15
A lead holding portion 18 is provided on the inner surface of the lead holding portion 18 for holding the lead A with an appropriate frictional force. In the illustrated example, the lead holding part 18 is formed by fixing a rubber ring to the inner surface of the end member 16, but the position and means for forming the lead holding part 18 on the inner surface of the lead protection layer 15 are different from this example. However, the core holding portion may be formed by, for example, providing a rubber lining to the inner surface of the tip end of the core protection layer 15.

The rear part of the lead protection tube 15 is inserted into the front part of the middle frame 3, and between the rear part of the lead protection tube 15, the front part of the middle frame 3, and the inner surface of the writing instrument main body 1, the lead tip side A mechanism is provided for sliding the core protection tube 15 relative to the middle frame 3 in the front-rear direction so as to perform a core feeding operation in response to pressurization and release of the pressure. As shown in FIGS. 1 and 2, this mechanism consists of a tapered surface 20 formed on the rear outer peripheral surface of the core protection tube 15, and balls 21, 21 as trochanters held at the front of the middle frame 3. and a swing guide portion 22 of the balls 21, 21 formed on the inner peripheral surface of the writing instrument main body 1,
It consists of 22. That is, the core protection tube 15 has a tapered surface 20 formed on the outer peripheral surface of the rear end member 16, the diameter of which increases toward the rear. Middle frame 3
The front part of is located in the hollow part 23 formed in the main body head 2, and the front part of the inner frame 3 is located at one place or at several places (two places in the example) at appropriate intervals in the circumferential direction. Ball holding holes 24, 24 are formed, and balls 21, 21 are held in the respective ball holding holes 24, 24 so as to be able to swing in and out in the radial direction. Instead of the balls 21, 21, trochanters having other suitable shapes such as short cylindrical shapes may be used. These balls 21, 21
is in contact with the tapered surface 20 and the inner circumferential surface of the main body 1 in the hollow portion 23 on its inside and outside. Further, on the inner circumferential surface of the main body 1 in the hollow portion 23, a swing guide portion 2 is provided that swings the balls 21, 21 in and out in the radial direction as the balls 21 move in the front and rear directions.
2 and 22, and in this embodiment, when the middle frame 3 moves halfway through its forward and backward movable range, each ball 2
At locations corresponding to positions 1 and 21, concave swing guide portions 22 and 22 are formed such that the rear half thereof becomes a slope that approaches the radial center of the writing instrument body 1 as the rearward portion approaches. The inner circumferential surface of the main body 1 in the hollow portion 23 except for the locations where the swing guide portions 22, 22 are formed has a constant diameter over a predetermined range from front to back.

Furthermore, in the embodiment, a knob operation mechanism is also provided for convenient removal of the lead A from the lead storage tube 4. That is, the lead storage tube 4 is made to be able to slide back and forth while being biased rearward by the main return spring 5, and a knob operation cap 25 is attached to the rear end of the lead storage tube 4. An appropriate number of partially protruding protrusions 2 for pushing the chuck receiving member are provided on the outer periphery of the intermediate portion of the core guide tube 26 connected to the front end of the core guide tube 26.
7 and 27 are provided. On the other hand, the protruding portion 2 is attached to the inner surface of the elastic portions 28, 28 provided at the rear end of the chuck receiving member 10 and capable of tilting inward and outward in the radial direction.
7 and 27 are provided with pressed protrusions 29 and 29, respectively. These protrusions 27, 27 and 29, 29
This means that the corresponding surfaces are formed with an appropriate inclination or roundness, so that when the lead storage tube 4 moves forward to a certain extent, they come into contact with each other, and when the chuck receiving member 10 moves forward a predetermined distance, the spring 17 against the member 10 is compressed. When pressed from the front and rear directions with a force corresponding to the resiliency of the spring 17 when the springs 17 are pressed against each other, they are designed to overcome each other.

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

The main return spring 5 that biases the middle frame 3 forward has a resilient force that is weaker than normal pen pressure when not compressed, and the ball 21 held by the middle frame 3 moves toward the ball swing guide section 22. It is set in advance so that the resistance force when trying to overcome this after falling down is set in advance to be stronger than normal pen pressure, and the lead holding part 1 of the lead protection tube 15 is
It is desirable that the lead holding force by 8 be made weaker than the elastic force of the spring 17 that urges the lead protection tube 15 forward. A possible core feeding operation will be explained with reference to FIGS. 3 to 8.

Assuming that the lead A has already been taken out from the lead storage tube 4 and is protruding from the lead protection tube 15, the lead A is gripped by the chuck mechanism 6 in response to writing pressure during writing work. In this case, the pen pressure applied to the tip of the lead A is applied to the inner frame 3 via the chuck mechanism 6.
As a result, as shown in FIG. 3, the middle frame 3 moves back together with the core A, and the ball 2
1, the core protection tube 15 moves backward in conjunction with the middle frame 3. When the middle frame 3 moves back by a predetermined amount, the balls 21 move against the rocker provided on the inner peripheral surface of the main body 1, as shown in FIG. It falls into the moving guide portion 22, and the middle frame 3 stops at this position with normal writing pressure. At this time, ball 2
1 shifts the contact position of the tapered surface 20 with respect to the ball 21, and the biasing action of the spring 17 causes the core protection tube 15 to move forward relative to the middle frame 3. However, at this time, since pen pressure is applied to the lead A and a constant positional relationship with the inner frame 3 is maintained, only the lead protection tube 15 moves relatively, and when the pen pressure is released, it is reversed to the pressure applied. Follow the process and return to the original state. Normal writing work is performed in the state shown in FIG. 4, and in this state, the lead protection tube 15 covers the lead A due to relative movement, but as the lead A wears during writing, the lead protection tube 15 may retreat. , written work is possible.

Next, if the user wishes to make the lead A protrude further than in the above state, the tip of the lead A should be protruded with a force somewhat greater than the normal writing pressure while holding the main body 1 in the writing position. Press it against the writing surface. Thus, the above-mentioned figures 3 and 4
After going through the process shown in the figure, the middle frame 3 is further retreated as shown in FIG. 5, and if the pressing force is strong enough, the ball 21 can overcome the swing guide part 22. At this time, as the ball 21 passes through the slope of the rear half of the swing guide section 22, the ball 21 changes from the state shown in FIG.
swings inward, and along with this, the tapered surface 20
As the contact position with respect to the ball 21 shifts, the core protection tube 15 moves rearward relative to the middle frame 3, and the relative positional relationship between the core protection tube 15, the middle frame 3, and the core A remains in its original state. Return to After that, core A
When the pressure applied to the tip of the inner frame 3 and the core protection tube 15 are released, the restoring forces of the springs 5 and 17 move the inner frame 3 and the core protection tube 15 forward to their original positions. In this case, as in the outward journey, while the middle frame 3 is moving, the ball 21 as shown in FIG.
falls into the swing guide part 22 and swings outward, and the core protection tube 15 moves forward by a fixed length l relative to the middle frame 3. Since no pressure is applied to the tip and the chuck mechanism 6 allows the lead A to move forward, the lead A moves forward together with the lead protection tube 15 due to the frictional force of the lead holder 18. That is, the core A also moves forward relative to the middle frame 3. Furthermore, when the ball 21 climbs over the ball swing guide section 22,
As shown in FIG. 7, the core protection tube 15 moves rearward relative to the middle frame 3, and at this time, the core A is prevented from retreating by the chuck mechanism 6.
The core A protrudes relatively to the core protection tube 15. As a result, as shown in Fig. 8, the core protection tube 1 becomes smaller during the return journey compared to before pressurization.
The length l corresponding to the relative movement with respect to the middle frame 3 of 5
As a result, the core A is fed out.

The above-mentioned core feeding operation is performed when a sufficiently large pressing force is applied from the core tip side so that the ball 21 completely overcomes the swing guide part 22 when the inner frame 3 retreats. If it is weaker than normal pen pressure but stronger than normal pen pressure, the forward stroke (when retracting middle frame 3)
When the ball 21 rides halfway up the inclined part between the most recessed part and the terminal end of the swing guide part 22, the pressing force and the resistance force against it are balanced and the ball 21 stops, and the ball 21 stops at the stop position. is determined depending on the applied force. Then, in the return process when the pressing force is released, the center A is adjusted by the distance from the recessedmost part of the swing guide part 22 to the above-mentioned ball stop position.
will be delivered. Therefore, by adjusting the strength of the force with which the leading end of the lead is pressed against the writing surface, etc., the amount of lead feeding can be adjusted at will.

As is clear from such an action, the slope of the swinging guide section 22, particularly in the rear half, which approaches the center of the writing instrument main body as it goes further back, substantially contributes to the lead feeding operation. In other words, when the ball 21 passes through this slope when retreating due to a pushing force, the core protection tube 15 shifts backward with respect to the core A, while when the ball 21 passes through this slope during return, the core protection tube 15 moves toward the middle frame 3. Since the lead A is relatively moved so as to be pulled out from the chuck mechanism 6, the lead A is fed out.

Further, according to the embodiment described above, the lead A can also be fed out by a knock operation. That is, when the cap 25 at the rear end of the lead storage cylinder 4 is knocked and the lead storage cylinder 4 is moved forward, the protrusions 27 and 29 first come into contact with each other as shown in FIG. By being pushed, the core A is fed out. When the chuck mechanism 6 has moved forward to a certain extent, both the protrusions 27 and 2 are shown in FIG. 9b.
9 climb over each other, the chuck receiving member 10 retreats, and only the chuck tube 7 is pushed by the tip of the core guide tube 26, thereby releasing the chuck state. When the core storage tube 4 and the chuck tube 26 return, the core A is released. It will be left in the feeding position. In addition, when taking out the lead A from the lead storage tube 4, especially at the beginning of use, turn the tip of the writing instrument body 1 downward and operate the knob to release the chuck as shown in FIG. 9b above. , the core A is exposed to the core protection tube 1 due to its own weight.
The lead A can be easily protruded from the lead protection tube 15 by sliding down to the vicinity of the lead holding part 18 of No. Can be done. moreover,
Even when the core A can be retracted as desired, it is sufficient to release the chuck by operating the knob and push the core A in from the tip.

Note that the specific structure of the writing instrument of the present invention is not limited to the above-mentioned embodiments, and can be variously modified as illustrated below.

That is, in the embodiment described above, the swinging guide part 22 has a concave shape, but if the swinging guide part has a slope that approaches the center of the writing instrument body toward the rear as described above, the core will move in accordance with the reciprocating movement of the middle frame 3. , the swing guide portion may be formed in a convex shape having the above-mentioned slope in the front half, or in a shape having a plurality of concave and convex portions in the front and rear of a mountain or a waveform. Further, the knob operation mechanism does not necessarily have to have a lead feeding action, and the protrusions 27 and 29 can be omitted and the lead gripping state of the chuck mechanism 6 can be released simply by the knob operation. Core storage tube 4
It can be used when leading out the lead A from a blank or when retracting the lead. In addition, the mechanism known for the conventional knock-type mechanical pencil can be applied as the knob operation mechanism. The chuck mechanism 6 is not limited to the embodiment described above, and a ball chuck or the like may also be adopted.

Furthermore, as another embodiment of the writing instrument of the present invention, the first
Structures as shown in FIGS. 0 to 12 may also be adopted. That is, in this embodiment as well, the writing instrument main body 101 includes an inner frame 103 equipped with a chuck mechanism 106 and a lead protection tube 11 equipped with a lead holding part 118.
5 are the main return spring 105 and spring 1, respectively.
The core protection tube 115 is housed so as to be slid forward and backward while being biased forward by the inner frame 10
forming a tapered surface 120 on the outer periphery of the end member 116 inserted into the protective tube 115 and fixed to the rear end of the protective tube 115;
This embodiment is similar to the basic embodiment in that the balls 121, 121 are held in the ball holding holes 124, 124 of the middle frame 103 so as to be able to swing in and out in the radial direction. However, in the writing instrument main body 101, the head 102 and the body 101a are connected by a connecting member 101b,
A swing guide portion 122 is formed on the inner circumferential surface of the front end of the portion of the connecting member 101b that is screwed into the inner surface of the head 102, and is made of a front-widening tapered surface that is a slope that approaches the center in the radial direction of the writing instrument toward the rear. 1
21, 121 are brought into contact with the tapered surface of this swing guide portion 122 and the tapered surface 120 of the rear end end member 116 of the core protection tube 115. Above middle frame 1
03 consists of a main part 103a, a ring 103b fitted to the rear end, and a rear end member 103c that abuts the ring 103b, and the front end of the middle frame main part 103a protrudes forward from the main body head 102, A core protection tube 11 is further forward from this middle frame main portion 103a.
5 stands out. In this way, the middle frame 103 may be placed within the writing instrument main body 101 with a portion thereof protruding from the writing instrument main body 101.

Further, the chuck mechanism 106 includes a chuck tube 107 having an expandable and retractable chuck portion 108 at its tip, and an appropriate number of balls 10 arranged around the outer periphery of the chuck portion 108, almost the same as in the basic embodiment.
9, chuck receiving member 110, and chuck spring 1
12, and is configured to allow the core to move forward but prevent it from retreating, and is held by the middle frame 103.

On the other hand, as a knob operation mechanism, a lead storage cylinder 104 has a knob operation part (not shown) attached to the rear end;
The core guide member 126 attached to the front end of the core storage cylinder 104 is made to be able to slide back and forth within a certain range while being biased rearward by the main return spring 105.
A cylindrical portion 126a is provided at the front end of the core guide member 126 and is externally fitted onto the rear end of the chuck receiving member 110 with an appropriate frictional force. The rear end of the chuck tube 107 protrudes rearward from the rear end of the chuck receiving member 110 and faces the intermediate step portion 126b of the core guide member 126. When the knob is operated, the core guide member 126 advances the entire chuck mechanism 106 to a certain position, and then moves forward while sliding against the chuck receiving member 110 to push the chuck tube 107 forward. The grip state is released.

In the case of this embodiment, the core feeding operation in response to pressurization and release of pressure from the tip end side of the core is as shown in FIGS. 11 and 12. That is, core A
When a certain amount of pressure is applied to the tip of the chuck mechanism 106 and the middle frame 103 to move back while holding the lead, the ball 121 moves toward the swing guide part 1.
By swinging inward along 22, the core protection tube 115 retreats relative to the middle frame 103,
The core A protrudes by a certain amount relative to the core protection tube 115. Next, the pressure is released and the middle frame 10
3 and the chuck mechanism 106 move forward to the original position, the ball 121 swings outward along the swing guide section 122, and the core protection tube 115 moves toward the middle frame 10.
3, the core A moves forward relative to the core protection tube 11.
It is played out in conjunction with 5. That is, in this case as well, the balls 121 swing in and out in the radial direction in response to the reciprocating movement of the middle frame 103, and the core protection tube 115 moves toward the middle frame 103.
By sliding back and forth relative to 3,
This means that the core A is fed out.

As explained above, the writing instrument of the present invention has a lead protector including an inner frame equipped with a chuck mechanism that grips the lead so as to allow the lead to move forward, and a lead holder that holds the lead with a moderate frictional force. The tubes are housed in a state where they are each biased forward and can be slid back and forth, and
a tapered surface provided on the rear outer periphery of the lead protection tube, and a trochanter that is held in the inner frame in contact with the tapered surface and the inner surface of the writing instrument body and is capable of swinging in and out in the radial direction;
With the rocking guide part of the trochanter provided on the inner surface of the main body, the core protective tube moves against the middle frame as the ball swings in and out in the radial direction while the inner frame and core protective tube move back and forth. Since the swing guide part has a slope that approaches the radial center of the writing instrument body at least toward the rear, a certain amount of pressure is applied to the tip of the lead from the writing surface, etc. If the pressing force is subsequently released, the core is drawn out by the relative movement of the core protection tube with respect to the inner frame when the trochanter passes through the slope upon return. Therefore, the lead can be fed out by a desired amount at any time while the main body of the writing instrument is held in the writing position, and the amount of lead out can be adjusted at will by adjusting the pressing force. Moreover, it has a relatively simple structure, operates reliably, has little risk of failure, and has many practical effects.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a partially omitted sectional view of the entire writing instrument, Fig. 2 is an enlarged sectional view of the main part, and Figs. 3 to 8 are automatic FIGS. 9a and 9b are partial sectional views showing the operation of the knob operating mechanism in the order of strokes, and FIG. 10 is an enlarged sectional view of the main parts showing the operation of the lead feeding mechanism in the order of strokes. Cross-sectional view, Figures 11 and 12
The figures are partial cross-sectional views showing the core feeding operation according to the same embodiment. 1,101... Writing instrument body, 3,103... Middle frame, 5,105... Main return spring, 6,106...
Chuck mechanism, 15, 115...Core protection tube, 1
7,117...Spring, 18,118...Core holding part, 20,120...Tapered surface, 21,121
... Ball, 22,122 ... Swing guide section.

Claims (1)

[Claims] 1. In the main body of the writing instrument, an inner frame equipped with a chuck mechanism that grips the lead so as to allow the lead to move forward, and a lead protection tube equipped with a lead holding part that holds the lead with a moderate frictional force, The middle frame can slide back and forth while being biased forward so that it retreats together with the core and chuck mechanism when a pushing force is applied to the core from the tip, and the core protection tube is biased forward. It is made to be able to slide back and forth, and the rear part is inserted into the middle frame, and a tapered surface is formed on the outer periphery of the rear part of the lead protection tube, and the diameter becomes larger toward the rear. A trochanter in contact with the trochanter is held so as to be able to swing in and out in the radial direction, and a predetermined portion of the inner surface of the writing instrument main body has a slope that approaches the radial center of the writing instrument main body at least toward the rear so that the trochanter can be moved in the front-back direction. Accordingly, a swinging guide part is formed to swing in the radial direction of the writing instrument body, and the tapered surface, the trochanter, and the swinging guide part cause the trochanter to contact the tapered surface and the inner surface of the writing instrument body, while the swinging guide part A writing instrument comprising a mechanism for sliding the lead protection tube in the front and rear directions relative to the inner frame as the trochanter swings when reciprocating through the middle frame.