JPH08282179A - Automatic pencil - Google Patents

Abstract

PURPOSE: To reduce wear of a lead and produce a good writing function by a method wherein frictional resistance at a tip of a slider is decreased in a pipe sliding type automatic pencil. CONSTITUTION: In an automatic pencil wherein lead 16 is held, released, and drawn out by longitudinal motion of a chuck 1 arranged at a head of a shaft cylinder 3, a slider 9 which can be freely retreated as the lead 16 is worn is provided to a tip central hole of a mouthpiece 8 fitted to a tip of the shaft cylinder 3. A plurality of balls 14 are, in a freely rollable manner, embraced via a holder at a tip of the slider 9. A lead-guiding pipe 17 is provided in a central hole formed by contact with respect balls, and the lead 16 can be inserted in the lead-guiding pipe 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a so-called pipe slide type mechanical pencil.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional pipe slide type mechanical pencil. First, the chuck 50 is loosely fitted to the outer periphery of the tip end of the chuck 50, and then inserted into the chuck insertion hole of the shaft cylinder 52 from the rear end side, and the locking portion 56 at the rear end of the chuck 50 has the shaft portion 54 of the core case 53. It is locked in the connecting hole. A spring 57 is stretched between the core case 53 and the shaft cylinder 52, and the fastener 51 contacts the tip of the shaft cylinder 52 to close the chuck 50 and grip the core 67. A base 58 is screwed onto the tip of the shaft cylinder 52, and a slider 59 having a tip pipe 66 is internally mounted on the base 58 so as to be slidable in the axial direction. A connecting hole is provided in the front portion of the slider 59, and the rear portion of the tip pipe 66 is fitted therein. A core insertion hole 65 is provided in the center of the slider 59 at the center of the shaft.
The rear part has three gripping pieces 61 on the circumference of the axis center,
A rubber holding chuck 64 having a core insertion hole having a diameter slightly smaller than the core diameter is gripped by the gripping piece 61, and the gripping piece 6 is held.
The holding chuck 64 is fixed so as not to be pulled out by the engaging portion 62 that is provided so as to project from 1. Further, three pressure contact pieces 63 are provided between the grip piece 61 on the rear portion of the slider 59 and the concentric grip pieces 61, and are in pressure contact with the inner peripheral surface of the base 58. The slider of the mechanical pencil configured as described above can be slid axially on the inner peripheral surface of the die by a pressure contact piece with appropriate frictional resistance and can be stopped at a desired position.

In the conventional pipe slide type mechanical pencil constructed as described above, the tip pipe 66 is retracted while the tip surface of the tip pipe 66 is rubbed against the paper surface as the core wears during writing. The tip surface is provided with appropriate rounded corners to reduce the frictional resistance, but as it is used, it becomes an edge due to wear, the contact surface becomes large and the frictional resistance increases and the writing feeling deteriorates. It leads to the problem of breaking the page.

[0004]

By the way, it is known that a pipe slide type mechanical pencil is excellent as a mechanical pencil that can be written darkly (the core is soft) and the core will not be broken even if a slightly excessive writing pressure is applied. There is. Further, an automatic lead-out type mechanical pencil is also widely known, and a slider which is always urged in front of the mouthpiece by a spring and moves backward as the lead wears is also well-known structure. However, as described above, there is a problem that the writing feeling is bad due to the friction of the tip end surface and the paper surface is broken. The present invention aims to solve the problem of breaking the surface of the paper by reducing the frictional resistance and making the writing feel smoother than the conventional pipe slide type mechanical pencil.

[0005]

[Means for Solving the Problems] In a mechanical pencil configured to grip and release a lead by a back-and-forth movement of a chuck arranged in front of a barrel, and to feed the lead, the mechanical pencil is attached to the tip of the barrel. A slider is provided at the center of the tip of the mouthpiece so that it can move backward with wear of the core, and a plurality of balls are rollably held via a holder at the tip of the slider.
A core guide pipe is provided in a center hole formed by contacting each ball, and the core is configured to be inserted into the core guide pipe, and the slider has a holding chuck for frictionally holding the core at a rear end, A receiving member for restricting the backward movement of the ball is provided on the front side, and the holder is externally mounted while the ball is seated on the receiving member so that the ball cannot be pulled out and is rotatably held.

A mechanical pencil has a structure in which a core fixing chuck is tightened with a ball so that the core has a sufficient gripping force for writing, but a slight force is required to pull out the core from the chuck. A slider having the above-mentioned structure which is constructed so that a core is pulled out from a chuck into a tip center hole of a mouthpiece attached to the tip of a cylinder, is always urged forward by a spring, and is retractable in writing as the core wears. Is provided.

[0007]

EXAMPLES Examples will be described with reference to the drawings.
1 to 3 show a knock type mechanical pencil according to the first embodiment of the present invention, in which a chuck 1 has a chuck insertion hole of a shaft cylinder 3 from a rear end side after a fastener 2 is fitted on an outer peripheral portion of a tip thereof. And the rear end of the chuck 1 (where necessary, a locking portion is formed) is fixed to a connecting hole provided in the shaft portion 6 of the lead case 5.

A spring 7 is provided between the core case 5 and the barrel 3.
Is stretched, and the fastener 2 comes into contact with the tip of the barrel 3 and the chuck 1
Is closed to hold the core 16.

A mouthpiece 8 is screwed on the tip portion of the shaft tube 3, and a slider 9 which is retractable with wear of the core is inserted into a tip center hole of the mouthpiece 8. Incidentally, the slider 9 is usually provided with a pressure contact portion or the like having appropriate frictional resistance with respect to the inner peripheral surface of the mouthpiece 8.

By the way, the slider 9 is provided at its rear end with a shaft portion 10 to which a holding chuck 11 for frictionally holding a core is fixed, and at its front end is provided a receiving member 12 for restricting the backward movement of the ball 14, and the receiving member 12 is provided. A ball receiving seat 12a is appropriately formed on the entire surface of the member 12, and a plurality of balls 14 are seated on the receiving seat, and a holder 13 formed of a metal pipe or the like is externally mounted so that the ball 14 cannot be removed. A crimped portion 15 or the like is formed at the tip so as to be held in a rollable manner. A core guide pipe 17 through which the core 16 can be inserted is fixed to the center of the receiving member.

It is also possible to form the shaft portion 10 from a synthetic resin having excellent elasticity and integrally provide an elastic holding portion capable of holding the core instead of the holding chuck 11. Further, the receiving member 12 is selected from a material having excellent wear resistance and low frictional resistance, but it may be provided integrally with the shaft portion 10 in terms of a structure. The ball 14 is made of stainless steel,
Although cemented carbide, ceramics, hard resin or the like is selected, the inner surface of the ball holding portion of the ball 14 and the holder 13 is subjected to surface treatment such as plating and Teflon in order to make rolling of the ball smoother. It is also possible to apply or impregnate the receiving member 12 with a lubricant.

FIGS. 4 to 7 show an automatic lead-out type mechanical pencil according to a second embodiment of the present invention.
First, an eraser stopper 47 having an eraser 48 attached is fixed to a rear end hole of a core case 28 that appropriately protrudes from the rear end of the shaft cylinder 20, and the knock cover 4 is attached to the outer periphery of the rear end of the core case 28.
6 is detachably fitted. Further, a slit 43 is formed on the rear end side surface of the shaft cylinder 20, and a locking step portion is provided at a predetermined position of the slit 43. Further, a rib-shaped bulging portion 44 having a projection 44a at the front end is provided on the rear side surface of the core case 28, and the projection 44a abuts on the locking step portion of the slit 43 by elastic deformation. The lead case 28 is locked to prevent the lead case 28 from coming out behind the barrel 20.

A shaft portion 29 is provided at the tip of the core case 28, and a projection 30 is formed on the outer periphery of the shaft portion 29. In addition, a slit portion 26 is formed on the rear end side surface of the chuck case 21, which will be described later, and a locking portion 27 is provided on the side surface portion. (Note that the two-dot chain line portion shown in FIG. 4 shows the shape in which the slit portion 26, the locking portion 27, and the protrusion 30 are viewed from the upper surface.) The shaft portion 29 is fitted into the rear end hole of the chuck case 21 and the protrusion 30 and the engaging portion 27 are engaged. or,
The lead case 28 has a collar portion 28b and a step portion 20a of the barrel 20.
The coil spring 31 normally urges the rear part between and.

By the way, a fastening cylinder 25 is fixed to the tip of the chuck case 21. The inner diameter of the front end of the fastening cylinder 25 has a tapered shape, and the core fixing chuck 22 in which the balls 23, 23 'contacting the tapered surface are fitted in the outer surface recesses is internally provided. The coil spring 24 interposed between the stepped portion formed at the rear end and the coil spring 24 pushes it backward. The core fixing chuck 22 is made of a synthetic resin molded product having excellent elasticity and high abrasion resistance, and is constructed by combining two split cylindrical bodies. When the writing pressure acts on the core, the balls 23, 23 'roll and the core fixing chuck 22 is tightened by the wedge effect to grip the core. However, when the core is pulled forward, the spring force of the coil spring 24 is increased. Is set to be weak so that a small force of about several grams is possible. By the way, the chuck case 21 is formed of a resin molded product, and the tightening cylinder 25 is formed of metal. Originally, the chuck case and the tightening cylinder are integrally formed, but the cost is high if they are made of metal because of complicated processing.
If it is made of resin, the durability will be insufficient. The reason why the tightening cylinder 25 is made of metal is that the wear resistance due to rolling of the balls and the rigidity of the tapered portion are taken into consideration. An integral resin molded product may be used if durability is compromised.

A screw portion is formed on the inner diameter portion of the front end of the shaft cylinder 20, and the base 32 is screwed into the screw portion. The base 32 may be press-fitted into the outer diameter portion of the front end of the barrel 20.
A slider 33, which will be described later, is fitted inside the base 32, and a fixture 37 is fixed behind the slider 33, and a coil spring 38 is provided between the rear end of the slider 33 and the fixture 37.
Is provided to constantly urge the slider 33 forward of the base 32. The slider 33 is the coil spring 3
It is possible to retreat against 8. Further, since the spring force of the coil spring 38 may be larger than the force for pulling out the lead from the lead fixing chuck 22, it can be set to about 10 to 20 grams.

By the way, the slider 33 has a shaft portion 34 to the rear end of which a holding chuck 35 for frictionally holding the core is fixed.
Is provided, and a receiving member 39 for restricting the backward movement of the ball 40 is provided in front of the receiving member 39, and a receiving seat 39a is appropriately formed on the entire surface of the receiving member 39, and a plurality of balls 40 are provided on the receiving seat.
A holder 36 formed of a metal pipe or the like in the seated state is exteriorly mounted, and a caulking portion 41 or the like is formed at the tip end so that the ball 40 cannot be pulled out and is rotatably held.
Further, a lead guide pipe 42 through which the lead 16 is inserted is fixed to the center of the receiving member 39. The ball 40 is provided in a slightly protruding shape from the tip of the core guide pipe.

It is also possible to form the shaft portion 34 from a synthetic resin having excellent elasticity and integrally provide an elastic holding portion capable of holding the core instead of the holding chuck 35. Further, a material having excellent wear resistance and low frictional resistance is selected for the receiving member, but it is possible to provide the receiving member integrally with the shaft portion 34 in terms of configuration. Further, the ball 40 is selected from stainless steel, cemented carbide, ceramics, hard resin, etc., but in order to make the rolling of the ball smoother, the inner surface of the ball holding portion of the ball 40 and the holder 36 is plated or has a surface of Teflon or the like. Apply processing.

[0018]

In the pipe slide type mechanical pencil of the first embodiment described above, the ball 14 is in point contact with the paper surface and freely rolls during writing, so that the friction resistance is small and the abrasion is small. Further, since the lead 16 is guided by the lead guide pipe 17, the axialness of the lead is maintained and the core breakage is not eliminated. or,
Since the conventional slider rubs the paper surface with the tip surface circumscribing the core, it may be thicker than the actual drawing line width or the edge of the drawing line may be dirty, but according to the example of the present application, it is separated from the circumscribing part of the core. Since the ball contacts the paper surface, the line width does not change,
Also, there is no stain on the edge of the line.

In the automatic lead-out type mechanical pencil of the second embodiment, when the lead 16 is inserted to the tip of the slider 33, the tip of the slider 33 is applied to the paper surface for writing. Slider 3 as the core is consumed
3 retracts against the coil spring 38. When the tip of the slider 33 is separated from the paper surface, the slider 33 advances by the biasing force of the coil spring 38, and the lead 16 is pulled out from the lead fixing chuck 22 by the frictional force of the holding chuck 35. When the lead is normally extended, the rear end of the knock cover 46 may be knocked, and the shaft portion 29 at the tip of the lead case 28 connected to the knock cover 46 is provided between the flange portion 28b and the step portion 20a of the barrel 20. While compressing the coil spring 31 interposed, the tightening cylinder 25 integrated with the chuck case 21 is moved forward (the projection 30 engages with the locking portion 27 and the shaft portion 2
9 and the chuck case 21 are interlocked with each other). In this state, the chuck case 21 is prevented from moving forward, only the lead case 28 moves forward, the tip of the shaft portion 29 comes into contact with the rear end of the lead fixing chuck 22, the lead fixing chuck 22 is opened, and the lead is fed out. Be seen. Next, when the rear end knock of the knock cover 46 is released, the chuck case 21 is retracted together with the lead case 28 while the lead fixing chuck 22 is kept open with the projection 30 and the engaging portion 27 engaged, and the chuck case 21 is removed. Shaft cylinder 20
When the inner stage 20b is prevented from retreating, only the core case 28, that is, the shaft portion 29 retreats to the original state.

In the mechanical lead-out type mechanical pencil constructed as described above, the ball 40 is in point contact with the paper surface and freely rolls during writing, so that the friction resistance and wear are small. Further, since each ball is substantially circumscribed on the outer periphery of the core 16, the axialness of the core is maintained and the core breakage cannot be eliminated.
In addition, since the conventional slider rubs the paper surface with the tip surface circumscribing the core, it may be thicker than the actual line width or the edge of the line may be dirty. The drawn line width does not change because the ball comes into contact with the paper surface at a distance, and the edge of the drawn line does not get dirty.

[0021]

The structure and operation of the present invention are as described above, and the thin, thick (soft) core does not break even when a slight writing pressure is applied, and the ball at the tip of the slider sticks to the paper surface during writing. Since it makes contact and rolls, the friction resistance with the paper surface is small and the writing feel is good. Further, since the wear is small, the writing feeling is maintained even when used for a long period of time, and problems such as breaking the paper surface are solved. In addition, the drawn line width is stable and there is no stain.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing a pipe slide type mechanical pencil according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a tip portion of FIG.

3 is a front view of the tip ball portion of FIG. 2. FIG.

FIG. 4 is a longitudinal sectional view of a main part showing an automatic lead-out type mechanical pencil according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a partial judgment surface showing the entire automatic lead-out type mechanical pencil according to the second embodiment of the present invention.

FIG. 6 is an enlarged view of the tip portion of FIG.

7 is a front view of the tip ball portion of FIG. 6. FIG.

FIG. 8 is a vertical cross-sectional view of a main part showing a conventional pipe slide type mechanical pencil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chuck 2 Fastener 3 Shaft cylinder 4 Outer shell 5 Core case 6 Shaft part 7 Spring 8 Base 9 Slider 10 Shaft part 11 Holding chuck 12 Receiving member 12a Receiving seat 13 Holder 14 Ball 15 Caulking part 16 Core 17 Core guide pipe 20 Shaft cylinder 20a Step portion 20b Inner step 21 Chuck case 22 Core fixing chuck 23 Ball 23 `Ball 24 Coil spring 25 Tightening cylinder 26 Slit part 27 Locking part 28 Core case 28a Collar part 28b Collar part 29 Shaft part 30 Projection 31 Coil spring 32 Base 33 slider 34 shaft portion 35 holding chuck 36 holder 37 fixing tool 38 coil spring 39 receiving member 40 ball 41 caulking portion 42 core guide pipe 43 slit 44 bulging portion 44a protrusion 45 groove 46 knock cover 47 eraser stopper Tool 48 Eraser 50 Chuck 51 Tightener 52 Shaft cylinder 53 Core case 54 Shaft part 55 Core guide 56 Locking part 57 Spring 58 Mouthpiece 59 Slider 60 Shaft part 61 Gripping piece 62 Engaging part 63 Pressure contact piece 64 Holding chuck 65 Core insertion Hole 66 Tip pipe 67 Core

Claims (3)

[Claims] 1. A mechanical pencil configured to grip and release a lead by a back-and-forth movement of a chuck arranged at the tip of the barrel and to feed the lead, the center of the tip of a mouthpiece attached to the tip of the barrel. A slider is provided in the hole, which is capable of retracting as the core wears. A plurality of balls are rotatably held via a holder at the tip of the slider, and a central hole is formed by contacting each ball. A mechanical pencil characterized in that a lead guide pipe is provided, and the lead is inserted into the lead guide pipe. 2. The slider has a holding chuck for frictionally holding a core at a rear end thereof, a receiving member for restricting the backward movement of the ball is provided on the front side, and the holder is externally mounted while the ball is seated on the receiving member. Wherein the ball is non-detachable and rotatably held, a core guide pipe is provided at the center of the receiving member, and the ball is provided so as to slightly project from the tip of the core guide pipe. The mechanical pencil described in 1. 3. The structure in which the core fixing chuck is tightened with a ball has sufficient core gripping force for writing.
In mechanical pencils that require only a small amount of force to pull out the lead from the chuck, the lead is pulled out from the chuck into the center hole of the tip of the die attached to the tip of the barrel, and is always moved forward by a spring. The automatic lead-out mechanical pencil according to claim 1 or 2, further comprising a slider that is energized and is capable of retracting as the lead wears while writing.