JP2004114469A - Method for manufacturing ballpoint pen tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and surely manufacture a ballpoint pen tip having a larger writing angle and a smaller drag. <P>SOLUTION: An outer edge of a tip of a tip body 12 is plastically deformed or removed by cutting by using a thinning tool C having a surface formed at an obtuse angle θ' as compared with a caulking angle θ of a caulking tool B or a cutting blade before a caulking step of forming an angle of a predetermined caulked part 18 with respect to an axial center of the ballpoint pen tip. Thus, a thickness of the tip of the body 12 is formed to a range of 40-60 % of the thickness before working. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to processing of the tip of a ballpoint pen tip, and particularly to thinning of the tip of a tip body.
[0002]
[Prior art]
In describing a conventional technique relating to a caulking process of a ballpoint pen tip, a typical structure of the ballpoint pen tip will be described with reference to FIGS. 1 and 2. Here, FIGS. 1 and 2 are front sectional views of a typical ballpoint pen tip. The ballpoint pen tip is a component that constitutes the tip of the ballpoint pen, and is composed of a ball 11 that is in direct contact with the paper surface and a chip body 12 that holds the ball.
[0003]
The tip body 12 is usually formed by cutting a metal columnar material such as brass, bronze, nickel silver, stainless steel, or the like. The side surface of the chip body 12 has a tapered portion 13 toward the tip. A ball house 14, which is a space for accommodating the ball 11, is provided at the tip.
In addition, a back hole 15 extending from the rear end to the front of the ball house 14 and an ink guide hole 16 connecting the back hole 15 and the ball house 14 are also provided. Further, a radial groove 17 which is arranged radially with respect to the ink guide hole 16 and connects the back hole 15 and the ball house 14 is also provided.
[0004]
The ball house 14 accommodates the ball 11 made of ceramic, cemented carbide, or the like. Further, in order to hold the ball 11 and prevent the ball 11 from dropping out of the ball house 14, a so-called caulking process is performed in which the tip end diameter of the tip body 12 is reduced by caulking. The tip portion of the chip body 12 reduced in diameter by this caulking is called a caulked portion 18. The angle formed between the outer surface of the caulking portion 18 and the axis of the ballpoint pen tip is referred to as a caulking angle θ (see FIG. 2).
[0005]
The swaging is performed using a swaging tool having a contact surface having a predetermined swaging angle θ with respect to the ballpoint pen tip held by the holder A. That is, the contact surface is brought into contact with the tip of the chip main body 12 on which the ball 11 is mounted, and is pressed or rotated while being pressed to be plastically deformed, thereby forming the crimp portion 18 having a predetermined crimp angle θ. The caulking portion 18 has a main function of holding the ball 11 as described above, but at the same time, its shape greatly affects the writing quality of the ballpoint pen.
[0006]
Here, the tip end surface of the tip body 12 is a ring-shaped surface perpendicular to the axis of the ballpoint pen tip before swaging. However, after the crimping process, the tip end face is also crimped inward, so that the outer edge of the tip of the crimping portion 18 is located at the tip end of the chip body 12. This part is called edge 19. The angle between the tangent line between the edge 19 and the ball 11 and the axis of the ballpoint pen is the maximum angle at which the ballpoint pen can be inclined with respect to the paper surface. This angle is called a tangent angle α. Accordingly, as the tangent angle α decreases, the writing angle β increases (see FIG. 2).
[0007]
Therefore, if the edge 19 can be located inward from the tangent, the contact point between the new tangent and the ball 11 will move outward from the original contact point. That is, the tangent angle α can be reduced by the amount of the inward deformation of the edge 19, and the area where the ball 11 can come into contact with the paper surface is increased. Furthermore, it is possible to reduce the catch by the edge 19, and it is possible to provide comfortable writing.
[0008]
Various techniques are provided for such movement or elimination of the edge 19.
There is a so-called two-stage caulking process in which the foremost portion of the caulking portion 18 is further caulked inward (for example, see Patent Document 1), and after the caulking process, the edge 19 at the tip of the caulking portion 18 is plastically deformed or cut. Methods are also known.
[0009]
[Patent Document 1]
Japanese Utility Model Publication No. 2-30309 (Fig. 2)
[0010]
[Problems to be solved by the invention]
The above method and the like can also increase the area where the ball 11 can contact the paper surface. However, the tip portion of the tip main body 12 is thinned to some extent by the predetermined caulking process, and the generated caulked portion 18 has fallen in the ball-point tip axial direction, so that the rigidity against a vertical load is very weak. Therefore, it is difficult to crush only the edge 19 of the caulked portion. Therefore, by performing plastic working or cutting work on the edge 19 of the crimp tip after crimping, the crimping inner surface portion 20 located on the ball house 14 side is inevitably affected by the deformation due to the above-described working.
[0011]
Therefore, in general, a certain effect is obtained in the ballpoint pen for oil-based ink, which is a manufacturing method in which the ball 11 does not generate vertical play that can move in the axial direction of the ballpoint pen tip by contacting the inner surface portion 20 with the ball 11. On the other hand, in the processing of the ballpoint pen for water-based ink, which is caulked so that the caulking inner surface portion 20 does not come into contact with the ball 11, the caulking portion 18 is further deformed by the edge 19 removing process after the caulking process. 11 has a drawback that the vertical play changes, that is, the ink outflow amount changes, and conversely, the quality as a ballpoint pen deteriorates.
[0012]
Therefore, the present invention provides a simpler method for any ball-point pen tip for oil-based ink and water-based ink, and more reliably, to produce a ball-point pen tip having a larger writing angle β and less catch. It is intended to provide a manufacturing method.
[0013]
[Means for Solving the Problems]
In view of the above-described problems, the present invention provides a holding tool A for holding a ball-point pen tip, and a ball-point tip held by the holding tool A, which deforms or removes a tip outer edge portion of the tip body 12 to remove the tip. A method of manufacturing a ball-point pen tip using a thin-wall processing tool C for thinning the thickness of a tip end portion of a main body 12 and a crimping tool B for caulking the tip end of a tip body 12 containing a ball 11 to form a crimping portion 18. Before the caulking process using the caulking tool B that forms a predetermined caulking portion 18 angle with respect to the axis of the ballpoint pen tip, the tip of the tip body 12 is formed using a surface that is obtuse than the caulking angle θ of the caulking tool B. The outer edge portion is plastically deformed or cut away by using a thin processing tool C, so that the thickness of the tip end portion of the chip body 12 is made thinner than before processing, more preferably. Wherein the thinning in the range of 60% or less of 40% prior to processing.
[0014]
“Holder A” refers to a device that can hold a ballpoint pen tip with a chuck or the like. The "thin-wall processing tool for thinning the tip end of the tip body 12" has an obtuse surface with respect to the ball-point pen tip axis compared to the caulking tool B, and the surface can plastically deform the workpiece. Or a tool having a cutting edge and capable of removing a work surface. The “crimping tool B” refers to a tool that forms the crimping portion 18 by caulking the tip of the tip body 12 at the above-described crimping angle θ. The term “crimp angle θ” refers to an angle formed between the outer surface of the tip end of the reduced tip body 12 and the axis of the ballpoint pen tip. The “edge 19” refers to the outermost edge of the caulking portion 18 at the forefront.
[0015]
The tip of the ballpoint pen tip is processed as follows by the ballpoint pen tip manufacturing apparatus according to the present invention. First, after fixing the chip body 12 with the holder A, the ball 11 is inserted. Then, the edge 19 of the caulked portion 18 is removed by plastic working or cutting. At this time, since the portion to be processed is substantially parallel to the axis of the ballpoint pen tip, the portion to be processed has rigidity against a vertical load, and the influence of the processing of the outer edge of the tip end of the tip body 12 does not affect the diameter of the ball house 14.
[0016]
When the tip outer edge of the tip body 12 is processed by plastic working, for example, a tool having two pairs of rotatable rollers having the same shape as the swaging tool B may be used, or an annular surface having a slope at the tip may be used. A pressed tool having a pressure may be used.
In any case, the processed surface of the tool is brought into contact with the edge 19 of the caulking portion 18 to reduce the thickness of the tool within a range of the tip body 12 preferably having a tip end thickness of preferably 40 to 60% before processing. Until it moves down along the ballpoint pen tip axis. By doing so, the entire circumference of the outer edge of the tip body 12 can be uniformly thinned.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. In the ball-point pen tip manufacturing apparatus according to the present embodiment, a stainless steel columnar material can be held by the holder A having the chuck. Further, in addition to a cutting tool for cutting this cylindrical material, a tool such as a drill having various diameters for forming a through hole or a blind hole in the cylindrical material, a crimping tool B and a thin-walled processing tool C described later are provided. I have. The holder A is movable between the tools while holding the columnar member. As a result, the processing of the ballpoint pen tip is automatically performed.
[0018]
First, a stainless steel cylinder is held by the holder A. Then, cutting is performed with a cutting tool to form a tip body 12 having a tapered portion 13 on the side surface toward the tip. Further, a back hole 15 is drilled from the rear end, and an ink guide hole 16 and the ball house 14 are drilled from the tip. After the back hole 15 and the ball house 14 pass through the ink guide hole 16, a radial groove 17 radially positioned with respect to the ink guide hole 16 is passed. Then, the ball 11 made of cemented carbide is mounted on the ball house 14. At this time, it is desirable that the amount h of protrusion of the ball from the tip of the chip body 12 is about 30% of the diameter of the ball 11.
[0019]
【Example】
FIG. 3 shows an example of thinning. In (a), the shape is the same as the crimping tool B, but the thin-walled processing tool C having an obtuse angle θ ′ smaller than the crimping angle θ is made to coincide with the axis, and the processed surface is positioned at the outer edge of the tip body 12 tip. Get closer. Then, the edge 19 is crushed by plastically deforming the outer edge of the tip end of the chip main body 12 with the thin processing tool C. At this time, in order to make full use of the effect of the thin processing, the tip wall thickness of the tip body 12 after the plastic deformation is set to be in a range of 40% to 60% of the thickness before the processing. Here, if the above range is less than 40%, an effect is obtained with respect to catching at the time of writing, but the target value of the thickness after the thin-wall processing becomes a very small value, so that it is difficult to process. And stable supply is difficult. Further, in a ball-point pen tip equipped with a small-diameter ball, the holding power of the ball 11 itself is significantly reduced, which seriously affects the quality of the ball-point pen. On the other hand, if it is larger than 60%, it is difficult to obtain a sufficient effect because the possibility that the thin-walled processed surface disappears by the subsequent caulking step increases. Therefore, the thickness of the tip end after thinning is optimally 40% to 60% of the thickness before processing.
[0020]
Thereafter, in b), a predetermined crimping process is performed by using a crimping tool B having a crimping angle θ, so that it is below the tangent line between the crimping portion edge 19 and the ball 11 when only the crimping process is performed. Can be moved to the edge 19. Here, a ballpoint pen tip for water-based ink using a ball diameter φ0.7 mm will be specifically described as an example. The ball projection amount h of the ballpoint pen tip used as a writing instrument from the tip body 12 is generally about 30% of the diameter of the ball 11 regardless of the ball diameter. The thickness before thinning is 25 μm.
[0021]
When the thickness of the tip end portion of the tip body 12 is smaller than 40% of the thickness before processing, that is, when the thickness is smaller than 10 μm, a large processing force is required in the thin-wall processing. The deformation of the portion 20 is promoted, and the vertical play of the ball 11 changes as in the related art, thereby changing the amount of ink flowing out, leading to quality variation. Further, since the wall thickness is several μm, processing becomes very difficult, and stable supply is difficult.
[0022]
Conversely, if the tip body 12 tip thickness is greater than 60% of the thickness before processing, that is, greater than 15 μm, thin processing is performed due to large plastic deformation of the tip body 12 in the subsequent caulking step. The possibility that the part processed surface disappears increases. Furthermore, the closer the value of the thin-walled processing angle θ ′ and the value of the crimping processing angle θ are, the higher the possibility of disappearance of the thin-walled processed surface becomes. When the thin-walled processed surface disappears, the shape becomes the same as that of a normal manufacturing method, so that the original purpose of reducing the effect of reducing the catch at the time of writing cannot be obtained.
[0023]
Therefore, the thickness of the tip end 12 after thinning is optimally 40% to 60% of the thickness before processing.
As shown in FIG. 4, the tangent angle α2 of the ball-point pen formed in this manner after crimping is smaller than the original tangent angle α1. Therefore, the writing angle β2 after plastic deformation can be made larger than the original writing angle β1. That is, plastic deformation of the tip outer edge of the chip body 12 can increase the area where the ball 11 can come into contact with the paper surface.
[0024]
In the conventional method, since it was processing to an unstable portion after caulking, there was a problem such as a change in vertical play, processing was difficult unless it is a ball-point pen tip for oil-based ink, but by the method of the present invention In addition, since the occurrence of vertical play can be prevented, the ballpoint pen for water-based ink can also be easily processed. And comfortable writing can be achieved.
[0025]
Further, since there is no deformation of the crimping inner surface portion 20 before and after the thinning, the thinning itself can obtain the same effect before and after the ball 11 is inserted.
The fact that it is possible to perform thin-wall processing using the thin-wall processing tool C before inserting the ball 11 means that thin-wall processing can be performed without worrying about interference with the ball 11, which is safer and easier. There is an advantage that various methods and tools can be used.
[0026]
Furthermore, in the case of thin-wall processing in which the tip body thickness of the tip body 12 before thin-wall processing is thin and has no rigidity, it is also possible to insert a core rod in thin-wall processing, so even in such a case. There is an advantage that the processing can be performed more safely so that the inner surface portion 20 of the crimping is not deformed.
As the thin-walled processing tool C, a tool similar to the above-described caulking tool B may be used. However, since a similar shape can be obtained by using a pressing tool having an annular surface having a slope at the tip, the effect is small. can get. In addition to the plastic deformation, it is also possible to remove the outer edge of the tip body 12 by cutting, and the effect of the present invention can be obtained similarly to the above-described method.
[0027]
【The invention's effect】
With the above configuration, the present invention has the following effects. That is, according to the description in the claims, it is possible to provide a manufacturing method for simply and surely manufacturing a ballpoint pen tip having a larger writing angle β and less catch.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a representative shape of a ballpoint pen tip and its holder.
FIG. 2 is a front sectional view showing a typical shape of a tip portion of a ballpoint pen tip.
FIG. 3 is a schematic view showing an example of the production method of the present invention. Note that the ballpoint pen tip is shown in a front sectional view, and the caulked portion is shown in detail.
FIG. 4 is a front sectional view showing a change in a tangent angle and a writing angle after caulking by a conventional manufacturing method and after caulking by a manufacturing method according to the present invention. The details of the swaged portion are shown.
[Explanation of symbols]
Reference Signs List 11 ball 12 tip body 13 taper portion 14 ball house 15 back hole 16 ink guide hole 17 radial groove 18 crimping portion 19 edge 20 crimping inner surface portion A holder B crimping tool C thin-walling tool θ crimping angle θ ′ thin-walling angle α tangent line Angle β Writing angle α1 Original tangent angle β1 Original writing angle α2 Tangent angle when thinning is performed β2 Tangent angle h when thinning is performed h Ball protrusion

Claims (2)

A holding tool for holding the ballpoint pen tip, and a thin-walling tool for deforming or removing the tip outer edge of the tip body with respect to the ballpoint pen tip held by the holding tool, and thinning the tip body tip portion wall thickness. A method of manufacturing a ballpoint pen tip using a caulking tool that forms a caulked portion by caulking the tip end of a chip body containing a ball,
Before the caulking process using a caulking tool that forms a predetermined caulking part angle with respect to the axis of the ballpoint pen tip, thinning the tip outer edge of the tip body using a surface that becomes obtuse than the caulking angle of the caulking tool A method of manufacturing a ballpoint pen tip, wherein the tip of the tip body is made thinner than before processing by plastic deformation or cutting and removal using a tool. A holding tool for holding the ballpoint pen tip, and a thin-walling tool for deforming or removing the tip outer edge of the tip body with respect to the ballpoint pen tip held by the holding tool, and thinning the tip body tip portion wall thickness. A method of manufacturing a ballpoint pen tip using a caulking tool that forms a caulked portion by caulking the tip end of a chip body containing a ball,
Before the caulking process using a caulking tool that forms a predetermined caulking part angle with respect to the axis of the ballpoint pen tip, thinning the tip outer edge of the tip body using a surface that becomes obtuse than the caulking angle of the caulking tool A method of manufacturing a ballpoint pen tip, wherein the tip of a tip body is thinned within a range of 40% or more and 60% or less before machining by plastic deformation or cutting and removal using a tool.

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