JPS62225395A - Manufacture of ball pen tip - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for making a ballpoint pen tip, which includes a step of providing a constricted portion at the tip of the tip so that it gradually becomes narrower in the direction ηλ.

[Conventional technology]

As a method for manufacturing a ballpoint pen tip having the above-mentioned steps, for example, as in Japanese Patent Application Laid-Open No. 58-191199, the tip g4 of a metal -1 is pressed inward around its entire circumference to hold the tip. A constricted portion is provided by forming the constricted portion so as to gradually narrow in accordance with the same manner, and a hole is removed from the inner structure of the constricted portion through the hole opening at the end of the constricted portion to form a ball holding cylinder portion and a ball pedestal portion. The holding part has a groove bottom, and the ball pedestal part has holes 4 formed along the through hole for introducing ink, and the ball holding part is formed with a hole 4 along the through hole. After inserting the ball into the # part, there is a model that uses force/mechanism on the tip opening ring N to force the ball to rest in the sliding part.
After the narrowed part is formed in this way, cutting is normally performed, but in this case, as shown in Fig. 3, the Taber shaft part (3) at the narrowed part (2) of the metal capillary tube (1) is cut. If the angle is not accurate, the cutting tool (5) will not be able to contact the reference plate (4) accurately and the contact angle of the cutting tool (5) will be incorrect, resulting in defective products as shown in the figure. To prevent this, As shown in FIG. 2, high precision is required for the angle of the narrowed portion (2). By the way, the thin metal tubes used for ballpoint pen tips have an outer diameter of about 2 mm, and inserting a core metal inside the tube is not a good idea for small-scale production, but for mass production at low cost. This is difficult due to the fact that the core metal is often damaged, so it is processed without a core metal, but as the difference between the outer diameter of the original shape and the outer diameter after processing is increased, the narrowed part ( There is an inward escape (6) near the center of 2).
) (see Fig. 4), and there is a drawback that the accuracy of the angle of the narrowed portion (2) cannot be guaranteed. In addition, if the amount of deformation is large when forming the narrowed part, a large processing force is naturally required, and this force may also affect areas other than the part where the narrowed part is formed, such as the rear part of the pipe, causing buckling etc. Therefore, there is a disadvantage that the number of processing steps for processing the narrowed portion is increased to suppress the load in one step, which requires many man-hours to adjust the processing machine and lowers productivity.

[Problem that the invention seeks to solve]

As mentioned above, the manufacturing method for ballpoint pen tips, which includes the process of forming a narrowed part at the tip of a thin metal tube, has not yet appeared on the market because it is difficult to mass produce and cannot provide inexpensive products. is the current situation. Taiyomei's purpose is to improve this manufacturing method and provide a method that can provide ballpoint pen tips that are inexpensive and of high quality.

[Means for solving problems]

The method for manufacturing a ballpoint pen tip of the present application, which was devised to achieve the above object, includes the step of forming a constricted portion that gradually becomes 9-round toward the tip. It is characterized by providing a stepped portion in the middle.

[Embodiment 11 PII] Fig. 1 shows a drawing of the narrowing processing process of a simple embodiment of the present invention. 8) to form a parallel shaft portion (9) with an appropriate outer diameter d1 in the middle before reaching the final outer diameter d2 at the tip, and a tapered shaft portion (10) continuing behind the parallel shaft portion (9). 1 (a)), then raise the bottom dead center of the drawing die (8) by a required distance and narrow it again to form a parallel step of the required length at the rear end position of the original parallel shaft portion (9). A fitting part (11) is provided, and a tapered shaft part (12) is provided in front of the attached part (11).
) and a final outer diameter d2 (see Figure 1 (b)), the narrowing process is completed, and then (illustration omitted) the above-mentioned second narrowing part ( The ball holding part is configured by drilling holes in the inner walls of the parallel shaft part (13) and the Taber shaft part (12) from the direction of the opening of the tip to form a ball holding cylinder part and a ball pedestal part. A groove for ink introduction is formed along the through hole by broaching,
Thereafter, a ball is inserted into the ball holding part, the edge of the tip opening is caulked, and the ball is held in the ball holding part, thereby producing a ballpoint pen tip.

[Action and effect]

The present invention is constructed like a savior, and by providing a stepped part (11) in the middle of the narrowing part at an intermediate stage of the narrowing process, the second narrowing process thereafter Since the contact area of the drawing die (8) at
), it has the effect of reducing the machining load compared to conventional methods, thereby eliminating the influence of the load on the rear part of the narrowed part of the metal tube, and eliminating the cause of buckling etc. This also has the effect of improving productivity because the number of processing steps can be reduced and the time required for adjusting the processing machine can be shortened. Also, by providing the stepped portion (11), the angle accuracy of the narrowed portion is determined by considering only the angle of the Taber shaft portion (12) in front of the stepped portion (11) that occurs in the secondary narrowing process. The angle of the Taper shaft part (1o) behind the stepped part (11) does not require high precision, and the angle of the Taper shaft part (12) is parallel at the end of the first narrowing process. Since the shaft part (9) is narrowed and formed, the rate of change in the outer diameter is small and the occurrence of the relief (6) shown in Fig. 4 is prevented, making it easier to guarantee high angular accuracy of the narrowed part. It also has the effect of stabilizing dimensions during cutting. In addition, when providing the stepped portion, it is sufficient to simply raise the bottom dead center of the drawing die (8) by the required distance at an appropriate stage of the overall narrowing process, and no new process is required, which may lead to an increase in cost. do not have.

As described above, the manufacturing method of the present invention is highly effective in stably supplying inexpensive, high-quality ballpoint pen tips. Of course, this method may also be applied to a conventional method of providing a tapered portion by cutting. In other words, it is possible to reduce the cutting l of the standard chi/〈 section, which brings good results to the tool life, and because the angle / 11 degrees of other taper sections is hardly required, it leads to a reduction in tool cost. This effect can be expected.

[Brief explanation of drawings]

Figure 1 shows the implementation sequence of the present invention, and Figures 2 and 3, which are cross-sectional views of the narrowing process, show the cutting process after the conventional narrowing process. Figure 2 is a trj diagram of a misfire when the angle of the narrowed part is normal, Figure 3 is a trj diagram of a misfire when the angle of the narrowed part is abnormal, and Figure 4 shows the escape during the 71st machining process of the conventional example. It is a cross-sectional view showing the resulting state. (1)...Gold yAa tube, (2)...Narrowed portion, (3)
... Taber limbus, (41 ... reference plate, (!5
1...Cutting tool, (6)...Escape, (71...Gold am tube, (8)...Drawing die, (9)...Parallel shaft part, αa...Taber shaft part , α...stepped part, a2...
・Taber shaft part, αto...parallel shaft part. Watch Applicant: Mitsubishi Lead Rainbow Co., Ltd. Ward 4

Claims (1)

[Claims] 1. A method for manufacturing a ballpoint pen tip comprising a step of providing a constricted portion that gradually narrows toward the tip, the method comprising providing a stepped portion in the middle of the constricted portion.