JPS632800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a ballpoint pen characterized in that a ball bearing part is plastically worked on the end of a metal tube, and a small diameter ink flow hole communicating with the ball bearing part and an ink guiding groove are simultaneously formed. This invention relates to a method for manufacturing chips. Traditionally, the production of ballpoint pen tips begins with
After a ball bearing part is formed, a small diameter ink flow hole for conducting ink to the ball support part and a plurality of ink guide grooves connected to the small diameter ink flow hole are sequentially formed. Usually, the main part of the ball was formed through a process of caulking the fitted ball. Therefore, the required processing steps require a considerable number of steps, including the drilling of the small-diameter ink flow holes and the large-diameter ink flow holes that communicate with the ink guide grooves, and are well known to those skilled in the art. For some time now,
Improvement of this was strongly desired.

In view of these circumstances, the present invention, as described above, involves establishing a new process for simultaneously plastic working the ball bearing part that forms the main part of the ballpoint pen tip, and the small-diameter ink flow hole and ink guiding groove that communicate with this ball bearing part. The present invention aims to provide a simple and inexpensive method for manufacturing a ballpoint pen tip that greatly reduces the number of steps. Hereinafter, the present invention will be explained in detail with reference to the drawings.

The outer peripheral surface of one opening 2 of the metal tube 1 is the clamping tool 3
held by. The clamping tool 3 has two or more clamping parts 3a, and a predetermined gap 4 is maintained between the respective end faces 3b while the clamping tool 3 clamps the outer peripheral surface of the opening 2 of the metal tube 1. There is. 1st
4 to 4 show the ball bearing portion 5, the small diameter ink flow hole 6 and the ink guide groove 7 formed by the method of the present invention.
This is an explanatory diagram of the process in which the metal tube 1 is molded at the same time.
In this state, the punch 8 having an outer diameter larger than the inner diameter of the opening 2 is held until the bottom surface 8a stops within the axial length range of the holding part 3a. When the opening 2 is pushed in from above, the ball support 5, the small-diameter ink flow hole 6, and the ink guide groove 7 are molded at the same time. In other words, by pushing the punch 8, the inner surface of the opening 2 is squeezed to form the holding part 5a and the bottom part 5b that constitute the ball support part 5.
The flesh squeezed in this forming process protrudes inward at the portion that clamps the outer peripheral surface of the opening 2, and conversely, the flesh at the portion corresponding to the gap 4 between the end surfaces 3b of the clamping portion 3a protrudes outward. As a result, a substantially triangular through hole is formed in the bottom portion 5b of the ball support portion 5. This approximately triangular through hole is formed over a length equivalent to the wall thickness of the bottom portion 5b of the ball support portion 5, and most of it becomes the small diameter ink flow hole 6.
The corner portion formed in the relatively narrow groove-like portion becomes the ink guiding groove 7 (see FIG. 3). Thus, the ink guiding groove 7 contributes to the ink supplying action of the small-diameter ink flow hole 6 and promotes the conduction of ink to the ball support portion 5.

5 and 6 explain examples in which the number of clamping parts 3a of the clamping tool 3 is changed, but when the number of clamping parts 3a is two, a substantially rectangular small-diameter ink flow The hole 6 is formed and the holding part 3a
When the number of holes is four, approximately rectangular small-diameter ink flow holes 6 are formed. In this case, it goes without saying that each corner portion becomes the ink guiding groove 7. The number of clamping portions 3a may be set to other values if desired, so that the gap 4 between the end faces is kept constant, and the corner portions are connected to the small diameter ink flow holes 6 to be formed. It may be determined as appropriate as long as it is possible. In this way, the ball bearing part 5, the small-diameter ink flow hole 6, and the ink guiding groove 7 are molded at the same time, but after that, the ball 9 fitted in the ball bearing part 5 is removed from the outside of the metal tube 1 by an appropriate means. 10, the main part of the ballpoint pen tip is completed (see Fig. 4).

As described above, the present invention clamps the outer peripheral surface of the opening of a metal tube with a clamping tool having two or more clamping parts and maintaining a predetermined gap between the respective end faces in the clamping state, Since a new process is added to squeeze the inner surface of the opening in this state, the ball bearing part, small-diameter ink flow hole, and ink guiding groove can be molded at the same time, reducing the number of steps required to manufacture a ballpoint pen tip. Since it has become possible to significantly reduce the amount of ink, it has become possible to obtain ballpoint pen tips that can smoothly conduct ink to the ball bearing portion easily and at low cost.

[Brief explanation of the drawing]

Figures 1 to 4 are explanatory diagrams of the case where the inner surface of the opening is squeezed using a clamping tool having three clamping parts, and Figure 1 is an explanation of the state before the punch is pushed in. Figure 2 is an explanatory diagram of the inside of the metal tube after the punch is inserted, Figure 3 is a top view of Figure 2, and Figure 4 is an explanation of the process of caulking the ball fitted into the ball support. It is also a diagram,
FIGS. 5 and 6 are explanatory diagrams of embodiments in which the number of clamping parts of the clamping tool is varied. 1... Metal tube, 2... Opening, 3... Clamping tool, 3a...
Holding portion, 3b... End face, 4... Gap, 5... Ball support portion, 6... Small diameter ink flow hole, 7... Ink guide groove.

Claims (1)

[Claims] 1 A ball bearing is formed at the end of the metal tube, and then a small diameter ink flow hole and an ink guide groove are provided at the bottom of the ball bearing, and then the ball fitted in the ball bearing is caulked from the outside of the metal tube. In a method for manufacturing a ballpoint pen tip, the above-mentioned ballpoint pen tip is manufactured by using a clamping tool having two or more clamping parts and configured such that a predetermined gap is maintained between the end faces of these clamping parts respectively in the clamped state. Hold the outer circumferential surface of the opening of the metal tube, and then press a punch with an outer diameter larger than the inner diameter of the opening from above the opening to form a ball support and simultaneously form a small-diameter ink flow hole and an ink guide groove. A method for producing a ballpoint pen tip characterized by molding it.