EP1074402A1 - VERFAHREN ZUM HERSTELLEN VON RöHRCHENKUGELSCHREIBERSPITZEN - Google Patents

VERFAHREN ZUM HERSTELLEN VON RöHRCHENKUGELSCHREIBERSPITZEN Download PDF

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Publication number
EP1074402A1
EP1074402A1 EP00903964A EP00903964A EP1074402A1 EP 1074402 A1 EP1074402 A1 EP 1074402A1 EP 00903964 A EP00903964 A EP 00903964A EP 00903964 A EP00903964 A EP 00903964A EP 1074402 A1 EP1074402 A1 EP 1074402A1
Authority
EP
European Patent Office
Prior art keywords
ink
steel tube
hole
tip end
pen tip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00903964A
Other languages
English (en)
French (fr)
Inventor
Toru Mitsubishi Pencil Kabushikikaisha KITAO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Pencil Co Ltd
Original Assignee
Mitsubishi Pencil Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Pencil Co Ltd filed Critical Mitsubishi Pencil Co Ltd
Publication of EP1074402A1 publication Critical patent/EP1074402A1/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K1/00—Nibs; Writing-points
    • B43K1/08—Nibs; Writing-points with ball points; Balls or ball beds

Definitions

  • the present invention relates to a method of manufacturing a ballpoint pen tip from steel tube.
  • Steel tubes have been heretofore used as material of ballpoint pen tips.
  • the intact inside cavity of the steel tube is usually used as an ink hole.
  • plural (usually three) sites near an end of the steel tube are radially punched to be deformed plastically so that the sites may protrude inward to be a ball seat.
  • Each of the sites at which the tube is punched should be located at an equal distance from the end of the tube and be deformed plastically to an equal extent. It is, however, actually difficult to punch the tube as described above. Therefore, since a ball may be partially seated on the ball seat, which is formed partially, there has been an inconvenience that the ink flow amount may be inconstant according to the direction of writing.
  • the ink flow amount may be inconstant according to the variation of the ink hole diameter.
  • the ball seat which has been conventionally fabricated by plastic deformation, is formed by cutting in the same way as in a ballpoint pen tip made of solid cylindrical material.
  • the inner surface of an end of a steel tube is cut to form a ball housing having a conical bottom surface. Then, channels are radially cut from this bottom surface. Thereafter, a ball is inserted in this ball housing. The end of the steel tube is caulked inwardly so that the ball may be held by the steel tube. Subsequently, the ball is struck from a tip end. In this way, the curved surface of the ball is transferred to the conical bottom surface. Namely, this transferred surface becomes a ball seat.
  • the ball seat can be formed uniformly even in a tubular ballpoint pen tip.
  • the present invention is intended to provide a method of fabricating a tubular ballpoint pen tip by cutting, wherein the size of the ink hole as well as the ball seat is constant.
  • the present invention provides a method of manufacturing a tubular ballpoint pen tip by cutting a steel tube, comprising an ink-hole-finishing step in which an inner wall of the steel tube is cut up to a distance of L1 from a tip end with a drill with a caliber of D1, a following channel-boring step in which radial channels are bored against the ink hole up to a distance of L3 from the tip end, and a following cleaning step in which the inner wall of the steel tube is cut up to a distance of L2 from the tip end with a drill a caliber of D2; wherein the following relations are satisfied: L1 ⁇ L2 > L3 and D1 ⁇ D2.
  • One of the advantages of using a steel tube for material of the ballpoint pen tip is that its inside cavity can be used as an ink hole.
  • the inner diameter of the material steel tube is made to be the size of the ink hole of a final product, it inevitably includes an error to a certain extent.
  • the ink-hole-finishing step in which the inner wall of the steel tube is cut with a drill with a caliber of the ink hole in the final product (D1), is performed.
  • the distance (L1) through which this ink-hole-finishing step is carried out does not extend over the full length of the steel tube, but is sufficient to cover a part close to the tip end. An error in the latter portion of the ballpoint pen tip hardly affects the ink flow amount, and it is sufficient to improve the accuracy of the ink hole at the tip end portion.
  • channels are bored after the ink-hole-finishing is applied to the steel tube, and thereafter the cleaning step, in which the inner wall of the ink hole is cut with a drill with a caliber (D2) less than or equal to the inner diameter in the ink-hole-finishing.
  • the cleaning step is carried out with the drill with a smaller caliber, because it is sufficient to eliminate burr produced in the channel-boring step. Namely, the cleaning step is not intended to enlarge the ink hole but to remove the burr protruding inward of the ink hole by the channel-boring step.
  • the caliber D2 is referred to as being "less than” the inner diameter D1
  • the caliber D2 is preferably slightly less than the caliber D1 in order to remove the burr. If the caliber D2 is too small, the burr cannot be removed. Since this cleaning step is not intended to enlarge the ink hole, the caliber of the drill used in this step may be the same as that used in the ink-hole-finishing step.
  • the distance (L2) for cutting in this cleaning step is less than or equal to the distance L1 and greater than the distance (L3) for boring in the channel-boring step because it is sufficient to eliminate the burr produced by the channel boring. Furthermore, since the distance L2 is less than or equal to the distance L1, the distance for cutting in the cleaning step may be equal to the distance for the ink-hole-finishing step.
  • the ink-hole-finishing step it is not limited when the ink-hole-finishing step should be performed.
  • a ball housing (20) may be formed after this step.
  • the ink-hole-finishing step is preferably carried out after the ball housing is formed by cutting the inner wall of the tip end the steel tube, because the burr produced during formation of the ball housing can be eliminated in the ink-hole-finishing step.
  • an inner wall of a tip end of a steel tube is cut and enlarged to form a ball housing. Further, an outer wall of the tip end the steel tube is cut to taper off to form a tapering surface.
  • the inner wall of the steel tube is cut with a drill with a caliber of D1 up to the distance L1 from the tip end. Namely, the inner diameter of the ink hole at the tip end is cut to D1.
  • the inner wall of the steel tube is again cut with a drill with a caliber of D2 up to a distance of L2 from the tip end. Namely, burr produced in the channel-boring step is removed in the cleaning step. Since the caliber D2 is less than or equal to the caliber D1 as mentioned above, the inner diameter of the ink hole will not enlarged.
  • a ball is loaded in the ball housing as in an ordinary procedure. Subsequently, caulking is performed to form a caulked portion. Thereafter, the ball is struck from the tip end to form a ball seat on the bottom surface of the ball housing and also to form a clearance between the ball and the inner edge of the caulked portion.
  • a steel tube 11 for material of a ballpoint pen tip 10 is made of a piece of fine tubular stainless steel with an outer diameter (a) 1.2 to 2.0 times as long as a ball diameter (e) and an inner diameter (b) 0.7 to 0.9 times as long as the ball diameter (e) (Fig. 1A).
  • the material of the steel tube 11 is SUS304, SUS305, SUS316, SUS430, and so on.
  • a tip end of the steel tube 11 is cut and chamfered to form a tip end edge 81 (Fig. 1B).
  • a burr 83 produced at the tip end edge portion 82 by the above-mentioned chamfering is cut and removed so that a temporary tapering surface 84 is formed slightly at the tip end (Fig. 1C).
  • a ball housing 20 is roughly cut from the tip end of the ballpoint pen tip 10 using a drill with a caliber (c) approximately equal to the ball diameter (e) (Fig. 2A).
  • the inside of the ball housing 20 is cut to be finished with a drill with a caliber (d) 1.02 to 1.05 times as long as the ball diameter (e). Moreover, the outer surface of the tip end is cut to form a tapering surface 30 (Fig. 2B). In this way, the bottom surface 21 of the ball housing on which a ball seat will be subsequently transferred is formed.
  • an ink-hole-finished portion 41 is cut up to 0.8 mm (L1) from the tip end with a drill with a caliber (D1) longer than or equal to the inner diameter (b) of the steel tube (Fig. 3A).
  • burrs 31 cf. Figs. 2A, B, and C
  • the variation caused by the error of the steel tube 11 are eliminated.
  • channels 50 are radially formed in the bottom surface 21 of the ball housing 20 up to 0.15 mm (L3) from the tip end toward the rear end with a channel tool (Fig. 3B).
  • a drill with a caliber (D2) less than or equal to D1 is inserted from the tip end up to 0.5 mm (L2) from the tip end in order to remove the burrs 51 produced by the cutting of the channels 50 and to form a cleaned portion 42 (Fig. 3C).
  • a hard-metal ball 70 is inserted into the ball housing 20, and the tip end is caulked to be a caulked portion 60 which holds the ball 70 (Fig. 4A).
  • an ink guide wick (not shown) is inserted from the rear end of the ballpoint pen tip 10 and its tip end is made to bear against the rear end of the ball 70.
  • This ink guide wick is formed by extrusion molding of resin such as polyacetal, and many grooves are formed in its outer surface along it axis. These grooves are capillary tubes to guide ink toward the tip end. Then, the ballpoint pen tip 10 is punched at in the midway thereof to fix the ink guide wick and, thus, the ballpoint pen tip 10 is completed.
  • the method of manufacturing a tubular ballpoint pen tip in accordance with the present invention provides a tubular ballpoint pen tip having a ball seat and an ink hole of stable sizes by cutting.

Landscapes

  • Pens And Brushes (AREA)
EP00903964A 1999-02-19 2000-02-16 VERFAHREN ZUM HERSTELLEN VON RöHRCHENKUGELSCHREIBERSPITZEN Withdrawn EP1074402A1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP4092499 1999-02-19
JP4092499 1999-02-19
PCT/JP2000/000849 WO2000048846A1 (fr) 1999-02-19 2000-02-16 Procede de fabrication d'une pointe tubulaire de crayon a bille

Publications (1)

Publication Number Publication Date
EP1074402A1 true EP1074402A1 (de) 2001-02-07

Family

ID=12594060

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00903964A Withdrawn EP1074402A1 (de) 1999-02-19 2000-02-16 VERFAHREN ZUM HERSTELLEN VON RöHRCHENKUGELSCHREIBERSPITZEN

Country Status (3)

Country Link
EP (1) EP1074402A1 (de)
KR (1) KR20010042179A (de)
WO (1) WO2000048846A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100433945B1 (ko) * 2001-09-26 2004-06-04 동아연필 주식회사 볼펜팁 제조장치 및 방법
US9518317B2 (en) * 2012-05-11 2016-12-13 General Electric Company Method of coating a component, method of forming cooling holes and a water soluble aperture plug

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS392679B1 (de) * 1961-05-01 1964-03-14
JPS5890996A (ja) * 1981-11-26 1983-05-30 株式会社パイロット ボールペンチップの製造方法
JP3037168U (ja) * 1996-10-24 1997-05-06 ゼブラ株式会社 インク逆流防止機構を備えたボールペン
JPH10217665A (ja) * 1997-02-04 1998-08-18 Mitsubishi Pencil Co Ltd ボールペンチップ

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0048846A1 *

Also Published As

Publication number Publication date
WO2000048846A1 (fr) 2000-08-24
KR20010042179A (ko) 2001-05-25

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