Method of surface texturing for a writing instrument tip

Patent metadata

Field	Value
Publication number	US-12005536-B2
Application number	US-202017753218-A
Country	US
Kind code	B2
Filing date	Sep 11, 2020
Priority date	Sep 11, 2019
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A method of manufacturing a metallic ball pen tip for a writing instrument comprising a feeding passage extending in an axial direction, the feeding passage reaching in a housing configured to receive a ball, the housing being defined by a cylindrical wall and a wall, the method comprising the steps providing a preform of the metallic ball pen tip comprising the feeding passage and the housing, the housing being defined by the cylindrical wall and a wall, machining the wall so as to obtain a stepped wall, broaching feeding grooves in the stepped wall and coining the stepped wall with a spherical die so as to obtain the ball seat, and a metallic ball pen tip obtained by the method.

First claim

The invention claimed is:

1. A method of manufacturing a metallic ball pen tip for a writing instrument comprising a feeding passage extending in an axial direction, the feeding passage reaching in a housing configured to receive a ball, the housing being defined by a cylindrical wall and a ball seat, wherein the ball seat comprises a plurality of feeding grooves and wherein the ball seat is textured, the method comprising the steps of:
providing a preform of the metallic ball pen tip comprising the feeding passage and a housing preform, the housing preform being defined by the cylindrical wall and a ball seat preform wall;
machining the ball seat preform wall so as to obtain a stepped wall;
broaching the feeding grooves in the stepped wall;
coining the stepped wall with a spherical die so as to obtain the textured ball seat.

2. The method according to claim 1 , wherein the ball seat preform wall forms an angle with the axial direction equal to or greater than 0° and equal to or smaller than 80°.

3. The method according to claim 1 , wherein the ball seat preform wall forms an angle with the axial direction equal to or greater than 20° and equal to or smaller than 55°.

4. The method according to claim 1 , wherein the machining of the ball seat preform wall removes material from a portion of the ball seat preform, proximal to the opening of the feeding passage, and extends in an axial direction towards an ink reservoir of the writing instrument, wherein the machining of the ball seat preform wall is carried out in two steps, a first step of machining a first group of steps and a second step of machining a second group of steps.

5. The method according to claim 4 , wherein the steps of the stepped wall each include a progressively smaller radius as measured relative to a central longitudinal axis that extends along a length of the writing instrument,
such that a first step is located adjacent to the housing and has a radius relative to the central longitudinal axis; a second step, immediately adjacent to the first step in a direction away from an opening of the ball tip, having a radius smaller than the radius of the first step; and a third step, immediately adjacent to the second step and in a direction away from the opening of the ball tip, having a radius smaller than that of the radius of the first step and the radius of the second step, and
wherein the steps of the first group alternate with the steps of the second group.

6. The method according to claim 1 , wherein each step has a depth, measured in a radial direction perpendicular to the axial direction, equal to or greater than 10 μm and equal to or smaller than 50 μm.

7. The method according to claim 1 , wherein each step has a depth, measured in a radial direction perpendicular to the axial direction, equal to or greater than 25 μm and equal to or smaller than 40 μm.

8. The method according to claim 1 , wherein each step has a height, measured in the axial direction, equal to or greater than 10 μm and equal to or smaller than 60 μm.

9. The method according to claim 1 , wherein each step has a height, measured in the axial direction, equal to or greater than 13 μm and equal to or smaller than 50 μm.

10. The method according to claim 1 , wherein the spherical die is pressed in the axial direction with a force equal to or greater than 40 N.

11. The method according to claim 1 , wherein the spherical die is pressed in the axial direction with a force equal to or greater than 93 N.

12. The method according to claim 1 , wherein the spherical die is made of hard carbides.

13. The method according to claim 1 , wherein the spherical die is made of tungsten carbide.

14. The method according to claim 1 , wherein the stepped wall comprises five steps.

15. The method according to claim 1 , wherein the metallic ball pen tip is made of a metallic alloy comprising brass.

16. The method according to claim 1 , wherein the metallic ball pen tip is made of a metallic alloy comprising nickel silver.

17. The method according to claim 1 , wherein the metallic ball pen tip is made of a metallic alloy comprising stainless steel.

18. A metallic ball pen tip for a writing instrument manufactured by the method according to claim 1 .

19. The method of claim 1 , wherein the stepped wall is proximal to an opening of the feeding passage and within an interior of the preform of the metallic ball pen tip.

20. The method of claim 1 , wherein each step of the stepped wall includes a flat surface that faces an opening of the ball tip, wherein each flat surface is substantially perpendicular to a central longitudinal axis that extends through the writing instrument.

Assignees

• SOCIéTé BIC

Inventors

• Bouchet Julien
• Larue Stéphane
• Pestour Eric

Classifications

• B43K7/10

  Arrangements for feeding ink to the ball points (B43K7/01 takes precedence) · CPC title

• B43K1/084 Primary

  Ball beds · CPC title

• B21D22/025

  for tubular articles · CPC title

• B23P15/00 Primary

  Making specific metal objects by operations not covered by a single other subclass or a group in this subclass · CPC title