Patent Description:
Metallic ball pen tips are known and comprise a ball received in a housing, the ink being delivered on the writing support, such as a sheet of paper, by a ball received in a housing of the ball pen tip, the ball moving relative to a ball seat of the ball pen tip. For example, <CIT> discloses a method for producing the ball seating surface by coining, preferably by impression of the writing ball itself and <CIT> discloses a ballpoint pen point smooth in writing hand feeling and a ballpoint pen.

Currently, it remains desirable to improve the smoothness of writing and to reduce tip wear.

Therefore, according to embodiments of the present disclosure, a method of manufacturing a metallic ball pen tip for a writing instrument is provided. The metallic ball pen tip includes 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:.

The ball seat preform wall may form an angle with the axial direction equal to or greater than <NUM>°, specifically equal to or greater than <NUM>° and equal to or smaller than <NUM>°, specifically equal to or smaller than <NUM>°.

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, the steps of the first group being alternated with the steps of the second group.

Each step may have a depth, measured in a radial direction perpendicular to the axial direction, equal to or greater than <NUM>, specifically equal to or greater than <NUM> and equal to or smaller than <NUM>, specifically equal to or smaller than <NUM>.

Each step may have a height, measured in the axial direction, equal to or greater than <NUM>, specifically equal to or greater than <NUM> and equal to or smaller than <NUM>, specifically equal to or smaller than <NUM>.

The spherical die may be pressed in the axial direction with a force equal to or greater than <NUM> N, specifically equal to or greater than <NUM> N.

The spherical die may be made of hard carbides, specifically tungsten carbide.

The stepped wall may comprise five steps.

The metallic ball pen tip may be made of a metallic alloy comprising brass or nickel silver or stainless steel.

According to embodiments of the present disclosure, a metallic ball pen tip for a writing instrument is provided. The metallic ball pen tip is manufactured by the above-described method.

With such a method, it is possible to manufacture a metallic ball pen tip for a writing instrument with a textured ball seat. The textured ball seat allows improving the smoothness of writing and to reduce tip wear. Thanks to the texture of the ball seat, it is possible to ensure the presence of a continuous layer of ink between the ball and the ball seat, the continuous layer of ink allowing for smoothness in writing.

It is intended that combinations of the above-described elements and those within the specification may be made, except where otherwise contradictory.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles thereof.

Reference will now be made in detail to exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings.

<FIG> shows a representation of an exemplary writing instrument <NUM> according to embodiments of the present disclosure. The writing instrument <NUM> may include a body <NUM> extending along an axial direction A. The writing instrument may comprise a metallic ball pen tip <NUM>, which is mounted on the body <NUM> of the writing instrument <NUM> through a mounting sleeve <NUM>. The writing instrument <NUM> may also comprise a cap <NUM> for protecting the metallic ball pen tip <NUM>.

As can be seen on <FIG>, the mounting sleeve <NUM> may also connect the metallic ball pen tip <NUM> to an ink reservoir <NUM>. The ink reservoir <NUM> stores ink <NUM> which is to be delivered by a ball <NUM> received in the metallic ball pen tip <NUM>. The ink reservoir <NUM> may be in fluidic connection with the ball <NUM> through the mounting sleeve <NUM> and the metallic ball pen tip <NUM>.

The metallic ball pen tip <NUM> may be made of brass or nickel silver or stainless steel, for example.

As shown in <FIG>, the metallic ball pen tip <NUM> may comprise a feeding passage <NUM> extending in the axial direction A. The feeding passage <NUM> may extend from one axial end of the metallic ball pen tip <NUM> to a housing <NUM>. As shown in <FIG>, the housing may be defined by a cylindrical wall <NUM> and a ball seat <NUM>. The ball seat <NUM> may comprise a plurality of feeding grooves <NUM>. The feeding grooves <NUM> may allow the ink <NUM> to flow from the ink reservoir <NUM> into the housing <NUM>, especially when the ball <NUM> is received in the housing <NUM>.

As shown in <FIG>, the ball seat <NUM> is textured.

<FIG> shows a flow chart of the method <NUM> of manufacturing the metallic ball pen tip <NUM> for the writing instrument <NUM> according to embodiments of the present disclosure.

The method <NUM> comprises a step of providing <NUM> a preform 14A of the metallic ball pen tip <NUM> comprising the feeding passage <NUM> and a housing preform 28A. As shown in <FIG>, in the preform 14A, the housing preform 28A is defined by the cylindrical wall <NUM> and a ball seat preform wall <NUM>. The ball seat preform wall <NUM> may be a conical wall and may form an angle α with the axial direction A. For example, the angle α may be equal to <NUM>°.

The method <NUM> comprises a step of machining <NUM> the ball seat preform wall <NUM> so as to obtain a stepped wall <NUM>.

The step of machining <NUM> the ball seat preform wall <NUM> is carried out in two steps. A first step 104A of machining a first group of steps <NUM> and a second step 104B of machining a second group of steps <NUM>. In a non-claimed example, the step of machining the balls seat preform wall <NUM> may be carried out in more than two steps.

As shown in the enlargement of <FIG>, the steps <NUM> of the first group are alternated with the steps <NUM> of the second group.

The step of machining <NUM> the ball seat preform wall <NUM> may be carried out using a machining tool <NUM>, as shown in <FIG>. As shown in <FIG>, the machining tool <NUM> may be used during the second step 104B to machine the second group of steps <NUM>, which are alternated with the first group of steps <NUM> already machined in the first step 104A of machining, so as to obtain a machined preform 14B.

As shown in the enlarged portion of <FIG>, the steps <NUM> may each have a height H36, measured in the axial direction A, and a depth D36, measured in a radial direction R, perpendicular to the axial direction A.

As shown in the enlarged portion of <FIG>, the stepped wall <NUM> of the machined preform 14B may comprise five steps <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. Each step <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> may have a height measured in the axial direction A and a depth measured in the radial direction R. Step <NUM>-<NUM> may have a height H36-<NUM> equal to <NUM> and a depth D36-<NUM> equal to <NUM>. Step <NUM>-<NUM> may have a height H36-<NUM> equal to <NUM> and a depth D36-<NUM> equal to <NUM>. Step <NUM>-<NUM> may have a height H36-<NUM> equal to <NUM> and a depth D36-<NUM> equal to <NUM>. Step <NUM>-<NUM> may have a height H36-<NUM> equal to <NUM> and a depth D36-<NUM> equal to <NUM>. Step <NUM>-<NUM> may have a height H36-<NUM> equal to <NUM> and a depth D36-<NUM> equal to <NUM>. This is only a non-limiting example and the stepped wall <NUM> may comprise a different number of steps <NUM>.

As an alternative, which does not form part of the present invention, the step of machining the ball seat preform wall <NUM> may be carried out in one step with a machining tool. The machining tool has a cutting shape corresponding to the shape of the stepped wall <NUM>. In this non-claimed example, the steps are all machined at the same time in one machining step.

The method <NUM> comprises a step of broaching <NUM> the feeding grooves <NUM> in the stepped wall <NUM>.

The method <NUM> comprises a step of coining <NUM> the stepped wall <NUM> with a coining tool <NUM> comprising a spherical die <NUM>, so as to obtain the ball seat <NUM>.

The spherical die <NUM>, and the coining tool <NUM>, may be made of hard carbides, specifically tungsten carbide.

The spherical die <NUM> may be pressed in the axial direction A with a force F equal to or greater than <NUM> N, specifically equal to or greater than <NUM> N.

The coining step <NUM> allows deforming the steps <NUM> of the stepped wall <NUM> and provides a non-smooth surface with a texture to the ball seat <NUM>. The deformation of the steps <NUM> is visible on the textured ball seat <NUM> and identified as being made by the deformation of a stepped wall.

<FIG> shows another exemplary metallic ball pen tip <NUM>, which does not form part of the present invention. The exemplary metallic ball pen tip <NUM> of <FIG> is similar to the exemplary metallic ball pen tip of <FIG>.

The exemplary metallic ball pen tip <NUM> of <FIG> may comprise a feeding passage <NUM> extending in the axial direction A. The feeding passage <NUM> may extend from one axial end of the metallic ball pen tip <NUM> to a housing <NUM>. The housing may be defined by a cylindrical wall <NUM> and a ball seat <NUM>. The ball seat <NUM> may comprise a plurality of feeding grooves <NUM>. The feeding grooves <NUM> may allow the ink <NUM> to flow from the ink reservoir <NUM> into the housing <NUM>, especially when the ball <NUM> is received in the housing <NUM>.

The exemplary metallic ball pen tip <NUM> of <FIG> is obtained by the method described herein below, which does not form part of the present invention.

The method <NUM> may comprise a step of providing <NUM> a preform 14A of the metallic ball pen tip <NUM> comprising the feeding passage <NUM> and a housing preform 28A. As shown in <FIG>, in the preform 14A, the housing preform 28A may be defined by the cylindrical wall <NUM> and a ball seat preform wall <NUM>. The ball seat preform wall <NUM> may form an angle α with the axial direction A. For example, the angle α may be equal to <NUM>°.

The method <NUM> may comprise a step of machining <NUM> the ball seat preform wall <NUM> so as to obtain a stepped wall <NUM>.

As shown in <FIG>, the step of machining the ball seat preform wall <NUM> may be carried out in one step. As shown in <FIG>, the stepped wall <NUM> of the machined preform 14B may comprise one step <NUM>. This is only a non-limiting example and the stepped wall <NUM> may comprise a different number of steps <NUM>.

The method <NUM> may comprise a step of broaching <NUM> the feeding grooves <NUM> in the stepped wall <NUM>. <FIG> shows a cross-section of the broached preform 14C, i.e., the machined preform 14B after the step of broaching <NUM> the feeding grooves <NUM> in the stepped wall <NUM>.

The method <NUM> may comprise a step of coining <NUM> the stepped wall <NUM> with a coining tool <NUM> comprising a spherical die <NUM>, so as to obtain the ball seat <NUM>.

The coining step <NUM> allows deforming the step <NUM> of the stepped wall <NUM> and provides a non-smooth surface with a texture to the ball seat <NUM>. The deformation of the steps <NUM> is visible on the textured ball seat <NUM> and identified as being made by the deformation of a stepped wall.

Throughout the description, including the claims, the term "comprising a" should be understood as being synonymous with "comprising at least one" unless otherwise stated. In addition, any range set forth in the description, including the claims should be understood as including its end value(s) unless otherwise stated. Specific values for described elements should be understood to be within accepted manufacturing or industry tolerances known to one of skill in the art, and any use of the terms "substantially" and/or "approximately" and/or "generally" should be understood to mean falling within such accepted tolerances.

Where any standards of national, international, or other standards body are referenced (e.g., ISO, etc.), such references are intended to refer to the standard as defined by the national or international standards body as of the priority date of the present specification. Any subsequent substantive changes to such standards are not intended to modify the scope and/or definitions of the present disclosure and/or claims.

Claim 1:
A method (<NUM>) of manufacturing a metallic ball pen tip (<NUM>) for a writing instrument (<NUM>) comprising a feeding passage (<NUM>) extending in an axial direction (A), the feeding passage (<NUM>) reaching in a housing (<NUM>) configured to receive a ball (<NUM>), the housing (<NUM>) being defined by a cylindrical wall (<NUM>) and a ball seat (<NUM>), wherein the ball seat (<NUM>) comprises a plurality of feeding grooves (<NUM>) and wherein the ball seat (<NUM>) is textured, the method comprising the method steps of:
- providing (<NUM>) a preform (14A) of the metallic ball pen tip (<NUM>) comprising the feeding passage (<NUM>) and a housing preform (28A), the housing preform being defined by the cylindrical wall (<NUM>) and a ball seat preform wall (<NUM>);
- machining (<NUM>) the ball seat preform wall (<NUM>) in two machining steps, a first machining step (104A) of machining a first group of steps (<NUM>) and a second machining step (104B) of machining a second group of steps (<NUM>), the steps (<NUM>) of the first group being alternated with the steps (<NUM>) of the second group, so as to obtain a stepped wall (<NUM>);broaching (<NUM>) the feeding grooves (<NUM>) in the stepped wall (<NUM>);
- coining (<NUM>) the stepped wall (<NUM>) with a spherical die (<NUM>), so as to deform the steps (<NUM>) of the stepped wall (<NUM>) and provide a non-smooth surface with a texture to the ball seat (<NUM>), so as to obtain the textured ball seat (<NUM>).