US3303826A

US3303826A - Fountain pen nib

Info

Publication number: US3303826A
Application number: US447621A
Authority: US
Inventors: Lewis M Cowden; William J Roach
Original assignee: Union Carbide Corp
Current assignee: Union Carbide Corp
Priority date: 1965-04-13
Filing date: 1965-04-13
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14

Description

Feb. 14, 1967 L, M. COWDEN ETAL 3,303,826

FOUNTAIN PEN NIB Filed April 13, 1965 INVENTORS LEWIS M. COWDEN WILLIAM J. ROACH @m wr ATTORN EY United States Patent Ofiice 3,303,826 Patented Feb. 14, 1967 This invention relates to pens, and particularly, to fountain pen nibs.

Generally speaking, the nibs for fountain pens consist of either gold or stainless steel for resistance to the corrosive effects of the ink flowing through the pen. While these materials resist the corrosive effects, they do constitute a wear problem on the writing surface. To overcome this wear problem, high quality prior art pen nibs have ruthenium pellets fused to the nib for its writing surface. While this solves the wear problem for the nib, the process for applying the pellets is very time consuming and expensive. In addition, in fusing such pellets to the nib, great difficulty is experienced in keeping the slit through which ink passes centrally aligned Within the nib.

It is, therefore, the principal object of the present invention to provide a novel pen nib which has a good wear resisting writing surface and in which the writing surface is easily made.

According to the invention, the wear surface of the pen nib is coated with chrome oxide, the coating being formed by a plasmarc process. More particularly, powders of chrome oxide are passed through an arc torch in the manner described in U.S. Patent N0. 3,016,447, and then projected onto a base, which in the case of the present invention would be the tip of the nib of the pen. Because of the torchs constricting nozzle, the arc becomes well-stabilized thus yielding an intense columnar plasma. The torch itself operates in a non-transferred mode. Coatings formed according to this are process have a dense laminar structure with bonded overlapping leaves.

In the drawing, the single figure is a fragmentary bottom plan view of an ink fountain pen illustrative of the invention.

Nib 1%, which is held in holder 12, has a writing surface 14 that is about in diameter. The ink from the fountain pen is fed to the writing surface through a slit 16. In order to insure a smooth, even flow of ink, slit 16 must be centrally aligned within the nib of the pen. As previously stated, high quality prior art pen nibs used a ruthenium pellet fused to the nib to serve as the writing surface. This invention involves coating the Writing surface with chrome oxide by the process previously described.

In applying the coating, the slit 16 is first formed in the nib. During the coating operation, the nib is separated along the slit. This procedure insures that the slit will be centrally aligned. Such alignment otherwise would be difiicult to achieve after the writing surface has been coated with the relatively hard chrome oxide.

The following table indicates the type of wear surfaces that have been used for the Writing surface and the length of life that each has provided.

Time Before Material Used Vickers Defect Hardness Appeared (hours) Ruthenium Pellet 470 175 A1203 Coating 1,000 11%; Chrome Oxide C0ating 1, 300 1 500 1 No defect.

In addition to the wear requirements, the writing surface should also be such that the pen will not scratch when being used. For this reason, a single-phase coating is preferred. Thus, if a two-phase coat-ing such as tungsten carbide, is used the pen will scratch because the required finish of the coating cannot be achieved.

The following example indicates the conditions used to achieve a good coating on the writing surface of the pen nib. In the example, the torch in the process of the above-mentioned U.S. Patent No. 3,016,447 was used.

Six pen nibs were coated by the above-mentioned process. The Writing surface had a diameter of about & The torch was held about A to 1" away from the coating surface. The balance of the nib, that is the rest of the nib that does not serve as a writing surface, was masked. Argon gas was fed through the torch at the rate of about 300 c.f.h. Powdered chrome oxide was fed through the torch with the aid of argon gas at the rate of about grns./min. A coating about .002" thick was obtained in about six seconds.

After the coating was applied, the surfaces were finished by conventional grinding and lapping means. The measured finish was less than 0.5 R.'M.S., this being about the lowest measured value obtainable by conventional measuring means.

What is claimed is:

As an article of manufacture, a fountain pen nib comprising a base composed of metal selected from the class consisting of gold and stainless steel, said nib having an adherent plasmarc process applied hard la-m-ellar chrome oxide coating at least on the writing tip thereof, which not only resists wear but is substantially scratch free in use.

References Cited by the Examiner UNITED STATES PATENTS 2,039,326 5/1936 Lukens 109 3,016,447 1/1962 Gage et .al 21926 References Cited by the Applicant UNITED STATES PATENTS 3,016,447 1/1962 Gage et al.

LAWRENCE CHARLES, Primary Examiner.