US 3881828 A
The invention provides a pen nib of ink-permeable metal foam or ink-permeable plastics foam. The foam material used for the pen nibs should be of open-cell structure with the apertures between the cells constituting the pores of the structure.
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Description (OCR text may contain errors)
United States Patent 1191 Jones 1 May 6, 1975  PENS AND NIBS THEREFOR 2,684,052 7/1954 Rickmeyer 401/199 X 3,111,702 11/1963 Berger 401/199  lnvemor' F'edemk Bracknen 3,628,876 12/1971 Casey et a1. 401/198 England  Assignee: Wilkinson Sword Limited, High FOREIGN PATENTS OR APPLICATIONS wycombe, Buckinghamhire, 1,561,844 14/1970 Germany 401/198 England 1,160,331 2/1958 France 401/198 1,948,778 12/1970 Germany 131/261  Filed: July 12, 1973  Appl. No.: 378,619 Primary Examiner-Lawrence Charles Attorney, Agent, or Firm-Brooks Haidt Haffner & [30 Foreign Application Priority Data DeLaHum July 18, 1972 United Kingdom 33436/72  ABSTRACT 'i ml/199; 75/20 The invention provides a' pen nib of ink-permeable  Fieid 199 metal foam or ink-permeable plastics foam. The foam 75/20 f 29/108 material used for the pen nibs should be of open-cell structure with the apertures between the cells consti-  References Cited tuting the pores of the structure.
UNITED STATES PATENTS 9 Claims, 1 Drawing Figure 2,434,775 1/1948 Sosnick 75/20 FD PENS AND NIBS THEREFOR The present invention relates to pens and to nibs therefor.
Fibre-tipped pens, whilst convenient to use and relatively inexpensive to produce, are disadvantageous in that their fibre nibs tend to wear rapidly in use. The nibs of fibre-tipped pens are conventionally formed from bonded fibres, the strength of the nib increasing as the proportion of the periphery of each fibre bonded to adjacent fibres is increased. However, ink flows through such a nib via voids between the fibres and consequently the effective porosity of the nib decreases as the degree of bonding between the fibres is increased; for this reason the degree of bonding between the fibres in the nib is necessarily a compromise so as to provide reasonable strength without occupying sufficient space to impede the flow of ink.
According to the present invention there is provided a pen nib of ink-permeable metal foam or inkpermeable plastics foam.
The invention further provides a pen having an ink reservoir and a pen nib of ink-permeable metal foam or ink-permeable plastics foam.
The foam material used for the pen nibs should be of open-cell structure with the apertures between the cells constituting the pores of the structure.
One construction of pen and pen nib in accordance with the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing which is a sectional side view of the pen and pen nib.
In this construction the pen has a barrel 10 containing a porous filler 10a, for example a cellulosebased material, which constitutes the ink reservoir. One end of the barrel 10 is formed with an opening 10b to receive a nib 11 which may be ofa force fit in the opening 10b or may be staked by a pin (not shown) or secured in any other suitable manner. After the reservoir 100 has been filled the end of the barrel l remote from the nib It is closed by a plug 12.
Where the nib is of an ink-permeable metal foam, the foam may, for example, be of nickel, or a nickel/- chromium alloy, or of an iron/chromium alloy, nickel/- chromium alloys being particularly suitable.
Preferably the cell spaces in the foam amount to from 30 to 80 percent of the total volume of the foam and the mean pore size is preferably from 10 to 10 metres with a cell size not greater than 3 X 10 metres. The larger mean pore sizes are required for relatively viscous inks and a mean pore size of from 1 to 5 X metres is usually suitable for water-based inks. The thickness of the metal between the pores is preferably at least one tenth of the mean pore size.
Where the nib is of an ink permeable plastics foam it may, for example, be of a polyalkylene, particularly polyethylene or polypropylene, a polyurethane or a polyamide. particularly a nylon. The pore sizes are preferably similar to those for the metal foams referred to above. Since plastics materials generally have a relatively low Youngs Modulus (approximately 100,000 p.s.i. in contrast to approximately 20,000,000 p.s.i. for metals), nibs formed from a foam of plastics material can be more readily deformed under pressure so that the width of a line produced thereby can be varied. Ad-
vantageously the nib has a thin surface coating of a metal or alloy to improve the wear characteristics of the nib without substantially reducing its overall resilience. Suitably the surface of the nib is electroplated with a strong wear-resistant metal such as, for example, nickel or chromium.
Pen nibs in accordance with the present invention and having tip dimensions similar to those of conventional fibre nibs can be produced having lower wear rates than such fibre nibs. This means that a nib in accordance with the invention can have an ultimate tip of smaller dimensions than that of conventional fibre nibs but with commensurate useful life.
Increased ink flows can be obtained with nibs in accordance with the invention compared with fibre nibs to permit faster writing speeds to be used. Furthermore, such increased ink flows can be obtained with nibs having at least as good, and frequently better, wear properties and mechanical strengths than fibre nibs.
Although the construction described above has the ink reservoir formed separately from the nib, the reservoir may be formed integral with the nib.
Nibs can be formed from ink-permeable metal foam material by deformation, for example, by rolling, drawing or swaging, to reduce the cross-section of the pores of the foam and to elongate the cells in the direction of the ink flow. Nibs with square or hexagonal cross section may be produced. Furthermore, an integral nib/reservoir assembly can be produced by likewise deforming one end of a length of a foam metal to form the nib, the remaining portion of the length of material forming a reservoir having larger cells with a higher ink-carrying capacity per unit volume than the nib.
1. A pen nib composed of a relatively rigid, inkpermeable metal foam material, said foam material having an open-cell structure, said structure having apertures between the cells, said apertures constituting the pores of the structure.
2. A pen nib according to claim 1, wherein the foam material has from 30 to percent of its total volume as cell space.
3. A pen nib according to claim 1, wherein the foam material has a mean pore size of from 10 to l0 metres with a cell size less than 3 X 10 metres.
4. A pen nib according to claim 3, wherein the thickness of material between the pores of the foam is at least one tenth of said mean pore size.
5. A pen nib according to claim 1, wherein the foam material is of nickel.
6. A pen nib according to claim 1, wherein the foam material is of a nickel/chromium alloy.
7. A pen nib according to claim 1, wherein the foam material is of an iron/chromium alloy.
8. A pen nib composed of a relatively rigid, inkpermeable metal foam material, said foam material having a structure of open-cells with from 30 to 80 percent of its total volume as cell space and with the size of the cells less than 3 X 10" metres, said structure having apertures between the cells, said apertures having a mean pore size of from 10 to 10 metres.
9. A pen nib according to claim 8, wherein the cells are elongated in the direction of ink flow.