GB2074104A - Fountain pen - Google Patents

Abstract

Pen cartridge (30) has a double lip (36, 38, 40) seal and an interior open end (35) which is adapted to fit over cylindrical boss (24) and conduct the ink into a bore (26, 28) which extends through the boss and communicates with feed bar (15). The tapered nose end (35) of the cartridge (30) snugly fits into the bore of the casing (12), adjacent the boss (24), which communicates with the feed bar (15). <IMAGE>

Description

SPECIFICATION Fountain pen Cartridges for feeding ink in fountain pens have been known in the art particularly as represented by U.S.A. Patent 3,532,436 (Koenig) and U.S.A. Patent 3,521,969 (Mutschler). These cartridges have generally taken the form of a nipple-like end which is adapted to extend over a pin or stud and extends into a casing on the side remote from a feed bar. The fitting of the cartridge, made of plastics material, over a protruding part is solely limited by the friction of the cartridge engaging type stud, for example. As is well known, all deformable materials tend to lose their resiliency and in time with structures of this nature leakage can occur.

The present invention relates to an improved fountain pen which has the usual writing point and feed bar contained in the forward end of a casing which is divided adjacent the inner end of the feed bar by a bore containing capillary feed channels and a passageway for air. The partition is particularly defined by a boss which extends into the casing on the side of the partition opposite the feed bar. A cartridge to contain ink has a closed upper end and a nose portion with an open lower end, the open end engaging the outer diameter of the boss. The inner wall of the lower end is particularly defined by a sealing means defined by a double lip protrusion which snugly fits in sealing engagement with the outer diameter of the boss.The sealing means has an inner diameter smaller than the outer diameter of the boss and the tapered nose engaging the inner wall of the casing not only forces the sealing means inwardly, but also itself provides a seal. Further, the open end of the nose engages the partition and achieves a still further seal.

The arrangement of the double lip sealing of the cartridge aboutthe boss achieves a number of beneficial results. Firstly, the inner pressure within the casing of the cartridge will act on the inner portion of the lip forcing it under pressures which may exceed normal atmospheric pressure to press it against the boss. Additionally, any atmospheric pressures act on the other portion of the lip in a similar fashion, compensating for any pressure differentials, and with this structure the seal between the cartridge and the boss may be readily perfected. To maintain the seal, the cartridge has a stepped, tapered nose portion which seats in the casing. The cartridge is stabilized by a casing part with a stepped interior and'when the tapered stepped nose portion is seated, there will be at least two spaced contacts.This construction not only axially stabilizes the cartridge and prevents any air from entering through the seal which would upset the fine balance in the ink feed system of the fountain pen, the seal being forced radially inward.

Also the nose seats against the partition and the side walls seat against the inner wall of the casing, providing additional sealing as noted above.

The accompanying drawings illustrate an embodiment of the invention which is at present preferred.

In these drawings: Fig. 1 is a longitudinal elevation of a fountain pen, with parts broken away and shown in section; Fig. 2 is a section on line 2-2 of Fig. 1; Fig. 3 is an enlarged partial sectional view of the sealing of the cartridge to the pen.

Referring now to the drawings, the fountain pen illustrated in Fig.1 has the usual nib 10 which extends from a casing 12 and which is assembled on the feed bar 15, all of which is held in the casing by a securing nut 16. The end of the casing 12 remote from the nib has an interior threaded section 18. A partition 20 in the casing 12 has an outer threaded portion which engages casing threads 18 and a front end 22 which abuts the feed bar 15. The opposite end of the partition has firstly an elongated boss 24 with a bore 26 having one or more capillary channels 28 located therein and secondly an inner wall of the threaded portion which is coaxial with the boss 24.

A rear casing part 12' acts as a continuation of the main casing 12 and has a reduced end 13 which defines a shoulder 14 fitting snugly into and abutting the rear end of the casing 12. Screw threads 17 on the exterior of the casing part 12' receive the threaded portion of an end cap (not shown) while the interior bore receives the cartridge 30. The interior bore of the casing which receives the cartridge effectively has two diameters, namely a larger diameter at the part 12' and a smaller diameter by the inner wall of the partition member 20. In effect, the bore may be defined as a stepped bore to receive the cartridge 30.

Acartridge or ink reservoir 30 comprises essentially a hollow cylindrical body which may be formed of a suitable semi-rigid material such as plastic material, for example, polyethylene. The cartridge 30 has an outer cylindrical part 31 with a rear end wall 32, an intermediate tapered part 33 and atapered nose part 34. The latter has a front end 35 from the inner portion of which there extends a double lip seal 36 which defines a pair of lips 38 and 40. Also shown within the cartridge, is a ball 42 which initially seals the cartridge by extending across the double lip bore, it being opened by displacement when the lower end of the cartridge is inserted over the boss 24. The double lip formation 36 defines a forward lip 38 and a rearward lip 40.The rearward lip 40 is acted upon by the pressure of the ink within the cartridge 30 so that if the pressure within the cartridge increases, the lip 40 will be forced against the bore 24 with a greater force, thus preventing ink within the cartridge 30 from being forced out of it. Similarly should for some reason there be an excessive pressure on the outer portion exposed to the atmosphere at the location of the lip 38 a similar action will occur, thus ensuring that all times regardless of the ambient pressures in existence, the cartridge will tightly seal about the boss 24. To further ensure sealing the tip 35a of the nose front end engages the partition 20.

The cartridge is shown as fully seated in the drawing and in this position the forward nose part engages the inner wall of the partition member at 48 to provide a seal and force the seals 36 inwardly.

Additionally, the intermediate portion 33 engages the outer end of the casing as at 50. As will be apparent, points 48 and 50 are spaced apart and support the cartridge in its seated position. The support stabilizes the cartridge and prevents upset of the lip seal. The tapered sections also permit ease of insertion of the cartridge into the casing.

Claims (4)

1. A fountain pen having a casing which supports the nib, and a feed bar; a partition in the casing adjacent the feed bar and having a cylindrical boss extending away from the feed bar; the boss having a through bore with capillary slots in its wall; a cartridge having a closed end and an open end; the open end having a sealing means located on its inner wall and inwardly of the open end and an exterior tapered nose, inner wall casing means engaging the tapered nose, the sealing means defining a protrusion with inwardly and outwardly extending lips, the inner diameter of the sealing means being smaller than the outer diameter of the boss, the engagement of the tapered nose with the inner wall forcing the sealing means inwardly whereby a tight joint is achieved, and said open end engaging the partition to provide an additional seal.

2. Afountain pen according to claim 1 wherein the nose of the cartridge is stepped and tapered and the casing has a stepped inner wall to receive the cartridge.

3. Afountain pen according to claim 1 or claim 2 wherein the partition comprises a re-entrant bore defining a cylindrical inner wall within the casing extending aboutthe cylindrical boss.

4. Afountain pen constructed substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.