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(11) | EP 0 065 828 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Writing tip |
| (57) A writing tip for use with aqueous ink, comprising an elongate housing which contains
at one end a writing ball 3, at the other end a fibrous feed core 4 extending into
the housing. Between the writing ball and the fibrous feed core is a transfer member,
which is generally in form of another ball 2. This transfer ball is in contact with
both the fibrous feed core and the writing ball to provide a more positive ink transfer
to the writing ball. |
[0002] Writing tips for use with aqueous ink are known, and comprise an elongate housing, a ball retained in a socket at one end of the housing, and a fibrous feed core having aqueous ink feeding capillaries extending into a bore of the housing from the other end thereof, for transferring aqueous ink to the ball via a grooved feed passage in the housing between the bore and the socket, as for example in U.K. Patent No. 2025857.
[0003] In these known tips the core is intended to be located in abutting relationship with the end of the grooved feed passage remote from the ball, but ink transfer to the ball is often unreliable, primarily because of poor transfer cf ink from the core to the grooved feed passage, for example, due to an axial gap between the ends of the core and grooved feed passage intended to be in abutting relationship.
[0004] For a more positive transfer of ink to the ball, the ball itself may abut the core, but this leads to problems of friction between the core and the ball. This friction, means that the ball may not rotate very freely, and thus the writing tip, diags on the paper and is unpleasant and difficult to write with.
[0005] According to the present invention there is provided a writing tip for use with aqueous ink, wherein an elongate housing contains at one end a writing ball, held in a socket, and at the other end a fibrous feed core having capillaries extending at one end into a bore of the housing, characterised by the provision of transfer member means located in the housing, and having a convex surface portion in contact with the writing ball, and a further surface portion in contact with the fibrous feed core.
[0006] This transfer member means may be a ball, and preferably has then substantially the same diameter as the writing ball.
[0008] The housing may preferably include a plurality of feed channels into which parts of the said one end extend.
[0009] The invention also provides a pen equippedwith a writing tip as described above, and preferably including an ink reservoir into which the feed core extends.
[0010] It will be appreciated that insertion of the core into the feed channel in the manner defined above provides positive contact between the core and the ball, making the transfer of ink therefore more positive due to abutment contact.
[0011] In order that the invention may be well understood an embodiment thereof, which is given by way of example only, will now be described, reference being made to the accompanying drawings, in which:
Figure 1 is a longitudinal section of a writing tip.
Figures 2, 3 and 4 are respectively sections of the tip taken along the lines 2-2 and 3-3 and 4-4 of Figure 1.
[0012] The illustrated writing tip is for use with aqueous ink and comprises an elongate housing 1, a transfer ball 2, a writing ball 3, and a feed core 4 extending into a bore 7 in the housing 1 from the end 8 thereof. Balls 2 and 3 are retained in a socket 5 at the other end 6 of the housing 1. Feed core 4 transfers ink from a scarce (not shown) to the ball 2 via feed channels 9 situated-between the bore 7 and the socket 5. The housing is also provided with an annular abutment 10 by which it can be located in a writing instrument.
[0013] The core 4 is formed as a stick of longitudinally extending man-made fibres which are bonded together with a resin to provide aqueous ink feeding capillaries for feeding ink to the ball 2 from the ink source, for example, a transorbe or reservoir in a writing instrument into which end portion 11 of the core extends in use.
[0015] To provide good tranfer of ink between the core 4 and ball 2, the core 4 is inserted into the end 12 of the feed channels 9 remote from the ball 2. The material of the core is uncompressed within the feed channels 9 and assumes the cross-section of the feed channels 9. Figure 2 shows core 4 filling feed channels 9. The stop face 13 is positioned to abut the base 20 of ball 2 which is located on seating surface 15. The insertion of core 4 into feed channels 9 in an uncompressed condition is made possible by the protrusion into the bore 7 of the angular projections 14 which extend away from ball 2.
[0016] The bore 7 is provided with longitudinal flats 16 which radially locate and also secure, the core 11 in the bore 7.
[0017] The writing ball 3 which is located in socket 5 is retained by lip 17 and is held in contact but free to revolve against ball 2 which is located on seating 15 supporting ball 3 in this condition.
[0018] When ball 3 is revolved due to the motion of writing ink is transferred from core 4 to ball 3, and excess ink will then collect in the reservoir 18 which is formed by the radial volume adjacent to the contact point between said balls.
1. A writing tip for use with aqueous ink, wherein an elongate housing (1) contains
at one end (6) a writing ball (3) in a socket (5) and at the other end (8) a fibrous
feed core (11), having capillaries 13 extending at one end (13) into a bore (7) of
the housing (1), characterised by the provision of transfer member means (2), located
in the housing (1), and having a convex surface portion in contact with the writing
ball (3) and a further surface portion in contact with the fibrous feed core (11).
2. A writing tip as claimed in claim 1, further characterised in that the transfer
member means (2) is a ball.
3. A writing tip as claimed in claim 2, further characterised in that the writing
ball (3) and the transfer ball (2) have substantially the same diameter.
4. A writing tip as claimed in any of the preceding claims, further characterised
in that the transfer means comprises a plurality of transfer members.
5. A writing tip as claimed in any of the preceding claims characterised further in
that the housing (1) includes a plurality of feed channels (9) and parts of said one
end (13) of the feed core extend into the feed channels.
6. A pen, characterised by being provided with a writing tip as claimed in any one
of claims 1 to 5.
7. A pen, as claimed in claim 6, and further characterised by including an ink reservoir
into which the feed core extends.