GB2078175A

GB2078175A - A ball-point pen

Info

Publication number: GB2078175A
Application number: GB8117548A
Authority: GB
Original assignee: Zebra Co Ltd
Current assignee: Zebra Co Ltd
Priority date: 1980-06-10
Filing date: 1981-06-09
Publication date: 1982-01-06
Also published as: FR2483851A1; GB2078175B; FR2483851B1; JPS574373U; IT1142541B; DE3122980A1; IT8148612A0; DE8117176U1

Abstract

The ball-point pen has a writing tip 12 with a rolling ball 13 in a socket at the outer extremity of the tip and an ink reservoir 11 connected to the tip 12 for supplying ink thereto, the tip 12 and the ink reservoir being in a tubular casing. The tip 12 has an ink flow duct 15 for supplying ink to the ball 13 and a valve chamber 16 arranged contiguous with the duct 15 at the inner extemity of the tip 12. The chamber 16 has a larger inside diameter than that of the duct 15, whereby an annular shoulder 14 is formed at the juncture of the two diameters. A plurality of ink flow grooves 14 min are formed in the shoulder 14 which interconnect the chamber 16 with the duct 15 via inlet openings 14 sec . A ball 17 is housed within the chamber 16 to be freely movable in the axial direction of the chamber 16. A seat 18 having an opening 19 of smaller diameter than that of the ball 17 is provided at the end of the chamber 16 remote from the shoulder 14. When the pen is pointed upwardly, the ball 17 seats itself on the seat 18 under gravity to close the opening 19 and thus prevent backward flow of ink from the tip 12 into the reservoir 11. <IMAGE>

Description

SPECIFICATION Ball-point pen This invention relates to a ball-point pen comprising a tubular casing having a writing aperture at one end, a writing tip located in said aperture and having a rolling ball for writing held in a socket at the outer extremity of said tip, and an ink reservoir connected to said tip for supplying ink thereto and accommodated in said casing.

When such a ball-point pen is used to write with its tip directed upwards or when it is left pointing upwards when not in use, the ink within the tip will flow backwards into the reservoir, so that the amount of ink within the tip will become insufficient, making writing difficult or even impossible.

To prevent such back flow of ink, there has already been proposed in Japanese Utility Model Publication No.5661/1972, a ball-point pen in which the forward end of the tip is provided with a valve chamber having a diameter reduced somewhat from that of the ink flow duct of the ink reservoir, the valve chamber having a valve ball housed therein in a free floating manner so that the back flow of ink within the tip is prevented.

In a ball-point pen having such a construction, it is necessary to provide a valve chamber at the forward extremity of the tip adjacent to the ball for writing and, moreover, to form within said valve chamber both small grooves for the passage of ink and a valve seat for the valve ball. Thus, manufacture of the valve chamber involves troublesome machining work that must be carried out with high precision, making it difficult to produce the pen on an industrial scale.

It is an object of the invention to provide a ballpoint pen with a mechanism for preventing the back flow of ink which has a very simple construction, which obviates the need for precise and troublesome machine processing of the valve chamber and makes the ball-point pen readily adaptable to production on an industrial scale.

Accordingly, the present invention consists in a ball-point pen comprising a tubular casing having a writing aperture at one end, a writing tip located in said aperture and having a rolling ball for writing held in a socket at the outer extremity of said tip, and an ink reservoir connected to said tip for supplying ink thereto and accommodated in said casing, wherein the writing tip has an axial ink flow duct for supplying ink from the ink reservoir to said ball, a valve chamber arranged contiguous with said flow duct at the inner extremity of said tip and having a larger inside diameter than that of said flow duct, whereby an annular shoulder is formed at the juncture of the two diameters which is provided with a plurality of ink flow grooves interconnecting the valve chamber with the flow duct, a valve ball accommodated within said valve chamber to be freely movable in the axial direction of said valve chamber, and a valve seat, having an opening of smaller diameter than that of said valve ball, arranged at the end of said valve chamber remote from said shoulder, the ball valve cooperating with said valve seat, with the tip pointing upwards, to prevent backward flow of ink from the tip into the ink reservoir.

In order that the invention may be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example an embodiment thereof, and in which: Fig. 1 is a longitudinal sectional view, showing the internal construction of a conventional ballpoint pen, Fig. 2a is a longitudinal sectional view of the tip and part of the ink reservoir of a ball-point pen according to the invention shown with the pen pointing upwards, Fig. 2b is a sectional view taken along line A-A of Fig. 2a, and Fig. 3 is a longitudinal sectional view similar to Fig. 2a with the pen shown pointing downwards as used for writing.

As shown in Fig. 1 , the conventional ball-point pen comprises a tubular casing 4 which accommodates an ink reservoir 1 to which is connected a writing tip 2 located in an aperture at one end of the casing and having a rolling ball 3 serving for writing which is held in a socket at the outer extremity of the tip 2.

In Figs. 2 and 3, reference numeral 11 denotes an ink reservoir which is accommodated in the usual pen casing (not shown). A writing tip 1 2 is closely fitted to one end opening of the reservoir 11 and holds a rolling ball 13, serving for writing, in a socket at the outer extremity of the tip 12. An axial ink flow duct 1 5 extends from the ball socket to the interior of the ink reservoir 11 for supplying ink to the ball 13. At its inner extremity the diameter of the duct 1 5 is enlarged to form a valve chamber 1 6 with an annular shoulder 14 in which a plurality of uniformly distributed ink flow grooves 14' are formed having inlet openings 14".

A valve ball 1 7 is received within the valve chamber 1 6 to be freely movable axially thereof. A valve seat 18 is formed by reducing the diameter of the wall at the end of the valve chamber remote from the shoulder 14 so as to form an opening 19 of smaller diameter than the diameter of the valve ball 17.

The primary feature characterising this invention is that the valve seat 1 8 of the valve chamber 1 6 is provided not adjacent the outer extremity of the tip 12 as in the conventional mechanism for preventing ink back-flow, but at the inner or rear end of the tip, so that the valve seat 1 8 can be produced by a simple shaping operation such as a drawing operation for reducing the diameter of the rearward portion of the wall of the valve chamber 1 6. Furthermore, instead of forming the valve seat 1 8 by working the rear end portion of the wall of the valve chamber 16, a separate preformed valve seat may be fitted to the outer portion of the valve chamber.

Reference numeral 20 indicates an annular shoulder on the tip 12 which serves as an abutment when the tip 12 is inserted into the ink reservoir 11.

In particular, the ink flow grooves 14' arranged in the annular shoulder 14 are preferably distributed uniformly on the inner wall of the tip 12 in such a manner that at the time of normal writing (Fig. 3) the ink from the reservoir 11 will freely pass through the ink flow grooves 14' into the flow duct 1 5 and that, as shown in Fig. 2a, the openings 14" of the ink grooves 14' will exist on the end face of the shoulder 14. It is to be understood that the diameter of the valve ball 17 is dimensioned so that it can float within the valve chamber 1 6 in the longitudinal direction of the tip 1 2 and can be seated on the shoulder 14 when the pen is in a downwardly directed state (at the time of writing).

Since the ball-point pen according to the invention has the construction described above, when the tip of the pen is upwardly directed as shown in Fig. 2a, the valve ball 1 7 is seated on the valve seat 1 8 under its own weight to close the opening 19. Accordingly, the ink within the ink flow duct 1 5 of the tip 12 does not pass through the opening 1 9 of the valve seat 18, thus preventing back flow of the ink within the tip 12 into the ink reservoir 11.

On the other hand, at the time of writing as shown in Fig. 3, the valve ball 17 is seated on the shoulder 14 of the tip 12 under its own weight.

The ink flow grooves 14' are, however, not closed, so that the ink is smoothly supplied from the ink reservoir 11 to the ball 13 through the opening 1 9, the ink flow grooves 14' and the central ink flow duct 1 5.

Claims

1. A ball-point pen comprising a tubular casino having a writing aperture at one end, a writing tip located in said aperture and having a rolling ball for writing held in a socket at the outer extremity of said tip, and an ink reservoir connected to said tip for supplying ink thereto and accommodated in said casing, wherein the writing tip has an axial ink flow duct for supplying ink from the ink reservoir to said ball, a valve chamber arranged contiguous with said flow duct at the inner extremity of said tip and having a larger inside diameter than that of said flow duct, whereby an annular shoulder is formed at the juncture of the two diameters which is provided with a plurality of ink flow grooves interconnecting the valve chamber with the flow duct, a valve ball accommodated within said valve chamber to be freely movable in the axial direction of said valve chamber, and a valve seat, having an opening of smaller diameter than that of said valve ball, arranged at the end of said valve chamber remote from said shoulder, the ball valve cooperating with said valve seat, with the tip pointing upwards, to prevent backward flow of ink from the tip into the ink reservoir.

2. A ball-point pen, substantially as herein described with reference to and as shown in Figs.

2a, 2b and Fig. 3 of the accompanying drawings.