GB2073676A

GB2073676A - Socket for a ball point

Info

Publication number: GB2073676A
Application number: GB8109594A
Authority: GB
Original assignee: Pentel Co Ltd
Current assignee: Pentel Co Ltd
Priority date: 1980-03-28
Filing date: 1981-03-26
Publication date: 1981-10-21
Also published as: FR2479101A1; FR2479101B1; DE3112211A1; GB2073676B

Abstract

A socket (6) for holding the writing ball of a ball point pen (20) has an outer tube (10) fixed relative to the casing of the pen and an inner tube (1) inserted into the outer tube (10) and having a funnel shaped portion (4) at one end. A rod type ball seat (3) is located in the inner tube, and a writing ball (2) rotatably supported by the ball seat (3) and the other end of the inner tube (1). <IMAGE>

Description

SPECIFICATION A socket for holding a writing ball of a ball point pen The present invention relates generally to a ball point pen and more particularly to a socket structure for the writing ball of a ball point pen using low viscosity aqueous ink and a very small, rigid ball having a diameter of for example, 0.4 mm or less.

It is quite difficult to produce by cutting, a conical or bullet-like tip having a ball seat rotatably supporting a ball thereon, particularly when the ball has a diameter as small as 0.4 mm or less. An attempt has been made to overcome this disadvantage, by adapting a rectilinear tubular tip to keep the ball rotatably on a ball seat by means of a crimped or deformed forward end to the tip, the ball seat being inserted into the tubular tip. This type of ball point pen is disclosed in U.S.A. Patent 4,139,313 to Hori. This structure provides an advantage in that the rectilinear tubular tip can be readily manufactured, but, on the other hand, a disadvantage in that the ink passage between the ball and ink reservoir is long.

Further, when the ball to be applied is very small as described above, the tubular tip, ink feeding elements, such as, the ball seat and ink passage fdrmedbetween the tip and the ball seat, should be very small, resulting in a shortage in the ink supplied to the ball. Besides the above, the rectilinear tubular tip, which has an inner diameter substantially equal to that of the ball, is bent at its one end toward an axis thereof for securing the ball and then barrel-finished at the other end of the tip. However, the barrel-finishing is likely to produce burrs and fins at the rear end of the tip, the burs and fins being obstacle to assembly of the ball and the ink feeding ball seat member.

Accordingly, an additional process of deburring and definning is needed.

An object of the present invention is to provide an improved socket structure for the writing ball of a bail point pen.

An object of an embodiment of the present invention, is to provide a socket for the writing ball of the ball point pen, which permits adjustment of ink to be supplied to the ball.

According to the present invention, there is provided a socket for holding a writing ball of a ball point pen comprising: an outer tubular member fixed relative to a casing of the ball point pen, an inner tubular member inserted into said outer tubular member, said inner tubular member having a funnel shaped portion at one end thereof, a ball seat member of substantially rod shape, said ball seat member being located in and fixed to said inner tubular member, said ball seat member having ink conducting channels, and a writing ball rotatably supported at one end of said ball seat member by the other end of said inner tubular member.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of a writing tip portion of a ball point pen barrel into which a socket according to an embodiment of the present invention is inserted and located in position.

Figure 2 is a sectional view taken along Il-Il of Figure 1.

Figure 3 is a sectional view taken along Ill-Ill of Figure 1.

Figure 4 is a sectional view taken along IV-IV of Figure 1.

Figures 5, 6 and 7 are each section views of part of a modified socket according to other embodiments of the present invention.

Figure 8 to 11 are sectional views of a socket sleeve and a ball seat member, showing a relation between a circumference of the ball seat member and ink passages.

In this description, the writing end of the ball point pen barrel is considered to be the front end.

Referring to Figures 1 to 4, a sleeve 1 has a reduced inner diameter portion 5 at its forward end for rotatably holding a ball 2 and a funnel shaped portion 4 at its rear end. A rod-type ball seat member 3 is inserted into the sleeve 1 so that the ball 2 is rotatably secured on a seat 3, of the ball seat member 3 and rotatably held in position by the reduced inner diameter portion 5. The ball seat member 3 is fixed relative to the sleeve 1 by a recessed portion 14 which is formed by crimping to form a writing tip portion or socket6 of the ball point pen, generally indicated at 20. As-illustrated in Figure 1, an annular space 13 is formed between the funnel shaped portion 4 of the sleeve 1 and the circumference of the ball seat member 3. The ball seat member 3 is preferably made of suitable wear-resistance plastics materials.The sleeve 1 is preferably made of suitable metal or hard plastics material. In the illustrated embodiment, the ball seat member 3 has a number of ribs at its circumference which forms a plurality of grooves 1 7 between the inner wall of the sleeve 1 and the circumference of the ball seat member 3. The ink passages confined by the sleeve 1 are partly deformed but not closed by the aforesaid recessed portion 14, as illustrated in Figure 3.

The socket 6 is inserted into a guide tube 10 fixed to a holder 12 of a barrel 1 5 such that the rear end of the ball seat member 3 may contact a wall 8 of the holder 12. As illustrated in Figures 1 and 4, the holder 12 has substantially triangular holes as ink passages 1 The funnel shaped portion 4 of the sleeve 1 is mounted within a space 9 which is connected to the ink passages 11 of the holder 1 2. Within the holder is provided an ink feeding core 7 which is preferably made of a bundle of synthetic fibers and connected to an ink reservoir (not shown) within the barrel 1 5.

Since the sleeve 1 has a funnel shaped portion 4 at its rear end, any burs or fins which are unintentionally formed as a result of the barrelfinishing process do not become an obstacle to the assembly of the ball 2 and of the ball seat member 3. Accordingly, the additional deburring step is not needed. Besides, ink passing through the ink feeding core 7 and the ink passage 11 into the space 9 is directed through the annular space 21, which is of triangular shape in cross section, to the grooves 7 formed on the circumference of the ball seat member 3, and ink can be uniformly fed to the grooves.

In order to facilitate a more active ink feed, stronger capillary action should be obtained adjacent to the ball seat 3. To this end, the ball seat member 3 may be expanded at the position adjacent to the ball seat 3, to form smaller grooves than the grooves 17 of Figure 2. This may be readily performed, when the ball seat 3, is to be formed, by pressing the ball against the forward end of the ball seat member 3, since-the ball seat member 3 expands adjacent to the seat 3, when the pressure is applied against the ball so as to form the ball seat 3.

In the embodiment shown in Figure 1 in which the funnel shaped rear end 4 is positioned in the space- 9, the ball seat member 3, has such an elasticity that the member 3 is retracted, though slightly, when a writing pressure is applied against the ball and that the retracted member 3 returns to its normal position, when the pressure is removed. Accompanying the axial movement of the ball seat member 3 the sleeve 1 is also moved axially. When the funnel shaped end 4 is retracted, a pressure is applied to ink positioned within the funnel shaped end 4 to facilitate the ink to be fed toward the ball 2. On the other'hand, when the funnel shaped end 4 is returned or advanced to its normal position, ink is sucked from the passages 11, and a smooth and continuous ink flow can be obtained.If much more, "pumping" effect as described above is needed, the funnel shaped end 4 is preferably designed such that an outer end of the funnel shaped end 4 is frictionally and slidably engaged with an inner surface of the guide tube 10 or of the holder 12 as illustrated in Figure 5.

Figures 6 and 7 show further modifications of the sleeve 1 with funnel shaped end 4. In Figure 6, the funnel shaped end 4 contacts the wall 8 of the holder 12 so that the sleeve 1 is fixed relative to the holder 12. The guide tube has a recess at itsrear end to form a space for the funnel shaped end 4. In this structure, ink in the passages 11 is fed by surface tension at the funnel shaped end 4. In the embodiment of Figure 7, the funnel shaped end 4 is press-fitted into the guide tube 10. This structure can prevent inkfrom leading out of the pen since the end of the guide tube 10. A small air space 18 between the other part of the sleeve 1 and the guide tube 10 is to provide the user with a feeling that the pen has suitable flexibility.

The ball seat member 3, which also has a function of feeding ink toward the ball 2 by capillary action, has a core portion 3a and plurality of ribs or legs 3b extending regularly and radially form the core portion to form a number of grooves 1 7 for ink passage as illustrated in Figures 2 and 3. Figures 8 and 9 illustrate a modification of the ball seat member 3 in which the legs 3b extend regularly and radially from the core portion 3a as in the structure of Figures 2 and 3, but has a circumferential space 1 8 communicating one groove with the others. Alternatively; a plurality of ink channels 16 may be formed at regular intervals around-an outer portion of the ball seat member 3, as illustrated in Figures 10 and 11.In each case, the rear end-of the ball seat member 3 is received by the wall 8 of the holder 12, and the circumferential or outer portion of the ball seat member 3, which has an ink feeding function, is aligned with the ink feeding passages 11 of the holder 12.

As described above, the sleeve 1 and the ball seat member 3 are fixed relative to each other.

This permits a rotation of the combined structure of sleeve 1 and ball seat member 3. Accordingly, the cross section area of the ink passage 11 can be adjusted by rotating the tip portion or socket 6.

If a user wishes the opening ratio of the ink passages 11 be greater than the ratio as illustrated in Figures 8 and 10, this can be readily accomplished to produce a greater opening ratio as illustrated in Figures 9 and 11 by merely rotating the socket.

Although the present invention has been described with reference to preferred embodiment, many modifications and alterations can be made within the spirit of the invention. For example, a single spiral or radial channel may be formed in the wall 8 of the holder as the ink feeding passages 11 in place of the holes.

Claims

1. A socket for holding a writing ball of a ball point pen comprising: an outer tubular member fixed relative-to a casing of the ball point pen, an inner tubular member inserted into said outer tubular member, said inner tubular member having a funnel shaped portion at one end thereof, a ball seat member of substantially rod shape, said ball seat member being located in and fixed to said inner tubular member, said ball seat member having ink conducting channels, and a writing ball rotatably supported at one end of said ball seat member by the other end of said inner tubular member

2. A socket according to claim 1, in which said funnel shaped portion- of the inner tubular member is axially slidably engaged relative to said casing.

3. A socket according to claim 1 or 2, in which said inner tubular member is-fixed relative to the casing.

4. A socket according to any preceding claim, in which said casing has a tubular holder fixed relative to said casing, said outer tubular member being fixedly mounted within said holder, said holderhaving an ink conducting passage connected to said ink conducting channels of the ball seat member, said ball seat member being rotatable together with said inner tubular member to adjust a cross-sectional area of said ink feeding channels.

5. A socket according to any preceding claim, in which said ink conducting channels are defined between the circumferential of said ball seat member and an inner surface of said inner tubular member.

6. A socket according to any preceding claim, in which said ink conducting channels are formed at an outer portion of said ball seat member.

7. A socket according to any preceding claim, in which said funnel shaped portion defines an annular space relative to the circumference of said ball seat member.

8. A socket for holding a writing ball of a ball point pen substantially as herein described with reference to and as illustrated in Figures 1 to 4, with or without reference to any of Figures 5 to 11 of the accompanying drawings.