Ink Cartridge For Tubular Writing Pen

Abstract

The invention relates to an ink cartridge adapted to be connected to the tip of a tubular point pen, the ink reservoir of which is provided, at the end facing the tip of the tubular point pen, with a transverse wall which is adapted to be broken open on connection to the tip of the pen, and beyond which the outer wall enclosing the ink reservoir projects forward to form a connection region.

Description

BACKGROUND OF THE INVENTION

In a known ink cartridge of this kind the circular cylindrical connection region is adapted to be pushed onto a cylindrical extension at the rear end of the tip of a tubular point pen, the ink cartridge being thereby opened. The cylindrical extension has a central aperture which is in communication with the inner bore provided in a screwed-in cylinder body and containing the drop weight. At its front end the cylinder body contains the tubular writing point, and in the rear region the inner bore is connected by way of one or more radially extending apertures to an ink equalizing chamber the front end of which is in communication with the ambient air.

In such construction, however, if heating occurs, ink and possibly air will pass out of the ink reservoir of the cartridge, or out of the inner bore of the cylinder body, into the ink equalization chamber and when cooling occurs it will be drawn back into the inner bore. In addition, the air effecting the equalization of pressure as ink is consumed passes by way of the ink equalization chamber into the inner bore and ink reservoir.

In known tubular point pens the ink may dry in the ink equalization chamber, so that no further equalization of pressure through this ink equalization chamber is possible, and the tubular point pen is then no longer ready for use. Complete cleaning, which is time-consuming and tedious, is then necessary.

SUMMARY OF THE INVENTION

The present invention avoids such cleaning of the ink equalization chamber which is otherwise occasionally necessary.

With an ink cartridge of the present type this is achieved in that the connecting region is double-walled and between the two walls there is provided an ink equalization chamber open at the front and closed by the transverse wall at the rear.

Consequently, an ink equalization chamber provided in the tip of the tubular point pen, or on the outer surface of the cylinder body inserted into the said tip, is no longer used, but the ink equalization chamber is situated in the ink cartridge. When the ink cartridge is changed, a new, unsoiled ink equalization chamber is thus used on each occasion, without the cleaning of the ink equalization chamber, as previously necessary, being required.

The ink cartridge according to the invention is preferably connected to a tubular point pen tip consisting of a cylinder body which at the front merges into a tubular writing point mount and which has an inner bore which receives the drop weight with a cleaning wire and is open at the rear, the tip being characterized in that in the cylinder body there is provided an annular chamber which surrounds the inner bore and which is open at the rear and open at the front, for the purpose of receiving the connecting zone of the ink cartridge.

The ink cartridge according to the invention is thus inserted from the rear into the annular chamber of this tubular point pen tip and is held sealingly in the said annular chamber. By means of the annular chamber, which is open at the front, the front end of the ink equalization chamber provided in the transition region of the ink cartridge is in communication with the ambient air.

The ink equalization chamber in the ink cartridge preferably extends spirally, and the connection region of the ink cartridge usually has a circular cross-section.

In the connection region of the ink cartridge, which is provided with double walls, the inner of the two walls may consist of a separate inserted cylinder, on the outer surface of which there is provided a depression which forms at least part of the ink equalization chamber and which preferably extends in spiral form. The inserted cylinder may be adapted to be screwed on the front into the connection region by means of a depression provided in the inner surface of the outer of the two walls. In this way a double-walled connection region containing the ink equalization chamber can thus be produced in a very simple manner.

The transverse wall closing the ink reservoir of the ink cartridge may have a prepared breaking point, and, if the transverse wall and the inserted cylinder are in one piece, a prepared breaking point may also be provided in the transition region between the transverse wall and the inserted cylinder.

The prepared breaking point in the transverse wall serves for opening the ink reservoir on connection to the tip of the tubular point pen, and the prepared breaking point provided in the transition region between the transverse wall and the inserted cylinder serves to make a connection between the rear end of the ink equalization chamber and the ink reservoir.

In the tubular point pen tip adapted to be connected to an ink cartridge according to the invention the wall surrounding the annular chamber may be connected to the inner portion of the cylinder body by means of ribs distributed over the periphery and lying in front of the annular chamber, and these ribs may form gripping depressions between one another.

In order to secure the ink cartridge of the tubular point pen tip in a defined end position, a stop for the front edge of the connection region of an ink cartridge may be provided at the front end of the annular chamber.

Reliable opening of the ink cartridge through the breaking open of the transverse wall can be achieved in a simple manner if the axial distance between the stop and the rear end of the inner wall is greater than the axial distance between the front edge of the connection region and the transverse wall of an ink cartridge.

It is additionally pointed out that, although the cartridge according to the invention preferably serves to contain ink and is thus usually used in connection with a tubular point pen, it is also possible to fill this cartridge with a different writing liquid, for example writing ink, in which case it can then, for example, be used for a suitably constructed fountain pen for writing purposes.

The invention is more fully described hereinafter referring to the accompanying drawings, which illustrate one example of embodiment, in which:

FIG. 1 is an exploded veiw of an ink cartridge according to the invention, with the appertaining tubular point pen tip and the stem of a tubular point pen.

FIG. 2 shows on a larger scale a tip of a tubular point pen with an ink cartridge fastened on it.

Referring now more specifically to the drawings, the ink cartridge 10 shown in the drawing has an ink reservoir 12 which on the side facing the tip 14 of a tubular point pen is closed by a transverse wall 16. The outer wall 18 surrounding the ink reservoir chamber 12 extends forward beyond the transverse wall 16 into a connection region 20. This connection region 20 is made with double walls, by the insertion therein of a cylinder 22, in the outer surface of which is formed a spiral depression 24 which together with the inner surface of the wall 18 forms in the connection region 20 a spiral ink equalization chamber 26 which is open at the front 28.

For the connection of the wall 18 to the inserted cylinder 22 there is also provided in the inner surface of the wall 18 a spiral depression 30 (FIG. 2) by means of which the inserted cylinder can be screwed from the front into the connection region.

In the illustrated embodiment the transverse wall 16 and the inserted cylinder 22 are in one piece, so that after the ink reservoir 12 has been filled the cartridge 10 can be closed by screwing in the inserted cylinder. In order to allow excess air to escape while this is being done, the spiral depression 30 in the inner surface of the wall 18 is so arranged that there remains in it, between the wall 18 and the inserted cylinder 22, a free space (FIG. 2) through which the air can escape in the forward direction. The sealing closing then takes place only shortly before the inserted cylinder reaches its end position, and this sealing is effected both by the transverse wall 16, which now lies against the closed inner surface of the wall 18, and by the front portion of the connection region, in which the depression 30 in the inner surface of the wall 18 and the corresponding "projection" of the inserted cylinder 22 fit sealingly in one another.

It is possible, however, for the transverse wall and the inserted cylinder to be made separately. The transverse wall can then, for example, be made in one piece with the outer wall 18, and the ink reservoir is then filled from the rear through an opening, which is subsequently closed by means of a suitable insert.

In this case, moreover, the inserted cylinder also need not extend quite as far as the transverse wall, but a predetermined gap may be left between it and the rear edge of the inserted cylinder, this gap subsequently forming part of the ink equalization chamber. Care must then be taken that when the transverse wall is broken open a connection is made between the ink reservoir and the ink equalization chamber.

The tubular point pen tip 14 which is to be connected to the ink cartridge 10 consists of a cylinder body having an inner bore 32, which contains the drop weight 34. The cleaning wire 36 fastened to the front end of the drop weight projects into the writing tube held in its mounting in the cylinder body. A cap 38 provided with a central bore is inserted into the rear end of the inner bore 32 to secure the drop weight, and in addition to break through the transverse wall 16 of the ink cartridge 10 when the latter is placed on the tip 14 of the tubular point pen, as will be described hereinafter.

The tip 14 of the tubular point pen has an annular chamber 40 which surrounds the inner bore 32 and is separated from the latter by a partition, and which is surrounded by a corresponding outer wall 42. In front of the annular chamber this outer wall is connected by means of ribs 44 to the remainder of the cylinder body, the annular chamber being open in the front between the ribs. The regions 46 between the ribs may serve as gripping depressions.

An ink cartridge 10 can be inserted from the rear into the annular chamber 40 until its front edge lies against a stop 48 in the annular chamber. The ink cartridge has then reached its end position.

When the ink cartridge is inserted into the annular chamber the transverse wall 16 comes into contact with the rear edge of the cap 38, because the axial distance between the front edge of the connection region 20 and the transverse wall 16 is shorter than that between stops 48 and rear edge of the cap 38. The transverse wall 16 is thus pushed backwards by the rear edge of the cap 38 and a prepared breaking point 50 provided in the transverse wall, and also a prepared breaking point 52 provided in the transition region between the transverse wall 16 and the inserted cylinder 22 break open. Consequently, on the one hand the ink reservoir 12 is opened and on the other hand a connection is also made between the ink reservoir and the ink equalization chamber 26. In order to permit this communication, the cap 38 is provided, as shown in FIG. 2, with outwardly directed ribs 54 which are arranged in star form, and between which the ink can pass through from the ink reservoir to the ink equalization chamber.

When the ink cartridge 10 is in the position shown in FIG. 2, ink passes out of the ink reservoir by way of the inner bore 32 to the writing tube 56, and in addition a connection is made from the ink reservoir 12 via the ink equalization chamber 26 to the ambient air. The tubular point pen is thus ready for writing.

After all the ink in the cartridge has been used, or in the event of the ink equalization chamber becoming clogged through the drying of the ink, the relatively inexpensive ink cartridge is simply replaced, without the complicated required cleaning of the ink equalization chamber, which is otherwise necessary in conventional tubular point pens.

A holder stem 58 can be screwed from the rear in known manner on the tubular point pen tip. This holder stem may be provided in its interior with a suitable stop by which the ink cartridge can be pressed into its end position, that is to say against the stop 48, when the stem is screwed on, so that the user requires applying practically no force for the insertion of the cartridge.

Manifestly minor changes can be effected in details without departing from the spirit and scope of the invention as defined in, and limited solely by, the appended claims.

Claims

I claim:

1. In an ink cartridge for connection to the tip of a tubular point pen and having an ink reservoir therein provided at the end facing the tip of the tubular point pen, with a transverse wall which is adapted to be broken open on connection to the tubular point pen tip, with an outer wall which surrounds the ink reservoir projecting forward beyond the transverse wall so as to form a connection region, the improvement comprising:

A. said connection region being double-walled; and

B. an equalization chamber between the two walls which is open at the front and is closed at the rear by said transverse wall.

2. An ink cartridge as claimed in claim 1, wherein said ink equalization chamber extends spirally.

3. An ink cartridge as claimed in claim 2, wherein said connection region is cylindrical in cross-section.

4. An ink cartridge as claimed in claim 3, wherein the inner of the two said walls of said connection region consists of a separate inserted cylinder on the outer surfaces of which there is provided a depression forming at least a part of the ink equalization chamber.

5. An ink cartridge as claimed in claim 4, wherein said depression extends spirally, and said inserted cylinder is adapted to be screwed from the front into said connection region by means of a depression provided in the inner surface of the outer of said two walls.

6. An ink cartridge as claimed in claim 5, said transverse wall and said inserted cylinder being one piece.

7. An ink cartridge as claimed in claim 6, including a prepared breaking point in the transitional region between said transverse wall and said inserted cylinder.

8. An ink cartridge as claimed in claim 7, wherein said transverse wall has a prepared breaking point.

9. A tubular point pen tip adapted to be connected to an ink cartridge according to claim 1, comprising a cylinder body which merges at the front into a tubular writing point mount and having an inner bore open at the rear for receiving a drop weight with its cleaning wire, said cylinder body having an annular chamber which surrounds said inner bore and being open at the rear and open at the front for receiving said connection region of the ink cartridge.

10. A tubular point pen tip as claimed in claim 9, the wall surrounding said annular chamber being connected to the inner portion of the cylinder body by ribs distributed over the periphery and lying in front of said annular chamber.

11. A tubular point pen tip as claimed in claim 10, said ribs forming gripping depressions between one another.

12. A tubular point pen tip as claimed in claim 11, the front end of said annular chamber having a stop for the front edge of the connection region of the ink cartridge.

13. A tubular point pen tip as claimed in claim 12, wherein the axial distance between said stop and the rear end of the inner bore is greater than the axial distance between the front edge of said connection region and the transverse wall of the ink cartridge.