US3580689A

US3580689A - Tubular writing head for a tubular writing pen

Info

Publication number: US3580689A
Application number: US776370A
Authority: US
Inventors: Helmuth Riepe
Original assignee: Rapidograph Inc
Current assignee: Rapidograph Inc
Priority date: 1967-11-24
Filing date: 1968-11-18
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25
Also published as: GB1178195A; FR1573782A; DE1611558A1

Abstract

The present invention is directed to a tubular writing head of a tubular writing pen, wherein the tubular writing head comprises a hollow cylindrical member having a writing tube mounted at one end thereof and the interior thereof containing a drop weight with a hair wire which extends through the tube. A loading member in the form of a mushroom-shaped member is also disposed within the interior of the hollow cylindrical member and acts upon the drop weight so as to cause the hair wire to extend through the tube even when the tubular writing pen is not held in a vertical position.

Description

United States Patent TUBULAR WRITING HEAD FOR A TUBULAR WRITING PEN 3 Claims, 1 Drawing Fig.

U.S. Cl 401/258 Int. Cl 843k 1/10 Field of Search 401/259 [5 6] References Cited UNITED STATES PATENTS 3,455,639 7/1969 Danjczek 401/259 3,466,132 9/1969 Riepe 401/259 Primary Examiner-Lawrence Charles Attorney-Burton L. Lilling ABSTRACT: The present invention is directed to a tubular writing head of a tubular writing pen, wherein the tubular writing head comprises a hollow cylindrical member having a writing tube mounted at one end thereof and the interior thereof containing a drop weight with a hair wire which extends through the tube. A loading member in the form of a mushroom-shaped member is also disposed within the interior of the hollow cylindrical member and acts upon the drop weight so as to cause the hair wire to extend through the tube even when the tubular writing pen is not held in a vertical position.

TUBULAR WRITING HEAD FOR A TUBULAR WRITING PEN BACKGROUND OF THE INVENTION The present invention relates to a writing head for tubular writing pens and comprises a cylindrical member formed with a screw thread, a preferably helical venting channel and a bore containing a drop weight, a writing tube adjoining said bore, a hair wire extending from the underside of said drop weight and a retaining means in the upper part of said cylindrical member for preventing said drop weight from falling out. The purpose of the drop weight and of the hair wire attached thereto is to regulate the flow of the ink whereby the clearing action of the moving hair wire prevents the bore in the writing tube from becoming blocked. When the end of the tubularwriting pen is applied to a surface the hair wire is automatically pushed back into the writing tube and permits ink to issue from the tube. In other words, ink will usually begin to flow from the writing tube as soon as the tubular-writing pen is applied to a surface. Thus, a tracing or writing can be produced on the surface at once.

However, since the drop weight is controlled entirely by gravity, it is possible that the hair wire will not project from the writing tube in a rest position when the tubular-writing pen is held at an angle with respect to vertical, or even horizontally, as may well be the case when drawing on an inclined or vertically placed drawing board. The ink in the tube will then form an inverted meniscus and, when the tubular-writing pen is applied to the writing surface, the ink will not make contact therewith and consequently no ink will be drawn from the pen. When this occurs the drop weight must first be moved into its proper position by shaking the pen. This is a nuisance and most inconvenient.

SUMMARY It is therefore an object of the present invention to provide a tubular-writing head of a writing pen constructed in a manner wherein the hair wire will always project from the tube thereof even when the pen is held at an angle with respect to vertical or horizontally.

In accordance with the principles ofthe present invention there is provided a tubular-writing head comprising a cylindrical member having an externally formed screw thread and venting channel and an internally formed bore, a drop weight is mounted within thebore. A writing tube adjoins the bore and a hair wire extends from the end of the drop weight nearer to the writing tube and passes through the latter. Retaining means in the part of the cylindrical member remote from the writing tube are provided for preventing the drop weight from falling out, and a loading member is mounted inside the bore for engagement with the other end of the drop weight and for applying thrust to the drop weight in the direction towards the writing tube even when the pen is held at an angle other than vertical.

The loading member preferably has the shape of a pestle or mushroom, the head of which bears against the top of the drop weight, and the center of gravity of which is located in the upper end of its stem. When the tubular writing pen is tilted, the loading member tips over in a manner such that only the edge of its head touches the drop weight. The loading member is thus capable of applying a thrust to the drop weight urging it towards the writing tube even when the pen is held at an angle with respect to vertical or horizontally, and of thus forcing the end of the hair wire out of the writing tube into a position in which the pen is immediately ready for. writing.

In order to provide for the tilting of the loading member the stem of the pestle or mushroom extends through an opening in the bottom of a cup inserted into the bore. This cup prevents the drop weight and the loading member from falling out.

The loading member may be made to occupy a defined position by limiting its angle of tilt by the arrangement between the edge of its head and the bottom of the cup.

In order to permit the head of the tubular-writing pen to be cleaned and also in order to permit a defective or unsuitable loading member to be removed, the cup which prevents the loading member from falling out may be made replaceable.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become more apparent by reference to the accompanying drawing, wherein FIG. 1 is an axial sectional view of the writing head of a tubular-writing pen constructed in accordance with preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown a tubular-writing head comprising a hollow cylindrical body 2 which is screwed into a mount 1. A chamber 9 serves as a communication path between the writing head of the tubular-writing pen and the barrel of the pen (not shown) which contains an ink reservoir. The bore 6 of the cylindrical body 2 contains a drop weight 3 disposed therewithin. A hair wire 7 is attached to the bottom side of the drop weight nearer to a writing tube 8 and extends through the writing tube 8, projecting from the outer end thereof in its normal or rest position. A mushroom-shaped loading member 4 is also located inside the bore and-disposed above the drop weight; the stem of the loading member extending through an opening 11 in a cup-shaped member 5 which serves to prevent the drop weight from falling out of the bore. When the pen is held vertically, the face of the mushroom head rests on the end face of the drop weight remote from the writing tube. However, when the pen is tilted, the loading member will also tilt into a position, such as that illustrated. This is due to the fact that the center of gravity of the loading member is located near the upper end of its stem. As will be understood from the drawing, the angle of tilt is determined by the position of the bottom of the cup. Only the edge of the mushroom head will then bear on the end face of the drop weight, and a point diametrically opposite the point of contact is retained by the bottom of the cup. The freely projecting stem of the loading member will provide leverage which will urge the drop weight away from the cup in a direction towards the writing tube. Hence, the hairwire will be urged to project from the writing tube even when the pen is held at an angle with respect to vertical or horizontally, whereby the pen will be readily accessible for writing in every position in' which it may, in actuality, be held.

In order to permit the writing head of the pen and the loading member to be replaced or cleaned, the cup 5 can be lifted out of the bore. To accomplish this, the cylindrical member 2 is unscrewed from the mount 1 and the cup, which has a flange or lip 5a resting on the-top of the cylindrical member 2, can be removed therefrom. Thus, the loading member, as well as the drop weight, are easily removable from the bore 6.

A bore 10 connects the chamber 9 with a helical venting channel 12, in order to equalize the air pressure in the ink reservoir with that of the ambient pressure.

In an alternative embodiment of the invention, the ink reservoir may be connected to the venting channel via two slots formed in the wall of the cylindrical member on opposite sides thereof. However, in this embodiment, the flange or lip 5a of the cup 5 would be formed with a discontinuous surface so as to prevent said flange from covering the slots. The flange 5a would then preferably consist of a plurality of lugs. If the number of lugs were odd, the cup could be inserted inany position since at least. one of the slots would always remain uncovered to provide communication between the ink reservoir and the venting channel.

While I have shown and described the preferred embodiment of my invention, it will be readily apparent to those skilled in the art that there are many modifications, changes and improvements which may be made therein without departing from the spirit and scope thereof as definedby the appended claims.

I claim: l. A tubularwriting head for a tubular-writing pen, said writing head comprising; a cylindrical member having an externally formed screw thread, an externally formed venting channel, and an internally formed bore, a drop weight positioned within said bore, a writing tube connected to said cylindrical member adjoining said bore, a hair wire extending from the one end of the drop weight disposed nearer to said writing tube and therethrough, retaining means in the form of a cupshaped member disposed within the bore of said cylinder remote from said writing tube for preventing said drop weight from falling out of said cylinder, means disposed in said bore for urging said drop weight in a direction towards said writing tube, said means being a substantially free-floating tiltable mushroom-shaped loading member having a head portion and a stem portion connected thereto, the face of said, head portion, being of a slightly smaller diameter than the diameter of said bore, and being disposed within said bore occupying a defined position limited by the angle of tilt of said loading member, and the center of gravity of said loading member residing in the upper end of said stem portion, said cup-shaped member having an opening in the bottom thereof and said stem portion of said loading member extending through said opening, the thrust and pressure applied to said drop weight by said loading member is in a direction towards the writing tube, and is essentially restrained when said pen is in a position other than vertical, whereby ink flow is smoothly regulated and the clearing action of said hair wire in said writing tube is facilitated so as to minimize forming an inverted meniscus in said writing tube, and said cup-shaped member prevents said drop weight and said loading member from falling outwardly from said bore.

2. A tubular writing head as claimed in claim 1, wherein said cup-shaped member is removably disposed within said bore.

3. A tubular writing head as claimed in claim 1, wherein the angle of tilt of said loading member is defined by the distance between the bottom of said cupshaped member and said other end of said drop weight.

Claims

1. A tubular-writing head for a tubular-writing pen, said writing head comprising; a cylindrical member having an externally formed screw thread, an externally formed venting channel, and an internally formed bore, a drop weight positioned within said bore, a writing tube connected to said cylindrical member adjoining said bore, a hair wire extending from the one end of the drop weight disposed nearer to said writing tube and therethrough, retaining means in the form of a cup-shaped member disposed within the bore of said cylinder remote from said writing tube for preventing said drop weight from falling out of said cylinder, means disposed in said bore for urging said drop weight in a direction towards said writing tube, said means being a substantially free-floating tiltable mushroom-shaped loading member having a head portion and a stem portion connected thereto, the face of said head portion, being of a slightly smaller diameter than the diameter of said bore, and being disposed within said bore occupying a defined position limited by the angle of tilt of said loading member, and the center of gravity of said loading member residing in the upper end of said stem portion, said cup-shaped member having an opening in the bottom thereof and said stem portion of said loading member extending through said opening, the thrust and pressure applied to said drop weight by said loading member is in a direction towards the writing tube, and is essentially restrained when said pen is in a position other than vertical, whereby ink flow is smoothly regulated and the clearing action of said hair wire in said writing tube is facilitated so as to minimize forming an inverted meniscus in said writing tube, and said cup-shaped member prevents said drop weight and said loading member from falling outwardly from said bore.

3. A tubular writing head as claimed in claim 1, wherein the angle of tilt of said loading member is defined by the distance between the bottom of said cup-shaped member and said other end of said drop weight.