US3095859A - Writing instrument - Google Patents

Description

July 2, 1963 Filed Aug. 15, 1958 M. LEVY WRITING INSTRUMENT 2 Sheets-Sheet l BY AW fi ial/j,

ATTORN Y July 2, 1963 M. LEVY WRITING INSTRUMENT 2 Sheets-Sheet 2 Filed Aug. 15, 1958 FIG. 7

INVENTOR M O R R I S L E V Y BY Jmbfl w ATTORNEY United States Patent 3,095,859 WRITING INSTRUMENT Morris Levy, Teaneck, NJL, assignor to David Kahn, lino, gownship of North Bergen, N.J., a corporation of New ersey Filed Aug. 15, 1958, Ser. No. 755,311 14 Claims. (Cl. 126-4233) The present invention is directed to a writing instrument and an ink cartridge therefor. More particularly, the present invention is directed to a plastic ink cartridge having lateral projection means thereon defining a seat for a retract spring.

At the present time, cartridges for ball point writing instruments are made from a metallic tube having lateral projections thereon for seating the spring which forms part of the retract-project mechanism of ball point Writing instruments.

It is highly desirable to make such cartridges from plastic materials not only because of the lower cost of plastic materials as compared to metals but also because plastics may be transparent or translucent and thereby provide means for the user of the pen to determine at a glance whether there is a sufiicient supply of ink in the cartridge.

It has been discovered that a plastic cartridge of the character set forth has sufficient resiliency to cause the writing tip affixed thereto to yield slightly upon the ap plication of pressure. in the prior art pens wherein the cartridge was metal, the writing tip does not yield during writing. The yielding of the writing tip of a ball point writing instrument results in increased comfort during writing.

Prior to the present invention it has not been possible to make such plastic cartridges in a simple continuous manner. It is well known that the cheapest and most practical method of forming a plastic tube is by continuous extrusion. However, it is impossible to form on an extruded tube longitudinally spaced exterior projections during the extrusion process. Nevertheless, according to the present invention, it is possible to continuously extrude plastic material to a tube having substantially uniform internal and external dimensions and in a simple manner form lateral projecting means on the exterior of the tube to provide a seat for a spring.

According to the present invention, the ink cartridge comprises an elongated plastic tube having a ball point writing tip at one end thereof, an intermediate portion of the tube having lateral projection means defining a seat for a helical retract spring. The spring is positioned around the tube between the writing tip and the projection means. One end of the spring is seated on the projection means and the other end of the spring is seated against the barrel of the writing instrument to urge the cartridge rearwardly.

More particularly, the projection means on the tube is constituted by arcuate lateral projections with the projections defining a plane substantially parallel to the axis of the tube. The longitudinal opening through the tube has narrow outwardly tapered radial extensions in the intermediate portion, the extensions lying in the plane defined by the arcuate lateral projections. In the preferred construction, the extensions extend into the lateral projections and the wall of the intermediate portion is thickest at the extremities of the extensions.

The cartridge comprises a tough, stiif, flexible and resilient synthetic organic plastic which is preferably sufficiently transparent or translucent to render visible the ink supply contained in the tube. The preferred plastic is preferably nylon or a high ethylene polymer.

The cartridge is made by providing a plastic tube having the characteristics described herein preferably formed 3,095,859 latented July 2., 1963 by extrusion and subjecting a portion of the tube to pressure sufficient to exceed the elastic limit of the plastic but just short of the rupturing point of the plastic. The pressure is then released. Although the plastic material springs back to a certain extent, the pressure is sufiicient to cause the plastic to remain in a deformed condition.

More particularly, the pressure is applied to the plastic article or tube by means of a die, the face of said die being at an angle with respect to the direction of movement of said die. The angular positioning of the face of the die makes a sharp indentation at the point of contact with the plastic article and causes sufficient fiow of plastic to result in a substantially permanent deformation of the plastic.

In the preferred method of manufacturing the cartridge, the tube is positioned between opposed dies, the face of one die being at an angle with respect to the face of the other die. More specifically, at least one die has a generally semi-cylindrical groove in the face thereof, the face of said die being rearwardly disposed in a lateral direction from said groove at an angle to a plane perpendicular to the axis of the die. Preferably, the groove divides the face into two sections, each section being rearwardly disposed in a lateral direction from said groove at an angle to a plane perpendicular to the axis of the In utilizing the dies, the tube is positioned in the opposed grooves of the dies and pressure is applied to urge the dies toward each other. By providing that the width of the groove is less than the external diameter of the tube, the angularly disposed faces of the dies engage the wall of the tube to outwardly displace the plastic and form projections on the tube.

It has been discovered that when utilizing a tube made from a tough, stiff, flexible and resilient synthetic organic plastic such as nylon or a high ethylene polymer, the tube can be deformed by the above described method to produce the lateral projection means thereon.

The most desirable plastic to be used is a synthetic resinous high polymer of ethylene known as high density polyethylene. This high density polyethylene, also known commercially as Ziegler or Phillips high density polyethylene, is a linear, highly unbranched, highly crystalline, high density polyethylene. This preferred polyethylene is generally made by what is presently known as a low pressure method although recently there has appeared on the market high density polyethylene having the desirable characteristics but which is made by processes utilizing higher pressures.

It has been discovered that when utilizing such a synthetic plastic or resin, particularly when utilizing high density polyethylene, excellent results have been obtained when the pressure applied to the tube during deformation is approximately 2,000 pounds per square inch. However, satisfactory results can be obtained when the pressure varies between 1,500 and 3,000 pounds per square inch. When utilizing other plastic materials, the minimum pressure may be more or less than preferred with polyethylene, and the desirable pressure range may vary considerably.

Furthermore, when utilizing the preferred high density polyethylene, in order to apply the pressure in a proper manner to cause sufficient plastic flow and to result in permanent deformation of the tube wall without rupturing the plastic, the face of the die preferably forms an angle of approximately 5 with a plane perpendicular to the axis, or direction of movement, of the die. In other words, when utilizing two opposed similar dies, the opposed, or mating surfaces of the dies, define an angle of approximately 10.

For a complete understanding of the present invention,

' anism for the writing unit.

reference is made to the following description and the appended drawing.

In the drawings:

FIG. 1 is a plan view, partly in section, of the cartridge of the present invention.

FIG. 2 is a cross-section taken along the line 22 of FIG. 1.

FIG. 3' is a view of the tube positioned between opposed dies prior to the application of pressure.

FIG. 4 is a View similar to FIG. 3 showing the position of the dies and the cross-sectional shape of the tube during the application of pressure.

FIG. 5 is a front view of the die showing the preferred dimensions and angles.

FIG. 6 is a plan View of the face of the die showing the various dimensions thereof.

FIG. 7 is an elevation of a ball point writing instrument constructed in accordance with the invention with parts in section showing the writing tip in projected position.

The plastic cartridge of the present invention is constituted by an ink-carrying tube 1 in which is inserted a ball point writing tip 2. The tube has a longitudinal opening 4 therethrough and an intermediate portion having arcuate lateral projections 3 on either side thereof, said projections defining :a plane substantially parallel to the axis of the tube.

The cross-sectional shape of the intermediate portion, as shown in FIG. 2, is defined by a generally oval-shaped opening 6, the minor axis thereof, that is the smaller axis of the oval, having narrow tapered radial extensions 7 and 7 lying in the plane defined by the arcuate radial projections 3.

The major axis of the oval-shaped opening 6 is perpendicular to said plane, and the length of the major axis does not exceed the diameter of the longitudinal opening on either end 5, 5 of the intermediate portion and preferably is less than the diameter of the longitudinal opening.

The wall of the intermediate portion defining the opening is thickest at the extremities 8, 8 of the extensions 7, 7 of the minor axis.

This thick wall defines the arcuate shape of the lateral projections and is of substantially uniform thickness throughout the length of the intermediate portion. The central longitudinal section 9 of the intermediate portion is defined by straight edges 9.

The combined length of the minor axis and the extensions 7, 7' is greater than the external diameter of the tube on either end of the intermediate portion. Stated somewhat differently, the -longitudinal opening through the tube has narrow outwardly tapered radial extensions in the intermediate portion, the extensions extending into the lateral projections.

It is evident that the cartridge of the present invention has substantially uniform external and internal dimensions throughout its length except at the intermediate portion. The projection means defined by the arcuate lateral pro jections 3 extend or project beyond, the exterior wall of the tube on either side of said intermediate portion, that is, extend laterally beyond the portions of the tube immediately above and below the intermediate portion.

The projection means 3 serve as a seat for a helical spring (see FIG. 7) which is positioned around tube 1 between the seat 3 and the ball point writing tip 2. One end of spring 20 is seated on seat 3 and the other end thereof abuts a shoulder 21 at the interior of the forward end of the lower casing 22 of the barrel 23 to constantly urge the writing unit rear-wardly toward the retract position.

The cartridge of the present invention is preferably used in a writing instrument having a retract-project mech- In FIG. 7 there is illustrated one embodiment of a writing instrument in which the cartridge of the present invention may be used. The writing instrument comprises a barrel indicated generally at 23 having a lower casing 22, an upper casing 24 and an intermediate holder 25. A clip 25 may be secured to the barrel 23 in any suitable manner. Within the barrel is positioned the cartridge comprising tube *1 and a writing tip 2 in the manner described above. This cartridge is mounted in the barrel for longitudinal reciprocation within the barrel.

The upper casing 214 contains the project-retract mechanism which includes a push member 27 non-rotatably mounted for axial movement in the barrel, a rotating lug member 28 and an internal gear 29. The project-retract mechanism is more completely described and claimed in the copending application of Karl Weisser Serial No. 531,460 filed August 30, 1955, assigned to the assignee of the instant application, and the disclosure of said application is hereby incorporated by reference.

The upper end 3910f the cartridge abuts the rotating =lug member at 31. When the push member is depressed, the teeth thereof urge the lugs of the rotatable lug member 28 out of the channels of the internal gear 29 causing the rotatable member to rotate until the lugs thereon are seated on stop surfaces of the internal gear thereby maintaining the writing unit in the projected position shown in FIG. 7.

When the push member 27 is again depressed, the lugs of the rotatable lug member are removed from the stop surfaces of the internal gear causing the lugs to enter channels of the internal gear and to be urged upwardly as a result of the pressure of the spring 24 against projection means 3 which in turn urges the upper end 30 of the cartridge against surface 31 of the rotatable lug member to seat the rotatable member in the retract position. This operation is described in detail in the above mentioned copending application.

For the purpose of the present invention, it is only necessary to consider that when the writing unit is in the projected position shown in FIG. 7, the upper end 36 of thecartridge remains abutting a surface 31 fixed against axial movement with respect to the barrel. In other words, the upper end of the cartridge is seated against the retract-project means to prevent rearward axial move ment of the upper end of the cartridge when the writing tip is projected through the forward end of the barrel. It is apparent that when the writing unit is in this position, and the writing instrument is being used, it would be impossible for the ball point writing tip to yield during writing if the cartridge were made of rigid metal material in the manner of the prior art cartridges.

However, when the cartridge is made from a plastic material as herein described, when axial pressure is applied to the ball point writing tip, the cartridge will yield or bend in a direction transverse to the axis of the writing instrument. This direction is shown in FIG. 7 by arrow 32.

In other words, the plastic material utilized in the cartridge of the present invention is sur'liciently rigid axially to maintain the writing tip projected from the barrel but is sufficiently yieldable laterally to permit the writing tip to be slightly urged rearwardly during writing. This construction gives the pen, during writing, a somewhat springy feel somewhat analogous to that of standard pens having flexible writing nibs. The cartridge is preferably sufficiently transparent or translucent to indicate the level of the ink 32 contained therein.

The projection means on the intermediate portion is preferably formed by an apparatus, diagrammatically illustrated in FIGS. 3 and 4. The tube 1, having generally uniform internal and external diameters, and preferably roduced by extrusion, is positioned between opposed dies 10 and 10. The dies encompass the intermediate portion of the tube 1.

Pressure is applied to urge dies 10 and liltoward each other, the pressure being sufliciently great to exceed the elastic limit of the plastic, but insufiifiicient to rupture or tear the plastic. At the end of their travel, the dies are positioned as shown in FIG. 4 and the intermediate portion of the tube 1 is deformed as shown in the same figure. At this time, the opening 6 in the intermediate portion is generally oval-shaped, the minor axis having substantially no tapered radial extensions.

The pressure which urged the dies together is now released and as a result of the spring-back of the plastic which constitutes tube 1, the opening 6 defines the shape shown on FIG. 2. In other words, when the pressure is released, there is provided the above described tapered radial extensions 7 and 7' in the minor axis of opening 6.

As can be seen from the drawings, the face of each die is defined by sections 12 and 12' which are separated by a groove 11. The sections 12 and 12 are rearwardly disposed in a lateral direction from the groove 11 to define an angle 14 with reference to a plane 15 perpendicular to the axis of the die. It is evident that these face sections 12 and 12' define an angle with respect to the respective sections of the other die.

As has been pointed out above, the plastic tube comprises a tough, stiff, flexible and resilient organic plastic, preferably nylon or a high ethylene polymer. The most desirable and preferred plastic is a snythetic resinous high polymer of ethylene known as high density polyethylene. As hereinafter further described, when utilizing such a plastic, the angles and radii of the dies are of special significance in order to properly deform the plastic in such a manner that the resultant deformation maintains its dimensions after the removal of pressure. The plastic materials utilized have a great deal of spring-back and, therefore, it is extremely difficult to provide the plastic with relatively permanent deformations.

It has been found that by using the dimensions and radii as herein set forth, it is possible to deform the plastic sufficiently to exceed the elastic limit and thereby minimize spring-back and yet avoid tearing or rupturing the plastic. The resultant article maintains its dimensional stability even at temperatures as high as 120140 F.

The preferred dimensions when utilizing the plastics as herein described, and particularly when utilizing high density polyethylene, are illustrated in FIGS. 5 and 6. The angle 14'- defined by face section 12 and plane 15 is approximately 5 or in other words, the opposed faces of the dies define an angle of approximately Excellent results are obtained when the angle is 5, but satisfactory results can be obtained when the angle is slightly above or below 5. The angle of the die face functions not only to make a sufficiently sharp indentation at the point of contact with the tube to enable the pressure to exceed the elastic limit of the plastic, but also serves to control the width of the lateral projections.

When utilizing a tube having an external diameter of approximately .125" and an internal diameter of approximately .085", the radius of groove 11 is The depth of the groove as shown by allows 16 is .030".

In the preferred embodiment, the length of the die as shown by arrows 17 is and the width of the die as shown by arrows 18 is .250". Of course, it is evident that these last mentioned dimensions are determined by the desired length of the intermediate portion. Furthermore, as can be seen from FIG. 4, the width of the die should be at least sufficiently wide to extend beyond the lateral extremities of the lateral projections.

As pointed out above, the angle of the die face affects the width of the lateral projections. The distance of travel of the dies also affects the width of the projections. Thus, to produce a tube having a projection width dimension of .205-215 and utilizing a die face angle of 5, the dies at the end of their travel will be .020 apart. The distance of travel of the dies is predetermined by the machine and the final spacing of the dies is one factor which determines the width of the lateral projections. In other words, as pointed out above, for the desired projection width the dies will be .020 apart at the end of their travel. To increase the projection width, the dies will be brought closer together and conversely, to decrease the projection width, the dies would be set further apart.

In addition, in order to prevent the dies from severing the plastic, the edges of the grooves 13 and 13' are radially curved with best results being obtained with the radius of curvature of approximately .015. Although the radius may vary from .015" it is preferably larger rather than smaller to reduce the possibility of cutting into the plastic.

The method, therefore, comprises positioning the tube 1 in the groove 11 in opposed dies 10 and 10 and applying pressure to the dies to urge them toward each other.

These dies may be mounted in any conventional press or other device for urging the dies toward each other. When utilizing high density polyethylene, excellent results have been obtained when the pressure urging the dies together is approximately 2,000 pounds per square inch. However, satisfactory results can be obtained when the pressure varies between 1,500 and 3,000 pounds per square inch. When other plastic materials are used, the minimum pressure may be more or less and the pressure range may vary considerably. However, in any case the pressure must be at least sufiicient to sufficiently deform the plastic to exceed the elastic limit of the plastic in order to result in a permanently deformed tube.

As can be seen from FIG. 4, during the application of the pressure and as a result of the angular positioning of the faces of the dies, the plastic material constituting the Wall of the tube flows outwardly to form the lateral projections. In other Words, the material of the tube is displaced outwardly to form these projections.

This method is preferably carried out in the cold or, in other words, at room temperature. However, if so desired, some heat may be utilized although the heat must obviously not be sufiiciently great to cause the flow of plastic in the absence of the application of pressure.

The two dies 10 and 10 may be mounted in a conventional press for relative axial rectilinear movement of one die with respect to the other, either or both of the dies being capable of axial reciprocation, as desired.

Alternatively, one or more dies 10 may be mounted on the periphery of an annular or circular support and one or more dies 10' may be mounted on a similar support, the two supports being positioned so that the peripheries thereof define a single plane. Either or both supports may be capable of axial rotation. The respective die faces are brought into opposition with each other by relative axial rotation of their annular supports. Pressure is applied transversely of the axis of either or both supports to urge the respective die faces toward each other to deform the plastic tube positioned therebetween.

It is evident that the dies may constitute a set of jaws on a tip assembly machine and actuated by cams, thereby eliminating .the necessity for separate operation for the projections. In other words, the projections may be formed on the same machinery which performs other functions on the tube.

The ball point writing tip 2 is secured at one end of the cartridge either before or after the projections 3 have been formed.

The preferred plastic material is high density polyethylene. This high density polyethylene is commercially available and, per se, forms no part of the present invention. This polyethylene is generally made by the process known as the Ziegler process which is a process of polymerizing polyethylene in the presence of a catalyst utilizing low pressures. The catalyst may comprise a heavy metal halide such as titanium chloride as a carrier, a soluble metal alkyl or alkyl halide as an initiator and aliphatic or aromatic hydrocarbons as vehicles. By low pressures is meant pressure of about 20 atmospheres.

These high density polyethylenes are commercially available under the trade names Super Dylan (Koppers Company, Inc); Marlex 50 (Phillips Chemical Company); Fortiflex A (Cela-nese Corporation of America); Hyfax (Hercules Powder Company). All of these high density polyethylenes are rigid or stifi materials and their stiffness in flexure, pounds per square inch (ASTM method D747-50) varies from 55,000 to 140,000, the stiffness of Super Dylan being 55,00070,000; that of Marlex 50 being 140,000; that of Fortiflex A being 140,000, and that of Hyfax 75 ,000-125,000. The density of these commercially available high density polyethylene varies from 0.945 to 0.97 gram per cc., the density of Super Dylan being between 0.95 and 0.97; Marlex being 0.9580.962; Fortiflex being 0.96; and Hyfax being 0.945.

It is apparent that, according to the preferred method of making the tube, wherein the dimensions of the tube and the distance of travel of the die are as set forth previously, when the dies are at the end of their travel, not only are the interior surfaces of the walls of the projections abutting each other but the pressure is such that the walls are compressed to a thickness less than their original thickness between the forward edges 13 and 13 of the opposed dies. Preferably the walls are compressed to a thickness approximately half their original thickness along the line of contact 9' with the dies. Of course, because of the spring-back of the plastic material, the thickness of the wall, after the dies are released, springs back slightly. However, in the final article, because of the outward flow of the material constituting the wall of the tube during deformation thereof, the wall along line 9' which is the intersection of the lateral projections and the central longitudinal section 9, is thinner than the remainder of the wall of the intermediate portion.

According to this preferred method, it is possible to produce projections having a width greater than that which could be achieved by merely flattening the tube. If the tube were merely flattened by applying pressure to collapse the tube until the interior wall surfaces abut, the maximum lateral dimension which could be achieved would be less than one-half the external circumference of the tube.

It is realized that if the tube were merely flattened by the application of pressure, upon release of the pressure the walls would spring apart and this would further reduce the maximum width which could be obtainable flattening. By providing that the width of the projection 1 means is greater than that which could be obtained by mere flattening of the tube, there is provided a relatively large secure seat for the retract spring.

This application is a continuation-in-part of my copending application Ser. No. 694,614, filed Nov. 5, 1957, now Patent No. 2,972,781, issued February 28, 1961.

I claim: a

1. An ink cartridge comprising an elongated organic plastic tube having a ball point writing tip at one end thereof, said tube having an intermediate portion including a seat for a retract spring, said seat comprising at least one lateral projection of plastic material integral with said tube, said projection defining a plane substantially parallel to the axis of said tube, said projection comprising said material laterally displaced from the wall of the intermediate portion of said tube.

2. An ink cartridge as recited in claim 1 wherein the wall of said intermediate portion is thickest in said projection.

3. An ink cartridge as recited in claim 2 wherein said plastic is selected from the group consisting of nylon and ethylene polymers.

4. An ink cartridge comprising an elongated organic plastic tube having a ball point writing tip at one end thereof, said tube having an intermediate portion includ- 1ng a seat for a retract spring, said seat comprising two opposed circumferentially spaced lateral projections of plastic material integral with said tube, said projections defining planes substantially parallel to the axis of said aid P jec i ns Comprising said material laterally displaced from the wall of the intermediate portion of said tube.

5. An ink cartridge as recited in claim 4 wherein the wall of said intermediate portion is thickest in said projections.

6. An ink cartridge as recited in claim 4 wherein the lateral distance between the outermost edge of one of said projections and the outermost edge of the other of said projections is at least equal to one-half of the external circumference of the tube on each side of said intermediate portion.

7. An ink cartridge as recited in claim 4 wherein the lateral distance between the outermost edge of one of said projections and the outermost edge of the other of said projections exceeds a dimension equal to the sum of one-half the internal circumference of the tube plus twice the thickness of the wall.

8. An ink cartridge as recited in claim 4 wherein said plastic is selected from the group consisting of nylon and ethylene polymers.

9. An ink cartridge comprising an elongated highdensity polyethylene tube having a ball point writing tip at one end thereof, said tube having an intermediate portion including a seat for a retract spring, said seat comprising two opposed circumferentially spaced lateral projections of plastic material integral with said tube,

said projections defining planes substantially parallel to the axis of said tube, the wall of said intermediate portion being thickest in said projections, the lateral distance between the outermost edge of one of said projections and the outermost edge of the other of said projections exceeding a dimension equal to the sum of one-half the internal circumference of the tube plus twice the thickness of the wall, said projections comprising said material laterally displaced from the wall of the intermediate portion of said tube. 7

10. An ink cartridge as recited in claim 9 wherein said polyethylene is sufliciently translucent to render visible the ink supply contained in said tube.

11. In a writing instrument, a barrel open at its front end, an ink cartridge reciprocably mounted in said barrel and having a ball point writing tip at its forward end adapted to be projected and retracted through the forward end of said barrel, spring means constantly urging said cartridge toward a retracted position wherein the writing tip is concealed within the barrel, means in the rear end of said barrel for projecting and retracting said writing tip, the upper end of said cartridge being seated against said means when said writing tip is projected through the forward end of said barrel to prevent rearward axial movement to said upper end of said cartridge, said cartridge comprising an organic plastic ink carrying tube having means intermediate its ends defining a seat for one end of said spring, the other end of said spring being seated against said barrel, said spring being positioned around said cartridge between said seat and said writing tip, said seat comprising two opposed circumferentially spaced lateral projections of plastic material integral with said tube, said projections defining planes substantially parallel to the axis of said tube, the wall of said intermediate portion being thickest in said projections, the lateral distance between the outermost edge of one of said projections and the outermost edge of the other of said projections exceeding a dimension equal to the sum of one-half the internal circumference of the tube plus twice the thickness of the wall, said projections comprising said material laterally displaced from the wall of the intermediate portion of said tube, said plastic tube with said tube, said projection comprising said material laterally displaced from the Wall of the intermediate portion of said tube.

13. An ink cartridge comprising an elongated organic plastic tube having a ball point Writing tip at one end thereof, said tube having an intermediate portion including a seat for a retract spring, said seat comprising at least one lateral projection of cold-worked plastic material integral with said tube, said projection comprising said material laterally displaced from the wall of the intermediate portion of said tube.

14. An ink cartridge comprising an elongated organic plastic tube having a ball point writing tip at one end thereof, said tube having an intermediate portion includ ing a seat for a retract spring, said seat comprising at least one lateral projection of cold-Worked plastic material integral with said tube, said projection defining a plane substantially parallel to the axis of said tube, said projection comprising said material laterally displaced from the wall of the intermediate portion of said tube.

References Cited in the file of this patent UNITED STATES PATENTS 352,656 Parker Nov. 16, 1886 1,727,896 Mraz Sept. 10, 1929 2,692,580 Kahn et al. Oct. 26, 1954 2,778,337 Lovejoy Jan. 22, 1957 2,800,881 Munson July 30, 1957 2,803,695 Woolley Aug. 20, 1957 FOREIGN PATENTS 641,595 Great Britain Aug. 16, 1950 1,065,288 France Jan. 6, 1954 186,165 Austria July 10, 1956

Claims (1)

1. AN INK CARTRIDGE COMPRISING AN ELONGATED ORGANIC PLASTIC TUBE HAVING A BALL POINT WRITING TIP AT ONE END THEREOF, SAID TUBE HAVING AN INTERMEDIATE PORTION INCLUDING A SEAT FOR A RETRACT SPRING, SAID SEAT COMPRISING AT

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