US 3133526 A
Description (OCR text may contain errors)
H. M. SEARS 3,133,526 WRITING INSTRUMENT WITH LARGE-CAPACITY CARTRIDGE May 19, 1964 Filed Dec. 19, 1960 In l/fl IN VEN TOR. fil erzsy M. 550.95
United States Patent 3,133,526 WRITING INSTRUMENT WITH LARGE- CAPACITY CARTRIDGE Hartley M. Sears, Laguna Beach, Calif., assignor to Hartley Pen Co., Pasadena, Calif., a corporation of California Filed Dec. 19, 1960, Ser. No. 76,614 8 Clairns. (Cl. 120-4203) This invention relates to an improvement in writing instruments and more particularly, to an improvement in writing instruments and ink cartridges of the ball-point type, employing ink reservoirs of much larger volumetric capacity than in the past. The invention also embraces a novel method of insuring continuous writing ability of ball point pens having large ink reservoirs.
It has been found in the past that in using small diameter ink reservoirs having diameters of less than about 0.1 inch and commonly used inks of viscosity of between about 9,000 and about 14,000 centipoises, the ink will not run out of an open rear end of the reservoir when the reservoir is inverted provided the forward end is closed to the atmosphere, as by the provision of a writing tip having a rotatably held ball therein and a seal of ink between the ball and its socket.
Such small diameter cartridges, while having the desirable characteristic of freedom from back leakage of ink, are limited in their ink carrying capacity and the effective writing life of the instrument is restricted.
A large diameter reservoir for the ink could not be used because the ink would flow out through the rear open end when the cartridge was placed in horizontal or inverted position. Biro, in Patent 2,258,841 used a large diameter reservoir and a writing paste which was maintained under pressure by a spring and forced toward the Writing tip by a piston which had to be mechanically advanced. Nissen, in Patent 2,192,479 applied a closely fitting, weighted scraper-follower to the surface of the body of ink to apply pressure to such ink and force it to the writing point. These expedients were not satisfactory.
The normally open-to-atmosphere rear end of an inkreservoir (of a cartridge having a writing tip at the front end) cannot be permanently sealed because during the writing operation the rotation of the ball actually pumps ink from the reservoir and a partial vacuum is generated within the upper end of the reservoir. Even a small subatmospheric pressure in the reservoir prevents such pumping action and terminates the writing ability of the instrument.
The present invention distinguishes from all prior prothe cartridge with respect to the barrel of the writing posals and provides means and methods whereby large volume reservoirs may be used (without recourse to excessively viscous inks), back leakage is prevented, a long writing life is assured, and pumping action of a ball point takes place during normal writing operation without recourse to complicated constructions.
Generally stated the method of my invention contemplates trapping a volume of air above a body of ink in a single or multi-chambered reservoir of any desired size or configuration, the lower portion of such body of ink being in communication with a writing tip and its ball. The air is so trapped by a seal which cooperates with the reservoir to prevent back-leakage when the reservoir is horizontal or inverted. The method then comprises momentarily and periodically admitting air to such trapped volume of air to maintain such volume of trapped air at a pressure sufficient to permit the ink to be withdrawn through the tip by the pumping action of the rotating Writing ball during writing. The momentary admission of air may be attained in various maneuvers, as by the action of a tipprojecting mechanism of a retractable ball point pen.
Several constructions embraced by my invention will be instrument in which such cartridge is mounted.
An object of this invention is to disclose and provide means and methods whereby ball point pen cartridges having large volume ink reservoirs may be maintained in operative condition without back leakage.
Another object is to disclose and provide an improved ink cartridge of the ball point type for use in writing instruments, such cartridge having the ability to contain a large volume of ink without back leakage and to be used in writing instrument barrels having any desired type of mechanism for projecting and retracting the writing tip,
A further object is to provide a writing instrument and a large capacity removable and replaceable ink cartridge whereby long writing life is insured and back leakage is positively prevented.
It is also an object of my invention to disclose and provide a multi-chambered ink holding reservoir characterized by freedom from back leakage and large ink carrying capacity and which may be readily employed in any writing instrument barrel.
It is another object of my invention to disclose and provide a ball-point writing instrument wherein a multichambered ink holding reservoir is normally sealed against the passage of air through the rearward ends of said chambers thereby preventing back leakage, and wherein said chambers may be selectively temporarily vented to the atmosphere to insure continued writing ability.
It is a still further object of my invention to disclose and provide an air valve mechanism suitable for use with a multi-chambered ink holding reservoir, as employed in ball-point type writing instruments, which is simply and economically manufactured and which provides an operable air seal against the passage of air therethrough except during a momentary and periodic temporary operation of the valve to an open position.
Reference will be made to the appended sheet of drawings in which:
FIG. 1 is a longitudinally transverse sectional view of a retractable ball-point type writing mechanism employing air valve means, according to my invention, and is shown with the reservoir in projected position and the air valve means closed;
FIG. 2 is a detail view of the device of FIG. 1 showing the reservoir and associated parts in retracted position, the air valve means being closed;
FIG. 3 is a detail View of the device of FIG. 1 with the reservoir and associated parts in over projected position, the air valve means shown in the temporary open position; I
FIG. 4 is a cross-sectional view of the device of FIG. 1 along the plane IV-IV; FIG. 5 is a detail view of a portion of the device of FIGS. 1-3 with an alternative air valve means, according to my invention shown in open position; and
FIG. 6 is an alternative embodiment of a writing instrument according to my invention showing an alternative construction of air valve means and a cartridge of modified form, the cartridge being in retracted position.
I have found that a large ink carrying capacity writing instrument may be attained by grouping a plurality of small diameter reservoirs together and providing a common ink feeding passageway from each to a single writing tip. Such chambers may be made by providing a multi sided insert within a large diameter reservoir to form a plurality of longitudinally extending ink holding chambers of individually small cross-sectional area. Such 3 arrangement of small diameter ink reservoirs attains the freedom from back leakage as employed by such aforementioned small diameter chambers when in an inverted position.
However, I have found that when the instrument is disposed virtually horizontally, such as when laid upon a desk or table, a head of ink is created at the junction of the ink holding chambers and the ink feeding passageway due to the relationship of the chambers, one or more being then vertically higher than a companion chamber (when the instrument is horizontal). When such a head of ink is effected, the ink tends to run from the higher disposed chambers to the lower chambers causing ink to leak out the lower chambers associated air vent. The sealing effect of the writing tip (due to the ink seal between the ball and its socket) to the atmosphere is generally eliminated when the pen is horizontal, since the higher chambers are vented to the atmosphere at their rearward ends as is the lower, and the pressures on the ink columns due to atmospheric pressure are balanced, leaving the pressure of the head of ink created thereby to force ink out of a lower chamber.
Generally stated, the reservoir of the embodiments of FIGS. 1 through 4 is provided with a multi-sided insert having a tapering cross-section from a thin forward portion to a thick, enlarged, rearward portion which serves both to reduce the rear openings of the ink chambers and to form a valve seat with the annular end surface of the reservoir. The valve seat thus formed may be flat, concave or convex, as desired, depending on the form of valve means employed.
A rod-like extension of the insert extends rearwardly of the reservoir from the insert and serves as a guide and support for a sealing disk. Such disk is a resilient valve member biased toward the valve seat and normally seals the chambers from the passage of air thereinto by sealing contact with the valve seat. The valve means further includes a stop, as an annular ledge for instance, on the interior of the barrel against which the resilient valve member may abut on forward movement of the reservoir. The valve means is associated with the retraction mechanism and actuated by its operation on the reservoir, in that forward movement of the reservoir caused by either or both retraction and projection operations of the mechanism, causes the resilient valve means to abut against the stop, eparating it from the valve seat on the reservoir against its bias and thereby temporarily opening the chamber to the atmosphere allowing the admission of air. During normal every day use of such a writing instrument, I have found that the retraction mechanism is actuated sufiiciently often to maintain normal atmospheric conditions within the chambers, allowing the instrument to continue to write properly and without the annoyance of back leakage. Under extended writing conditions, the instrument may be maintained in continuing operation by simply actuating the retraction mechanism occasionally during writing.
An exemplary embodiment of a writing instrument (and cartridge) employing the improvements therein according to my invention will now be described in detail.
The writing instrument shown in FIG. 1 includes a two section barrel, a forward barrel portion 10 and a rearward portion 11. An ink carrying reservoir 20 is disposed generally within the forward portion 10 and a retraction mechanism, indicated generally at 30, is disposed within the rearward portion 11. An air valve means, indicated generally at 40, is provided to normally seal the rearward end of the reservoir 20 and is adapted to selectively open the rearward end of the reservoir to the atmosphere upon actuation of the retraction mechanism.
Forward barrel portion 10 is generally cylindrical with a threaded, open rear end 12 which in turn has an annular rear end surface 13. Portion 10 is tapered toward its ported front end or nose portion 14 which is provided with an internal spring seat 15. A compression spring 16, seated on the spring seat 15, biases reservoir 20 rearwardly away from the nose portion 14.
Reservoir 20 is a generally cylindrical large diameter tubular container having an open rear end, with an annular rear end surface 21, and a forward nose section or ink feeding passageway 22. Passageway 22 is of reduced cross-sectional area compared to that of reservoir 20. A multi-sided insert 23, having radial sides or wings extending from a central column, is longitudinally disposed within the reservoir 20, as by being press fitted thereinto, thereby forming a plurality of longitudinally extending ink holding chambers of relatively small cross-sectional area (say about 0.01 sq. inch or less). Each of the sides or wings of the insert may decrease in thickness longitudinally from top to bottom. These chambers are filled with ink (a viscosity of between about 9,000 and about 14,000 centipoise is generally used) which may flow through the restricted openings 24, between the forward end of insert 23 and reservoir 20, into the common ink feeding passageway 22. A writing tip 25, having a rotatably held ball 26 mounted in a socket therein, is in ink feeding communication with the passageway 22 and therefore, each of the chambers such that the ball 26 may make an ink trace upon a writing surface when rolled thereon. The reservoir 20, insert 21, writing tip 25 and ball 26 comprise a cartridge.
Air valve means, indicated generally at 40, may include a resilient valve element or sealing disk 41, and a valve seat 42. Disk 41 is biased toward the valve seat 42 which s formed by the rearward end of the reservoir 20 and insert 23. According to my invention, the insert 23 is provided with an enlarged rearward portion 43, spanning the area between adjacent radial walls or wings of insert 23, as best seen in FIG. 4, to reduce the rear openings of the ink chambers, thereby forming smaller venting openmgs, and to form a larger valve seat 42 in conjunction with the annular rear end surface 21 of reservoir 20. Enlarged portion 43 also serves to support an axial rod-like extension 44 which extends rearwardly from the insert and reservoir 20 to a point where it abuts against the push button 36 under the constant urging of spring 16.
The sealing disk 41 may comprise a lower-ported, portion of a soft rubber-like, non-reactive composition facing valve seat 42 and a thin ported resilient metallic backing plate, as shown in FIG. 1. Disk 41 is slidably mounted upon rod 44 and biased thereon into a normally closed, air tight seal upon valve seat 42 by a compression spring 45. Spring 45 is axially mounted upon the rod 44 and may be held in abutting relation against the metallic backing plate of disk 41 by a washer 46 and lock 47.
The rearward barrel portion 11, is threadably mounted upon the forward barrel portion 10 and contains a retraction mechanism, indicated at 30, of generally known nature. The retraction mechanism or project-retract mechanism may be of any desired type which has an over-project action: that shown is a modification of a mechanism described in British Patent 10,026 of 1887. The form shown includes a retainer sleeve 31, having a threaded portion 32 and a cap portion 33 which is screwed into the rear end of the barrel portion 11. Sleeve 31 retains two cam elements, upper cam 34 and lower cam 35, which may be press fitted therein. A push button 36 is centrally disposed through the sleeve and is movable therethrough in a predetermined path, as determined by the constraining action thereon of pin 37. Pin 37 is fixed in the side of button 36 and rotates button 36 as it slides along the cam surfaces of the cams 34 and 35. Starting in the re tracted position, as shown in FIG. 2, the cartridge is biased by the spring 16 into tip-retracted position bearing against the button 36. Pin 37 holds the button 36 against further rearward vertical travel by catching in the upper cam 34. Upon depression of the button 36, pin 37 travels along the cam 34 to the over projected position, shown in FIG. 3, where pin 37 rests on a lower portion of the lower cam 35. Upon release of button 36, pin 37 is caught in one of the lower notches in the upper cam 34, as shown in FIG. 1, and the button 36, and cartridge are held in tip-projected position ready for use. Further operation of the retraction mechanism causes the cartridge to pass through an over projected position, as in FIG. 3, and then to a retracted position. Thus it may be seen that the cartridge passes through an over projected position on each operation of the mechanism. Such recurring action may be employed to cause temporary opening or venting of the normally closed air tight seal of the air valve means.
The length of reservoir 30 is correlated to barrel and the travel imparted to the cartridge by mechanism 30 is such that the laterally extending lip portion of sealing disk 41 is above and out of contact with stop or end surface 13 when the cartridge is in projected position (FIG. 1) and in retracted position (FIG. 2). In both these positions the air valve means is closed, sealing the multichambered reservoir to trap a volume of air above the body of ink therein and therefore sealing the chambers against back leakage of ink therefrom. As previously noted, upon each operation of the retraction mechanism, indicated generally at 30, the reservoir 20 passes through an over projected position, as shown inFIG. 3. By providing a suitable stop element, as the integral annular stop 13 formed by the annular rear end surface of barrel portion 10 which is disposed slightly below the lower surface of disk 41 when the reservoir is in normal projected position (disk 41 overhangs the valve seat 42) the air valve may be temporarily opened by movement of reservoir 24 into a temporary and momentary over-projected position. As shown in FIG. 3, the disk 41 abuts at overhanging laterally extending portions 41' against the stop or rear end surface 13 of barrel portion 11 causing it to flex upwardly at its edges or ride up upon rod-like portion 44 against the urging of valve spring 45, when reservoir 20 passes below the stop in moving to its over-projected posi-' tion. Each of the ink holding chambers is then opened to the atmosphere (through the air space between the reservoir 20 and the forward barrel portion 10 which in turn is vented through the ported forward nose portion about the writing tip thereby permitting air to enter the cartridge and maintain the air trapped therein at a desired pressure.
The stop employed in the embodiment of FIGS. 1 through 4 is provided integrally with the forward barrel portion 10 and is a non interrupted annular surface. It could, of course, be provided as a non-integral element held to the barrel by suitable fastening means and may be of interrupted rather than continuous nature. It is desirable to obtain a relatively even opening of the valve, since each of the chambers circularly disposed about the reservoir below the valve seat 42 should be vented by operation of the retraction mechanism.
Alternative embodiments of a writing instrument and cartridge are shown in FIGS. 5 and 6. In FIG. 5, the sealing disk 141 is made of a resilient rubber-like material without a metallic backing portion. It may be further provided with a snap ring 148 which holds a central portion of the disk against the enlarged portion 43 with the spring 145 urging the outlying areas or laterally extending portions toward the valve seat surface.
As shown in FIG. 6, the insert 223 may be provided with an enlarged portion 243 forming a convex or semihemispherical valve seat 242 with the annular end surface of reservoir 20. The resilient sealing disk 241 employed in this embodiment may then have a concave lower surface to seal upon the valve seat 242 and be of a semihemispherical shape. Sealing disk 241 is biased toward the valve seat 242 due to its own configuration and the constraint thereon effected by fixing the disk 241 to the rod-like extension 44 by a suitable fastener, such as the snap ring 248.
In FIG. 6, stationary means are shown associated with the barrel to serve as a stop to momentarily move the sealing means and admit air into the reservoir 20 or cartridge. Such means as shown here, are provided in the form of a rearwardly facing shoulder 213. Laterally extending portions 241' and disk 241 overlie the rear end surface 221 of the cartridge to engage the shoulder 213. Shoulder 213 may be provided within the barrel 210 such that it operates on the sealing disk 241 to open the reservoir only on operation of the project-retract mechanism from a tip-retracted position to tip-projected position. Here, the shoulder 213 is provided within barrel 210 such that it is disposed between the normal positions assumed by the sealing disk 241 when the cartridge is in retracted and projected position. Therefore the reservoir 20 is opened to the atmosphere only upon moving the cartridge from retracted position to projected position, just prior to use, but not on retracting the cartridge after use.
The length of the cartridge may be correlated to the length of the forward barrel portion 210 such that when it is in the tip-retracted position shown, the sealing disk 241 is only slightly above the stop 213, which is also within forward portion 210.
A further modification shown in FIG. 6 is that the reservoir 20 is provided with a multi-ported insert 223 rather than the multi-sided or winged insert 23 of FIGS. 1 through 5. Here the ink-holding reservoir has one large ink holding chamber which is normally sealed from the atmosphere by an air tight seal between the sealing disk 241 and valve seat 242.
Multi-ported insert 223 has a generally cylindrical outer portion 222, an inner portion, having a centrally disposed rod member 44 and an enlarged portion 243. Openings are thereby formed between the wings allowing passage of air therethrough. A valve seat 242 is formed on the insert 223, presenting a convex surface, over the portion 243, interconnecting wings and outer portion 222. Upon operation of the retraction mechanism to project the writing tip, the sealing disk 241 is moved off of the valve seat 242 by abutting against stop 213, momentarily opening the rear end of the reservoir to the atmosphere, until the reservoir is depressed enough for the disk 241 to pass the stop 213 and flip back upon the valve seat 242. The reservoir 20 is therefore normally sealed, locking in a column of air, except upon travel past the stop 213, which only occurs during operation of the retraction mechanism from tip-retracted position to tip-projected position.
By employing the improvements as hereinbefore disclosed and described in detail, a large capacity writing instrument free from back leakage of ink may be provided. The ink holding chambers are sealed by the normally closed air valve such that the instrument will not leak under any disposition of the cartridge. Furthermore, the continuing writing of the instrument may be insured due to the continuously occurring operation of the retraction mechanism encountered in normal use which temporarily opens each of the individual chambers (where multi-chambered cartridges are used) to the atmosphere, without allowing back leakage.
It should be noted that further modifications, alterations and embodiments in addition to those herein expressly disclosed and described in detail may be employed within the scope of my invention which is defined by the following claims.
1. In a writing instrument having a multi-chambered ink holding reservoir, each chamber being individually open at one end and communicating through a common ink feeding passage with a writing tip at the other end, the provision of: a valve seat formed on said reservoir about the individually open'ends of said chambers; air valve means cooperating with said valve seat to normally seal the individually open ends of said chambers from the atmosphere when said reservoir is in either a retracted position or a normal projected writing position; and
means for opening said air valve means upon movement of said reservoir forwardly beyond said normal projected Writing position.
2. A multi-chambered writing instrument of the ball point type characterized by its large ink carrying capacity and its freedom from back leakage, comprising: a barrel open at both ends, one end being tapered to form a forward nose portion; an ink reservoir disposed within said barrel and spring biased away from said forward nose portion, said reservoir having a multi-sided insert forming a plurality of ink holding chambers therein, said chambers being individually open at a rearward end and in common communication with a single ink feeding passage at a forward end; said insert having an enlarged portion at a rearward end reducing the cross-sectional areas of said chambers at their rearward ends and providing an air valve seat, valve means at said reaward end of said reservoir including a resilient sealing element adapted to seat upon said air valve seat, said valve means being selectively movable into and out of air sealing relation with said valve seat and being closed when said reservoir is in either of a retracted position or a normal projected writing position; and means for opening said valve means by movement of said reservoir toward said forward nose portion to an over projected position.
3. In combination with a multi-chambered ink holding reservoir open to the atmosphere at one end and in ink communication with a writing tip at the other, said reservoir being for use with a writing instrument barrel having retraction mechanism therein for selectively projecting and retracting said writing tip relative to said barrel, the provision of: air valve means for providing a normally closed air tight seal of said one end open to the atmosphere and means for opening said air valve means upon each projection and retraction of said writing tip operated by movement of said reservoir into an over projected position, said air valve means being closed when said writing tip and reservoir are in either retracted or projected positions.
4. An ink cartridge provided with a writing tip for use in a Writing instrument barrel having a selectively operable project-retract mechanism in its rearward portion comprising: a hollow cartridge body for ink, said body having a rearwardly directed open end and a forwardly directed writing tip; a plurality of longitudinally extending separators within said cartridge body, said separators forming a plurality of ink receiving chambers in said cartridge body where said chambers are in common communication with said writing tip, each of said chambers having a rearwardly directed open end at said cartridge body open end; sealing means carried by said cartridge sealing said open end of said cartridge body and said chamber open ends; and means carried by said cartridge and extending rearwardly past said sealing means for abutment against a project-retract mechanism when assembled within a writing instrument barrel having such mechanism.
5. In a ball-point type writing instrument employing retraction mechanism to selectively project and retract a writing tip relative to a barrel portion of the instrument, the provision of: an ink reservoir open at a rearward end and in ink feeding communication with a writing tip at a forward end; a multi-winged insert disposed within said reservoir forming therein a plurality of Iongitudinally extending ink holding chambers individually open at said rearward end and communicating in a common conduit with said writing tip at said forward end; air valve means on said rearward end of said reservoir for providing a normally closed air tight seal of said chambers against the passage of air; and means for opening said air valve means upon each projection and retraction of said writing tip operated by movement of said reservoir into an overprojected position, said air valve means being closed when said writing tip and reservoir are in either retracted or projected positions.
6. In a ball-point type writing instrument employing retraction mechanism to selectively project and retract a writing tip relative to a barrel portion of the instrument, the provision of: an ink reservoir open at a rearward end and in ink feeding communication with a writing tip at a forward end; a multi-winged insert disposed within said reservoir forming therein a plurality of longitudinally extending ink holding chambers individually open at said rearward end and communicating in a common conduit with said writing tip at said forward end; air valve means on said rearward end of said reservoir for providing a normally closed air tight seal of said chambers against the passage of air; and means for opening said air valve means operated by projection of said reservoir beyond a normal writing position; said air valve means comprising: a valve seat formed on a rearward end of said insert, said insert having an enlarged cross-sectional area at said rearward end; a rod-like member extending rearwardly from said insert; and a resilient valve member mounted on said rod-like member and biased toward said valve seat.
7. A writing instrument as in claim 6, wherein: said means for opening said air valve means includes an annular stop within a barrel portion of said instrument, said resilient valve member abutting against said stop to temporarily open said chambers upon the projection of said reservoir beyond its normal projected writing position.
8. A writing instrument as in claim 7 wherein: said valve seat is of convex configuration and said resilient valve member is of semi-hemispherical configuration having a concave sealing face directed toward said valve seat, is axially ported and is mounted therethrough on said rod-like extension of said insert.
References Cited in the file of this patent UNITED STATES PATENTS 2,142,531 Stenersen Jan. 3, 1939 2,521,285 Dearman Sept. 5, 1950 2,557,409 Brinson June 19, 1951 2,787,249 Barlow et a1 Apr. 2, 1957 FOREIGN PATENTS 444,089 Italy Jan. 12, 1949 799,237 Great Britain Aug. 6, 1958 1,001,156 Germany Jan. 17, 1957