US2573691A - Writing instrument - Google Patents

Description

Nov. 6, 1951 l. CHESLER 2,573,691

WRITING INSTRUMENT Filed April 14, 1945 Q1 22. 158 Fa-*- ii n 16 20 4 INVENTOR lsz'dofi ChesZefi BY r um I w ATTORNEYS 4M9 Patented Nov. 6, 1951 UNITED STAT PATENT OFFICE WRITING INSTRUMENT Isidor Chesler, Oceanport, N. J., assignor to Eagle Pencil Company, a corporation of Delaware Application April 14, 1945, Serial No. 588,382

Fig. 4 is a fragmentary cross-sectional view on a greatly enlarged scale showing the tip end of the. writing implement.

specific application shown in the drawings, is

concerned with writing implements, more particularly with what may be designated ink pencils. General objects of the invention are to provide a liquid or paste dispenser, such as a writing implement, of simple, relatively inexpensive construction, which is substantially proof against flow stoppage on the one hand, or excessive flow, flooding or waste, on the other, regardless of the temperature, humidity-or atmospheric pressure conditions under which the implement is being used, which in the writing implement embodiment requires substantially no service or replacement, but inherently includes a sumcient supply of ink to last for years, which makes a line No. 574,498, filed January 25, 1945, now issued that is substantially smudge-proof and requires no blotting, and which will write with substantially equal effectiveness, whether the writing surface is upright, or horizontal, above or below the writers hand.

The usual crimped tip edge for retaining in place the ball point of writing implements of the above type does not engage the ball at all points so that there is clearance at many points in the crimped edge through some of which air may enter the implement and through others ink escape therefrom, with fortuitous alternations of stoppage and excess ink feed, difiiculties which would be aggravated were the ink in the barrel maintained under relatively high propulsive pressure. Moreover, such crimped edge where it. does engage the ball surface acts like a scraper, so that excess ink that is not immediately conveyed to the paper is scraped oil by said edge in the rolling of the ball and is later deposited upon the paper, intermittently rendering the writing stroke heavy and ragged.

Particular objects of the invention are to provide a smooth uninterrupted and secure bearing mount for the writing ball without undue restraint to the freedom of its rotation in use, which mount is sufficiently tight to serve as a ball valve seat retaining the ink against leakage even though pressure of considerable magnitude be sustained upon the ink in the barrel, which feeds the ink continuously and uniformly to the writin point and on the one hand avoids stop page of ink flow due to the entry of air past the ball, and on the other hand the excess, flow Referring now to the drawings, a metal tip I0 is preferably threaded at l2 into a frusto-conical section II which in turn is threaded at l3 into the barrel M of the writing implement. The forward end of the tip mounts the writing ball I5 in manner to be described hereinafter. The supply of ink is stored within the barrel, from which it may flow to the writing point in any or numerous ways. Preferably, the ink is main-. tained within the barrel under sustained propul sive pressure which is resisted by the ball writing point. The propulsive pressure may be exerted and sustained upon the ink in any of various ways, as for instance by a spring according to the disclosure of my copending application Serial Patent No. 2,444,004, dated June 22, 1948, but preferably the propulsive force is the atmospheric pressure exerted upon the incompressible column of ink in the barrel, as for instance through a vent [6 in the barrel wall. The atmospheric pressure may be exerted directly upon the ink exposed to the air, within the barrel, suitable means being provided to preclude leakage of ink through the barrel vent, all as disclosed for instance in my copending application Serial No. 577,773, filed February 14, 1945, now issued Patent No. 2,504,649, issued April 18, 1950. Preferably, however, the atmospheric pressure is exerted through a flexible wall, desirably a rubber sac, which insulates and protects the ink from exposure to the air. The atmospheric pressure being exerted substantially on the entire exposed wall of the sac causes the ball to be urged firmly against its seat, thereby to preclude leakage. Particular embodiments of the latter arrangement, one of which is shown in Fig. 1 herein, are disclosed in my copending application Serial No. 573,536, filed January 19, 1945, now issued Patent 2,444,003. issued June 22, 1948.

Referring now to the writing end of the implement, the tip in is preferably of stainless or cold rolled or machine steel and the ball housed at its tip end is a solid sphere or ball l5 of hardened steel or hardened stainless steel which of ink with the escape of air from the tip, or the Fig. 3 is a transverse sectional detail view taken on line 3-3 of Fig. 2,-and r g protrudes beyond the tip. The tip has a snugly fitted area rather than line of contact with the ball in the region of the equator of the latter, that is, the bore of the tip engages the ball along a spherical segment area extending from the equator e of the ball I5 outward toward the writing pole and preferably also inward toward the confined pole of the ball. Desirably the area of contact is a spherical segment extending approximately equally at opposite sides of the equator of the ball and in the preferred embodiment the total width of that segment is approximately 20 to 25 per cent of the diameter of the ball uWhile those skilled in the art may conceive oi various ways of conforming the tip for the "corre-- lation noted with respect to the ball, a simple,

effective and reliable arrangement is to press the 1.

ball for snug fit into the end of the cylindrical tip bore, which latter for that purpose may be of diameter in the order of .001- inch smaller than v plement of the present invention an ink devoid that of the ball. Thereupon the tip is subjected to a swaging operation to cause the softer metal thereof to flow into snug engagement with the equatorial zone of the ball along the width of spherical segment above set forth, thereby to form a smooth, polished spherical segment raceway 1' in the tip,'which snugly confines the ball.

Since the spherical segment raceway 1' at its outer rim is of diameter smaller than that of the ball, the ball is confined in place so that it cannot escape from the tip. The fit is so snug as to be substantially liquid tight but yet permits the ball to roll freely in any direction within its raceway in the writing operation.

In certain of the claims, the relation between the ball and its spherical segment raceway in the 4 ball, which is altogether too-snug for use with even the finest grade of pigment ink. For, the distance between the ball and its raceway is probably in the order of a micron or less and would act to strain out the pigment from the ink. It is, therefore, desirable to use with the writing imof pigment and that has suitable dye in solution therein so that no solids are present to be strained out at the raceway and the entire ink, including the vehicle together with the color in solution therein, will be carried-by the ball, but so sparingly as to dry substantially instantly upon the writing sheet.

.The fit of the ball in its raceway is such that as long as the ball is stationary, no ink will flow orcreep from the pen. The greater the pressure transmitted through the ink, the more securely is the ball urged against its raceway which constitutes a smooth, thoroughly effective valve seat.

One particularly desirable way of accommodating the ink and exerting the sustained pressure thereon is shown in Fig. 1, which will be but briefly described here, since this construction is the subject matter of my copending application Serial No. 573,536, filed January 19, 1945, now

be removed after swaging the ball in place and formed as an integral part of the tip,separating the axial bore l l of the tip from the ball cage [8, the bore and cage being preferably of about the same diameter, the cage diameter being shown but slightly smaller than that of the bore. Thus the ball is positioned by and rolls over the center IQ of the barrier wall.

Communication from the bore I! to the ball cage 18 is preferably effected by way of a port, desirably itself a bore 20 of diameter smaller than the radius of the ball and towardone side of the ball seat, desirably as shown, nearly tan-' gentially of the tip bore l1. Desirably onl one such bore 20 is used, for reasons which will appear more fully in the description of the operation hereinafter.

. The rim 2| of the tip is preferably spaced from theball. This is accomplished preferably by fashioning a peripheral groove 22 at the interior periphery of the tip rim, the bottom of which groove 22 thus coincides with the outer edge 23 ofthe segment ball raceway r.

, The tip and the ball may be of any of a wide range of diameters, depending upon the character of writing implement or other applicator with which the same is to be used. In a desirable ink pencil embodiment, the diameter of the ball l5 may be in the order of .04 inch, the diameter of the ball cage bore I8 as above noted may be about .001 inch less and the diameter of the port 20 in the order of .015 inch. The width of the ball raceway 1 may be in the order of .008 inch. The ball point riding in a swage fitted raceissued Patent No. 2,444,003, issued June 22, 1948. According to this embodiment, there is housed within the barrel M a flexible sac 25 which may be of thin rubber and which is normally in collapsed condition, that is, it is preferably molded or electroplated about a flat mandrel or core. so that it will distend to the open position shown in Fig. 1, only when vacuum is externally applied thereto while the ink is introduced thereinto through the section II before the tip ID has been applied, all in the manner set forth in the above entitled application. As will be seen, atmospheric pressure through the vent 18 in the barrel is applied over the entire outer surface area-of the flexible sac, which pressure is effec-- tively sustained by the ball I5 in its raceway 1 so' that the port 20 and the annular space l8 below the raceway r in the ball cage 18 are completely filled with ink and no leakage will occur.

- In writing, as the ball rolls in the raceway, ink

from annular space 18 is entrained past the raceway. As ink is thus slowly consumed, the sustained atmospheric pressure upon the sac 25 maintains the port 20 and ball cage l8 filled with ink. Should any slight excess of ink be carried by the rolling ball l5 past the raceway 1', as might occur in excessively warm weather, such ink will not be scraped off at the edge of the tip, but will accumulate in the annular trough 22 Where it is held by capillarity and will be entrained inward by the rolling ball l5 to return such excess ink to the interior of the ball cage.

"'Were there any possibility for minute bubbles of air to enter therein, such bubbles would block the flow of ink until they have been again expelled. The ink being pressure-propelled through the single small port 20 and there being no other port'or passageway through which air can enter, no venting can occur, and there will be no intermittent stoppage of ink flow in the writing opera tion.

Thus there is adequate assurance that the implement will start writing instantly when applied to the paper and will write under all conditions with a continuous uninterrupted and uniform. line.

* While the invention is by no means limited to way, as disclosed, affords a passageway about th (i y p t c lar use as a Writ g i pl it lends itself particularly as a substitute for the familiar indelible or copying pencil, since it makes an ink line and its point applies sufiicient pressure to make excellent carbon copies. It is also very useful for check signatures.

The teachings of the present invention may be advantageously applied by way of example as a leak-proof dispenser, combined with an applicator for cosmetics, such as lip rouge, mascara and perfume. Such cosmetics, preferably in viscous or pasty form, would be used within the barrel in place of the ink in the implement above described, and the ball point would of course be of much larger diameter for ease of application without irritation to the delicate skin of the lips. The difiiculty of making a lipstick soft enough for ready application, and yet solid enough not to melt in warm weather, the need for pointing the stick and for providin a propel and repel case would all be obviated by the present invention.

The teachings of the present invention, when a suitably large point is used, are also applicable to paste and mucilage dispensers. The invention has the further advantage in such application, that the body of paste or mucilage is not exposed to the air, and so does not harden or form an obstructing film on the contents of the dispenser as is inherently the case with conventional sqeegee and other rubber mouth mucilage tubes that operate on the principal of admitting air into the system to help feed out the paste.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a writing implement of the type having a metal ball writing point protruding therebeyond, the combination of a metal ball, a metal tip accommodating said ball, said tip having a swage fit about opposite sides of the equator of the ball and afiording a smooth spherical segment raceway of curvature substantially equal to that of said ball for and completely encircling the ball, and extending substantially to the rim of said tip said rim having an annular trough therein adiacent the ball for surplus ink.

2. In a writing implement of the type having a metal ball writing point, the combination of a metal ball, a metal tip accommodating said ball, said tip having a swage fit about the equator of the ball and affording a smooth spherical segment raceway for the ball of curvature substantially equal to that of said ball, said tip having in the interior thereof a rigid backstop for the ball with a single port therethrough laterally of the center of said backstop and of diameter less than the radius of the ball, through which ink passes to the surfaces of the ball.

3. The combination recited in claim 2 in which the backstop is a transverse wall integral with and across the bore of the tip and in which the port is a bore therethrough of diameter less than half the diameter of said bore and nearly tangentially of said bore.

4. A writing implement comprising a vented barrel, a metal tip at the end of said barrel, a flexible sac in said barrel having one face thereof subjected to atmospheric pressure through the vent, ink charging the interior of the barrel between the other wall face of the sac and said tip, a ball writing point in the forward end of said tip, the metal from the forward rim of the tip being removed at the inner periphery thereof, to aiford an annular trough about the ball at the extremity of the tip, said tip having a sw-age fit about the equator of said ball and affording a spherical segment raceway for the ball and fitting sufiiciently tightly to restrain leakage of ink therethrough under the sustained atmospheric pressure upon the ink.

5. A writing implement comprising a vented barrel having a writing tip thereon, a flexible ink filled sac within said barrel afiixed with respect to said tip, said sac being of the normally collapsed type and being distended by its ink content, the tip having a bore therethrough, a ball lodged at the outer end of the tip, the outer rim of said tip presenting a groove along its inner periphery, with the outer part of said groove spaced from the ball and affording an annular ink trough about the ball, said tip having a swage fit about the equator of the ball, along a smooth spherical segment raceway closely embracing the ball, said fit being sufficiently tight to restrain the leakage of ink under the sustained atmospheric pressure thereon.

ISIDOR CHESLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 600,299 Werner Mar. 8, 1898 807,280 Kegrize Dec. 12, 1905 1,065,872 Johnson June 24, 1913 1,171,652 Riesberg Feb. 15, 1916 1,181,574 Crocker May 2, 1916 1,381,332 Qualmann June 14, 1921 1,485,181 Grund Feb. 26, 1924 1,527,971 Forsell Mar. 3, 1925 1,616,551 Rosenberg Feb. 8, 1927 1,980,625 La Forest Nov. 13, 1934 2,096,397 Harris Oct. 19, 1937 2,106,046 Barlow Jan. 18, 1938 2,107,424 Platt Feb. 8, 1938 2,208,588 Laforest Jan. 23, 1940 2,204,778 Sturm June 18, 1940 2,211,312 Barlow Aug. 13, 1940 2,265,055 Biro Dec. 2, 1941 2,333,451 Sussman Nov. 2, 1943 2,376,222 Barlow 1- May 15, 1945 2,390,636 Biro Dec. 11, 1945 2,444,003 Chesler June 22, 1948 2,444,004 Chesler June 22, 1948 FOREIGN PATENTS Number Country Date 366,218 Germany 1923 476,971 Great Britain 1937 564,172 Great Britain Sept. 15, 1944 564,173 Great Britain Sept. 15, 1944 OTHER REFERENCES Websters 1939 Unabridged Dictionary-page 2290, definition 76 under set, page 2292, definition under set hammer.

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