US2935969A

US2935969A - Fountain pen with overflow chamber situated in the front part of the fountain pen body

Info

Publication number: US2935969A
Application number: US578284A
Authority: US
Inventors: Kovacs Theodor
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-18
Filing date: 1956-04-16
Publication date: 1960-05-10
Anticipated expiration: 1977-05-10
Also published as: DE1008605B; CH341736A; GB795902A; FR1152674A

Description

May 10, 1960 T. Kovcs N FOUNTAIN PEN WITH ovERFLow CHAMBER SITUATED IN THE FRONT PART OF THE FOUNTAIN PEN BODY Filed April 1e, 195e United StatesPatent" 2,935,969" y FOUNTAIN PEN WITH. OVERFLOW CHAMBER SITUATED IN THE FRONT OE THE FOUNTAIN PEN BODY This invention relates .to'fountain pens having, an.over. flow -chamber situated" in the front part. of the fountain pen body which consists of at least one longitudinally extending capillary space of annular cross section narrowing towards the ink` reservoir and communicating .at the front with the atmosphere and at the rear through an. air passagewith the ink reservoir.

It is an object of the invention to improve the func.- tioning of the overflow chamber formed by the capillary space or spaces by specially designing said space or spaces. It is a special object of the invention to control the processes of illing, and emptying of the overow chamber more accurately than has hitherto been possible.

It is another object ofthe invention to facilitate' the assembling of the fountain pen;

Other objects of the invention concern. details which will facilitate the disassembling and reassembling for cleaning purposes of the parts essential for the proper functioningv of ther fountain pen.

The front part of a fountain pen according to the invention is shown at anY enlarged scale, and by way of example only, in the accompanying drawing in which:

Fig. 1 is a longitudinal' section of theA front part'of the fountain pen in the'plane offsymmetry, and

Figs. 2, 3 and 4v are cross sectional views taken'along the corresponding lines II-II, III-III, and IV-IVof Fig. l`. y

In the drawings, 1 designates thefont part of the hollow fountain pen body, in the rearwardly closed'frear part of which (not shown)r isplocated the-inky reservoir. The bore of the. fountain pen body is restricted at its front end 2. A tubular body 3* having ahead 4 is inserted inthe fountain .pen body. from. the: front.l so thatf onlyr its head 4 projects outsideV said: body. The shank portion 5 of the tubular body adjacent the head 4 is sealingly and` ixedly retained in the mouth of' the fountain pen body. TheV outside diameter ofthe rear end portion 6 of the tubularl bodyis byr afew ten thousandths of an inch smaller tharrthatof the shank portion 5, so that the rear end portion 6-may readily" be inserted through the mouthof the fountain-penbocly.' .The tubular body has an intermediatepertion; ofaredilced diameter extending `between the shank portion 5 and the end portion 6. A short section 7 of the tubular body adjacent the end portion 6 has a diameter about .00S in. (0.2 mm.) smaller than that of the end portion 6. The intermediate portion of the tubular body extending between the section 7 and the shank portion 5 is of a more reduced diameter and tapers from the section 7 towards the shank portion 5 following the shape of a hyperbola or of a hyperbolashaped curve. In the bore of the fountain pen body is inserted fro-m the rear a sleeve 9 which with its rear end 10 is xedly retained in the bore of the fountain pen body. The sleeve 9 with its front end embraces the shank portion 5 and is thereby centered at the front. Between its rear end portion 10 and its front end, the sleeve is of reduced outside diameter. A short section 11 of the sleeve adjacent the rear end portion 10 has 2,935,969 Patented. May 10, 1960 2. an outside diameter about` .008 in. (0.2 mm.) smaller than that of the end portion 10. The part' of the sleeve extending from section 11 to theV front end thereof is of morer reduced diameter; The sleeve tapers in" longitudinall cross sectiontowards the front following the form of a hyperbola or of' a hyperbola-like curve. The section 7 of the tubular bo'dy 3 forms withinthe bore of sleeve 9 a space 12 of annular cross section which is s'o narrow that,A during writing, it retains the quantity `of inle previously received therein. The capillary space formed within the bore of sleeve' 9 by the hyperboloid surface 8 of the tubular body 3 narrows in longitudinal cross section towardsthe ink reservoir, following the form of a hyperbola or of a hyperbola-like curve, and is so di'rnensionedA as tobe capable of receiving excess ink and giving it olf again. The section 11 of sleeve 9 forms within thev bore of the fountain pen body a -space 14 correspondingtozthevnarrow space 12,*while'the hyperboloid surface 15 of sleeve 9 forms an outer space 16 corresponding tothe inner capillary space 13. Both

spaces

13 and 16 constitute the overow chamber.

The tubular body 3v is provided withv a through` bore thev inner diameter of which is approximately .02 in. (0.5 mm.) greaterV within the head 4 than behind said head. Insertedv from. the. front into the boreV of the tubular. body isa pin.17l having. a thickenedfrontr portion 18. which fits into the front. partoff the bore of the tubu-V lar. body andv is provided with. a recessadaptedv to receive the pen 19.' The reduced rear portion of the pin has an outside diameter which is by about .004 in. (0I-l' mm.) smallerthan the diameter ofJ the surrounding.bore,.where by a narrow space 20-of annular cross section fadapte'd to conduct ink therethrough is formed aroundithe reduced rear portion of the pin.

The head 4 of the tubular body 3 covers the penalmost up to its point. A11-axial vent passage ZInarrowing towards the rear and extending upwardly into vthe region ofthe front portion of the

capillary spaces

13, 16 i'sY provided in the front part of pin 17. In itswider front. part the vent passageZl is provided with threads, while at-its rear end, it communicates with spaceA 13 through a narrow transverse bore 22 of pin 1.7. and through a further transverse bore 23 formed in theitubu l'ar body 3. The sleeve 9 surroundingthe tubular body is provided with three transverse bores 24 equally spaced aroundv its. circumference,tone of said'bores beingaligned coaxially with the aligned transverse bores 22 and 231 The tubular body 3 and the sleeve 9 are each provided withl sets lof three longitudinal grooves 25 o and 26. re.- spectively, equally spaced around their circumference. One. of the longitudinal grooyes25 terminates at the front in the wide transverse bore 23,. while the longitudinal grooves 26 terminate in the. wide` transverse bores 24 of sleeve 9. The longitudinalgrooves areof such width that they haveV a lower capillary potential than the capillary spaces 13; `16,` whereby the surfaces '8 andf'1`5 ofthe respective bodies 3, 9 forming the

capillary spaces

13, 16 are divided into longitudinal lands. On the pen side of the fountain pen, the rear end portion 6 of the tubular body 3 and the rear end portion of sleeve 9 are provided with respective narrow

longitudinal slots

27, 28 which when wet will not allow the passage of air. An air passage 29 about .02 in. (0.5 mm.) wide and increasing in depth towards the ink reservoir, is provided in the rear end portion of the sleeve in the central plane of slot 2S. An integral ange 30 presenting a recess 31 on the side opposite the pen, is arranged on the sleeve 9 about .08 in. (2 mm.) ahead of the section 11 thereof. At the rear the longitudinal slots 25 of the tubular body terminate short of the section 7, while the longitudinal slots 26 terminate short of collar 30.

The Vspace 16 communicating with the ink reservoir' through air passage 29 narrows in cross section towards the pen side of the fountain pen, whilst the space 13 is of constant circumferential width. The space 16 has a higher capillary. potential than thetspace'13, at least in its rear part. Y f

` Fixed in the rear end of the ink conductor pin 17 is an air evacuatng tube 32 the bore 33 of which communicates with the space 16 via a short axial bore 34 of the pin, aligned, radial bores 35, 36, 37, and air passage 29, and with the atmosphere via

bores

24, 23, 22 and 21.

Therelative position of the ink conductor pin V17 inserted from the front into the tubular body 3, and of the sleeve 9 inserted from the rear into the bore of the fountain pen body, is assured by the connection of both parts with the-tubular body. The position of pin 17 is determined by a key 39 of the tubular body, while the position of the sleeve is determined by a key 38 engaging in a groove of thetubular body.

The fountain pen according to the invention functions as follows: VThe fountain'pen is lled by drawing in ink in the usual manner. During writing, the ink flows from the ink reservoir through the ink conduit 20 to the pen 19, while the replacement air normally passes through the vent passage 21, the overflow chamber, and the air passage 29, into the ink reservoir. Any excess ink that may be present flows from the ink reservoir Va the

longitudinal slots

27, 28, and the air passage 29, into the overflow chamber, in which it advances from the rear towards the front. During writing, ink is drawn from the ink reservoir via the ink conduit 20, whereby a negative pressure is created in the reservoir which prevents the excess ink in the overflow chamber from flowing back into the reservoir. After the elimination of all excess ink, replacement air will normally enter the reservoir.

The

longitudinal grooves

25, 26 assure complete lll ing of the

spaces

13, 16 forming the overllow'chamber, due to the fact that they have a lower capillary potential than the said spaces and divide the spaces into longitudinal lands from which, during the advance of the excess ink, the air may readily escape through the longitudinal grooves not covered with ink.

The longitudinally extending

capillary spaces

13, 16 taper in longitudinal cross section towards the ink reservoir following the form of a hyperbola or of a hyperbola-like curve. With a constant taper of the spaces towards the ink reservoir, the capillary potential in said v spaces is irregular, being lower in the region corresponding approximately to the mediumheight of said spaces, than in the regions above and below thereof. This disadvantage s eliminated by the novel design of said spaces according to the invention, and the functioning of the overflow chamber is substantially improved.

The outer space 1-6 communicating with the ink reservoir through air passage 29 possesses a higher capillary potential than the inner space 13, at least in its rear portion, so that the spaces will ll and empty in the desired sequence. The complete filling and emptying of the spaces is further assisted by the fact that the outer space communicating with the reservoir through the air passage, narrows in transverse cross section towards the pen side of the fountain pen, whilst the inner space is of constant circumferential width.

The air passage 29 connecting the overflow chamber with the ink reservoir increases in depth towards the latter. Consequently, the replacement air will encounter the necessary resistance only in the narrower front part of the passage, and will periodically block the upper `part of the passage only for shortest periods of time, whereby the air passage may also act as an ink passage to the overow chamber. t

The vent passage 21 in the front portion of the ink conductor pin 17 narrows towards the rear in order to permit the ink contained in said vent passage from the filling operation may be used up without an increase in ow intensity. Threads 21 provided in the wider front of the passage retain the ink and conduct it by increased capillary effect into the narrower rear part of the bore.

I claim:

1; A fountain pen, comprising a barrel formed with an ink reservoir in the rearportion thereof, at least one sleeve arranged within the front portion of said barrel, the surfaces of said sleeve and of said barrel defining therebetween at least one longitudinally extending capillary annular overow ink storage space, said space tapering from the front to the rear, said sleeve being formed with a plurality of continuous uninterrupted longitudinal grooves cut into the outer surface thereof and extending over a length intermediate and non-contiguous the end portions of said sleeve, said grooves having a lower capii? lary potential than said overflow ink storage space and said sleeve being otherwise uncompartmented in a transverse direction.

2. A fountain pen as set forth in claim 1, said sleeve being formed with transverse bores in the front part of said sleeve, said grooves terminating at their front ends at said bores.

3. A fountain pen as set forth in claim 2, including a flange integral with said sleeve near the rear end thereof, said grooves terminating at their rear ends at said flange.

4. A fountain pen as set forth in claim 2, wherein said capillary annular space tapers substantially along a hyperbolic curve from the front toward the rear of said pen.

References Cited in the le of this patent UNITED STATES PATENTS (Addition to No. 991,812)