US2552506A

US2552506A - Writing instrument

Info

Publication number: US2552506A
Application number: US636406A
Authority: US
Inventors: John C Wahl
Original assignee: Eversharp Inc
Current assignee: Eversharp Inc
Priority date: 1945-12-21
Filing date: 1945-12-21
Publication date: 1951-05-08
Anticipated expiration: 1968-05-08

Description

May 8, 1951 J. c. WAHI.

WRITING INSTRUMENT Filed Dec. 2l, 1945 INVEN TOR. .JO/272 6." Wa/Z,

mm Smm@ i. Il

Y l mw mw. N uw Nw m w mw mmmhmwilm Ww May 8, 1951 J. c. WAHL WRITING INSTRUMENT 2 Sheets-Sheet 2 Filed Dec. 21, 1945 INVENTOR Joz 6T Wa/Z,

. www Km,

Patented May 8, 1951 WRITING INSTRUMENT John C. Wahl, Chicago, Ill., assignor to Eversharp, Inc., Chicago, Iii., a corporation of Dela- Application December 21, 1945, Serial No. 636,406

3 Claims. (Cl.

The present invention has to do with writing instruments of the type in which a thick ink; is transferred to the paper or other surface by a small ball which is rotatably mounted in the tip of the instrument.

The object of the invention is to provide, in a Writing instrument of the character described, improved means for insuring a satisfactory feed of the ink to the writing ball.

This is accomplished, according to the present invention, by retaining the supply of ink for the instrument in a reservoir and applying pressure to the ink by means of a small air pumping device associated with the reservoir.

Other more specific objects and advantages or" the invention will be apparent to those skilled in the art upon a full understanding of the construction and manner of operation of the new ink feeding means.

Three embodiments of the invention are presented herein by way of exemplication, but it will of course be appreciated that the invention is susceptible of incorporation in other structurally modified forms coming equally within the scope of the appended claims.

In the accompanying drawings:

Fig. l is an enlarged longitudinal section through a writing instrument equipped with the new ink feeding means;

Fig. 2 is a similar section, with the parts of the instrument in partially disassembled relation;

Fig. 3 is a transverse section, taken on the line 3 3 of Fig. 1;

Fig. 4 is an enlarged longitudinal section through another writing instrument, showing a somewhat different embodiment of the invention; and

Fig. 5 is an enlarged longitudinal section of another writing instrument of the capless projectable tip type, showing another embodiment of the invention.

The writing instrument shown in Figs. 1, 2 and 3 includes an elongated casing Ill which contains a cylindrical chamber II. The front end of the casing I3 tapers forwardly and is provided with a, relatively short axial bore I2. The rear end of the casing I Il is closed by a screw threaded cap I3, which can be readily removed.

An ink reservoir I4 is positioned in the chamber II of the casing. This reservoir includes an elongated outer tube I5, an elongated inner sack I6 in which the reserve supply of ink is held, and a nipple I1 to which the front ends of the tube I5 and sack I6 are secured. The nipple I1 is reduced abruptly in diameter at the front end of the tube I5, and the reduced portion I8 of the nipple projects forwardly through the bore I2` in the front end of the casing.

The nipple I1 contains a small axial bore I9 which is progressively reduced in diameter from its rear to its front end and terminated in a minute duct which opens into a socket 2|. A small ball 22-on the order of 1 mm. in diameteris rotatably mounted in the socket 2| and serves to transfer the ink from the duct 20 to the paper or other material. The ink used is preferably a thick viscous ink, as distinguished from an or dinary fountain pen ink.

The reservoir It is xedly but removably secured within the chamber II of the casing Ill by means of a forwardly tapering collet 23, which collet is interior-1y threaded at 2E and is screwed onto an exteriorly threaded section 25 of the forwardly projecting portion I8 of the nipple I1. The collet 23 abuts against the front end 26 or" the casing IEl and, upon being screwed up tightly against the end 25, serves to draw the front end 2"? of the reservoir into tightly clamped engagement with the front end 28 of the chamber II.

The rear end 23 of the tube I5 is sleeved over and xedly secured to a valve plug 33, which plug contains an axial air passage 3|. The passage 3| is normally closed at its front end by a small check ball 32 which is located Within a recess in the plug 30. The ball 32 is seated by a spring 33 which is retained in position by an apertured screw plug 3i. A collar 35 is screwed overl the rear end of the plug 30, in rearwardly projecting relation to the latter, and is provided intermediate its ends with a small laterally directed air inlet 36.

A forwardly opening cup 31 is mounted in the rear end of the collar 35, in freely slidable but substantially air-tight association with the same, and is limited in its rearward movement by an inturned rim 38 on the rear end of the collar 35. In the rearmost position of the cup 31 the inturned rim 33 engages with a small annular shoulder 39 formed in the wall of the cup. The rear end of the cup 31 projects rearwardly through an aperture in the cap I3 and the cap I3 is provided at a point opposite the air inlet 36 with an air vent 40.

A coil spring 4I is positioned within the collar 35 and is compressed between the shoulder 3&1 on the cup 31 and the rear end I2 of the plug 30. In the rearmost position of the cup 31 the air inlet 36 is uncovered by the rim of the cup and permits air to enter the space enclosed within the cup and collar. As soon as the cup 31 is pressed forwardly, by the application of finger pressure thereto, the air inlet 36 is closed off and the air trapped within the cup and the collar is forced forwardly through the passage 3l in the plug pastl the ball 32, which ball will thereupon seat and cause the air which has been forced into the inside of the tube I5 to remain therein under pressure.

The ink sack I6, which is located within the 3 tube I5, is of readily collapsible construction, and is preferably made of some Very thin limp material which 'willnot offer any appreciable resistance tobeing progressively collapsed, even under ordinary atmospheric pressure.

The increased pressure on the air surrounding the sack I6 Within the tube l5 will therefore tend to collapse the sack and cause the ink, which completely fills the same, to be urged toward the writing ball 22.

Whenever the feed of the ink to the Writing ball shows any indication of slowing down in writing it is merely necessary to increase the air pressure within the reservoir by operating the pumping device one or more times.

It will be appreciated that the ink reservoir I4 may be made either as a permanent part of the writing instrument or as .a' readily replaceable cartridge, with the Writing tip either permanently associated with the casing of the Writing instrument or the cartridge.

It will of course be understood that the front end ofthe Writing instrument is adapted to be protected, when not in use, by a removable cap (not shown) of any suitable design.

In the modication shown in Fig. 4 the ink, instead of being placed in a collapsible container, is placed in bulk Vform in the front portion of the Ytube 43 of the reservoir, completely lling the space in front of a free piston 44. The piston 44 is sealed relative to the inner wall of the tube 43 at both its front and rear ends by cup-

packings

45 and 46 which' are secured to the piston. The cup-

packings

45 and 46 may, if desired, be secured to the piston by a tubular rivet 41, with a plug 43 removably positioned in the rivet. The plug 4 3V may be removed to facilitate the filling Vof the tube 43 with ink Without entrapmentrof any air in front of the piston 44.

The writing instrument shown in Fig. is of the capless type, in which the writing tip 49 when not inV use is housed in a retracted position within a bore 5U in the front end of the casing 5|.

When an exposed operating button 52 on the rear end of the casing 5l is pressed forwardly it acts through a thrust member 53 located on the front end of a latching mechanism 54 to project the ink cartridge 55 forwardly. The cartridge 55, in moving forwardly, carries with it the writing tip 49, against the yielding resistance offered by a compressed coil spring 56.

The particular projecting and retracting mechanism shown is of the type disclosed in my copending application Serial No. 609,277, now Patent #2,483,329 dated September 27, 1949, but may be of any other suitable construction. The first push on the button 52 projects the tip 49 into the exposed position shown in dotted lines `and latches the tip in that position. The next push on the button 52 releases the latching mechanism and allows the tip to move rearwardly into its housed position.

The ink cartridge 55 includes a tubular housing 51 and a collapsible sack 58. The sack 58, which is positioned within the housing y51, contains vthe reserve supply of ink and is connected at its front end With the ink feeding duct leading to the tip 49. The thrust member 53 is provided with a forwardly extending stem 59 on which an air compressing piston 60 is mounted. The piston 69 is located Within the housing 51 near the rear end 6I of the latter, opposite a narrow relief groove 62 in the wall of the housing. In its retracted position the housing 51 is held against further rearward movement, in forwardly spaced relation to the thrust member 53, by abutment with a snap ring 63 set into the wall of the housing.

.When the thrust member 53 isV moved forwardly by operation of -the button 52, the piston 69 slides forwardly Within the housing 51 beyond the relief groove 62 4and serves to place the air about the sack 58 under pressure. The thrust member 53 then moves into engagement with the rear end 6|' of the housing 51 and moves the housing forwardly, thereby projecting the tip 49 into its exposed Writing position, with .the air in the housing 51 still held under compression by the piston 60.

..When the thrust member 53 is thereafter permitted to move rearwardly by a second push on the button 52, the housing 51 Will also move rearwardly, the tip 49 will be retracted, and the piston 60 will shirt back into a position opposite the relief groove 62, thereby allowing the builtup air pressure on the sack 58 to be released.

I claim:

1. In a Writing instrument of the type employing arotatably mounted ball as the writing tip, which tip is adapted to be protectively enclosed when the instrument is not in use, an ink receptacle which is provided at its front end with an ink feeding duct leading to the ball, means for moving the tip into an exposed Writing position, means for creating air pressure on thev ink, and exteriorly accessible means for simultaneously operating both of said two last mentioned means.

2. In a writing instrument of the type employing a rotatably mounted ball as the Writing tip, a casing, manually operable means for projecting and retracting the Writing tip relative to the front end of the casing from a protectively enclosed position to an exposed Writing position, an ink receptacle which is movable with the tip and is provided at its front end with an ink feeding duct leading to the tip, means for creating air pressure on Vthe ink, and exteriorly accessible means for simultaneously operating both said tip projecting means and said air pressure creating means.

3. In a writing instrument of the type employing a rotatably mounted ball as the writing tip, a casing, manually operable means for projecting and retra'cting the writing tip relative to the front end of the casing from a protectively enclosed position to an exposed writing position, an ink receptacle which is movable with the tip and is provided at its front end with an ink feeding duct leading to the tip, means for creating and retaining air pressure on the ink, exteriorly accessible means for simultaneously operating both said tip projecting means and said air pressure creating means, and means operable upon retraction of the tip to relieve said lair pressure.

JOHN C. WAHL.

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

f UNITED STATES PATENTS Number Name Date 1,317,472 Ashley Sept. 30, 1919 1,580,093 Upton Apr. 6, 1926 1,944,368 Primrose Jan. 23, 1934 2,107,424 Platt v Feb. 8, 1938 2,276,722 'Hillman Mar. 17, 1942 2,302,062 Schweyer Nov. 17, 1942 2,400,679 Biro May 21,V 1944 2,398,548 Moore Apr. 16, 1946 2,426,453 Huenergardt Aug. 26, 1947 ...2,444,004 .Chesler ,June 22,1948