US2718051A - Method of making ball type writing instruments - Google Patents

Description

p 0, 1955 G. D. CLOUTIER 2,718,051

OD OF MAKING BALL TYPE WRITING INSTRUMENTS Filed March 50, 1946 United States Patent 2,718,051 METHOD OF MAKINGIBALLTYPE INSTRUMENTS George D. Cloutie'r, Chicago, Ill., assignor to Eversharp, -Irrct, Chicago, Ill., a corporation of Delaware Application March 30, 1 946,SerialNo. 658,521 4 Claims. 01.2%441 This invention has to do with writing instruments of the type in which a thick ink is transferred to thepaper or otherfmaterial by a small ball which :is rotatably mounted in the .tip of the instrument, .and is particularly concerned with the Way in which the socket for the ball isprepared and the ball installed therein.

The principal object of the invention is to .provide a new and .improvedmethod ofpreparing the socket and installing the 'ball, which method facilitates production, overcomes the .di fficulties experienced in connection with prior practices, and insures a uniformfit in which the ball will always rotate 'freely with .just the right confining .pressure and ink clearance.

While the foregoing statements are indicative in a general'wayo'f'the nature o'f the-invention other more specific objects ahd advantages will be apparent to those skilled in the art upon afull understanding of the new method.

ln the accompanying drawing:

Fig. l is a greatly enlargedlongitudinal section through the tip only .of a ballzpen, showing the writing ball as finally fitted within the tip in accordance with the present invention;

Fig. -2 is Ia still further enlargedlon'gitudinal section through the front end of the tip,-after the reanportion of 'thesocket'has been preliminarily-shaped and before the front edge of the socket has been constricted;

Fig.3 is-an end view of the socket, in' the condition of v the same shown in Fig.2;

Fig. 4 is a view'of the ball which is'used as the forming element in imparting the finished sh'a'p'e to the s'ocket;

Fig. 5 corresponds with Fig. 2 but shows the socket after the forming ball has been pressed therein, the front edge of the' s'ocket closedoVer-the-balL' aiid the ball-forced out past the constricted lip;

Fig. 6 illustrates the final writing ball being snapped into the finished socket past the constricted lip; and

Fig. 7 illustrates the ball installed, with the tip in condition for writing, this view being an enlargement of a portion of Fig. 1.

The particular tip structure used herein in illustrating the invention is similar to the one shown in my earlier filed application Serial No. 606,079, now Patent No. 2,428,960, granted October 14, 1947, but it will of course be appreciated that the new method is not limited in its application to any particular design of tip structure.

As will be observed in the drawing, the finished tip structure shown in Pig. 1 and Fig. 7 consists of a hollow metal member 10 which tapers forwardly to apoint and is provided in its front end with a small socket 11 in which a ball 12 is rotatably mounted. The rear portion 13 of the socket 11 is spherical and conforms with the shape of the ball 12. This spherical portion 13 is connected at its center with a still smaller ink feeding duct 14. Forwardly of the portion 13 the socket is characterized by a generally cylindrical intermediate portion 15, which portion extends forwardly from a narrow annular shoulder 16 at the front edge of the spherical portion 13 to a slightly constricted annular lip 17 at the front edge 2,718,051 Patented Sept. 2-0, 1955 ICC of thesocket. The sphericalportion 13 is interrupted at circumferentially spaced intervals by a plurality of radiating fissures 18, preferably three in number, which fissures connect the duct '14 behind the ball with the clearance space 19 in the socket which extends about a-portion of theball. The ball llfits Within the socket 11 in snugbut freely rotatable conformity with the spherical portion 13 and the lip 17, with some clearance at 19 betweenthe ball and the intermediate portion .of the socket.

The parts described are exceedingly small in SiZ6-Ih6 diameter of the ball '1'2,preferably being on the order of something less than .040 inch and the diameter of the 'duct 14 being only about one-half the diameter of the ball The ball is adapted to operate with ink "which is not free flowing in the sense of ordinary fountain pen ink but is instead quite thick -or viscous and Will advance .throughthe duct 14 only when drawn forwardly bysuction or forced forwardly bypressure. In writing instruments using ball tips'with thick ink suitable means are 'provided for effecting -the movement of the ink through the duct 14into the socket 11.

satisfactory results, owing to the fact that theball is likely to'be mutilated to some extent during the lip forming operation, if thelip is made sfiflicientlysnug the ball may hot-rotate freely, while if the lip is left with sufficient clearance :to permit the ball to rotate freely the hall is-likely to become dislodged after a time, and even though the ball remains inplace the flow of ink pastthe lip about thealoose ball is likely to be excessive.

In preparing the socket and installing the ball in .accordance with the present invention the socket is first given the preliminary shape-shown in Fig. 2 by means of suitable formingtools, with the rear portion of the socket approximately spherical and with the sides of the socket approximately cylindricalright up to the front edge 20 of the socket.

A forming ball 21w'hich is a duplicate of the writing bail 1T2 designed to-ultimately occupy thesocket-is then iris'er't'ed'inthe trent'end of the s'ocket'and forced against thesphericalpo'rtion 13with sufiicie'nt pressure to eliminate'a'ny burrs-or"irregularities in the sphericalportion and cause the latter to conform fully with the contacting portion of the forming ball. With this forming ball 21 still in place the straight front edge 20 of the cylindrical portion 15 of the socket is then forced inwardly about the ball to provide the closely conforming lip 17, which lip is of slightly less diameter than the ball. The formation of the lip is preferably accomplished by a coining operation, through the instrumentality of a suitably flared tool.

After the lip 17 has been formed in this manner the ball 21 used in the forming operation is forcibly ejected from the socket by means of a tool inserted through the duct 14, the lip 17 yielding resiliently to an extent sufiicient to pass the ball. The ball 21 used in the forming operation is then discarded, and a new unmutilated ball the Writing ball 12-is snapped into the socket past the yielding lip 17. The tip member 10 is then ready for assembly with the other parts of the writing instrument.

The above described method has been found to give excellent results and to overcome the lack of uniformity of fit resulting from the use of prior methods. The new method is easy to practice and is adaptable to rapid mass production.

While the forming element has been described as being a ball which is a duplicate of the final writing ball, it might also be a die having a spherical head portion in simulation of the greater part of the surface of a ball. It will also be appreciated that the tip in which the socket is formed, instead of being a separate member for screwthreaded or press-fit attachment to other rearwardly disposed parts of a pen, might be formed as an integral portion of the pen, also that the rear portion of the socket, instead of being spherical, might be conical or even fiat where it opens into the ink feeding duct and still be adaptable to the truing operation effected through the preliminary use of a forming element other than the final writing ball.

I claim:

1. The method of preparing tips for writing instruments of the ball type, which consists in preliminarily forming a socket in one end of a tubular open-ended metal tip for the reception of a writing ball, thereafter inserting in the socket a spherical forming element and applying sufficient pressure to the same to cause the socket to conform closely to the contacting surface of the forming element, exteriorly constricting the front edge of the socket about the forming element to produce a resiliently expansible retaining lip in snug conformity with the latter, forcing the forming element out of the socket by an ejecting tool inserted through the other end of the tip with sufficient pressure to cause the lip to expand resiliently to the extent necessary to permit passage of the forming element, and then finally snapping a writing ball of the same spherical dimension as the forming element into the finished socket past the lip.

2. The method of preparing tips for Writing instruments of the ball type, which consists in preliminarily form a socket in one end of a tubular open-ended metal tip for the reception of a writing ball, thereafter inserting in the socket a forming ball which is a duplicate of the writing ball to be ultimately used in the tip and applying sufficient pressure to the forming ball to cause the socket to conform closely to the contacting surface of the same, exteriorly constricting the front edge of the socket about the forming ball to produce a resiliently expansible retaining lip in snug conformity with the latter, forcing the forming ball out of the socket by an ejecting tool inserted through the other end of the tip with sufficient pressure to cause the lip to expand resiliently to the extent necessary to permit passage of the forming ball, and then finally snapping a writing ball of the same size as the forming ball into the finished socket past the lip.

3. The method of preparing tips for writing instruments of the ball type, which consists in preliminarily forming a socket in one end of a tubular open-ended metal tip for the reception of a writing ball, which socket is characterized by a generally spherical rear portion which connects at its center with an ink feeding duct and by a generally cylindrical portion which extends forwardly from the spherical portion, thereafter inserting in the socket a forming ball which is a duplicate of the writing ball to be ultimately used in the tip and applying sufficient pressure to the forming ball to cause the generally spherical portion of the socket to conform closely to the contacting surface of the forming ball, exteriorly constricting the front edge of the socket about the forming ball at a point slightly in advance of the center of the same to produce a spherical resiliently expansible retaining lip in snug conformity with the forming ball, forcing the forming ball out of the then closed socket by an ejecting tool inserted through the other end of the tip with sufficient pressure to cause the lip to expand resiliently to the extent necessary to permit passage of the forming ball, and then finally snapping a writing ball of the same size as the forming ball into the finished socket past the lip.

4. The method of making tips for ball point pens which consists in preliminarily forming a socket in one end of a tubular open-ended metal tip for the reception of a writing ball, thereafter inserting into the socket a spherical forming element and applying sufficient pressure to the same to cause at least a portion of the socket to conform closely to the contacting surface of the forming element, exteriorly constricting the front edge of the socket about the forming element in the socket to produce a resiliently expansible retaining lip in snug conformity with the forming element, withdrawing the forming element from the socket so that the retaining lip expands resiliently to the extent necessary to permit passage of the forming element, and then finally snapping into the finished socket past the lip a writing ball which will fit rotatably within the socket and which has a diameter slightly greater than that of the lip.

References Cited in the file of this patent UNITED STATES PATENTS 791,330 Dodge May 30, 1905 1,753,465 Jacques Apr. 8, 1930 1,798,738 Hoern Mar. 31, 1931 1,884,155 Ostnaes Oct. 25, 1932 2,069,153 Konkle Jan. 26, 1937 FOREIGN PATENTS 2,939 Great Britain Aug. 24, 1911 1911 772,173 France Aug. 13, 1934 364,359 Italy Oct. 31, 1938

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