US 3708234 A
A ball holder for a ball point pen is disclosed together with a die for making it, having a ball holder body with an outer circumferential tip and with a hollow ink reservoir, a ball socket integrally formed on the outer tip, a writing ball mounted rotationally within the socket having a crimped rim for retaining said ball mounted within it, its upper portion protruding therethrough, a ball seat in the socket underneath the ball, having a concave polyhedral surface with ball contacts with intermediate orifices; the ball mounted within the socket supported by the contacts; ink collecting, ink holding and ink supplying concavities between the ball and the ball seat; and a pentagonally shaped ink-feed port between the ball and the reservoir, ink supplyingly, free flowingly and contiguously connected with said ball seat.
Description (OCR text may contain errors)
1 Jan. 2, 1973  BALL HOLDER OF BALL-POINT PEN [75 Inventor: Tomomitsu Fukuda, Tokyo,Japan [73 Assignee: Pentel Kabushiki Kaisha, Tokyo.
Japan (22] Filed: Feb. 25, 1971  App]. No.: 118,929
 Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 394,866 6/1965 Switzerland 401/216 Primary Examiner-Lawrence Charles Attorney-Otto John Munz [5 7] ABSTRACT A ball holder for a ball point pen is disclosed together with a die for making it, having a ball holder body with an outer circumferential tip and with a hollow ink reservoir, a ball socket integrally formed on the outer tip, a writing ball mounted rotationally within the socket having a crimped rim for retaining said ball mounted within it, its upper portion protruding therethrough, a ball seat in the socket underneath the ball, having a concave polyhedral surface with ball contacts with intermediate orifices; the ball mounted within the socket supported by the contacts; ink collecting, ink holding and ink supplying concavities between the ball and the ball seat; and a pentagonally shaped ink-feed port between the ball and the reservoir, ink supplyingly, free flowingly and contiguously connected with said ball seat.
9 Claims, 10 Drawing Figures PATENTEDJAR 2 I975 SHEEI 1 BF 3 I NVI-INTOR:
TOMOMITSU FUKUDA PATENTEDJAI 2 I975 3.708.234
sum 2 UF 3 INVENTOR:
TOMOMITSU FUKUDA BY PATENTEDJMI 21915 3.708 234 SHEET 3 OF 3 BALL HOLDER OF BALL-POINT PEN FIELD OF TH E INVENTION DESCRIPTION OF PRIOR ART In known ball-point pens, the ball holder in each case has a concave spherical surface constituting a socket which holds and supports the writing ball, and ink is supplied to the ball through an ink-feed channel of starshaped or serrated-periphery cross section. An ink-feed system of this character, however, is disadvantageous in that the ink-feed channel of star-shaped cross section is subject to clogging, which gives rise to a directivity in the ink outflow, that is, the ink outflow is not uniform for all directions of writing, whereby irregularities occurs in writing. Particularly in a ball-point pen wherein a water-soluble ink is used, the ink does not adhere uniformly to the ball because of the lack of stickiness of the ink, whereby skipping or thinning of written lines occurs, and writing becomes difficult. Furthermore, when foreign matter infiltrates into the ball holding socket, the ink flowpath becomes clogged, and the flow of ink is obstructed.
SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above described difficulties encountered in the prior ball-point pens by providing a ball holder in a ball-point pen of novel design.
According to the present invention, briefly summarized, there is provided a ball holder of a ball-point pen comprising a ball holder body with a hollow interior for containing ink and an outer tip, a ball socket formed at the tip and having a crimped rim to retain a ball within the socket, and a ball seat disposed within the body inward of and communicatively with the ball socket, and characterized in that the ball seat has a concave polyhedral surface for seating the ball whereby the ball is supported with point contacts, in that an ink-feed port communicates with the hollow interior of the body directly to the ball seat thereby to permit unobstructed flow of ink to the ball seat, and in that ink-collecting concavities are formed between the ball and recesses in the ball seat and function to collect ink and supply the same uniformly and in ample quantity to the entire surface of the ball.
The nature, principle, and utility ofthe invention will be more clearly apparent from the following detailed description with respect to preferred embodiments thereof when read in conjunction with the accompanying drawing, in which like parts and designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS In the drawing:
FIG. I is an enlarged fragmentary view, in longitudinal section, showing the essential parts of a specific example ofa ball holder in a ball-point pen according to the invention;)
FIG. 2 is an enlarged perspective view, with a partial cut away, showing the ball holder without the ball;
FIGS. 3 and 4 are respectively an enlarged side view and an enlarged end view of the forward end of a core pin for forming the ball holder shown in FIG. I,
FIGS. 5, 6, 7, and 8 are views similar to FIGS. 1, 2, 3, and 4 respectively and show another embodiment of the ball holder and tools according to the invention; and
FIGS. 9 and 10 are end views similar to FIGS. 4 and 8 respectively and illustrate other embodiments of forming tools for forming ink-feed ports.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. I, there is shown a ball holder 1 made of a synthetic resin and adapted to hold a ball 5 in a ball-point pen. The ball holder I at its forward extremity or outer tip has a ball clasping socket 4 with a bowl-shape interior constituting a ball seat 3 and having a concave polyhedral surface as shown in FIG. 2. The bottom of the ball seat 3 communicates contiguously with the forward end of an ink-feed port 2 communicating at its rear end with the hollow interior 12 of the ball holder 1, which interior constitutes an ink reservoir.
The various internal parts of the ball holder I described above are formed by a die-pressing process with a forming tool having a shape mating with that as indicated in FIG. 2 and shown in FIG. 3 for use as a die. This forming tool 7 has a tip 8 for forming the ink-feed port 2 of the ball holder, an inclined shoulder having a polyhedral surface 9 of a petal-like pattern shown as a pentagon base with five petals for forming the ball seat 3 of the ball holder, and a cylindrical part 10 for forming the ball clasping socket 4. Between the petal-like parts of the polyhedral surface 9, there are alternately disposed parts ofa convex, conical or spherical surface 11, whereby concavities 6 become ink-collecting. Ink holding and ink supplying cavities are formed in the internal seat surface of the ball socket 4.
The ball 5 is assembled in place by fitting it through the open end of the socket 4 and onto the ball seat 3 and crimping the rim of the socket 4 at its extremity so that it clasps the ball 5 and prevents it from dropping out.
In another embodiment of the invention illustrated in FIGS. 4, 5, and 6, the ball holder 21, of a structure similar to that of the ball holder 1 in the preceding example, has an ink-feed port 22 communicating with and interposed between the hollow interior 32 of the ball holder and a ball seat 23 contignously formed with the interior of a ball socket 24.
The various internal parts of this ball holder 21 are formed by die-pressing with a forming tool 27 of a shape mating wit that indicated in FIG. 5 and shown in FIG. 6. This core pin 27 has a tip 28 for forming the ink-feed port 22 of the ball holder 21, an inclined shoulder having a polyhedral surface 29 shown as a petal-like pattern with five petals and a pentagon base for forming the ball seat 23, and a cylindrical part 30 for forming the ball socket 24. The intersectional boundaries between adjacent planar surfaces of the polehedral ball seat 23 and the boundary between the ball seat 23 and the socket 24 are recessed and form ink-collecting, ink holding and ink supplying concavities 26.
In still an other improvement of the invention indicated in FIGS. 9 and 10, the forming tools, shown in FIGS. 3 and 4 and FlGS. 7 and 8 respectively are provided with bead-like ridges 33 and 34 at the corners of the forming tool tips. These bead-like ridges 33 and 34 form corresponding narrow grooves at the corners of the ink feed ports 2 and 22 FIGS. 1 and respectively. These narrow grooves function to impart capillary action whereby ink is always fed at a constant rate to the ball.
By the above described construction of the ball holder according to this invention, the ball 5 or 25 respectively is supported with point contact by the planar surface ofthe polyhedral surface of the ball seat 3 or 23 respectively whereby the rotation of the ball is very smooth. Furthermore, since ink-collecting ink holding and ink supplying concavities 6 or 26 respectively are formed between the ball holder 1 and the ball 5, the ink adheres uniformly and in ample quantity to the ball surface, whereby a uniform ink-flow without skipping or irregularities is attained. Still another advantage afforded by this invention is that since an inkfeed channel of narrow star-shaped cross section is avoided, malfunctioning of the pen due to causes such as ink clogging and infiltration of foreign matter is completely eliminated.
A further advantage is afforded by the narrow grooves formed at the corners of the ink-feed port 2 or 22 respectively by the bead-like ridges 33 or 34 respectively of the forming tool, whereby the ink, after passing from the hollow interior 12 or 32 respectively of the ball holder 1 to the ink-feed port 2 or 22 respectively, is drawn through the narrow grooves by capillary action and enters the ink-collecting ink holding and ink supplying concavities 6 or 26 respectively. Accordingly, a constant quantity of ink is always stored in these ink-collecting concavities, while excessive feeding of ink is avoided, and dripping of ink and blotching are prevented.
What I claim is:
l. A ball holder ofa ball point pen comprising:
a hollow elongated ball holder body;
a ball socket on one end portion of the body in the form of an enlarged-diameter axial recess for the rotatable retention of a writing ball;
an ink reservoir extending into said body;
a central port leading from the ink reservoir to the ball socket and having a port opening into the ball socket which is substantially smaller than the diameter of the ball and ball socket;
a ball seat at the bottom of the ball socket in the form of a generally tapering transition portion between the larger diameter of the ball socket and the smaller diameter of the port opening, said transi lion portion including a plurality of petal-like, an-
gularly adjacent, substantially flat contact surfaces which are oriented to form tangent planes to the writing ball, so as to present one distinct ball contact point on each contact surface, the tapering transition portion outside the port opening thus forming a peripheral succession of shallow ink channels around the ball, while presenting no ridges or other convex surface portions to the ball.
2. A ball holder as defined in claim 1, wherein: the opening of the central port has a regular polygonal outline so as to form substantially straight edges with the flat contact surfaces of the ball seat.
3. A ball holder as defined in claim 2, wherein:
the central port has a regular polygonal cross section and includes in each corner of the polygon a l0ngitudinal ink groove, the polygonal outline of the port opening including corresponding narrow lobes at its corners which are located between the flat contact surfaces of the ball seat.
4. A ball holder as defined in claim 2, wherein:
the petal-like contact surfaces of the ball seat adjoin one another in the vicinity of the port opening, a regular cone forming intermediate surface portions in the area where the contact surfaces are an' gularly spaced from one anothers.
5. A ball holder as defined in claim 2, wherein:
the petal-like contact surfaces of the ball seat adjoin one another over the entire transition portion of the ball seat in the manner of a regular polyhedron.
6. A ball holder as defined in claim 1, wherein:
the ball seat has five angularly adjoining contact surfaces so as to form a ring of ink channels around the writing ball whose smallest cross section is defined by a pentagon and an inscribed circle touching the latter at the contact points for the writing ball.
7. A ball holder as defined in claim 6, wherein:
the port opening has the outline of a regular pentagon which is concentric and parallel-sided but smaller than the pentagon defining the smallest cross section of the ink channels.
8. A ball holder as defined in claim 6, wherein:
the port opening has the outline of a regular pentagon which coincides with the pentagon defining the smallest cross section of the ink channels, the contact points for the writing ball thus being located at the edge of the port opening.
9. A ball holder as defined in claim 1, wherein:
the ball socket, ball seat, and central port are adjoining surface portions of an injection-molded, integral ball holder body of synthetic plastic material.