Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
1999-06-09
2002-12-03
Stafira, Michael P. (Department: 2877)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C385S147000
Reexamination Certificate
active
06488413
ABSTRACT:
BACKGROUND
The present invention is directed to systems for the injection molding of plastic parts. In particular aspects, the invention is directed to a gating system useful in the molding process for creating optical fiber ferrules.
A fiber optic ferrule is a tubular member that receives the end of an optical fiber or fibers and is then abutted against an opposing ferrule in order to precisely align the fibers so that an optical signal can be transmitted between them.
FIGS. 1 and 1A
of the drawings depict an exemplary ferrule
10
of a type that is known in the art. As shown there, the ferrule
10
has a generally cylindrical body
12
having ends
14
and
16
. The first end
14
has a reduced diameter portion
18
that is adapted to retain a sleeve (not shown) to form an abutting connection with a like ferrule.
The cylindrical body
12
also defines a pair of concentric bores
20
and
22
therewithin. The first bore
20
has a large diameter with an opening
24
at one end of the body
12
. The first bore
20
may be slightly tapered along its length. The second bore
22
has a reduced diameter with an opening
26
at the other end of the body
12
. The diameter of the second bore
22
is very small—on the order of 0.02 mm.
Ferrules are typically formed of a polymer or other plastic and are created by injection molding. In order to operate properly, ferrules must be fashioned with great precision. The allowable tolerances for these components are typically only a few microns. Therefore, the details of the molding process must be carefully controlled. Conventional injection molding processes, however, often result in uneven plastic flow patterns and high failure rates. Improved molding processes and systems are desired. Also, even with ferrules that meet specifications, the amount of discarded polymer to usable polymer is high.
SUMMARY OF THE INVENTION
The present invention describes devices and methods for the precise molding and creation of ferrules or other plastic parts. In the exemplary embodiment described herein, a molded plastic part is formed that yields four ferrules. The plastic part has a central hub from which four arms extend, each having a ferrule-carrying portion.
A mold is described for molding the plastic part. The mold has a pair of interengageable halves that mate to form a novel series of runners and gates for formation of the plastic part. When molten plastic is injected into the mold, the runners and gates provide for improved plastic flow to form the ferrule-carrying portions of the part. In the described embodiment, molten plastic is flowed from a central chamber through four substantially cylindrical channels. From each channel, the molten plastic then flows into a fan-shaped gate, a ring gate and a parabolic gate. The molten plastic is temporarily accumulated by the gating system and then flowed into a ferrule molding chamber in an evenly distributed manner.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
REFERENCES:
patent: 4722584 (1988-02-01), Kakii et al.
patent: 4729624 (1988-03-01), Kakii et al.
patent: 5568581 (1996-10-01), Johnson et al.
Bayer AG Product Information Sheet,Processing Data for the Injection Moulder,1989, p. 24.
AG Technology,Gate Design—Table 6-1,1994-1996, p. 65.
Corning Cable Systems LLC
Stafira Michael P.
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