Optical waveguides – With disengagable mechanical connector
Reexamination Certificate
1997-12-16
2001-05-08
Lee, John D. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
C385S134000, C385S139000
Reexamination Certificate
active
06227717
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to dust caps and in particular to dust caps for use with multiple types of telecommunications adapters and connectors.
2. Prior Art
Dust caps are used to prevent optical fiber adapters and connectors from being contaminated by dust, dirt, etc. Most existing adapter manufacturers utilize an industry-standard, soft-polymer dust cap for ST adapters and a flat-surfaced, rectangular dust cap for SC adapters. These styles are difficult to install and equally difficult to remove.
FIG. 1A
is a cross sectional view of a conventional dust cap
12
mounted to an ST adapter
10
. Conventional ST dust caps have several drawbacks. First, the dust cap
12
is generally cylindrical and does not provide any surface for gripping the dust cap during removal. In addition, the ST adapter includes keying posts
14
which prevent the dust cap
12
from making a good seal against the adapter body. Accordingly, dust can ingress into the inside of the ST adapter and deteriorate performance of the optical fiber coupled at the adapter
10
.
Conventional SC dust caps are effective dust caps, but are typically difficult to install and to remove.
FIG. 1B
is a perspective view of a conventional SC dust cap mounted to an SC adapter
13
. Both simplex and duplex SC dust caps include a segment
15
which inserts into the SC adapter cavity and a rectangular head
11
(whose thickness is approximately ⅛ inch) which seats against the facial end of the adapter
13
. To remove the cap, once installed, one must attempt to grip this rectangular head
11
. Since the width and length of head
11
is the same as (or very close to) the width and length of the adapter itself, and because the head
11
thickness is relatively thin (⅛″), it is difficult to grip this head
11
in order to pull it out of the SC adapter
13
. The width and length of the head
11
cannot be increased (which could provide an improved gripping surface) due to the constraints arising from the need to be able to install the adapter
13
through the standard rectangular panel cut-out with dust caps in place. Hence, if the head
11
was any larger, it wouldn't fit through the cut-out.
SUMMARY OF THE INVENTION
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the dust caps of the present invention. A first embodiment of the invention is a dust cap for use with ST adapters, ST connectors and SC connectors. The dust cap includes a sealing surface for contacting the bottom of an ST adapter for sealing the portion of the adapter containing the alignment sleeve. The dust cap also includes an opening having a reduced diameter to prevent contamination of the tip of the ferrule of an ST or SC connector. The dust cap may be formed in a duplex fashion and include a retaining strap for securing the dust cap to an ST adapter. An alternative embodiment of the invention is a dust cap having a first side for mating with either an SC or ST adapter and a second side for mating with either an SC or ST connector.
The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.
REFERENCES:
patent: 4640575 (1987-02-01), Dumas
patent: 5030120 (1991-07-01), Hartley
patent: 5202949 (1993-04-01), Hileman et al.
patent: 5506922 (1996-04-01), Grois et al.
patent: 5838855 (1998-11-01), Stephenson
patent: 5887098 (1999-03-01), Ernst et al.
Ott Conrad L.
Volansky Edward J.
Colburn LLP Cantor
Lee John D.
The Siemon Company
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