Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2002-03-01
2003-07-29
Feild, Lynn (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C385S081000, C385S056000
Reexamination Certificate
active
06599027
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ferrule holding structure for an optical connector component for use in connection between fiber optic cables.
2. Description of the Related Art
In general, in an optical communication system, several types of optical connector components have been used for detachably connecting between one fiber optic cable and another fiber optic cable or other optical device. One example of such optical connector components is an optical attenuator that is disclosed in TOKKOHEI No. 5-45924. Such optical attenuator is designed to have optical connectors mounted on both sides thereof so that an optical signal is relayed and attenuated between those optical connectors.
One such conventional type attenuator
1
is illustrated in FIG.
4
. Referring to this figure, the optical attenuator
1
includes a ferrule
2
for receiving a core optical fiber at the center thereof, a connection sleeve
3
for an attenuation film
61
affixed to an outer middle portion of the ferrule
2
, a split sleeve
4
affixed to an outer rear end portion of the ferrule
2
, a first plug frame
5
for surrounding and holding a front end portion of the ferrule
2
, a second plug frame
6
for surrounding and holding an opposite rear end portion of the ferrule
2
, and a housing member
7
for accommodating the first and second plug frames
5
and
6
.
The ferrule
2
is made of some ceramic material such as zirconia and has an axially elongated cylindrical form on which the attenuation film
61
is deposited for attenuating the passage of light.
The connection sleeve
3
is made of some metal material such as copper alloy in the form of a hollow cylinder that is affixed to the ferrule
2
with an adhesive. A flange
8
is affixed on an outer peripheral of the ferrule
2
adjacent a front end of the sleeve
3
. The flange
8
is made of metal and has predetermined number of grooves (not shown) formed on an outer surface thereof.
The split sleeve
4
is made of zirconia, for example, in the form of a hollow cylinder and is axially split to provide resiliency. The split sleeve
4
has a front end surface that is contact with the rear end surface of the connection sleeve
3
, and an opposite rear end surface that is backwardly projected beyond the rear end surface of the ferrule
2
.
The first plug frame
5
is made of some plastic material, for example, and it is generally in the form of a cubic in which a cylindrical cavity
9
is axially formed. An inner brim
10
is formed at the inner center portion of the first plug frame
5
and has keys provided at the rear end portion thereof in corresponding to the grooves in the flange
8
. Thereby, the ferrule
2
having the connection sleeve
3
mounted thereon is prevented from falling off the front end of the attenuator
1
. A first engagement portion
12
is formed on and projected from an outer surface of the first plug frame
5
, and a protrusion
13
is formed on the rear portion of the first engagement portion
12
. In addition, latch holes
14
are formed at positions opposite to each other on the rear portion of the first plug frame
5
, and elongated cutouts (not shown) are also formed at another positions opposite to each other to extend from the rear end of the first plug frame
5
.
The second plug frame
6
is made of some plastic material, for example, and includes, a cylindrical holding portion
16
in axial direction and a pair of thin plate-like resiliently deformable portions
17
that extend in cantilevered manner from the middle portion of the holding portion
16
toward the rear end of the attenuator
1
. Each of the deformable portions
17
has its rear end portion inwardly projected to form a second engagement portion
18
. The holding portion
16
has its outer surface on which latch projections
19
are formed at the positions corresponding to the latch holes
14
, and its inner surface on which a shoulder
20
is formed at the middle portion thereof. The holding portion
16
further includes an inwardly projecting fall-off prevention portion
21
formed on the rear end portion thereof for preventing the ferrule
2
fixed to the split sleeve
4
from falling off the holding portion
16
.
The housing member
7
is made of stainless steel, for example, and includes a front end portion
22
that is mated with an adapter (not shown) and a rear end portion
23
with which a plug (not shown) is mated. The front end portion
22
has such width that is smaller than that of the rear end portion
23
so that there is a difference in width produced therebetween. An opening
24
is provided on each of both sidewalls of the front end portion
22
. Accordingly the first engagement portion
12
and the protrusion
13
may cause an axial floating movement along the openings
24
. In addition, a key projection
25
is formed on an outer surface of the front end portion
22
, and the corresponding guide recess
26
is formed in the sidewall of the rear end portion
23
so that it axially extends from the rear end thereof.
Now, the process of assembling the prior art optical attenuator
1
having the configuration as above will be described.
The connection sleeve
3
is affixed to the ferrule
2
with an adhesive. Then, the flange
8
is affixed so that it is contact with the front end surface of the connection sleeve
3
. The split sleeve
4
is press-fitted so that it is contact with the rear end surface of the connection sleeve
3
. Thereafter, the front end portion of the ferrule
2
having the connection sleeve
3
, the split sleeve
4
and the flange
8
mounted thereon is inserted into the cavity
9
of the first plug frame
5
from the rear side thereof In this connection, the groove (not shown) on the flange
8
is mated with the key
11
of the first plug frame
5
so that the flange
8
abuts the brim
10
. Then, the second plug frame
6
is inserted into the first plug frame
5
in such manner that the holding portion
16
of the second plug frame
6
surrounds the rear end portion of the split sleeve
4
. Thereafter, the second plug frame
6
is further inserted until the latch projection
19
snaps into the latch hole
14
upon which the second plug frame
6
is coupled to the first plug frame
5
. In this condition the ferrule
2
may floatingly be moved in the axial direction between the inner brim
10
of the first plug frame
5
and the shoulder
20
of the second plug frame
6
. Finally the first and second plug frames
5
and
6
coupled together are inserted into the housing member
7
from the rear side thereof until the first engagement portion
12
and the protrusion
13
become received in the opening
24
. Accordingly, the first and second plug frames
5
and
6
are held in the housing member
7
, but they may floatingly be moved in the axial direction.
The optical attenuator
1
that is assembled in the manner as above is then connected as follows: When the front end portion
22
is mated with the adapter (not shown) so that the key projection
25
is received in the guide recess (not shown) of the adapter, then the first engagement portion
12
is engaged with the adapter. On the other hand, when the rear end portion
23
is mated with the plug (not shown) so that the key projection (not shown) of the plug is received in the guide recess
26
, then the second engagement portion
18
is engaged with the plug. As the result, the plug is connected with the adapter through the optical attenuator
1
.
However, the prior art optical connector components such as those including the optical attenuator
1
as described above are generally defective in that they need great number of parts and assembling steps, and involves many laborious works because of the sleeve
3
and the flange
8
made of metal. In addition, they are difficult to reduce the manufacturing cost.
Because an adhesive is used for affixing the connection sleeve
3
to the ferrule
2
, any excessive amount of adhesive that has come out of the end of the connection sleeve
3
flows into between conn
Miyake Yukinori
Sumida Shin
Yanagi Shuichi
Yoshida Takumi
Cohen & Pontani, Lieberman & Pavane
Feild Lynn
Hirose Electric Co. Ltd.
Nguyen Son V.
LandOfFree
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