Nippon telegraph and telephone corporation

Details Nippon telegraph and telephone corporation Nippon telegraph and telephone corporation

1999-06-29

2001-09-18

Sircus, Brian (Department: 2839)

Electrical connectors

With coupling movement-actuating means or retaining means in...

Retaining means

C439S354000, C385S076000

Reexamination Certificate

active

06290527

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a connector plug used in an optical connector that connects optical communication cables using single- or multi-core optical fibers.
2. Description of the Prior Art
Optical communication systems have conventionally employed various kinds of optical connectors for connecting optical communication cables. In recent years, an MT (Mechanically Transferable) type connector and an MPO (Multifiber Push-On) type connector capable of being engaged and disengaged simply by a push-pull operation have been proposed as connectors that can easily connect or disconnect optical fiber tapes. These types of connectors all use an MT type ferrule in an optical fiber connecting portion. The optical fiber connectors using the MT type ferrule are constructed so as to be able to easily align the end faces of mating optical fibers by guide pins and are very useful in terms of ease of use, weight and cost.
In recent years, an RJ (Regular Jack) type optical connector has been proposed (for example by U.S. Pat. No. 5,481,634) which incorporates a connector ferrule in an RJ type housing and enables connection and disconnection of optical fibers by an operation similar to the one performed on the electric connector.
The RJ type optical connector applies the connection structure of the electric connector to the optical connector, and its construction is shown in FIG.
17
.
The optical connector shown in the figure comprises a pair of RJ type connector plugs
1
(only one of the pair is shown) and an adapter
2
. The connector plugs
1
each incorporate a ferrule
4
holding an optical fiber
3
therein. In this optical connector, when the pair of connector plugs
1
are inserted into the adapter
2
, end faces of the optical fibers of the opposing connector plugs
1
contact each other, thus connecting the optical fibers
3
of the connector plugs
1
.
That is, inserting the connector plugs
1
into the adapter
2
causes an elastic engagement piece
1
a
provided on one side surface of each connector plug
1
to snap into a recessed portion in the adapter
2
, thus holding the connector plug
1
and the adapter
2
in a connected state. The connector plug
1
can be disconnected by pressing a press portion
1
c
of the elastic engagement piece
1
a
toward the plug body side while pulling the connector plug from the adapter
2
.
With the conventional RJ type optical connector, however, pressing the press portion
1
c
of the elastic engagement piece
1
a
easily allows the connector plug to disengage from the adapter
2
. Therefore, there is a possibility that the connection may easily be lost as a result of the press portion
1
c
of the elastic engagement piece
1
a
contacting external objects. This raises a problem of lack of reliability of the optical connector.
Further, because the elastic engagement piece
1
a
including the press portion
1
c
protrudes largely outwardly from the optical connector, cables or the like are likely to get caught by the engagement piece. As described above, inadvertent contact of the elastic engagement piece
1
a
with other objects will easily result in disconnection.
Another problem is that, when multi-core optical fibers are to be connected by the conventional optical connector, it is difficult to align the positions of the mating optical fibers.
An object of the present invention is to provide a connector plug which can easily be connected to and disconnected from the adapter and at the same time whose connection cannot easily be broken.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a connector plug can be removably snap-fitted into an adapter having a cavity therein for receiving the connector plug and holes for locking the connector plug, and comprises: at least one optical fiber; a ferrule for holding the optical fiber so that each end face of the optical fiber is exposed; a housing for receiving the ferrule and the fiber; and a plurality of elastic engagement pieces extending from a plurality of locations on the housing, the elastic engagement pieces each having a projecting engagement portion, the projecting engagement portions being adapted to snap into the holes of the adapter and become locked there when the connector plug is inserted into the adapter.
The elastic engagement pieces extend, for example, in an axial direction of the optical fiber. Spaces for the elastic engagement pieces to elastically deform are formed between a back surface of each of the elastic engagement pieces and the housing.
Because the connector plug is connected to the adapter by a plurality of elastic engagement pieces, the connected state is prevented from being disturbed inadvertently by contact with external objects, thus improving the reliability of the optical connector.
Further, if the elastic engagement pieces are each formed with a projecting press portion at a rear end portion thereof which is pressed to elastically deform the elastic engagement piece toward its back surface side to unlock the engagement portion of the elastic engagement piece from the hole of the adapter, the connection and disconnection between the connector plug and the adapter can easily be performed. This construction is practically very useful.
Further, if a projection height of the press portion is set almost flush with a surface of the housing of the adapter when the connector plug is inserted into the adapter, or if the adapter is provided with receptor portions that receive the press portions of the elastic engagement pieces by enclosing the press portions around their circumference and the projection height of the press portion is set almost equal to the height of the receptor portion, it is possible to prevent the press portions from becoming entangled with cables or the like and thereby keep the wiring state of the optical cables in good condition.
In another aspect of the invention, the connector plug can be removably snap-fitted into an adapter having a cavity therein for receiving the connector plug and holes for locking the connector plug, and comprises:
At least one optical fiber; a ferrule for holding the optical fiber so that each end face of the optical fiber is exposed; a housing for receiving the ferrule and the fiber; a housing for holding the optical fiber so that an end face of the optical fiber is exposed; an elastic engagement piece extending from the housing, the elastic engagement piece having a projecting engagement portion and a projecting press portion that can be pressed, the projecting engagement portion being adapted to snap into the hole of the adapter and become locked there when the connector plug is inserted into the adapter; and a stopper for locking the press portion of the elastic engagement piece from being pressed; wherein, in a state where the press portion is not locked by the stopper, the press portion is pressed to unlock the engagement portion of the elastic engagement piece from the hole. The elastic engagement piece extends, for example, in an axial direction of the optical fiber, and a space for the elastic engagement piece to elastically deform is formed between a back surface of the elastic engagement piece and the housing.
In this invention, because the stopper locks the elastic engagement piece from being pushed down, there is no possibility of the connector plug inadvertently disengaging from the adapter even when the press portion contacts external objects, thus improving the reliability of the optical connector.
Further, if the stopper is made movable between a locking position where the stopper locks the pressing operation of the press portion and an unlocking position where the press portion is unlocked, the movement of the elastic engagement piece can be locked/unlocked by a simple operation of moving the stopper.
Further, if a stopper locking means is provided which restricts (or locks) the movement of the stopper itself at the locking position, it is possible to reliably prevent the stopper from inadvertently getting displaced and nullify

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