Optical waveguides – With disengagable mechanical connector
Reexamination Certificate
2002-01-31
2004-06-08
Ullah, Akm Enayet (Department: 2874)
Optical waveguides
With disengagable mechanical connector
C385S062000, C385S076000, C385S088000, C024S605000, C024S614000, C292S137000, C439S152000, C439S258000, C439S266000, C439S370000
Reexamination Certificate
active
06746158
ABSTRACT:
BACKGROUND
State-of-the-art digital communication switches, servers, and routers currently use multiple rows of duplex LC connector optical transceivers to meet information bandwidth and physical density needs. To be a commercially fungible product, the optical transceivers must have basic dimensions and mechanical functionality that conform to an industry standard Multi-Source Agreement (MSA) such as set forth in the Small Form Factor (SFF) committee's INF-8074i “SFP Transceiver” document. Many optical transceiver mechanical designs that comply with and add value beyond the basic mechanical functionally set forth in the MSA are possible.
FIG. 1
illustrates a standard configuration for a system
100
including a fiber optic transceiver module
110
and a cage
120
. Fiber optic transceiver module
110
contains a transceiver that converts optical data signals received via an optical fiber (not shown) into electrical signals for an electrical switch (not shown) and converts electrical data signals from the switch into optical data signals for transmission. Cage
120
would typically be part of the switch and may be mounted in closely spaced rows above and below a printed circuit board.
When plugging module
110
into a switch, an operator slides module
110
into cage
120
until a post
114
on module
110
engages and lifts a latch tab
122
on cage
120
. Module
110
then continues sliding into cage
120
until post
114
is even with a hole
124
in latch tab
122
at which point latch tab
122
springs down to latch module
110
in place with post
114
residing in hole
124
. Post
114
is shaped such that an outward force on module
110
does not easily remove module
110
from cage
120
.
Module
110
has a delatch mechanism
130
, which resides in a channel extending away from post
114
. In a latched position, delatch mechanism
130
is outside cage
120
, and post
114
is in hole
124
. To remove module
110
, delatch mechanism
130
is slid toward cage
120
until wedges
132
on delatch mechanism
130
slide under and lift latch tab
122
to a level above post
114
. Module
110
can then be slid out and removed from cage
120
.
Operation of delatch mechanism
130
can be awkward since removal of module
110
requires pushing in on delatch mechanism
130
while pulling out module
110
. Additionally, when module
110
is in an array of modules in an optical switch, modules above module
110
will often block easy access to delatch mechanism
130
, making removal of module
110
more difficult. Surrounding modules also make each module more difficult to grip.
Other module delatch mechanisms have been developed in attempts to simplify the removal procedure. One such module has a flexible strip that is attached to the module and resides under the latch tab in the latched position. To delatch the module, an operator pulls up and out on the flexible strip, and the flexible strip lifts the latch tab off the post on the module. Releasing the latch tab and removing the module in this manner requires significant upward force. For many operators, the operation of this delatch mechanism is not intuitive since pulling directly out on the flexible tab will not release the module. Additionally, in a high-density configuration, surrounding modules can make the flexible tab difficult to grip.
Another “pull-to-detach” mechanism provides the module with a post on a lever arm and a flexible handle mounted to a rod. When the flexible handle is pulled, the rod forces the lever arm to rotate and lower the post away from the cage, releasing the module from the latch on the cage. The pulling force on the flexible handle then slides the module out of the cage. Return springs that hold the lever arm and the post in position are features molded into the plastic housing. This system requires an operator to apply a great deal of force to remove the module.
In view of the limitations of current systems, fiber optic transceiver modules need new types of delatch mechanisms that are intuitive to operate, do not require excessive force, and are easily accessible in high density module arrangements.
SUMMARY
In accordance with an aspect of the invention, a pulling on a delatch mechanism for an optical transceiver module lifts a latch tab off a post on the module before transferring pulling force to the module for removal. Accordingly, operation of the delatch mechanism is intuitive in that pulling directly out on the delatch mechanism pulls out the module.
One embodiment of the delatch mechanism includes one or more wedges that reside inside pockets adjacent the post on the module when the module is latched in a cage. A pulling force on a handle attached to the wedges pulls the wedges out of the pockets causing the wedges to rise and lift a latch tab. When the delatch mechanism moves to a limit of its range of motion, the latch tab is above the post on the module, and the pulling force transfers to the module to pull the module out of the cage. The delatch mechanism can include a spring system that returns the wedges to their respective pockets for latching, allows movement of the wedges relative to the module for lifting of the latch tab, and locks into the module to transfer pulling force to the module during removal. The delatch mechanism can employ a variety of handles including but not limited to a bail, a flexible tab, or a fixed tab, which can be easily accessed even in dense module arrays.
Another embodiment of the invention is a module assembly such as a fiber optic transceiver module assembly that includes a module body and a delatch mechanism. The module body includes a latch post and a pocket adjacent the latch post. The delatch mechanism includes a wedge with a top that is below the top of the latch post when the wedge is in the pocket. When the delatch mechanism is pulled from a first position to a second position, the wedge rises out of the pocket so that the top of the wedge is at or above the top of the latch post.
A spring system can be attached so that pulling the delatch mechanism from the first position to the second position compresses the spring system and transfers pulling force to the module body. One specific spring system uses spring arms having ends in notches on opposite sidewalls of a channel in the module body, and the spring arms and the wedge can be part of an integrated structure that slides along the channel.
Generally, a handle enables a user to pull the delatch mechanism. The handle can include a bail that is connected to an integrated structure including the wedge and/or one or more ridges for gripping when the bail is inconveniently located. Alternatively, the handle can include a flexible tab that is looped though an opening in the integrated structure, or a portion of the integrated structure that extends beyond the module body.
Another embodiment of the invention is a method for removing a fiber optic transceiver module from a cage. The method includes pulling a delatch mechanism from a first position to a second position relative to the module. Pulling the delatch mechanism to the second position moves a wedge causing the wedge to lift a tab on the cage to free a post on the module from a hole in the tab. In the second position, the delatch mechanism is fixed relative to the module so that the further pulling applies force to the module and removes the module from the cage.
REFERENCES:
patent: 6447170 (2002-09-01), Takahashi et al.
patent: 6485322 (2002-11-01), Branch et al.
patent: 6570768 (2003-05-01), Medina
patent: 2002/0142649 (2002-10-01), Baugh et al.
patent: 2003/0133667 (2003-07-01), Chiu et al.
Agilent Technologie,s Inc.
Connelly-Cushwa Michelle R.
Ullah Akm Enayet
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