Method and apparatus for releasably locking an optical transceiver into a cage attached to an electronic board

The present disclosure relates to a locking mechanism for releasably locking an optical transceiver into a cage that is attached to an electronic board, and more particularly, to an optical transceiver designed to comply with the XFP computer protocol.

XFP is a protocol agreed to by industry participants to define standard components and architectures for ten gigabit small form factor pluggable modules. The XFP pluggable module is an optical transceiver that has standard features such as outer envelope size, internal electrical specifications, and optical connector ports. Some mechanical design features, such as the locking mechanism for releasably connecting a module to a standard cage attached to a computer board have been left to the component manufactures to develop.

Thus, there is a need for a reliable and inexpensive locking mechanism for securing an optical transceiver to a cage on a computer board and, more generally, there is a need for a locking mechanism for locking components within a standard cage structure that is both inexpensive and reliable.

FIG. 1 is an exploded perspective view of a transceiver and cage mounted on an electronic board;

FIG. 2 is an enlarged perspective view of the transceiver shown in FIG. 1 ;

FIG. 3 is a partial cross-sectional view of the cage shown in FIG. 1 ;

FIG. 4 is a partial cross-sectional view of the transceiver mounted as shown in FIG. 2 in the cage as shown in FIG. 3 in a locked position;

FIG. 5 is another partial cross-sectional view similar to that of FIG. 4 but showing the transceiver mounted into the cage in an unlocked position; and

FIGS. 6A–6E show the transceiver with a bail in various positions ranging from fully locked to fully unlocked.

Referring now to the Figures, and more particularly to FIG. 1 , an optical transceiver 10 is shown in an exploded view with a cage 12 installed on an electronic board 14 . The cage 12 can be permanently installed on the board 14 for providing a connector housing in which the optical transceiver 10 can be installed. The transceiver 10 includes a locking mechanism 16 for releasably locking the optical transceiver 10 with respect to the fixed cage 12 . The cage 12 includes a pair of inwardly biased locking tabs 18 a , 18 b (best seen in FIGS. 3–5 ) extending from the sides 20 a , 20 b of the cage 12 . Each tab 18 a , 18 b is moveable between an inner biased position shown in solid line and an outer position substantially flush with the sides 20 a , 20 b of cage 12 , shown in dashed line in FIG. 3 . The tabs 18 a , 18 b are adapted to lockingly engage the transceiver 10 when biased in the inner position and to disengage from the transceiver 10 when forced to the outer position.

Referring now to FIG. 2 , an enlarged view of the locking mechanism 16 is shown. The transceiver 10 includes a pair of levers 26 a , 26 b , each having first and second ends 28 , 30 respectively. Each lever 26 a , 26 b is operable for engaging one of the locking tabs 18 a , 18 b (shown best in FIGS. 3–5 ). The levers 26 a , 26 b are operable for engaging and moving the locking tabs 18 a , 18 b from the biased inner or locked position (shown in solid in FIG. 3 ) to outer or unlocked position (shown in phantom in FIG. 3 ). In the locked position as shown in FIG. 4 , the locking tabs 18 a , 18 b abut against a shoulder 32 formed on the transceiver 10 . The locking tabs 18 a , 18 b are moved to the outer unlocked position (phantom line in FIG. 3 ) when the levers 26 a , 26 b are moved in the direction of the arrow 34 (see FIG. 5 ). When the locking tabs are unlocked, the transceiver 10 may removed from the cage 12 .

A pair of substantially L-shaped latches 36 a , 36 b is positioned on each side of the transceiver 10 . Each latch 36 a , 36 b includes a first surface 38 (see FIG. 5 ) for engaging and moving the levers 26 a , 26 b in the direction of arrow 40 towards a first or locked position shown in FIGS. 4 and 6A . The latches 36 a , 36 b also include a second surface 44 for engaging and moving the levers 26 a , 26 b toward a second or unlocked position shown in FIG. 6E . The locked and unlocked positions correspond to the transceiver 10 being locked and unlocked relative to the cage 12 . A pair of pivot pins, one of which is shown at 48 , extend from the transceiver 10 on opposite sides for pivotally connecting each latch 36 a , 36 b to the transceiver 10 . The first and second surfaces 38 , 44 of the latches 36 a , 36 b extend from the axis of the pins 48 and substantially orthogonally from one another.

The transceiver 10 includes grooved pockets 50 positioned on each side of the transceiver 10 for receiving and permitting the levers 26 a , 26 b to reciprocatingly slide therein. The first surfaces 38 of the latches 36 a , 36 b are operable for contacting a first surface 52 (best seen in FIGS. 5 and 6 a ) of the levers 26 a , 26 b and moving the levers towards the locked position in the direction of arrow 40 (shown in FIG. 3 ). The second surfaces 44 of the latches 36 a , 36 b are operable for contacting a second surface 54 of the levers 26 a , 26 b and moving the levers 26 a , 26 b towards the open position in the direction of arrow 34 .

In an illustrative embodiment, the levers 26 a , 26 b include a substantially inverted V-shaped portion having surfaces 54 , 56 formed adjacent the second end 30 of the levers 26 a , 26 b . The forward side of the inverted V-shaped portion defines the second surface 54 that is engageable with the latches 36 a , 36 b . The latches 36 a , 36 b engage the surfaces 54 of the levers 26 a , 26 b when the levers 26 a , 26 b are moved from the locked position shown in FIGS. 4 and 6A to the unlocked position shown in FIGS. 5 and 6E . The levers 26 a , 26 b further include an outwardly angled portion 58 formed adjacent the first ends 28 of the levers 36 a , 36 b (shown best in FIGS. 4 and 5 ). The outwardly angled portions 58 are operable for engaging the locking tabs 18 a , 18 b causing the locking tabs 18 a , 18 b to move into the outer or unlocked position when the levers 36 a , 36 b are moved in the direction of arrow 34 (best seen in FIGS. 5 and 6E ). The outwardly angled portion 58 can extend at a substantially 45 degree angle from a longitudinal axis as shown in the illustrative embodiment, however, one skilled in the art will understand that a range of angles would be effective in actuating the locking tabs 18 a , 18 b from the inwardly biased position to the outer unlocked position.

Referring again to FIGS. 2 and 6 A– 6 E, the locking mechanism 16 includes a bail 60 extending from the latches 36 a , 36 b for permitting manual actuation of the latches 36 a , 36 b between the unlocked ( FIG. 6E ) and locked ( FIG. 6A ) positions and vice versa. The latches 36 a , 36 b will urge the levers 26 a , 26 b towards the locked position ( FIG. 6A ) when the bail 60 is rotated in a first direction defined by a curved arrow 62 shown in FIG. 6C . The latches 36 a , 36 b will urge the levers 26 a , 26 b towards the unlocked position ( FIG. 6E ) when the bail 60 is rotated in a second direction defined by a curved arrow 64 shown in FIG. 6D . The bail 60 includes a cross-member 62 extending between two sides 64 a , 64 b best seen in FIG. 2 . The cross member 62 provides an easily accessible member for manually gripping and rotating the bail 60 in a desired direction. The bail 60 is fully closed when further rotation of the bail 60 in the direction of the arrow 62 is restricted by the first ends 28 of the levers 26 a , 26 b hitting stops 66 defined by distal ends of the pockets 50 . The transceiver 10 is locked relative to the cage 12 when the bail 60 is in the closed position shown in FIG. 6A . An optical connector 70 , shown in FIG. 2 , is only connectable to the transceiver 10 when the bail 60 is in the closed position shown in FIGS. 1 , 2 , and 6 A.

A fully opened position as shown in FIG. 6E is defined by rotating the bail 60 in the direction of the arrow 64 approximately seventy degrees (70°) from the locked position, as shown in FIG. 6A . The transceiver 10 is unlocked and can be removed from the cage 12 when the bail 60 is in the open position. The optical connector 70 is prevented from connecting to the transceiver 10 when the bail 60 is in the open position of FIG. 6E .

The levers 26 a , 26 b most preferably have a hardened wear resistant material coating 76 added to the outer surfaces thereof. The coating reduces wear from contacting surfaces, such as the grooved pockets 50 , the locking tabs 18 a , 18 b , and the latches 36 a , 36 b . The coating 76 can be formed from a nickel based material, or as one skilled in the art will readily understand, many other types of material coating such as titanium nitride and/or composite coatings. The coating 76 can be formed on the levers 26 a , 26 b by any one of a number of methods, some of which can include dipping, electroplating, and spraying. The levers 36 a , 36 b and bail 60 can be made from any material having mechanical properties adequate for use in this environment, however, die cast zinc alloy is a preferred material.

In operation, the transceiver 10 is slid into the cage 12 . The bail 60 is manually actuated in the direction of the arrow 62 (see FIG. 6C and generally FIGS. 6E through 6A ) such that the latches 36 a , 36 b make contact with the levers 26 a , 26 b and move the levers 26 a , 26 b in the direction of arrow 40 as shown in FIGS. 3 and 4 . The angled portions 58 of the levers 26 a , 26 b engage the inwardly biased locking tabs 18 a , 18 b causing the tabs 18 a , 18 b to move to the outer position substantially flush with the sidewalls 20 a , 20 b as shown in FIG. 5 . After the angled portions 58 traverse past the locking tabs 18 a , 18 b , the tabs 18 a , 18 b then move back to the biased inward locking position shown best in FIGS. 4 and 6A . The bail 60 is fully closed when the levers 26 a , 26 b hit stops 66 defined by the ends of the pockets 50 . The transceiver 10 is locked into the cage 12 and an optical connector 70 can be attached to the transceiver 10 when the bail 60 is in the closed or locked position shown in FIG. 6A .

All optical connectors 70 must be disconnected from the transceiver 10 prior to removing the transceiver 10 from the cage 12 . After the optical connectors 70 are disconnected, the bail 60 can be manually rotated in the direction defined by arrow 64 (FIG. 6 D). The second surface 44 of each latch 36 a , 36 b contacts the second surfaces 54 of the levers 26 a , 26 b causing the levers 26 a , 26 b to move in the direction defined by arrow 34 shown in FIGS. 3 and 4 , when the bail 60 is rotated in the second direction defined by arrow 64 in FIG. 6D . The outwardly angled portions 58 of the levers 26 a , 26 b actuate the locking tabs 18 a , 18 b toward the outer or unlocked position ( FIGS. 5 and 6E ) allowing the shoulder 32 of the transceiver 10 to slide past the tabs 18 a , 18 b . The bail is shown in various positions ( FIGS. 6B , 6 C, and 6 D) between fully closed ( FIG. 6A ) and fully open ( FIG. 6E ). When the bail 60 is open the transceiver 10 can be removed from the cage 12 .

One of the advantages of this bail latch/delatch design is the unique shape of the bail 60 , which allows the user to pull down the bail 60 from the top with one finger or from side with both a thumb and an index finger. Either mode of operation can be chosen based on the module configuration depending on how the multiple units are stacked and arranged in an electronic chassis.

Although certain examples have been disclosed and described herein in accordance with the teachings of the present invention, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention fairly falling within the scope of the appended claims, either literally or under the doctrine of equivalents.