Patent ID: 7593237

Claim:
A retention assembly for assembling an expansion card, the expansion card being mounted to an expansion card bracket attached to an enclosure, the retention assembly comprising: a fastening module for being fixed to the enclosure, the fastening module comprising a first fastening member and a second fastening member; and a foldable holder rotatably connected to the fastening module, the foldable holder comprising a resisting portion and two extending portions formed at opposite ends of the resisting portion, and the foldable holder configured to resist the expansion card bracket when the retention assembly is in a closed state and being away from the expansion card bracket when the retention assembly is in an opened state; wherein one of one extending portion of the fastening module and the second fastening member of the foldable holder forms a protrusion, the other one of the extending portion and the second fastening member defines at least two spaced positioning depressions and a circular-shaped guiding groove, the guiding groove substantially having a curvature of a circle having a center, the positioning depressions being at ends of the guiding groove, a depth and a width of the positioning depressions is larger than that of the guiding groove, the protrusion slidably engages in the guiding groove, and the foldable holder is positioned relative to the fastening module when the protrusion engages in each of the positioning depressions.