Patent ID: 8755006

Claim:
A back plate comprising: a bottom plate having a periphery; an inner side frame having a top edge and a bottom edge secured on the periphery, the top edge being coupled directly to the bottom edge, wherein the inner side frame extends upwards from the periphery and surrounds the bottom plate to form a container space, the inner side frame having a first surface facing the container space and a second surface opposite to the first surface; a folded portion extending from the top edge of the inner side frame in a direction vertical to the top edge and turned back to the second surface of the inner side frame, and thus forming a ridge extending in a direction parallel to the top edge; an outer strip positioned out of the container space, wherein the outer strip is secured on the folded portion and extends downwards from the folded portion, so that a gap is formed between the outer strip and the inner side frame, wherein the outer strip and the bottom plate are respectively disposed at opposite sides of the inner side frame; and a fastener disposed on the outer strip.