US Patent 6854698 Arm apparatus for mounting electronic devices

An extension arm for mounting an electronic peripheral device includes upper and lower channel members. The channel members include a U-shaped body having a roller at each end thereof. At least one of the rollers includes a pair of spaced apart roller walls extending between the sidewalls forming the U-shaped body. The height of the roller walls from the bottom wall of the U-shaped body is less than the height of another portion of the roller from the bottom wall. This provides additional unobstructed space between two channels when assembled.