An implant device can include a frame and a cover member for delivery to and occlusion of a target body vessel. The frame can include proximal and distal members, coupled by a link member structure, and can expand from a collapsed configuration to an expanded configuration. In the collapsed configuration, a first plane passes through the proximal member and a second plane passes through the distal member, and the link member extends substantially parallel relative to a longitudinal axis of the device. In moving to the expanded configuration, the first and second planes each move angularly, relative to the longitudinal axis, from the collapsed configuration by between about 10 degrees and about 170 degrees, and the link member foreshortens along the longitudinal axis to bias the proximal member toward the distal member.