Abstract: A selectively engagable nut made up of plural nut portions which are able to move apart for disengagement with a screw and to move together to reengage. The nut portions are driven by pins extending into slots on the nut portions; the pins mounted in a rotating collar adjacent to the nut. The collar's pins, in a first rotational position holds the nut portions engaged with the screw. In an alternative rotational position, the pins drive and hold the nut portions apart to disengage with the nut portions. When the nut portions are in mutual contact, fingers are positioned on the nut portions in positions preventing the nut portions from moving apart so as to disengage the nut from the screw.

Abstract: A mounting structure for attaching an item in an area defined by an area wall is disclosed including an elongated track including a channel formed therein, the elongated track having at least one elongated channel wall and at least one elongated track flange adapted to be connected to the area wall, and a movable element movable to a selected position within the elongated channel and including at least one element flange for wedging engagement against the at least one elongated channel wall at the selected position.