Abstract: A pivot structure as part of a framework for temporarily suspending equipment such as a movie screen from a ceiling track can include an oblong beam adjustably mounted to the track. The pivot structure can include a housing having a cylindrical bearing for rotatively mounting a spindle. A pair of separately actuatable brakes can clamp the spindle in a locked position. Each brake can include a barrel having a concavity in its outer cylindrical surface which when driven against the spindle discourages its rotation.

Abstract: A joint structure as part of a framework for temporarily suspending equipment such as a movie screen from a ceiling track can include an oblong C-channeled beam adjustably mounted to the track. A first locking pivot mechanism can secure to a middle part of the beam by having an axially movable axle upon which a housing can rotate. A cam mechanism drives the axle axially between an unlocked and locked position where a collar on the housing pinches the track against a T-shaped head attached to the axle. A second locking pivot mechanism having a rotation axis mutually orthogonal to the first pivot mechanism can provide additional adjustability.

Abstract: A framework for temporarily suspending a movie screen from a ceiling track includes an oblong beam adjustably mounted to the track. A locking pivot mechanism secured to a middle part of the beam supports a pair of oppositely extending cantelevered booms. Each boom can have inwardly extending substantially parallel rails similar to a ceiling track. Each of the booms can carry variously sized locking cradles which can support a spar for a movie screen or other structures. A second locking pivot mechanism having a rotation axis mutually orthogonal to the first pivot mechanism can provide the booms with additional adjustability.

Abstract: A barrier plate for supporting a cable within the internal channel of a ceiling mounted track having a pair of inwardly projecting parallel rails separated by a bottom slot. The barrier plate can be inserted completely into the internal channel and manipulated using a fingerhole through the plate to block downward movement of the cable through the slot. The plate can have radial disuniformities to frictionally bear against the pad of a user's finger to allow greater control of the plate orientation while engaged in the track channel.