A pivot assembly (38, 39), comprising: a pivoting element (60, 62, 66, 68) having a plurality of engagement surfaces, and an arcuate channel radially spaced from and coaxial with a central axis (A-A); a first pivot stop having a carriage arranged to slide relative to the arcuate channel, and an engagement member slidably disposed within the carriage, the engagement member linked to a tab disposed radially outward away from the carriage and the central axis (A-A); a lock, wherein the engagement member is biased radially inward relative to the carriage and the central axis (A-A) to engage one of the plurality of engagement surfaces of the pivoting element (60, 62, 66, 68) to lock rotation of the first pivot stop, and wherein radially outward movement of the tab disengages the engagement member from the one of the plurality of engagement surfaces to unlock rotation of the first pivot stop from the pivoting element (60, 62, 66, 68), wherein the pivot assembly (38, 39) further comprises: a second pivot stop; a strut head disposed adjacent to the pivoting element (60, 62, 66, 68) and configured to be rotatable relative to the pivoting element (60, 62, 66, 68); a strut (22, 32) extending from the strut head and defining a first stop edge (144, 146) adapted to abut against the first and second pivot stops (40, 42) to prevent rotation of the strut (22, 32) past the first and second pivot stops (40, 42), wherein the first stop edge (144, 146) is configured to rotate through the arcuate channel to abut against a locked position of the first pivot stop, the locked position preventing the strut (22, 32) from rotating relative to the pivoting element (60, 62, 66, 68) past the locked position, characterized in that the lock is arranged to fit over the tab and a portion of the carriage to prevent movement of the engagement member, wherein the lock is configured to fit over a surface of the tab and snap to at least one flange (49, 51) defined by the carriage to arrest movement of the tab relative to the carriage and the at least one flange (49, 51) comprises first and second flanges (49, 51), the lock forms first and second arms (65, 67) having a width therebetween that is smaller than a width of the tab, the first and second arms (65, 67) are arranged to deflect over the surface of the tab to snap against the first and second flanges (49, 51) once the lock is fully placed over the tab and the carriage. a pivoting element (60, 62, 66, 68) having a plurality of engagement surfaces, and an arcuate channel radially spaced from and coaxial with a central axis (A-A); a first pivot stop having a carriage arranged to slide relative to the arcuate channel, and an engagement member slidably disposed within the carriage, the engagement member linked to a tab disposed radially outward away from the carriage and the central axis (A-A); a lock, wherein the engagement member is biased radially inward relative to the carriage and the central axis (A-A) to engage one of the plurality of engagement surfaces of the pivoting element (60, 62, 66, 68) to lock rotation of the first pivot stop, and wherein radially outward movement of the tab disengages the engagement member from the one of the plurality of engagement surfaces to unlock rotation of the first pivot stop from the pivoting element (60, 62, 66, 68), wherein the pivot assembly (38, 39) further comprises: a second pivot stop; a strut head disposed adjacent to the pivoting element (60, 62, 66, 68) and configured to be rotatable relative to the pivoting element (60, 62, 66, 68); a strut (22, 32) extending from the strut head and defining a first stop edge (144, 146) adapted to abut against the first and second pivot stops (40, 42) to prevent rotation of the strut (22, 32) past the first and second pivot stops (40, 42), wherein the first stop edge (144, 146) is configured to rotate through the arcuate channel to abut against a locked position of the first pivot stop, the locked position preventing the strut (22, 32) from rotating relative to the pivoting element (60, 62, 66, 68) past the locked position, characterized in that the lock is arranged to fit over the tab and a portion of the carriage to prevent movement of the engagement member, wherein the lock is configured to fit over a surface of the tab and snap to at least one flange (49, 51) defined by the carriage to arrest movement of the tab relative to the carriage and the at least one flange (49, 51) comprises first and second flanges (49, 51), the lock forms first and second arms (65, 67) having a width therebetween that is smaller than a width of the tab, the first and second arms (65, 67) are arranged to deflect over the surface of the tab to snap against the first and second flanges (49, 51) once the lock is fully placed over the tab and the carriage.