the adjustable coupler 700 disassembly of the relatively movable components 1300 1310 is prevented u2014 yet when the security collar 300 is removed the adjustable coupler or clamping assembly 700 can be loosened to permit movement of the bracket 1310 and the mast component 1300 as is best shown in fig1 15 and 20 the security collar 300 principally includes two elongate components 310 320 that have adjacent end regions 311 321 respectively that are pivotally connected by the hinge 330 opposite halves 331 332 of the hinge 330 are pivotally connected by a non removable hinge pin of the hinge 330 that defines an imaginary axis about which the elongate components 310 320 can pivot between the closed position best shown in fig1 and 15 and an open position such as is shown in fig2 when the security collar 300 is in the closed position shown in fig1 and 15 the adjacent end regions 312 322 of the elongate components 310 320 respectively extend in side by side engagement in a direction leading generally away from the location of the hinge 330 the elongate component 310 of the security collar 300 includes a generally c shaped portion 340 that has a substantially uniform radius u201c r u201d about the central axis 295 that is shown in fig1 15 and 22 by a dot inasmuch as the central axis 295 is shown end on in these views of the drawings one end region 311 of the c shaped portion 340 is connected to the hinge component 331 an opposite end region of the c shaped portion 340.