the boom 86 under continued application of the applied load and or under its own weight the springs 210 extend thereby resisting downward pivoting of the boom 86 and controlling the descent of the boom 86 in a manner to avoid injury to anyone and or damage to anything beneath the boom 86 as well as to avoid damage to the projector 88 and the mirror 89 supported by the boom 86 as with the embodiment of fig1 to 5 the number and arrangement of mechanical fuse assemblies and coil springs 210 can be varied turning now to fig8 and 9 yet another embodiment of a safety device is shown and is generally identified by reference numeral 300 the safety device 300 in this embodiment is very similar to that shown in fig6 and 7 as can be seen the safety device 300 comprises a pair of spaced bands 302 a and 302 b respectively with each band having a pair of laterally spaced holes 304 provided therein the holes 304 in band 302 a accommodate fasteners that secure the band to the horizontal flange 96 the holes 304 in band 302 b accommodate fasteners that secure the band to the top of the boom 86 the bands 302 a and 302 b are joined by a central mechanical fuse assembly 306 a pair of dashpots 310 i e pneumatic or hydraulic cylinder and piston arrangements also joins the bands 302 a and 302 b each dashpot 310 is positioned on an opposite side of the central mechanical fuse assembly 306.