Patent ID: 7219810

Claim:
Mobile crane ( 10 ), comprising a long main boom ( 12 ) comprising two boom parts ( 14 , 16 ) pivotally linked together, a swivel point ( 18 ) at which said two boom parts ( 14 , 16 ) are pivotally linked, said two boom parts ( 14 , 16 ) being structured and arranged with respect to one another such that when said main boom ( 12 ) is initially raised from a flat, extended position along the ground, the boom parts ( 14 , 16 ) bend with respect to one another, as said main boom ( 12 ) is raised, an upper one ( 16 ) of the boom parts ( 14 , 16 ) swivels with respect to a lower one ( 14 ) of the boom parts ( 14 , 16 ) to position the main boom ( 12 ) in extended or partially-extended final erection position with the boom parts ( 14 , 16 ) extended either substantially colinear or at a swivel angle with respect to one another, at least one strut member ( 20 ) positioned to swivel on an additional swivel joint ( 22 ) positioned upon one ( 16 ) of said boom parts ( 14 , 16 ), an adjustment coil ( 42 ) positioned upon the main boom ( 12 ) and an adjustment pulley ( 48 ) arranged to be drawn to a tip of the strut member ( 20 ) by turning said adjustment coil ( 42 ), a pin ( 50 ) situated upon said pully ( 48 ), a hook ( 52 ) pivotally mounted upon said strut member ( 20 ), and said additional swivel joint ( 22 ) positioned upon the upper boom part ( 16 ), with said pin ( 50 ) and hook ( 52 ) structured and arranged to engage one another upon raising said strut member ( 20 ) with respect to said respective boom part ( 16 ).