B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
B66C23/62—Constructional features or details
B66C23/64—Jibs
B66C23/70—Jibs constructed of sections adapted to be assembled to form jibs or various lengths
B66C23/701—Jibs constructed of sections adapted to be assembled to form jibs or various lengths telescopic
B66C23/705—Jibs constructed of sections adapted to be assembled to form jibs or various lengths telescopic telescoped by hydraulic jacks