US Patent 7334693 Biased support

A biased support for booms that can pivot about a pin, for pivoting travel tracks for vehicles that run on rails, such as trolley travel tracks on booms. The booms are mounted to pivot via pins, the lock on the boom and slide plates on the upper and lower bearing points of the lock. At least one of the two slide plates in the upper bearing point is mounted elastically, so that when the boom is pivoted into the operating position, the entire lock is biased vertically and the pin is relieved of stress.