Cranes and excavators, as well as various other types of agricultural, industrial and construction machines, have heretofore been provided with wheels which are connected at fixed locations to the chassis and with outriggers which may be provided to support the chassis or vehicle body in various attitudes and to various degrees upon the ground. The outriggers may be formed with legs which are telescopingly extensible so that a pad or the like can rest upon the ground and can support the vehicle body which may be lifted to elevate the wheels above the ground.
It is also known to provide wheel-carrying assemblies which are provided on rigid traveling legs or legs which are hinged at fixed locations to the chassis to cooperate with a vehicle body which is capable of rolling and/or stepping movement along the ground.
For example, the vehicle body may have arms which are themselves hinged to a central support member so that the vehicle body may be raised into a portal or gantry configuration or lowered into a compact configuration with the center of the body close to the ground.
Such traveling outriggers enable the desired attitude of the vehicle to be maintained when the vehicle is used upon irregular terrain.
One of the problems encountered with earlier systems in which rolling and/or stepping travel is required, is that the usual wheel suspension or support does not permit rolling travel or travel on steep, banked or stepped terrain to a satisfactory degree.