Excavator having lifting legs and cooperating boom mounted bucket for "walking"

Claim 1

an excavator, comprising: frame means having wheel means thereon; rail means mounted on said frame means; a rail carriage mounted on said rail means, and movable along the longitudinal axis thereof; first motive means connected between said rail carriage and said rail means, operable to effect movement of said rail carriage along the longitudinal axis of said rail means; a boom and bucket assembly carried by said rail carriage, and including a second motive means operable separate from said first motive means to move said boom and bucket in a generally vertical plane to engage said bucket with the earth, said generally vertical plane including the longitudinal axis of said rail means; and a lifting leg assembly mounted on each of the opposite sides of said rail carriage to project laterally from the longitudinal axis thereof, each of said lifting leg assemblies including a third motive means operable separate from said first and said second motive means to press the lower end of the associated leg assembly against the ground, said third motive means of said lifting leg assemblies and said second motive means of said boom and bucket assembly being operable separately but cooperatively to engage all three of said bucket and said laterally projecting leg assemblies with the ground to lift said wheel means on said frame means to a height spaced above the ground, whereupon said first motive means connected between said rail carriage and said rail means can be operated separately to move said frame means relative to said rail carriage to thereby move said wheel means to a different location.