Bucket mounting for trench hoe

Claim 1

A trench hoe comprising a digging bucket, a triangular shift lever having one arm pivoted to the inner end of said bucket, a front hydraulic thrust piston drive having a piston rod pivoted to the apex of said shift lever, a dipper arm at one side of said shift lever and pivoted at its outer end to said bucket inner end and in spaced relation to the pivotal connection of said shift lever and said bucket, a pivotal connection between the other arm of said shift lever and said dipper arm in close spaced relation to said pivotal connection between said dipper arm and bucket, a ground outrigger arm, means providing a pivotal connection between the outer end of said outrigger arm and the inner end of said front thrust piston drive, means providing a pivotal connection between said outrigger arm and said dipper arm in close spaced relationship to the pivotal connection means between said thrust piston drive and said outrigger arm and at the other side of said triangular shift lever, and L-shaped inner end portion on said dipper arm, a rear hydraulic thrust piston drive connected to the end of said L-shaped inner end portion of said dipper arm and disposed above said ground outrigger arm, the arrangement being such that a trapezoid control lInkage for said digging bucket is provided consisting of said bucket, said dipper arm, said front thrust piston drive, and the partial length of said ground outrigger arm between said dipper arm axis and the adjacent pivotal connection of said front thrust piston drive, and said control linkage being so dimensioned in relation to the dimensions of said outrigger arm that said digging bucket is guided in operation approximately parallel to its starting position by tilting it about its pivotal mounting during digging action under a desired angle of slope or gradient within a predetermined range of angles of slope or gradient.