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, an outrigger arm, link means providing an articulated connection between the inner end of said front thrust piston drive and said dipper arm and said outrigger arm, a pivotal connection between said dipper arm and said outrigger arm and disposed at the other side of the dipper arm facing away from said triangular shift lever, the end portion of said dipper arm extending beyond said last pivotal connection, a rear hydraulic thrust piston drive connected to the end of said last end portion and disposed above said 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 said link means between said front piston drive and said dipper arm, 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 under a desired angle of slope or gradient within a predetermined range of angles of slope or gradient.