| 主权项 |
1. A trencher (10) comprising:
a chassis (12) having a front end (14) and a back end (16); a propulsion system (18) for moving the chassis (12) forward and rearward; a trencher boom (20) mounted to the back end (16) of the chassis (12), the trencher boom (20) being pivotally movable relative to the chassis (12) between a raised position and a lowered position, the trencher boom (20) including proximal end (22) pivotally mounted to the chassis (12) and a distal end (24), the trencher boom (20) defining a longitudinal axis that extends between the proximal and distal ends (22, 24) of the boom (20), the trencher boom (20) also including a boom frame (26) that extends longitudinally along the longitudinal axis of the boom (20), the trencher boom (20) having a top side (28) and a bottom side (30); the trencher boom (20) including a first trenching portion at the distal end (24) of the boom (20) and a second trenching portion that extends along the longitudinal axis from the first trenching portion toward the proximal end (22), the first trenching portion defining a first trench width and the second trenching portion defining a second trench width, the first trench width being larger than the second trench width, the first trenching portion having a length measured along the longitudinal axis that is less than one half of a total length of the trencher boom (20); the trencher boom (20) including a trenching chain (34) that moves along a continuous path that extends around a length of the boom frame (26), the trenching chain (34) defining a chain width that corresponds to the second trench width, the chain (34) turning about a first axis (L1) at the proximal end (22) of the boom (20) and a second axis (L2) at the distal end (24) of the boom (20); the trencher boom (20) including first and second trench wideners (32) positioned at the distal end (24) of the trencher boom (20) on opposite sides of the trenching chain (34), the first and second trench wideners (32) being configured to rotate about the second axis (L2) as the chain (34) is driven along the continuous path, the first and second trench wideners (32) cooperating to define outer extents of the first trench width, and each of the first and second trench wideners (32) having a cutting width that is less than 0.75 times as large as the chain width; the trenching chain (34) including a main chain body and a plurality of chain cutters (38) carried with the main chain body, wherein the chain cutters (38) are oriented such that tips of the chain cutters (38) face at least partially in a rearward direction when the chain cutters (38) are traveling along the top side (28) of the trencher boom (20) and face at least partially in a forward direction when the chain cutters (38) are traveling along the bottom side (30) of the trencher boom (20); and the first and second trench wideners (32) respectively including first and second drum sections (36) carrying a plurality of drum cutters (41), wherein the drum cutters (41) are oriented such that tips of the drum cutters (41) face at least partially in the rearward direction when the drum cutters (41) are directly over their respective first and second drum sections (36) and face at least partially in the forward direction when the drum cutters (41) are directly under their respective first and second drum sections (36); wherein during operation, the trencher (10) draws the spoils up along the bottom side (30) of the boom (20). |
