Patent ID: 7654017

Claim:
A trenching attachment for selective attachment to a working machine, the trenching attachment comprising: a frame arranged for selective connection to the working machine; an internal combustion engine mounted to the frame; a fuel tank carried on the frame and operably connected to the internal combustion engine to deliver fuel thereto; an electric starter carried on the frame and operably connected to the internal combustion engine to effect starting thereof; a battery power supply carried on the frame and coupled to the electric starter to provide power thereto for starting the engine; a charging system associated with the engine and coupled to the battery power supply to effect charging thereof under operation of the engine; a boom arm carried on the frame at a connection end of the boom arm and pivotal about a pivot axis transverse to the frame at the connection end of the boom arm; an actuator carried on the frame and operable to effect pivoting of the boom arm to effect raising and lowering of a distal end of the boom arm opposite the connection end thereof relative to the frame; a drive sprocket supported adjacent the connection end of the boom arm and rotatable about a rotational axis parallel to the pivot axis of the boom arm; an idler sprocket supported on the boom adjacent a distal end thereof opposite the connection of the boom arm to the frame and rotatable about an idler axis parallel to the rotational axis of the drive socket; a trencher chain entrained about the drive sprocket and idler sprockets; a gear box having an input gear coupled to a belt driven sheave and an output gear coupled with a driven shaft extending along the pivot axis of the boom arm to effect rotation of the driven shaft under rotation of the output gear, the drive sprocket being coupled to the driven shaft to be rotationally driven thereby to operate the trencher train; a belt driving sheave coupled to an output shaft of the engine for driven rotation thereby; a belt closing around the belt driving sheave and the belt driven sheave; a clutch installed on the frame and operable by an operator of the attachment to add and remove tension of belt around the belt driving and belt driven sheaves to selectively start and stop driven rotation of the belt driven sheave and the input and output gears of the gear box with the engine running; and a dead man's switch operable to cease operation of the trenching chain under a lack of input at the dead man's switch from the operator of the attachment, the dead man's switch being movable relative to the frame of the attachment and operable at a distance therefrom for enabling use of the dead man's switch from an operator position at the working machine.