Abstract: An improved variable width screed device that attaches to an industrial vehicle, such as an excavator, having a push blade and controlled arm mechanism. The position of the controlled arm mechanism determines the width of the screed. The screed width can be instantaneously adjusted along a spectrum of widths by modifying the radial position of the controlled arm mechanism.

Abstract: A trenching attachment for selective attachment to a working machine features a frame arranged for selective connection to the working machine, an internal combustion engine mounted to the frame and a boom assembly connected to the frame and having a trencher chain installed thereon. The internal combustion engine is operatively connected to the trenching chain to facilitate driving thereof. Having its own dedicated engine, the trenching attachment is less dependent on the power take-off system of the working machine than a conventional trenching attachment that uses a hydraulic motor to power the trencher chain and relies exclusively on delivery of hydraulic fluid from the working machine for operation.

Abstract: A boom control circuit for controlling hydraulic fluid fed to a boom cylinder is provided separately and independently from a travel/stick/bucket control circuit, which serves to control hydraulic fluid fed to travel motors, a stick cylinder, and a bucket cylinder. The boom control circuit includes a boom pump, an energy recovery motor disposed in a return passage through which return fluid from the boom cylinder 8bmc passes, and a boom motor generator connected to the energy recovery motor. The aforementioned boom pump is connected through a clutch to the boom motor generator. The invention is capable of providing a work machine of which a boom control circuit is adapted to function independently so that the flow rate required by the boom control circuit can be easily ensured.

Abstract: A trencher includes a trencher frame mounting a chain bar in a cantilever manner with a safety guide overlying the chain bar. Both the chain bar and the safety guide are adjustable on the trencher frame between various laterally spaced positions with the safety guide being able to overlie the chain bar in the different laterally spaced positions. The chain bar comprises a mounting stub over which one end of an elongated boom may be inserted. The stub includes a central longitudinal slot for receiving bolts passing through the boom to secure the boom to the slot. The use of a longitudinal slot in the stub allows the height of the stub to be maximized relative to the height of the boom to provide a stronger and more durable mounting for the boom.

Abstract: A sprocket is disclosed for driving a chain with a plurality of chain rollers. The sprocket may be used to drive a material removal chain of a trencher. The sprocket has various cut-aways or reliefs on each face thereof to more effectively clear particulate debris from beneath chain rollers during cutting or digging operations. The sprocket also has asymmetrical teeth designed to help minimize changes in pitch diameter due to debris entrained beneath chain rollers. Reducing changes in pitch diameter greatly reduces premature wear of the sprocket and its chain. Reducing changes in pitch diameter also greatly reduces the tendency for the chain to bind.

Abstract: The present invention includes a trencher assembly with a motor that directly drives a sprocket through the rotation of a shaft of the motor. The rotation of the sprocket drives both a digging chain and an auger assembly simultaneously. The ability to use a motor to directly drive the sprocket decreases the components necessary for a drive train of the trencher assembly to promote a compact design. This occurs because the sprocket is able to drive both the digging chain and auger assembly through the transfer of driving forces from the motor without any intermediate gearing, belts, rotating support structure, and the like.