Abstract: A trenching apparatus, includes a body moveable on the ground surface, a ground engagement boom associated with the body, the boom being movable when engaged with the ground to form a trench; a lifting system arranged to control and configure the ground engagement boom so as to enter the ground; in which the ground engaging boom is an endless chain ground-engaging boom, including a main body and a chain tensioner coupled to the main body at or close to the upper end thereof.

Abstract: Trenching apparatus comprises a cutting device, preferably an endless chain cutter, mounted on a prime mover for positioning the cutting device in a trench with the prime mover movable on the ground surface above the level of the trench. Where the cutting device is a chain cutter, the boom projects forwardly and downwardly relative to the direction of cutting the trench, and drive unit arranged to drive the chain in a direction to carry the cutting elements upwardly around the distal end of the boom and rearwardly along the upper run of the endless chain cutter. In operation the distal end of the chain cutter is positioned against the end face of the trench at the bottom of the trench; the prime mover moves the chain cutter forwardly in the trench while operating the chain cutter, so as to produce an undercut in the end face of the trench; and the lifting device lifts the cutting device upwardly from the undercut through the material of the end face so as to cut material from the end face of the trench.

Abstract: Trenching apparatus comprises a cutting device, preferably an endless chain cutter, mounted on a prime mover for positioning the cutting device in a trench with the prime mover movable on the ground surface above the level of the trench. Where the cutting device is a chain cutter, the boom projects forwardly and downwardly relative to tho direction of cutting the trench, and drive means are arranged to drive the chain in a direction to carry the cutting elements upwardly around the distal end of the boom and rearwardly along the upper run of the endless chain cutter. In operation the distal end of the chain cutter is positioned against the end face of the trench at the bottom of the trench; the prime mover moves the chain cutter forwardly in the trench while operating the chain cutter, so as to produce an undercut in the end face of the trench; and the lifting means lifts the cutting device upwardly from the undercut through the material of the end face so as to cut material from the end face of the trench.

Abstract: Excavating apparatus includes a vehicle having excavator in the form of a pivotal cutting boom pivotably mounted on the vehicle. The cutting boom has an endless cutting clain drivingly mounted thereon and the boom is pivoted relative to the vehicle so as to vary the depth to which a trench is current. In seeking to cut a trench having a level floor irrespective of any undulations in the surface upon which the vehicle travels, a sensor is associated with the apparatus and is arranged to receive a reference signal. Any variation in the location at which the reference signal impinges on the sensor, for instance due to the passage of the vehicle up an incline, serves to determine the angle at which the cutting boom extends from the vehicle and so varies the depth to which the trench is cut.

Abstract: A pipe laying machine comprises a vehicle carrying a trench excavator followed by a pipe laying box running in the trench. Pipe lengths are stored in the pipe laying box one above another and the lowermost pipe length is periodically released by movement of bars into the bottom of the pipe laying box and is pressed by a ram into the mouth of the last laid pipe length.

Abstract: Excavating apparatus includes a vehicle having excavating means in the form of a pivotal cutting boom pivotably mounted by way of mounting means on the vehicle. The cutting boom has an endless cutting clain drivingly mounted thereon and the boom is pivoted relative to the vehicle so as to vary the depth to which a trench is current. In seeking to cut a trench having a level floor irrespective of any undulations in the surface upon which the vehicle travels, a sensor is associated with the apparatus and is arranged to receive a reference signal. Any variation in the location at which the reference signal impinges on the sensor, for instance due to the passage of the vehicle up an incline, serves to determine the angle at which the cutting boom extends from the vehicle and so vary the depth to which the trench is cut.