Abstract: A mechanized unit is provided for digging a trench in the ground and laying elongate objects in the trench, including a motor driven vehicle, a digging wheel connected to the rear of the vehicle, and a reserve connected to the front of the vehicle and containing said elongate objects, and a guide device for laying said objects in the vicinity of the bottom of the trench, the device being connected to the vehicle, said mechanized unit further including a receptacle connected to the vehicle and containing a fine powdery material and means for feeding said material from the receptacle to the guide device so that, during formation of the trench by the digging wheel, said elongate objects are buried in the fine powdery material deposited in said trench.

Abstract: A trenching wheel more especially for digging trenches, of the type in which the tools are mounted on ring portions removably fixed to the periphery of said wheel. The arrangement for fixing each ring portion to the periphery of said wheel include:a first assembly of two end faces provided respectively at the ends of said ring portiona second assembly of two abutment faces fixed to the periphery of said wheel and orthogonal to the plane thereof; anda wedge shaped key insertable from outside the periphery of said wheel inwardly thereof, between an end face of said first assembly and an abutment face of said second assembly for applying the other of said end faces of said first assembly under pressure against the other of said abutment faces of said second assembly.