Abstract: A slitting or tenching tool is described comprising a blade adapted to be lowered vertically into the soil and pulled therethrough so as to define a slit or trench having a depth determined by the mean depth to which the blade penetrates the soil, in which a vibrator causes the blade to vibrate at least in a generally up and down manner at the same time as it is moved in a forward direction. A second blade may be provided which is oscillated in a backwards and forwards manner. The second blade includes wings at its lower end to form a horizontal slit which communicates with the vertical trench or slit formed by the first blade. The second blade may be hollow so that finely divided particulate material maybe dispensed therethrough into the trench for backfilling. A pipe or cable dispensing leg may be associated with the blades or situated between them. A tape may be fed into the horizontal slit formed by the second blade.

Abstract: An apparatus for excavating a trench comprises two blades which are spaced apart laterally and arranged to form two slits in the ground, and two laterally spaced excavating discs arranged one behind each blade to run substantially in the cut of the preceding blade and operable to grip spoil between the cuts and remove the spoil to form the trench.