Abstract: The invention provides automated adjustment of the height of a trenching blade. There is a blade holder having a generally vertical channel defined therein, and support means for carrying the blade holder behind a vehicle at a height above the ground. A trenching blade for dragging through the ground behind the vehicle has a shank portion extending upwardly therefrom into the channel and slidably engaging in the channel for vertical movement therewithin, whereby the depth of the blade may be varied. At least one hydraulic cylinder is connected between the blade holder and the blade shank for varying the position of the blade shank within the blade holder and thereby varying the depth of the blade. In the preferred embodiment, the support means is at the end of a boom which is pivotally connected to the vehicle for pivotal movement about a generally vertical axis, and the blade holder is pivotally mounted to the support means, for pivotal movement about a generally vertical axis.

Abstract: A toilet tank fill valve assembly is disclosed, in which the tank water level at which the valve opens is different from the tank water level at which the valve closes. The valve has a substantially vertical rod, which moves up to activate a lever to allow the ballcock valve to close, and moves down to activate the lever to open the ballcock valve. The rod has upper and lower stops, preferably adjustable, corresponding to the valve closing and valve opening positions respectively. A float lifts the upper stop when the tank becomes full, thereby allowing the ballcock valve to close. A weight pushes the lower stop down when the tank becomes empty, thereby opening the ballcock valve. The float and weight may be separate units, or may be a single unit which rides up and down on the rod between the stops.