Abstract: A device for varying the angular setting of the blade of an earthmoving vehicle by means of a pair of double acting hydraulic cylinders in which only one of the cylinders receives pressure direct from a pump. The piston of that cylinder acts on one end of the blade and at the same time transmits pressure fluid through a hydraulic circuit to the piston of the other cylinder acting on the other end of the blade whereby the two pistons move in opposite directions. The hydraulic circuit includes a control valve for reversing the direction of movement of the pistons, the same cylinder being pressurized by the pump in both directions of movement of the pistons. Pressure fluid leakage loss compensating means are provided in each piston.

Abstract: A device for indicating the presence of electrically conducting particles, such as metal detritus, in a liquid such as hydraulic oil passing through a filter in which a gap is provided adjacent the filter into which metal particles are swept by the liquid flow to form a conducting bridge in an electrical circuit. In a preferred embodiment, an annular gap closed to through flow is provided between an insulated metal ring around a filter element and the wall of the flow passage surrounding the filter, and the ring and the wall are connected to an electrical circuit for actuating a warning light or audible alarm when the gap is bridged.