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 center support member for a tiltable swivelling grading blade on an earthmoving machine which prevents the occurence of internal stresses in the blade generated by tilting of the blade is in the form of a ball and socket joint attached to the center rear of the blade and to a carrier frame on the machine. A shaft slidable in a sleeved mounting carries the ball portion of the joint at one end and the other end of the shaft is spring urged towards the blade by spring means in the sleeved mounting. Stop means in the sleeved mounting limit the stroke of the shaft. Additionally, a piston engaged by the spring means in a chamber in the sleeved mounting is arranged to force lubricant through a feed line to the shaft in response to axial movement of the shaft.

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.