Dual hydraulic braking systems for vehicles

A pressure differential warning actuator comprising detector means for detecting when a differential between the pressures of separate brake circuits of an hydraulic braking system exceeds a predetermined value, a housing provided with a bore, said detector means positioned in said bore, said housing also provided with ports connected to said separate brake circuits, and indicator means actuated by said detector means when said predetermined value is exceeded, said detector means comprising at least a first and a second piston, said pistons working in separate bore portions of said bore, pressure from said separate brake circuits being connected through said ports to said pistons, means for moving said pistons between a neutral position in which said indicator means is rendered inoperative when said differential pressure is less than said predetermined value, and an operative position in which said indicator means is rendered operative when said differential pressure exceeds said predetermined value, and a deformable assembly through which said pistons act and which is adapted to restore said pistons from said operative position to said neutral position when said differential pressure decreases to a value less than said predetermined value, wherein said housing is provided with a chamber of increased diameter which interconnects said separate bore portions, said deformable assembly is located in said chamber, and reduced diameter portions are provided at the ends of said pistons adjacent to said deformable assembly and within said chamber, sleeves being provided on said reduced diameter portions, and shoulders being provided at each end of said chamber with which said sleeves engage.

A pressure differential warning actuator comprising detector means for detecting when a differential between the pressures of separate brake circuits of an hydraulic braking system exceeds a predetermined value, a housing provided with a bore, said detector means positioned in said bore, said housing also provided with ports connected to said separate brake circuits, and indicator means actuated by said detector means when said predetermined value is exceeded, said detector means comprising at least a first and a second piston, said pistons working in separate bore portions of said bore, pressure from said separate brake circuits being connected through said ports to said pistons, means for moving said pistons between a neutral position in which said indicator means is rendered inoperative when said differential pressure is less than said predetermined value, and an operative position in which said indicator means is rendered operative when said differential pressure exceeds said predetermined value, and a deformable assembly through which said pistons act and which is adapted to restore said pistons from said operative position to said neutral position when said differential pressure decreases to a value less than said predetermined value, wherein said housing is provided with a chamber of increased diameter which interconnects said separate bore portions, said deformable assembly is located in said chamber, and a reduced diameter portion is provided at the end of said first piston adjacent to said deformable assembly and within said chamber, a sleeve being provided on said reduced diameter portion, and shoulders are provided at each end of said chamber, said sleeve engaging one of said shoulders and said deformable assembly engaging the other of said shoulders.