Abstract: A safety valve of the type that includes a sleeve (1) with a high pressure port (11) and a low pressure port (12); a valve seat (2) and a poppet (3), both slidably inserted in the sleeve and adapted to be brought together to provide a valve interface that is capable of establishing and blocking a fluid communication between the high pressure port and the low pressure port; and a spring (7) adapted to force the poppet against the valve seat, wherein a difference in force between a fluid pressurized in the high pressure port acting on a pressure receiving surface of the poppet and the spring acting against said pressurized fluid urges the poppet to open the valve interface, thereby relieving the high pressure port by a portion of the pressurized fluid admitted out thereof into the low pressure port.

Abstract: There is provided a hydraulic braking apparatus, characterized in that it comprises: a first safety valve for draining a high pressure fluid at the side of a second port of a hydraulic motor into the side of a first port thereof; a second safety valve for draining a high pressure fluid at the side of the said first port of the said hydraulic motor into the side of the said second port thereof; and a braking valve adapted to be switched from a neutral position to a first position or a second position under a difference in pressure between the said first port and the said second port, the inlet side of each of the said first safety valve and the said second safety valve having a communication via the said braking valve with the side of each of the said first port and the said second port, and having an increased area of such communication when the said braking valve is set in the said neutral position and a reduced area of such communication when the braking valve is switched to the said first position or to th

Abstract: In a piston pump/motor of swash plate type which comprises: a cylinder block disposed in a casing to be rotatable jointly with a shaft therein; a plurality of pistons slidably inserted in the cylinder block parallel to the shaft; and a swash plate swingably attached to the casing for guiding the plurality of pistons on a front surface thereof and changing a displacement of each of the pistons by changing an inclination thereof, there is provided a swash plate angle changing apparatus in which the swash plate has a rear surface formed with a first contact surface and a second contact surface which make an angle between them. The casing has a swash plate support surface which is perpendicular to the shaft and with which the first contact surface and the second contact surface are each adapted to contact.