Abstract: A hydraulic actuator which may be used as a surge brake actuator may include a housing defining a low pressure chamber and a high pressure chamber, a low pressure piston assembly which is in the low pressure chamber and has a contact surface, a high pressure piston assembly which is in the high pressure chamber and which moves forward in response to forward movement of the low pressure piston assembly, and an unloader valve in fluid communication with the low pressure chamber and having a closed position and an open position adapted to allow hydraulic fluid to flow out of the low pressure chamber through the unloader valve, wherein the contact surface engages and pushes the unloader valve from the closed position to the open position during forward movement of the low pressure piston assembly. The actuator may be used for actuating a brake system.

Abstract: A high order of thermal efficiency is achieved in a steam engine or steam expander having a piston clearance that approximates zero together with a negligible amount of compression, such that pressure in the clearance volume approximates ambient pressure, i.e. atmospheric or condenser pressure as the case may be at the end of the piston return stroke when the clearance is essentially zero and constitutes a new engine apparatus and Rankine operating cycle that can be referred to as “zero clearance with zero compression”. The steam admission valve assembly can be operated either automatically responsive to piston contact or by means of a cam shaft or electrically by means of a solenoid. A normally open exhaust valve permits residual steam to be exhausted through the piston return stroke, closed by the piston or cam then held closed by a fresh charge of steam.

Abstract: A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill.

Abstract: In an artificial leg for a person having an upper thigh cut and a knee joint lost, a cylinder disposed between upper and lower leg members, which are coupled through a pivotable joint, for controlling bending and straightening of the joint by an air cushion for convenience of walking. The cylinder includes a cylindrical sleeve closed at both ends and a piston having a piston rod and sliding in the sleeve, and has its structure improved by using as a cushion one of two inner cavities separated by the piston, which encloses the piston rod, thereby buffering butting between the upper and lower leg members to remove unpleasant shock resulting at the end of straightening the joint.

Abstract: A linear hydraulic motor including a first piston rod (12) and piston head (16), a second piston rod (18) and piston head (26), and a cylinder housing (30), having a divider wall (46), adapted to reciprocate longitudinally on the piston heads (16, 26). The cylinder housing (30) has end members (34, 36) through which piston rods (12, 18) extend. Four fluid chambers (52, 54, 56, 58) are formed within the linear hydraulic motor. Fluid chambers (52, 56) communicate with each other through conduits (62), and fluid chambers (54, 58) communicate with each other through conduit (64). Piston rods (12, 18) include conduits (68, 70) for fluid communication with chambers (54, 56). A snubber (74) is provided in the divider wall (46) of the cylinder housing (30). The snubber (74) reciprocates within the divider wall (46) and is adapted to abut the inner ends of the piston rods (12, 18) as the divider wall (46) approaches piston heads (16, 26) during the reciprocating process.

Abstract: In combination with a transmission having a multiple input portion and a multiple output portion, each of which contains a plurality of speed change gears, is a shift control system having a plurality of fluid-pressure operated actuators that respond to movement of a preselector valve control member having a plurality of positions that correspond to separate ones of the drive ratios. Shift sensing means produce a first signal upon movement of the preselector valve control member whereas neutral position sensing means produce a second signal upon movement to neutral of the transmission input portion. A neutral sequence valve has a movable spool member maintainable in first and second alternate positions in response to the first and second signals, with mechanical interlock means, associated with the actuators, locking the transmission output portion in gear whenever the transmission input portion is in gear and locking the input portion in neutral whenever the output portion is in neutural.