A joint cushioning system includes a pad of a foam material which is resiliently compressible. The pad has an outer surface, an inner surface, an upper edge, a lower edge, a first lateral edge and a second lateral edge. A magnetorheological fluid impregnates the foamed material. The magnetorheological fluid is configured to be alternated between a first state wherein the foamed material is bendable and compressible and a second state wherein the magnetorheological fluid forms rigid columns within the foamed material such that the foamed material is less bendable and compressible. An actuating system is mounted on the pad and is in operational communication with magnetorheological fluid. The actuating system actuates the magnetorheological fluid from the first state to the second state when a condition has been met.

Disclosed are a compound impact-resistant device and an application thereof. The compound impact-resistant device includes an inner cylinder, a first pressure sensor and an outer cylinder; an inner cavity of the inner cylinder is connected to a magnetorheological damper, a spiral valve element, a floating piston and a spring from bottom to top; and the outer cylinder is connected to a piston rod, a bottom end of the piston rod penetrates a top of the inner cylinder, the spring and the floating piston to be connected to the spiral valve element, and a portion below the spiral valve element is filled with hydraulic oil. The compound impact-resistant device can provide specific initial support force and achieve active self-adaptation to dynamic impact, thus solving the problems that traditional hydraulic buffers cannot provide initial support force and traditional mechanical crushing members have difficulty in providing large support force.

An aircraft landing gear shock absorbing strut having an outer cylinder and a sliding tube coupled within the cylinder bore to move between compressed and extended conditions. The cylinder and tube define a variable-volume internal chamber. The internal chamber is divided into a first spring chamber and a second spring chamber. The first spring chamber is a pneumatic chamber containing a first gas that is compressed when the strut moves from the extended condition to the compressed condition to provide compression damping. The second spring chamber contains a second gas and a hydraulic liquid, and is configured to compress the second gas when the strut moves from the extended condition to the compressed condition. The second spring chamber contains one or more damping orifices through which the oil passes as the strut extends to provide recoil damping during extension of the strut.

Housing has first and second parallel tubular chambers. The first chamber contains a gas spring whose output shaft connects to a first piston of area A.sub.1. The second chamber contains a second piston of area A.sub.2<A.sub.1. Piston A.sub.2 connects to the device's output shaft. The housing has a valve block with an internal port in fluid communication with the two chambers between the first and second pistons. The valve block contains an incompressible fluid. A poppet valve is in the internal port. The poppet includes a flow restricting bore therethrough. A force on the output shaft causes the fluid to force open the poppet and displace the piston, A.sub.1, storing energy in the gas spring. Upon removal of the force on the device's output shaft, the gas spring pushes the fluid to close the poppet. Hence, only a low volume flow through the bore in the poppet is permitted.

A structure having limited supportable portions has been difficult to isolate from vibration in the direction in which a load is applied. A base isolation apparatus includes a Z-axis base isolation unit, an X-axis base isolation unit, and a Y-axis base isolation unit. The base isolation unit includes a vibration-source connector, an isolated-object connector, a lock device disposed between the isolated-object connector and the vibration-source connector for switching between a state of fixing the isolated-object connector and a state of making it movable, a distance recovery device for generating a force to cause an amount of change in distance to approach zero, depending on the amount of change, and a vibration damper for generating a force in an orientation of hindering the change, depending on the rate of change in distance.

A damping stopper is interposed between two members axially displaced relative to each other and is provided with an elastic body which, when the interval between the two members decreases, is axially compressed by the two members and expands radially outward. In the elastic body, a second member suppressing the expansion is located in one axial region and attached to the outer periphery. When axially compressed by the two members, the elastic body expands while receiving resistance by the second member. The expanding elastic body contacts the side wall of one of the two members.

A joint cushioning system includes a pad of a foam material which is resiliently compressible. The pad has an outer surface, an inner surface, an upper edge, a lower edge, a first lateral edge and a second lateral edge. A magnetorheological fluid impregnates the foamed material. The magnetorheological fluid is configured to be alternated between a first state wherein the foamed material is bendable and compressible and a second state wherein the magnetorheological fluid forms rigid columns within the foamed material such that the foamed material is less bendable and compressible. An actuating system is mounted on the pad and is in operational communication with magnetorheological fluid. The actuating system actuates the magnetorheological fluid from the first state to the second state when a condition has been met.

A method and apparatus for activating a vehicle's brake pedal for testing proper operation of the vehicle's brake lights and/or for testing for an air leak in the vehicle's air brake system. The method and apparatus can be advantageously employed by a single operator of the vehicle without need for assistance from another person.

A dual-stage, separated gas/fluid shock strut arrangement includes a dual-stage, separated gas/fluid shock strut, a pressure/temperature sensor mounted to the primary gas chamber, a stroke sensor, and a monitoring system, comprising a recorder configured to receive a plurality of sensor readings from at least one of the pressure/temperature sensor and the stroke sensor, a landing detector configured to detect a landing event based upon a stroke sensor reading received from the stroke sensor, and a health monitor configured to determine a volume of oil in the oil chamber, a volume of gas in the primary gas chamber, and a volume of gas in the secondary gas chamber.

A dual-stage, separated gas/fluid shock strut arrangement includes a dual-stage, separated gas/fluid shock strut and a monitoring system. The shock strut includes a strut cylinder, a strut piston operatively coupled to the strut cylinder, an oil chamber, a primary gas chamber, and a secondary gas chamber. The monitoring system includes a first pressure/temperature sensor, a second pressure/temperature sensor, a stroke sensor, a recorder configured to receive a plurality of sensor readings from the first pressure/temperature sensor, the second pressure/temperature sensor, and/or the stroke sensor, a landing detector configured to detect a landing event based upon a stroke sensor reading received from the stroke sensor, and a health monitor configured to determine a volume of oil in the oil chamber, a primary chamber gas volume in the primary gas chamber, and a secondary chamber gas volume in the secondary gas chamber.