Abstract: A combination check valve and relief valve has a valve body with an inlet, an outlet, and a valve chamber operatively interposed between the inlet and outlet. A check valve may be integrated with the relief valve and therefore simplify a hydraulic system. The valve includes a relief valve member which is within the valve chamber. The valve also includes a resilient member with a first end and a second end. The first end of the resilient member operatively engages the relief valve member. The valve includes a setting member pressure-fit within the valve chamber to operatively engage the second end of the resilient member. The resilient member is resiliently biased between the setting member and the relief valve member to bias the relief valve member against a relief valve seat, whereby, when pressurized fluid communicates with the inlet, the resilient member is compressed, and the relief valve member disengages its seat to enable the fluid to pass through to the outlet.

Abstract: A method for configuring a hydraulic actuator to provide energy dissipation capabilities during low energy collisions while controlling energy dissipation during high energy collisions comprises biasing a valve member towards a closed position with a resilient member having a rigidity of between 600 and 1500 lbs/in, applying a low preload to the resilient member, and restricting the flow of fluid by using a stop to limit movement of the valve member away from the closed position.

Abstract: In accordance with an aspect of the present invention, there is provided a photoelastic coating for structural monitoring comprising an optically translucent or transparent photoelastic layer. The photoelastic coating is applied to the structure as a solvent-based liquid or gel that can be cured without heating. The photoelastic properties of the photoelastic layer can be used to detect stress and strain or plastic deformation in the structure using photoelastic techniques. In accordance with another aspect of the invention, there is provided a method of structural monitoring using a photoelastic structural monitoring coating. The method comprises the steps of providing a structure for which structural monitoring is desired, applying a photoelastic layer to said structure as a solvent-based liquid or gel, and curing said photoelastic layer in place on said structure.

Abstract: In accordance with the present invention, a photoelastic layer for detecting stress and strain is described. The photoelastic layer comprises a photoelastic material that when strained refracts light anisotropically. The photoelastic layer further comprises an integrated polarizer attached on top of the photoelastic material. Also in accordance with the present invention, a photoelastic monitoring device is described for structural monitoring. The photoelastic monitoring device is made out of a photoelastic material or comprises a photoelastic material attached to a base material. The photoelastic monitoring device further comprises an integrated polarizer attached or coated directly over at least a portion of the photoelastic material. The photoelastic monitoring device is designed to be attached to a structure or a part. The monitoring device is attached to the structure in such a way that stresses and strains from the structure are transmitted into the photoelastic monitoring device.

Abstract: The present invention provides a monitoring device for detecting stresses and strains in structural components and a method of using the monitoring device. The monitoring device comprises a base material, one or more attachment points for attaching the monitoring device to a structure to be monitored, a detection zone on the monitoring device, and a means for detecting the presence of stress and strain in the detection zone. The dimensions and material of the monitoring device are chosen such that a predetermined level of strain transmitted to the monitoring device from the structure will result in a known level of stress and strain in the detection zone. Detection of stress and strain in the detection zone can be correlated to a level of stress and strain experienced by the structure at the point of attachment of the monitoring device.

Abstract: A combination check valve and relief valve has a valve body with an inlet, an outlet, and a valve chamber operatively interposed between the inlet and outlet. A check valve may be integrated with the relief valve and therefore simplify a hydraulic system. The valve includes a relief valve member which is within the valve chamber. The valve also includes a resilient member with a first end and a second end. The first end of the resilient member operatively engages the relief valve member. The valve includes a setting member pressure-fit within the valve chamber to operatively engage the second end of the resilient member. The resilient member is resiliently biased between the setting member and the relief valve member to bias the relief valve member against a relief valve seat, whereby, when pressurized fluid communicates with the inlet, the resilient member is compressed, and the relief valve member disengages its seat to enable the fluid to pass through to the outlet.

Abstract: A hydraulic actuator comprises a cylinder, a piston reciprocatingly received within the cylinder, a piston rod connected to the piston and a pressure release mechanism which allows hydraulic fluid to pass from a first side of the piston to a second side of the piston when the actuator encounters shock loading. This permits the piston to move. The pressure relief mechanism includes a passageway extending from the first side of the piston to the second side of the piston and a valve member adjacent to the passageway which releasably engages the piston. The valve member has a closed position where the valve member closes the passageway and engages the piston. A resilient member biases the valve member towards the closed position. A valve member limiter limits movement of the valve member away from the closed position.

Abstract: A hydraulic actuator comprises a cylinder, a piston reciprocatingly received within the cylinder, a piston rod connected to the piston and a pressure release mechanism which allows hydraulic fluid to pass from a first side of the piston to a second side of the piston when the actuator encounters shock loading. This permits the piston to move. The pressure relief mechanism includes a passageway extending from the first side of the piston to the second side of the piston and a valve member adjacent to the passageway which releasably engages the piston. The valve member has a closed position where the valve member closes the passageway and engages the piston. A resilient member biases the valve member towards the closed position. A valve member limiter limits movement of the valve member away from the closed position.

Abstract: A hydraulic actuator comprises a cylinder, a piston reciprocatingly received within the cylinder, a piston rod connected to the piston and a pressure release mechanism which allows hydraulic fluid to pass from a first side of the piston to a second side of the piston when the actuator encounters shock loading. This permits the piston to move. The pressure relief mechanism includes a passageway extending from the first side of the piston to the second side of the piston and a valve member adjacent to the passageway which releasably engages the piston. The valve member has a closed position where the valve member closes the passageway and engages the piston. A resilient member biases the valve member towards the closed position. A valve member limiter limits movement of the valve member away from the closed position.