Abstract: An improved shear-type pressure relief device is provided which is useful in conjunction with pressure chambers requiring relief when system pressures exceed a predetermined level, such as in the shock absorbing piston and cylinder assemblies of present day vehicle bumpers. The relief device is preferably in the form of an integral, metallic body including a flange in engagement with a pressure chamber wall adjacent a relief opening, with a projection extending into the opening. The juncture between the flange and projection is advantageously very sharp (having a radius of less than about 0.020 inches) and the device is designed to shear upon experiencing high system pressures for relief purposes. In the case of vehicle bumpers the shear device is located on the shiftable, bumper-mounted piston thereof, and circumscribes the usual stationary, tapered, frame-mounted, flow-restricting rod.

Abstract: An improved construction is provided for fluid pressure responsive electrical switching apparatus, which achieves physical miniaturization, quick response time, sensitivity to relatively low levels of change or differential in fluid pressures, adaptability for employment in corrosive environments and under a very wide range of temperature conditions, simplicity and economy of fabrication and assembly, reliability of operation and general versatility for utilization in diverse applications. The improved apparatus involves, besides suitable housing structure that may provide for installation accommodating to various pressure and other conditions dictated by the application, a thin, wafer-like laminated switch assembly peripherally sealed in the housing structure and disposed for direct fluid communication with the fluid whose pressure is to be monitored for the purpose of controlling actuation of the switch assembly.

Abstract: A non-fragmenting, low burst pressure rupture device assembly is provided for mounting between opposed flange members which define a relief orifice for a pressurized line or vessel. The assembly includes a relatively thin, flexible, fluid impervious sealing element adapted to be carried by the flange members in fluid blocking relationship to the orifice, along with a support member adapted to be mounted in supporting relationship to the element downstream of the pressure line or vessel. The support member has a series of relieved areas therein defining a closed loop pattern presenting a section which gives way or opens under a pre-determined pressure thereon applied through the sealing element from the pressurized area. The element has an integral bulge defining part overlying the perimeter of the section which allows the section of the support member to sense the pressure in the line or vessel through the sealing element independent of the burst pressure characteristics of the sealing element.