Abstract: An annular seat structure, for use in subterranean well stimulation operations, is operative in conjunction with associated expansion control structure to permit a predetermined number of fracture plug members to axially pass therethrough. In an illustrated embodiment thereof, the annular seat structure is movable between a retracted position having a first interior diameter, and a resiliently expanded position having a second, larger interior diameter. The seat structure has an annular array of rigid ring segments interdigitated with annular gaps that receive radially outwardly projecting portions of an annular resilient liner secured to radially inner surfaces of the rigid ring segments, the outwardly projecting liner portions being secured to circumferentially facing surfaces of the rigid ring segments. An annular spring member coaxially circumscribes the rigid ring segment array, is received in notches formed in the rigid segments, and resiliently biases the seat structure toward its retracted position.

Abstract: An annular seat structure, for use in subterranean well stimulation operations, is operative in conjunction with associated expansion control structure to permit a predetermined number of fracture plug members to axially pass therethrough. In an illustrated embodiment thereof, the annular seat structure is movable between a retracted position having a first interior diameter, and a resiliently expanded position having a second, larger interior diameter. The seat structure has an annular array of rigid ring segments interdigitated with annular gaps that receive radially outwardly projecting portions of an annular resilient liner secured to radially inner surfaces of the rigid ring segments, the outwardly projecting liner portions being secured to circumferentially facing surfaces of the rigid ring segments. An annular spring member coaxially circumscribes the rigid ring segment array, is received in notches formed in the rigid segments, and resiliently biases the seat structure toward its retracted position.

Abstract: An annular seat structure, for use in subterranean well stimulation operations, is operative in conjunction with associated expansion control structure to permit a predetermined number of fracture plug members to axially pass therethrough. In an illustrated embodiment thereof, the annular seat structure is movable between a retracted position having a first interior diameter, and a resiliently expanded position having a second, larger interior diameter. The seat structure has an annular array of rigid ring segments interdigitated with annular gaps that receive radially outwardly projecting portions of an annular resilient liner secured to radially inner surfaces of the rigid ring segments, the outwardly projecting liner portions being secured to circumferentially facing surfaces of the rigid ring segments. An annular spring member coaxially circumscribes the rigid ring segment array, is received in notches formed in the rigid segments, and resiliently biases the seat structure toward its retracted position.

Abstract: A fracture plug seat assembly used in well stimulation for engaging and creating a seal when a plug, such as a ball, is dropped into a wellbore and landed on the fracture plug seat assembly for isolating fracture zones in a well. The fracture plug seat assembly has a fracture plug seat that includes elastomeric material and reinforcing material.

Abstract: An annular seat structure, for use in subterranean well stimulation operations, is operative in conjunction with associated expansion control structure to permit a predetermined number of fracture plug members to axially pass therethrough. In an illustrated embodiment thereof, the annular seat structure is movable between a retracted position having a first interior diameter, and a resiliently expanded position having a second, larger interior diameter. The seat structure has an annular array of rigid ring segments interdigitated with annular gaps that receive radially outwardly projecting portions of an annular resilient liner secured to radially inner surfaces of the rigid ring segments, the outwardly projecting liner portions being secured to circumferentially facing surfaces of the rigid ring segments. An annular spring member coaxially circumscribes the rigid ring segment array, is received in notches formed in the rigid segments, and resiliently biases the seat structure toward its retracted position.

Abstract: Alternate embodiments of a vehicle tire inflation system are illustrated wherein pressurized air from a source on the vehicle is supplied from an end of an axle to the rotating hub cap and thus to the tire through a flexible tube which compensates for misalignment of the axes of the axle and hub cap.

Abstract: Alternate embodiments of a vehicle tire inflation system equipped with a low tire pressure warning device are illustrated wherein a pressure regulating valve controls the pressure delivered to the tires from a pressurized air source and has an integrated electrical switch to indicate if the pressure regulating valve is supplying air to a tire.

Abstract: Alternate embodiments of a vehicle tire inflation system are illustrated wherein pressurized air from a source on the vehicle is supplied from an end of an axle to the rotating hub cap and thus to the tire through a flexible tube which compensates for misalignment of the axes of the axle and hub cap.

Abstract: There are disclosed several embodiments of a disc brake caliper assembly in which adjustment is made for wear on the pads by a non-rotating linearly expandable and retractable linkage arranged between a brake actuator and the pads. The linkage includes inner and outer members coaxially reciprocal without rotation with respect to one another, one member having surfaces which extend at acute angle with respect to the axis and opposite surfaces on the other member which extend parallel to the axis. Circumferentially spaced wedges are disposed in the space between the angled and parallel surfaces, and springs between the first member and wedges yieldably urge the wedges in the first longitudinal direction toward the angled surfaces, the second member being movable during the braking cycle in a second longitudinal direction and thus relatively to the first member, whereby the linkage is caused to expand in order to adjust for wear.

Abstract: Disclosed is an air-applied, mechanically-held brake assembly and a vehicle air brake system employing the same. The air brake system typically includes a push-pull or hand-brake valve for park and emergency applications, a treadle valve for service applications, reservoirs of air under pressure, and other valving and plumbing. The brake assembly applies and releases the brake upon the supply and exhaust, respectively, of air from a first pressure chamber. The brake assembly locks and unlocks the brake in an applied position by the exhaust and supply, respectively, of air from a second pressure chamber. The locking mechanism of the brake assembly is designed to compound the force of the fluid pressure in the first pressure chamber with the force of the fluid pressure supplied to the second pressure chamber when unlocking the brake to compensate for back pressure.

Abstract: Disclosed is an air-applied, mechanically-held brake assembly and a vehicle air brake system employing the same. The brake assembly applies and releases the brake upon the supply and exhaust, respectively, of air from a first pressure chamber. The brake assembly locks and unlocks the brake in an applied position by the exhaust and supply, respectively, of air from a second pressure chamber. The locking mechanism of the brake assembly is designed to compound the force of the fluid pressure in the first pressure chamber with the force of the fluid pressure supplied to the second pressure chamber when unlocking the brake to compensate for back pressure.