Abstract: Ball screw rotary actuator with ball cage. In one embodiment, a ball screw rotary actuator includes an outer cylinder, a piston, and inner shaft. Outer ball bearings travel in helical groove between the outer cylinder and position to rotate the piston as it translates due to fluid pressure. The inner shaft is situated radially inward of the piston, and straight grooves are disposed between the piston and the inner shaft. Inner ball bearings travel in the straight grooves and rotate the inner shaft as the piston rotates. The ball screw rotary actuator also includes an outer ball cage to position the outer ball bearings in a spaced configuration, an outer indexing gear to control a position of the outer ball cage, an inner ball cage to position the inner ball bearings in a spaced configuration, and an inner indexing gear to control a position of the inner ball cage.

Abstract: Ball screw rotary actuator with ball cage. In one embodiment, a ball screw rotary actuator includes an outer cylinder, a piston, and inner shaft. Outer ball bearings travel in helical groove between the outer cylinder and position to rotate the piston as it translates due to fluid pressure. The inner shaft is situated radially inward of the piston, and straight grooves are disposed between the piston and the inner shaft. Inner ball bearings travel in the straight grooves and rotate the inner shaft as the piston rotates. The ball screw rotary actuator also includes an outer ball cage to position the outer ball bearings in a spaced configuration, an outer indexing gear to control a position of the outer ball cage, an inner ball cage to position the inner ball bearings in a spaced configuration, and an inner indexing gear to control a position of the inner ball cage.

Abstract: Ball screw rotary actuator with independent ball paths. In one embodiment, a ball screw rotary actuator includes an outer cylinder including a fluid port, a piston configured to translate within the outer cylinder due to fluid pressure, helical grooves disposed between the outer cylinder and the piston, and outer ball bearings configured to travel in the helical grooves to rotate the piston within the outer cylinder as the piston translates. The ball screw rotary actuator also includes an inner shaft situated radially inward of the piston, straight grooves disposed between the piston and the inner shaft, and inner ball bearings configured to travel in the straight grooves, and to rotate the inner shaft as the piston rotates.

Abstract: An aircraft landing gear structure includes a strut assembly and a wheel assembly operatively coupled to the strut assembly. The strut assembly includes an upper tubular housing and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing such that the overall length of the strut assembly is transitioned between an extended configuration and a retracted configuration for stowage during flight. The wheel assembly includes a forward link pivotally coupled to the upper tubular housing and a truck beam that is pivotally coupled to the lower tubular housing such that translation of the lower tubular housing with respect to the upper tubular housing causes pivoting of the forward link and the truck beam with respect to one another, thereby tilting and/or raising a wheel of the wheel assembly with respect to the upper tubular housing.

Abstract: An additive manufacturing system includes a foil supply drum, a melting energy source, and a processor. The foil supply drum is configured to be rotated for dispensing a foil sheet over a substrate surface supported by a build element. The melting energy source is configured to direct at least one melting energy beam onto a non-melted region of the foil sheet located over the substrate surface. The processor is configured to execute computable readable program instructions based on a three-dimensional digital definition of the object, and control the melting energy beam to selectively melt at least some of the non-melted region into melted portions forming a material layer of the object onto the substrate surface while separating the melted portions from non-melted portions, and command rotation of the foil supply drum for dispensing the foil sheet during manufacturing of the object in correspondence with the digital definition.

Abstract: An aircraft landing gear structure includes a retract actuator and a shrink mechanism. The retract actuator is configured to transition a strut assembly of the aircraft landing gear structure between an extended configuration and a retracted configuration via the shrink mechanism, thereby reducing the overall longitudinal length of the strut assembly. The retract actuator is also configured to retract the aircraft landing gear into a stowage area of the aircraft during flight, via a retraction mechanism. The retraction mechanism may be a walking beam that rotates about a retraction axis to retract the aircraft landing gear structure, while simultaneously actuating the shrink mechanism, such as via a drive link coupling the retraction mechanism and the shrink mechanism. The shrink mechanism may be mechanically slaved to the retraction mechanism. The shrink mechanism may be a locking link assembly.

Abstract: An aircraft landing gear structure according to the present disclosure includes a strut assembly and a wheel assembly operatively coupled to the strut assembly. The strut assembly includes an upper tubular housing and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing such that the overall length of the strut assembly is transitioned between an extended configuration and a retracted configuration for stowage during flight. The wheel assembly includes a forward link pivotally coupled to the upper tubular housing and a truck beam that is pivotally coupled to the lower tubular housing such that translation of the lower tubular housing with respect to the upper tubular housing causes pivoting of the forward link and the truck beam with respect to one another, thereby tilting and/or raising a wheel of the wheel assembly with respect to the upper tubular housing.

Abstract: A strut assembly for an aircraft landing gear structure is transitioned between an extended configuration, corresponding to the aircraft being off the ground, and a retracted configuration, in which the strut assembly is shortened along its longitudinal axis with respect to the extended configuration, for stowage during flight. The strut assembly includes an upper bulkhead supported by an upper tubular housing, and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing. To transition the strut assembly to the retracted configuration, translation of the upper bulkhead with respect to the upper tubular housing mechanically causes translation of the lower tubular housing to a retracted position, such that the overall length of the strut assembly is reduced. The strut assembly may be an oleo strut assembly.

Abstract: An aircraft landing gear structure includes a strut assembly and a wheel assembly operatively coupled to the strut assembly. The strut assembly includes an upper tubular housing and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing such that the overall length of the strut assembly is transitioned between an extended configuration and a retracted configuration for stowage during flight. The wheel assembly includes a forward link pivotally coupled to the upper tubular housing and a truck beam that is pivotally coupled to the lower tubular housing such that translation of the lower tubular housing with respect to the upper tubular housing causes pivoting of the forward link and the truck beam with respect to one another, thereby tilting and/or raising a wheel of the wheel assembly with respect to the upper tubular housing.

Abstract: An additive manufacturing system includes a foil supply drum, a melting energy source, and a processor. The foil supply drum is configured to be rotated for dispensing a foil sheet over a substrate surface supported by a build element. The melting energy source is configured to direct at least one melting energy beam onto a non-melted region of the foil sheet located over the substrate surface. The processor is configured to execute computable readable program instructions based on a three-dimensional digital definition of the object, and control the melting energy beam to selectively melt at least some of the non-melted region into melted portions forming a material layer of the object onto the substrate surface while separating the melted portions from non-melted portions, and command rotation of the foil supply drum for dispensing the foil sheet during manufacturing of the object in correspondence with the digital definition.

Abstract: An aircraft landing gear structure according to the present disclosure includes a strut assembly and a wheel assembly operatively coupled to the strut assembly. The strut assembly includes an upper tubular housing and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing such that the overall length of the strut assembly is transitioned between an extended configuration and a retracted configuration for stowage during flight. The wheel assembly includes a forward link pivotally coupled to the upper tubular housing and a truck beam that is pivotally coupled to the lower tubular housing such that translation of the lower tubular housing with respect to the upper tubular housing causes pivoting of the forward link and the truck beam with respect to one another, thereby tilting and/or raising a wheel of the wheel assembly with respect to the upper tubular housing.

Abstract: An aircraft landing gear structure according to the present disclosure includes a retract actuator and a shrink mechanism. The retract actuator is configured to transition a strut assembly of the aircraft landing gear structure between an extended configuration and a retracted configuration via the shrink mechanism, thereby reducing the overall longitudinal length of the strut assembly. The retract actuator is also configured to retract the aircraft landing gear into a stowage area of the aircraft during flight, via a retraction mechanism. In some examples, the retraction mechanism is a walking beam that rotates about a retraction axis to retract the aircraft landing gear structure, while simultaneously actuating the shrink mechanism, such as via a drive link coupling the retraction mechanism and the shrink mechanism. In some examples, the shrink mechanism is mechanically slaved to the retraction mechanism. The shrink mechanism is a locking link assembly in some examples.

Abstract: A strut assembly for an aircraft landing gear structure according to the present disclosure is transitioned between an extended configuration, corresponding to the aircraft being off the ground, and a retracted configuration, in which the strut assembly is shortened along its longitudinal axis with respect to the extended configuration, for stowage during flight. The strut assembly includes an upper bulkhead supported by an upper tubular housing, and a lower tubular housing configured to be longitudinally translated with respect to the upper tubular housing. To transition the strut assembly to the retracted configuration, translation of the upper bulkhead with respect to the upper tubular housing mechanically causes translation of the lower tubular housing to a retracted position, such that the overall length of the strut assembly is reduced. In some examples, the strut assembly is an oleo strut assembly.

Abstract: A hydraulic strut assembly, for use in a semi-levered landing gear in an aircraft, comprising an actuator and a manifold associated with the actuator. The actuator comprises a housing, a first piston, a second piston, and a third piston. The first piston is positioned between outer and inner cylindrical structures of the housing. The outer and inner cylindrical structures and first piston form an outer chamber that receives a first fluid. The inner cylindrical structure, the first piston, and the second piston, which is nested within the first piston, form an inner chamber, which holds a second fluid comprising a gas. A volume of the inner chamber changes when at least one of the first and second pistons moves. The third piston is positioned between the outer cylindrical structure and the first piston. The first, second, and third pistons move in a direction parallel to an axis through the housing.

Abstract: A method and apparatus for air-ground detection. A truck beam of a semi-levered landing gear is mounted on a pivot pin. The truck beam is configured to rotate about the pivot pin between a toes down position and a toes up position. A positioning mechanism is connected to a locking mechanism that secures an angle of the truck beam in the toes up position. The locking mechanism is secured in a steady state and configured to change from the steady state to a locked state in response to an initial ground contact. A sensor is connected to the locking mechanism. The sensor is configured to detect a change from the steady state to the locked state.

Abstract: A device including a first hydraulic piston, a second hydraulic piston disposed within the first hydraulic piston, and a third hydraulic piston disposed within both the first hydraulic piston and the second hydraulic piston. The first, second, and third hydraulic pistons are contained within a common outer wall. A manifold is connected to the first, second, and third hydraulic pistons. The manifold is disposed relative to the first, second, and third hydraulic pistons such that a fluid moving in the manifold can control positions of the first, second, and third hydraulic pistons.

Abstract: A hydraulic strut assembly, for use in a semi-levered landing gear in an aircraft, comprising an actuator and a manifold associated with the actuator. The actuator comprises a housing, a first piston, a second piston, and a third piston. The first piston is positioned between outer and inner cylindrical structures of the housing. The outer and inner cylindrical structures and first piston form an outer chamber that receives a first fluid. The inner cylindrical structure, the first piston, and the second piston, which is nested within the first piston, form an inner chamber, which holds a second fluid comprising a gas. A volume of the inner chamber changes when at least one of the first and second pistons moves. The third piston is positioned between the outer cylindrical structure and the first piston. The first, second, and third pistons move in a direction parallel to an axis through the housing.

Abstract: A method and apparatus for air-ground detection. A truck beam of a semi-levered landing gear is mounted on a pivot pin. The truck beam is configured to rotate about the pivot pin between a toes down position and a toes up position. A positioning mechanism is connected to a locking mechanism that secures an angle of the truck beam in the toes up position. The locking mechanism is secured in a steady state and configured to change from the steady state to a locked state in response to an initial ground contact. A sensor is connected to the locking mechanism. The sensor is configured to detect a change from the steady state to the locked state.

Abstract: A method and apparatus for air-ground detection. A truck beam of a semi-levered landing gear is mounted on a pivot pin. The truck beam is configured to rotate about the pivot pin between a toes down position and a toes up position. A positioning mechanism is connected to a semi-levered linkage assembly that secures an angle of the truck beam in the toes up position. The semi-levered linkage assembly is secured in a steady state and configured to change from the steady state to a locked state in response to an initial ground contact. A sensor is connected to the semi-levered linkage assembly. The sensor is configured to detect a change from the steady state to the locked state.

Abstract: A hydraulic strut assembly, for use in a semi-levered landing gear in an aircraft, comprising an actuator and a manifold associated with the actuator. The actuator comprises a housing, a first piston, a second piston, and a third piston. The first piston is positioned between outer and inner cylindrical structures of the housing. The outer and inner cylindrical structures and first piston form an outer chamber that receives a first fluid. The inner cylindrical structure, the first piston, and the second piston, which is nested within the first piston, form an inner chamber, which holds a second fluid comprising a gas. A volume of the inner chamber changes when at least one of the first and second pistons moves. The third piston is positioned between the outer cylindrical structure and the first piston. The first, second, and third pistons move in a direction parallel to an axis through the housing.