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US 4,047,339 AGranted
High load extendible structure
AssigneeFairchild Industries, Inc.
InventorsGordon A. Smith, James M. Talcott
Life of this patent
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AssigneeFairchild Industries, Inc.
InventorsGordon A. Smith, James M. Talcott
Estimating the term…
A high load extendible structure including an elongated thin pre-stressed element which has a cross section whose interior portion is curved to form substantially one-half of the perimeter of a circle and whose two exterior portions are each curved in an opposite direction to each form substantially one-quarter of a circle of the same radius as the central portion when the pre-stressed element is unrestrained from a flattened condition. The element is capable of being rolled flat upon a roller and yet can be extended to support or push various loads and plastic beads are located along the edges of the pre-stressed element to provide protection from these sharp edges. An equation is presented for determining the required thickness of the element once the radii associated with the element and the radius of the roller and other parameters for a given application have been determined. A method of forming the elongated thin pre-stressed element is also presented in which the element is formed between a male die having a half circular portion and a female die which has a rectangular channel. Sheets of rubber are utilized in conjunction with the dies to form the element.
A method of forming an elongated thin pre-stressed metallic element comprising placing a flexible non-metallic sheet on a substantially flat metallic sheet which is to be formed into the thin pre-stressed element, and forming at least a portion of the substantially flat metallic sheet by subjecting both the portion of the substantially flat metallic sheet which is to be formed and the adjacently located portion of the flexible non-metallic sheet which is located on the substantially flat metallic sheet to pressure.
A high load extendible apparatus comprising an elongated thin pre-stressed element, said elongated thin element being pre-stressed to have a cross-section whose interior portion is curved to form one-half of the perimeter of a circle with the concave side thereof facing in one direction and whose two exterior portions are each curved to form one quarter of the perimeter of a circle with the concave side thereof facing in another direction and being pre-stressed to have the centers for the radii of all of said circles lie in a common plane when said elongated thin element is unrestrained from a flattened condition.
A high load extendible apparatus comrising a roller, an elongated thin pre-stressed element, said elongated thin element being pre-stressed to have a cross-section whose interior portion is curved to form one-half of the perimeter of a circle with the concave side thereof facing in one direction and whose two exterior portions are each curved to form one quarter of the perimeter of a circle with the concave side thereof facing in another direction and being pre-stressed to have the centers for the radii of all of said circles lie in a common plane when said elongated thin element is unrestrained from a flattened condition, the minimum thickness of said element being determined substantially in accordance with the equation, ##EQU3## where t is the thickness of the element, r is the radius of the roller, S is the applied alternating stress for the desired number of operating cycles for the element, E is Young's modulus, .mu. is Poisson's ratio and R is the radii of the half and quarter circles.
Dependencies are inferred from the claim text.