Nitinol washers
First Claim
1. A method of making a Nitinol washer, comprising:
- selecting a sheet or plate of monolithic hot-worked Nitinol; and
cutting an annular body with a central opening from said sheet.
1 Assignment
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Accused Products
Abstract
A lock washer for locking a threaded fastener from loosening under vibration includes an annular body with a central opening cutting from a sheet or plate of Nitinol, and an integral layer of NiTiOx on at least one face of said body. The lock washer is made of a high transition temperature form of Type 55 Nitinol that remains in its martensitic state in all normal conditions of use. The martensitic Nitinol initially yields during torquing of the nut to allow the nut to indent itself slightly into the lock washer. The resulting cold working of the washer material causes a transformation into stress-induced martensite, which is strong and elastic to resist further deformation and also exerts a preload on the bolt shank. The nut, indented into the lock washer, strongly resists turning under vibration, which effect is further enhanced by the vibration absorbing characteristics of the material. The integral layer of NiTiOx on the surface of the washer provides electrical insulation, minimizing galvanic corrosion.
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Citations
18 Claims
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1. A method of making a Nitinol washer, comprising:
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selecting a sheet or plate of monolithic hot-worked Nitinol; and
cutting an annular body with a central opening from said sheet. - View Dependent Claims (2, 3, 4)
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5. A fastened assembly, comprising:
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two juxtaposed parts having an aligned fastener hole therethrough;
a fastener under tension extending through said aligned hole in said two parts, said fastener having a shank extending through said hole and a securement device, such as a nut or a swaged collar, for maintaining a tensile preload on said shank;
an annular Nitinol washer between a protected item and an impacting force;
whereby said impacting force will deform said Nitinol structure and said Nitinol structure will absorb significant portions of the energy in said impacting force by deforming said Nitinol washer. - View Dependent Claims (6, 7, 8, 9)
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10. An article, comprising:
an annular disc having a central opening, said annular disc being made of monolithic Nitinol. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
Specification