Active material elements having reinforced structural connectors
AssigneeGM Global Technology Operations LLC
InventorsKenneth A. Strom, Nancy L. Johnson, Nilesh D. Mankame
Life of this patent
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Abstract
A load-carrying active material assembly and a method of preparing such an active material assembly suitable for attachment to a movable component of a mechanism is described. The assembly includes a shape memory alloy (SMA) element, a connector adapted to engage the moveable component mechanically crimped to the SMA element, and a filler material disposed intermediate the connector and SMA element. The filler may be a solder or a polymer. Methods for appropriately distributing the filler material and for promoting good adhesion of the filler to the SMA element and the connector are described.
Claims20
A mechanism having a movable component, operable by an attached, elongated, linear shape memory alloy element with an end and secured to the mechanism through an electrically-conductive unitary, load-transmitting connector, the shape memory alloy element being adapted and arranged to repeatedly cycle the mechanism between a first configuration and a second configuration while under tensile load, the mechanism comprising:
- the moveable component connected, through the electrically-conductive unitary load-transmitting connector, to the end of the elongated linear SMA element, the SMA element having a surface, the connector having a first portion with a feature adapted to engage a complementary feature on the component and a second, element-retaining portion;
- the element-retaining portion initially comprising an elongated, deformable casing with opposing openings sized to receive the end of the SMA element, the end of the SMA element extending from end to end of the element-retaining portion, the casing then being compacted to contact and compressively engage a portion of the surface of the SMA element, the compacted casing further comprising a space-filling filler material engaging the compressed casing and the SMA element surface, the filler and the casing-engaged SMA element surface cooperating to restrain relative motion between the connector and the SMA element during operation of the mechanism.
A method of connecting a linear shape memory alloy (SMA) element to a component of a mechanism where the shape memory alloy element repeatedly applies tensile forces to the component to operate the mechanism, the method comprising:
- forming, on the component, an engageable attachment feature;
- selecting a connector with an attachment feature complementary to the engageable attachment feature on the component and a retaining feature for joining the elongated linear SMA element to the connector, the retaining feature comprising a deformable elongated metal casing with opposing openings, the casing having an inner wall defining a receptacle with a length, the receptacle being sized and adapted to receive the SMA element;
- inserting an end of the SMA element through one of the openings and into the receptacle in a manner which does not prejudice the function of the attachment feature, the length of the inserted end being at least equal to the length of the receptacle, the length of the receptacle being selected to enable a suitably strong joint between the SMA element and the retaining feature of the connector to restrain relative motion between the connector and the SMA element during repeated operation of the mechanism;
- crimping the metal casing to bring a portion of the casing into compressive engagement with a surface of the inserted length of SMA element;
- inserting a filler into the receptacle shell to engage the casing and the SMA element;
- and
- attaching the connector to the component.
Dependencies are inferred from the claim text.