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US 8,617,325 B2Granted
Actively damped tension member
AssigneeThyssenkrupp Elevator AG
InventorsRory S. Smith, Stefan Kaczmarczyk
Life of this patent
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Abstract
A system and method for actively damping tension members modulates the natural frequency of shape memory alloys incorporated into tension members, such as suspension ropes or cables. The frequency of the tension member can be modulated by heating the shape memory alloy, such modulation preventing potentially destructive resonance with natural exciting forces.
Claims21
A tension member for use with an elevator car, the tension member comprising:
- (a) a first region, wherein at least a portion of the first region comprises a shape memory alloy configured to exhibit a phase change, wherein the phase change provides a change in the stiffness of the first region;
- (b) a second region, wherein at least a portion of the second region comprises load bearing material, wherein the load bearing material is configured to support the weight of the elevator;
- (c) an elongated body having first and second ends, wherein the load bearing material of the second region and the shape memory alloy of the first region are positioned along the elongated body of the tension member, wherein the tension member is configured to suspend the elevator car from a select one of the first and second ends;
- and
- (d) a core, wherein the shape memory alloy is retained with the core.
2 more elements
A tension member for use with an elevator car, the tension member comprising:
- (a) a first region, wherein at least a portion of the first region, comprises a shape memory alloy configured to exhibit a phase change, wherein the phase change provides a change in the stiffness of the first region;
- (b) a second region, wherein at least a portion of the second region comprises load bearing material, wherein the load bearing material is configured to support the weight of the elevator;
- (c) an elongated body having first and second ends, wherein the load bearing material of the second region and the shape memory alloy of the first region are positioned along the elongated body of the tension member, wherein the tension member is configured to suspend the elevator car from a select one of the first and second ends;
- and
- (d) a core, wherein the shape memory alloy is retained outside of the core.
2 more elements
A method for actively damping a tension member comprising the steps of:
- (a) suspending an elevator car using a tension member, wherein the tension member comprises at least a portion of shape memory alloy configured to exhibit a phase change, wherein the at least a portion of shape memory alloy is retained within a core of the tension member, wherein the core of the tension member is at least partially surrounded by aramid fibers;
- (b) inducing a phase change in the shape memory alloy;
- (c) modulating the phase change of the shape memory alloy to alter the natural frequency of the tension member;
- (d) calculating the frequency of exciting forces;
- (e) calculating the natural frequency of the tension member;
- and
- (f) controlling modulation of the phase change of the shape memory alloy such that the frequency of the exciting forces does not substantially match the natural frequency of the tension member.
4 more elements
Dependencies are inferred from the claim text.