Presence detector
US5417487A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 25, 1993 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Oct 25, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V8/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A presence detector for detecting the presence of a heat source, including a motion detector having a predetermined field of view. The motion detector is activated by movement of a heat source a certain minimum amount within that predetermined field of view. An actuator is provided for moving the motion detector sufficient to change the position of the field of view by at least that minimum amount. The actuator includes a shape memory alloy wire. The motion detector is movably or rotatably mounted to a support. The actuator is connected at one end to the motion detector and at the other to the support. The actuator also includes a biasing or return spring for re-stretching the shape memory alloy wire back to its original length once it has contracted. A strain relief spring is also provided, having a spring rate substantially higher than that of the return spring, for relieving strain on the shape memory alloy wire in case the detector rotatable mounting seizes or otherwise is prevented from moving freely.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.