Device for detecting metal objects passing through an opening
US5659247A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1995 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Dec 11, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65F2210/1525
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A metal detection device is disclosed and includes a housing defining a central aperture. An induction member is mounted to the housing and surrounds the aperture for generating an output voltage in response to the presence of a metal object near the induction member. A mechanism is provided for calibrating the induction member by comparing the output voltage to a reference voltage to establish a threshold voltage which is unaffected by transient fluctuations in the output voltage. A mechanism is also provided in the housing and spaced about the aperture for selectively sensing an object passing through the aperture. The sensing mechanism generates a detection signal in response to passage of an object through the aperture only upon activation of the sensing mechanism. A mechanism activates the sensing mechanism upon generation of an inductive member output voltage above the threshold voltage. Finally, a device is provided for triggering an alarm in response to the generation of the detection signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.