Safeguard device
First Claim
Patent Images
1. In a safeguard device having a housing including a selective high frequency sensor that triggers an alarm device after receiving high frequency energy, the improvement wherein said housing is provided with a metal sensor which additionally, and independently of said high frequency sensor, controls said alarm device.
0 Assignments
0 Petitions
Accused Products
Abstract
A safeguard device is provided with a high frequency sensor which triggers an alarm device after receiving high frequency energy. To prevent the alarm device being rendered ineffective by high frequency shielding of the safeguard device, a metal sensor is provided in addition which activates the alarm device regardless of the presence of high frequency energy when it is attempted to shield the safeguard device.
12 Citations
17 Claims
- 1. In a safeguard device having a housing including a selective high frequency sensor that triggers an alarm device after receiving high frequency energy, the improvement wherein said housing is provided with a metal sensor which additionally, and independently of said high frequency sensor, controls said alarm device.
-
6. A safeguard device comprising:
a housing;
an alarm device disposed in said housing;
selective high frequency sensor means disposed in said housing for triggering said alarm device after receiving high frequency energy; and
a metal sensor means disposed in said housing for triggering said alarm device, independent of said high frequency sensor means, after detecting the presence of metal adjacent said housing, whereby an attempt to thwart the safeguard device by covering the housing with an electrically conductive high-frequency-effective shielding material, will be detected by said metal sensor means.- View Dependent Claims (7, 8, 9, 10, 11, 12)
-
13. A safeguard device for protecting objects from theft comprising:
-
a housing having means for releasably attaching said housing to an object to be protected; an alarm device disposed in said housing; first sensor means disposed in said housing for triggering said alarm device after receiving high frequency energy of a selected frequency; and a second sensor means disposed in said housing, and operating independently of said first sensor means, for detecting the presence, around said housing, of an undesired metal shield for said high frequency energy, and for triggering said alarm device in response to such detection, whereby an attempt to thwart the safeguard device by covering it with an electrically conductive high frequency effective shielding material will be detected. - View Dependent Claims (14, 15, 16, 17)
-
Specification