US5010320A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self modulating electronic article surveillance marker
Assignee: Pitney Bowes Inc
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Filing: 1989-12-08
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Granted: 1991-04-23
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Expires: 2009-12-08
Abstract
Abstract A marker for an electronic surveillance system includes an element of a magnetostrictive material, and a non-magnetostrictive element of substantially the same size as said magnetostrictive element and firmly affixed thereto.
Inventors
- 👤 Robert A. Cordery
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:23
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2408; G08B13/2411; G08B13/2428; G08B13/2437; G08B13/2442; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
71 words
In an electronic surveillance marker that includes a magnetostrictive first element adapted to experience a dimensional change in a first direction in the presence of a magnetic field, the improvement comprising a second element firmly affixed to said first element, said second element being of a substantially non-magnetostrictive material, whereby said first element bends in the presence of a magnetic field and said bending varies the susceptibility of said first element.
Claim 2
Dependent Claim
71 words
In an electronic surveillance marker that includes a magnetostrictive first element adapted to experience a dimensional change in a first direction in the presence of a magnetic field, the improvement comprising a second element firmly affixed to said first element, said second element being of a substantially non-magnetostrictive material, whereby said first element bends in the presence of a magnetic field and said bending varies the susceptibility of said first element.
Claim 3
Dependent Claim
16 words
The electronic surveillance marker of claim 1 wherein said first and second elements are strip shaped.
Claim 4
Dependent Claim
18 words
The electronic surveillance marker of claim 2 wherein said elements have lengths that are longer than their widths.
Claim 5
Dependent Claim
15 words
The electronic surveillance marker of claim 3 wherein said second element comprises a biasing magnet.
Claim 6
Dependent Claim
17 words
The electronic surveillance marker of claim 3 wherein said second element is glued to said first element.
Claim 7
Dependent Claim
30 words
The electronic surveillance marker of claim 1 wherein said second element is of a material having a speed of sound substantially the same as the material of the first element.
Claim 8
Dependent Claim
16 words
The electronic surveillance marker of claim 1 wherein said first element is of a ferromagnetic material.
Claim 9
Dependent Claim
75 words
An electronic surveillance system comprising a marker, a source of a varying magnetic field, and a detector, said marker being adapted to be positioned in said field and comprising a sandwich of a first layer of a magnetostrictive material and a second layer of a substantially non-magnetostrictive material firmly affixed thereto, whereby said sandwich bends in the presence of a magnetic field, said detector comprising means for detecting signals generated by bending of said sandwich.
Claim 10
Dependent Claim
75 words
An electronic surveillance system comprising a marker, a source of a varying magnetic field, and a detector, said marker being adapted to be positioned in said field and comprising a sandwich of a first layer of a magnetostrictive material and a second layer of a substantially non-magnetostrictive material firmly affixed thereto, whereby said sandwich bends in the presence of a magnetic field, said detector comprising means for detecting signals generated by bending of said sandwich.
Claim 11
Dependent Claim
15 words
The electronic surveillance system of claim 8 wherein said detector comprises an AM radio receiver.
Claim 12
Dependent Claim
19 words
The electronic surveillance system of claim 9 wherein said second layer comprises a magnet for biasing said first layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-22 | 1994-10-22 | 1995-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-22 | 1998-10-22 | 1999-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-22 | 2002-10-22 | 2003-04-23 | $7700.00 | Window Closed / Lapsed |