US3696679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thaw sensor
Assignee: Individual
•
Filing: 1970-12-30
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Granted: 1972-10-10
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Expires: 1990-12-30
Abstract
Abstract An improved method and device for determining if a frozen article has been thawed or has exceeded a predetermined temperature during storage or transit. A resilient electrical conductor shaped in the general form of a loop is frozen in a mass of material such that the loop is stressed. The frozen mass and conductor are stored with the frozen article. When the mass of material is thawed, the stressed loop relaxes to change electrical states either from an open circuit to a shorted circuit or from a shorted circuit to an open circuit. The changed state is maintained, even though the article may be refrozen. A shorted turn tester is used to determine the electrical state of the loop, thereby indicating if the frozen article has been thawed.
Inventors
- 👤 Victor S Peterson
- 👤 Arthur J Gnecco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:48
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
96 words
A device for use with means for measuring electrical properties of a coil to determine if an article has exceeded a predetermined temperature comprising, in combination, a mass of frozen material having a melting point at the predetermined temperature, a resilient electrical conductor having ends formed into a normally open loop, said loop being stressed by said mass of material, and means electrically shorting said loop ends when said loop is stressed by said frozen material, said loop ends becoming electrically open through the resiliency of said conductor when said mass of frozen material is thawed.
Claim 2
Independent Claim
96 words
A device for use with means for measuring electrical properties of a coil to determine if an article has exceeded a predetermined temperature comprising, in combination, a mass of frozen material having a melting point at the predetermined temperature, a resilient electrical conductor having ends formed into a normally open loop, said loop being stressed by said mass of material, and means electrically shorting said loop ends when said loop is stressed by said frozen material, said loop ends becoming electrically open through the resiliency of said conductor when said mass of frozen material is thawed.
Claim 3
Dependent Claim
26 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 1, wherein said material comprises a sponge saturated with water.
Claim 4
Dependent Claim
22 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 1, wherein said material is water.
Claim 5
Dependent Claim
36 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 1, wherein said material comprises a mixture of water and an impurity to give the material the predetermined melting temperature.
Claim 6
Independent Claim
98 words
A device for use with means for measuring electrical properties of a coil to determine if an article has exceeded a predetermined temperature comprising, in combination, a mass of frozen material having a melting point at the predetermined temperature, a resilient electrical conductor having ends formed into a normally electrically shorted loop, said loop being stressed by said mass of material, and means maintaining said loop ends electrically separated when said loop is stressed by said frozen material, said loop ends becoming electrically shorted through the resiliency of said conductor when said mass of frozen material is thawed.
Claim 7
Independent Claim
98 words
A device for use with means for measuring electrical properties of a coil to determine if an article has exceeded a predetermined temperature comprising, in combination, a mass of frozen material having a melting point at the predetermined temperature, a resilient electrical conductor having ends formed into a normally electrically shorted loop, said loop being stressed by said mass of material, and means maintaining said loop ends electrically separated when said loop is stressed by said frozen material, said loop ends becoming electrically shorted through the resiliency of said conductor when said mass of frozen material is thawed.
Claim 8
Dependent Claim
26 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 5, wherein said material comprises a sponge saturated with water.
Claim 9
Dependent Claim
22 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 5, wherein said material is water.
Claim 10
Dependent Claim
36 words
A device for determining if an article has exceeded a predetermined temperature, as defined in claim 5, wherein said material comprises a mixture of water and an impurity to give the material the predetermined melting temperature.
Claim 11
Independent Claim
132 words
A method for determining if an article has been heated above a predetermined temperature during storage comprising the steps of: forming a loop of electrically conductive resilient material such that said loop has ends which may be deformed between first and second stressed states, the resiliency of said loop urging said loop ends to said first state wherein said loop ends are electrically shorted together, said loop ends being electrically an open circuit when in said second state; stressing said loop to said second stressed state with a mass of frozen material having a melting point at the predetermined temperature; storing said frozen material and said loop with the article; and measuring if said loop is in said first stressed state or said second stressed state by means of an electromagnetic field.
Claim 12
Independent Claim
132 words
A method for determining if an article has been heated above a predetermined temperature during storage comprising the steps of: forming a loop of electrically conductive resilient material such that said loop has ends which may be deformed between first and second stressed states, the resiliency of said loop urging said loop ends to said first state wherein said loop ends are electrically shorted together, said loop ends being electrically an open circuit when in said second state; stressing said loop to said second stressed state with a mass of frozen material having a melting point at the predetermined temperature; storing said frozen material and said loop with the article; and measuring if said loop is in said first stressed state or said second stressed state by means of an electromagnetic field.
Claim 13
Independent Claim
132 words
A method for determining if an article has been heated above a predetermined temperature during storage comprising the steps of: forming a loop of electrically conductive resilient material such that said loop has ends which may be deformed between first and second stressed states, the resiliency of said loop urging said loop ends to said first state wherein said loop ends are electrically an open circuit, said loop ends being electrically shorted together when in said second state; stressing said loop to said second stressed state with a mass of frozen material having a melting point at the predetermined temperature; storing said frozen material and said loop with the article; and measuring if said loop is in said first stressed state or said second stressed state by means of an electromagnetic field.
Claim 14
Independent Claim
132 words
A method for determining if an article has been heated above a predetermined temperature during storage comprising the steps of: forming a loop of electrically conductive resilient material such that said loop has ends which may be deformed between first and second stressed states, the resiliency of said loop urging said loop ends to said first state wherein said loop ends are electrically an open circuit, said loop ends being electrically shorted together when in said second state; stressing said loop to said second stressed state with a mass of frozen material having a melting point at the predetermined temperature; storing said frozen material and said loop with the article; and measuring if said loop is in said first stressed state or said second stressed state by means of an electromagnetic field.
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |