Timing device

• US 7,434,535 B2
• Filed: 12/31/2003
• Issued: 10/14/2008
• Est. Priority Date: 12/31/2003
• Status: Expired due to Fees

• Current Assignee: Church & Dwight Company Incorporated
• Original Assignee: Church & Dwight Company Incorporated
• Inventors: Adamy, Steven T.
• Primary Examiner(s): Smith; R. A.
• Assistant Examiner(s): Johnson; Amy Cohen
• Application Number:
  US10/749,685
• Publication Number:
  US 20050141348A1
• Time in Patent Office: 1,749 Days
• Field of Search: 116/206, 116216-219, 374/161, 374/162, 374/106, 368/114, 368/327
• US Class Current: 116/206
• CPC Class Codes: G01K 3/04 in respect of time
• CPC Class Codes: G04F 1/06 by flowing-away of a prefixed quantity of fine-granular or liquid materials, e.g. sand-glass, water-clock

Abstract

A timing device for visually determining the passage of a preselected period of time including a redox indicator and a metal salt wherein the indicator undergoes an observable change in color which is related to the desired preselected period of time.

Claims

1. A timing device for visually determining the passage of a preselected period of time comprising:

a redox couple containing a redox indicator in combination with a reactable metal ion, said redox couple deposed within a matrix, said matrix being exposable to air such that over a period of time during exposure to air, the redox indicator changes color and thereby indicates the passage of a predetermined period of time.

2. The timing device of claim 1 wherein the matrix is a film-forming polymer.

3. The timing device of claim 2 wherein the film-forming polymer is a cellulose derivative.

4. The timing device of claim 2 wherein said matrix has a thickness based on a wet film of said polymer of from 5 to 50 mil.

5. The timing device of claim 1 wherein the matrix is attached to an adhesive tape and is adhered to a package containing a consumer product.

6. The timing device of claim 1, wherein the redox indicator is selected from the group consisting of indigo carmine and methylene blue.

7. The timing device of claim 1, wherein the metal ion is Sn²⁺.

8. A method for determining when a consumer product has reached an end to its useful shelflife comprising:

preparing a timing device comprising a redox couple containing a redox indicator and a reactable metal ion, said redox couple deposed within a matrix, said matrix being exposable to air;

attaching the timing device to an outside surface of the consumer product;

observing the timing device for color changes, which color changes coincide with the end of the useful shelflife of the said consumer product.