Elapsed time indicator

• US 4,550,676 A
• Filed: 08/25/1983
• Issued: 11/05/1985
• Est. Priority Date: 08/25/1983
• Status: Expired due to Fees

• Current Assignee: SC Johnson & Son Incorporated
• Original Assignee: SC Johnson & Son Incorporated
• Inventors: Francis, Alan W.
• Primary Examiner(s): Frankfort, Charles
• Assistant Examiner(s): Worth, W. Morris
• Application Number:
  US06/525,928
• Time in Patent Office: 803 Days
• Field of Search: 116/206, 116/207, 116/308, 422/55, 422/56, 422/58, 368/89, 368/327, 252/522 A, 252/962, 252/963, 252/408.1, 374/102, 374/106, 436/2
• US Class Current: 116/206
• CPC Class Codes: G04F 1/02 by consuming prefixed quantities of materials, e.g. by burning candle
• CPC Class Codes: Y10S 252/962 Temperature or thermal history
• CPC Class Codes: Y10S 252/963 Humidity or moisture indicators

Abstract

An elapsed time indicator in which an indicator, such as a flowable colorant, is releasably contained within an enclosure at least a portion of which is a volatilizable, preferably sublimable, substance.

Claims

1. An indicator to signal the passage of a predetermined, approximate time, comprising:

flowable colorant indicator means; and

means enclosing said indicator means, at least a portion of said enclosure means consisting of a substance adapted to volatilize during passage of the predetermined approximate time to release said indicator means from said enclosure means thus providing an indication of the passage of the predetermined approximate time;

said flowable colorant indicator means being intermixed with and held in a sublimable core substance to define a core, said core being disposed within said enclosure means.

2. The indicator of claim 1 wherein said volatilizable substance is sublimable.

3. The indicator of claim 2 wherein said volatilizable substance is selected from a group consisting of para-dichlorobenzene, 2,4,6-triisopropyl-1,3,5-trioxane, camphor, and napthalene.

4. The indicator of claim 1 wherein said flowable colorant indicator means is a powdered dye.

5. The indicator of claim 1 wherein said sublimable core substance is selected from a group consisting of camphor, napthalene, and para-dichlorobenzene.

6. The indicator of claim 5 wherein the volatilizable substance of said enclosure means is selected from a group consisting of para-dichlorobenzene, 2,4,6-triisopropyl-1,3,5-trioxane, camphor, and napthalene.

7. The indicator of claim 2 further including a deposit surface adjacent to said enclosure means to receive said flowable colorant indicator means upon release thereof from said enclosure means.

8. The indicator of claim 7 wherein said deposit surface includes a solvent for said flowable colorant indicator means.

9. The indicator of claim 2 wherein said enclosure means includes a container wall limiting exposure of said sublimable substance and thereby limiting its rate of volatilization.

10. An indicator to signal the passage of a predetermined approximate time, comprising:

indicator means; and

means enclosing said indicator means, at least a portion of said enclosure means being a volatilizable substance whereby after substantially complete volatilization of said substance said indicator means is effective, said enclosure means including a container wall limiting the rate of volatilization of said volatilizable substance, said indicator means including a sublimable core substance to define a core, said core being disposed within said enclosure means.

11. The indicator of claim 10 wherein said indicator means is a flowable colorant.

12. The indicator of claim 11 wherein said flowable colorant is a powdered dye.

13. The indicator of claim 10 wherein said colorant is in a core, intermixed with and held in a sublimable core substance, said core being within said enclosure means.

14. The indicator of claim 13 wherein said volatilizable substance of said enclosure means is selected from a group consisting of para-dichlorobenzene, 2,4,6-triisopropyl-1,3,5-trioxane, camphor, and napthalene.

15. The indicator of claim 14 wherein said sublimable core substance is selected from a group consisting of camphor, napthalene, and para-dichlorobenzene.

16. The indicator of claim 11 further including a deposit surface adjacent to said enclosure means to receive said indicator means upon release thereof from said enclosure means.

17. The indicator of claim 16 wherein said deposit surface includes a solvent for said flowable colorant.