Device for visually indicating a pressure or temperature condition
Patent 4793717 Issued on December 27, 1988. Estimated Expiration Date: 
December 27, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 27, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3465590 3597976 3615719 3665770 3922917 Selected time interval indicating device Reservoir pad for time indicator Patent #: 3962920 InventorApplicationNo. 06/375376 filed on 05/06/1982US Classes:374/160, Melting or softening116/219With absorbing or diffusing materialExaminersPrimary: Cuchlinski, William A. Jr.Assistant: Scanlon, Patrick R. Attorney, Agent or FirmInternational ClassesG01L 19/00 (20060101)G01L 19/12 (20060101) G01K 11/06 (20060101) G01K 3/00 (20060101) G01K 11/00 (20060101) AbstractIndicating device suitable for visibly indicating conditions such as the application of force or pressure or the exposure to a critical temperature. The device includes a porous pad containing an indicating dyed chemical, a wick maintained in spaced relation to the pad and a snap action activating means. The activating means forces the wick into contact with the pad and dyed chemical migration provides visible indication of the application of force or pressure. The indicating dyed chemical may be frozen and the activating means engaged. Upon reaching a critical temperature the frozen chemical melts allowing dye migration into the wick and a visible indication of exposure to the critical temperature. | |
