Failsafe membrane switches: US Pat. No. 7,645,956

U.S. Patent No. 7,645,956, issued on January 12, 2010 to Weber Precision Graphics of Santa Ana, CA, discloses membrane switches that can be interrogated at all times to detect a failure of the switch.

In certain applications (e.g., controls for life support equipment), it’s important that a switch avoid failing at an inappropriate moment.  Failsafe switches can provide continual self-testing to ensure that the switch is operational, or to flag a switch that has failed or may soon fail.    The patent discloses “failsafe” configurations for membrane switches which provide this capability. 

This patent provides a good example of use of a U.S. provisional patent application.  A provisional application is basically a “placeholder” that is filed with the USPTO and can be used to provide a priority date for the information disclosed by the provisional application.  The provisional application itself will never issue as a U.S. patent, however, a regular U.S. patent application filed within one year of the provisional application’s filing date can claim the provisional application’s filing date as its priority date.

For example, when the regular U.S. patent application that resulted in the ’956 patent was originally filed on May 5, 2006, it claimed priority to a U.S. provisional application that was filed on May 16, 2005.  Therefore, when the USPTO considered the patentability of the invention, it looked for references that were prior to the 2005 filing date of the provisional application, rather than the 2006 filing date of the regular application.

Generally, since provisional applications do not have to conform to the formalities required of regular applications, they can be prepared more quickly and less expensively than a regular application.  So in certain circumstances when time is of the essence, provisional applications can provide a way for inventors to quickly get their inventions on file with the USPTO.  However, the provisional application only provides a priority date for the information it contains.  Therefore, care should be used in ensuring that the provisional application includes sufficient information to enable people skilled in the technology to make and use the invention in the best way contemplated by the inventor.  In certain circumstances, relying on a flimsy provisional application with little information in it can give the inventor a false sense of security and can put the patentability of the invention at risk.

According to their website, Weber Precision Graphics has been providing customers with membrane switches and custom sensing solutions for forty years.  This patent is the only one for Weber Precision Graphics on the USPTO assignment database, so it may be the only U.S. patent owned by the company.