Summary of the Invention and Background of the Invention used to Limit Claim Scope

In Boss Control, Inc. v. Bombardier Inc., 410 F.3d 1372, 75 USPQ2d 1038 (Fed Cir. June 8, 2005), Boss Control owns U.S. Patent No. 5,734,206.  U.S. Patent No. 5,734,206 is drawn to a power interrupt apparatus that prevents the unauthorized use of an electrically operated device.  Boss Control sued Bombardier and others for infringement of claim 7, which includes a feature in which “said controller is operative to interrupt power to the load responsive to said code-providing device being operatively disconnected from said controller.”  In order to show infringement, Boss Control wanted a broad interpretation of the term “interrupt” to read on any break off of power or cut off power, which Boss Control asserted was the ordinary meaning of this phrase.  The District Court held that Boss Control was not entitled to this broader interpretation and instead sided with Bombardier in that a narrower (and non-infringing) interpretation was appropriate in view of the use in the patent specification.   On appeal from the judgment of non-infringement, the Federal Circuit held that the term “interrupt” was defined in the specification and is narrower than the broadest possible meaning based upon Summary of the Invention and Background of the Invention sections.

Specifically, the Background of the Invention discussed conventional devices having on/off interrupts, thus indicating that the term “interrupt” was intended to have a narrower meaning that is more than simply a cut off or break off of power.  The Federal Circuit relied upon the following passage to support this interpretation:


In the prior art, means have been provided to prevent unauthorized usage of electrical appliances and similar electrically operated devices, primarily through key operated electro-mechanical circuit interrupt devices. However, such devices conventionally provide for on-off control only, meaning that the device completely interrupts the flow of electrical power to the appliance while in the interrupt or “locked” state, and it connects the appliance to the electrical supply in the operative or “unlocked” state.

Consistent with the Background of the Invention, the Summary of the Invention distinguished the application’s invention over conventional interrupts as being more than a simple on/off function.  The Federal Circuit relied upon the following passage to support this interpretation:

In accordance with one aspect of the invention the appliance or device retains a connection to the power supply while in interrupt or “locked” mode; complete power shutoff only occurs when a preset electrical current is exceeded, thus allowing operation of the appliance’s auxiliary electrical equipment while the interrupt device is in the interrupt mode.

Since the Detailed Description was also consistent with this description in the Summary of the Invention, the Federal Circuit agreed with the District Court and limited the meaning of broad term “interrupt” to only literally cover more than simple on/off functions.


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