In general, a generic black box diagram will not be sufficient to impart broad corresponding structure to a means-plus-function element. This is especially true if it encompasses all elements capable of performing the recited function (e.g., a box simply labeled with that function). The better approach seems to be to try to walk the line between overly generic black boxes and overly specific design components, by providing examples that incorporate a “general class of known structures,” such as a class of switches in this instance.
Background / Facts: The patent here relates to trim tab systems for use on powerboats. Trim tabs are large plates connected to actuators at the stern of a boat that, when extended into the water, adjust the orientation of the boat for more efficient cruising. In this regard, the claims recite in means-plus-function form a trim tab control system for automatically returning the trim tabs to a fully retracted position (i.e., out of the water) upon removal of power to the boat engine. FIG. 1 of the specification provides a general black box diagram of such a control system, whereas FIG. 2 provides a more specific circuit-level implementation example.
Issue(s): Whether the corresponding structure of the means-plus-function limitation should be limited to the specific circuit shown in FIG. 2, rather than construed broadly as the generic circuit shown in FIG. 1.
Holding(s): Yes. “[The] patent discloses only one specific type of circuit to perform part of the function required by the [means-plus-function] limitation. In such a situation, the corresponding structure should be limited to that specific structure and its equivalents, rather than any circuit capable of performing the required function. … [The] patent does not disclose alternatives to the circuit shown in figure 2, such as, for example, a general class of known switches. Instead, the … patent only discloses one embodiment, that shown in figure 2.”