defined meanings but to include by special definition in this specification structure material or acts beyond the scope of the commonly defined meanings thus if an element can be understood in the context of this specification as including more than one meaning then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself the definitions of the words or elements of the following claims are therefore defined in this specification to include not only the combination of elements which are literally set forth but all equivalent structure material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result in this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements in the claims below or that a single element may be substituted for two or more elements in a claim although elements may be described above as acting in certain combinations and even initially claimed as such it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed.