Limitations in the body of the claim that rely upon and derive antecedent basis from the preamble may render the preamble a necessary component of the claimed invention. A claim drafter should therefore take care to avoid, as here, converting the entire preamble into a limitation when one structure recited in the preamble is deemed a limitation by virtue of providing antecedent basis for a later reference.
Background / Facts: The patents being asserted here are directed to cutter bits, bit holders, and bit blocks used in road milling, mining, and trenching operations. The patents purport to provide a better means for allowing the removal of a bit from a bit holder or a bit block, especially when the bit becomes worn and in need of replacement. In this regard, the claims are directed to “[a] bit holder for use in road milling, trenching and mining equipment as part of an assembly including a bit, said bit holder and a bit block,” where the “bit” is “mountable in a first bore through said bit holder and said bit holder being mountable in a second bore through said bit block,” as stated in the preamble. The body of the claims then recites “a bit receiving front portion” and “a shank portion.”
Issue(s): Whether a “bit” is a required structural element of the asserted claims even though it is recited in the preamble.
Holding(s): Yes. “[T]he preambles of the asserted claims recite essential elements of the invention pertaining to, among other things, the bit, the bit holder, and the bit block in addition to the mounting relationship among these elements that make up the claimed bit assembly.” The body of the claims “does not recite the complete invention, but refers back to the features of the bit assembly stated in the preamble, so that these references in the body of the claim derive their antecedent bases from the preamble.”