This paper aims to enhance the practical applicability of relational grammars, which have been devised for the semantic analysis of natural language. We focus on their application in knowledge representation. In particular, we address how the representation problem for KL-ONE-based knowledge representation systems can be automatically solved with the help of relational grammars. New rules are presented for natural language formulations, like has sons and has at least two sons, commonly arising in application domains. For accommodating the latter kind of sentences we introduce a new class of so-called (concrete) graded Peirce algebras. A graded Peirce algebra is a Peirce algebra endowed with a countable set of numerical quantifier operations.