US Patent 7703267 Mower blade coupler with enlarged head and projecting fins

A coupler comprising a shaft, an enlarged head, a proximal end of the shaft, and a journal for contacting and rotating in an annular bearing surface of a component for forming a pin connection with the component. In addition, the coupler includes a plurality of projecting fins projecting from the journal along axes generally parallel to the longitudinal axis of the shaft and are radially spaced around the journal.