After Dustin Schlatter won as a freshman in 2006 there was a three year dry spell (2007, 2008, 2009) before Dake came along.
Before that, between Mark Branch in 1994 and Cael Sanderson in 1999 there was a four year dry spell (1995, 1996, 1997, 1998).
The biggest gap, where freshmen were continuously eligible, was between Ed Banach and Matt Reiss in 1980 and Pat Smith in 1990.