\makeatletter
\def\@maketitle{%
  \noindent\fbox{%
  	\begin{minipage}{\dimexpr\linewidth-1ex}
  		\begin{center}%
    	{\fontfamily{lmss}\bfseries\selectfont\LARGE \@title \par}%
    	\vskip .5em%
    	{\large \fontfamily{lmss}\selectfont\@author{} -- \@date}
  		\end{center}%
    \end{minipage}}%
}
\makeatother