Patent ID: 7468013

Claim:
A two-arm belt tensioner ( 16 ) for a belt drive ( 1 ) of an internal combustion engine ( 3 ); the belt tensioner ( 16 ) comprising a tubular supporting portion ( 20 ) fixed to a fixed supporting structure ( 6 ); a first ( 24 ) and a second ( 23 ) arm fitted to said tubular supporting portion ( 20 ) to rotate about a common hinge axis ( 21 ); a first ( 25 ) and a second ( 26 ) idle wheel fitted to respective ends ( 28 ) of said first ( 24 ) and said second ( 23 ) arm and cooperating with respective branches ( 12 )( 13 ) of a belt ( 11 ) of said drive; and elastic forcing means ( 33 ) for forcing said first ( 24 ) and said second ( 23 ) arm towards each other to keep said wheels ( 25 )( 26 ) in contact with said respective branches ( 12 )( 13 ) of the belt ( 11 ); characterized in that said elastic forcing means ( 33 ) comprise a torsionally elastic elongated member ( 34 ) extending through said tubular supporting portion ( 20 ), coaxially with the hinge axis ( 21 ), and having respective opposite end portions ( 37 )( 38 ) projecting outwards of said tubular supporting portion ( 20 ); a first ( 40 ) and a second ( 41 ) end cap located at opposite axial ends of said tubular supporting portion ( 20 ), and each fitted in angularly fixed manner to a respective said end portion ( 37 )( 38 ); said second cap ( 41 ) being fitted directly with one end ( 31 ) of said second arm ( 23 ), and defining a radial opening ( 46 ) fitted through with said first arm ( 24 ); angular connecting means ( 43 ; 51 ) being interposed between said first arm ( 24 ) and said first cap ( 40 ), and housed inside said tubular supporting portion ( 20 ) and said first and said second cap ( 40 )( 41 ).