Patent ID: 8353795

Claim:
A tensioner for a belt of a drive of a motor vehicle, comprising: a first and a second idle pulleys designed to co-operate with respective belt runs of said belt; a first arm bearing said first idle pulley, said first arm being hinged about a mobile axis; a second arm hinged to said first arm about the mobile axis and bearing said second pulley, said first and second arms being rotatable relative to each other about the mobile axis; elastic means secured to a mobile element, the elastic means acting directly on one of said first and second arms and indirectly on the other of said first and second arms for tensioning said belt; the mobile element being distinct from said first and second arm and mobile during operation, said mobile axis being substantially perpendicular to and carried by said mobile element, said mobile element changing positions in reaction to changes in tensioning action on the belt runs, said positions being determined by an equilibrium caused by said changes in tensioning action; and arrest elements on said mobile element, said arrest elements co-operating with said arms for limiting opening of said arms with respect to one another.