Patent ID: 7918758

Claim:
A drive assembly ( 52 ) for driving a rotary member ( 10 ) of a pump ( 7 ) of a combustion engine ( 1 ); the assembly ( 8 ; 52 ) comprising: a movable supporting member ( 15 ); a drive wheel ( 16 ) fitted idly to said movable supporting member ( 15 ); elastic means ( 30 ) exerting a force on said movable supporting member ( 15 ) so that said drive wheel ( 16 ) drivingly contacting said rotary member ( 10 ) and a drive member ( 5 ) powered by said combustion engine ( 1 ) to drive the rotary member ( 10 ); and actuating means ( 81 ) provided to exert a force in opposition to that exerted by said elastic means ( 30 ) to detach said drive wheel ( 16 ) from at least one of said rotary member ( 10 ) and said drive member ( 5 ); said actuating means comprising a reversible electric rotary motor ( 81 ) such that a force exerted by said elastic means ( 30 ) to push said drive wheel ( 16 ) against said rotary member ( 10 ) and said drive member ( 5 ) being greater than the travel resistance of said actuating means ( 81 ) when maintained in a disabled rest condition; said actuating means ( 81 ) also comprising a mechanical drive interposed between an actuator ( 81 ) and said movable supporting member ( 15 ); said movable supporting member ( 15 ) comprising a connecting portion ( 20 ) disposed opposite to an end portion ( 18 ) supporting said drive wheel ( 16 ) and connected to said mechanical drive to move said supporting member ( 15 ) along a circular trajectory; said mechanical drive comprising a gear drive ( 78 ) interposed between said electric rotary motor ( 81 ) and said movable supporting member ( 15 ), and cam actuating means interposed between said gear drive ( 78 ) and said connecting portion ( 20 ); said connecting portion ( 20 ) being a hollow tubular portion having an axis of symmetry ( 23 ) parallel to the axis of rotation ( 19 ) of said drive wheel ( 16 ); said cam actuating means ( 59 ) comprising a first hinge pin ( 60 ) engaging said hollow tubular portion in rotary manner about said axis of symmetry ( 23 ) and hinged to a fixed frame ( 53 ) to rotate about a hinge axis ( 66 ) parallel to and eccentric with respect to the axis of symmetry ( 23 ); said actuating means ( 81 ) rotating said first hinge pin ( 60 ) about said hinge axis ( 66 ); said elastic means comprising a torsion spring ( 30 ) housed in the tubular said connecting portion ( 20 ) and having one end fixed angularly to said first hinge pin ( 60 ) and the opposite end fixed angularly to the tubular said connecting portion ( 20 ); said first hinge pin ( 60 ) being fitted integrally with a radial toothed portion ( 76 ) of said gear drive ( 78 ).