Patent ID: 8051823

Claim:
A combined actuator ( 17 ) comprising: a mobile element ( 19 ); a driver ( 20 ) for displacing the mobile element ( 19 ) along a path ( 21 ); and a rheological control brake ( 23 ), which is mechanically coupled to the mobile element ( 19 ) to adjust the displacement of the mobile element ( 19 ) along the path ( 21 ); wherein the rheological control brake ( 23 ) comprises: at least two contiguous adjustment chambers ( 25 ); a magnetorheological fluid ( 26 ) contained in the two adjustment chambers ( 25 ); at least one sliding piston ( 28 ), which tightly separates the two adjustment chambers ( 25 ) and is mechanically connected to the mobile element ( 19 ); at least one external connection pipe ( 29 ), which reciprocally connects the two adjustment chambers ( 25 ) and is arranged outside the two adjustment chambers ( 25 ); and a driving device ( 30 ) which is coupled to the external connection pipe ( 29 ) so as to apply a variable magnetic field to the magnetorheological fluid ( 26 ) contained in the external connection pipe ( 29 ) for varying the viscosity of the magnetorheological fluid ( 26 ) between a minimum value, at which the rheological fluid ( 26 ) may freely flow through the external connection pipe ( 29 ) and thus allows the sliding of the piston ( 28 ), and a maximum value, at which the magnetorheological fluid ( 26 ) cannot flow through the external connection pipe ( 29 ) and thus prevents the sliding of the piston ( 28 ); wherein the driving device ( 30 ) comprises; a ferromagnetic core ( 31 ), which is open-ring-shaped and has an interruption defining a gap ( 32 ) in which the external connection pipe ( 29 ), is arranged; at least one winding ( 33 ) which is coupled to the ferromagnetic core ( 31 ); and an electric generator ( 34 ) connected to the winding ( 33 ) to make an electric current of adjustable intensity circulate in the winding ( 33 ).