Patent ID: 7000495

Claim:
An actuator device, comprising: a support body; a longitudinal drive rod having a rear end section mounted and rotating inside said support body and having an external screw thread; a means for the rotational drive of said drive rod, supported by said support body and having a drive shaft coupled to the rear end of the drive rod; a longitudinal sheath positioned around and coaxially to said drive rod and having an internal screw thread; a series of rollers positioned longitudinally between said drive rod and said sheath and having an external screw thread engaged with the external screw thread of said drive rod and with the internal screw thread of said sheath for producing a relative movement of the sheath with respect to the drive rod; said rollers and said drive rod having gear teeth coupled together; said drive rod having a rear end section mounted and rotating inside said support body; said drive rod having a front end section distant from the rear end section thereof and carrying said external screw thread thereof and said gear teeth thereof; the helix angle of the screw thread of said rollers being equal to the helix angle of said screw thread of said drive rod and being different from the helix angle of said screw thread of said sheath, whereby, when the drive rod is driven in rotation by the rotating drive means and the sheath is retained in rotation, the rotation movement thereof is transformed into a longitudinal movement of the sheath by means of the rollers which rotate around themselves and roll with respect to the drive rod and the sheath, without longitudinal movement of the rollers with respect to the drive rod.