Actuator device with intermediate rollers

An actuator device, comprising:

• a support;
• a longitudinal drive rod having a rear end section mounted and rotating inside said support, said drive rod having an external screw thread;
• a rotation drive for rotational driving of said drive rod, the rotation drive supported by said support 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, the sheath 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 each 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, said front end section carrying said external screw thread of the drive rod and said gear teeth of the drive rod;
• 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,
• wherein, when the drive rod is driven in rotation by the rotation drive 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.

An actuator device, comprising:

• a support;
• a motor carried by the support and having a shaft;
• a longitudinal drive rod having a rear end section spaced apart from a front end section, said drive rod having an external screw thread;
• the rear end section directly mounted and rotating inside said support and coupled to the shaft of the motor;
• a longitudinal sheath positioned around and coaxially to said drive rod, the sheath having a long 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 front end section of said drive rod having gear teeth coupled together;
• said front end section carrying said external screw thread of the drive rod and said gear teeth of the drive rod;
• 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 the rollers roll around the drive rod by effect of the gear teeth and without longitudinal movement with respect to the drive rod;
• the helix angle of the screw thread of said rollers being different from the helix angle of said screw thread of said sheath, and the rotation movement of the drive rod is transformed into a longitudinal movement of the sheath retained in rotation,
• wherein, when the drive rod is driven in rotation by the rotation drive and the sheath is retained in rotation, the rotation movement thereof is transformed into a longitudinal movement of the sheath by the rollers rotating around themselves and rolling with respect to the drive rod and the sheath, without longitudinal movement of the rollers with respect to the drive rod.