A roller screw system includes a spindle defining a longitudinal axis about which the spindle rotates. A nut at least partially radially surrounds the spindle. The nut is configured for longitudinal motion with respect to the spindle. At least one non-helically grooved roller is interposed radially between the spindle and the nut. A cage maintains the at least one roller in position radially between the spindle and the nut and supports the at least one roller for rotational motion. The nut is moved in longitudinally in a duty cycle responsive to transmission of rotational motion from the spindle to the at least one roller, and transformation of rotational motion of the at least one roller to longitudinal motion of the nut. A home position of the nut and a home position of the cage both move longitudinally after a predetermined number of duty cycles.

A roller screw system includes a spindle defining a longitudinal axis about which the spindle rotates. A nut at least partially radially surrounds the spindle. The nut is configured for longitudinal motion with respect to the spindle. At least one non-helically grooved roller is interposed radially between the spindle and the nut. A cage maintains the at least one roller in position radially between the spindle and the nut and supports the at least one roller for rotational motion. The nut is moved in longitudinally in a duty cycle responsive to transmission of rotational motion from the spindle to the at least one roller, and transformation of rotational motion of the at least one roller to longitudinal motion of the nut. A home position of the nut and a home position of the cage both move longitudinally after a predetermined number of duty cycles.

The disclosure relates to an actuator having a planetary roller screw drive comprising a housing having a cylinder chamber and a fluid reservoir forming one common volume and the housing is filled with a hydraulic fluid. The planetary roller screw drive comprises a spindle having a profiling, which meshes with a plurality of planetary rollers, which are arranged around the spindle and are supported at both ends in a planetary roller carrier. The planetary rollers mesh with an inner profiling of an internal ring gear surrounding the planetary rollers and the planetary rollers are supported in a sleeve surrounding the internal ring gear. According to the disclosure, the planetary roller carrier and/or the sleeve comprise one or more flow ducts connecting the interior and the exterior of a chamber defined radially by the sleeve and axially by the planetary roller carriers to one another.

The present disclosure relates to the technical field of aerial work platforms, in particular to a linear actuator with a contact type safety nut, and an aerial work platform. The linear actuator includes a central screw, a driving nut mechanism, and a safety nut mechanism. The central screw has a screw raceway. The safety nut mechanism includes a safety nut seat sleeved at the periphery of the central screw. Limit hole channels pointing to the central screw are arranged on the safety nut seat. An elastic buffer element is arranged in each of the limit hole channels. A safety ball is arranged between the elastic buffer element and the central screw. The contact type safety nut enables the linear actuator to always keep safety, stability, and no loss of accuracy in a conversion process that the safety nut mechanism gets involved to take effect while the driving nut mechanism fails.

An actuator for providing a thrust force over a determined travel, comprising a nut, a screw, a sleeve configured to surround the screw in an axial direction (X-X) of the screw, a plurality of rollers, the nut being configured to cooperate with the screw, the nut being secured to the rollers, which are free to rotate, the rollers being configured to each move in particular in the one of at least one helical guide or the sleeve, the screw being configured in order, when it is turned, to operate the actuator, to rotate the nut when it bears via the rollers on a profile of the helical guide and to thus advance in the axial direction (X-X) of the screw at greater or lesser speed along a slope of the profile of the helical guide. The actuator further comprises a motor configured to turn the screw. Successive values of the slope all along the profile or profiles of respectively the one or more helical guides ae adapted to ensure that the slope systematically compensates for at least one peak of the desired thrust force in order to carry out clipping of the maximum values of the thrust force such that the motor, the screw and the nut are dimensioned to a motor torque value corresponding to the value of the thrust force after clipping.

The disclosure relates to an actuator having a planetary roller screw drive comprising a housing having a cylinder chamber and a fluid reservoir forming one common volume and the housing is filled with a hydraulic fluid. The planetary roller screw drive comprises a spindle having a profiling, which meshes with a plurality of planetary rollers, which are arranged around the spindle and are supported at both ends in a planetary roller carrier. The planetary rollers mesh with an inner profiling of an internal ring gear surrounding the planetary rollers and the planetary rollers are supported in a sleeve surrounding the internal ring gear. According to the disclosure, the planetary roller carrier and/or the sleeve comprise one or more flow ducts connecting the interior and the exterior of a chamber defined radially by the sleeve and axially by the planetary roller carriers to one another.

The present disclosure relates to the technical field of aerial work platforms, in particular to a linear actuator with a contact type safety nut, and an aerial work platform. The linear actuator includes a central screw, a driving nut mechanism, and a safety nut mechanism. The central screw has a screw raceway. The safety nut mechanism includes a safety nut seat sleeved at the periphery of the central screw. Limit hole channels pointing to the central screw are arranged on the safety nut seat. An elastic buffer element is arranged in each of the limit hole channels. A safety ball is arranged between the elastic buffer element and the central screw. The contact type safety nut enables the linear actuator to always keep safety, stability, and no loss of accuracy in a conversion process that the safety nut mechanism gets involved to take effect while the driving nut mechanism fails.

An actuator for providing a thrust force over a determined travel, comprising a nut, a screw, a sleeve configured to surround the screw in an axial direction (X-X) of the screw, a plurality of rollers, the nut being configured to cooperate with the screw, the nut being secured to the rollers, which are free to rotate, the rollers being configured to each move in particular in the one of at least one helical guide or the sleeve, the screw being configured in order, when it is turned, to operate the actuator, to rotate the nut when it bears via the rollers on a profile of the helical guide and to thus advance in the axial direction (X-X) of the screw at greater or lesser speed along a slope of the profile of the helical guide. The actuator further comprises a motor configured to turn the screw. Successive values of the slope all along the profile or profiles of respectively the one or more helical guides ae adapted to ensure that the slope systematically compensates for at least one peak of the desired thrust force in order to carry out clipping of the maximum values of the thrust force such that the motor, the screw and the nut are dimensioned to a motor torque value corresponding to the value of the thrust force after clipping.