Abstract: A valve operator assembly is provided for a valve. The assembly includes a housing adapted to be mounted on a bonnet of the valve, an input member rotatably mounted with respect to the housing and an inverted roller screw mechanism and comprising a screw adapted to be connected to a valve stem of the valve, a nut surrounding and coaxial with the screw, the nut being connected to the input member, and a plurality of rollers radially disposed between the screw and the nut.

Abstract: A screw mechanism comprising a screw provided with an outer thread, a nut surrounding and coaxial with the screw, the nut being provided with an inner thread, and a plurality of rolling elements radially disposed between the screw and the nut and engaged in both of the outer and inner threads. A contact diameter Dcontact between the rolling elements and the nut is defined by: D contact ? L ? × tan ? ( ? ) wherein L corresponds to the lead of the screw mechanism and ? corresponds to a determined non-back-driving factor which is chosen from 0°<??1°. The contact diameter is provided in order to prevent back-driving of the mechanism.

Abstract: The roller screw mechanism is provided with a screw including an external thread, with a nut arranged about and coaxial with said screw, the nut including an internal thread, and with a plurality of rollers inserted between the screw and the nut and each including an external thread engaging the external and internal threads of said screw and of said nut. The screw is axially moveable in relation to the rollers. The flanks of the thread of the screw have a concave profile in cross section.

Abstract: A bearing lubricating housing (100) comprising a lubricating housing body (110). The bearing housing (100) is designed to retain a rolling element bearing assembly (200) while providing axial motion when the housing (100) is assembled within an interior of a guiding tube (310). The bearing housing (100) includes a series of channels (118) and/or passageways (114, 116) forming a lubrication matrix for collecting a lubricant from an interior surface (312) of the guiding tube (310) to the rolling element bearing assembly (200).

Abstract: An anti-rotation device prevents relative rotation between first and second members, one member being telescopingly disposed about the other and at least one member being linearly displaceable along a central axis. First and second guide surfaces are provided on the first member and extend generally parallel with each other and the central axis. First and second rollers are connected with the second member and are each rotatable about an adjustably fixed axis on the second member. The first roller is rollable along the first guide surface to prevent angular displacement between the two members when the displaceable member moves in a first direction and the second roller is rollable along the second guide surface to prevent angular displacement between the two members when the displaceable member moves in an opposing direction. The contact between the rollers and guide surfaces provide a radial degree of freedom to the anti-rotation device.

Abstract: A bearing lubricating housing (100) comprising a lubricating housing body (110). The bearing housing (100) is designed to retain a rolling element bearing assembly (200) while providing axial motion when the housing (100) is assembled within an interior of a guiding tube (310). The bearing housing (100) includes a series of channels (118) and/or passageways (114, 116) forming a lubrication matrix for collecting a lubricant from an interior surface (312) of the guiding tube (310) to the rolling element bearing assembly (200).

Abstract: The roller screw mechanism is provided with a screw comprising an external thread, with a nut arranged around and coaxial with the said screw, the nut comprising an internal thread, and with a plurality of rollers interposed between the screw and the nut and comprising flanks interacting with the said threads. The value of the opening angle ? of the flanks of the external thread of the screw is greater than the value of the opening angle of the flanks of the rollers.

Abstract: The roller screw mechanism is provided with a screw including an external thread, with a nut arranged about and coaxial with said screw, the nut including an internal thread, and with a plurality of rollers inserted between the screw and the nut and each including an external thread engaging the external and internal threads of said screw and of said nut. The screw is axially moveable in relation to the rollers. The flanks of the thread of the screw have a concave profile in cross section.

Abstract: The roller screw mechanism is provided with a screw comprising an external thread, with a nut arranged around and coaxial with the said screw, the nut comprising an internal thread, and with a plurality of rollers interposed between the screw and the nut and comprising flanks interacting with the said threads. The value of the opening angle ? of the flanks of the external thread of the screw is greater than the value of the opening angle of the flanks of the rollers.