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 valve operator assembly is provided for a valve and comprises a housing 18, an input member 20 rotatably mounted with respect to said housing and comprising a rotational drive input 72, and a transmission mechanism 22 connected to said input member and comprising a stem 24, said transmission mechanism being adapted to convert applied rotation of the rotational drive input into axial translation of said stem. The assembly further comprises at least one elastic actuator 33 axially located between the input member 20 and the stem 24 to obtain a compression of the actuator during an axial translation of said stem towards the input member and a release of said actuator during an axial translation in the opposite direction.

Abstract: A roller screw mechanism comprising a screw having an outer thread, a nut disposed around and coaxially with the screw. The nut includes an inner thread. A plurality of rollers are disposed radially between the screw and the nut and are each provided with an outer thread engaged with the outer and inner threads of the screw and of the nut and with two outer gear teeth. The mechanism additionally comprises two synchronizing gear teeth that are formed on the nut and are each engaged with one of the gear teeth of the rollers. The root diameter of each gear teeth is less than the inside diameter of the inner thread of the nut.

Abstract: A roller screw mechanism comprising a screw, provided with an outer thread, a nut positioned around and coaxially to the screw, the nut being provided with an inner thread, and a plurality of rollers inserted between the screw and the nut, each comprising an outer thread engaged with the outer thread of the screw and with the inner thread of the nut. Each of the threads of the screw, rollers and nut comprise first and second axially opposite flanks, respectively forming a first and second angle with a plane perpendicular to the central axis of the screw, the first and second flanks of each thread of the rollers respectively being in contact with the first and second flanks of the nut's thread and with the first and second flanks of the screw's thread. The value of the first angle is different from the value of the second angle.

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 system comprises a roller screw mechanism 12 which is provided with a screw 16 which comprises at least a first outer threaded portion 18, a nut 20 and a plurality of rollers 24 which cooperate with the first outer portion 18 and an inner thread of the nut. The system further comprises a roller thrust bearing 14 which is mounted on a second outer portion 52 of the screw and which is provided with a bushing 50 and a plurality of rollers 56 which comprise flanks which cooperate with flanks of the second outer portion 52 of the screw and the bushing 50. The flanks of the screw, the bushing and the rollers are configured so that, during a rotation of the screw, the rollers 56 are fixed axially relative to the screw 16 and relative to the bushing 50.

Abstract: Actuating device comprising a longitudinal shaft (2), an intermediate tailstock spindle (3), an outside sleeve (4), internal thread means (5) making it possible to connect the longitudinal shaft and the intermediate tailstock spindle to generate an axial movement of one with respect to the other, external thread means (6) making it possible to couple the intermediate tailstock spindle and the outside sleeve and suitable for generating an axial movement of one with respect to the other, the said internal coupling means comprising internal roller elements (7) engaged on the one hand with the external and internal threads of the intermediate tailstock spindle and/or the said external coupling means comprising external roller elements (25) engaged on the one hand with the external thread of the intermediate tailstock spindle and the internal thread of the outside sleeve and comprising coupling means making it possible to couple the shaft and the intermediate tailstock spindle or the intermediate tailstock spindle

Abstract: Actuating device comprising a longitudinal shaft (2), an intermediate tailstock spindle (3), an outside sleeve (4), internal thread means (5) making it possible to connect the longitudinal shaft and the intermediate tailstock spindle to generate an axial movement of one with respect to the other, external thread means (6) making it possible to couple the intermediate tailstock spindle and the outside sleeve and suitable for generating an axial movement of one with respect to the other, the said internal coupling means comprising internal roller elements (7) engaged on the one hand with the external and internal threads of the intermediate tailstock spindle and/or the said external coupling means comprising external roller elements (25) engaged on the one hand with the external thread of the intermediate tailstock spindle and the internal thread of the outside sleeve and comprising coupling means making it possible to couple the shaft and the intermediate tailstock spindle or the intermediate tailstock spindle

Abstract: A screw actuator comprises a nut and a screw each comprising helical grooves, said nut and screw engaging each other by rollers or balls which are in contact with said grooves, a lubricant being provided for the grooves and rollers or balls. Integrated in the actuator is a module, which is connected to at least the helical grooves of the nut and/or screw for replenishing the lubricant for the grooves and rollers or balls of the actuator.

Abstract: A screw actuator comprises a screw (1) and a nut (2) which are each provided with at least a helical groove (3,4), and a series of rollers or balls (5) which are in rolling contact with the grooves (3,4). A sleeve (6) is provided which surrounds the nut (2) at least partly. The sleeve (6) may carry a seal (7) which acts between the nut (2) and screw (1); e.g. a wiper seal. The seal (7) may be fixedly connected to the nut (2), and frictionally engage the screw (1).

Abstract: Calcium diacetone-2-ketogulonate, which is a new therapeutically useful compound.

Abstract: Calcium diacetone-2-ketogulonate, which is a new therapeutically useful compound.