Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.

A vibration isolating coupler including a first coupler portion, a second coupler portion including an external surface and an internal surface portion, and a vibration isolating portion extending between the first coupler portion and the second coupler portion. The vibration isolating portion including a first solid annular portion and a second solid annular portion. The vibration isolating portion including a plurality of slots extending from the first solid annular portion toward the second solid annular portion forming a plurality of vibration isolating elements. Each of the plurality of vibration isolating elements is disconnected from adjacent ones of the plurality of vibration isolating elements by a corresponding one of the plurality of slots. The plurality of vibration isolating elements enabling torsional rotation of the first coupler portion relative to the second coupler portion.

A torque converter, including: a cover; an impeller including an impeller shell connected to the cover and at least one impeller blade; a turbine in fluid communication with the impeder and including a turbine shell and at least one turbine blade; stator including at least one stator blade; and a vibration damper including a first cover plate, a second cover plate non-rotatably connected to the first cover plate, an intermediate flange axially disposed between the first cover plate and the second cover plate, at least one spring directly engaged with the first cover plate, the second cover plate, and the intermediate flange, and a resilient element directly engaged with the first cover plate and the intermediate flange and urging the intermediate flange in an axial direction, parallel to an axis of rotation of the torque converter, away from the first cover plate and into contact with the second cover plate.

A pulley structure may be equipped with an outer rotating body, an inner rotating body, and a coil spring provided between the outer rotating body and the inner rotating body. The coil spring is configured so as to undergo torsional deformation in a diameter-expanding or a diameter-contracting direction, thereby engaging the outer rotating body and the inner rotating body and transmitting torque, and to undergo torsional deformation in the direction opposite the direction in which torque is transmitted, thereby entering a disengaged state in which the coil spring slides with the outer rotating body or the inner rotating body, thus interrupting the transmission of torque. The number of windings of the coil spring is in a range between [M-0.125] and M (both inclusive), where M is a natural number.

A plug (1) for use with a counterbalancing system (3) of a cable-operated door (5). The plug (1) includes flange and collar portions (13,15), the flange portion (13) being connectable to a mounting component (7) of the counterbalancing system (3) in order to allow a torque transfer from a torsion spring (9) to the mounting component (7), and the collar portion (15) being configured for winding into a given end (17) of the torsion spring (9), the collar portion (15) having opposite first and second extremities (19,21), and an outer surface (23) extending between these extremities (19,21), the outer surface (23) of the collar portion (15) being provided with a plurality of threads (25) and a plurality of corresponding recesses (27) each being defined between a pair of adjacent threads (25), each recess (27) being configured for receiving therein a single coil segment (11a) of the torsion spring (9), and being further shaped and sized for preventing another coil segment (11b) of the torsion spring (9) from embarking onto said recess (27).

A torsion spring adjustment assembly for supporting a finger wheel rake that includes a lever operably connected to a torsion spring supporting the finger wheel rake for setting the tension of the torsion spring. The lever is pivotable about the axis of a rotational shaft of the finger wheel rake to a plurality of tension-setting positions and is secured to a main frame of the finger wheel rake at a position selected from the plurality of tension-setting positions. The lever is adjusted to a select position and then secured against the adjustment plate by a mechanical fastener.

A method includes, providing a tubular member (10) used for a hollow spring, and applying the compressive residual stress to at least a portion of an inner surface of the steel tube by applying the compressive force to at least a portion of an outer surface of the tubular member (10) from a circumferential direction, and a fatigue life of the tubular member (10) is prolonged by applying the compressive residual stress to the inner surface of the tubular member (10). Applying the force to the outer surface of the tubular member (10) includes pressing the tubular member (10) with a die (1). The die (1) has a pressing surface (1a) shaped such that the compressive force can be applied to at least the portion of the outer surface of the tubular member (10) from the circumferential direction.

A torsion spring used in a flexible display device includes a spring body having a first connection end configured to connect a reel of the flexible display device, and a second connection end configured to fix the torsion spring. An axial sectional area of the spring body near the first connection end is greater than an axial sectional area of the spring body away from the first connection end. When the reel rotates, the torsion force generated during the initial rotation of the reel is relatively large, and with the increase of the rotation turn number of the reel, the increase of the torsion force is relatively small.

A drive train assembly (200) for a personal care device (10), comprising a torsion spring (210) suspended between a first end mount (220) and a second end mount (230), the torsion spring comprising a first end mounted to the first end mount and a second end mounted to the second end mount, wherein the first and second ends of the torsion spring each comprises a cross flexure spring hinge (250, 260).