In an aspect, a torsional vibration damper is provided, comprising a hub portion that mounts to a crankshaft, an outer ring that includes an inertial mass, a plurality of radial connectors that are elastically deformable and a plurality of spacers that extend circumferentially between the radial connectors and which are elastically deformable by the radial connectors during flexure thereof. The spacers are non-metallic and dissipate energy from deformation via conversion to heat. The plurality of radial connectors have a circumferential spring rate K1a in bending in a circumferential direction about the axis, and have an axial spring rate K1b in bending in an axial direction, wherein K1b is at least 10 times as large as K1a. The plurality of spacers have a circumferential spring rate Kra in the circumferential direction, and an axial spring rate Krb in bending in the axial direction, wherein Kra is less than 1% of K1a.

The present invention relates to a pulley structure (1) equipped with an outer rotating body (2), an inner rotating body (3), and a coil spring (4) provided between the outer rotating body (2) and the inner rotating body (3). The coil spring (4) is configured so as to undergo torsional deformation in a diameter-expanding or a diameter-contracting direction, thereby engaging the outer rotating body (2) and the inner rotating body (3) 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 (2) or the inner rotating body (3), thus interrupting the transmission of torque. The number of windings of the coil spring (4) is in a range between [M-0.125] and M (both inclusive), where M is a natural number.

A torque adjustment mechanism is provided for use with a torsion spring. The torsion spring is a coil spring having a plurality of helical coils that define a hollow core. A torque adjuster is positioned in the interior of the hollow core of the coil spring. The torque adjuster has a circular collar on one end and a securing flange on the other end. The circular collar is designed to fit into the hollow core of the coil spring. A clamp is positioned over the exterior of the coil spring in alignment with the circular collar. The clamp secures the coil spring to circular. The position of the collar in the spring defines the number of the coils that are active and establishes the level torque provided by the torsion spring.

A fastener driving tool includes a housing, a striking member, an energy storing unit and a handle unit. The energy storing unit has a torsion spring which has weighted and driving legs extending from two ends of a coil. The driving leg is biased against and engaged with the weighted leg to be preloaded with a downward potential energy that urges a downward movement of the torsion spring and the striking member. The handle unit includes a handle and an anchoring member removably engaged with the striking member. When the handle is pivotally moved from a ready position to a striking position, the weighted leg is moved downwardly and the anchoring member and the striking member are moved upwardly to gradually increase a loading of the torsion spring for the striking member.

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.

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 3D printed additively manufactured (AM) elliptical bifurcating torsion flexure assembly system includes a base section; elliptical bifurcating torsion springs, each including a bifurcated legs section supported by the base; a bifurcated elliptical torsion spring section contiguous with the bifurcated legs section; and a single upper section contiguous with the elliptical torsion spring section. The single upper section includes a connection component, and the device material includes Hot Isostatic Pressing (HIP) heat-treated Ti6Al4V. The elliptical bifurcating torsion flexure assembly is printed as one part by a 3D additive manufacturing process, and the bifurcation maintains consistent balance while being torqued. The stiffness-spring rate of the device is at least partly controlled by varying cross-sectional shape and diameters by the 3D additive manufacturing printing.

A hollow spring member and hollow spring member production method can be provided, which can save the time and energy necessary for carburization, thus requiring no dedicated carburizing furnace or the like for carburization, and further can make the interior space of a steel tube a rust-prevention atmosphere. A hollow stabilizer for a vehicle includes a steel tube sealed at one end and another end thereof and a carburizing gas sealed in the interior space of the steel tube.

A reel damper includes a base, a cap, a ring gear, a torsion spring, and a sun gear. The cap is secured to the base, and the ring gear is rotatably engaged with the base. The torsion spring is engaged with the base and the ring gear. The sun gear is disposed in and meshed with the ring gear.