The present invention provides a spring mechanism which can elastically deform an elastic deformation part with a film shape of a transducer into a shape having high symmetry, and also can be structured in a small size. A spring mechanism 2 includes: a cylindrical member 7 that is provided so as to extend toward a first element member 21 from an elastic deformation part 11 of a transducer 5, and also is arranged so as to slidably penetrate the first element member 21 in the direction of a central axis line C of the elastic deformation part 11; and a rod member 32 that is provided so as to extend toward the cylindrical member 7 from a second element member 22 side, and is slidably inserted in the cylindrical member 7 in the direction of the central axis line C of the elastic deformation part 11.

A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

In at least one embodiment, a rotational spring is provided with adjustable stiffness and includes at least one beam arranged about an axis between an input tuning port and an output port, wherein the input tuning port is configured to change an effective bending length of at least one beam so as to change a shear stiffness with respect to the input tuning port and the output port.

In at least one embodiment, a rotational spring is provided with adjustable stiffness and includes at least one beam arranged about an axis between an input tuning port and an output port, wherein the input tuning port is configured to change an effective bending length of at least one beam so as to change a shear stiffness with respect to the input tuning port and the output port.

A leaf spring device includes a main leaf made of a steel plate including an elastic section configured to generate elastic force when bent; and an eye section formed in an end portion of the elastic section, the elastic section and the eye section being tempered. There is also provided a method for manufacturing the leaf spring device. The eye section is formed by rolling the end of the elastic section into a circular form. The eye section is tempered at a higher temperature than the elastic section.

In one embodiment, a vibration control apparatus is provided having a pair of face sheets with a core material in between. The core material comprising a positive stiffness material. A stack comprising a positive stiffness structure in series with a negative stiffness structure is located between the pair of face sheets, in parallel with the core material. The stack may be embedded in the core material. Various embodiments may include multiple stacks in parallel with each other. In some embodiments, the stack may include multiple positive stiffness structures in series with multiple negative stiffness structures. The multiple positive stiffness structures and negative stiffness structures may be interleaved.

A torsional damper for a torque transmission device, comprising: a first element (1) and a second element (2) rotationally movable with respect to one another; and a first damping means and a second damping means, each damping means comprising: an elastically deformable blade (9) having a fastening portion (12) and an elastic portion (13), an abutment element carried by the other of the first and second elements and configured, for an angular deflection between the first and second elements with respect to an inactive angular position, to apply a flexural load onto the blade,
the elastic portion of the blade of the first damping means proceeds circumferentially beyond the fastening portion of the blade of the second damping means.

A C-spring contains an inner spring that is spaced apart from the outer primary spring. In one example usage, the upper and lower legs of the C-spring have rear regions respectively configured for being mounted to a tubular frame tool frame member of a ground working implement, such as a disk, and to a bearing housing.

A leaf spring (100) comprises at least two spring arms (120, 130) and an inner fixing hole (110). The at least two spring arms (120, 130) are evenly distributed around a center of the inner fixing hole (110); each spring arm is of the same structure, and an outer fixing hole (122) is disposed at an outermost end of each spring arm. Further provided are a leaf spring group and a compressor. The leaf spring group comprises multiple leaf springs, and the compressor comprises the leaf spring group. The provided leaf spring has a structure of multiple concentric circular arms or a structure of concentric vortex arms, and the leaf spring has smaller equivalent mass, so that the rigidity and inherent frequency requirements can be met without the need of increasing the mass of the components, thereby reducing the product mass and saving the cost.