A hand-held cutting tool includes a handle, an operating unit, and a dampening arrangement. The handle includes a stationary part and a flexible part pivotally attached to the stationary part. At least a portion of the operating unit is fitted to the flexible part and at least one part of the dampening arrangement is located in stationary part. The dampening arrangement includes a rod that connects the flexible part to the stationary part of the handle. The rod is connected to the stationary part by a flexible element configured to dampen vibrations of the operating unit relative to the handle. The rod is connected to the flexible part by a pivot pin configured to dampen the vibrations of the operating unit relative to the handle.

A hand-held cutting tool includes a handle, an operating unit, and a dampening arrangement. The handle includes a stationary part and a flexible part pivotally attached to the stationary part. At least a portion of the operating unit is fitted to the flexible part and at least one part of the dampening arrangement is located in stationary part. The dampening arrangement includes a rod that connects the flexible part to the stationary part of the handle. The rod is connected to the stationary part by a flexible element configured to dampen vibrations of the operating unit relative to the handle. The rod is connected to the flexible part by a pivot pin configured to dampen the vibrations of the operating unit relative to the handle.

A rolling vibration reduction device for an internal combustion engine includes: a main inertial system configured to rotate with a crankshaft of the internal combustion engine; a driving force transmission mechanism configured to transmit a rotational driving force of the crankshaft, a direction of the rotational driving force being reversed by the driving force transmission mechanism; and a sub-inertial system configured to rotate by the rotational driving force transmitted from the driving force transmission mechanism and to reduce rolling vibration of the internal combustion engine associated with rotation of the crankshaft by rotating in an opposite direction to the crankshaft. A torsional resonance frequency in the rolling vibration reduction device is set to a value higher than an explosion primary frequency at a maximum engine speed in a preset operating region of the internal combustion engine.

A method of balancing an assembly of a wheel and a tire, may include measuring a maximum-value position of RFV of a tire and marking the measured maximum-value position, as a tire reference position, measuring each of the internal runout and external runout of the wheel, extracting a primary component of a waveform of the measured internal runout and a primary component of a waveform of the measured external runout and setting the former and latter measured primary components to be internal and external runout waveforms, respectively, synthesizing the internal and external runout waveforms and marking a minimum-value position on a synthesis waveform resulting from the synthesizing, as a wheel reference position, and aligning the tire reference position on the tire and the wheel reference position on the wheel to have the same phase and assembling the wheel and the tire.

A method of balancing an assembly of a wheel and a tire, may include measuring a maximum-value position of RFV of a tire and marking the measured maximum-value position, as a tire reference position, measuring each of the internal runout and external runout of the wheel, extracting a primary component of a waveform of the measured internal runout and a primary component of a waveform of the measured external runout and setting the former and latter measured primary components to be internal and external runout waveforms, respectively, synthesizing the internal and external runout waveforms and marking a minimum-value position on a synthesis waveform resulting from the synthesizing, as a wheel reference position, and aligning the tire reference position on the tire and the wheel reference position on the wheel to have the same phase and assembling the wheel and the tire.

A vibration attenuator is configured for use on an aircraft rotor rotatable about a mast axis and has upper and lower weight assemblies, each comprising a weight with a center of gravity being a radial distance from the mast axis. The weight assemblies are configured for rotation together relative to the rotor at a selected angular rate about the mast axis, the weights being located on opposing sides of the mast axis. A first motor is configured for selective translation of one of the weight assemblies relative to the other weight assembly along the mast axis between a minimum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in the same plane, and a maximum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in different planes for producing a whirling moment about the mast axis.

A vibration attenuator for an aircraft has first and second coaxial spinners configured for rotation about a mast axis and relative to a rotor. Upper and lower weights of each spinner are spaced radially from the axis and positioned 180 degrees from each other about the axis. The weights of each spinner are spaced from each other a distance parallel to the mast axis, each weight rotating about the mast axis in a different plane. The spinners rotate together relative to the rotor at a selected angular rate and are selectively rotatable relative to each other between a minimum-moment configuration, in which the upper weight of each spinner is angularly aligned with the lower weight of the other spinner, and a maximum-moment configuration, in which the upper weights are angularly aligned and the lower weights are angularly aligned, producing a whirling moment about the mast axis as the spinners rotate.

A vibration attenuator is configured for use on an aircraft rotor rotatable about a mast axis and has upper and lower weight assemblies, each comprising a weight with a center of gravity being a radial distance from the mast axis. The weight assemblies are configured for rotation together relative to the rotor at a selected angular rate about the mast axis, the weights being located on opposing sides of the mast axis. A first motor is configured for selective translation of one of the weight assemblies relative to the other weight assembly along the mast axis between a minimum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in the same plane, and a maximum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in different planes for producing a whirling moment about the mast axis.

A rolling vibration reduction device for an internal combustion engine includes: a main inertial system configured to rotate with a crankshaft of the internal combustion engine; a driving force transmission mechanism configured to transmit a rotational driving force of the crankshaft, a direction of the rotational driving force being reversed by the driving force transmission mechanism; and a sub-inertial system configured to rotate by the rotational driving force transmitted from the driving force transmission mechanism and to reduce rolling vibration of the internal combustion engine associated with rotation of the crankshaft by rotating in an opposite direction to the crankshaft. A torsional resonance frequency in the rolling vibration reduction device is set to a value higher than an explosion primary frequency at a maximum engine speed in a preset operating region of the internal combustion engine.

A system for providing power to a vehicle includes a combustion engine having a low number of cylinders. A mechanically driven charging mechanism is attached to the combustion engine to provide pressurized air to the combustion engine and generate increased power. The combustion engine includes a 2nd order mass balance shaft that is operatively coupled to a crankshaft of the engine. The 2nd order mass balance shaft rotates at a higher speed than the crankshaft and counters inertial forces generated by the pistons of the engine. A compressor of the mechanically driven charging mechanism is attached to the 2nd order mass balance shaft, such that the mechanically driven charging mechanism is mechanically driven by rotation of the 2nd order mass balance shaft. The high speed of the 2nd order mass balance shaft drives the compressor of the mechanically driven charging mechanism.