A vehicle-mounted electric oil-free air compressor, including a motor, a box body, a piston, and a flywheel shaft. The motor is fixed on the box body, a cylinder cover is at the top of the box body, a main shaft of the motor includes a coupling driving end, the flywheel shaft is driven by an elastic body to rotate. The piston includes a primary intake valve piece and a primary exhaust valve piece, the box body is provided with a secondary cavity, a secondary exhaust valve piece is provided at a vent hole on one side of the cavity, and the primary exhaust valve piece is also a secondary intake valve piece of the compressor, increasing the exhaust pressure. When the piston reciprocates, the stress is balanced and the vibration is small, and with the assistance of a high-efficiency flywheel, the operation of the air compressor is stable.

A balance weight includes a main weight portion extending over a range defined by a circular-arc circumferential edge centered at a rotational shaft hole side and a pair of virtual end surfaces located on the circular-arc circumferential edge on both sides of the rotational shaft hole, a pair of extension weight portions extending from the pair of virtual end surfaces to an opposite circular-arc side of the rotational shaft hole from the circular-arc circumferential edge, the rotational shaft hole provided at the main weight portion so as to be located on a central side of the circular-arc circumferential edge, a crank shaft attachment protrusion, a crank shaft hole provided at the crank shaft attachment protrusion radially eccentrically with respect to the rotational shaft hole, and a pair of spaces formed between positions on both sides of the crank shaft attachment protrusion and the pair of extension weight portions, respectively.

A power-driven reciprocating tool may include a transmission mechanism that converts rotational force from a motor to linear force to be output by a reciprocating mechanism coupled thereto, and a counterbalancing mechanism coupled to the transmission mechanism to counter-balance forces generated by the reciprocating mechanism. The transmission mechanism may include a planetary gear assembly including a sun gear in meshed engagement with at least one planet gear. In response to a force converted by and transmitted from the transmission mechanism, the reciprocating mechanism may move in a first linear direction, and the counterbalancing mechanism may move in a second linear direction, opposite the first linear direction. The opposite linear movement of the reciprocating mechanism and the counterbalancing mechanism may counteract forces generated by the reciprocating motion of the reciprocating mechanism, thus reducing vibration output by the tool.

A power-driven reciprocating tool may include a transmission mechanism that converts rotational force from a motor to linear force to be output by a reciprocating mechanism coupled thereto, and a counterbalancing mechanism coupled to the transmission mechanism to counter-balance forces generated by the reciprocating mechanism. The transmission mechanism may include a planetary gear assembly including a sun gear in meshed engagement with at least one planet gear. In response to a force converted by and transmitted from the transmission mechanism, the reciprocating mechanism may move in a first linear direction, and the counterbalancing mechanism may move in a second linear direction, opposite the first linear direction. The opposite linear movement of the reciprocating mechanism and the counterbalancing mechanism may counteract forces generated by the reciprocating motion of the reciprocating mechanism, thus reducing vibration output by the tool.

Provided is a method to acquire the unbalance of a rotor and a balancing machine, in which, the method to acquire the unbalance of a rotor includes the following procedures: install angle sensor at first position on balancing machine, measure the unbalance of rotor, first unbalance in measuring plane 1 and first unbalance in measuring plane 2 can be measured. Move angle sensor on balancing machine from first position to second position, measure the unbalance of the rotor again, second unbalance in measuring plane 1 and second unbalance in measuring plane 2 can be measured. In the above mentioned two measurements, the unbalance amount of rotor has no change, but the unbalance angle relative to angle reference point on rotor is changed by an angle which equals the angle of the sensor being moved.

A dynamic balancing apparatus includes a dynamic balancing assembly and a plurality of damping particles. The dynamic balancing assembly includes at least two structural members separately arranged on a rotating shaft connected to a rotor, wherein each structural member includes at least one recess portion. The plurality of damping particles are introduced into at least one recess portion of each structural member, such that a centroid of each structural member deviates from the axis. Accordingly, each structural member generates inertial force and moment of inertia as rotation of the rotor to offset another inertial force and moment of inertia generated by centroid deviation of the rotor while rotating to achieve dynamic balance. The plurality of damping particles can move in the recess portion as rotation of the rotor to induce friction and collision so as to achieve the effects of vibration reduction and noise reduction.

An attachment to photographic tripod to easily attach and tension a rope that is attached on the opposite end to a weight or ballast. This weight or ballast will add stability to the tripod. In many instances a photographer will have a camera bag that will provide the necessary weight or ballast. The three tapered slots allow a rope to be quickly and easily wound through the preferred embodiment of the invention and the weight is tensioned and secured just by pulling down on the rope and engaging it further down into the tapered slots.

An attachment to photographic tripod to easily attach and tension a rope that is attached on the opposite end to a weight or ballast. This weight or ballast will add stability to the tripod. In many instances a photographer will have a camera bag that will provide the necessary weight or ballast. The three tapered slots allow a rope to be quickly and easily wound through the preferred embodiment of the invention and the weight is tensioned and secured just by pulling down on the rope and engaging it further down into the tapered slots.

The present disclosure shows a crankshaft having at least one counterweight that is preferably screwed to the crankshaft via at least two screws, with the counterweight having a contact surface at which it contacts a counter-contact surface of the crankshaft. In this respect, the position of the counterweight at the crankshaft is fixed via at least one positioning element independent of the screw connection.

A machine tool having a drivetrain, which includes a tool shaft rotatably mounted on a drive support by means of a bearing assembly and a tool holder arranged on the tool shaft, wherein the tool shaft is rotationally drivable by a drive motor of the machine tool around a rotational axis, and wherein a balancing device is arranged on the tool shaft, which includes a guide body having at least one orbital path extending around the rotational axis and at least one balancing body movably mounted in the orbital path.