A rammer includes: an outer cylinder (31); an inner cylinder (32) slidably contacted with an inside of the outer cylinder (31); a slider (33) connected to a connecting rod (14) and slidably provided in the inner cylinder (32); a first coil spring (34) housed in the upper part of the inner cylinder (32); and a second coil spring (35) housed in the lower part of the inner cylinder (32), wherein the slider (33) is disposed between the first coil spring (34) and the second coil spring (35), wherein a crank shaft has a rotational axis disposed orthogonally to the moving direction, and the first coil spring (34) and the second coil spring (35) have respectively different winding directions to each other.

A rammer includes: an outer cylinder (31); an inner cylinder (32) slidably contacted with an inside of the outer cylinder (31); a slider (33) connected to a connecting rod (14) and slidably provided in the inner cylinder (32); a first coil spring (34) housed in the upper part of the inner cylinder (32); and a second coil spring (35) housed in the lower part of the inner cylinder (32), wherein the slider (33) is disposed between the first coil spring (34) and the second coil spring (35), wherein a crank shaft has a rotational axis disposed orthogonally to the moving direction, and the first coil spring (34) and the second coil spring (35) have respectively different winding directions to each other.

A stand-alone motor unit includes a housing and an electric motor. The electric motor includes a stator, a rotor rotatable relative to the stator and having an output shaft, a housing in which the stator and rotor are arranged, and an adapter plate coupled to the housing. The adapter plate includes a first plurality of holes defining a first hole pattern. The output shaft of the rotor protrudes from the adapter plate. The motor unit further includes a battery pack for providing power to the motor, a power take-off shaft protruding from the housing, and a gearbox including a second plurality of holes defining a second hole pattern that is identical to the first hole pattern, such that when the first hole pattern is aligned with the second hole pattern, the gearbox is configured to be coupled to the adapter plate.

A ground compacting device having a ground leveling plate and a motor for driving the ground leveling plate includes a support portion attached to an upper half of the ground compacting device via an anti-vibration member separately from a handle, and an electrical component for driving the motor is attached to the support portion.

A ground compacting device having a ground leveling plate and a motor for driving the ground leveling plate includes a support portion attached to an upper half of the ground compacting device via an anti-vibration member separately from a handle, and an electrical component for driving the motor is attached to the support portion.

The present invention provides a motor apparatus having a motor, comprising: a fan that is rotatably supported by a shaft member of the motor, and sends, in a centrifugal direction by rotation, gas taken from an axial direction of the shaft member; and a cover member that covers the fan so as to allow the gas sent in the centrifugal direction from the fan to flow along an outer surface of the motor, wherein the cover member has a blowout port that blows out some of the gas sent in the centrifugal direction from the fan in the centrifugal direction to cool an external mechanism of the motor apparatus.

A compactor includes a plate, a shaft rotatably supported upon the plate, an electric motor configured to cause rotation of the shaft, and an eccentric mass arranged to rotate on the shaft, causing the plate to vibrate in response to rotation of the eccentric mass. The eccentric mass is configured to translate along the shaft.

A compactor includes a plate, an electric motor coupled to the plate, an exciter coupled to the plate and configured to vibrate the plate in response to receiving torque from the electric motor, a means for transferring torque from the electric motor to the exciter, a battery configured to provide power to the electric motor, and a vibration isolator coupling the battery to the plate.

An apparatus for steering and driving a concrete screed having a frame and a screed head secured thereto includes a plurality of spaced drive wheels rotatably and pivotably secured to the frame at a plurality of points, and a steering member coupled to one or more of the drive wheels for controlling the directional orientation thereof.

An unbalance exciter for a soil compaction device comprises at least two rotatable unbalance masses which are rotatably mounted in opposite directions relative to each other, and at least two rotors. Each of the unbalance masses is coupled to a respective one of the rotors. The at least two unbalance masses and the associated rotors are mounted coaxially relative to each other. A stator is associated with each of the rotors in such a way that each rotor and the associated stator form an electric motor.