Abstract: A rocker device includes a base having a rocker surface for rocking on a supporting surface, and a wheel device attached to the base and partially extendible out of the bottom of the base to selectively engage with the supporting surface. The base is rockable relative to the supporting surface when the wheel device is disengaged from the supporting surface, and the base is movable relative to the supporting surface when the wheel device is engaged with the supporting surface, such that the rocker device may be moved periodically on the supporting surface.

Abstract: A rocker device includes a base having a rocker surface for rocking on a supporting surface, and a wheel device attached to the base and partially extendible out of the bottom of the base to selectively engage with the supporting surface. The base is rockable relative to the supporting surface when the wheel device is disengaged from the supporting surface, and the base is movable relative to the supporting surface when the wheel device is engaged with the supporting surface, such that the rocker device may be moved periodically on the supporting surface.

Abstract: A socket wrench device is used to rotate a spark plug. The device includes a socket member with a socket to fit the spark plug. An endless series of ratchet teeth are provided on the socket member so as to engage with another endless series of ratchet teeth which are provided on a driving member. The driving member is retained on the socket member in such a manner that the ratchet teeth of the driving member are engaged removably with those of the socket member. An annular spring element is sleeved on the driving member so as to bias the two series of ratchet teeth to join together. When the device rotates the spark plug to an appropriate position in the cylinder of an internal combustion engine, an external torque which is applied to the device compresses the spring element, so that the ratchet teeth of the driving member are disengaged from those of the driving member, thereby stopping the rotation of the spark plug relative to the cylinder.