US Patent 7497705 Lockout device

A lockout device is provided for an electrical plug. The device includes a body and a retaining member disposed within the body and axially movable between a prong retaining position and a prong releasing position. The retaining member includes a prong engaging portion and a prong retaining portion. The prong engaging portion is configured to engage at least one of the first and second prongs when the first prong is inserted in the first slot for movement of the retaining member from the prong releasing position to the prong retaining position. The prong retaining portion is configured to extend through the first transverse aperture when the first prong is inserted in the first slot, and is configured to withdraw from the first transverse aperture when the first prong is pulled from the first slot.