Patent 8720765 was granted and assigned to Hitachi on May, 2014 by the United States Patent and Trademark Office.
According to an aspect of the present invention, there is provided a nailing machine including: a housing; a motor that is accommodated in the housing; a plunger that plunges a nailing member; and a spring that is expanded or compressed by the motor to store an elastic energy therein and that accelerates the plunger by releasing the elastic energy, wherein a spring constant of the spring at one end of the spring in an expanding/compressing direction is set smaller than that of the spring at a center in the expanding/compressing direction.