Abstract: A numbering head particularly adaptable to a portable gun including a frame having flat surfaces for seating against a flat workpiece. A shaft is positioned parallel to the seating surfaces and is supported within elongated apertures which allow the shaft, and marking wheels disposed on the shaft, to move through a limited length of travel toward, and away from, the workpiece. Each marking wheel includes, about its periphery, marking characters separated by grooves, each groove being disposed directly across from a corresponding character. A generally T-shaped yoke is supported within the frame and is matingly shaped to the grooves in the wheels. Biasing springs acting between the yoke and frame force the yoke into contact with the marking wheel grooves. A portion of the yoke extends into, or through, an opening in the frame. The opening is threaded to provide attachment of the numbering head to a portable gun, or a fixed or portable press, and to align the hammer of the gun or press with the yoke.

Abstract: An impact device for use in machines, such as presses, for marking, punching, stamping, forming, riveting, and other related operations, wherein a convex edged member, such as a ball, axially separates a tool and a hammer, the hammer being loaded by compressible means such as a tension spring, all moveable axially within a moveable spindle. The ball is displaced radially into an adjoining magazine at the point of full extension of the spindle, after the tool is in contact with the workpiece, thereby allowing the spring loaded hammer to strike the tool, imparting an impact force to the workpiece.