Abstract: A hammer handle is made of a spring strip formed into an oblong closed figure and a synthetic resin handle body molded around the frame. The closed figure is interrupted at one point along the front longitudinal side. Abutment of the free ends at the discontinuity prevents the frame and thus the handle from flexing in one direction when the hammer claw is used, but the free ends part to permit the handle to flex in the other direction and thereby reduce the shock resulting from striking a workpiece.

Abstract: A hammer of the type that includes a column of vertebra members is made of vertebra members having mating upper and lower abutment surfaces. Parts of adjacent abutment surfaces are mating concave and convex surfaces that slide across each other during pivoting in one direction so that the length of the shaft passage through the vertebra members is not increased during flexing of the hammer. Another portion of each abutment surface requires lengthening of the shaft passage if the vertebrae are to pivot in the other direction. Consequently, a shaft extending through the shaft passage and fixed at its upper and lower ends to the head and handle, respectively, prevents flexing in one direction but not in the other. Furthermore, the overwhelming majority of the resistance to flexing is provided by the shaft, not by interference between vertebra members, so the shaft size for a given resistance to flexing can be relatively large.