Patent ID: 7340982
Filing Date: 2008-03-11
Classification: B25B

Abstract:
1. A symmetrical open-end wrench with a fastener-engaging opening having an axis of symmetry, said wrench comprising: fastener-engaging surfaces comprising forwardly disposed substantially planar sections extending parallel to and on opposite sides of said axis of symmetry; rear side corners of said opening, said rear side corners comprising arcs that curve outwardly from a geometric projection of said respective substantially planar sections and away from said axis of symmetry, for reducing or eliminating stress concentrations at said rear side corners; a throat interconnecting said rear side corners, said throat having a configuration of a “U” on the axis of symmetry, said “U” configuration having opposing relatively large internal curved corners and an internal central portion between said latter corners, said “U” configuration being modified with material being included in said opposing relatively large internal corners and said central portion of the “U” to create relatively small internal corners to improve the strength of said wrench compared to a wrench absent said included material, said central portion having a higher degree of concavity than the remainder of said throat; and outwardly diverging sections being disposed between said substantially planar sections and said rear side corners of said opening, said diverging sections diverging both from the respective planar sections and from said rear side corners of said opening, and being located on opposite sides of said axis of symmetry and extending away from said axis of symmetry from the front towards the rear of said outwardly diverging sections, said diverging sections including irregularities that grip a fastener in said opening and having smooth cornerless surfaces merging with said rear side corners.