Patent ID: 7788994

Claim:
A symmetrical open-end wrench for receiving fasteners having polygonal heads, said wrench having a front portion, a rear portion, a cavity and an axis of symmetry, said wrench comprising: a throat, said throat having the 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; a pair of spaced apart jaws on opposite sides of said axis of symmetry and connected to said throat, said jaws including: front ends spaced apart with respect to the axis of symmetry to define an opening to the cavity of said wrench, said spaced apart front ends defining a forward open end; planar, fastener-engaging sections extending rearwardly from the respective front ends of said jaws, said planar sections having rearward ends and being spaced apart with respect to the axis of symmetry and being parallel to each other; rounded rear corners at the rearward portion of each of said diverging sections; outwardly curved diverging sections being disposed between said respective planar sections and said rounded rear corners, said outwardly curved diverging sections merging with the respective rearward ends of said respective fastener-engaging surfaces in a smooth first transition without any abrupt changes between said respective outwardly curved diverging sections and said respective fastener-engaging surfaces for reducing or eliminating stress concentrations at said first transition, said outwardly diverging sections diverging continuously from the rearward ends of said respective planar sections and extending rearwardly and merging with the forward ends of said respective rounded rear corners in a smooth second transition without any abrupt changes between said respective outwardly curved diverging sections and said respective rounded corners, said outwardly curved diverging sections having irregularities for engaging respective sides of a fastener received in the cavity of said wrench; and said throat being rounded and interconnecting said rounded rear corners, and planar sections each having a length extending beyond the front side corners of a fastener received in the cavity of said wrench with a corner of the fastener-engaging said throat.