US Patent 7146884 High torque open end wrench

An open end wrench for use with a fastener having a polygonal gripping portion has an elongated body, a first jaw having a first bite surface and a second jaw having a second bite surface. The jaws form a throat therebetween having a closed end and an open end. The bite surfaces are disposed with engaging surfaces so that majority components of force vectors applied normal to the first and second bite surfaces are directed parallel to the wrench handle axis.