US Patent 9061401 Hex wrench having greater strength

A hex wrench includes a handle with a first twist portion having a substantially helical profile through an entire length thereof, a head with a second twist portion having a substantially helical profile through an entire length thereof, and a curved transition portion connected between the handle and the head. A first mounting portion which is a regular hexagonal prism and non-twisted extends integrally from the handle, and a second mounting portion which is a regular hexagonal prism and non-twisted extends integrally from the head. As such, the hex wrench has greater strength and stiffness without reducing its malleability so as to prevent the hex wrench from being cracked or broken due to an excessive applying force.