Socket Wrench

A socket wrench, or socket spanner, is a tool that uses a closed socket format to turn fasteners such as nuts and bolts, in contrast to a traditional open-jawed wrench. The most common form is the ratcheting socket wrench, which incorporates a reversible ratcheting mechanism that lets the user turn a fastener with a back-and-forth pivoting motion rather than repositioning the tool after every turn; other ways of driving a socket include pneumatic impact wrenches, hydraulic torque wrenches and plain breaker bars. The ratcheting socket wrench with interchangeable sockets was invented by J. J. Richardson of Woodstock, Vermont, and patented on June 16, 1863, with the first known illustration of the tool appearing in the April 16, 1864 issue of Scientific American. Square drive heads were historically easier to manufacture by hand filing, but hexagonal designs became standard through the twentieth century as manufacturing improved and the hex shape performed better in confined spaces; a further refinement, the quick release mechanism common to modern ratchets, was invented and patented in 1964 by Peter M. Roberts.