Adjustable spanner

An adjustable wrench (US) or adjustable spanner (UK) is a wrench with a "jaw" of adjustable width, allowing it to be used with different sizes of fastener head (nut, bolt, etc.) rather than just one fastener, as with a conventional fixed spanner.

In many European as well as Middle Eastern countries (e.g. France, Germany, Portugal, Spain, Italy, Syria, Lebanon, Turkey, etc.) the adjustable wrench is called an "English key" as it was first invented in 1842 by the English engineer Richard Clyburn. Another English engineer, Edwin Beard Budding, is also credited with the invention. Improvements followed: on 22 September 1885 Enoch Harris received US patent 326868 for his spanner that permitted both the jaw width and the angle of the handles to be adjusted and locked. Other countries, like Denmark, Poland and Israel, refer to it as a "Swedish key" as its invention has been attributed to the Swedish inventor Johan Petter Johansson, who in 1892 received a patent for an improved design of the adjustable spanner that is still used today. Johansson's spanner was a further development of Clyburn's original "screw spanner". In some countries (e.g. Czech Republic, Egypt, Greece, Hungary, Serbia, Iran, Slovakia, Slovenia, Poland, Croatia, Romania, Bulgaria) it is called "French key" (in Poland, "Swedish" or "French" key depending on type). In Canada and the United States, the tool is known as a Crescent wrench or an adjustable wrench.

There are many forms of adjustable spanners, from the taper locking spanners which needed a hammer to set the movable jaw to the size of the nut, to the modern screw adjusted spanner. Some adjustable spanners automatically adjust to the size of the nut. Simpler models use a serrated edge to lock the movable jaw to size, while more sophisticated versions are digital types that use sheets or feelers to set the size.

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Wikipedia