Adjustable spanner

There are many forms of the adjustable spanner or wrench, from the taper locking spanners which needed a hammer to set the moveable jaw to the size of the nut, to the modern screw adjusted spanner.

Even digital spanners have been made which use sheets or feelers to set the size, some types uses a serrated edge to lock the moveable jaw to size.

There is also a class of adjustable that automatically adjusts to the nut size.

The adjustable spanner was invented by Edwin Beard Budding (1795-1846), who also invented the lawnmower.

A later form of adjustable was invented in Sweden by J. P Johansson in 1892.

Ref 1: http://www.bbc.co.uk/history/historic_figures/budding_edwin_beard.shtml

More information on adjustable spanners can be found at: http://www.adjustable.archivist.info