Adjustable Wrench (1891) | Johansson devise a tool for every nut

 "Man is a tool using animal....... Without tools he is nothing, with tools he is all." Thomas Carlyle, historian 

Johann Petter Johansson (1853-1943) was one of Sweden's most prolific inventors. He amassed an impressive 118 patents over his lifetime, including one for tongs to enable people to put sugar cleanly into their tea. However, undoubtedly Johansson's greatest contribution to manufacturing and engineering was his adjustable wrench. 

An example of one of the earliest adjustable wrenches, from 1892

When Johansson opened his first workshop in Enkoping, Sweden, in 1886, there were no standard sizes or gauges for nuts, bolts and screws nor nor for the tools that manipulated them. Johansson became literally overloaded when he went about his business because his handcart had to accommodate ever increasing numbers of wrenches to fit his various jobs. He practically had to make a new size of wrench for each task as machines and their components were built to their own bespoke specifications. 

Johansson decide to make a single tool that would have some of the dexterity of a human hand. "Iron Hand" his tool of 1888 became what is now known as the pipe wrench. While eventually becoming indispensable, the pipe wrench would often ruin rusty or stuck bolts, so in 1891 he refined the design to produce the adjustable wrench.

Basically the same shape as a normal wrench, Johansson's device had an integral screw thread that, when turned, would adjust the distance between the opposing "jaws" of the wrench's working end. This meant that the tool could be offered up to the head of any nut and then adjusted to get a perfect fit--eliminating the inventor's need to carry a whole bunch of different wrenches around with him.