A wrench is a tool – the English call it a spanner – that is usually operated by hand, and is made for tightening or loosening bolts, nuts or anything that needs to turn. Solymon Merrick patented the first wrench in 1835.
The physics of a wrench are that the tool works as lever. There are notches at the mouth for gripping. The wrench is pulled at a right angle to the axes of the lever-action and the bolt or nut. Some wrenches have mouths that can be tightened to better fit various objects that need turning.
Charles Moncky invented the monkey wrench around 1858.
Robert Owen, Jr (1881 – 1956) invented the ratchet wrench. Owen received a patent on September 9, 1913. U. S. Patent number 1,072,980.
On September 13, 1870, a patent was granted to Daniel C. Stillson, a steamboat fireman, for a “wrench”. Stillson invented the pipe wrench – sometimes called the Stillson pipe wrench. Stillson, suggested to the heating and piping firm Walworth manufacture a design for a wrench that could be used for screwing pipes together. Previously, serrated blacksmith tongs had been used for that purpose. The owner, James Walworth told Stillson to make a prototype and “either twist off the pipe or break the wrench.” Stillson’s prototype twisted the pipe successfully. His design was then patented and Walworth manufactured the wrench. Stillson was paid about $80,000 in royalties during his lifetime.