Adjustable spanner
A crescent wrench is a box spanner to loosen and tighten screw connections.
By turning a knurled screw the distance between the jaws can be adjusted continuously. Thus, it can be used for different sized four-or even-numbered polygons (6, 8, 10, ..), eg for square nuts or bolts are used for various systems of units (metric and imperial) and after proprietary company standards as.
Invented and patented ( May 11, 1892 the patent number SE4066 ) has left him, the Swede Johan Petter Johansson in his workshop Enköpings Mekaniska in Enköping, which he founded after he had in 1886 invented the water pump pliers. B. A. Hjört & Co. ( Bahco ) produced and then marketed the tool from 1892 to today in the whole world.
Designation
Colloquial errors
English is the slang term for all types of adjustable wrenches, especially for those with only one side present mouth. Strictly speaking the Englishman is an adjustable wrench in which the adjustment of the wrench size is via a threaded spindle in the tool shank. For most commonly used today adjustable wrenches, however, the adjustment via a worm gear in the key head is done ( see figure). The correct term for such tools is adjustable wrench, also adjusting key. Finally, there are so-called Frenchman. These changing the key length of the interaction between a right and a left hand thread spindle by rotating the tool shank is done. Due to the different pitch of the threaded small adjustment paths for each tool shaft rotation are possible. In contrast to the British and the French one adjustable wrench double open is present.
Other tool types
Since the mouth is only present on one side at the British and the adjustable spanner, this offer compared to the Frenchmen in confined premises benefits. Regarding the durability and quality over the years is an open-end wrench or ring spanner superior to the English, because there are no moving parts. In return, adjustable wrenches for ( Hex ) can use screws, for which no suitable key is tangible.
Thus, the Englishman is no competition to open-end or box wrench is but a completion of the Network or from the tool box.
The origin of the name of Englishman is believed that in workshops on this tool for cost reasons for the in Continental Europe less widely inch (speak English - see also Joseph Whitworth ) was resorted bolts and nuts, if only metric open-end or box wrench are available.
In English-speaking countries is called the crescent wrench as "adjustable - wrench" or "adjustable - spanner ". The first adjustable tensioner was already invented in 1842 by Richard Clyburn, this had a slightly curved S-shape. Since 1990, the retired teacher Ian Harrison from England developed in the further development of the adjustable wrench. In 2006 he invented Milli -grip. This tool was honored at the British Inventors' Fair Gold Medal. Unlike the typical crescent wrench to Milli -grip simply presses together to the required size. By locking the forceps jaw snaps then any one in millimeter increments. By pressing a button, the collet is released. This you can switch within seconds between a 8 mm and a 32 mm screw head. An unintentional adjustment of the key size is no longer possible.
Handling
Improper handling of the adjustable wrench often leads to abnormal wear or deformation of the tool. If for loosening and tightening screws or nuts a crescent wrench as shown in the figure used, it should be noted that the moving part of the mouth or the fork in the direction of rotation to be executed shows. Failure to comply with the movable side of the fork or the adjustment mechanism can be bent and consequently have excessive play, the tool is useless.
Furthermore, make sure to choose the length of the adjustable fork as closely as possible to the rotating screw or nut. If the fork width chosen not tight enough, this can lead to sliding off the polygon. For one, the bolt or nut can be turned around. The corners are worn by plastic deformation, and a loosening or tightening will eventually impossible. By slipping when high body forces the risk of injury is high.
- Hand tools