Adjustable spanner

An adjustable spanner, shifting spanner, shifter, crescent wrench or adjustable-angle head wrench (American English) is a tool which can be used to loosen or tighten a nut or bolt. It has a "jaw" (the part into which the nut or bolt goes) which is of adjustable size, which allows for different size nuts and bolts to be handled by the same spanner. Compare this to the ordinary spanner which has a fixed size. General info: Adjustable wrench Size: 6. ... For other uses, see Tool (disambiguation). ... A nut is a type of hardware fastener with a threaded hole. ... Screws come in a variety of shapes and sizes for different purposes. ... A wrench or spanner is a tool used to turn bolts, nuts or other hard-to-turn items. ...

There are many forms adjustable spanners, 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.

There is a class of adjustables that automatically adjust to the size of the nut. The most modern are digital types that use sheets or feelers to set the size, and other simpler models that use a serrated edge to lock the moveable jaw to size.

It is uncertain who invented the adjustable spanner. Some early spanners were invented by Edwin Beard Budding (1795-1846) using a screw to replace the wedge that fixed the jaw of a known type of adjustable spanner, and Johan Petter Johansson of Sweden in 1892 using a screw to adjust and fix the jaw.^[1] In addition a type called a monkey wrench is thought to have been patented by one Charles Moncky. In music, an invention is a short composition with two or three part counterpoint. ... Edwin Beard Budding (1795-1846)an engineer from Stroud, Gloucestershire, England was the English inventor of the lawnmower (1830) and adjustable spanner. ... Johan Petter Johansson (December 12, 1853–August 25, 1943), sometimes known as JP, was a Swedish inventor and industrialist. ... 1892 (MDCCCXCII) was a leap year starting on Friday (see link for calendar). ... Monkey Wrench Modern version The monkey wrench is an adjustable wrench not much used today. ...

Proper use

Torque applied via a crescent wrench

This tool is often misused, causing excess wear or distortion. When the type illustrated is used for heavy loads such as to break loose a nut or bolt, or for final tightening, the movable jaw should always lead the direction of rotation. Failure to do so will cause the movable jaw to become bent and/or loose. (In the illustration the wrench is set up to tighten a right hand thread, using a clockwise motion) Image File history File links Fysik_vridmoment. ... It has been suggested that this article or section be merged with Moment (physics). ... A nut is a type of hardware fastener with a threaded hole. ... Screws come in a variety of shapes and sizes for different purposes. ...

Another school of thought claims that the spanner should always be used with the fixed jaw leading the direction of rotation. The force on each jaw is always the same (equal and opposite forces) regardless of the direction of rotation. However, if the fixed jaw is leading, then the force will be applied to the movable jaw at its base, which will minimise the bending stress on it.

The movable jaw should be snugly adjusted to the nut or bolt head in order to prevent rounding. This type of wrench should never be used on a rounded off nut, as this can overload the movable jaw. Nor should the wrench be used "end on" in cramped quarters, where a socket wrench is more appropriate.
A socket wrench is a type of wrench, or tightening tool, that uses separate, removable sockets to fit many different sizes of nuts. ...

Generalized trademark

In the US, the term crescent wrench is often used by the general public as a generic term to indicate any adjustable spanner. It is however a brand name owned by the company Cooper Hand Tools ^[2]. In some parts of Europe they are often called a bahco, which is a generalized trademark as well.:^[1] United States may refer to: Places: United States of America SS United States, the fastest ocean liner ever built. ... A genericized trademark, generic trade mark, generic descriptor, or proprietary eponym, is a trademark or brand name which has become the colloquial description for a particular class of product or service. ... This article is 150 kilobytes or more in size. ...

References

1. ^ ^{a b} Swedish Bahco leaflet about the development history of adjustable spanners (including photo’s)
2. ^ Homepage of Cooper Hand Tools

External links

• More information on adjustable spanners