Wedge (mechanics)

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Axe with a wide angle wedge for splitting logs

The downwards force on the wedge produces a horizontal force in the object

A wedge is a simple machine, technically a portable double inclined plane, used to separate two objects, or portions of objects, through the application of force, perpendicular to the inclined surfaces, developed by conversion of force applied to the wide end. The mechanical advantage of a wedge depends on the ratio of its length to its thickness. Where a short wedge with a wide angle does the job faster, it requires more force than a long wedge with a smaller angle.

Wedges can also be used to lock engine parts in place, e.g. see poppet valve.

The origin of the wedge is unknown, because it has been in use as early as the stone age.

Examples include axes, nails and teeth . Knives and chisels can sometimes be used as wedges, however, they are more fundamentally cutting implements. In some sense, door stop (door wedge) can also be regarded as wedge technically, but its main function is to provide a friction between the door and the ground rather than separating materials.