Johnson bar (vehicle)
Johnson bar is the term for several different hand-operated levers used in vehicles. Their distinguishing feature is a positive latch, typically spring-loaded, to hold the lever in a selected position, capable of being operated with one hand. Some Johnson bars have a fully ratcheting mechanism, some just a series of detents, and others yet simply engaged and disengaged positions.
A common example is the Johnson bar-controlled parking brake found on many trucks and buses.
Johnson bar is also the North American term for a steam engine's reversing lever, used to control the valve gear.
The forward/reverse lever on Caterpillar tractors is also called a Johnson bar.
Some light general aviation aircraft —use Johnson bars to actuate flaps and wheel brakes. The Cessna 162 Skycatcher uses a Johnson bar for flap operation. A small number of older aircraft also have landing gear actuated by Johnson bars.
The Boeing 707/720 aircraft had a Johnson bar for manually extending the nose landing gear, in case the normal gear extension failed.