Johnson bar (vehicle)
From Wikipedia, the free encyclopedia
- This article is about a hand lever used in various vehicles, for other uses of the term, see Johnson bar (disambiguation).
A Johnson bar is a hand lever with several distinct positions and a positive clutch to hold the lever in the selected position. The positive clutch is typically activated with a spring-loaded squeeze handle on the lever so that only one hand is needed to release the clutch, move the lever, then reengage the clutch.
Many steam locomotives have valvetrain controls which are set using a Johnson bar as referenced in Fred Eaglesmith's Back There: Hey Porter, tell that engineer, tell him this train's too slow. Tell him to let go that Johnson bar. I got places I got to go.
Many trucks and buses use a hand brake which is controlled with a Johnson bar. These are sometimes called "Johnson bar brakes".
Truck drivers used to call lever controls on air-operated trailer brakes "Johnson bars".
On Caterpillar Tractors the forward / reverse lever is also called a Johnson bar.
Some light General Aviation Aircraft use Johnson Bars to mechanical actuate wheel breaks and some older aircraft have Johnson Bar actuated landing gears systems.
