Coupler
# Coupler

Coupler may refer to:

## Engineering

### Mechanical

* Railway coupler, a mechanism for connecting rolling stock on a train
   * Janney coupler
   * SA3 coupler
   * Scharfenberg coupler for multiple unit passenger cars
* Quick coupler, used in construction machines to allow the rapid change of buckets
* Coupling, a device used to connect two shafts together at their ends for the purpose of transmitting power
   * Universal coupling, a joint or coupling in a rigid rod that allows the rod to 'bend' in any direction

### Electronics

* Acoustic coupler, for coupling electrical signals by acoustical means
* Directional coupler, a passive device used in radio technology
* Antenna coupler, a device connected between a radio transmitter or receiver and its antenna
* Output coupler, a partially reflective mirror used in lasers

## Other uses

* Coupler (piping), also called a (joist) short length of pipe with two female threads
* Coupler, a device used on a pipe organ or harpsichord to allow a player to play multiple divisions at once, by means of "coupling" a division to another at either sub, super, or octave pitches
* Coupler, a tap valve, for controlling the release of beer out of a keg
* Coupler, the floating link in a four-bar linkage
* Hydrant coupler, for aircraft fueling equipment
