Abstract: A quick coupler for construction machines. An embodiment of the quick coupler comprises a housing with two opposing longitudinal walls, two opposing transverse walls, a top side, a bottom side, and a block cylinder inside the housing. The quick coupler may also comprise a locking device with a locking bolt and a drive device. The locking bolt protrudes from one of the two transverse walls in a locked position. The quick coupler may also comprise a first coupling element having a coupling end section and a second coupling element having a coupling end section hydraulically connected to one another, wherein the second coupling element is arranged on one of the two longitudinal walls of the housing.