A safety coupling for the releasable connection of a nozzle to a duct system is disclosed. The safety coupling is adjustable between a coupled position, in which the coupling parts are coupled together to lock the connection of the nozzle to the duct system, and a decoupled position, in which the coupling parts are separable to allow release of the nozzle from the duct system. An actuating member is arranged to move the coupling member from the coupled position into the decoupled position when the coupling member is subjected to a disengagement force exceeding a predetermined limit value.