Tow bar

The trailer coupling (1) has a housing (2) in which a lockbolt (9) is slidably mounted, an operating lever (3), a pivotally mounted spherical shell (13) and a pivotally mounted safety lever (26) that cooperates to the lockbolt. The spherical shell is free and independent of the safety lever and the lockbolt is pivotally mounted in the opening position of the trailer coupling. The spherical shell has releasable abutment on the lockbolt at the rear end of curved portion contour.