Trailer coupling

The tow hook has a curved stirrup (50) over it which prevents the tow bar being fitted on to it until it is correctly inserted into the mounting (20) on the car. A spring loaded pin (64) whose end is supported by a vertical rod (42) in the car end (18) of the hook locks the stirrup in place until the rod engages with the mounting. It is then pushed down and the pin slides into a recess (70) in the side of the rod, allowing the stirrup to be swivelled aside and the tow bar fitted.