Now that you understand that inertia brakes mean the trailer can brake on its own, when the coupling head has dropped down into coupling housing on the trailer, how come you can still reverse?
Up until the 1990s, if you wanted to reverse, you had to get out of your vehicle and use a blocking device to prevent the coupling head from dropping into the housing. In forward motion, the system automatically disengaged.
Imagine the number of times you had to leave your vehicle to park your caravan on the campsite!
Well, holidaymakers had time on their hands and at worst they could unhook the caravan and the neighbours would come and help push it. However, this could be dangerous if manoeuvring was required at a road junction!
Equipment manufacturers have therefore invented a system so that when the drum rotates in reverse, an automatic brake release system makes reversing possible.
Did you know that?