got a call from a mate of mine today, who’s a traffic cop in thames valley,
he was attending an accident involving a hgv where the trailer has become detatched from the unit at a r/bout.thankfully no one injured & only damage was to unit & trailer.
after a bit of chat with him about it & giving him a bit of info,it turned out that the driver had neglected to put the dog clip on. 
what penalty would you expect to be dished out to by the rozzers for the offence,he (my mate) ended up giving the driver £60 & 3 points,which i don’t think is to bad for what/could have happened
I’d say he was a lucky boy, and he probably won’t forget the dog clip again…
But a dog clip does notvhold the trailer on just the lever in place the chances are the trailer was sat on top of the jaws and wouldve come off with or without the dog clip.
The dog clip doesn’t keep the trailer in position, it only stops the locking handle from moving from the closed position. Either the trailer wasn’t sitting in the jaws correctly from the get go or the locking mechanism failed due to lack of regular maintenance or component failure. The locking handle can appear to retract correctly and the dog clip put in but if the trailer pin isn’t sitting in the jaws properly nothing is going to stop the trailer from detaching at some point in the day.
Regards
Dave Penn;
It is a belt and braces thing, normally the dog clip will not go in if the arm is not fully retracted (connected properly) It is not failsafe but it is one of the checks you can do. A dog clip is a British thing and enforced by VOSA but in reality, most manufacturers don’t fit them.
In this case, it sounds like your man will just get done with no further investigation but in a lot of cases, trailer loss has been mechanical failure when the plastic wear ring collapses.
3 points and £60 fine - he should get some lottery tickets bought cus he is on to a winner 
If that had happened to me today it would have cost me my job without a doubt.
He obviously hadn’t picked the trailer up correctly in the first place (unless a 5th wheel malfunction) which I doubt.
Stobarts are really strict about these types of incidents and I know of at least 2 who have been dismissed for trailer runaways whilst coupling up.
1 was a runaway at Goole when a mechanic ended up injured when the unit hit his van!
2 tugs when under and double check the park brake is on - first things you are taught while training.
The DCPC will sort it though
Rick B:
The DCPC will sort it though
And in other news, the moon is made of cheese and pigs will fly. 
Coupling up and dog clips were covered extensively in a thread not so long ago!
anyone got any pictures to show me an example. I haven’t got a clue what your on about lol
mickyblue:
anyone got any pictures to show me an example. I haven’t got a clue what your on about lol
viewtopic.php?f=2&t=68787&hilit=wear+ring
viewtopic.php?f=2&t=51442&hilit=wear+ring
There are plenty on these two threads
cheers for that Wheel Nut, i now know what your all talking about lol
I can’t think of a modern tractor unit manufacturer whose trucks I haven’t had the pleasure of driving, and in my experience they all either had the L shaped spring loaded thingy on a wire or a hole in the plate with a dog slip on a chain attached to it. Also in my experience, the fifth wheel lever won’t go all the way ‘home’ to allow the dog clip to be attached/L shape thingy to drop down if the trailer isn’t properly connected in the jaws, so personally I call driver error on this one. Even if the jaws are worn where the trailer bangs backwards and forwards when you accelerate/brake, it still wouldn’t stop the dog clip/L lever from engaging.
i agree with Rob K even if the jaws are worn it will still close fully and lock and you should be able to put your dog clip in. on a side note another way to check you are coupled correctly is to look at the front of the 5th wheel and you will see what looks like a nut and bolt with usually a fat ish rubber washer between it and the 5th wheel. when you hook up to your trailer it shoots in and the nut should be tight up against your 5th wheel. if it ist then you have wear in the jaws and it can be adjusted to take the slack out