“Yeah sure, I learnt all about coupling when I did my test, but after watching the way the old hands do it. Why should I bother.” Partially true, but the very fact that they are old hands means that they have been coupling trailers on a regular basis for many years and have developed a feel not only of the vehicle, but also of their surroundings.
Even approaching the trailer, they have assessed the height of the pin, the gradient, what is to the rear, and the likelihood of anyone walking behind the trailer at a crucial time.
Nowadays we would call this a risk assessment. Formerley we would have referred to it as wisdom borne of experience.
SO JUST WHAT CAN GO WRONG?
The first consideration is the height of the trailer. It may have been parked at the correct height, but if it is on a bay, then is there is a chance that a Forkie has been running in and out of it. The trailer suspension tries to compensate for the changes in weight, the air supply becomes exhausted, the rear of the trailer settles, and the front goes up.
Try and couple up to that and there is a chance that the vehicle will pass underneath the pin, and as you push further back, the lamp lenses smash on the trailer legs, or even worse, particularly with a reefer and a sleeper cab, the fridge impales itself into the rear of the your vehicle causing damage to both.
At the other end of the scale is the trailer that is too low. Not all units are fitted with ramps leading up to the fifth wheel coupling. Finding this out when the front of the trailer has crushed your mudguards into the drive axle tyres, is a little too late.
So we have established that the height of the trailer is in the right proportion for our vehicle. Check the trailer brake?
“Nah, it wont move 'till I put the red line on. They never do.” Unless, of course, someone has opened the Shunt valve.
It’s bad enough taking down an old wall or a stretch of fencing, but what about the girl from the office that has nipped behind the trailer for a quick cigarette, out of sight of the Boss and the yard cameras. We all know smoking is bad for the health, but being crushed by a trailer is invariably terminal.
So now it’s time to reverse under the trailer. If you have air suspension on the trailer, lower it fully before going backwards. This reduces the possibility of damage to the mudguards and minimizes scraping grease off the coupling plate onto the leading edge of the trailer and thence onto the airlines.
“…he connected the red line and as I watched, both the unit and trailer started to roll towards a fence. He jumped clear as it gathered speed…”
If the trailer is fitted with a deep-set pin, and particularly if it is a reefer with a front mounted fridge, then this is the time you may choose to connect the airlines.
Leave the suspension down for now — not so far to climb up onto the catwalk and therefore, not so far to fall. If the vehicle is on a gradient and you have forgotten to set the parking brake, you will quickly notice and be able to rectify the matter. If you had lifted the suspension into contact with the trailer then the friction would most likely have held the unit UNTIL, and this again stresses the importance of checking the trailer brake, the red line was connected, when both would be capable of rolling freely with YOU being carried as a passenger.
Back at the driving seat, lift the suspension and WATCH for the trailer to lift. By lifting the trailer legs clear of the ground your are eliminating stresses created when the coupling is not accurately aligned with the pin, and also created when pushing backwards and tugging forward. Be aware that on a side slope there is a possibility of the trailer slipping sideways and it may be advisable to ensure that the pin is located within the V of the coupling before raising the suspension.
“…a good friend of mine hitched up to a 44 fridge in the normal manner. He then squeezed himself in between tractor / trailer to put on the airlines etc. He puts on his red line first and you already know when you do this sometimes the trailer can lurch forward a couple of mill, and there he was trapped (not hurt) but well stuck never the less…”
Push backwards until you hear the coupling engage. Select a low forward gear and tug forward twice. Fit the clip, or if the unit is fitted with a spring-loaded wedge, check that it has engaged properly. Fitting the clip is a final check of whether the coupling is fully engaged. If the clip don’t fit. It isn’t connected properly.
“…Doing it the same way every time also helps if you are distracted at anytime because all you do is go back to the start & check everything in the same order as you normally would.”
Connect the Suzy’s (if not already done). Wind up the legs and release the trailer brake. Don’t be too quick to walk off after releasing the trailer brake. If you have neglected to apply the parking brake and the whole lot starts moving, resist the temptation to run round to the cab.
Simply re-apply the trailer brake and wait. On some trailers the brakes will apply immediately, on others you may have to wait a few seconds. Either way, it is preferable to risk ending up under the wheels of the vehicle.
Return the suspension to normal ride height, fit number plate, and check lights, etc.
Develop a system that suits YOU for your sector of the industry and stick to it.
Uncoupling is largely a reversal of the whole procedure. If you have a mixture of surfaces and the trailer is to be loaded/unloaded by a Forkie, make sure the trailer overhangs the concrete area; otherwise you will not be popular.
Whether the trailer is uncoupled at normal ride height or ‘low’ is largely a matter of company policy, but rarely would it be normal practice for a trailer to be uncoupled with the drive axle suspension set high.
A mnemonic to remember is BLACK
Apply trailer BRAKE.
Lower LEGS.
Disconnect AIR and electrical lines.
Look and CHECK that everything has been done.
Release KINGPIN and pull slowly forward.
Remember:Lighthearted ribbing from your colleagues is less damaging to your income stream than a written warning from your employer.
Points to ALWAYS consider, particularly in isolated or quiet locations.
If I get injured, is there anyone nearby who can help me, and would they be able to hear me above the noise of the engine?
Is my phone in a pocket that I can reach easily, and do I know the name of the yard/road where I am?
Should I phone my office first, and then if they don’t hear back from me, they can contact someone to check on me.
Always be prepared to check, and check again…