Confidence in a tow hitch

[nickk]

Lifting my trailer,got carried away how high,anyway was impressed on the pull out resistance.

 

[brightspark]

they will take some stick I was driving down road with my trailer and heard a great crunch looked in the mirror and both trailer wheels were up in the air about a foot . id drove over a speed hump and the jockey wheel dug in and flipped the trailer up

 

[sako243]

I'd be curious to see what would have happened if you didn't have that inch and a half of fork beyond the ball. I suspect it might have popped then.

 

[nickk]

I'd be curious to see what would have happened if you didn't have that inch and a half of fork beyond the ball. I suspect it might have popped then.

Let me know the results,lol.

 

[4String.]

After all these years I'm still amazed that an artic truck is connected to well over 30 tons of load and trailer by a 2" diameter pin.

And similarly that a 30 ton shipping container is held to to a trailer by 4 skinny little twistlocks.

 

[Bill Edwards]

Yet by contrast sometimes you see the proper equipment fail, and great big heavy pins etc bend or break unexpectedly. Works both ways...

 

[skotl]

they will take some stick I was driving down road with my trailer and heard a great crunch looked in the mirror and both trailer wheels were up in the air about a foot . id drove over a speed hump and the jockey wheel dug in and flipped the trailer up

Luckily, I have an early warning system 10ft out my drive in the shape of a speedbump. When I hear a big CLONK driving over that, that's the reminder that I haven't put the jockeywheel up

 

[brightspark]

just think of all the strain put on the pins on a excavator bucket

 

[earthman]

After all these years I'm still amazed that an artic truck is connected to well over 30 tons of load and trailer by a 2" diameter pin.

And similarly that a 30 ton shipping container is held to to a trailer by 4 skinny little twistlocks.

Yes, I've often thought that too.

 

[Barking Mat]

I spent an hour welding a ring tow fitting to a length of 60 x60 x 4 square bar Yesterday, not bar , square tube? Whatever. Rated at 14 ton. Not had a problème so far.

Photos tomorrow.

 

[4String.]

Luckily, I have an early warning system 10ft out my drive in the shape of a speedbump. When I hear a big CLONK driving over that, that's the reminder that I haven't put the jockeywheel up

Slightly off-topic, I had a splendid week's scuba diving out of Kinlochbervie recently.

At the end of the week we were joined by a couple that we all assumed were mother and son, (she was probably mid 50's and he looked mid/late 20's), but it turned out he was her FOURTH husband . Anyhow, towing their wobble box along the single track "B" road from Lairg to Laxford Bridge she'd had to move over to get out of the way of an oncoming fish artic. I had to smile when she told me about this huge lorry covered in spotlights that "forced her off the road".... When she moved over she heard a loud clunk but didn't think any more about it, which turned out to be the motor mover engaging with the o/s tyre.

By the time she arrived at Kinlochbervie, the roller had taken all the tread off and had got down to the wire .

 

[bricol]

After all these years I'm still amazed that an artic truck is connected to well over 30 tons of load and trailer by a 2" diameter pin.

And similarly that a 30 ton shipping container is held to to a trailer by 4 skinny little twistlocks.

I thought it was a 4 tonne trailer held quite well to a 30 tonne container . . .

 

[earthman]

I thought it was a 4 tonne trailer held quite well to a 30 tonne container . . .

I suppose that 99% of the time it's just a case of 30 tons pressing down on a trailer, those pins ain't really doing much I'd guess.

I'd like to know how much testing of such like did they do in other extreme positions etc.
When articulated rigs do end up on their sides, anyone know of the cab becoming detached from the trailer?
I would have thought that pin would just snap but I've never seen that on the recovery TV programmes for example.

 

[cheb]

To me it's less about the pin and more about the locking mechanism for the pin. Just like a car door catch, but bigger.

That's something to ponder on next time you're behind an artic.

 

[4String.]

I suppose that 99% of the time it's just a case of 30 tons pressing down on a trailer, those pins ain't really doing much I'd guess.

I'd like to know how much testing of such like did they do in other extreme positions etc.
When articulated rigs do end up on their sides, anyone know of the cab becoming detached from the trailer?
I would have thought that pin would just snap but I've never seen that on the recovery TV programmes for example.

I admit to having a thing for watching programmes such as Highway through Hell and Ice Road Rescue, and whenever they go to rescue an artic that's ended up on its side, it invariably stays coupled.

Even the B trains beloved of the Scandinavian folk that have 2 trailers and run at around 60 ton gross don't seem to fail. And the heavy rescue boys don't mess with them either. Hook a couple of lines on and winch them back onto their wheels, hook them up to the wrecker and away they go!,

 

[Gritineye]

The important factor on an artic pin isn't the weight of the loaded trailer, it's the grip of the tires on the road that limits the strain on the pin.

 

[jimbo84]

And when the airlines fail and the brakes lock on the trailer it stays connected, a fully loaded trailer suddenly applying full brakes with a 10ton tractor unit and often upwards of 400bhp pulling in the opposite direction must be some force.

 

[skotl]

Cos I'm bored I googled "artic king pin" to find out a little more about these. First prize for best response to a king pin question can be viewed here:

http://www.trucknetuk.com/phpBB/viewtopic.php?f=2&t=85284

Question: "King pins: Does anyone on here know what the usual "sympton" is when these go?"
Response: "Usually the trailer doesn't follow you"​

 

[4String.]

And when the airlines fail and the brakes lock on the trailer it stays connected, a fully loaded trailer suddenly applying full brakes with a 10ton tractor unit and often upwards of 400bhp pulling in the opposite direction must be some force.

Not an artic but a wagon and drag, some years back I had an airline burst on the drag trailer as I was heading over the A66.

The entire rig came to a shuddering halt in under 4 seconds , which didn't even give me time to default to my usual "Oh FFS!!!" It turned out to have melted through the pipe because the wagon had never been fitted with an exhaust tail pipe so the hot gasses were hitting the main chassis member and burnt through the plastic pipe . It did it again later in the journey just as I was powering up Beatock on the A74M, and I didn't have enough time to get onto the hard shoulder. I ended up sat in a Police car parked on the hard shoulder with all its lights ablaze and half of the wagon in lane 1 until the recovery boys did their thing.

Came close to a severe telling-off by the female Inspector who was driving and just happened to be out for a jolly when I called it in on 999. She didn't appreciate my, err, weird sense of humour, especially when I asked if I could have a go with her Tazer .

 

[bricol]

Promotional videos of trucks with ABS doing an emergency stop are rather impressive - something that size stopping that quick! Don't think I'd like to be checking anything on the brakes immediately after though, the rate of conversion of kinetic energy . . .