Hooks in Safety Chains

yobarr · Guru

Hooks in Safety Chains

Possum3 · Guru

A typical 10mm "Clevis Hook" has approximately a 5 tonne safety rating which would mean somewhere between 15 tonne and 20 tonne breaking strain.

The pictured hook would not have been distorted by a caravan breakaway - more likely pulling stumps or similar abuse.

It of course could be an Aluminium Clevis Hook (unrated) painted to deceive.

The "Hammerlock" fittings shown are totally legal chain attachments (in Australia).

-- Edited by Possum3 on Saturday 8th of April 2023 11:40:57 AM

Craig1 · Guru

One of the suppliers of the Clevis hooks said to me they would not use them on a towing situation as the spring retainer clip could not be guaranteed to stay shut when in motion, thus allowing chain to bounce off.

Long Weekend · Guru

I wonder if the fact that the tug is on the back of a trailer has any bearing on what happened to the hooks?

Murray

EJP · Senior Member

A few things come to note here.
1. The vehicle is on a trailer
2. The hook on the other side is missing
3. The bottom section of the hammerlock is missing and the pin appears to be broken.
There is a lot more to this than meets the eye.

Warren-Pat_01 · Guru

Hi yobarr,
I was stunned recently that Autobarn have these devices on their Towing Equipment section of their stores.

Perhaps they should add the same comment that they have on their high powered globe upgrades for a car's headlights "Does not meet ADRs for on road conditions".

BarneyBDB · Senior Member

In what way does it not meet ADR's? Preferably fact, not opinion.

Cuppa · Guru

https://shop.ch-s.com.au/products/vehicle-safety-chain-hook-kit (product)

The following from questions on their web site.

Are these legal?

1 month ago

>> replied:

AUSTLIFT has consulted with various divisions that established the current standards; the following information and definitions were gathered by AUSTLIFT from Australian Standards AS4177.4, AS3776 & ADR6202:
Divisions Contacted:
1. Australian Government Department of Infrastructure and Regional Development.
2. Commonwealth Department of Transport and Regional Services
3. Recreational Vehicle Manufacturers Association of Australia
4. Roads and Traffic Authority of New South Wales
5. Caravan Industry Australia.
Our product's chain size is based on the ATM (Aggregate Trailer Mass) according to AS 4177.4 section 6, up to 3.5t. A 13mm or 16mm G80 chain is required for loads greater than that. Our labels have been adjusted to reflect the two standards involved. The hook conforms to AS Standard 3776:2015, and the coupler conforms to vehicle standard AS4177.4.

Here are the kit codes and their corresponding chain sizes and load capacities:

6mm Kit (Code: 103506): Suitable for 8mm & 10mm Trailer Chain (up to ATM 1600KG)

8mm Kit (Code: 103508): Suitable for 10mm & 13mm Trailer Chain (up to ATM 2500KG)

10mm Kit (Code: 103510): Suitable for 13mm Trailer Chain (up to ATM 3500KG)

It was explained to AUSTLIFT that the connectors (couplers) that connect the hook to the vehicle fall under the ADR6202 because once connected, it becomes a permanent assembly, where a shackle is a temporary connection point between the trailer and the vehicle as it can be removed.
The breaking strengths, WLL (Working Load Limit), and safety factors for our g80 hooks are as follows:
6mm G80 hook: WLL of 1.1t, safety factor of 4.4t, breaking force of 4,480kg (chain breaking strength 8mm/2,406.53kg)

8mm G80 hook: WLL of 2.0t, safety factor of 8.0t, breaking force of 8,000kg (chain breaking strength 8mm/2,406.53kg, 10mm/3,762.75kg, and 13mm/5,261.73kg)

10mm G80 hook: WLL of 3.2t, a safety factor of 12.8t, breaking force of 12,800kg (chain breaking strength 13mm/5,261.73kg)

Our G80 hooks and couplers have greater breaking strength than the chain and a safety factor of 4 to 1, allowing them to be used across different chain sizes.

BarneyBDB · Senior Member

Thanks Cuppa, that agrees with my findings from other sources. As the holder of a Dogman's licence I am aware of lifting equipment ratings and did my research before fitting those hooks to my own vehicle a couple of years ago.

dorian · Guru

Cuppa wrote:
The breaking strengths, WLL (Working Load Limit), and safety factors for our g80 hooks are as follows:
6mm G80 hook: WLL of 1.1t, safety factor of 4.4t, breaking force of 4,480kg (chain breaking strength 8mm/2,406.53kg)
8mm G80 hook: WLL of 2.0t, safety factor of 8.0t, breaking force of 8,000kg (chain breaking strength 8mm/2,406.53kg, 10mm/3,762.75kg, and 13mm/5,261.73kg)
10mm G80 hook: WLL of 3.2t, a safety factor of 12.8t, breaking force of 12,800kg (chain breaking strength 13mm/5,261.73kg)

The precision is silly, so I tried to convert them to other units to see where the numbers came from. However, I haven't been able to make sense of them.

Cuppa · Guru

dorian wrote:
Cuppa wrote:
The breaking strengths, WLL (Working Load Limit), and safety factors for our g80 hooks are as follows:
6mm G80 hook: WLL of 1.1t, safety factor of 4.4t, breaking force of 4,480kg (chain breaking strength 8mm/2,406.53kg)
8mm G80 hook: WLL of 2.0t, safety factor of 8.0t, breaking force of 8,000kg (chain breaking strength 8mm/2,406.53kg, 10mm/3,762.75kg, and 13mm/5,261.73kg)
10mm G80 hook: WLL of 3.2t, a safety factor of 12.8t, breaking force of 12,800kg (chain breaking strength 13mm/5,261.73kg)
The precision is silly, so I tried to convert them to other units to see where the numbers came from. However, I haven't been able to make sense of them.

I didn't try, I only posted what the people who sell them use to justify doing so so. Personally I'm quite happy to continue using shackles.

Brenda and Alan · Guru

Dorian I just tried US tons and the figure 5261.73 equates to 5.8 us tons. But I have to agree that quoting ratings to such finesse is ridiculous. 5.2 Tonnes would have been adequate for the chart. The other two figures do not convert to simple numbers however, so maybe someone stuffed up the conversions.

Alan

ps It was my understanding that the rough relation of WWL and breaking strain was taken to be 6:1

-- Edited by Brenda and Alan on Tuesday 11th of April 2023 09:04:43 AM

Long Weekend · Guru

Sort of in the same way of involving safety chains.

How many caravan breakaways have been saved by safety chains, and how many caravans have been destroyed by breaking free; ie, the safety chains not held by the D shackle or other hook ups?

While I don't recall any myself, that doesn't mean that hasn't happened. All of the accidents I read about are because of sway, jack knifing, bad roads, hitting roadside objects and so on.

Back in the old days couplings were 'locked' down on the tow ball by turning a wheeled knob. Often the knob wasn't turned down enough or simply forgotten altogether, allowing the tow bar to jump off the tow ball.

Since those days the couplings are spring loaded and when released down it locks securely. Unless releasing the handle is overlooked - and yes, I have done that! Fortunately, I remembered after driving some 20kms when I couldn't remember whether or not I had actually released the catch.

Perhaps the next step would be to have pintle hooks that lock securely, meaning that safety chains would no longer be required.

Murray

Edit: An observation of how securely the modern coupling locks down during accidents the coupling stays on the tow ball through jack knifing and rolling, generally taking the tow vehicle with it!

-- Edited by Long Weekend on Tuesday 11th of April 2023 02:46:38 PM

yobarr · Guru

Edit: An observation of how securely the modern coupling locks down during accidents the coupling stays on the tow ball through jack knifing and rolling, generally taking the tow vehicle with it!

DO35 sorts that!

yobarr · Guru

.

Perhaps the next step would be to have pintle hooks that lock securely, meaning that safety chains would no longer be required.

We tow a 12 ton PIG trailer with pintle-hook equipped 10 ton tipper, and safety chains MUST be used. Cheers

Long Weekend · Guru

Thanks Yobar. I'm in error.

Murray

Long Weekend · Guru

Thanks Yobar. I'm in error.

Not sure what I'm looking at in the photo you posted. It looks like it is on it's side, thought it was the tow vehicle but safety chains would be on the trailer. Anyway, whatever it looks mangled!

Murray

yobarr · Guru

Long Weekend wrote:
Thanks Yobar. I'm in error.

Not sure what I'm looking at in the photo you posted. It looks like it is on it's side, thought it was the tow vehicle but safety chains would be on the trailer. Anyway, whatever it looks mangled!

Murray

Hi Murray. It is indeed a caravan on its side, but you'll note that the DO35 has pivoted, allowing the car to stay on its wheels. Cheers

stephenboyd · Newbie

Hey everyone, this company seems to have their trailer chain clevis hooks approved for use in Australia.

https://shop.ch-s.com.au/products/vehicle-safety-chain-hook-kit

they have component type approvals which lists them as "full compliance" with ADR62/02.

https://shop.ch-s.com.au/cdn/shop/files/CTA_Approvals.pdf

Cuppa · Guru

stephenboyd wrote:
Hey everyone, this company seems to have their trailer chain clevis hooks approved for use in Australia.

https://shop.ch-s.com.au/products/vehicle-safety-chain-hook-kit

they have component type approvals which lists them as "full compliance" with ADR62/02.

https://shop.ch-s.com.au/cdn/shop/files/CTA_Approvals.pdf

I was sceptical, but they do seem to have the appropriate approval, unlike most. In fact they claim that their product is the only product of this type to have that correct approval for use with towing chains. .

I will continue to give the yellow hook brigade a wde berth when I see them on the road.

Greg 1 · Guru

Can't say that I am a fan. Will stick with my rated shackles me thinks.

stephenboyd · Newbie

Ive looked into it and I certainly does appear that they are the only ones approved. I did a through search on the CTA registry and they are the only ones

Gundog · Guru

I think it's a quick and easy way to hook up, looks ok but I dont want a pair of Yellow or Red danglie thinks hanging off my towbar they look crap.

Then I saw alternative way of using the hooks put oversize hammerlock on the towbar and attach the the hooks to the safety chain, spray them with silver or black paint to get rid of the ugly yellow.

shopping?q=tbn:ANd9GcTKOYM8AWOB8b-Wiac6R

-- Edited by Gundog on Saturday 26th of August 2023 03:30:42 PM

yobarr · Guru

Gundog wrote:
I think it's a quick and easy way to hook up, looks ok but I dont want a pair of Yellow or Red danglie thinks hanging off my towbar they look crap.
Then I saw alternative way of using the hooks put oversize hammerlock on the towbar and attach the the hooks to the safety chain, spray them with silver or black paint to get rid of the ugly yellow.

-- Edited by Gundog on Saturday 26th of August 2023 03:30:42 PM

Hi Graham, Without digging into my records I'll say that I'm pretty sure that only one hammerlock is allowed in any link between the caravan and the car. Probably worth checking? Cheers

Eaglemax · Guru

Gundog wrote:
I think it's a quick and easy way to hook up, looks ok but I dont want a pair of Yellow or Red danglie thinks hanging off my towbar they look crap.
Then I saw alternative way of using the hooks put oversize hammerlock on the towbar and attach the the hooks to the safety chain, spray them with silver or black paint to get rid of the ugly yellow.

-- Edited by Gundog on Saturday 26th of August 2023 03:30:42 PM

only one hammerlock is allowed in the chain length Gundog. Many grey nomads have crook knees, back, hips and plan to be off these areas when caravanning. Hence the interest. As this is the case I'd highly recommend the following hooks.

https://www.awardrv.com.au/mawby-hook-as4177.4-3.5t-atm-rated-towing-hook-pai

Eaglemax · Guru

Gundog wrote:
I think it's a quick and easy way to hook up, looks ok but I dont want a pair of Yellow or Red danglie thinks hanging off my towbar they look crap.
Then I saw alternative way of using the hooks put oversize hammerlock on the towbar and attach the the hooks to the safety chain, spray them with silver or black paint to get rid of the ugly yellow.

-- Edited by Gundog on Saturday 26th of August 2023 03:30:42 PM

only one hammerlock is allowed in the chain length Gundog. Many grey nomads have crook knees, back, hips and plan to be off these areas when caravanning. Hence the interest. As this is the case I'd highly recommend the following hooks.

https://www.awardrv.com.au/mawby-hook-as4177.4-3.5t-atm-rated-towing-hook-pai

-- Edited by Eaglemax on Saturday 26th of August 2023 05:02:23 PM

Eaglemax · Guru

and they are red not yellow :)

67HR · Senior Member

This utube video may solve some of the confusion regarding these "mawby hooks"

Hope it helps

Trev

https://youtu.be/oemjGl4HgRM?si=0Z59XuKX7XXnsxXq

shakey55 · Senior Member

Gundog wrote:
I think it's a quick and easy way to hook up, looks ok but I dont want a pair of Yellow or Red danglie thinks hanging off my towbar they look crap.
Then I saw alternative way of using the hooks put oversize hammerlock on the towbar and attach the the hooks to the safety chain, spray them with silver or black paint to get rid of the ugly yellow.

-- Edited by Gundog on Saturday 26th of August 2023 03:30:42 PM

I like your thinking, BUT what happens when there is a need to tow another trailer, and that trailer does not have hooks attached to their chains. Can you then attach those chains to your attached hammerlocks with shackles.

landy · Guru

Greg 1 wrote:

Can't say that I am a fan.
Will stick with my rated shackles me thinks.

Me thinks the same Greg.