Thread: How much load?

The rated Safe Working Load ( SWL ) is usually a factor of the Max Load. In this case a 10 to 1 safety margin. If you lift a 1.5 tonne log you have reduced the safety margin to 2 to 1. The further you go past the SWL the smaller the safety margin you have. Don't go lifting at the Max Load; you are just asking for trouble.

Mike

That's a bit of a humdinger you've asked there WB.

From my understanding 300kg SWL means that the safe loading point is at 300kg but is that for Lift load whereas the 3000kg Max Load is for Pulling??? It's a bit of a conundrum isn't it

What type of pulley is it? Got a link or a Pic that we can look at?

Thanks, I figured as much. These pulleys are often used with people as the load (winching yourself up into trees etc) in which case you would respect the 10:1 safety factor.

When I am safely winching a log perhaps 30m from the drop zone or 30m from an area likely to cause injury in the case of equipment failure, I won't respect the safety factor quite as much although I will keep well below the maximum rating.

How does that sound?

Originally Posted by DJ's Timber

What type of pulley is it? Got a link or a Pic that we can look at?

Fourth Pulley down from top

Originally Posted by Wood Borer

Thanks, I figured as much. These pulleys are often used with people as the load (winching yourself up into trees etc) in which case you would respect the 10:1 safety factor.

When I am safely winching a log perhaps 30m from the drop zone or 30m from an area likely to cause injury in the case of equipment failure, I won't respect the safety factor quite as much although I will keep well below the maximum rating.

How does that sound?

Sounds OK to me.

Mike

Simple if you exceed the SWL then dont stand under it without crossing your fingers!


Ross

I wouldn't use this one for the application you have outlined. Just look at the specs of the snatch blocks made by beaver and ARB both are rated to 7/9000kgs. I'm a qualifiied Crane operator and Dogman and understand the safety issues that this raises. There are many people out there that have been hurt and even killed by useing lifting gear that wasn't up the standard.

Just my 2c worth.

Robert

Originally Posted by Wood Borer

Thanks, I figured as much. These pulleys are often used with people as the load (winching yourself up into trees etc) in which case you would respect the 10:1 safety factor.

When I am safely winching a log perhaps 30m from the drop zone or 30m from an area likely to cause injury in the case of equipment failure, I won't respect the safety factor quite as much although I will keep well below the maximum rating.

How does that sound?

in a word dangerous

If I'm looking at the right pulley, the stated SWL is related to potential failure of the 13mm rope where it bends to pass over the sheave, while the max load is related to failure of the pulley itself.

with a 50mm sheave, you would want to be using a rope with a diameter of 4 to 8mm if you intend working up towards the pulley's max load.
Don't forget that draging a 1.5t log takes a lot more force than lifting the same log because of friction with the ground.


my thoughts are at 1.5t you need a much larger sheave.

the "rule of thumb" is taht a sheave 100x the rope's diameter gives you full rope strength, anything less reduces the load the rope can lift.


ian

Thanks for your replies and excellent advice, very much appreciated.

The new pulley I will now only use for light loads including myself.

I have a much bigger ARB snatch block which I currently use, the new one was purchased partly for climbing and as a back up in case I need to redirect.

The big ARB snatch block I use for 4WD driving in conjunction with a winch.

Hi Wood Borer

Under occupational health and safety law (OHAS) the safe working load (SWL) includes a safety margin as previously pointed out and when lifting something it is a figure never to be exceeded. ie In an industrial situation you cannot legally lift more than 300 kgs. If you exceed 300 kgs and there is an "untoward event" it has probably moved from being classified as an accident to negligence or gross negligence.

Very significant legal, liability and insurance issues.

I have no idea what the situation is if you are dragging something rather than lifting it.

Cheers

Graeme