Horizontal Lifelines and ratchet straps.

[Seano]

Following a post elsewhere, I came across this picture in a manufacturer's catalogue:

 

http://i116.photobucket.com/albums/o3/deepsoup/dodgycat.jpg

 

This shows a bit of bad practice that I see all the time, so its obviously easily done. It bugs the hell out of me from 100 paces, so it just seems weird that its apparently so hard to spot, and yet here it is plain as day in the manufacturer's catalogue so I guess it can't be that obvious after all.

On the upside, it can be put right in about one second and requires approximately zero effort. Close the handle on the ratchet dammit!

 

Lets have a closer look at the ratchet mechanism itself for a second:

 

http://i116.photobucket.com/albums/o3/deepsoup/ratchetbody.jpg

 

The teeth of the ratchet are pretty obvious, and there are two spring loaded bars that engage those teeth, I've painted them red to make them easier to see.

As you open the handle, the bar there engages with the teeth and turns the wheel around, the bar in the body is pushed out of the way as each tooth goes by. Click, click. As you close the handle again, the bar in the body engages with the teeth and holds the wheel where it is as the bar in the handle rides over the teeth. Click click. All good so far.

 

Now, that bar on the handle serves another couple of functions.

When the handle is fully closed, it drops into a slot in the body of the ratchet device, which 'locks' the handle in the closed position. This is in itself a good thing, because the ratchet is released by opening the handle fully and that's not something you would want to happen accidentally (say if something were to snag around the handle)*.

 

At the same time, it engages with the next set of teeth around the ratchet from the ones that are engaged with the sprung bar on the body. This provides a degree of redundancy, because there are now 2 pairs of teeth locked into position, rather than just the one.

 

Also, when the handle is open its going to hang down, and since these lines are best rigged just over head height, that makes it just right for banging your head on. Also illustrated neatly in that first pic. If you were really unlucky, you could put a nice gash in your head and accidentally release the ratchet at the same time! (For top marks, you could then faint from the head trauma and fall off. :))

 

Its sometimes possible for the bar in the body (well, either of them really, but that one's more important) to fail to seat properly - it happens when the ratchet tooth isn't quite moved far enough to let it drop down into position, so it gets trapped sort of half-engaged. Its really obvious when you see it, but you have to look. So PLEASE, when you've ratcheted the line as tight as you want it (don't go crazy, you want "bdurdrdrdrdr" not "twang"), close the handle, then have a quick look to see that both sprung bars are fully engaged and you're done. Easy.

 

Incidentally, the same applies to common or garden ratchet straps (load restraints). The mechanism is exactly the same, the only significant difference between those and the 'lifeline' ones is a slightly more rigorous testing regime.

 

</rant>

Sean

x

 

ps: If you ever find yourself walking along a trolley-beam like this: Don't stand on the cable track you numpty! Its not strong enough.

[Droycewalker]

Ah.... A fully justified and well excecuted rant! :P

 

If it was me, however, I'd be far more worried about the fact that I appear to be glowing! Highly disconcerting!! :D

 

On a sub-note, are people really that stupid that they can't identify the fall-arrest system in what, I assume, is a safety supply catalogue? As opposed to, you know, the background.... Marketing; you've got to love 'em! :)

[Andrew C]

Have to admit, I looked at the pic and thought "What kind of idiot would use a load strap as part of a fall arrest system?" I now understand that it is a "Special" type of load strap.