OT - steel cable safety related question

I have heard of people putting a blanket or heavy coat over a cable when winching a 4x4 that is stuck. Why the blanket? How can the blanket absorb significant energy if the cable should break or pop off? The reason for these questions is that I am about to pull in a wall on a house using several 4 ton come-alongs and a chain hoist. I intend to work as safe as possible.

Reply to
aribert
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I don't know, but two thoughts.

Maybe it allows a visible indication of tension. Any weight such as a heavy coat or such will cause a sag in the cable under tension, and may therefore give the operator a visible indication as to tension.

Maybe the thought is just to try to keep any cable from whipping UP if it breaks. Get it low and away from heads, etc, and it would also have some energy absorbed if it has to snake across the ground.

Interesting question.

Brian Lawson, Bothwell, Ontario.

Reply to
Brian Lawson

It will work as a parachute like on the shuttle when it lands. Gerry :-)} London, Canada

Reply to
Gerald Miller

The weight of the item on the cable deflects it into the ground if it breaks. It also absorbs some of the energy of the break by offering resistance to the motion of the broken cable.

Reply to
Steve W.

On Thu, 29 Mar 2007 02:08:10 -0400, with neither quill nor qualm, "Steve W." quickly quoth:

It won't deflect a broken cable much but it does slow the errant hook significantly should it come loose from the attachment point.

Reply to
Larry Jaques

It acts as a damper to slow a broken cable to sub-sonic speeds. Fewer lost limbs, heads, etc.

Cheers Trevor Jones

Reply to
Trevor Jones

It can't hurt. In the military we had to run

3000 psi air lines around and we'd sandbag them every 3 feet to reduce the whipping if they broke.

You could rope the cable to a sandbag every few feet if you were really worried.

Reply to
Jim Stewart

It acts as a high air resistance damper to keep snapped cable parts from traveling too far and or whipping across the job site. Since cables normally break near or at the ends, 2 blankets are probably better. It probably also acts as a safety warning to bystanders.

Come alongs are not anywhere near the issue that winch cables pose. The issue is how much energy is stored by stretching the cable. At the same breaking strength, 100' of 1/2" winch cable has 40 times the stored energy of 10' of 1/4" comalong cable.

If you are mov> I have heard of people putting a blanket or heavy coat over a cable when

Reply to
RoyJ

Reply to
aribert

The eye bolt is the weak link. The need to rethink it not for safety, but for getting the job done. It's not a safety issue as the eye bolt will fail gradually.

You need to eliminate the eye bolt and run your cable (or a piece of chain) *around* the top plate. Yeah, I know, it means making holes in the wall. Even better would a piece of 4 x 4 on the outside that the cable/chain would go around. This would distribute the force better.

This opinion is certified to be worth exactly what you paid for it, Bob

Reply to
Bob Engelhardt

I did exactly that a few years back on an attached garage on a stucco house. I had 2 comalongs pulling the walls in, nothing moved. Then I put a post between the ridge line and the ceiling joists and a bottle jack/post on the garage floor pushing up on the ceiling. Much creaking and goaning while the whole roof pulled into a new shape.

I would not be too worrried about flying cables, wood rafters are just too soft to allow the kind of rigid loads that will cause that kind of failure. When they fail you will hear some cracking and splintering sounds and the cable going limp.

You really need to pull from the outside. Put a 2x6 or 2x8 on the outside, drill through and use a forged eybolt, NOT an a bent eyebolt. You can also make some attachment plates from 1/4" plate bent at 90 degrees with a bolt hole on one leg and a hook hole on the other leg. I'd be looking at 1/2" bolts minimum, more like 5/8" bolts.

You will need to add some collar ties when you are all d>>Thanks all for the replys. I am somewhat concerned about the ends of the

Reply to
RoyJ

Steel cable and tensioners are usually used to help old wooden barns/buildings.

You could also consider screw jacks. Make sure you brace the ends right.

Reply to
Epictitus

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