Best way to tie off to wire rope and determine required force

[TeejT]

I'm not wondering about terminating the rope, rather I want to attach some assemblies along a wire rope. What's the best way to achieve this? I want to clamp down on the rope imitating a wire rope clip but I can't figure out what gap to remove from the diameter profile of the clamp to achieve the required force when torquing down. How much compression do I need and how much is allowable?
Thanks!

 

[EngineerTex]

The filled space in a wire rope clip has an oval (not an ellipse) shape, the rounded ends of which correspond to the diameter of the intended wire rope. When you make up the termination of a wire rope, remember that you're putting the two pieces of the clip over the two parts of the rope and that the gap is not really measured, rather the nuts are torqued down to the appropriate torque.

The live end and dead end of the wire rope don't move past one another because of friction along with the enormous forces generated by the clip. If you're putting something other than two pieces of wire rope of the same diameter into the clip, you may run into problems if the other member doesn't generate enough friction in the clip assembly.

What are you trying to attach to the wire rope? There are devices for fastening to a wire rope mid-span other than clips. Depending what you're intending on doing, these items may work better than a clip.

Engineering is not the science behind building. It is the science behind not building.

 

[TeejT]

EngineerTex - I'm trying to attach 15 lb pods along a wire rope lowered into a well.
Do you have any examples of these devices and how to generate and calculate required grip force?
Thank you.

 

[unclesyd]

What is the size of the wire rope in question?

Do your attachments have to be any certain material?

 

[msquared48]

Wire rope manufacturers sometimes show pictures and allowables for certain connectors.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[EngineerTex]

Ok -- so we're not necessarily talking about overhead hoisting or life-or-death issues here? Or perhaps we are? The more information you post, the more chance there is that someone here can help. You don't need to tell exactly what you're hanging off of the wire rope, but it would be good to know what you planned on putting inside the wire rope clip along with the wire rope.

At 15 lbs, you would probably be ok with wire rope clips, but you may also consider swaging sleeves -- very cheap if you need to do a lot of them and have the equipment to swage the sleeves. Also consider a strain relief sock (pulling sock) -- probably more expensive than a wire rope clip, but will have a convenient loop for you to hang your "pod" onto.

You also may consider using nothing. I don't know what type of "pod" you're dealing with, but if it has a wire rope section to it, you can splice the end of it into the main body of the wire rope you're using.

What kind of well are you doing this in?

Engineering is not the science behind building. It is the science behind not building.

 

[Ussuri]

Use a thimble, wrap the rope around it. It will set your radius for you. You have a choose of termination types such as wire rope clips, or wedge sockets if you want to stay away from ferrules and spelters.

http://www.thecrosbygroup.com/html/default.htm

Click on the orange box top left which says wire rope end fittings

 

[TeejT]

We're not talking about overhead hoisting/life or death issues, just $$$ issues. LOL
The 15 lb pods are iron/steel assemblies essentially, and they are lowered into petroleum production or observation wells tied off to the wire rope. Total weight hung off the wire rope is ~ 3000 lb so either 1/4" or 3/8" rope, rotation resistant.
I'm wondering about the clamping forces required and how to calculate them. Thanks.

 

[Ussuri]

Check with the supplier.

I have attached a copy of the application notes for one of crosbys wire rope clips. The tables show you how much turnback, how many clips and how much torque to apply.

 

[unclesyd]

I had all three sites lined out to give you some idea of what was available for your application when I found a brochure for Lexeco that had a lot more options like the line stops, buttons, balls, etc. They don't have the long line snap. They are other sources that have a better selection of compression sleeves. both single and double.
I believe that a line stop would do less damage to your cable, though you might want to look at the mechanical stops that could be easily modified to hold your part.

http://www.lexcocable.com/index.html

Look at line stops:

http://www.e-rigging.com/store_Categories.cfm?Cat_ID=54&Menu_Choice=Catalog

Aluminum Oval Sleeves:

http://www.newcomfg.com/wirerope.htm

Long line snaps;

http://www.blueoceantackle.com/longline_snaps_and_branch_hangers.htm

 

[EngineerTex]

Sorry. I can't comment any more. You may be a competitor to my company.

Engineering is not the science behind building. It is the science behind not building.