Reinforcement for Rubber traction device for lariat rope

[Sandman7673]

This "bushing" is made out of 45 duro natural rubber. The traction on the lariat rope (3/8" diameter) is really good at this duro. The problem is that on very hard runs, the rope tears through the rubber. I've tried aramid fibers and pulp, and that did not help at all. Any advice on reinforcement options or alternative materials? Neoprene did not work.

Thanks.
Sandman

 

[TugboatEng]

Is the rope compressing and tearing the rubber or is the rope slipping and tearing it? The latter case becomes a heat issue. Thermally conductive material may work best. Maybe a metal filled rubber is an option?

On our fleet of tugboats the hawser passes through the bullnose of the bit and can slide around with quite a bit of force on it. We have found metal filled primers hold up substantially better than other types of epoxy primers. The others simply melt away. This isn't heat that makes the bullnose hot, it's heat at a microscopic level that weakens a few molecules at a time so they can be stripped away. Anything to get heat away from the surface will make it last longer.

If it's tearing from compression, urethane is supposed to have better abrasion and tear resistance.

 

[Sandman7673]

Thanks TugboatEng! I don't have any slow motion video, so it's a bit hard to tell exactly what is happening. But I do know there is a lot of heat generated (burned my hand countless times). What may be happening is that initial heat generation causes surface molecules to break down, then the rope runs a little (maybe 3-6 inches), but it's enough to break through a half inch or more deep into the device. Can you provide any info on a proposed metal filled primer?

 

[TugboatEng]

We use International 300V but this is a primer for metal. I'm suggesting you fill the rubber bushing itself with aluminum powder or some other conductive metal.

I'm thinking something along these lines:

https://www.google.com/url?sa=t&sou...WMAB6BAgAEAE&usg=AOvVaw0KkJjxyOTo7JXyjQASxrSZ

 

[Compositepro]

You have to consider energy dissipation. There is a limit on how much energy you can dissipate in a certain time in a certain area without creating a fire or generating forces that will certainly destroy rubber or rope. Higher coefficient of friction results in more concentrated area of dissipation.

I think the real solution to your problem is a design change. Use the outside rubber surface for high contact friction with the rope to prevent sliding against the rope. Then have the braking surface on the inside of the rubber sleeve where a rigid cylindrical friction material presses against another cylindrical surface. This will put a lot less wear on the rope as well.

Another approach would be to pass the rope through a steel vee groove. If you find the correct geometry, it may work. The vee groove is more likely to work than the other suggestion.

Look at devices used to rappel with ropes.

I do not think that you can solve your problem by simply finding the "right" material.

 

[Sandman7673]

Thanks to both Tugboateng and Compositepro for your feedback. I've considered the V-notch design, but it is not forgiving enough on the livestock or the hands. I may try the metal additive. I'm also going to see if a hdpe geogrid can be tied or fused cylindrically and placed in the mold about 1/4" below the surface. Not sure if that's possible, but I'll talk to my manufacturer. Thanks again.

 

[3DDave]

I think these are an example videos:

https://imgur.com/gallery/MCdMTRV

https://amp.reddit.com/r/oddlysatis...e_smoke_coming_off_the_saddle_horn_before_it/

Rough duty.