funky bridge

[Lazarus2]

So, if you want the smooth action of a rope bridge combined with the high strength of stitched webbing and secure shackles, look no further.

The TreeFlex bridge has been tested to 23kN and has very secure, double end threaded, shake proof pin shackles. The bridge comes in 3 sizes; 25cm, 30cm & 35cm. Custom lengths could be made to order. The anti abrasion cover is replaceable. A suitable replacement cover has been found to be a kernmantle rope sheath of 1/2" diameter (13mm). These aren't too common - luckily I had an offcut in a rather dashing hi vis orange

Often times, when the light bulb comes on and you test the theory, it turns into a 'not quite right' disappointment. This time, the reality exceeded my expectations. The sheath was an absolutely perfect fit - unbelievable!

The rope sheath is from Edelrids 'Powerstatic Dry' 13mm rescue kernmantle ( about 5500Kg break strength!). Its the big brother to my 11mm access line, which has great visibility in the tree. Other brands may make such a larger version rescue rope (stretcher hauling). Maybe other doublebraid sheaths will fit as well.

The effect is a replaceable, smooth, tight sheath that doesn't slip or crease, with great durability. Square rope bridge without knots.

Oh yes, and all kinds of funky colours.

Pictures attached but no resizing software. Maybe someone could help with that?

 

[TreeCo]

Here you go Laz. Resized.

 

[Lazarus2]

Oooo...Magic!

Cheers TreeCo

You can see in the reflection of the bonnet that there is only one cloud in the sky - a blue sunny sky in North Wales - wonders never cease!

 

[PUClimber]

Ok so there is the regular bridge that has been covered by the cover off a 13mm kernmantile rope? Is that right?

 

[Lazarus2]

Yup.

Its a perfect fit. A couple of rounds of electrical tape at the ends stops any slippage.

Its very smooth. And, err...funky!

 

[RogerM]

I'll take it! want my address?

 

[PUClimber]

I think it's a great idea. Looking at it might seem a little fishy as in the picture you can't really see the webbing bridge or really see how the shackles are attached. I take my hat off to a genius idea. Does this make it able to be used in conjunction with a micro pulley on the bridge?

 

[Lazarus2]

Now how did I know someone would raise that question?

Picture attached - can't resize, apologies to dialuppers.

The cross section is square, so rules out a micro pulley. I don't see how the weight and clunk of a micro pulley is justified here. There is sufficient friction with a ring to give some ergonomic control from 'dumping' from side to side.

 

[Lazarus2]

Will you be at TCI expo Roger?

 

[PUClimber]

It just seemed like a valid question to be made. I climb on a glide using a micro mouse pulley. So I was curious.

 

[NickfromWI]

Why not just splice a piece of rope?

GREAT idea, though. Maybe instead of electrical tape, you could do a whipping there?

This looks like something a person could do on their own, no?

Might I suggest a no-snag bow shackle? http://www.bosunsupplies.com/products2.cfm?product=S0116-NS

love
nick

 

[Leon]

No joke, that shackle with the pin sticking out looks dangerous.

 

[Lazarus2]

Dangerous? There is nothing dangerous about the shackles leon. Quite the opposite - they were specially sourced to be safer with shake proof pins. The design makes them easily checked with a leatherman type tool or small screwdriver type bar/allen key on site, rather than hunting out an allen key. Not that they are likely to need it, but there is no excuse. The spliced bridge cannot rotate round the shackle, which means the shackle cannot rotate through the webbing.

Sharp sticky outy things like chainsaws are 'dangerous'.

Nick, a spliced bridge of rope has too tight a bending radius, and is stiff at the ends. The stitched webbing and shackles are rated to 23kN. Sure, the ends could be whipped.

PUC - If you like to use a micro pulley bridge thats fine. I just meant we ruled it out as a preferential design option along with the rope bridge, when a stitched bridge is much stronger and just as effective. Especiially with a rope sheath cover.

 

[NickfromWI]

[ QUOTE ]

Nick, a spliced bridge of rope has too tight a bending radius, and is stiff at the ends. The stitched webbing and shackles are rated to 23kN.

[/ QUOTE ]

The spliced one in the pic breaks at over 23kN, as well.

Just thought I'd throw it out there.

Is this the bridge that comes with your saddle now? It's a great advancement over previous bridges I've seen!

love
nick

 

[Lazarus2]

Hi Nick

My point with the spliced rope bridge is that it may not reach 23kN on the shackles (tight bend). Probably with thimbles? But, at the end of the day, the stitched webbing is easier on the production, does the job and is dependable.

Glad you like the sheath philosophy - we are committed to safe, practicable performance measures. I've modified as many saddles as anyone at my own risk. But I never had the answers for employers. The point with TFX was to remove that need as much as possible, so the average employed arborist would have a safe, ergonomic work station, without giving the employer more grey hairs.

Its not easy, but I think we are doing a very good job of meeting that aim.

We are looking at ways to incorporate the sheath as standard.

 

[NickfromWI]

Nope- the spliced rope bridge I use was tested to over 5000lbs on shackles with no thimbles...it's all about the type of rope you use. Your system is very good, however.

love
nick

 

[stevebullman]

paolo....looks nice, one niggle though, why do you choose those shackles? i prefer the type with the pins that sit flush...they are neater, and somehow seem less likely to undo. im sure once yours are cranked tight they're never going to come undone but thats just how i feel about it.

 

[Lazarus2]

Hi Steve

In reality, on TFX we found the shackles with flush heads look neater - thats it. I balanced this with could this pin be a problem. We found not. Then this was measured against the benefits; the pin can't self loosen. Climbers find this hard to believe, so there is a red rubber thread at the top of the pin - if the pin should loosen, this can be spotted with a glance. If climbers/employers are still concerned about it, they can zip tie the pin to the shackle. If you need to swap out a bridge on site, any set of pliers or small rod/screwdriver/small allen key will do the job (easier to find often than a specific allen key).

A very safe and effective solution to the benefits of a replaceable bridge, without incorporating knots.

The pin doesn't interfere with webbing or hardware when pointing 'up', and even if it did, its smooth edged. Its held captive by the bridge, so cannot rotate. Another reason only to use our bridge with TFX.

Hope that helps.

Nick, glad you like the sheath concept. Thanks for that.

PS: Just noticed the shackles in the picture above haven't been tightened up at all - they sit much flusher than that.

 

[Lazarus2]

NE ropes KMIII 1/2" should be the right size to make a funky bridge sheath from. Just buy a few feet for replacements. Strip out the core, stuff in the TFX bridge and bind the ends tightly with insulation tape. There are many colour options:

http://www.neropes.com/product.aspx?mid=AD5A655BCA5BFA2A6B340F8F4F462C5D&lid=1&pid=77

Make sure the end of webbing on the bridge faces 'up' so as not to catch the floating ring.

When replacing the bridge, it is best to wear the harness. This ensures everything is in alignment before screwing tight the shackles. Basic diagramme attached (rotate clockwise).

 

[RogerBerry]

Could you use 1" tubular webbing instead of rope sheath? The webbing is a little bit bigger, but you wouldn't need to take the trouble to remove the core either.