Another aerial friction rigging device?

JMerritt · May 28, 2020

flushcut said:
As Tom said get a patent on it.

That’s why I’m not posting pictures. I’m working on protecting it. Patents are such a racket, and really not there to protect inventors. They are for protecting corporate IP. But, we work within the system we have I guess

Luke Haas · May 28, 2020

I love my rigging wrench!

Merle Nelson · May 28, 2020

Luke, would you be willing to start a thread and educate me/us on how you use that?

I would certainly appreciate it.

Marsupilaami · May 30, 2020

All of the current devices are 'resistance amplifiers' for lack of a better term. They amplify whatever resistance is put on the rope before them. I would like to see an adjustable resistance incorporated in a brake so that the climber can decide how much it brakes by itself.

chiselbit · May 31, 2020

Here’s what I don’t like about the triple thimble and safe-bloc, not bashing them. They are both great tools and I use them a lot but I don’t like how the load can press the rope against the tree and increase the friction.

Tom Dunlap · May 31, 2020

A very clever friend of mine suggested using a small torque converter in reverse.

An adjustment could be built in with a Bluetooth controller so that the rigger/cutter could make changes remotely.

Turn it completely open for trading the rope end back up. Then preset a load for the drop

Any Canadians here might know @Dave Spencer as the second place winner in ‘Canada’s Biggest Know it All’.

Merle Nelson · May 31, 2020

Sounds great Tom. Would that need to be set in place with a small crane?

Tom Dunlap · May 31, 2020

When Dave was thinking about a torque converter he found many that were compact. Much smaller than a Hobbs or GRCS but bigger than the biggest rigging block arbos use...but not much

Marsupilaami · May 31, 2020

Just one question... When the rope is braked directly, it takes with it part of the heat. If you hold it in a wheel and brake the wheel, the brake has to absorb a larger part of the heat. Will that be an issue for the torque converter?

colb · May 31, 2020

I know what you're making, @JMerritt , lol. Been thinking about it for some time, but I don't fabricate or invent yet. Go get some.

Tom Dunlap · May 31, 2020

@Marsupilaami

I’m not sure how to answer your question.

If I recall the rope would pass around a tight Vee like you find as the self tailing mechanism on a yachting winch. Instead of a ratcheting mechanism the torque converter would control the rotation

All of this discussion was on the original Arbo discussion forum hosted by ISA No archives

Merle Nelson · May 31, 2020

Well....that was a blunder - no archives.

Bart_ · May 31, 2020

In old mechanisms they used the non-linear air resistance to be progressive in regulating speed/power. Bit of a mind bender to imagine a fan/turbine braking a log drop. But, air is plentiful, free, cool supply to be had and just keeps taking a beating. On those DB Sala escape descenders they reach a progressive load/speed regulation by picking springs for the centrifugal brake shoes in the clutch assembly, but the drum and clutch shoes take a definite beat down and wear out, degrade their performance and need maintenance. And get hot. However, they behave a little like hydraulic resistance having speed dependence. Toughie is shock load proofing any mechanical powertrain sections.

Hardeehar, imagine the groundie having a helicopter collective stick to control the drop. Shouts "Flair!!!" "Good auto rotation on that one ..."

Jamie, been meaning to ask you what model mill you got? Do you have electronic speed control? I put a dc drive on mine and never looked back or budged a belt.

Marsupilaami · May 31, 2020

Tom Dunlap said:
@Marsupilaami

I’m not sure how to answer your question.

If I recall the rope would pass around a tight Vee like you find as the self tailing mechanism on a yachting winch. Instead of a ratcheting mechanism the torque converter would control the rotation

All of this discussion was on the original Arbo discussion forum hosted by ISA No archives

I am picturing a ratchet block as used for sail sheets - they have textured or ridged, gripping sheaves - only instead of the sheave being locked one way, it is only breaked. Rope could be pressed into the sheave by a spring.

There could be a traditional, 'solid state' 'resistance amplifier' after it, which I imagine makes it easier to design.

Ideally the breaking force should be constant, for minimum anchor load.
So I don't see a centrifugal clutch helping.

Chaplain242 · May 31, 2020

Tom Dunlap said:
A very clever friend of mine suggested using a small torque converter in reverse.

An adjustment could be built in with a Bluetooth controller so that the rigger/cutter could make changes remotely.

Turn it completely open for trading the rope end back up. Then preset a load for the drop

Any Canadians here might know @Dave Spencer as the second place winner in ‘Canada’s Biggest Know it All’.

Add in a battery winch for pre tension?

Tom Dunlap · May 31, 2020

More cleverness

surveyor · May 31, 2020

Maybe a traditional rack with larger bollards that are free to slide up or down the frame, with a spring at the bottom of the frame ends pushing the bollards together. The number of bollards engaged would be determined by the user and the weight of the load. Then when the load is taken by the rack, the spring would allow the bollards to spread out a bit acting like a shock absorber especially if the load is dropped onto the rack.

southsoundtree · May 31, 2020

A mini ratcheting bollard would be sweet.

JMerritt · May 31, 2020

Bart_ said:
Jamie, been meaning to ask you what model mill you got? Do you have electronic speed control? I put a dc drive on mine and never looked back or budged a belt.

I bought a precision Matthews 25 with dro. It has electronic speed control with two position belt for high and low range speeds. For my needs this machine is perfect. My only complaint with it is the short quill travel (2”), but it has a dovetail z axis so that makes up for it somewhat. I bought the stand with it but had to lift the whole thing 8” to get the table to a comfortable working height. The whole thing cost less than $4000 and is small enough to fit in my little shop

Bart_ · May 31, 2020

I looked up your machine. Nice. You're in the world of R8. Tip - keep a nice 6" adjustable for the drawbar and many other things. Make a small 3 or 4" 2x4 cutoff and use it as a hammer to pop the collet wedging when loosening, pound with the end grain. My machine takes one or two good taps to break free. One hand tapping, other holding the tool which may drop out of the collet as you tap. Likewise, one hand on tool, finger spin draw bar, then snug with adjustable while still holding. This will become 2nd nature.

Consider some type of hour meter for wear and tear.

It almost never hurts your tools to cut slower or lighter than for production, and prolongs tool life. No need for smoke except on stainless.

Also, old saw files that don't do well on chains are still great for regular metal work. Different standards of performance.

They don't sell my machine anymore. Its about 600 lbs with about 4" cylindrical vertical, similar table movements and sizes to yours. 4 T slots. manual feed, 0.001" dials. no dro. R8. 5" quill travel plus head vertical repositioning. Even with 5" I bought a short set of drill bits fractional sizes, saves my bacon every so often.