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Tree Machine · 31st August 2007, 12:50 AM

2:1 is not right or wrong, it just is what it is.

From the standpoint of physics, a 2:1 mechanical advantage system with a frictionless pulley at the top, and on the weight is great for hoisting a dead load. But for our situation where the weight IS the climber, 2:1 doesn't serve that much advantage, only in that the friction hitch functions in 2:1.

Friction hitches, for all practical purposes, do not work well in a 1:1 system where it would have to hold 100% of the climber's weight. This is why very few tree climbers have ventured out of the 2:1 world. This traditional 2:1 rope method has been currently coined in our literature dynamic doubled rope technique (Mark Adams, Arborist News, June 2007).

Non-familiarity and general lack of availability of friction devices for climbers in our Arborist gear catalogs, as well as very little published about the two main 1:1 rope methods in our Arborist publications keeps our aerial discipline firmly rooted and growing in 2:1 friction hitch systems. That, and resistance to change. Ahead of the resistance to change, however, is just that most tree climbers do not know what other options there are.

There are other options, namely using a metal device to control friction. Coming down a dual, parallel line in a 1:1 fashion (static doubled rope technique) or down a single line (SRT). These are the other two rope methods outside of the traditional 2:1 friction hitch system.

The simple metal device can allow a climber to escape the sentence of a career limited to the less efficient 2:1 method. The simple metal device will allow the climber to use his familiar 2:1 dynamic doubled rope technique, but will also allow 1:1 static doubled rope technique, as well as SRT. The climber can choose which method to use based on which method will work best, depending on the current situation. The metal device will allow the climber to use any of those three methods, at will, in response to the ever-changing situations encountered during the climb.

Versatility and freedom. The joy of being able to choose the most efficient means. Being able to change to another method when one is not serving you well.

I honor the friction hitch for what it is. I have climbed on them all, but they are very limiting and I feel keep the climber from experiencing the full wealth of what climbing can be, from reaching his full climbing potential.

As climbing Arborists, being that we climb frequently throughout every day, we should be amongst the best (human) climbers on the planet. But if we as a profession stay stuck in the 2:1 rope method, we can only be the best 2:1 climbers and that's because what other aerial disciplines climb 2:1?

None. It's uniquely a Treeguy thing.

If we don't have knowledge of 1:1 doubled rope technique and single rope technique, we are simply isolated from the rest of the disciplines; we have our way, they have theirs.

We Arborists should know and understand both ours AND theirs and be fluent in all. That's what this thread is all about. Bringing that up as a possibility. Well-rounded expertise in all things climbing.

Since there is currently no one device that will allow all three rope techniques and cater to the unique working needs of the climbing Arborist, we're using this thread to explore current friction devices. Through Dr Storrick, his experience and his fine collection, Dr Attaway and your intense knowledge of the physics of friction, as well as the collective talents and imaginations of all the Treeworld members involved in, or reading, this thread, our belief is that, if the ideal device does not currently exist, we can create it.

To date, we have explored the simplest of simple friction control devices (ovals and rings), we have created one (pear-shaped) for the experience of showing how relatively easy it can be. We look forward to creating a design, in concept, here online using images and Photoshop. From that virtual digital design we would create the actual device and test it in the trees.

Dr. Attaway's knowledge and written work on ropes and frictional dynamics can help us with the engineering of the device here, within this forum. By being able to calculate from where, and how much friction is created in what parts of the device, over what shape surfaces, we can determine why a specific device would (in concept) work.

I think I've succeeded in making this project SEEM complicated. It's really not. We're just approaching it more scientifially rather than through the potentially endless strategy of trial and error.

I think we can explore some current devices, determine where they are strong, where they are deficient, figure out how to improve upon them (the engineering part) and then choose the superior elements, combine them with our improvements (the artistic part) and build it (fabrication).

Our 'needs list' is fairly vast and specific, so much that the design possibilities are not unlimited. In fact, our ideal device is fairly limited in its number of design possibilities. This helps.

31st August 2007, 12:50 AM	#188 (permalink)
Tree Machine Over mature heritage tree Join Date: Mar 2007 Location: Indianapolis Posts: 714	2:1 is not right or wrong, it just is what it is. From the standpoint of physics, a 2:1 mechanical advantage system with a frictionless pulley at the top, and on the weight is great for hoisting a dead load. But for our situation where the weight IS the climber, 2:1 doesn't serve that much advantage, only in that the friction hitch functions in 2:1. Friction hitches, for all practical purposes, do not work well in a 1:1 system where it would have to hold 100% of the climber's weight. This is why very few tree climbers have ventured out of the 2:1 world. This traditional 2:1 rope method has been currently coined in our literature dynamic doubled rope technique (Mark Adams, Arborist News, June 2007). Non-familiarity and general lack of availability of friction devices for climbers in our Arborist gear catalogs, as well as very little published about the two main 1:1 rope methods in our Arborist publications keeps our aerial discipline firmly rooted and growing in 2:1 friction hitch systems. That, and resistance to change. Ahead of the resistance to change, however, is just that most tree climbers do not know what other options there are. There are other options, namely using a metal device to control friction. Coming down a dual, parallel line in a 1:1 fashion (static doubled rope technique) or down a single line (SRT). These are the other two rope methods outside of the traditional 2:1 friction hitch system. The simple metal device can allow a climber to escape the sentence of a career limited to the less efficient 2:1 method. The simple metal device will allow the climber to use his familiar 2:1 dynamic doubled rope technique, but will also allow 1:1 static doubled rope technique, as well as SRT. The climber can choose which method to use based on which method will work best, depending on the current situation. The metal device will allow the climber to use any of those three methods, at will, in response to the ever-changing situations encountered during the climb. Versatility and freedom. The joy of being able to choose the most efficient means. Being able to change to another method when one is not serving you well. I honor the friction hitch for what it is. I have climbed on them all, but they are very limiting and I feel keep the climber from experiencing the full wealth of what climbing can be, from reaching his full climbing potential. As climbing Arborists, being that we climb frequently throughout every day, we should be amongst the best (human) climbers on the planet. But if we as a profession stay stuck in the 2:1 rope method, we can only be the best 2:1 climbers and that's because what other aerial disciplines climb 2:1? None. It's uniquely a Treeguy thing. If we don't have knowledge of 1:1 doubled rope technique and single rope technique, we are simply isolated from the rest of the disciplines; we have our way, they have theirs. We Arborists should know and understand both ours AND theirs and be fluent in all. That's what this thread is all about. Bringing that up as a possibility. Well-rounded expertise in all things climbing. Since there is currently no one device that will allow all three rope techniques and cater to the unique working needs of the climbing Arborist, we're using this thread to explore current friction devices. Through Dr Storrick, his experience and his fine collection, Dr Attaway and your intense knowledge of the physics of friction, as well as the collective talents and imaginations of all the Treeworld members involved in, or reading, this thread, our belief is that, if the ideal device does not currently exist, we can create it. To date, we have explored the simplest of simple friction control devices (ovals and rings), we have created one (pear-shaped) for the experience of showing how relatively easy it can be. We look forward to creating a design, in concept, here online using images and Photoshop. From that virtual digital design we would create the actual device and test it in the trees. Dr. Attaway's knowledge and written work on ropes and frictional dynamics can help us with the engineering of the device here, within this forum. By being able to calculate from where, and how much friction is created in what parts of the device, over what shape surfaces, we can determine why a specific device would (in concept) work. I think I've succeeded in making this project SEEM complicated. It's really not. We're just approaching it more scientifially rather than through the potentially endless strategy of trial and error. I think we can explore some current devices, determine where they are strong, where they are deficient, figure out how to improve upon them (the engineering part) and then choose the superior elements, combine them with our improvements (the artistic part) and build it (fabrication). Our 'needs list' is fairly vast and specific, so much that the design possibilities are not unlimited. In fact, our ideal device is fairly limited in its number of design possibilities. This helps.