Wednesday, March 23, 2016

Review: Para TPS Pulley systems

I love paracord. I love titanium, I love pulleys, I love Kickstarter so when a titanium paracord pulley came up on Kickstarter, I knew I had to get on board. I've covered a titanium paracord pulley system before, in the Ti2 PB-9 Parabener systems which live on my daypack, just in case. However, they are pretty chunky, being loaded with other features, and might be overkill when all you need is some lifting and shifting.

That's where there the TPS system comes in. A bare bones pulley system, it's a Universal Pulley System made from grade 5 titanium and ready to be used for making work easier and putting no matter what you're doing. Designed for paracord, or any other 4mm line of your choosing.

The TPS pulley systems are available in four formats, the TPS-2, TPS-3, TPS-4 and TPS-5. the number value corresponds to the number of "sheaves" which are the wheels inside the pulleys, designed and produced by Andrew of Root Designs R&D .

Root Designs spent a lot of time determining the design and materials they wanted to use in these pulleys. The side plates and pins are made of Grade 5 titanium (Ti-6Al-4V) because of its strength and corrosion resistance. The sheaves are made of a homopolymer acetal (which is a very strong plastic that is used for bearings because of its low friction coefficient, perfect as sheaves). The clip-in retaining rings are made of stainless (304SS made by Smalley).

Some serious design and research went into the development of these. Based on using paracord with a minimum breaking strength between 250-340 kg (650-750lbs) for Type III to IV paracords, a FOS of 3 puts the maximum breaking strength (MBS) of the pulleys around 2250lbs. These values were tested on a computer using failure-and-finite-element-analysis software. Bearing in mind that most civilian paracord is type II to III, with minimum breaking strengths of 180-250kg, (550-650lbs). Doing these studies are part of why Root Designs needed support from crowdfunding.

Having gone through rounds of testing and prototyping, they have pulley systems now rated for a Working Load Limit (WLL) of 68kg (150lbs) and a Tested Breaking Strength of over 900kg (2,000lbs). What does that mean? it means the TPS is recommended for loads of around 68kg, and is known to catastrophically fail at 900kg. Given type III paracord will take at least 250kg, my money is on the TPS working long after the paracord snaps, if you're looking at points of failure.

What's the big deal with pulley's in the first place? Mechanical advantage! Anything you need to move or lift, these pulleys can offer up to a 5:1 mechanical advantage with paired TPS-5's. By setting them up in sequence, and threading paracord through the sheaves correctly, the power of simple machines can reduce the effort needed by up to 1/5th of the force needed by a single loop alone. A single pair of pulleys halves the effort, three, a third and so on.

I backed for and received a twin set of TPS-5's and also got a TPS-2 as well. They can be used in a variety of combinations, or singly depending on your situation and need. One thing to remember that with all pulley systems, your ability to lift is only as good as your weakest component. Any attachment accessories (I've used two steel S-hooks from Ikea, so useful) as well as Type 3 paracord. However you also need to take into account the features of the load, and it's ability to haul itself, as well as whatever you are mounting your load too.

The other aspect to be aware of is the length of cord used. For every sheave used, the length of "fall" between the sheaves increases. This needs to be taken into account when reeving (lacing) the pulleys.

Pulley systems mean that someone with little hands and arms, like Tactical baby, can lift this 2.5L kettle full of water, and hold it, in her non-dominant hand, and nonchalantly pose for photos before bedtime.

Here's a tidbit of information from the Royal Canadian Sea Cadets Seamanship manual,
Parts of the Tackle:
a. Standing Block: The block that is anchored and is not moving. This block changes the direction of the running part.
b. Moving Block: The moving block is attached to the moving end of the rope (the end the cargo is on).
c. Fall: The fall is the rope that is rove through the block.
d. Standing Part: The standing part does not move. It needs to be secured to either the standing block or some other fixed position.
e. Hauling Part: The hauling part is the part that is pulled.

But acting as mechanical advantage gaining simple machines aren't all the TPS can be used for, you can combine these little workhorses to get other tasks done too. If you need to send some gear across a ravine, creek or river, or between abandoned buildings in a desolate wasteland, each pulley was designed so it could be used as a zip line shuttle. Setting up a static line and fitting one of the TPS's on it, with either one, two or three sheaves to spread the load over the line means you have a very stable and secure system for shuttling loads back and forth.

You could even use the spare sheaves to run pilot lines to haul back and forth, as well as for suspending your load. In other applications, you could even make a dog run, or other off-ground tethering system for pets or small people whilst out and about.

I even found that by setting the TPS-5 up in a cross-woven pattern, I could make a friction belaying zip-line, in the style of the mechanical decent RACK devices offered by Petzl

Being made from titanium, acetal polymer and stainless steel, they work great in harsh environments such as the ocean, or gritty, hot environments. They could just as easily be used on a fishing boat as in the bush. The limits to their application is really up to your imagination, and material strengths you have to work around.

One of the really nice design features is their small profiles. By using clipping retaining rings, the side profile of the pulleys stay small. The TPS-2 is5/8" x 1-1/2" x 9/16". The TPS-5 is 2-1/2" x 1-1/2" x 9/16".

Basically pocket sized, no matter how you put it. The pins do not stick out from the side plate as much as a nut or the head of a bolt would, which means they are far less likely to snag or catch, as well as reducing weight The TPS-5 weighs 45g (1.6oz) and the TPS-2 a mere 18g (0.6oz). Each pulley can be user-serviced if needed using common tools, and spare parts are available from Root Designs on their website. They also offer a snap-bolt which can be fitted in place of the machined pin, around the existing sheave, to offer a built-in attachment point in the place of any of the existing pins. This is an awesome addition to have designed in, and I'm kicking myself that I didn't put in for some with my pledge. However, there's nothing magic in the bolts, and it is just a matter of finding a bolt which fits, and somewhere to shackle your pulley!

 This is the kind of gadget that you probably wouldn't think to pack in your bug-out-bag on first pass, but to kit out a minimalistic problem solving swag, you could do a lot worse than including a set of TPS's to give you an advantage over your environment!

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