Showing posts with label pulley. Show all posts
Showing posts with label pulley. Show all posts

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!

Wednesday, March 19, 2014

Review: Ti2 - PB9 parabiner pulley

I seem to be fully addicted to both Kickstarter, and awesome titanium pieces. Fortunately, this means I not only have a bunch of cool kit to play with on a semi-regular basis, as well as helping people get their ideas off the ground and into your hands, but also I have things to write about.

This is one such item, which I've been sitting on for a little while,This is another creation of Mike Bond, creator of the Sentinel s4s cache, the Sentinel X and the EDCPen (link coming VERY soon). This is the PB-9 Para-biner

The PB-9 measures 48mm x 111mm x 9.5mm thick (1.875" x 4.375" x 3/8") and weighs 100g (3.5 oz) and almost the whole thing is made from grade 5 titanium. This is the biggest of three variants, and features 9 tool options, being a very versatile tool.

There are two versions of the PB-9, in Imperial (SAE) and Metric, each offering a range of wrench openings:
SAE: 15/16", 3/4" 9/16", (5/8"), 1/2", 7/16", 3/8", 5/16", 1/4" (bit driver) MM: 24mm, 19mm, (16mm), 14mm, 13mm, 12mm, 10mm, 8mm, 1/4". I bracket out the 5/8" and 16mm wrench options because they sit in where the pulley pin and wheel reside, and I don't thing they are really accessible. the pins, split rings fastening them, the pulleys and whole assembly would need to be removed to have this option used. However, the pulley significantly outweighs the wrench need, in my eyes. Both feature a "hidden" 1/4" bit driver, inside the locking gate.

That gate is 12.7mm (1/2") or so wide, and features a hook-and-pin overlock, giving a really secure structural gate. Instead of a regular spring, the PB-9 features a torsion spring, cut from a piece of grade 5 titanium as well, as rustproof as the rest of the piece. Outstanding.

The PB-9 has two pulley options, both made from high strength bearing grade bronze 544 (The prototype pin was stainless steel, the production version is also titanium)

The single pulley option allows for lines up to 1/2" diameter, whilst the twin pulley was specifically for use with paracord. I found that it would take paracord, 3mm plastic coated clothes line, 6mm nylon sheath cord, and even the plastic coated braided steel cable from a laptop lock.


 Using two PB-9s with twin pulleys in a "double tackle" setup allows for a 4 to 1 mechanical advantage when lifting loads.
The tool also features a wedge shaped "Para-Cinch" notch for quick lashing of paracord (or as a bottle opener)

The non-pulley end also features a flathead screw-driver, whch could easily be used as a short pry-par, Mike even suggests as a box-opener. This tool has it all!




One of the things I loved about this Kickstarter was the engineering that went into it, and how that was shared. Watching the test-to-destruction clips of all three Parabiners was amazing. The fact that the prototype PB-9's broke at 1771kg (3,905lbs) is amazing. That's around the weight of a car! Having these tests, and subsequent improvements described along the way was a real eye-opener, and very heart warming.

Seeing the hooked gate go into the design, as well as the living/torsion spring enter the process really gave me a sense of being part of the experience, and has lead to an outstanding tool.All part of the Kickstarter joy.

If I had a gripe about them, it might be that the gate only opens 1/2" or so, which limits what I could clip them to directly. I certainly made do with braided steel cable, and could have used chain, just something I noted.

These are totally going into my bug-out kit, and I look forwards to being the guy with the pulley when it comes time to lift an obstacle.

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