Para TPS (Titanium Pulley System)

Para TPS User Manual

What is it?

It’s a Universal Pulley System made from Grade 5 Titanium used for making work easier and more fun no matter what you’re doing. Designed for Paracord, or your favorite other 4mm line.

OK, So what would I use it for?

Soooo many things!

Anything you need to move or lift. Let’s say you’re mountain biking and a log or large rock has fallen in the trail. Luckily, you have these pulleys with you and can use them to move the object out of the way without breaking your back.

Combine these little workhorses to get stuff done. The small TPS2 could be used to keep your food out of reach of bears and other critters in a reduced friction bear bag system. This helps to save wear and tear on your line and the tree.

If you want to send some gear across a creek or river, each pulley was designed so it could be used as a zip line shuttle. You could even make a dog run for Fido while camping.

If you’re a hunter and need to lift or pull your deer you could use the TPS4-4 or TPS5-5 to create a 5:1 mechanical advantage.

They are made from Titanium, Acetal and Stainless. They work great in a harsh environment such as say, the ocean. They could be used on a fishing boat or as a sailing block. These are just a few examples of the almost endless possibilities.

For me, any reason to play with them and see what they can do. My dad even uses the Para TPS to lift the front of his riding lawn mower so he can clean the underside.

I posted an update video showing Para TPS in Action. You can see it by clicking here.

Design and Materials

These little guys went through a whole bunch of revisions before they became the super awesome pulley you see today. I did most of my design changes in a 3D CAD system first until I got one that was close to what was in my head. Then I started making plastic printed prototypes.

I know some of you might be thinking that the pockets in the prototype side plates look pretty cool, and they do! But once I started doing my Finite Element Analysis (FEA) to calculate the stress and strength of the system, I had to take them out. I was looking for a factor of safety (FOS) of 3. In other words 3 times stronger than the load that would be on the pulley during normal use.

Based on using paracord with a breaking strength between 650lbs.-750lbs., a FOS of 3 puts the maximum breaking strength (MBS) of the pulleys around 2250lbs. These numbers have only been tested on a computer using the FEA. This is part of why I need support from you as a backer. Once this campaign successfully ends, I will take a full set of pulleys and run them through load testing. Load testing will basically involve ripping these little pulleys apart, and we’re going to catch it all on video so you can watch. These tests are important to make sure that they are strong enough and safe enough to handle whatever you can throw at them. The final product will be laser engraved with its MBS and also a logo. The logo will serve as an Identifier so you can trust that you’re getting an authentic and tested product.

Once I was happy with the design I sent the side plates off to be water jetted and fired up my lathe to make the sheaves and pins.

I spent a lot of time to determine the design and materials I wanted to use. The Side Plates and Pins are made of Grade 5 Titanium (Ti-6Al-4V) because of their strength and corrosion resistance. The Sheaves are made of (Homopolymer) Acetal (A very strong plastic that is used for bearings because of its low friction). The Retaining rings are made of stainless (304SS made by Smalley).

The Stainless Version will be made from 304SS for the Side Plates and Pins. The Sheave & Retaining Rings with be the same as the Titanium Version. The Stainless Version will be heavier and not quite as strong as the Titanium Version, but are more budged friendly.

By using retaining rings, the side profile of the pulleys stay small. The pins do not stick out from the side plate as much as a nut or head of a bolt. This means they are less likely to snag on branches. Each pulley can still be serviced if needed using common tools.

I chose these materials because of the strength and corrosion resistance of titanium and stainless and the machining and bearing properties of Acetal.