Landing on a small platform with a bungee brake

14 mai, 2014 • Bungee Brake

Here is a question I received from Jason Devine in Kentucky, USA

"Hello, I'm currently using a bungee brake on our commercial zip line, but as we are trying to accommodate a wide range of weight (70-250 lb), it is somewhat difficult to manage. While our speeds are only around 25-30mph, we are trying to stop on a platform and it can be difficult. I'm wondering if the Counterweight Progressive Brake would be an option for us? We need to keep it economical so the zip stop is out of our range. I appreciate any help you can provide.

Thanks! Jason"

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Zip-Rush le 14 mai, 2014

Well,

Landing on a small platform if your riders do not use an active braking system (glove for example) is always difficult with any type of brake and even with a magnetic brake at $5,000/unit.

What I would recommend is simple. Get rid of your bungee cord and thread an 8 mm rope your operator will use to catch by hand. Ropes goes from platform to brake anchor pulley (on the ground in your case) to your brake block. Operator should be attached to a safety anchor and you may even want to add a pulley on the tower (back of platform) so your operator is pulled towards the back instead of the front when pulling on the brake rope.

This way your brake (operator) will apply more resistance for heavy people and can release almost completely for people coming in slow.

If you could run a third cable between and above the two track cable to use as an overhead brake anchor, that would be even better. Please let me know how it works out.

That is really the best you can do. Please let me know what your decision is and how it works out for you.
Jason Devine le 14 mai, 2014

Thanks for getting back with me.

Is you platform in a tree?
No, it is a free-standing 10 × 10 platform that we built specifically for landing using telephone poles as the anchor points. We have 2 side by side lines going into it.

What is the height your platform?
The platform is 13 ft above ground.

What length do you have between the anchor point (tree) and the edge of your platform?
It is approx. 9 ft from the pole to the front edge of the platform.

Do you always have an operator at landing?
Yes, we currently always have an operator at each of the lines at the landing

How far from the attachment point is you bungee attached to?
We have tried several different distances. The brake is tied off approx. 25 ft. in front of the platform on the ground at an angle to keep the rope of the way of the rider. We’ve attached a couple of smaller ropes to the brake as well so that we can pull it in some for lighter weight people. Obviously, this causes the bungee to get much tighter and we have just enough stretched bungee length to place another clip behind the brake to keep it from making them a slingshot back up the cable.

Any help you can provide will be appreciated.
Zip-Rush le 14 mai, 2014

Hi Jason,

Can you tell me:

Is you platform in a tree?
What is the height your platform?
What length do you have between the anchor point (tree) and the edge of your platform?
Do you always have an operator at landing?
How far from the attachment point is you bungee anchored?

I’ll try to find you a solution but I do not think a CPB is possible as it is not for landing on small platform; you would have the same problem than with the bungee.

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