Elastic Potential Energy Stored in Surgical Tubing: What are the legal limits?

[paul.dornfeld]

We want to project our arm that will hook on the castle tower's bar. We want to do this vertically using surgical tubing to lift the arm until it hits the stop at the top of the arm's travel. It never gets "airborne" and stays completely within the confines of its mechanism. Our question is: Is there anything prohibiting using surgical tubing, stretched and secured at the arm's base, as the means of extending the arm in the last 20 seconds. (we will have a latch mechanism in place to be sure that it won't release until our driver hits the button.) Thank you.

[AngryCalculator]

Nope. It should be fine; 2910 plans on using it too.

[paul.dornfeld]

Originally Posted by AngryCalculator

Nope. It should be fine; 2910 plans on using it too.

Thanks. Looking forward to seeing how you use it, too.

[Daniel_LaFleur]

Originally Posted by paul.dornfeld

We want to project our arm that will hook on the castle tower's bar. We want to do this vertically using surgical tubing to lift the arm until it hits the stop at the top of the arm's travel. It never gets "airborne" and stays completely within the confines of its mechanism. Our question is: Is there anything prohibiting using surgical tubing, stretched and secured at the arm's base, as the means of extending the arm in the last 20 seconds. (we will have a latch mechanism in place to be sure that it won't release until our driver hits the button.) Thank you.

You are specifically allowed to do this as per R35

Originally Posted by Rules

R35 Non-electrical sources of energy used by the ROBOT, (i.e., stored at the start of a MATCH), shall come only from the following sources: A. compressed air stored in the pneumatic system that has been charged in compliance with R79 and R80, B. a change in the altitude of the ROBOT center of gravity, C. storage achieved by deformation of ROBOT parts,
D. closed-loop COTS pneumatic (gas) shocks, and E. air-filled (pneumatic) wheels

What you need to be concerned with is R9

Originally Posted by Rules

R9 ROBOT parts shall not be made from hazardous materials, be unsafe, cause an unsafe condition, or interfere with the operation of other ROBOTS.

Inspectors will look very closely at your mechanism to ensure that it is safe at all times. This includes when it is being transported on/off the field as well as in the pits, etc.

[rich2202]

Regarding R9:

If there will be a lot of tension put on the tubing, then you will need a safety mechanism in case the tubing breaks. Basically unplanned sudden release of stored energy must be taken into account.

In the past, encasing the tubing in tube would suffice. Make sure the outside tube has a separate attachment so that it won't go flying off either.

[paul.dornfeld]

Originally Posted by rich2202

Regarding R9:

If there will be a lot of tension put on the tubing, then you will need a safety mechanism in case the tubing breaks. Basically unplanned sudden release of stored energy must be taken into account.

In the past, encasing the tubing in tube would suffice. Make sure the outside tube has a separate attachment so that it won't go flying off either.

Great idea. Thank you. Didn't think of that.

[Sperkowsky]

We have an assembly that works. We abandoned our climber due to our winch being all messed up though.

[GeeTwo]

From a practical standpoint, you probably don't want to stretch the surgical tubing much past twice its natural length; beyond this it tends to stretch inelastically*, especially if held there for a long time.

* that is, a permanent stretch, from which it will not return to its original length.

[paul.dornfeld]

Originally Posted by GeeTwo

From a practical standpoint, you probably don't want to stretch the surgical tubing much past twice its natural length; beyond this it tends to stretch inelastically*, especially if held there for a long time.

* that is, a permanent stretch, from which it will not return to its original length.

Very important point. Thank you so much.

[paul.dornfeld]

Originally Posted by Daniel_LaFleur

You are specifically allowed to do this as per R35


What you need to be concerned with is R9


Inspectors will look very closely at your mechanism to ensure that it is safe at all times. This includes when it is being transported on/off the field as well as in the pits, etc.

Thank you. Just what we needed. Good advice, too.