Optimizing Weight Distribution for Dog Agility See-Saw Compliance

[Jillity]

TL;DR Summary

A question of weight ing a see-saw came up this morning. Can you help?

This question came up in my dog agility class this morning.
My instructor had bought a new see-saw for the dogs. The Kennel Club regulations say,

'The See-Saw must start to tip and then touch the ground between2–3 seconds after a weight of 1 kilogram has been placed in the middle of the down contact area. The down contact area is 914mm long.
The see-saw plank is firmly mounted on a central bracket. The length of the plank is 3.66m. The height of the central bracket as measured from the ground to the top of the plank is between 610mm and 685mm.'

My instructor had tested the new see-saw with her dog and found she needed to weight the side with the down contact in order to comply with the Kennel Club regulations. When she did this however, the see-saw failed to tip back again when the dog had alighted.

How should the see-saw be weighted so that the see-saw tips back after the dog alights but still complies with the regulations? Would it be necessary to move the fulcrum?

 

[256bits]

Hi Jillity,
Interesting problem.
Odd that a manufactured product wouldn't perform without complications out of the box.
I suppose she had to put the thing together after purchase.

After adding the weight, and running the dog through, the see-saw does not return by itself to the next run position. What if you return the see-saw back manually - does the heavier side stay down.

Firstly, I would check if the fulcrum is in the middle, or how far from the middle. Is a couple of inches about right to make one end suitably heavier than the other. Just use a measuring tape to check the lengths.

It could be that the "bearing" is too tight, or something is out of alignment there. You could check that there is no binding and the see-saw moves up and down rather freely. Some adjustment might help.

 

[A.T.]

The See-Saw must start to tip and then touch the ground between2–3 seconds after a weight of 1 kilogram has been placed in the middle of the down contact area.

How long does the unmodified see-saw take?

 

[Jillity]

I wasn't there when my instructor tested it. She fixed a block of wood under the down contact end of the see-saw so that it would tip in the correct length of time. She said that if the block of wood was moved it threw thew whole thing out which it would do. I balanced the see-saw so that it stayed perfectly balanced for a little while and then it gradually returned to the correct position. This means that the up part of the see-saw must be slightly heavier than the down side even with the block of wood. I shall have to take a tape measure up there next time. Without the block of wood it would return to the correct position. I'm wondering if she's using the correct base for the see-saw. I'll have another look and take some measurements.