Agility A-Frame

[A-Dog]

Hi there,

I am building an agility obstacle for my dog. It is an A-Frame that will have sides that are 8 feet long. The distance between the bottom of the two sides is variable. The height of the A-frame will need to be adjusted between 3 feet high to 5 1/2 feet high.

I need to put a chain along the edges that will hold the A-frame together at various heights. I need to know how long the chain needs to be if, at it's lowest height, it will peek at 3 feet. The chain will be attached to the 8 foot long sides, equal distance on both sides, five feet from the bottom and 3 feet from the top of the 8 foot side.

How long does my chain need to be? I looked at formulas for finding the legnth of the 3rd side of an isosceles triange, but since I don't know the area, am I sunk? And, since I know the height from the GROUND is 3 feet, but not the height from the CHAIN, is there a way to figure out what the legnth of the chain needs to be?

If you were buying chain, how many feet would you get considering I'd put two chains on -- one on either side.

Thanks,
A-Dog

 

[TchrWill]

Hi there,

I am building an agility obstacle for my dog. It is an A-Frame that will have sides that are 8 feet long. The distance between the bottom of the two sides is variable. The height of the A-frame will need to be adjusted between 3 feet high to 5 1/2 feet high.

I need to put a chain along the edges that will hold the A-frame together at various heights. I need to know how long the chain needs to be if, at it's lowest height, it will peek at 3 feet. The chain will be attached to the 8 foot long sides, equal distance on both sides, five feet from the bottom and 3 feet from the top of the 8 foot side.

How long does my chain need to be? I looked at formulas for finding the legnth of the 3rd side of an isosceles triange, but since I don't know the area, am I sunk? And, since I know the height from the GROUND is 3 feet, but not the height from the CHAIN, is there a way to figure out what the legnth of the chain needs to be?

If you were buying chain, how many feet would you get considering I'd put two chains on -- one on either side.

The chain will be the longest when the height of the A-Frame is 3 feet.
The distance from the lower edge of the A-Frame side is sqrt(8^2 - 3^2) = 7.416 feet.

Drqw your isosceles triangle with sides of 8 ft. and a peek height of 3 ft.

The chain is attached to the A-Frame sides 3 ft. from the peek.

The half length of the chain derives from the similar triangles created by drawing the line representing the chain.

Therefore, from the similar triangles, L/2/7.416 = 3/8 making L/2 = 2.781 ft. and the minimum full length chain equal to L = 5.562 ft.

A piece of chain 6 ft. long should enable you to set the A-Frame to the heights required.

 

[A-Dog]

Yes, thank you!