pic: hmmm.

[Joe Johnson]

Originally Posted by billbo911

I think it may actually be under designed. That's right, under designed.
<snip>

I get that the tending stress is roughly (Mc/I = 12Mc/bh^3, c=.5, b=.25, h =1, M= 150lbs at 2in = 300in-lbs) = 7200psi add in normal stress of (F/A = F/bh) = 600 psi and you are still under 8,000psi. Well under Aluminum's yield stress.

I don't see buckling being a problem... ...plenty strong for me.

Joe J.

[jamie_1930]

Chad disagrees, but I think your bluffing.

[carbuff2228]

alex i definitely think that this means you are going to hang

[Alex Cormier]

Haha, some nice replies here.

It's not that large or heavy, just a quick build from off the shelf materials.

There is a reason for the amount of standoffs...

[Alex Cormier]

Now that we are done competing with it. I can go into a little bit more detail about it. The hook weighs around 1lb. Not bad for an entire arm assembly with a weight of 6lbs to get an easy 2 points.

Now, does it still look "over engineered"?

We wrapped the winch cable in and out of all of the stand-offs, for one reason. Stability, I was scared that we would rip out a stand-off or the cable if we only put it around one of them. We never had a issues with it all and I was very happy.

[Joe Johnson]

Originally Posted by Alex Cormier

Now that we are done competing with it. I can go into a little bit more detail about it. The hook weighs around 1lb. Not bad for an entire arm assembly with a weight of 6lbs to get an easy 2 points.

Now, does it still look "over engineered"?

We wrapped the winch cable in and out of all of the stand-offs, for one reason. Stability, I was scared that we would rip out a stand-off or the cable if we only put it around one of them. We never had a issues with it all and I was very happy.

I, for one, love this little enigma. Strong, light, easily built in a HS shop class. It gives me a warm fuzzy feeling when I imagine it holding 150lbs of blood, sweat and tears several feet above the hard floor.

Imitation is the sincerest of flattery... ...I stole the entire idea for 2849's hook once we ran out of weight for our pole climbing arm. You'll see something very like it in Baltimore over the next 3 days...

Joe J.