pic: S.W.A.T. 771's Robot

[CD47-Bot]

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[Duke 13370]

does the pneumatic hook thing work?!?!?

I would think it wouldn't be strong enough to hold the robot up.

[trev2023]

Originally Posted by Duke 13370

does the pneumatic hook thing work?!?!?

I would think it wouldn't be strong enough to hold the robot up.

I would bet that it definitely does. The top half of the design that we used for our robot this year is almost exactly the same as this robot (with the pneumatics lifting the arm and then the 2' pneumatic extending to grab the bar), and we were able to hang pretty regularly.

[Yan Wang]

Our team's robot hangs on a 1/4" aluminum shaft which was machined from 1/2" stock. Calculate the strength and you'll find it works just fine. SWAT's hook looks more than ample for the task of hanging. I look foward to seeing them in Canada again.

[Steve W]

The onle problem I can see is bending of the piston if pushing and shoving goes on (it did in Pittsbugh). Again I see Mildred as much improved over last year. This team has made amazing strides since year 1. Keep it up girls and I will see you at CR.

[Vince lau]

the robot looks good girls, your robot designs are getting better every year. see you at the Canadian regionals

[Aylish771]

Hey Everyone,

The piston we are using to hang has a 10 inch stroke length, and 2 inch bore. It will actually hold up to 180lbs at 60psi. When our team was trying to decide how to hang, we tried numerous methods on our robot from 2003. This piston proved most effective and surprisingly, lightest, which was a big factor for us this year.

Thanks everyone for all of the support! And yes, us girls have definately come a long way from "The Box That Rox". Can't wait to see you all at the CR!

[Max Lobovsky]

Originally Posted by Aylish771

Hey Everyone,

The piston we are using to hang has a 10 inch stroke length, and 2 inch bore. It will actually hold up to 180lbs at 60psi. When our team was trying to decide how to hang, we tried numerous methods on our robot from 2003. This piston proved most effective and surprisingly, lightest, which was a big factor for us this year.

Thanks everyone for all of the support! And yes, us girls have definately come a long way from "The Box That Rox". Can't wait to see you all at the CR!

it is actually less than 180 lbs because you are retracting the piston so you must subtract the area of the piston shaft. Regardless, id be afraid of bending like steve pointed out. Id be interested to know exactly how much stress that piston could take...

[RogerR]

Originally Posted by maxlobovsky

it is actually less than 180 lbs because you are retracting the piston so you must subtract the area of the piston shaft. Regardless, id be afraid of bending like steve pointed out. Id be interested to know exactly how much stress that piston could take...

if i recall correctly, the retracting force of a 2-inch bore piston is about 180 lbs (as she said), while the expanding force is over 200 lbs.

[dlavery]

Originally Posted by RogerR

if i recall correctly, the retracting force of a 2-inch bore piston is about 180 lbs (as she said), while the expanding force is over 200 lbs.

Theoretical extension force for a 2" diameter piston at 60 psi is 188.5 pounds (force=piston surface area * pressure). The theoretical retraction force is 176.7 pounds (piston surface area during retraction is reduced by the area of the piston rod). In reality, both of these numbers are slightly reduced due to friction in the system and minute amounts of blow-by around the seals. But the total available force is still more than sufficient to lift a 130 pound robot (unless you have really whaled away at the piston rod and bent it [note to certain team members - pistons are NOT hammers!], in which case you will never lift anything ).

-dave

[Aylish771]

Thanks for clearing that up guys, as long as it can lift >130lbs S.W.A.T. is happy!

[Ilyushin269]

Team 11 is using 2 cylenders with an 8 inch stroke..... Easily can lift 200-250 lbs... as we showed when lifting ourselves and Team 25 at Chesapeake.

[Berserker]

Originally Posted by Ilyushin269

Team 11 is using 2 cylenders with an 8 inch stroke..... Easily can lift 200-250 lbs... as we showed when lifting ourselves and Team 25 at Chesapeake.

and us and 237 at the jersey regional