Roll Bar, or just headache rack?

[DavidD]

I started a roll bar for my Iseki today, anyone have any ideas about how strong 2x2x 3/16 tubing is when it comes to rollovers.
I am making a cross between a rollbar and a cab frame out of 2x2x3/16, eventually I will put a canopy on it.
In the front I am using two 5/8" bolts on each side through the 1/2" plate which is part of my FEL mount{this 1/2" plate is bolted to the trany with 4 bolts}
In the rear I am using 2 1/2x2 1/2 x 3/16" angle bolted and resting on the flat axle area that also supports the fenders.
I will post pictures as I go, hopefully you guys can tell me if I'm just building a place to hang a cupholder, or something that might give me some protection in a rollover.
Either way, I will at least get some "limb slap" protection.

 

[DavidD]

the start

 

[Mrwurm]

David, while I could'nt possibly guess at the relative strength of your roll bar project, I would be temped to think that any roll bar will offer more protection than no roll bar. Most things that I build myself are stronger than necessary. I usually am not thinking about saving a certain number of $$ per unit like the manufacturer. I have a feeling that you, like most TBN members, have the instincts to know what is adequate for your application. Good luck with the project.

Jerry

 

[wroughtn_harv]

Wow.

Some points I'd ponder if I was going to build some roll over protection.

I've built some cages for kid's go carts over the years. Not just a roll bar but actual cages similar to what you see on sprint cars. The thing that I tried to impress onto the parents was that a cage without an attached seatbelt was actually more dangerous than a cart without a cage.

So keep that in mind. Before they came up with arm restraints sprint and midget drivers weren't killed in crashes with the new cages. They just lost arms. Used to be more than one or two on the circuits that were missing a limb.

So I'd move the bar as far away from the seat as I could while keeping the strength. I'd make it as wide as I could. I'd go the width of the tires. It'll catch tree limbs but the wider it is in an accident the less likely you'll have an arm or leg out there to be caught between it and the terrain.

I'd bet your three sixteenths would be strong enough just as a guess. I have a couple of "T's" I've made that slip into my receiver hitches front and back. I've had three thousand pounds plus up there at speed and not had a problem. They're two inch quarter wall.

Your start looks great. I would consider cutting some of your material into gussets for the inside angles of all your corners.

If you do it the way you've done the other cuts they'll look great and double or triple your strength. The reason I'd use the same material is you have the same impact area if you bump into it or gawd forbid, it bumps into you. And it'd just look slick while doing the job.

When we used to build race car cages we'd sit the driver in the seat and belt him in. Then we'd try to pull and stretch him into a bar. What we wanted was in a crash there'd be no way for him to contact the bar without a failure.

I personally found out that our body will stretch beyond belief. I used to have a helmet that had some damage to prove it.

So you might do a temporary mount and then sit there and walk through your roll over. And then make some adjustments.

I strongly suspect most roll over protection systems on tractors are more for the protection of the manufacturer than they are for the operator.

So you have a great opportunity to do it right. But probably one of the best additions to your ROPS would be a lever coming off the top with a ball on it's end. If you attempt to start the machine without your seat belt on the lever swings down and the ball hits you smack between the eyes. Probably take some cables and pulleys but it could be done.........

 

[DavidInNH]

<font color=red>But probably one of the best additions to your ROPS would be a lever coming off the top with a ball on it's end. If you attempt to start the machine without your seat belt on the lever swings down and the ball hits you smack between the eyes. Probably take some cables and pulleys but it could be done......... </font color=red>/w3tcompact/icons/shocked.gif/w3tcompact/icons/grin.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/clever.gif

 

[micromike]

More excellent suggestions from Harv.

A few years ago my sixteen year old son and a friend of his rolled our jeep cj5. My son's friend had his seat belt on, my son didn't. They hit some black ice on the road and started spinning before hitting a ditch. When the jeep rolled, it threw my son out. He says one minute he was driving down the road and the next he found himself standing in the middle of the road. He said it happened so fast he didn't know what happened, but somehow he landed on his feet on the road.

His friend rolled with the jeep. He was hollering for my son to come help him. When my son got there his friend couldn't get out because...his hand was trapped under the top of the roll bar, which was now in contact with the ground! My son picked up the on the jeep to free his friend. Believe it or not the friends hand was not injured! These were two very very lucky boys.

Moral of the story...wear those seat belts and Harv is right, try to have the rollbar ( if at all possible) far enough away from body parts so that you don't, can't come in contact with them in a roll over.

BTW, nice work!

 

[DavidD]

The seatbelt is my next project, it only makes sense.

Harv, as much as I like your idea on the lever thingy, it may be a while before I get to it......
I am thinking about adding the gussets though and going ahead with a top cover .
My neighbor {a real welder} stopped in tonight and said the squared off front of the top made it look like something from the Flintstones .....{it must be jealousy about my welding skills}
This and a receiver hitch mounted to the top of my bucket are my first welding projects.My neighbor has been playing "Inspector #12" for me, he loves to take his soapstone and write things like undercut, cold lap, and F'd up/ reweld all over my creation.

 

[DavidD]

Fred Flinstone tractor???

 

[Ozarker]

It's looking good David. I have a similar idea for my Yanmar 1500D but haven't started yet.

 

[Soundguy]

Top to bottom strength will probably be less of an issue. The modified arch type structure caries weight well. Failure points or areas of concern / stress may be the welded angles towards the bottom. Side to side strength will depend on the rigidity and cross resistance ( weight will not only be placed on the bracket at the side of the rollover, but will also be transfered throught the horizontal top member to the other bracket. Strength of the tubing, length of the material and geometry of the mounting points will all factor.

If nothing else, it will be good for a sunshade, and a tree branch deflector... better than nothing at all for that purpose.

Soundguy