Roll Cages

[northernchris]

That is basicly what I said

unless good quality means somthing else

yep u did say that but my coment was at astro-al !!!!!!!

[Astro_Al]

And your point is?????????

I think it's pretty clear.

Let's not drag this out - this is a great thread. My point was that H_F_H posted a shed load of great tech info with piccies and everything, including modes of failure, regulations, design principles, methods of 'good practice' etc etc. That's all. Your post was not 'the same thing but in less words'. No. It was however, I agree, less words.

Enough. Let's get back on track. Now I do have a relevant Q if someone could help out here. I genuinely believed that cages were not designed as crumple zones, but effectively as safety cells, which provide a solid 3D volume for the occupants regardless of the turmoil occurring all around. I really don't want to be squished in a crumple-able cage just to slow down the rate of deceleration.

This is why you always hear people talking of reinforcement and making things bigger and stronger - not designing in failure modes to absorb a specific amount of kinetic energy or whatever.

Now what did I miss? Which is it? Do people consider this stuff (I thought not), and if so, how do they incorporate this into the design? Or is it not the case that they are designed to absorb energy by plastic deformation?

Cheers, Al.

Edited November 17, 2005 by Astro_Al

[Daan]

I have been involved in design of roll cages on a professional basis for quite some time, starting with Safety Devices. I was actually working there when jules freelander was prepared.

I tried to incorporate some of the ideas of motorsport into my Landrover cage, which I built myself. In motorsport the cage is mainly there for torsional rigidity and also safety. The weight is much more important in motorsport.

I agree with most of what has been said here, but a few additions:

The front defender rigger I used with no reinforcement, only a bracket welded on the end to mount the front cage. The rear internal cage has a cross, this is vital. Also triangulation in the roof section. The cage with backstays is fitted on the wheelboxes, and extended to the chassis. I welded the Main cage mount to the chassis, please donot use exhaust clamps for this, they are called exhaust clamps for a reason! The backstays are fitted to a heavy duty rear crossmember. The standard crossmember is not strong enough I believe. The comment about mounts needing to be strong I agree with, but the 6 mm spreader plates do bring tears to my eyes. Our chassis is only 2 mm so what are we trying to achieve here?

Also, the least amount of bends, I had a main hoop bend up and the LH and RH a-hoop, the rest straights.

Straight pipe is easyer and stronger; Whenever you bend the tube weakens.

I used T45 chromoly, aircraft spec material, this is double the strength and allows you to build much lighter. The fixing brackets are the same material, just make sure the bolts are very close to the tube, the strength will be enormous.

The ARC rules are desperately over the top, but they allow you to build a cage from low grade material (like seamed tube) and make it still save.

So does it work? Well, I rolled it recently (on its roof 3 times) and the rh top corner of the cage moved (see pic). The rest of the cage has not moved at all. It landed on a rock first, this is were the cage buckled.

I believe the cage passed for Challenge event competition.

DaanMy Webpage

[Daan]

piccy.

[northernchris]

Atro-al

What is it you do for a living????????? I just wonderd because it sounds like you should start a cage making firm or are you all CHAT.Anyone can QUOTE carp from a book or what they have heard,me on the other hand i go with what i know is right and correct and have learned over the years DOING the JOB not chatting about it.... Anyways nice weather.

Chris

[Les Brock]

Atro-al

What is it you do for a living????????? I just wonderd because it sounds like you should start a cage making firm or are you all CHAT.Anyone can QUOTE carp from a book or what they have heard,me on the other hand i go with what i know is right and correct and have learned over the years DOING the JOB not chatting about it.... Anyways nice weather.

Chris

Blimey it aint Rocket Science.....

[Astro_Al]

Atro-al

What is it you do for a living????????? I just wonderd because it sounds like you should start a cage making firm or are you all CHAT.Anyone can QUOTE carp from a book or what they have heard,me on the other hand i go with what i know is right and correct and have learned over the years DOING the JOB not chatting about it.... Anyways nice weather.

Chris

Er... ok... a-n-d breathe...

I'm not quoting anything - not sure I'm with you?

I really don't want an argument - I just asked whether or not cages are designed as or with crumple zones - as you said, which is something I've never heard of before (and since I'm about to build a cage - yes, my first one - i'm interested), or if they are meant to be safety cell type devices. Both of which kind of make sense intuitively, but I think I'd prefer the latter... Wouldn't you?

Since this is a forum where we discuss topics like this, saying it's all chat is a bit, er... oh, I don't know... dumb?

You came out with something I'd never heard before so I was intruiged, and no it's not my job, obviously, but at no point have I said I know what I'm on about - HENCE THE QUESTION.

>"me on the other hand i go with what i know is right and correct and have learned over the years DOING the JOB not chatting about it.... Anyways nice weather."

Well, for someone so keen on getting on with it and not chatting you're sure talking a lot...?

Now, stick to the tech. Please. Maybe you could even answer my question?

Les - I nearly wrote 'it's not brain surgery'...

Al.

Edited November 17, 2005 by Astro_Al

[series3_mad]

piccy.

ouch

I see why you used that aircraft material, pretty strong by the looks of it apart from some bits.

Edited February 7, 2007 by white90

[northernchris]

Astro-al

The cages that we fitted to the subaru world rally cars was to do two jobs

First was to protect the driver/co-driver

Second was to enhance the dynamic performace of the car

The cage is made so it deforms in a predictable manner ,disapating the energy through/around the car.The perpose of a cage on a winch challange motor is abit different it needs to be able to take knocks/scraps without moving to protect the body work this is why some people go for the bigger O/D tubeing.This is ok because the impact speeds involved in trials/challange motors is far slower.These are my own thoughts on the subject.

Regards Chris

[LR90]

This is turning out to be a great thread but looks to me like we're all discussing how the cage should be constructed/mounted but are all trying to achieve different goals?

If I just wanted something to protect my truck from trees (ie reduce panel damage) then I would seriously consider the bolt on cage shown earlier. Yep, not as good for a major roll but as a home bolt on job to protect the panels and no welding. Winner.

Others want a bit more protection in the event of a roll but ALSO want to protect the panels. So, you get the exo cage common on challenge events, well constructed and mounted to give good degree of saftey in a big roll but often also quite rigid as well as deformation of the cage might lead to panel damage (and cage repair) and this is really meant as a big, heavy fit once and not buy again type of protection.

Alternatively (and I've not seen it mentioned yet though I see Chris has put some pics in the gallery) are the fully internal cages. These are clearly not going to protect the panels so safety comes to the for. If you roll your truck big time its going to be expensive and cage replacement might well be an added acceptable option. this can result in lighter cages (to reduce vehicel weight) but which are desing to deform to increase drive safety.

No one cage can meet all these objectives (seen guys on P4x4 with internal AND external cages) and what might be considered a bad design feature in one scenario could be what makes that design more suitable for another application.

So consider first what you want to achieve and select your design/construction accordingly.

[Astro_Al]

Ok, great. Thanks for the info.

I'm still very interested in how you go about designing a cage which deforms in a predictable manner - just for my own interest, obviously I think this is overkill for my cage.

Any further input gratefully received.

Al.

[Hybrid_From_Hell]

OK

ALL cages will deform - period.

Rally cars etc also have cages to stiffen up the body from flexing, also some cars (when I rallied years ago) have bodies seam welded to add strength etc and stop flex etc...LR have a ladder chassis so in this respect it sort of does the job for us !

Any cages ..............

They will ALL deform dependant on :

the forces that hit,

the type of load (ie sreadout - landing on roof - or concentrated - landing on one edge of roff from rolling)

Type of material used / thickness ID OD

And construction (double cross vs no crosss etc etc)

For off road use there are mainly 2 types of cage

Type 1. (some ...or all may apply)

Some cage is better than no cage / Not built to a comp spec standard / designed for somesaftey / body protection / Bling (seriously some have them just for this !)

Tend to use smaller OD tube (keeps costs down easier to bend etc etc SD are or where kings at this - the 90 / 110 cage was a (I THINK) CNC produced cage, bolt together and was stated as not siutable for competetion etc.#

This is NOT to say the cage is rubbish - it is not, given a prefereance to a roll in eiter a 90 with nothing or a SD cage - no contest, but it has its drawbacks.

Tube - bit small on the OD and bit thin on the ID, mountings are a bit mickey mouse, no cross brace, and the chassis mounts and bolt through wing to front cage are suspect, .........but it is NOT rubbish.

On the issue of mounting @ 6mm on a 2mm chassis see point 2 below, but the logic is that I think the plates are someth8ing like 6 inches square welded to the top of the chassis and then same to the bottom of the cage etc then 4x bolt, this spreads the point on load from the 48,, tube bearing down....OTT ? Maybe ....

You could not enter a comp safari with it - but frankly thats not whats its designed for......

Type 2. (all apply)

Competetion - full stop.

Here you HAVE to adhere to the specs of the governing bodies, like them or not. PERIOD.

These cages are possibly OTT, Heavy, and complex, but its what the rules state. In a BIG OFF these will give you the best chance of survival......and yes they will still colapse.......

Type 3. (me)

Most of Type 2, but modified to give me a better working cage for practicallity, ie my cage would pass scriutineering on ALL areas EXCEPT the down bars at the back, this is due to me fitting them further out and having them virtually touch the sides, twaeked so I have full access to the rear loasdspace, I KNOW this has reduced the strength, so I have a extra FULL hoop at the back with to additional top bars on the roof joining them together, ie in the rear tub I have 2x full hoops, chassis mounted and 4 bars 2x to the chassis from the front hoop (non MSA styley) and 2x roof level ...even with all this "ERxtra" its not going to pass....it IS however dead easy for me to make legal shoulsd I need to...other than that I know the cgae will take some serious abuse....

OH, and the rear section took me 8.00am to 8.00pm 6 days, the front with Jon Ws help 4 days to do 2, and then another 2 days to do the mounts to the chassis at the rear and 2 days for the roof bars to join to the rear hoop....thats approx 14 days work........thats why good cages do cost money, yep they have extar equipement and mutlipe people, but it is VERY man hout hungry work !

If the cage seems cheap, or too good a value to be true - it probably is...

Hope this helps, and doesn't wind anyone up !

Nige.

PS Daan

T45

Jeeez you have to much money (or is that none !) VERY NIce.

The roll you have is one I would not like, and it testament to the cage, it did exactly what it was designed to do, and your still here, guess it made both a mess of the cage / LR / And Underpants ?

Edited February 15, 2007 by Hybrid_From_Hell

[Daan]

Nige,

Agreed with your points, as I said, the rules allow you to use bad material and still end up with a strong cage.

About the T45: Expensive, but I used about half the amount that you did and less volume of material, I paid about 350 pounds on tube. Safety devices did the bending to my drawings using their CNC bender. I still have the drawings so I can have a new leg bend up from that to repair the cage.

The damage on the picture is all the damage there was on the cage. The damage on bodywork, pride and underwear considerably more!

Daan

[northernchris]

nige

The cage in the pics looks well put together,what tubing did you use dia type etc? You are right in the fact that cage work is VERY labour intesive. When i am bending tube i normaly bend 5 or six of the same bend so i have stock built up,the only thing i dont do is scolop the ends i wait until i fit them till i do that.Out of interest what did you use to profile your tube ends,i just renewd our machine for profileing i makes light work of the fish mouths.

Chris

Edited November 17, 2005 by northernchris

[northernchris]

Daan

Have you got the vid of you rolling for us to look at?

Chris

[Hybrid_From_Hell]

Perv

Er...yeah actaully I'd like to see it too, move over, pervs only on this bench eh Chris ?

Tube is a combination Of CDS and 48.3mm BS1387 tubing, Corus was the manufactuer, decent quality, and bent nicely, CDS was a PITFA !

To fishmouth, belive it or not is was a combination of a 48mm holesaw. mounted into a 1950s BIG milling Machine (my neighbour said having a 3 ton mill in a garage in a semi was a HOCC - Hobby Out Of Control B) , which as a 2 axis compund head...

50 RPM fliud and time did really nice cuts, cept when it got mixed up and expoloded the cutter making john & I jump about 6 foot in the air and panic !...then fit new cutter ...........

Boy its got some grunt !....then it was Mr A Grinder and his mates the Files.............

Re your comments about making 5 or 6 bends on the same tubework, so did we, but the main difference was with us the 1st 4 or 5 wrong, it really was like "The 3 Bears Engineering Co Inc" 1st too small, second too big, and the 3 /4 /5 just right

Rush...........................and you are Scr^wed .....do it for a living ?........do you take tablets we had had quite enough after 4 days...........glad to get back to work !

Nige

Edited February 15, 2007 by Hybrid_From_Hell

[northernchris]

Yep hard work,but well worth it.

Chris

[white90]

Making the roll cages for Jon Whites (much modified Series) and my 90...

I had a 50th Cage on the 90 that I bought and fitted,

I was never really happy from day 1 with it, lovely as it is ....for really serious competition it was not up to the job, .....partly as I have a reputation for engineering OTT, .....and partly as I also wnated to have a full cage connected to the internal rear cage (7 days previous work) which matched and was to the same 'OTT' standard

JW expressed a interest in a front hoop too, ....

so make 1 on my own.... or 2 with his help....so 2 it was...

We started this some long while ago,...............

I gave up trying to find any company that would do exactly what we wanted, ....they all started by saying "No problem" they all ended by basically saying they didn't want the work / hassle.

the problem was we knew exactly what we wanted.

Cages absolutely symetrical

Cages as close to the bodywork as possible

Net result was a defeaning silence from all enquires

The next idea we had was to see if we could save time by having the main hoops bent up...... loads of phone calls resulted in me ordering 2x front roll hoops from a 'well known' 4x4 supplier,.... he assured us that these were 'Manderel bent' and 'off a jig' etc etc, we would be "Chuufed" and "delighted with them"

Ordered 2, ......and TNT van duly arrived, ....unloaded them, .......phoned matey and said how sorry I was that the expert tube bender they had had left their employ - ......and that the 2 'POS' delivered were on there way back

1. They did not match

2. the tube showed huge wall failure on the inside radius.

Refund granted

Back to square 1

So JW and I obtained enough tube to run a gas line to Saudi.

A weekend later we had main hoop tubes, but it was sometome (until now) that we planned time to sort.

I took of Wends Thursday and Friday to make up the mounts, plugs for base (huge 1 inch welded bungs with M12 threads for a upwards bolt for mounting through the 6mm base plate etc etc etc :

A pair of these were made up, all 6mm plate extended and welded onto the chassis for the cage,

Jon had already done his so I was in 'catch up', .....unbelivabily 'day 1' was remove wings and bits from landy,. make this one mount, the next day make the other side...Jeez, fabrication times !

So, saturday came, .....we grabbed the previous bent hoops and in short time we had in on mine and johns and looking good Jon said for me not to be so fussy as I was flashing around with a tape measure and to just shove his on and not pratt about :

both cages are to be removable, this is via two machined tubes welded to the chassis with huge cross bolting through them :

these are machined from CDS and are about 5mm wall !

This was good as it saved hours ,I did adjust so it then looked like this :

It was going well, this was the end of day 1, sunday we regrouped and did the side bars :

We were both agreed, as close to bodywork as possible, .....

prob was if you look closely I had "Modified" my Passenger side roof massively, whereas Jon has "Modified" his entire roof "Massively", .....but we got there in the end with some carefull measuring :

As we said - close to bodywork

and as such was eventuially ok, as for the outer side bars both of us had nightmares, these have complex compound bends at each end and to get them right we had a few (ok ok a load) of trail "Attempts" before we cracked it...

Mine was more work as I wanted a cross bar, (may still do the other one the other way, still unsure ....) for triangulation when things go "Horribly wrong" .....JW decided he didn't and thats its more than strong enough, he's prob right, ...........and I am not in any hurry to disprove him

but I shoved a cross bar in (from drivers head to passenger front) :

Having let them dry (we both had stacks to do), all that remained was to 'simply reattach' painted cages :

JWs and mine :

er, ok own up time....

Having welded in the inner cross bar things seem to have tightened up on reassembly, my bolt holes were now out by about 3-4mm, so we had to resort to a "Tweak" JWs M8000 on my cage pulling the bars into alignment !!

Made the neigbours twitch as to WTF was going on

and then my Wifey returned ......and brought us both a cold Guiness out...... and took photos :

So, what did you all get up to on the Bank Hols ?

Nige & Jon

[jules]

Astro-al

The cages that we fitted to the subaru world rally cars was to do two jobs

First was to protect the driver/co-driver

Second was to enhance the dynamic performace of the car

The cage is made so it deforms in a predictable manner ,disapating the energy through/around the car.The perpose of a cage on a winch challange motor is abit different it needs to be able to take knocks/scraps without moving to protect the body work this is why some people go for the bigger O/D tubeing.This is ok because the impact speeds involved in trials/challange motors is far slower.These are my own thoughts on the subject.

Regards Chris

This are my feelings on the subject also.

Chris

What the story with the new regs on the extra braces I need fitting the mine and the wife cars for next season as I will be doing some rallies as well as the British Off Road championships both cars have the SD race cage the Ex Dakar one has the (French) FIA extra windscreen brace on to of the dash. both will need the top of screen to door rail brace.

Julian

[northernchris]

This are my feelings on the subject also.

Chris

What the story with the new regs on the extra braces I need fitting the mine and the wife cars for next season as I will be doing some rallies as well as the British Off Road championships both cars have the SD race cage the Ex Dakar one has the (French) FIA extra windscreen brace on to of the dash. both will need the top of screen to door rail brace.

Julian

Jules i am in talks with the msa at the mo trying to find out what is in store for the next TWO years so we can get new tooling in if need be.What have you seen/been told.

Chris

[jules]

Jules i am in talks with the msa at the mo trying to find out what is in store for the next TWO years so we can get new tooling in if need be.What have you seen/been told.

Chris

I'm a bit sketchy

That why I was asking

I have been told that its coming in but not when I don't fancy turning up for a meeting be being told I can't race due to my cage is out of date. I was watching the WRC on ITV and you can see on the WRC scuby that there is a extra cage brace like a quater light in the cage next to the driver and co-driver. I assum this is the new brace. Robbo did not tel us anything about it but I will have a look at the Auto Sport Show in jan to see whats new. My main worry is that the cage will have to be hacked about to weld in the new section and it will look a mess. I will be well Mildly miffed if it meens a new cage for both cars.

Julian

[northernchris]

I'm a bit sketchy

That why I was asking

I have been told that its coming in but not when I don't fancy turning up for a meeting be being told I can't race due to my cage is out of date. I was watching the WRC on ITV and you can see on the WRC scuby that there is a extra cage brace like a quater light in the cage next to the driver and co-driver. I assum this is the new brace. Robbo did not tel us anything about it but I will have a look at the Auto Sport Show in jan to see whats new. My main worry is that the cage will have to be hacked about to weld in the new section and it will look a mess. I will be well Mildly miffed if it meens a new cage for both cars.

Julian

Can you send me a pic of the cage jules?

[Daan]

Chris, have a look here:

http://www.olrg.org.uk/daan_off/index.html

Daan

[northernchris]

Chris, have a look here:

http://www.olrg.org.uk/daan_off/index.html

Daan

Cage did its job well daan! Wat dia tube did you use?

[series3_mad]

Nige.

Wat was the lenghts for the whole front hoop and all the lengths such middle surport half way up the front hoop and for the bits on the roof.