New Project - Centre winch - need help with Stress Analysis

[Hybrid_From_Hell]

With the engine need sorted, I need a new project

In this house if I have "Nothing on" then there is this thing called d e c o r a t i n g or something like that

that raises its head, on that basis, as soon as the engine is finished I have the idea for a centre winch on the 90

Have had this kicking about for ages, I have a centre "Ball" - 4 x Stainless Steel Water pipe 90 degree units, welded together

then cleaned off and rumbled and polished to look like this :

This is about 50mm OD and about 6" width

I want to mount this on the centre of the main hoop like this :

I have been thinking on how to mount this and how to brace it

the forces are going to pull the cage about in ways not designed so will need to support and brace the "Ball"

Enclosed below are some pictures of the cage - same as mine) which I fitted to John Bs Trayback, this show

quite clearly the "X" on the main hioop, and the same "X" of the roof bars, I have outlined some thoughts re fitting

and I would like those who know (Hellloooooooooooooo Sir Bish ) to give me feedback on the 4 x options, and

if they think better, how they would do it please

From the top pick downwards

Top Pic - 2 x "Roll cage" type tubes, fishmouthed etc and welded into front of ball to cage, rear of ball having

a thick (say 6mm) "Shpaed plate" welded to the back of the ball and the front edge of the main hoop

Pic 2 - Below 2 x roll cage type tubes welded down tho cross brace tubes within hoop

Pic 3 Ball welded into big thick shaped plate seam welded to X on roof and front edge of top hoop

maybe also have the left and right "Edges" foled downwards to increase plate strength ?

Pic 4 (Bottom) single roll cage type tube top hoop to cross point in X in Main hoop

It will be a Goldfish winch, and the mounting at the base was sort of sorted when I did the main cage work, the mounting

for the winch connects to the sides of the feet of the rollcage, and through to underneath where the mountings tie into

the main chassis rails, so thats sorted, Plasma will run from top of winch 'up' and through ball, its this top bit I am uncertain how to

progress

So, thoughts please all

Nige

[Hybrid_From_Hell]

Calling Sir Bish of Boshville ......

[FridgeFreezer]

Stupid question: How does a winch on the roof help in most situations? Surely half the time it'll either be trying to push you deeper into the mud or roll the truck in the direction of travel?

Shiny ring though

[CwazyWabbit]

Stupid question: How does a winch on the roof help in most situations? Surely half the time it'll either be trying to push you deeper into the mud or roll the truck in the direction of travel?

Shiny ring though

They can be useful traversing a sideslope where the angle is too great.

[landroversforever]

Useful for changing tyres and reseating springs!

Personally Nige, I prefer the ones which hang off the back of the tube, with two braces back down to the X in the rear hoop.

Have a look at this thread nige, may be useful: http://forums.lr4x4.com/index.php?showtopic=66181

[zim]

Nige,

You will bend your cage down if you mount your doughnut there. So will need a vertical brace.

Here is how i've braced and fitted mine.

We have not bent it (yet) and it's had a lot of abuse. Some serious pulls on it when we've been without hydraulics for some reason and we're using the centre as a rear winch.

Just to give you an idea, my centre winch is a TDS9.5 with a bow 2 - so not exactly a small one

G

Edit : I clicked the link above and left it opening in another window whilst i wrote this reply ! doh !

[bishbosh]

Nige,

It is all about triangles as usual. Zim's solution is what I would have recommended. Two straight tubes to existing nodes of the cage. You don't want tubes joining into an existing tube part way along its length.

Due to the eccentricity of the doughnut the vertical tube will experience a lot of bending so if you can gusset the vertical tube to the horizontal tube you add in to the roof that will help a lot. Depends how much room you have between the roof and the cage.

Zim's stiffeners are also very important. I would try and get them as far down the tube as you can (within reason) to add as much strength to the tube as possible.

HTH

[Hybrid_From_Hell]

Hmmmmm so glad I asked

OK, taken on board and sort of petty much understood.

So, I want the "Ball" to be the cab side of the main hoop, not as per Zims on the outside.

So, taking whats been said, hows about this idea ?

Pic 1 (top)

Can't do a straight line to the roof X as the ball would be blocked, so a Y shaped with 2 x tubes either side

of the Ball, joining at the front of the ball into 1 x Tube to X on roof.

On top of the Y shaped tubes a Lump of Plate seam welded to tubes and main hoop

Pic 2

The Y tube also gussetted at the X join at the roof.

The downward tube to X join on main cage single tube, then 2 x tubes

Going from the front edge of the ball, down just off vertical joining to the down tube, with gussets ?

Tricky to draw, but hope it makes sense ?

Thoughts again please all ?

Nige

[Nigelw]

it would be the same, but you do not have the longitudinal from front to rear hoop and you have more space between yr rear hoop and the back of your cab, would suggest strengthening tube vertically to hoop at donut and base plate for it to be stiffened up as per the one pictured, wondering what types of actual load you will put on it I would be tempted to add another diagonal cross brace to stiffen the hoop a little more, wouldn't want unexpected shock loading to buckle the hoop!!!

[Hybrid_From_Hell]

My little mind has melted a tad

Any chance of a piccie / back of fag packet doodle ?

Nige

[landroversforever]

Nige, what's the reason for putting the ring on the inside of the cage rather than the back? Have you got the winch mount on the cab side of the hoop?

[Hybrid_From_Hell]

Yup

Winch will mount on the inside of the cage (ie between inside of cage and bulkhead) so plasma

would be a vertical fit to the ball

Nige

[zim]

so do the same as mine - but on the inside.

?

[Hybrid_From_Hell]

Aye - except can't do single tube as ball entry exit would be

Blocked - hence me question on Y piece

Any chance you could post up some extra pics

Of yer gussets mr :0)

Nige

[zim]

Ah ok.

I don't think i've got any other pics online, and i'm away at sea at the moment.

But the gussets aren't complex. Just a couple pieces of 6mm plate that we've bent to shape and then welded in. Th top plate that the gussets mate up to from below and the doughnut mounts to from above is probably the same or 8mm ( i can't remember!).

Devon 4x4 do a similar sort of thing (ish). But not as braced as ours i don't think.

Edit :

http://www.devon4x4.com/index.php?page=shop.product_details&flypage=flypage_new.tpl&category_id=1012962&product_id=1901&option=com_virtuemart&Itemid=14

[Team Idris]

A cab side winch led me to 2 tubes, which line up nicely with Malcolms W rope hoop. But given the way you are laid out, the above part joined to the roof X with a single tube sounds best

In the unlikely event I ever made it to a third winch, I laid it out so that the top winch will run to the back rollers if my main rear winch failed.

I see folks do good stuff with loops on the top corners as well?

The 80's bolwer design took me a different way to this place;

I recon if the msa say no to combined roll cage/winch points later on, I'm part way there.

[steve200TDi]

Hi,

Something like this:

So the doughnut forms part of the structure and the tube from the winch hawes goes to the cross in the roof and a tube from the cross in the rear hoop up to the roof tube.

Basically what has been suggested I think.

All depends if you want the doughnut in line with all the tubework or like Zim's where it's bolted or welded to a flat plate.

Steve (Might need to add one to the TD5 build!)

[Hybrid_From_Hell]

^^^

I Like that - a lot

Nige

[Daan]

i dont like that if Im honest .

The good old gravity just puls to hard on that thing, so high up. I wouldn't do any reinforcement, instead go to the corners and have loop between each backstay and the mainhoop. minimum material added. Speaking of weight, I wouldn't even bother with a third winch. Just use the rear winch with an extra roller to allow it being used in this way. 25 kg for a goldfish I reckon, just leave it at home.

Plenty of people have done it this way and make do with two winches.

I'm just not getting the I have more winches than you thing.

But I No nothink.....

Daan

[Steve Hiatt]

What is a winch anyway?

[Daan]

What is a winch anyway?

The device you use to pull the remains of your car on a transporter once you retire....

Daan

[landroversforever]

What is a winch anyway?

Its a bit like a wench, but is dirtier and doesn't mind what it pulls.

[bishbosh]

Daan does have a point, but if you are set on this path then you need to think that the doughnut will put bending forces into both the horizontal roof tube(s) and the vertical B hoop tube. This is a bad thing. So, to remedy this you need to make the tubes stronger in bending. This is best achieved with gussets (or stiffeners) that are welded along the length of the tube rather than a tube just coming in to a single point.

If you post up some side on shots showing the space between the B hoop and the cab I will try and scribble on them to show what I mean.

[Hybrid_From_Hell]

will do Sir Bishness

N

[zim]

i dont like that if Im honest .

The good old gravity just puls to hard on that thing, so high up. I wouldn't do any reinforcement, instead go to the corners and have loop between each backstay and the mainhoop. minimum material added. Speaking of weight, I wouldn't even bother with a third winch. Just use the rear winch with an extra roller to allow it being used in this way. 25 kg for a goldfish I reckon, just leave it at home.

Plenty of people have done it this way and make do with two winches.

I'm just not getting the I have more winches than you thing.

But I No nothink.....

Daan

Daan, i disagree with two things above.....

1) we tried the whole loop on each side. it's a pain in the butt to be perfectly honest. having to constantly re-route the rope is more hassle than it's worth. We also found that if the winch was attached onto an anchor point then you moved to another position, you might find that you want it now to be on the other hoop....too late to do now as you're suspended on it already.

you also find, that you generally have to attach the centre winch when you've gone past the point of no return - this is not when you want to start fannying about re-routing.

2) afaik Nige has hydraulic milemarker winches....these are no good when upside down and the engine isn't running. (i'm in the same situation)

we have at some points used the centre as a front winch either to help the front winch or to help level the vehicle when going up a steep bank - can be used to maintain oil pressure not sure if Nige would hang his vehicle at these sorts of angles but we do. remember if you loose oil pressure and shut down the engine and electric winch is useful.

G