winch bumper build

[octo0072000]

I used to be a licenced rally recovery unit and spectators used to get quite stroppy when I moved them out of the danger areas while I was winching, some photographers thought their official tabard made them invulnerable

i know exactly what you mean had to escort a few it won't happen to me off site

 

[ned]

First off, appreciate the interest and the info, will take all the pointers i can get.

Second, I reckon a re-evaluation is in order, the magnitude of which I'm not sure about yet. I dont want to add too much weight. If I'm to add a camper to the back i have to keep it under 3.5 tons, and this thing is already up around 100kg including the winch.
Skotl you guessed correct, the truck weighs 2 tons. I reckon some thicker uprights would be a good idea, Im not sure the ones i have are heavy enough.

Third, its not a bumper mount. These protrude from the bumper and are specifically for attachments.

There are bolt holes in the cross-member bracket shown below, that I can use to add strength.

 

[skotl]

I don't understand what your arrows are pointing at. The winch tray/bumper needs to be attached to the chassis rails - is that not the "tubes"?

I doubt that the hanging plates would appreciate having a five ton pull put on them from any angle...

 

[ned]

I was thinking something like this would make them stronger

sorry im using MS paint here, please forgive the godawful drawings. I could also brace it like so from the holes at the crossmember, dunno will this traslate

 

[skotl]

Are these the chassis rails at the back/underneath, then? That would make more sense.
Someone with more vehicle knowledge than me would need to say what the round tube is and kind of stress it's able to take.

You're not going to want too much extra length on the rails (not the length of the drawing you have in black) - is there any chance of mounting the winch tray underneath, closer to the rails?

BTW some folk fit winches at the back of the truck as you get easier access to the rails without the engine and turney bits getting in the way!

 

[Robotstar5]

BTW some folk fit winches at the back of the truck as you get easier access to the rails without the engine and turney bits getting in the way!

and it's easier to pull yourself out if you've just driven into trouble, you don't want to winch yourself further into it

 

[octo0072000]

the one picture with the black in the picture would be better than the crossing idea
skoti the round tubes are the chassis legs

 

[ned]

yep, thats correct. The rear mount is an idea, but, its going on the front.
Just gotta figure out where to get heavier plate or channel for the uprights, without spending a ridiculous amount on steel.
There is a stockholders local to me but I dont want to buy a 7 meter length just for 2 feet of steel.

 

[skotl]

Ahhhh! Now I see - the view from the rear is better than the view from the front

Yep - they should be strong enough to take the tray, then run some bracing back to the other rails, and lots of cross-bracing!

 

[clift_d]

If it was me I would probably be thinking about beefing up and deepening that front crossmember - where the towing eye used to be attached, and then mounting the winch on the face of that. It's obviously been considered strong enough to take towing loads otherwise the towing eye wouldn't have been fixed there. Then I would build the bumper around in front of it to protect / encase it, with the fairlead through the front centre panel and a couple of towing eyes onto the ends of those tubular chassis members. That's what I think but I'm happy to be contradicted.

 

[slim_boy_fat]

....I don' t want to buy a 7 meter length just for 2 feet of steel

No fabrication place(s) near at hand with a skip......?

 

[ned]

I was looking online and that's what others have done Cliff. Pics are few and far between of this truck with winches, but any ive seen have that done.

but it looks crap. and what it looks like is important to me.


i had a look at what steel i have, i have enough 10mm plate to recreate the uprights in 10mm. If i did that, and braced it like the black drawing above, that would be strong enough. The bolts would give first, or the chassis would bend. But the 10mm plate will hardly buckle or deform.
Anyone care to disagree? Its going to be a pain in the neck cutting it and drilling it.


I also have heavier 8mm material I could use for the mount plate, but there is no bend in it to add stiffness.
What i could do, is score it with the 9 inch grinder, to create a fold in it, and then weld in the scored bit.

 

[colnerov]

Hi, Be careful, those towing eyes as you call them might not be towing eyes but lashing eyes, used to secure the vehicle when being transported. I would be inclined to have a new crossmember 'U' bolted to the chassis rail behind the first crossmember and then work forward from that possibly with another in front to give an independent stable platform.

Colin

 

[skotl]

Colin's right - these eyes are probably designed for half a ton stress at most.

I'm not convinced about scoring the plate, bending it, and welding in to the V - I'm not an metallurgics expert but I can't see that being anything other than weaker than the original plate. How about making a 90 degree join with side braces (and probably angled / cross braces)? Having wrote that, I guess doing what you suggest with side&angle braces wouldn't be any worse than my suggestion.

Apologies if I keep coming over as the voice of doom, but these kinds of stresses/loads aren't trifling.

 

[clift_d]

You can easily exceed 1.5 or 2 times vehicle weight dependent on conditions - there's a good write up of why on pirate4x4 here - see the section on Calculating the force of a recovery operation. From that article:

If you've got a vehicle which is at least 3.5 ton then you could easily have a pulling load on your winch mount of 7 tons or beyond.

 

[ned]

okay, so i went to the cinema and spent most the cinema building this in my head. I'll need a plasma cutter and I dont have one.

your right about scoring it, I'll pay to bend it with a press brake

photoshop is superior to ms paint. Yah the back of it had a lot of cleaning / painting

 

[colnerov]

You can easily exceed 1.5 or 2 times vehicle weight dependent on conditions - there's a good write up of why on pirate4x4 here - see the section on Calculating the force of a recovery operation. From that article:

If you've got a vehicle which is at least 3.5 ton then you could easily have a pulling load on your winch mount of 7 tons or beyond.

Hi, I've seen and used those for a recovery. Once you know load you rig it so you don't exceed the capacity of the winch (and its mount).

Colin

 

[skotl]

okay, so i went to the cinema and spent most the cinema building this in my head. I'll need a plasma cutter and I dont have one.

your right about scoring it, I'll pay to bend it with a press brake

photoshop is superior to ms paint. Yah the back of it had a lot of cleaning / painting

And cross-brace it, with angles between each of the corners.

 

[zx9]

Quite aside from safety considerations I would be trying to tuck the winch closer into the chassis, the mk1 version looks to use up a lot of the arrival angle. The massive arrival and departure angles are some of the Unimog USPs.

 

[knighty]

why not put a flat plate straight across the ends of the tube chassis

and then turn the winch 90' so it bolts straight to that ? (bolts backwards instead of down)

then with your 2 braces going back to those other mounting plates (the square ones coming down from the chassis) you'll stop any vertical twist


the plate will be taller than the tube, so you could weld 2 pieces to the back of the plate, one just above and one just below the tube... so looking side on at the plate it would look like a U shape turned 90' ?
(these bits could be joined into the bracing going backwards to those other points)