Technical Dented or kinked frame question .

Hey fellas ,

A question and debate was brought up at work about forklifts and heaven equipment and safety guidelines.

the over head guard ( the roof that protects the operator ) going by safety standards has to be free from dents and damaged welds .

these things are made very similar to a cars frame , boxed rectangular or square tubing and essentially a square with gussets and cross bars for support .

so for this question let’s just say a car with a square or rectangular boxed frame .

now I think a “base ball “ dent in the middle of the frame no creases or kinks and not affecting the corners really does not do much to affect the strength of the frame .

a Kink a sharp dent ( think some one puts a chisel on the frame and bashes it with a hammer)
A nice kink that affects 1 or 2 corners .
To me this is structural and needs to be repaired as if that frame rail gets hit or impacted the spot where the kink is will fold and damage as the corners have been compromised .

some guys where debating depth and how / where where / rust etc etc .


I’m kind of looking for a rule as to when and what type of dent or kink is an automatic “nope” ya gotta fix this .

At this point I got 30 techs on the road who all have there own ideas of “ safety” and of course the government laid out inspection process is as clear and colourful as a foggy morning .

 

This is one of those things that gets close to falling into the same category as the definition of ****ography (You can't explain it, but you know it when you see it.)

As a general rule, sharp edges / kinks that have the potential to cause a stress riser or have significant amounts of yielded material are bad. But where do you draw the line? Obviously it depends on the the application, material type (not all frames are equal), and vehicle use, a**** other considerations. A "baseball" dent in the center of a flat membrane away from any edges would most likely strengthen and stiffen that section. However, what amount of localized strengthening / stiffening leads to problems in other areas as stresses get moved around? Again, it is very application dependent.

These questions are the bain of every structural engineer.

 

Do a drop test onto it to get a p*** or fail. That should clear the fog.

 

I know folks build , grind, weld, box, drill on car frames. It’s done all the time! But, on truck frames, new from the factory, it is painted on most frames, to not cut, weld, or drill on the frames! I know truck frames are somewhat different than car frames, but would be similar to headache racks on a forklift! When I was outfitting new trucks with beds, I never welded nor drilled any truck frame! Just my experiences! Yours may differ!






Bones

 

I would think you need to know what composition the steel is. Mild steel has much better repair properties and or memory than any of the modern high strength and ultra high strength steel used in newer cars. That stuff will crack for sure. Just my opinion based on over 40 years in the Collision Industry.

 

Steel type for a ch***is is the biggest difference on new full frames.
As is manufacturer recommendations.
For older, mild steel frames, you can do just about whatever you want.
New full frames are generally high strength steel. Straightening options are limited. Sharp kinks/buckles are generally non repairable.
Some will allow some heat but heat crayons or monitoring strips must be used.
Repair sections are available for some. Front frame rail sections to replace damaged crush zones and complete rear sections.
Side sway damage will pull, a diamond frame (one side pushed back) is much harder on newer boxed frames with welded x members.

 

Another issue is someone that can straighten it. Frame guys are hard to find. I did tons of frame work both at work and home. I get calls from local shops to pull one every now and then. Sometime they drop em off at school.
But to answer the question, most ch***is are replaced if kinked or have sharp bends.

 

Not sure on steel used .

but I have had my welder repair a bunch for me that have been fubar.

all repairs need to be signed off by an engineer and done by a ticketed welder .

have had many repaired

sometimes the kink can be heated and pulled out

sometime remove the effected section and graft in a new section

some times they want the entire bar replaced

have had very similar kinks repaired and each time the engineer will ask for it to be repaired a different way .

it’s just weird to me that something concerning safety can be so grey .

 

A sharp bend creates a stress concentration which can lead to failure during cyclical loading. It is also in effect creates a "hinge", degrading resistance to impact failure. If you are servicing lift trucks, the OEM should provide guidelines. If anyone thinks damaged overhead cages are fine, ask them to sit inside the unit while weights are piled on.

Our hot rod frames are largely built from mild steel, which is very forgiving to repairs. But think about LSR, NASCAR, circle track and drag ch***is. High strength materials and certified welding are mandatory and sometimes they still kill the driver.

I overheard a body tech in a welding supply shop say that Honda corporate dictates the type and brand of filler wire used to repair certain HSS panels.

 

When dealing with Mercedes-Benz with the G-Wagon for the Canadian military we had many “accident” damaged vehicles both in Canada and in Afghanistan. Their policy (to our horror) was to replace any body panel that was damaged (beyond very simple dents) as they would not warranty their vehicles or the repairs made by anyone else. IMHO we s****ped many vehicles for what I considered light damage. We had several “new” vehicles that had low speed roll overs that only slightly “tilted” the structure above the belt line. However, as far as Mercedes was concerned, the entire body needed to be replaced.

 

High strength steel is fun.
You could rip a mild steel structure apart trying to move the high strength part connected to it 1/4 of an inch.
Most is replaced. It’s not about repairing a vehicle, it’s about energy management in a wreck.
But even if a mild steel structure like a piece of tube is buckled, you’ll have to open it up to repair it.
On a frame bench, welding a pull plate in a buckle was common. Removing a section of a boxed frame to allow access was common.

 

When I worked in factory maintenance, such repairs were often decided by upper management, and usually involved the cheapest possible fix.
The plant manager at one of the forge shops used to run the bra factory, he had no concept of structural integrity, but he was the guy that determined how things got fixed. After a very short while, the maintenance supervisor would present the choices of repairing something with structural integrity, or replacing the item completely with a new version of the old one. The other company I worked for was run by people that were promoted from within, that was much better.
At no time was any repairs determined by a representative of a company we were doing business with, the supervisor would take into account his advice, but the final decision was always made in house.

 

I was a supervisor for a big rig trailer company locally. My dep't ***embled high tensile steel frames, fabricated from flat steel cut parts, then mig welded into structural square tube framing to encapsule our fabricated aluminum tubs, with heavy aluminum bottom gates.
Result? Pair of heavy duty, light weight bottom dumps. Semi trailer and pull trailer total weight: 10,400 lbs.
Problem: Mgmt. denied cracks resultant from denial of oxy-acet. 'normalizing' after welding. I practically begged, but fell on deaf ears.
MY dep't fell to the drilling, repair welding, THEN 'normalizing' faulty weld(s) They never learned, never permitted normalization of welds on HIGH TENSILE STEEL!
Well, I was 'huffy'. (grin) They bellied up in '96, resultant of a 'Top-Heavy' sit.

 

Just as I thought, clear as mud !!

from me , to my techs , to the welder I use to the engineer to YOU guys . There are a 1000 ways to interpret this as safe or not .

I have looked and looked and can find nothing concrete .

 

May contact a structural engineer?

 

Before any repair is done we HAVE to have an engineer look at the damage and state how it needs to be repaired .

I wrote it in a previous post up a bit . I have had similar damage repaired 3-4 different ways after the engineer looked at it .

both me and my welder will look at damage , come up with ways to repair it correctly but have to sit on our hands until the engineer comes to look at it .

and even then it seems like a “ what day of the week , or what kind of mood is the engineer in” is how the repair is decided .

 

Simple. Old mild steel car frames are easy
not a lot of guidelines just get it square. Heat was a normal process to remove damage.
New stuff depends on if it’s high strength steel. Also manufacturers have more stringent repair procedures than decades ago.
Your folk lift top gets recommendations from an engineer.
Car manufacturer recommendations are made by engineers.
Same thing.

 

I used this same system/equipment daily for years
An electronic measuring system combined with pulling equipment and a guy with a hammer

 

Here is old school center line gauges and a floor pulling system

 

Using a tool to reach inside a boxed rail

 

Unless the forklift come supplied with all the steel information and engineering specs or repair procedures in your case I would guess it boils down to a liability issue for the company rather than it actually being repaired to a specific safety spec. If it is not done the same every time then it is not being done to any specific engineered spec but just to a whatever spec that the engineer feels is adequate and is willing to take liability for signing off on.

 

How I grew up fixing frames.
Big I-beam, jacks and hammers.

 

Could you use one of those dentless repair guys with some really big picks ?

Just pokin a little fun at you, but from my experience any time you deal with an engineer, their primary concern is that whatever they reccomend will be something that doesn't come back to bite them personally. Cost is no object !
Our societies fascination with legal repercussions dictates that behaviour.

 

pretty much engineer just left said to me and my welder .

cut this section out , straighten it , reinforce it from the inside then weld it back on .

this is the repair this time , we will see the next one that needs fixing what mood he’s in .

Not really complaint but this whole grey fix it this way or that way , no it’s fine but maybe it’s not simply bugs me .

I would consider this a fail requiring attention .
Not denying that at all

 

Kind of hard to see in the pic but this has a soft dent in it
No creases or kinks but it does have a depression in the middle .

my engineer does not car as to him it’s billable hours and he will OK a fix on anything and everything .


I think this is fine and does not affect the structure

I have some techs who will fail this and deem it to be repaired


I think that’s simply gauging the customer .

 

Sounds like a good way to fix it.

 

With damage like that to a forklift frame I'd question the compentency of the operator.

 

this is nothing , really minor damage to some of the stuff I see .

If it can be completely utterly fubar’d and leave asking WTF happened , leave it to a forklift operator .

some of these guys are absolute artists at warehouse management. And some think they are in a smash up derby .

 

I'm not an engineer by a long shot but would have to believe that on a Forklift cage that kink might end up turning into a crumple point in a more serious crash. Someone where I worked flipped one over with some less than stellar driving and tweaked a few things and the Hyster factory reps came out and went over it and the cage had to be replaced. I just saw the bill and wrote up the paperwork to pay for that one.
After my son totaled his 79 El Camino running straight off into a bar ditch and hitting the other side the wrecker driver who is a long time friend of mine pointed out how the front of the frame crumpled right at the designed in crumple points taking the brunt of the hit. That one folded up but saved his life along with having his seat belt fastened. When I got rear ended by a garbage truck in my box with wheels both ends of it folded up but all four doors will still open without binding up. Neither helicopter crash I wen through had that much impact in the hit.

 

Looks like a Toyota lift?
If you have to meet OSHA guidelines just order new replacements if anything ever happens OSHA will be looking to issue large fines for any repaired guards.
From the fines I've seen you could buy a new lift and it would be cheaper................................
If you repair it, to make it OSHA correct the OEM Manufacturer will have to certify the repair.(This is what I got from the OSHA inspector). We were fined for repaired ROPS, Cuts in solid tires over 1" long, and my favorite OEM seat belts that didn't fit around our larger operators even though they were the ones that toss the extensions in the trash cans everyday..................................