Some further testing on my trailer

[tonyw]

If y'all remember a previous thread about my trailer build, which ended in the sages condemning the structural integrity of the trailer and advising me to start over with a better design. Realizing that they knew more about this than I did, I was going to take the thing apart and start over. But I hated to destroy all that work without really know how much my little trailer would hold. It would be best to see her going down fighting, right? And that is what I did. The sages said the point that was dangerously unsafe was the connection point between the gooseneck and the trailer frame. So I tested that point. See the pics below.

 

So what do you think? I am not saying the sages are wrong, but there's probably a 1,000 lbs on that hitch and it didn't break. Tonight I am going to put another piece on it. I still am thinking about rebuilding, even though this one is holding up well. The last picture is the connection point between the gooseneck and trailer--the piece thought to be the weakest.

Edited June 26, 2015 by tonyw
clarification

[Charles R. Stevens]

1000# static is not 1000# dinnamic. Not saying you cant make it work, (with enugh thrust you can make a brick fly, just look at the F4) but hitting a few hundred pot holes at 50 miles an hour or the cazy bumpity bumpity of a cement hyway at 65 mph for a few thiusand cycles can crack welds, fatige members and play havic. The next logical test is to tow it and see how it holds up. Be aware that it may hold up, may bend, may crack or may fail in a catastrafic maner.  

[HWooldridge]

+1 to what Charles said.  A static load failure will typically be higher than a dynamic one, which is why some manufactured items are cycle tested under real world conditions rather than simply applying load once (although load data is also useful information).

[Frosty]

Anything can be MADE to work. As already said a static load is entirely different than a live(dynamic) load. Two 2"x6" on edge will support a 1,000lb static load over a 8' span. How many 4" drops do you think it'd survive?

If you aren't going to take that trailer on public roads it's a what the hey, you're only risking your own health and welfare. However, it is not only irresponsible to take that on public roads, it's a screaming liability. ANY accident involving it will be deemed your fault.

Above and beyond legal liability, will you be able to look yourself in the mirror if you hurt someone else? How about a Subaru full of children? Taking that abortion on a public road is literally criminal. Id be surprised if you got past the first cop that got a good look at it.

Frosty the Lucky.

[arftist]

http://www.polytechnichub.com/fundamental-concepts-principle-applied-mechanics/

 

I was very fortunate to inherit an old textbook called "Applied Mechanics and Heat". It was an outline of simple laws of physics. I long ago lost it and was never able to find even a remotely similar book however, if you start at the above and keep delving, you will eventually find what you need to know, such things as leverage, triangulation, etc. 

Above all, remember the message that has been given; when creating objects which could inflict injuries upon others (and of course yourself) you have a moral obligation to create safe devices. 

[LastRonin]

I have seen the result of a home-built trailer failure. The truck pulling it was heading South at 45mph when the tongue welds gave. The trailer crossed the median into oncoming traffic. Impact with the first vehicle broke the tie-downs holding the box-blade onto the trailer. The box-blade went through the windshield of the SUV in the lane next to the first impacted car. It was very disturbing seeing my wife's coworker, a former nurse, trying to hold the man's skull together enough to keep more grey matter coming out. 

Lend result: five injured, two critical and one dead.

 

Please don't risk anybody's health and safety.

[ThomasPowers]

Artist; This one?  

Mechanics and Applied Heat: A Textbook for Engineers 
S. H. Moorfield

Published by Edward Arnold, 1942

US$5.75 at abebooks.com (including shipping)

Edited June 27, 2015 by ThomasPowers

[arftist]

Artist; This one?  

Mechanics and Applied Heat: A Textbook for Engineers 
S. H. Moorfield

Published by Edward Arnold, 1942

US$5.75 at abebooks.com (including shipping)

Could be Mr. Powers. My memory could have jumbled up those words in the 30 plus years since I lost that book. I would posit that it was printed in the '30s though, but could have had a later printing as well. 

In my life I have never found another text with clearer simpler explanations of real world physics. 

I have to say I would be interested in another copy if only to pass it on to my son. 

[ThomasPowers]

Mechanics and applied heat with electrotechnics: a textbook for engineers Hardcover – 1934by S.H. & WINSTANLEY, H.H. MOORFIELD 

ABE has several copies of the 1930's printings

Edited June 27, 2015 by ThomasPowers

[tonyw]

Thanks for all the replies. This trailer wouldn't be going on public roads, but even though it might hold up, I am probably going to start over on a better design.

[Charles R. Stevens]

The biggist hitch was that you over complicated it, KISS is rule 1, build it 3 times heavier than you think it needs to be, is rule 2, lol. 

[ThomasPowers]

I too had a hitch failure once.  I was driving and felt the trailer come loose and saw it heading toward the other lane so I slammed on the brakes to make sure it hit *my* vehicle.  Had the dent the rest of the time I owned the vehicle. To add insult to injury the tongue was already past the side of my vehicle so when I slammed on the brakes the trainer edge hit and snapped the tongue back towards me and it popped the seal on my rear tire---no damage just a flat.  I added chains and a better hitch after that experience.  I was lucky it was so cheap!

[notownkid]

I've had 2 trailers break on me at welds, both commercially built horse trailers, one brand new about 200 miles from the factory and one a few years old  but not heavily used.   The first one the tongue broke where it was welded to the side frame, I was lucky to notice it when fueling up, caught my eye as something not straight there.  Had to have the factory come out and haul it back to FT Worth and I had to go back to CT without one. 

The other one broke where the bulldog coupler was welded to tongue and the unloaded trailer passed me on the right in the middle of Nowhere at midnight.  Finally hit a culvert at the end of a driveway, went across a guys lawn through his wife's very nice flower garden and the through a large wood pile scattering it all over.  I was met in the yard by a very  upset guy with a huge looking shotgun!!!!  That took a month to straighten everything out.  Didn't help that the cop started laughing when he saw what happened and to whom it happened to as the old guy was always bugging the cops about something.  "He's finally got something to complain about now" was the cops response. 

I check my trailers about every hour when on the road can't be too careful.  If it's going on the highway I will not build it, factory only. on the farm or the woodlot we will except anything loaded heavy esp. log forwarders etc. or tractors.  

[tonyw]

The biggist hitch was that you over complicated it, KISS is rule 1, build it 3 times heavier than you think it needs to be, is rule 2, lol. 

Exactly.

[Charles R. Stevens]

With anything, I am always willing to concede that an "amateur" who cares to acquire the skills and knowledge can exceed the quality and standards of many "professionals". Please, if you are a skilled, contientus professional, you know I'm not talking about you. But we all know the guys I am. The kid that slops together you hamburger "did you drop this on the floor?!" The flat rate mechanic that is trying to beat book, come back rate be xxxxxx " did you see that tire go buy? " carpenters that frame walls and doorways so out of plumb the finished carpenters have to redo the work, and even the electricians and plumbers that slice up so much of the framing with a job saw that the house is only held up by the dry wall (and still the toilet backs up and the roster and the hot water heater pop circuit breakers). This said, their is something to be said for manufactures with good liability insurance! 

[Frosty]

Ditto Charles on hack pros vs. conscientious amatures. Just because doing it for money fills the difinition of professional doesn't make a person a real pro.

I've had two trailers come off my tow vehicle in my life. In both cases I trusted someone else to make sure it was properly hitched. First time it was my FATHER who didn't double check the safety chain! We were moving what we could save after the 1971 Sylmar earthquake and were both stressed. Thank GOD nobody was hurt, just some stuff in the horse trailer, the trailer landing jack and a goodly sized divot in a lawn. NEVER let stress get to you, that's when you MUST follow the check list to the letter! I learned my lesson, you betcha. There's NOTHING like watching your load pass you into oncoming lanes to drive a lesson home! Two lessons learned that day, ALWAYS check your load yourself! AND lose the wheel on the landing jack get rid of it!

The second time was my car hauler. Deb and I were hauling my broken Eagle Talon to the shop and a transient dip in the road made the trailer hitch "top out" on  the ball hard enough to pop the latch and come off. No sweat, that's what safety chains are for right? Well, I HATED that Micky Mouse FACTORY safety chain, it just looped over the ball. I'd checked with, DOT Dept of Motor Vehicles (DMV), Law Enforcement BOTH, Troopers and APD, my INSURANCE and all of them, every darned one, said if I modified it in ANY way all liability became mine.

Well guess how effective THAT "safety" chain was when the trailer went negative tongue weight shock load and the hitch clamp failed? You got it, it did exactly what it was designed to do and slipped off the ball. Another trailer tried passing me into the oncoming lanes but thank god nobody was coming and I could push it off into a deep ditch. Guess what, there were probably 8 State Toopers rendesevousing at the conveinence store when MY trailer WITH MY Eagle Talon came to a screaming top in a spectacualar NOSE stand in the ditch in front of them. With me nearly following them into the ditch as the herd truck.

A few things saved me a HUGE ticket, fine and possible impound, heck maybe jail: The Troopers were using the conveinence store as a rendevous for a funeral procession for a Trooper killed in the line of duty so they weren't about to write tickets if it wasn't necessary. I showed them the FACTORY "safety" chain, he confirmed what I discovered, VIA radio and onboard computer, when I'd called the Troopers and DMV to find out my liability on the thing. And lastly I'd put myself, wife and vehicle in jeapordy doing my level best to mitigate the issue. As more and more officers congregated on the scene I was repeatedly complimented on the fact the CAR stayed chained to the trailer when it went from 55mph to zero in maybe 3' nearly ending up on it's roof. Oh, did I mention I was a professional operator? It was cross chained and reefed down with cross tied with chain binders AND come alongs. You betcha it didn't come off that trailer.

The whole time the Lieutenant! was investigating, more cops were pulling in so we had a real audience. The lieutenant finally directed me after confirming with the Captain who'd arrived to, "Put real safety chains on it." Then he wrote me the coolest citation I've EVER gotten, heck seen. An incident report where he directed me to install proper safety chains and report anyone who gave me CRAP (he used a cruder term on a written report) about it to him for a proper and official butt reaming.

I still have the trailer I put a better, class 2 hitch on it and double safety chains in addition to the factory "safety" chain.

Screw the lawyers, I have to look at myself in the mirror, I want as clean a conscience is possible when I meet Peter.

Now to see if this long reply posts. I'm saving a copy in case it's Forbidden for the post report to Admin.

Frosty The Lucky.

Edited June 29, 2015 by Frosty

[yahoo2]

This is how I learned, model it in copper. Most stuff can be modeled in wire, tube and sheet. It only takes a short time to get a feel for it and a sixth sense kicks in and you can "see" things bend in your mind.

Zero Cost Modelling of Space-Frames

[Frosty]

This is how I learned, model it in copper. Most stuff can be modeled in wire, tube and sheet. It only takes a short time to get a feel for it and a sixth sense kicks in and you can "see" things bend in your mind.

Zero Cost Modelling of Space-Frames

All the link brought up for me were magazine adds.

Frosty The Lucky.

[ianinsa]

Snap!

[Alan Evans]

I pasted "Zero Cost Modelling of Space-Frames" into the auto speed search engine and found issue 650 was all about making copper wire frames to test stresses on structures.

The actual page I found was http://www.autospeed.com/cms/A_112924/article.html

Reminds me of a sculptor friend, Jamie MacCullin who developed a system for designing and testing bridge structures. He made wire frames and then dipped them into washing up liquid (dish soap?. He then digitised the resulting bubbles on the University of Stirling engineering department computers.

I think Jamie may have got the idea from Gaudi who modelled the stresses on his buildings by strings and weights hanging from an inverted plan of the building which he photographed and then turned the photograph the right way up. He was able to use very light pillars at apparently random angles which mirrored the lines of gravitational force…very elegant solution.

I am interested by the discussion re. safety chains. The system over here is to use a light cable which is designed to fail AFTER it has applied the brakes on the trailer. The brakes are on an overrun system when driving, and are manually applied for parking by a lever on an over-cam mechanism. The cable is attached to the bottom of the handbrake lever below its fulcrum. The cable yanks the brakes on as the vehicle and trailer part company then it breaks so the trailer does not cause the tow vehicle to swerve by flailing around on a loose connection.

Alan

Edited July 6, 2015 by Alan Evans

[Charles R. Stevens]

The exepted system here is to have not only a breakaway breaking system as you describe, Allen but a pair of chains, if they are adjusted right (crosed under the hitch and shortend so as to alowe the trailer to swing fully but with a monnimum of slack) with this set up and a competent driver that dosnt panic minimal damage is done to the truck and trilor under most cercumstances and the breaking system alows you to safely stop and remidy the hitch failer. In effect the hitch dropes on to the chains and is prevented from diggin in and fliping, wile the trailer remains atached to the tow vehicle by a soft couple prevented from going back or forward by more than a foot. Once you are strait you can saftly stop, juductius use of the electric brake my be needed to uvercome wag, but as the toung has droped and tranferd more weight to the front it is usualy self corecting. 

As to the Original poster, just saw an advert for an "ATV" goose neck trailer in northern tools. Still looks like a death trap to me but atleast some one else assumes liability

[ianinsa]

So Charles, when the trailer has just killed some dumb kid than didn't quite understand that hitting that bump/ditch with the trailer fully laden isn't the smartest of ideas, you can tell the parents "well at least he gets a nice coffin courtesy of xxxxx trailer co." and after the 10th serious accident they'll possibly have a recall.  I THINK NOT!

[Charles R. Stevens]

Not exacly, Ian but we cant protect everyone from their own stupididty. In the case of the one from northern, i was more woried about some fool mounting it on a ATV with out a roll bare and turning to sharp...

Edited July 6, 2015 by Charles R. Stevens

[ThomasPowers]

Liability is a bit rougher over here with payments in the millions of dollars possible; helps companies put a bit more weight on the safety aspects of their products.

[Charles R. Stevens]

Typicaly 1/2-2/3 of the manufacturing cost is product liability insurance...