Upgrading hitch....

[chief916]

On 6/29/2021 at 9:30 AM, trimster said:

Anyone mounted a Trailer Saver TS3 to an HDT? Use standard mounting rails? Or something beefier?

I'm now researching a shop to install it in Albany,  Or.

 

I used standard mounting rails on mine, I pull about 20/21 k. Several years now. No problems. But I am going to put a plate under it, just have not had the time.

[trimster]

Another rock-your-world run yesterday. Hitch performed well.

I have it aired about 1" above the suggested fill mark (mark is 1" higher). I think it's dialed in for this trailer. Watching the hitch-cam, it's busy doing its thing, taking the abuse.

I am going to pull the shocks on the hitch when I hit home base and see if they are still working after all these years (2008 build date).

 

[phoenix2013]

As part of the project I am doing I had a chance to "forensically" examine a Trailer Saver I had, hence the detailed reverse engineered drawings.

The most interesting thing I discovered that the hitch when inflated "to the mark" has only 1.04 inches of travel before it it hits hard bottom. It was quite evident on the unit I have been examining that it was bottoming extensively. It was a three bagger but that was not sufficient on a well over 30K GVW rig. 1 inch is a decent amount of travel for a great percentage of motion experienced while pulling  particularly with a lighter pin weight that you have. Raising the platform another inch will further reduce the possibility of bottoming.

Keep in mind though that the position of the head vs. the the main forward swivel pin has to do with the chucking reduction. The forward chucking forces are significantly higher than the pin weight and can reach upward of half the GVW weight of the trailer, that was what primarily wore out the unit I examined.

Note that if you raise the head 1 inch the head swivel pins, which are the first things that experience the forward chuck force vector, will be almost in line with the forward swivel pin.

Having the head as low as possible in relation to forward hinge is a fundamental facet of air suspended hitch designs, Trailer Saver paid attention to that in their original engineering. There were negative examples recently of what happens when the head is above the forward hinge.

 

Edited July 17, 2021 by phoenix2013

[rickeieio]

 

4 hours ago, phoenix2013 said:

There were negative examples recently of what happens when the head is above the forward hinge.

Down on the farm, we'd call that "going over center."  Never a good thing.

I had my leveling valve set to have the Trailersaver ride at the line on the side of the hitch.  I never had any issues with it, and it weld up well with our 21k lb. trailer.

That said, there's an ET on the KW.  

[trimster]

5 minutes ago, rickeieio said:

 

Down on the farm, we'd call that "going over center."  Never a good thing.

Understand. But I'm playing with some close clearance on the pinbox and the bed. Still playing with this. I need to jack knife the rig and look closely at what's going on back there. My hunch is that I can let the hitch down a bit.  Just being cautious. 

[phoenix2013]

4 hours ago, rickeieio said:

 

Down on the farm, we'd call that "going over center."  Never a good thing.

 

Interesting phrase, but aptly describes the problem. In hitch design it is also critical to consider what happens when things "go over the center" and how to control things when it happens. In an ET it's the two horizontal stop plates projecting over the platform in the rear. In 2011 it was a Greyhound bus hitting a trailer and an ET.

The plates were 1/4 inch thick and did most of the job but not all of it. They were reengineered to 3/8 thick. Forward a decade later.

The 3/8 thick plates held everything together, zero damage to the ET other than an overstretched head spring.

Similar situation here, trailer wants to lay down on its side.

The stop mechanism is a stud with a washer and a nut on top of it.

[GlennWest]

The 2011 greyhound incident convinced me the ET hitch can save a life. If that had been any other hitch the 5ther would have kept coming into back of truck. They were driving an HDT so that was a plus also. A dually would have been possible deaths.

[phoenix2013]

There is a bit of interesting history behind that hitch, it was # 2 ever built after my prototype. After spending over $6K and six months building the original ET I vowed never to build another and kept that "commitment" for almost two years. Marvin Marcy saw the hitch and being an engineer was intrigued by it's design. He called me out of the blue and proposed, "Henry, I don't care what you charge me and how long it takes, I want one". Number 2 took two months to build and I did not charge him six grands. I went to North Carolina to install it in his truck and exacted a promise to tell nobody where he got it. That lasted until he went to his next Rally and spilled the beans.

Marvin was also of the opinion that if this wasn't an ET he might not be around, his semi was a day cab with nothing behind the seats but a sheet metal. The accident was a result of a big slow down on the highway, Marvin was able to get around the vehicle in front of him and get into a breakdown lane, the Greyhound bus behind him didn't. Marvin's fifth was a 40 foot Newmar which had a massive double stack main frame, the bus hit it at an angle and pushed the frame on the side it hit 3 inches forward and totaled the Newmar. Marvin's truck was totally unaffected. Rather than hire tow truck for the Newmar, they hitched it up to the ET as it was and towed it 5 miles to the nearest place where they could store it.

Marvin would not have anything but an ET for a replacement hitch, which I promptly got goin on. But note the "teachable" engineering concept incorporated into that next hitch.

 

The next ET (his) had the 3/8 thick stop plates and note the massively increased front shafts saddles to prevent the shaft shearing I've seen in the pictures. The improvements were designed in such a way so they could be easily incorporated into the early models. Most have been upgraded. Marvin and I have been good friends, I considered him my "co-pioneer" in making an ET a reality, unfortunately he passed away few years back.

 

Edited July 18, 2021 by phoenix2013

[trimster]

Thanks for sharing this. These hitch 'systems ' are complex and interesting to say the least.

[aknavy]

On 7/7/2021 at 4:33 PM, trimster said:

Hitch installed. Whooohooo!

The shop did a great job and did it in essentially one day (picked up the truck 10am the next day). Went above and beyond. If you need work done in the Albany, Oregon area.... Sheet Metal Solutions. Big operation that knows what they are doing.

I was a rush job, they squeezed in. Only $920 out the door. I was expecting way more. Like most places out here, cash saves you 3%+ credit card fee.

 

 

I replaced my TSLB with the new version this weekend.  The flange/base is a different size, and they moved the bolts from fore/aft to port/starboard.  I had to add more 2"square tube to get the height I need.  Had to drill 10 holes thru 2" quarter wall square tube and 1/2 inch plate to mount it.  In a campground.  The shop I was gonna use was closed on the weekend.  What a pain in the butt.  I think I would have paid the $920 to have it be someone else's pain in the butt.  As it was, I broke 3 drill bits, nearly broke my wrist, and crushed a fingertip pretty badly.   Drilling thru that much steel free hand is a disaster waiting to happen.  Not to mention moving that beast in and out of the hole it sits in several times with no crane/hoist.  I think you got a good deal!

[trimster]

13 hours ago, aknavy said:

I think you got a good deal!

My thoughts exactly. I love to build this stuff, but you need to know when to fold'em.

[aknavy]

10 minutes ago, trimster said:

My thoughts exactly. I love to build this stuff, but you need to know when to fold'em.

I thought I was all setup with an Auto Hobby shop to work in with lifts, hoists, full set of tools, etc, only to find out their hours had changed and they were closed on the weekend.  So back to the campground I went.

[trimster]

Shot some video of the hitch as I am navigating in a campground. I was looking to see if the pinbox would clear in tight turns with the air pressure set to the line on the hitch. Seems it will. HERE's the video.