Question on Half Torsion Axles

[Geron]

Looks fine to me. A couple of comments:

- The 2.5" square tube will be more than 7 times as strong as each 2" angle, so the angle won't add much vertical strength. The angle seems to stop only a very short distance in front of the trailer floor, so it also won't add much horizontal strength.

- I'm not a big fan of these composite tongues (ie, central tube and angled braces) as one or other of the parts isn't doing much good. You could throw away the centre tube and just use stronger tubes for the angled braces.

Andrew

Gee, Andrew, Just got back with the metal. Could have done as you suggested and used a triangular coupler as well. Oh well, NEXT???? Build.
But, Just as long as this will work, I'll just have to proceed as planned.

Geron

[angib]

Heck, you shoulda said you were off to buy metal and I woulda kept my mouth shut......

Andrew

[Geron]

Heck, you shoulda said you were off to buy metal and I woulda kept my mouth shut......

Andrew

Thanks anyway, Andrew, Maybe good for someone else.

Yeah, got impatient waiting for an answer. Not a good character trait.

Thanks anyhow,

You shoulda been a little more severe with me. I need a good dressing down on occasion

Geron

[Gaston]

Hi Geron
you might want one of the "engineers" here look over the attachment of the axles to the floor of your trailer. With torsion axles the "twist from wheel movement is transmitted to the attach point of the axle housing and is increased by the arm length between the stub axle and the torsion box mount.
so if your trailer is around 1000lbs and you hit a big chuck hole, and your axle has little or nothing to keep the torsion box from rotating, then I reckon you would be "fixen" to be "pickin" up the pieces.
when it comes to suspension its always good to plan on "savin" a little weight some where else so's you can use it where it counts as in keepin the wheels under it
course as I said I ain't no engineer but ....

[Geron]

Hi Geron
you might want one of the "engineers" here look over the attachment of the axles to the floor of your trailer. With torsion axles the "twist from wheel movement is transmitted to the attach point of the axle housing and is increased by the arm length between the stub axle and the torsion box mount.
so if your trailer is around 1000lbs and you hit a big chuck hole, and your axle has little or nothing to keep the torsion box from rotating, then I reckon you would be "fixen" to be "pickin" up the pieces.
when it comes to suspension its always good to plan on "savin" a little weight some where else so's you can use it where it counts as in keepin the wheels under it
course as I said I ain't no engineer but ....

Thanks Gaston,

Just a review:

Currently I have a 2x12 yellow pine (wish I coulda found some Oak) underneath the floor all the way across -- I think you can see it in one of the pics. The torsion axles attach to this 2x12 with 12 - 3/8" grade 8 bolts (Six on each axle). These bolts go completely through the floor with big washers underneath the heads of the bolts. The bolts closest the the side of the floor are so close to the edge of the floor that I decided to "edge" the side of the floor in proximity to the axles with 1 1/2 x 1 1/2 x 1/8" angle iron through which these two bolts (two on each side) will be run. The "tongue" will be attached through the 2x12 with 2 grade 8 bolts securing the 2x12 in the middle of the trailer.

I had planned to glue the 2x12 to the floor with polyurethane but considered it redundant with 14 bolts holding the 2x12 to the floor of the trailer.

That's where I am at present. I appreciate all suggestions.
As Ben Franklin said:

“Experience is a dear teacher, but fools will learn at no other.”
Geron

[Podunkfla]

Currently I have a 2x12 yellow pine (wish I coulda found some Oak) underneath the floor all the way across -- I think you can see it in one of the pics. The torsion axles attach to this 2x12 with 12 - 3/8" grade 8 bolts (Six on each axle). These bolts go completely through the floor with big washers underneath the heads of the bolts. The bolts closest the the side of the floor are so close to the edge of the floor that I decided to "edge" the side of the floor in proximity to the axles with 1 1/2 x 1 1/2 x 1/8" angle iron through which these two bolts (two on each side) will be run. The "tongue" will be attached through the 2x12 with 2 grade 8 bolts securing the 2x12 in the middle of the trailer.

Gaston sure has a good point. The 2 x 12" is plenty strong... but it may be much better to run it front to back to transmit the torque of the axle over a longer area. I think the way you have it pictured it is going to cause a lot of flexing in the floor when you go over bumps. It may not fail, but it sure could loosten up the floors attachment to the sidewalls. You could also use a length of angle iron along the edge of the floor front to back to spread the load too... Then you wouldn't need a big heavy 2 x 12" across.

Personally, I'm not a big fan of frameless design because a simple steel frame prolly doesn't weigh significantly more, if any. Good 'ol Andrew could prolly splane this a lot better than me...

[Geron]

Guys,

I gotta be the world's worst when it comes to 'rightin' ideas down on paper. I get way ahead of myself. This is not really frameless. Check this out 'cause I think it address some of your concern for my enginerin' and torque problems.

This is "framing" approaching "minimal"



The torque will be transferred to the sides with the Angle Iron on each side with the axle bolted through the angle iron and side. Residual torque will be picked up by the angle brace bolted to the axle and the extended forward and bolted to the floor of the TD.

Anything left over will be picked up by the square tubing which extends forward for the tongue and is bolted to the Floor.


Is that better??? NOT perfect -- just better?:crazy:

Geron

[angib]

Two things (now that I've seen what it is you want to do):

- I would like to see the angle iron extended as far behind the wheel as you've gone in front. Remember the wheel load comes at the spindle, not at the torsion axle, so at the moment it looks like you've got most/all the angle in front of the wheel. (Far side of photo looks better, though.)

- The joint between the 2x12 and the side framing is very important, with or without the angle iron. I'd like to see epoxy in that joint - I'm not convinced that poly-whatsit glues have got enough ductility for this application. The joint between the side wall and that side framing is also vital, but there's so much glue area that any decent glue will do there.

Andrew

[Geron]

Two things (now that I've seen what it is you want to do):

- I would like to see the angle iron extended as far behind the wheel as you've gone in front. Remember the wheel load comes at the spindle, not at the torsion axle, so at the moment it looks like you've got most/all the angle in front of the wheel. (Far side of photo looks better, though.)

- The joint between the 2x12 and the side framing is very important, with or without the angle iron. I'd like to see epoxy in that joint - I'm not convinced that poly-whatsit glues have got enough ductility for this application. The joint between the side wall and that side framing is also vital, but there's so much glue area that any decent glue will do there.

Andrew

Excellent,

All this I can do.

I had considered large screws (along with the epoxy now) through the side framing into the 2x12 but wondered if the weakening of the side framing (bydrilling holes and inserting screws) would offset the strength gained by the screws.

Geron