Electric brake, E-brake options?

[indiedog]

Couldn't you fix the base of a thread/scissor type wind up jack, or the base of a high-lift jack to the drawbar and then fix the moving section via a pivot to the box? It would need to be fixed both ends to keep the box in position relative to the drawbar.

Do high-lifts resist upwards movement?

The other thing I've seen here is an airbag used as a car jack utilizing the exhaust as the pump. If you could fit an airbag between the box and drawbar this could be a pretty low tech solution. Again you need to stop the box lifting off the bag.

 

[R_Lefebvre]

Second, old#7's illustration above, I think the tongue pivot needs to be closer to the axle. That way it is not so "high" when tipping. I believe this may change the tip rate, but it is still a straight backwards force at 24" (or whatever) above the pivot point (the ground.) Feel free to argue that, it is just my opinion. Maybe Rob or someone can run numbers on that idea.

I disagree. Where the pivot is not, forward of the axle, will actually help as the box goes up. I also don't think it needs a shock absorber. If the brakes are locked, it'll be a case that the more he backs up the truck, the further it will move. It shouldn't ever fall back further than intended unless the tires slip or something. As long as the wheels are locked, and the axle is slightly aft of the box centerline, I think it'll work well.

Now, bolting the tongue box to the pivoting tongue does make sense. That'll make this easier. Just leave whatever gap is required between the main box and the tongue box because there will be some relative movement as the main box swings up.

 

[njtaco]

I disagree. Where the pivot is now, forward of the axle, will actually help as the box goes up.

That's true, but I was figuring that the more she tips, the more load is aft of the contact patch (pivot point) and the less force will be needed to tip further. At some point, the load will start to "pull" the truck and all backwards, won't it? Actually, if it did do that, it might be helpful to have a longer moment arm (terminology?) to control it. That brings me back around to your way of thinking... Huh. (shrugs)

Now, bolting the tongue box to the pivoting tongue does make sense. That'll make this easier. Just leave whatever gap is required between the main box and the tongue box because there will be some relative movement as the main box swings up.

I think the pivot will have to move back some to accommodate this design, based on the illustrations. I think...

 

[njtaco]

Do high-lifts resist upwards movement?

No, they don't. A scissor type screw jack would, though.

 

[indiedog]

My thinking is that if you look at something like the scissor jack method, the necessity for the handbrake is deleted as you aren't relying on locked trailer wheels for the tipping action. I don't know if that would save any cash?

I've seen tipping trucks where the top of the hydraulic ram has a pulley. A cable is fixed at one end to the chassis, runs up over the pulley and down to a fixing point on the tipping tray. This way you get twice the lift out of the jack/ram movement.

 

[Old#7]

Ok now I am wondering if there would be any difference in the forces involved using the indy arms or normal leaf springs. I was thinking, leafs are mounted to the top of the axle, Arms would be connected to the center line of the axle. Leafs would be mounted somewhat in the center of the main box. Arms would extend from the axle to the front of the box, closer to where the tongue pivot is located. I am just brain storming, so someone with a better brain than mine please chime in.

 

[indiedog]

Ok now I am wondering if there would be any difference in the forces involved using the indy arms or normal leaf springs. I was thinking, leafs are mounted to the top of the axle, Arms would be connected to the center line of the axle. Leafs would be mounted somewhat in the center of the main box. Arms would extend from the axle to the front of the box, closer to where the tongue pivot is located. I am just brain storming, so someone with a better brain than mine please chime in.

So my idea that a thread/forum dedicated to suspension types and the different effects on the trailer loads still looks like a good thing!!?? Is this something the administrators could do? I see liability issues for one. But general issues and methods could be outlined...... There's a vacancy here for a "trailer engineer". R_Lefebvre, are you available??

Realisticly, leafs are going to get you 99% of places you wish to go to no problems. Trailing arms, while a better suspension, really are a bit of a luxury and well marketed. The equivalent of trailer BLING Nice bling though.

 

[R_Lefebvre]

Ok now I am wondering if there would be any difference in the forces involved using the indy arms or normal leaf springs. I was thinking, leafs are mounted to the top of the axle, Arms would be connected to the center line of the axle. Leafs would be mounted somewhat in the center of the main box. Arms would extend from the axle to the front of the box, closer to where the tongue pivot is located. I am just brain storming, so someone with a better brain than mine please chime in.

Nope, won't make a big difference. All that matters is where the pivot point is. In this case, the pivot point is the contact patch under the tires. Doesn't matter what you do after that.

Yeah, I dunno if I want to be the official "trailer engineer". I just help where I can.