Rollback Truck

[DRussell]

On a rollback truck there is five feet of subframe assembly behind the hinge point and 13 feet in front of the hinge point. Would you expect there to be a problem getting the bed down with a single acting telescopic hoist vs two double acting cylinders?

With a single acting cylinder, gravity would have to bring the front of the bed down. With more than double the length of the bed in front of the hinge I'm thinking it would come back down as long as the load is pulled to the front of the bed and the bed brought to the front of the subframe before trying to bring it down.

What are your thoughts?

 

[Mule Meat]

I would not want a single acting cylinder on one.
Having gravity and back pressure control the lowering of the bed is not my idea of safe way of doing things.

 

[Jim.ME]

On a rollback truck there is five feet of subframe assembly behind the hinge point and 13 feet in front of the hinge point. Would you expect there to be a problem getting the bed down with a single acting telescopic hoist vs two double acting cylinders?

With a single acting cylinder, gravity would have to bring the front of the bed down. With more than double the length of the bed in front of the hinge I'm thinking it would come back down as long as the load is pulled to the front of the bed and the bed brought to the front of the subframe before trying to bring it down.

What are your thoughts?

Depends on the length and CG location of the load along the load's length. Likely would be ok most of the time, but not always.

Are you looking at a ramp truck with bad double acting cylinders and want to use one single acting in place of them?

 

[DRussell]

Are you looking at a ramp truck with bad double acting cylinders and want to use one single acting in place of them?

Moving a rollback bed to a different truck and the hoist cylinder lower mounts will have to be redone. There currently is interference with a carrier bearing on the driveshaft.

Bailey Hydraulics has a couple single acting telescopic trunnion mount hoist cylinders on sale right now. They have a 7 ton capacity model for 278 and a 12 ton model for 400. It would be as easy, possibly easier, to mount one of those into it as it would be to redo the double acting cylinder mounts.

 

[Keith True]

I would have zero use for a rollback with one way pistons.I bet 90% of the time I am wiggling the tail up and down to get under something.I've delivered hundreds of small dumpsters,they all ride on the tail,not up front.Relatively light things like rakes,mowing machines,plows,harrows,balers,were all kept to the rear and could be easily unloaded by sliding the body back and forth and up and down.For machinery hauling I spent most of my time in a Mack,with some in a 9500 GMC.I can't count how many loader buckets I've picked up out of the ground with the tail of the body,block up the loader arms,then run the body down and back to drag on the dead tractor.I have a tilt trailer with 33 feet of deck,with a hydraulic winch.I have hauled dozens of machines with that trailer where I had to use the tail to pick up and block blades,buckets,forks,tree shear heads,snowblowers,etc on non running machines.I always used single axle tractors under that,but they had to have a wet system for the pistons and winch.

 

[Tx Jim]

Both roll back trucks I used to pickup tractor/equipment back in '65-'87 while employed at JD dealership had double acting bed tilting cylinders. I think single acting cylinders to control tilt bed wouldn't be a good method.

 

[jon f mn]

If you do t roll the bed back they would work, but once the bed is back the load is behind the pivot and you need the double acting cylinders to hold it or bring it down. With a load on the bed when you roll it back there would be nothing to stop it from tipping uncontrollably with single acting cylinders. And for loading when you pull the bed forward there will be nothing to keep the bed from tilting further and further til the end of the cylinders.