Top and Tilt on Kubota L39

[smooth_pilot]

Brian,

Don't you get enough vertical float from the TPH itself? It seems that if the tilt cylinder were allowed to float that it would change the relative heights of the scraper blades. E.g. If the top link compressed, the box would tilt forward and the front blade would be able to take a deeper cut, assuming that the weight of the box is being carried on the back blade. Can you explain more?

I can picture that some float in the roll axis might be valuable where two crowned roads intersect but that would need to come from "floating" the side link. I'm pretty sure that you are right about not being able to float a cylinder with DPOCV's. Prince does not offer the option of a float bypass on their DPOCV work sections, either. I guess they figure that if you ever want to lock a cylinder in one position that you always want to lock it.

At this point I'm thinking that I will just go with the non-checked work sections in the valve and put DPOCV's on the cylinders that need them.

 

[HayDR]

Brian,

Don't you get enough vertical float from the TPH itself? It seems that if the tilt cylinder were allowed to float that it would change the relative heights of the scraper blades. E.g. If the top link compressed, the box would tilt forward and the front blade would be able to take a deeper cut, assuming that the weight of the box is being carried on the back blade. Can you explain more?

I can picture that some float in the roll axis might be valuable where two crowned roads intersect but that would need to come from "floating" the side link. I'm pretty sure that you are right about not being able to float a cylinder with DPOCV's. Prince does not offer the option of a float bypass on their DPOCV work sections, either. I guess they figure that if you ever want to lock a cylinder in one position that you always want to lock it.

At this point I'm thinking that I will just go with the non-checked work sections in the valve and put DPOCV's on the cylinders that need them.

A three point hitch is designed to be fixed in all 3 positions. If you use float on one position independently of the other 2 positions, you can expose your implement and tractor to safety issues to which it was not designed. Your three point hitch is designed to float up with the 3 points being fixed. Changing the geometry of your hitch points independently can cause the forces to damage your tractor and/or put the operator in an unsafe situation.

Take a box blade if it contacts a fixed or semi-fixed object with a fixed three point, it will usually floats up and over as a unit. If you have your toplink floating the first thing that will happen is the blade will tilt forward with the front cutting edge going down into the object. This can cause the box blade to be damaged and/or the hitch of your tractor to be damaged. If you are traveling forward at 3 mph and come to a stop instantaneously, your tractor front end can raise off the ground very quickly causing an unsafe situation.

I can think of many situations where independent float is going to make an operation unsafe. If you do not have a DPOCV on your hydraulic toplink, please it is not advisable to use the float position in your hydraulic selection.


Unsafe operations of tractors can kill or severely injure an operator, please think safety first.

 

[smooth_pilot]

Great observation. Corroborates my gut feel.

 

[MtnViewRanch]

I believe that I said that I use float on my tilt cylinder,(side link) not my top link, so the blade riding up forward does not come into effect. And as far as smoothing my roads go, that would be with my rear blade or my roll-over Gannon and with the cutting edge turned around backwards, so that it smooths and does not dig in. It simply rides over any immovable object. It most likely would not be a very good idea to have anything in a float mode while a blade is in a digging mode.

I suppose that I should have made these things clear in my post, but did not, sorry for any confusion.

 

[smooth_pilot]

Thanks for the additional information Brian. Sorry that I didn't pick up on your explanation on the first pass.

I ordered a four-section valve set today. Went with two 4-way, spring-centering valves with a joystick. One 4-way, spring-centering with a single handle. One 4-way motor spool with 3-position detent handle. Fairly basic but it can be easily modified in the future, if needed. I'll post some photos of the mounting mockup once the valve assembly arrives.