Please explain 1/4 inch valve...?

[Coyote]

I have read about this but cannot visualize how it works. My old tractor just goes up and down smoothly. Does it mean that there are "stops" every 1/4 inch? Does that make it hard to hook up implements? Help me understand what it means real world. Thanks!

 

[George2615]

I don't really understand the question but a 1/4" valve usually means the inlet / outlet of the valve are 1/4" whether its for 1/4" pipe or for 1/4" copper whether threaded or soldered on and the orifice through the valve is 1/4".

 

[MDM]

Hitch arms raise in 1/4 inch increments.

 

[ChuckinNH]

I'll give this a try. When pushed all the way to the down stop, the TPH arms drop all the way just like the tractor you are used to. When the control lever is raised all the way to the up stop, the TPH arms raise smoothly all the way to their top limit. If the linkage is adjusted properly ( it's fussy) when the control lever is pushed to either stop, and released it returns to the center position by itself, and the arms have moved 1/4" up, or down as the case may be. I'm sure that is not an exact amount, but it does allow one to make minor adjustments with some degree of repeatability. Most of the "B" series that have that feature that I have looked at have been improperly adjusted, but the new BX series that I've seen have been properly adjusted, and make it easier to understand how it is supposed to work. If you were to "bump" it the same number of times from the full down position, for example, it would raise the same amount each time, or at the beginning of each pass. Not quite position control for sure, but better than just full up, or full down....
Hope this made some sense,
Chuck

 

[Fjord]

I've played with the quarter inching valve on my B7800 quite a bit and got the stop positions adjusted to something that works for me, but its really just a plain old valve with a couple of mechanical stops on the side of the lever slot so that if you pull it to the side and it hits the stop then it just raises or lowers really slow because you havn't pulled it all the way back.If you hold it at the stop postion long enough it will eventually go all the up or all the way down. The lowering rate is also a function of where you adjusted the lowering rate valve and the weight of the implement.On mine I just adjusted them both so that they're really slow, then I put a piece of rubber in the lever slot on the raising side so that even after I've left the stop position I still have to actually pull on the lever to get it to go up. For me this gives better control. I've also made a device that will tell me how much I've raised or lowered it. You have to actually play with it for a while and get used to how it works with each of your implements.You get used to it after a while, but for the amount of negative things that people say about it I don't know why they don't just put on position control or make it an option. I consider it a bit of an inconvenience but not so bad that it justifies buying a premiun tractor. Maybe someday they'll come out with a position control retrofit but by that time I might be so used to the QIV that I'll still say it's not worth it.

 

[DVR]

the bigger issue for me was the fact the hitch arms would not stay put.
it required constant adjustment unless you shut the valve that locks the hitch in position. then you had to open the valve before lifting or lowering again.

i agree- it is surprising they have not changed it.

 

[crbr]

Hitch arms raise in 1/4 inch increments.

The one and only flaw in this is that is doesn't work. If it does I commend anyone who proclaims to achieve the precise 1/4" movement setting... In my opinion, it's one of Kubotas continued failures. Other than that and the HSD safety switch, I like the Kubota machine.

 

[Fjord]

the bigger issue for me was the fact the hitch arms would not stay put.
it required constant adjustment unless you shut the valve that locks the hitch in position. then you had to open the valve before lifting or lowering again.

i agree- it is surprising they have not changed it.

Maybe a minor point, but that locking valve only stops the arms from going down. You can still raise when it's closed but have to open it again to lower. I guess the end result is the same -a bit more adjusting of things. I got to give the position indicator that I made back in the winter its first practical test this past weekend while using the bush hog. Since my bush hog is an old one that's missing the wheel, I just hang it off the 3pt and cut grass and weeds with it using it more like a RFM. The position indicator actually worked quite well as it allowed me to see how much I was raising or lowering it and if the 3pt was dropping it would also indicate how much the 3pt had sagged so I would know when to lift it again. I was using it without the lock valve closed and the sagging didn't turn out to be much of an issue as I was re-positioning every few minutes anyway due to terrain conditions. I guess you don't have to deal with any of this anymore now that you've got the L3400.

 

[bialecki]

I have found with my B7800 that the 1/4 inching valve is just that, the resolution of the increments up or down can be made in 1/4" increments. This way one can approximate a certain setting and possibly go back to that same position through trial and error of raising or lowering the 3pt hitch arms. I found for repeatability I must use gage wheels on my implements such as a rake. Same with the MMM, the gage wheels are what establishes the cutting height not the 3 pt hitch position.

I understand that position control one can get a more accurate repeatable position. This system may have a feedback circuit (most likely mechanical such as a spring internal to the unit) to assure proper positioning if an implement starts to digs into the ground as with a rake when the tines bite into the soil.

 

[art]

I'm not going to break up for all that I saw wrong here but it should not drop any more then any other hydraulic cylinder should.
You can fine tune your desired height with consistency unlike a position control which varies with raising or lowering. I normally like with a box scraper will lower it to the ground, then raise it a click or two depending on the implement. I've never measured it but it is close to 1/4"!