Lowering rate restrictor for a FEL

   / Lowering rate restrictor for a FEL #1  

jigs_n_fixtures

Platinum Member
Joined
Jul 31, 2021
Messages
844
Location
Salmon, Idaho
Tractor
TYM T233
So I ordered wheel weights for the tiny tractor, and today when they showed up, I lifted them off of the truck, with my pallet forks.

They were fairly heavy, so I ran the engine speed up to have enough hydraulics to lift them. And, of course it was really happy to go down fast.

so, I got to thinking about it, and have decided that I want to put a restrictor in the line from the cylinder to control the fluid flow, and thus the drop rate. Thinking further, I came up with an idea for an electric splitter valve for the lift/lower circuit, which would let you switch between a normal circuit, and one with an adjustable needle valve. Similar to what the three point has.

So, am I reinventing the wheel? Is there someone out there with a kit?
 
   / Lowering rate restrictor for a FEL #3  
They do make adjustable flow control valves that control flow in one direction and open the other. Don’t think you would want to restrict flow in the lift circuit with a typical needle valve. Some tractors have regenerative valving to improve loader performance and adding restrictions might not be a good idea.

On the M59 I have a pressure gauge plumbed in on the loader lift circuit. Much bigger tractor. When lowering a load the pressure goes up and can tell a slight engine load. It’s like the valving is trying to cushion lowering the load when moving slow. Don’t know enough to know if this is an added feature or not. Do know the controls are smoother than similar size tractors I’ve used.
 
   / Lowering rate restrictor for a FEL #4  
I call it my arm.

It determines the amount of feathering of the joystick. It allowed me to safely lower a 400 pound $4,000 generator.

As Diggin It mentions, why can't you control the rate at which your FEL lowers? Unless you shove it up into FLOAT and let gravity take over, you should be able to lower any load very slowly by feathering the valve.
 
   / Lowering rate restrictor for a FEL #5  
Some valves just do not have good feathering at all. Using a flow reduction valve helps with those valves.
 
   / Lowering rate restrictor for a FEL #6  
K5 is correct in that some valves have little to no metering built into them.

two speed circuits are not uncommon in the industrial world but seem a little less common in the mobile world
 
   / Lowering rate restrictor for a FEL #7  
Lack of feathering capability can sometimes be traced to valve selection. A valve rated for 2x-3x the gpm of the pump's rating will not feather as well as a valve more closely matched to pump capacity. Operator skill is certainly a factor as well. It's easy to blame a valve, but a valve with poorly constructed spools is not terribly common. Control valves are a mature technology.
 
   / Lowering rate restrictor for a FEL #8  
Rick
You are correct in valves being a mature technology but I have tried four different valves on my Branson and non of them feathered very well. Original valve was zero feathering when lowering other three have a little bit. One of them load checks kept leaking and another float did not work. Manufacturer even admitted was design flaw in that valve series and discontinued that feature My tractor only produces around 4 GPM at full throttle and vast majority of FEL valves are rated for 10 - 12 GPM

looking in work ports at the spools I only saw metering grooves on the one valve so unfortunately I think on these low cost CUT valves the metering is poor compared to valves on larger tractors
 
   / Lowering rate restrictor for a FEL #9  
Interesting! I didn't realize that it was common to find loaders where you couldn't easily control the rate of descent of a loaded bucket or forks. Seems both dangerous and damaging. I'm often trying to lower an object or a pallet gently without damaging it or the surface (truck bed, trailer, etc.) that it's going down on. I simply couldn't operate with a loader that I couldn't control so I understand the desire to throttle it back somehow. But won't this limit flow in both directions?
 
   / Lowering rate restrictor for a FEL #10  
CH4, The adjustable type tend to control flow in one direction and allow full flow in the other.
 
 
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