Any hydraulic experts out there?

[Matthew Storrs]

I'm setting up a postknocker to run off a digger- but I want to be able to control the hammer from controls on the postknocker rather than the digger.

 

So I have a double/single acting circuit on the digger. But the ram on the postknocker is a single acting ram (same As on a tipper truck) so the weight gravity forces the ram back down.

 

I'm looking at lever control spools but do I go for a single or double acting one?

I don't want the hammer to drop when I let go of the lever- I want to press the lever the other way to make it drop so not sure which one I need.

 

Cheers, Matt

[Goaty]

Will try and have a look on our bryce tomorrow i imagine returning the oil unhindered to resevoir plays a big part through a. Wider bore pipe. I reckon the return port on the valve makes a difference. The return will go straight back to tank out the block whereas. A double will have valves inline. Im sure all our block Is double. Ill email you.

 

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[Joel77]

We've got one that goes in between the post knocker and power pack or digger just a box worth sliding switch on / off

 

Works well looks like it was made up

[farmer rod]

I'm setting up a postknocker to run off a digger- but I want to be able to control the hammer from controls on the postknocker rather than the digger.

 

So I have a double/single acting circuit on the digger. But the ram on the postknocker is a single acting ram (same As on a tipper truck) so the weight gravity forces the ram back down.

 

I'm looking at lever control spools but do I go for a single or double acting one?

I don't want the hammer to drop when I let go of the lever- I want to press the lever the other way to make it drop so not sure which one I need.

 

Cheers, Matt

 

Not much of an expert, but go for a single acting, the connections on the digger become flow and return, and the one pipe to the knocker ram is all you need. Just be aware that the digger will be pumping oil round all the time and the returning oil from the knocker will be competing for a route back to the tank, depending on pipe sizes /plumbing this may slow down the descent of the weight. If it does, then fitting a free flow return straight to the tank will sort it.

[Breezeblock]

I'm setting up a postknocker to run off a digger- but I want to be able to control the hammer from controls on the postknocker rather than the digger.

 

So I have a double/single acting circuit on the digger. But the ram on the postknocker is a single acting ram (same As on a tipper truck) so the weight gravity forces the ram back down.

 

I'm looking at lever control spools but do I go for a single or double acting one?

I don't want the hammer to drop when I let go of the lever- I want to press the lever the other way to make it drop so not sure which one I need.

 

Cheers, Matt

 

you need a valve which is open centre the aux hydraulics will be under load all the time if you don't go for a single acting valve if you don't when you push the opposite way to drop the weight you will be putting power to a dead end and opening up the valve to drop the weight

[Breezeblock]

send me a link to the valve that your thinking off

[Matthew Storrs]

send me a link to the valve that your thinking off

 

Thanks for all your help everyone. Breezeblock- this is the valve I had in mind https://www.flowfitonline.com/hydraulic-valves/monoblock-valves/bucher-hydraulic-38-40-lmin-one-bank-single-acting-spool

 

I'd have a thick hose as the return hose- not sure what size but I guess it's also limited by the 3/8 adapter connection too to get the oil to get back to the tank quick enough so the weight has maximum drop velocity?

[Breezeblock]

yep that should do the trick I would be tempted to try and get a 3/4 valve of the same style as the least restriction the better when it comes to post knockers even though its reduced to 3/8 you will need to find a way to hold the aux hydraulics on for it to work whether its jam a brush under the pedal or rig a switch.For this to work at its best you would benefit from fitting a 2 way valve on the return so the oil goes straight to the tank return filter missing out the valve block