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  #1   IP: 31.185.213.49
Old 15-12-2017, 10:33 PM
grahams grahams is offline
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Default Converting breaker circuit to double acting

A guy who works for me is looking to buy a small excavator second hand for use on his land and we were talking about running stuff off the auxiliary circuit. Most of the older machines he is looking at only have one way circuits, but ideally he would like to be able to run a timber grab. Is it difficult/expensive to convert a mini digger of around 3t size from a one way to a two way auxiliary circuit?
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Graham
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Old 15-12-2017, 11:28 PM
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V8Druid V8Druid is offline
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Default Re: Converting breaker circuit to double acting

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Originally Posted by grahams View Post
A guy who works for me is looking to buy a small excavator second hand for use on his land and we were talking about running stuff off the auxiliary circuit. Most of the older machines he is looking at only have one way circuits, but ideally he would like to be able to run a timber grab. Is it difficult/expensive to convert a mini digger of around 3t size from a one way to a two way auxiliary circuit?
Thanks
Graham
cheapest way IMHDO would be a one way cetop3 ..... P in, T out of base manifold.
energised the flows are reversed ....

so.... de-energised = P to A & B to T

energised = P to B & A to T

one single button to change from default to reversed flow

https://www.flowfitonline.com/hydrau...open-to-t-port

https://www.flowfitonline.com/manifo...-side-entry-38

if you wanted more than one service from that single source that's possible too, with double acting cetops and a manifold.
same as I have my VA-r set up Gra

one single acting feed split 1, 2, or 3 ways .... or more if you're greedy

could have rotate and grab simultaneously doing it that way, but need a button for each action ... i.e. 4 actions = 4 buttons. 2 buttons per stick

open / close, rotate left / right

pretty straight forward and probably the cheapest options
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Old 15-12-2017, 11:42 PM
grahams grahams is offline
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Default Re: Converting breaker circuit to double acting

Relatively straight forward and not huge money then.
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Graham
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Old 16-12-2017, 12:35 AM
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Default Re: Converting breaker circuit to double acting

A lot of machines come from the factory with a single acting auxiliary circuit consisting of a one way pilot operated foot pedal operating the output on the auxiliary valve section of the main valve block. In a lot of cases, the aux valve section is actually a four way valve already, they just use the A output port to feed the aux circuit then send the other aux pipe back to tank, and they simply put a plug in the B output port on the control valve. You simply remove the plug, connect the hose on the return pipe to the B port of the control valve, install the required port relief for the B port (not installed from factory because port was plugged). Then you just replace the foot pedal with a double acting pedal and run another pilot hose from the pedal to the B side of the control valve. You could find another pedal easy enough. There are a few options available.
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Old 16-12-2017, 12:54 AM
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Default Re: Converting breaker circuit to double acting

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Originally Posted by grahams View Post
Relatively straight forward and not huge money then.
Thanks
Graham
I'd reckon the dearest single items'd be new stick tops with buttons TBH Gra ...
doing it that way, at least, if you wanted to do more than just make the single service reversible.

If you simply wanted to mount a grapple (or a hydraulic thumb) a single button could even be foot op.

I'd make the default action to grip/close, so that it would need a deliberate operation of the button to release grip.

I'd also recommend plumbing the grip action through a pilot operated check valve, mounted at the extend port on the ram, as the hoses allow the grip to release ever so slightly and you lose that nice tight 'bite'.
Made a world of difference to my Cranab hanging onto a couple of tons of rock ... it didn't let go at all.

https://www.flowfitonline.com/hydrau...lves-type-a-38

if you wanted to dangle a grab on a rotater, could still be done using that method, for rotate and put a 6 x 2 diverter valve in the crowd circuit to change over from crowd to grip (I'd have the solenoid switched with a non-momentary / on-off switch .. set the crowd, then switch it over to grip and leave it set) grip/release would then be on the stick instead of crowd

https://www.flowfitonline.com/hydrau...-80-lmin-flows

you do need an open to tank 1/4" drain line on those 6 x 2s though to drain any leakage in the valve body
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Last edited by V8Druid; 16-12-2017 at 12:58 AM.
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Old 16-12-2017, 09:51 AM
grahams grahams is offline
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Default Re: Converting breaker circuit to double acting

Thanks for the replies. If and when he gets a machine it doesn’t look to be a huge drama. Although we may be back for more advice at the time.
Graham
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