Backhoe Pressure Relief

[tshep]

Hi all - I see my BX23/BT600 has pressure relief(s) on both swings and dipper cylinder extend that are rated higher than tractor working pressure.
Is there some standard logic? (I'm guessing where tractor 'falls' into hole with parts extended and gravity pushes relief into operating.)
I would like to understand...

THX
THS

 

[dfkrug]

These are anti-shock RVs. Think of the momentum you generate when you
swing from side to side, then release the joystick. Not only can they protect
your system from over-pressure, they cushion the movements. They are
aka "cushion RVs".

 

[tshep]

Makes sense! Especially for side to side.
Would dipper extend then be to protect from driving off (forward, 'trenching') with the dipper extended?

THX
THS

 

[dfkrug]

Yeah, these are work port RVs, so they protect the hoe whenever the valves are
closed. Driving forward with the dipper in a hole is probably not what the
designer is thinking about, but the shock RV might help there.

One of the toughest things to do with a hoe is to pull on roots while removing
a stump. You apply max force, which then releases suddenly. Also, think
about a full bkt of dirt at full boom/dipper extension.....moving up/down quickly, then
suddenly stopping. Enormous momentum, leverage, and forces there.