dead dropping a dozer blade

[Plant Fitter]

It's all down to flow rates. When the blade cylinders move downwards if they move too fast they can actually demand more oil than the pump can supply. The purpose of the quick drop valve is to send the return oil coming back to tank from the rod (bottom) side of the cylinder direct to the piston side of the cylinder so that the pump does not cavitate. It's there to protect the system, not to let the operator drop the blade faster .........

Thanks for explaining.

 

[rk668ak]

I work at a coal power plant and we have 2 992 dozers they have been equiped with a dozer blade instead of a loader bucket. WE have a concrete pad outside our shop and 1 operator drops the blade ever time he sets it down. These blades are 25 feet long and 9 feet tall so when it hits the ground we no who is running this machine. It shakes the whole building.

 

[d9gdon]

I have noticed on some Cats, like a D7E 48A or D6C 10K that some don't have the quick drop valves on the lift cylinders. The Army version of the D7E didn't have them.

My question is if it's for system protection, why would it be an option? Or, are the valves relocated from the cylinders for some reason?

Here's a military D7 without the quick drop valves on the cylinders:

http://www.machinerytrader.com/listingsdetail/detail.aspx?OHID=8432601&

Here's a 48A with them:

http://www.machinerytrader.com/listingsdetail/detail.aspx?OHID=6173166&

 

[Old Magnet]

Yes, I'd like to see more info also as at least at one time on the older stuff the blade quick drop valving was an operation option. Had nothing to do with pump cavitation protection which was handled by seperate "make up" valving. Blade drop was also a controlled event with quick or slow drop depending on amount of lever movement to the control valve.

I'd post the Cat quick drop info but it is two solid pages of reading.

Can't say what the systems may have evolved to........

 

[Garrie Denny]

And costly fixes. Carbs only had 3 parts that could stop vit working properly and any monkey could fix them.