Hope you are doing good.
Can anyone please explain to me why actuators are mounted in inverted position on some excavators?
Please see the image for better understanding of my question.
Another question is, why on some excavators there is a mix of rigid and flexible piping instead of having completely flexible piping to supply hydraulic power to the actuators?
Thank you in advance for your answers.
Piping: Flexible is used where needed - to accommodate joints and movement.
Fixed pipes are used as they are cheaper and also need to have less fixings per length.
As for “inverted” which of those is inverted obviously excluding the one horizontal… So, given how the actuator works - as it is double acting then it makes no difference apart from the required space around each end. However, it can be seen that the cylinder end is always closest to the supply point in the right hand image, while in the left hand image the cylinder end is likely being kept away from a riskier place of damage.
A single acting actuator is ususally positioned so the hydraulic force opposes gravity or the “normal” closed position or rest position.
Everyone keeps mentioning ease of hydraulic connections, but one could alternatively design the hydraulics to fit the cylinder orientation, yet it is almost never done. This is partially because there is little difference for the cylinders themselves. Consider at least one more step in why the hydraulics might be designed as they are. Here is one possible consideration.
For the Caterpillar pictured, the circled cylinder and associated hoses are easy to service. The adjacent one might be slightly more difficult.
If however you had to replace all sets of hoses, then the Liebherr design might actually come out ahead compared to an equivalent sized machine built in the Cat configuration. This is because a lot more is in a common area to all 3 cylinders on the Liebherr.
Why would someone prefer one over the other?
Mine/quarry bottleneck can be the transportation of material out, meaning missing a single shipment is a considerable cost compared to hoses. Delaying a train by a few hours to make your quota? It could affect the whole line and everyone using those tracks. Delaying a truck? It'll take the same amount of time to make the round trip anyway so it will remain behind forevermore. If you're replacing one, might as well replace even slightly worn ones rather than using the full life of the hose.
Renting out or owning construction equipment? Even if someone has to fix a down machine, work (or rentals) can still go on as long as your plan was flexible enough. Using the full life of equipment just makes sense.
