Hydraulic Cylinder w/ Brake

[jerry1423]

Is it possible to purchase a hydraulic cylinder with a brake built into it to lock the shaft in place ?
I believe I have seen pneumatic cylinders with them, but not hydraulic cylinders.

Jerry J.
UGV5-NX1899

 

[3DDave]

Hydraulic cylinders don't need them as closing the valves locks the piston in place. A brake would also need to bear against the rod - likely scratching it and causing leaks.

Pneumatic cylinders need them because air is compressible and closing the valves doesn't lock the cylinder in place.

If you need such a thing, use a parallel structure to carry the weight.

 

[jerry1423]

Thank you very much.
You gave me the information I need to speak to the person who asked for the brake.

Jerry J.
UGV5-NX1899

 

[Stick.]

If there will be sustained forces acting on the rod (like a gravity load) and you can't tolerate much or any drift, then you need to be careful about what valve types and/or valve arrangement you select for holding the cylinder. For instance, spool valves have internal leakage, so they'll allow some cylinder drift unless you take other measures to prevent it. I forget all the ins and outs of designing a system for this type of load holding scenario, but the basics are pretty well covered online if you poke around. Similarly, if you're looking to use this brake/load lock as a safety device, then don't rely on the hydraulic fluid to hold the load. Even with a properly designed system, a rod seal blowing, failed hose, etc. will still allow the load to move. Here's a bit of a primer on load holding/locking. It looks like it's basically an ad*, but the first half that I read seemed like it's at least a decent primer to help you search for more info.


*I have no affiliation with the company that wrote the article I linked.

 

[BrianPetersen]

Here's another one that I've seen used.

https://www.sitema.com/en/

 

[DAVIDSTECKER]

Car lifts usually use an external locking pawl tact as a safety mechanism.
Many systems us a Cross Piloted Check valve at the cylinder.

 

[jerry1423]

Excellent Relies. Thank you very much.

Jerry J.
UGV5-NX1899