Pneumatic actuators - locking mechanism?

[Sudorrac]

The problem: I was planning on using pneumatic linear actuators for a deflector - to direct the material from a conveyor, correctly down the chute - and i needed the deflector to be adjustable. The deflector itself is made out of chromium carbide clad plate, it will weigh atleast 100 kilos or more. Can i directly link a pneumatic cylinder to the deflector plate, or would the external downward force create too many problems? Also - is there a self locking cylinder that will allow the cylinder to remain in place once moved to a certain position.

I will also be mounting a second pnuematic cylinder, that will be hinged in order for me to get rotation of the deflector.

Any help in this area would be appreciated, cheers :)

 

[pantaz]

I do not believe you can safely or accurately hold pneumatics at less than full travel (i.e., fully extended or fully retracted). A physical latch/lock would be needed to hold position at partial extension. Another option is air-over-hydraulic. It may not be any less complicated than fitting some kind of mechanical device, but it can offer more operational flexibility.

A very helpful reference I use is the website for Hydraulics & Pneumatics (industry magazine). Here is their overview on combination air/hydraulic devices:
http://www.hydraulicspneumatics.com/200/eBooks/Article/True/67385/

 

[malemdk]

you can use pneumatic cylinder for this application and you can have achieve self locking by using mid position locked direction control valve