cnc model 7050 actuator Powerlift

[filltbo]

I have half repaired a 7050 actuator (power lift).... it pushes the rod out, but does not pull it back in.

I had to dismantel the whole thing because it had sat in the weather for over 5 years. I got the motor working, and then noticed the the push rod was stuck. When I drained the oil and took the top off... two ball bearing fell out. And you guessed it... i did not see which holes they came from. It seems that they can only go into two holes because the little valves go into the other free holes.

Does anyone know where the bearing should go?.... or have any other idea why it only pushes out? Is there a hidden check valve I do not see that needs to be freed up?

 

[Don S]

Re: cnc model 7050 actuator Powerlift

Sounds more like a hydraulic problem than an electrical, so will move this over to Boat topics.
Assuming THIS is your unit, might look under the resources for info, or even give them a call and ask.

 

[filltbo]

Re: cnc model 7050 actuator Powerlift

I got it figured out! When the end cap comes off picture swiss cheese. There are over a dozen holes that you can see through... those are for bolts. Then there is a big cylinder for the piston, a 1/2 inch oil feed/return hole and then 6 3/8 inch holes. 4 of those holes line up nicely with 4 little valves on the cap plate. the last two of those holes when inspected closely are machined with round "cups" that match the ball bearings. I put it all together, filled with oil, pumped the piston out, reopened the oil fill hole, put more oil in it and then, the piston came down!

It works great. What i did not understand at all with this is that this gear pump acutally pushes the cylender in both directions. Hence, it needs oil on both sides of it. I though that it pushed and then 'pulled' it back.

A buddy of mine was a heavy machine operator for years and explained it to me. I am amazed at how this simple machine can produce that kind of lift.