MV-JR knock out Cylinder

[markdel]

I have been having trouble with the air and oil knockout cylinders on 2 of my juniors. I have 3 that have never given me a problem and 2 that wont stay running. Even bleeding the hydraulic evry morning doesn't help. When the cylinder doesn't knock the tool out fast enough the tool change arm slips off and all kinds of bad things happen. Unfortunately there is no real way of seeing it coming before it happens. We have bandaided the problem in the past but a failure can cost up to $1000 to repair. I've had the cylinders rebuilt made sure the air pressure is correct. My distributor that supplies service for them is fairly stymied also.Does anyone know the fix or even better is there a retrofit available.

[RRL]

Have you checked the knock dimension? I had this type of problem a few years ago and increased the knock to .030".

RRL

[underthetire]

No retrofit I know of. VERY early ones had a check ball in line for the oil. The check ball seat wears out. This type would have an external oil tank. Other issues are bad spindles. If the spindle gets hot it will sweat the tool in over night and give you all sorts of headaches in the morning. Normal tool Knock out is .02-.04.
Newer type has a "Lucifer" valve on the front of the cylinder. Looks like ( and it is) a solenoid on the base of the unclamp cylinder. Those do go bad and leak. This will cause the unclamp pressure to drop, especially in manual tool unclamp.

[nakatome]

hi has any one checked draw bar tension if bellville dish spring are dry no grease or broken will cause the release to be slow and stick

nakatome

[Ziggy at RTM]

I am having similar issues. It seems the adjusting end of the knockout cylinder has actually come down and tightened itself against the spindle, causing the spindle to be tight and blowing a fuse (hopefully nothing more). I can't seem to adjust it back up, as the entire piston rod just turns. I have even tried jamming the locknut up against the cylinder body, but it still doesn't lock the piston rod.

I am also having a little trouble figuring out the air over oil in this cylinder. It seems the upper chamber is fed both air and oil? Or is there some sort of distribution channel in the center block of the cylinder? I am still in the process of removing the cylinder, and hopefully it will become clearer as I disassemble....but any insight would be a great help

[underthetire]

Originally Posted by Ziggy at RTM I am having similar issues. It seems the adjusting end of the knockout cylinder has actually come down and tightened itself against the spindle, causing the spindle to be tight and blowing a fuse (hopefully nothing more). I can't seem to adjust it back up, as the entire piston rod just turns. I have even tried jamming the locknut up against the cylinder body, but it still doesn't lock the piston rod. I am also having a little trouble figuring out the air over oil in this cylinder. It seems the upper chamber is fed both air and oil? Or is there some sort of distribution channel in the center block of the cylinder? I am still in the process of removing the cylinder, and hopefully it will become clearer as I disassemble....but any insight would be a great help

Can't help without details. There are at least 3 unclamp designs on those I know of. Please specify year of machine and post a picture.

[schmidtmotorwor]

I am also having a problem with my 1984 MV JR tool eject. It is very weak and sometimes won't eject.

I took the plug off of the top of the aluminum cylinder that seems to be air/oli and noticed that the air pressure is low and slow. There is some sort of regulator next to it and cranking that down did increase the force a little but not much.

I checked the air pressure coming out of the oiler where air connects to the machine and the flow is much higher. I wonder if there is a filter or something that can be clogged?

Has anyone solved this problem?

[andyhol]

I am having what sounds like some of the same problems, have been working on the machine and have come to find out that during the manual tool change the release cylinder releases fine, but during a ATC the cylinder does not travel enough and the arm yanks the tool or the tool falls out.

Currently my thoughts are that I let the oiler run dry and the cylinder is not moving fast enough for the time allotted. So I have put some oil in and shot some wd40 in the air lines at the manifold, but it does not seem to be helping.

Any thoughts?

BTW, to adjust the length of the cylinder end, there is a lock nut on top of the piece that presses against the spindle. Take the belt off, pull the spindle motor out some and you can get a wrench on the top lock nut. BTW again, unless someone has a smarter idea it is easier to pull the spindle out and adjust it with a socket and a wench.

Andy

[underthetire]

Are these cam type ATC or the old rack ones ? Sounds like you need to bleed the system. They use air over oil in MANUAL unclamp only if its the cam type. Cam type has a piston in the atc that pushes hydraulic oil to release the tool in MDI/auto. You should see a small black hex fitting sticking out next to the unclamp cyl. with a small tube and a set screw on the end. IN AUTO OR MDI only, crack the screw and watch for bubbles coming out of the tube. Close the fitting, go to manual, to a few manual unclamps, go back to mdi and do it again. You may have to do it a few times. Some machines have a pressure guage right above the ATC with a green area. You want to bleed it till it gets to that. If it keeps loosing bleed, you may need to change the lusifer valve on the front of the unclamp cyclinder. If those leak, it will force air in to the system during auto tool change.

[andyhol]

Originally Posted by underthetire Are these cam type ATC or the old rack ones ? Sounds like you need to bleed the system. They use air over oil in MANUAL unclamp only if its the cam type. Cam type has a piston in the atc that pushes hydraulic oil to release the tool in MDI/auto. You should see a small black hex fitting sticking out next to the unclamp cyl. with a small tube and a set screw on the end. IN AUTO OR MDI only, crack the screw and watch for bubbles coming out of the tube. Close the fitting, go to manual, to a few manual unclamps, go back to mdi and do it again. You may have to do it a few times. Some machines have a pressure guage right above the ATC with a green area. You want to bleed it till it gets to that. If it keeps loosing bleed, you may need to change the lusifer valve on the front of the unclamp cyclinder. If those leak, it will force air in to the system during auto tool change.

Are you serious is this operated by the actual ATC and not by the solenoid? How would I tell? I do see what I believe might be a bleed port, it is up on top next to the accumulator(?) with the site glass; is that the bleeder that you are talking about?

Now I am going to ask the stupid question, you say in auto/mdi only, crack the bleeder and then close it, should I give the command for tool change?

Andy

[underthetire]

If it's a cam type, yes they are unclamped from the ATC. air/oil in too slow to react in time. Bleed port is on the unclamp cylinder usually. Do not command a tool change, just break open the bleed port in MDI mode ( it shuts off the air solenoid). Once you crack it, close it, go to manual unclamp and cycle a few time, then back to MDI and repeat until the pressure gauge shows correct or there is no air coming out. Just like doing brakes on a car.

[andyhol]

Originally Posted by underthetire If it's a cam type, yes they are unclamped from the ATC. air/oil in too slow to react in time. Bleed port is on the unclamp cylinder usually. Do not command a tool change, just break open the bleed port in MDI mode ( it shuts off the air solenoid). Once you crack it, close it, go to manual unclamp and cycle a few time, then back to MDI and repeat until the pressure gauge shows correct or there is no air coming out. Just like doing brakes on a car.

You are a smart man, yes it is cam operated, but it tends to not work very well when the bearing is gone and part of the rod is gone.

Removed the two bolts that hold this assembly in but it seems to be set down in the mounting plate and hitting part of the cam above when I try and get it out.

Any ideas, thought,,, instructions :-)

Andy