GTO 46 swing arm problem

[KGM]

Hello all, just having an issue on my GTo single colour.

5 of the swing arm grippers wont take the sheet, the outer 3 are ok its the middle ones that wont grip. running a3 is fine, but portrait a4 wont work. the sheet is just left on the feeder. everything else seems fine. this just happened, was working fine yesterday.
any ideas? im stumped

 

[alibryan]

Hello all, just having an issue on my GTo single colour.

5 of the swing arm grippers wont take the sheet, the outer 3 are ok its the middle ones that wont grip. running a3 is fine, but portrait a4 wont work. the sheet is just left on the feeder. everything else seems fine. this just happened, was working fine yesterday.
any ideas? im stumped

Aren't those grippers spring loaded? If it's what I think it is, solvent (to free up the shafts) and then some light lubrication should get them working again. You might do the same to all of them as where one or more are getting sticky, they're probably all getting that way.

 

[junker1984]

Agreed. First and cheapest route I'd suggest.

 

[junker1984]

Something I remembered from years ago...I was at a printer who was experiencing the same problem, and I could not free up the grippers. Lubricant was not breaking into the etch and chemistry that was seizing up the gripped bodies. Ended up using water to break loose the grippers. Maybe use a water miscible wash or go at it with warm water, but obviously, be careful and lube everything well afterwards!

 

[exheidmech]

To put it simply, yes, you may get lucky and your issue can be fixed with freeing up a few stuck grippers. This likely will only buy you some time before you need to rebuild your infeed. likely the gripper shaft on the swing gripper is bad and the gripper operating lever is worn out. Ive seen it tons of times and have done this job more times than I can remember. This really is only your permanent fix. Not a super costly repair, and once done your infeed will be good as new for years to come...guaranteed. What happens is that the 3 bearings on the swing gripper never get greased, water from the damping unit above will drip onto the swing gripper getting into the un-greased bearing which is especially bad on the drive side where the cam follower is. The load on this bearing and shaft on the drive side from opening and closing will in time wear into the shaft. This will cause the grippers to open less over time making it more and more difficult to run thicker paper.

 

[KGM]

thanks everyone, think ill have to get my engineer in.
lubricated it quite well and left it over the weekend. still the same.

 

[alibryan]

With the grippers in their closed position, you should be able to individually pull one open and then release it and it should 'snap back' closed again. If it doesn't, the grippers are sticky. Try some kind of solvent or alcohol and clean each one out until they do. You can do this by squirting some cleaner on the shaft and then pulling the gripper open and closed while you do it until the gripper moves freely. If and when it finally does, try not lubricating them at all and just turn the press on for awhile and let them open and close while the press is in motion. This will continue to free them up even more and should solve your problem.

Since the grippers open and close individually, I think this may be a different problem than was mentioned previously in this thread and it has nothing to do with a worn out shaft. If the shaft is worn out, none of your grippers will operate correctly, and you mentioned that some of them still do.

I ran K-line presses and GTOs for years and solved this issue more than once. If it's the same problem I was having, you can absolutely fix it yourself.

 

[junker1984]

This oughta be good

 

[exheidmech]

This oughta be good

lol

 

[KGM]

With the grippers in their closed position, you should be able to individually pull one open and then release it and it should 'snap back' closed again. If it doesn't, the grippers are sticky. Try some kind of solvent or alcohol and clean each one out until they do. You can do this by squirting some cleaner on the shaft and then pulling the gripper open and closed while you do it until the gripper moves freely. If and when it finally does, try not lubricating them at all and just turn the press on for awhile and let them open and close while the press is in motion. This will continue to free them up even more and should solve your problem.

Since the grippers open and close individually, I think this may be a different problem than was mentioned previously in this thread and it has nothing to do with a worn out shaft. If the shaft is worn out, none of your grippers will operate correctly, and you mentioned that some of them still do.

I ran K-line presses and GTOs for years and solved this issue more than once. If it's the same problem I was having, you can absolutely fix it yourself.

the grippers close alright just not enough to grip the sheet. is there a way to bring them on a bit without taking out the swing arm?

 

[exheidmech]

Its impossible to tell what was already done to the swing arm in an online forum. Can you simply readjust the grippers and everything be ok, possibly. You can try to bring the swing gripper into a position where the grippers are just closing and adjust each gripper yourself so that each gripper has slight drag on a sheet of onion skin paper. But when you say you have frozen grippers that tells me there is more going on with the swing arm. If someone has aleady tried to play with the grippers or the pretention it is nearly impossible to get it right by just adjusting the grippers. If you have already tried freeing up the grippers with no success than my thinking is to pull the swing arm. Bench setting the swing arm is the only way to get things back to factory specs in my opinion. Whatever you do, please lubricate those grippers and all grippers on the press. Dont use WD40, use a lubricant or penetrating oil. Not lubricating your grippers is not going to free up anything, lets face it, lack of lubrication quite likely got you into the position your in. Use lube. If lubing and adjusting the grippers doesnt work, your going to need to have a qualified tech pull the bar.

 

[KGM]

Its impossible to tell what was already done to the swing arm in an online forum. Can you simply readjust the grippers and everything be ok, possibly. You can try to bring the swing gripper into a position where the grippers are just closing and adjust each gripper yourself so that each gripper has slight drag on a sheet of onion skin paper. But when you say you have frozen grippers that tells me there is more going on with the swing arm. If someone has aleady tried to play with the grippers or the pretention it is nearly impossible to get it right by just adjusting the grippers. If you have already tried freeing up the grippers with no success than my thinking is to pull the swing arm. Bench setting the swing arm is the only way to get things back to factory specs in my opinion. Whatever you do, please lubricate those grippers and all grippers on the press. Dont use WD40, use a lubricant or penetrating oil. Not lubricating your grippers is not going to free up anything, lets face it, lack of lubrication quite likely got you into the position your in. Use lube. If lubing and adjusting the grippers doesnt work, your going to need to have a qualified tech pull the bar.

we only have the press 2 1/2 years, never had a problem with it, i do maintain it quite well and it gets a lube and oil regularly. swing arm hasnt had any work done on it as long as we have had the machine. maybe i havent maintained that section as well as i could have.
i loosened the allen bolt on the middle gripper from the delivery side just to see could i bring it on a little bit but it wouldnt move. its a bit dirty, id say it'll have to come out.