Windmill grippers and suckers synchronisation

Leo, try loosening the grub screw, loosen the bolt under it, then get a sheet in the suckers and stop it just before the gripper hits it, the turn the eccentric and watch the sheet, you will see it go into the gripper better. don’t worry about the grub screw, when the bolt under it gets tightened it will hold the eccentric in place. Dick G.

Thanks Dick.

I tried your suggestion adjusting the height at which the suckers meet the gripper. When the eccentric is turned and the suckers are the highest possible the sheet is sometimes picked up but still most of the times it is knocked off by the edge of the gripper closer to the suckers.

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Maybe you have a bent gripper, i’m about out of ideas, one of my windmills has a bent gripper, if you try to bend them they can break (been there done that). There must be someone near you that you could get to look at your press, check the yellow pages on this site. I have slid an iron pipe over my gripper and tried to straighten it, very little pressure, a little at a time or they will break. Sometimes i’ve just pushed with my hand on the end of a gripper if it has hit to hard on the die jacket. Dick G.

lishii;
Is it possible that the sucker bar isn’t coming up high enough? When you said about the bottom of the gripper hitting the paper loose it made me think that perhaps the sucker isn’t high enough. (not talking about the angle) I don’t know if there’s any way to adjust that. Another idea…..Do you have any thing at the trailing edge of the sheet to keep the sheet in place in case the blast is too strong. If too much air blast is hitting the sheet it might cause it to jump back (toward the operator). It wouldn’t take much movement. Ron

When the gripper bar is at the 6 o’clock and 12 o’clock position, about five inches from closing and the gripper bars are locked (no wiggle) see if the 6 o’clock gripper is lined up with the edge of the platen exactly. Take the jacket off if you are using one. If it is not, email me for instructions on resetting the gripper bar casting position.

Thanks Dick, I took off the grippers and checked that they are not bent.

Ron, the grippers are at the highest possible. Things have improved since, but they still knock off the suckers most of the sheets.

Linegauge, i think you are hitting the mark. The grippers don’t line up with the edge of the platen. I will send you an email.

lishii;
I’m not sure if you understood my last comment…was thinking more of getting the sucker bar to come up higher. Ron

Ron thank you for your suggestions. I think i do understand what you mean. The bar that holds the suckers, yeah, I managed to adjust the height thanks to Dick’s instructions. That has helped but it seems that the problem is to do with the rotation of the grippers. they come too close to the suckers no matter how high or low the adjustment of the eccentric.

I tested the grippers against my typesetting bench and they are surprisingly straight.

lishii;
When the gripper stops as the platen closes is it the same distance in relation to the platen? Just asking to better understand the problem. I know on our windmill the gripper is higher on the end farther away from the revolving mechanism. Ron

Thanks for the comment Ron. Oh, that is interesting. so, do you mean that your gripper stops at an angle (not parallel) to the platen? I thought that this was a discrepancy of the proper configuration of my windmill and that therefore it was a probable cause for the problem I am having.

On your press does the gripper stops closer to the suckers on the end that you mention as higher? what is the closest that the gripper should get to any of the suckers?

on mine at the moment the end of the gripper gets as close as about 4 mm.
leo

lishii;
Ok…let’s see if I can clarify this. If I lay the platen in a horizontal postion and look from the side one end would be higher. In your case if you looked down from above one end would be farther away from the side of the platen. Right? If that’s correct then I wonder if the shaft or gears in your revolving mechanism are the problem. Wonder if one of the gears might have skipped a tooth? Might involve taking that revolving head apart. Just an idea. Ron

Thanks Ron, it seems that that is what i need to try next. I will need to release the casting that holds the grippers using some instructions that Linegauge has sent me. I will need a few extra tools for this operation so it will need to wait until the weekend. I will post photos with the process.

lishii;
Let us know how it goes. Good luck. Never know when we would have the same problem. Ron

so, thanks to Linegauge, this is what i had to do:

took the gripper bars off and loosened the central bolt. Then used a rubber mallet to knock the casting that holds the gripper bars a bit. The casting started to move with a few hits. If the casting wouldnt have moved then there were other instructions that i didnt need.

The rest of the instructions by Linegauge were about pushing the casting back into position using two different methods. I used a bit of both.

hopefully this will serve as basic insight of what you will need to do if you are having this problem.

thanks again to everyone that contributed,
special thanks to Linegauge!
leo

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lishii;
Glad to see that it worked for you. For some reason I was thinking of having to take the under side of the housing apart, rather then going in the top. It’s a relief to see I was wrong! Thanks for your update. Ron

I just got a call from a printer with a very similar issue: the grippers are not stopping in line with the platen. (10x15)

The grippers are reported to be straight.

Q’s:
1) Is the shaft seen in the above picture a taper-fit with the carrier casting T1301? (wondering how it can hold alignment without a key)

2) If the alignment is close (~4 points off parallel at gripper tip), can the eccentric inside the head (picture below) be adjusted to align the gripper?

Thanks in advance,
AM

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The pawl shown above is to keep the gripper assembly from reversing and to ensure it has a positive stop point the adjustment makes little difference to the position of the grippers in relation to the platen in the case referred to earlier in the post .
At the top of the drive rod that enters the lower portion of the grippers shellhousing there is a sort of pair of collars they engage together with a sort of ratchet fashion the two collars that meet are toothed on the surface that meet ,there are many teeth and you may need to part the two collars ,advance or retard by one or two teeth and re assemble the drive ,this is not an operation for the faint hearted and the machine must be rotated by hand after adjustment never test under power …

Thank you for the reply,

The amount of additional rotation required is small, a fraction of a degree.

If the previous issue was resolved by a gentle rap, might this also, as the amount of change needed is less than half of the earlier example?