Heidelberg Windmill Gripper’s not gripping (Now With Pics!)

Hard to say not seeing the gripper arm setup first hand.

A couple of possibilities, original rubber is worn and glazed beyond it’s ability to perform properly. If so, I have in the past, taken double sided carpet tape and very thin rubber sheeting (thickness of 1/64th inch approx.) Clean existing surface of both blades on the inside, where paper is gripped, with wash. Dry it and clean with lighter fluid, to remove wash residue, for good adhesion. Do the same to the rubber sheeting being used if need (test small area first - may have to switch to rubbing alcohol as a residue remover). Apply double faced tape to rubber. Using a sharp razor, cut the strip to be used to the appropriate width. Gripper open and machine off and locked out - apply your creation to the sharp bottom blade precisely -to it does not protrude out from the blade at all. Cut out indentations and register finger holes with a sharp exacto knife or similiar. If turnbuckle that closes blade to proper grip has been adjusted to compensate for the worn original rubber, it may be necessary to loosen it slightly this part I am not very familiar with so won’t go there to much. I personally never adjusted the turn buckle after.

Definitely, without question, mark the blade you have worked on with a marker, for future reference. Definitely, roll the machine over by hand for the first few revolutions to check for tolerance, concerning this work, before operating.
Any protruding rubber or stray adhesive, sticking out will not be good, so be aware.

If you are in desperate need to do a job, and don’t have thin rubber sheeting and the store is closed. Try a couple layers of masking tape (no carpet tape needed) temporarily to (get the job out). Masking tape will eventually loosen and travel. Doesn’t provide as good of a grip as the rubber.

Good practice to count fingers before starting and when finished. Good luck, use caution.

Updated. Ok, I tried the rubber and carpet tape. Seems like it does increase grip on the arm that is working. The problem is the improperly working arm has so little grip area, that the rubber isn’t making a difference. My conclusion is that the arm is bent, but I attached a pic above so those with more experience can hopefully share their opinions.

Here is another pic:

http://www.oslopress.com/images/blog/WindmillGripper2.jpg

Why don’t you try to run it without the cheaters. You don’t really need them unless you need to steal an extra 6 pts from the gripper bite, or if you have the side guide adjusted all the way in.

If you want to check for a bent gripper arm, manually cycle the press (by pushing the flywheel) until the entire gripper is laying diagonally across the platen. Then take a scrap of paper and run it back and forth between the gripper and platen. There should be even drag on the paper, the entire length of the gripper.

I took the gripper off, bent it back to match the other gripper, and reinstalled it. It’s working fine now with the cheaters, things are registering and everything looks good so far.

Got the C&M working again too, but that was a bit messier (Piece of metal pipe over what was left of the old lever arm)

Glenwood - Although it does seem as though the bent arm was the problem in this case, in the future, you might consider using some long 2-point leads mounted with double-stick tape to give you a 3-4 point ‘cheat’ instead of using the standard heidelberg 6 point cheater bars.

Thanks to all for this post I was having same problem with one gripper arm , once I read this I bent it back and problem solved … Cheers

Something that I don’t believe was mentioned…is the back of the feed table at the same angle as the gripper? If the back of the feed table (part that has the separator fingers) is not even the sheet will come up crooked so one side of sheet will be farther out than the other side Hope you can understand this. There is a pointer at the bottom that should be at the 0 mark. It can be adjusted by loosening the two big bolts that hold the feed unit at the bottom. Ron

After checking back through the original comments I saw that it was just one gripper that had the problem, so it wouldn’t be the back of the feed unit as I commented above. Ron

I have the same problem too. But, is very hard to find carpet tape in Malaysia. Is there any alternative to carpet tape? And where can I get thin rubber sheet? Thanks.

Before you tape the gripper, you might want to make sure the gripper is not bent: it should line-up parallel with the sucker-bar at pickup and line-up parallel with the platen when the press is almost closed.

A good slow-motion shot of pickup can be seen at 1:40 in 100Original’s jazzy video:
http://vimeo.com/65293057

pickupScreenshot.jpg

I have took out all the tape and clean the residue. Is it possible to remain clean without tape on the gripper bar? I can pick up the paper with no problem now even though without the tape.

Depending on the stock, tape might not be needed.

I’d look for any marks on the stock from the grippers; the steel edges can be sharp and mark the stock. Tape or rubber sheet can help reduce marking.

I got a mark on my stock, I think I will have to put a tape on the gripper. The local printer here use light sand paper with double sided tape and stick on the gripper. I not sure whether this is an appropriate way. I am reluctant to try that.

If the gripper is holding the paper tightly enough, I would try just some tape to reduce the mark on the stock.

Where can I get 1/64 thin rubber sheet? For my windmill gripper.
Thanks.