Gripper Nicks

[Warren Peace]

Hello, I'm getting nicks in my paper from the delivery grippers on my 3302. It's because of some play in the shaft and I was wondering if anyone know how to fix that issue. Here's a link to a video showing the problem. Thanks!

 

[printerdan]

I think you can solve that by setting the particular gripper finger(s) to open wider; effectively opening a bit earlier to clear the front of the sheet.

 

[Warren Peace]

I really wish I could do that but there's a cam in there that opens all the grippers at once and the adjustment for them is minimal at best. I spoke to a mechanic today and he told me to do the job properly it would take him 6 hours and a press like that is not worth that much. It's because there are pins in there that are designed to break for safety reasons. After time they get weak from use and the problem only gets worse. I can either advance the whole gripper system a bit (allen screws on the geared sprocket) or weld the shaft and sprocket together (which is commonly done). I think I'll try the welding idea.

 

[printerdan]

Of the three gripper bars do some of the fingers clear the sheet?
Two cams open the bars; that which you noted and a second one for the sheet to fall. After the sheet is released the bar travels around and up. Immediately above that second cam the bearing has minimal clearance; you should be able to slide a nickle between the bearing and the bar which holds the cam. Make it a slim nickle. The bar is closed and at rest a this point and you can adjust the grippers individually. Trial and error; avoid error.

 

[precision1984]

How about this? If the “pins that are designed to break” are simply roll (or spring) pins, is it possible to figure out the proper dimension (diameter and length), and drive it in to replace old ones to restore some stability? There will be wear in the shaft, but often times not so much that you can’t realign and strengthen the assembly.

 

[FourFingerRing]

Not familiar with the 3302 gripper system. But make sure you dont have individual adjustments for each gripper on the delivery bars. If so open them slightly on the problem grippers. Also if you can tighten your chain for you delivery grippers, try that also, slop can cause grippers to not open correctly. If your maintenance guy can pull himself away from his coffee cup for a second maybe he can help. "that will take 6 hours the machine isn't worth that much".

No sheets through the press means no one has a job.

 

[Warren Peace]

How about this? If the “pins that are designed to break” are simply roll (or spring) pins, is it possible to figure out the proper dimension (diameter and length), and drive it in to replace old ones to restore some stability? There will be wear in the shaft, but often times not so much that you can’t realign and strengthen the assembly.

From what I was told, that is the proper way to do it but it requires hours of work in removing the parts to get to the pins, including sensors for timing. Welding the shaft to the gear is apparently a common solution for this problem and seems practical. I like your idea better though.

 

[Warren Peace]

I finally found my parts book. It seems to be a simpler job than I thought. I think I’ll try the proper way of fixing it. Famous last words...

 

[precision1984]

“Just Do It”...as is said. Use new roll in to drive out old. The only problem you may run into is if the old pin is fully cracked/broken and driving it out doesn’t work out, whereas you’ll have to realign the sprocket to shaft positioning in order to line up the mating holes. Good Luck! Really dig the “Warren Peace” moniker, by the way.

 

[realaqu]

I finally found my parts book. It seems to be a simpler job than I thought. I think I’ll try the proper way of fixing it. Famous last words...

loose screw 32, there should be 3 screws hold the gear, and move them towards inside a little bit, it is an old machine, the gripper open a little late

 

[FFR428]

loose screw 32, there should be 3 screws hold the gear, and move them towards inside a little bit, it is an old machine, the gripper open a little late

^^^^THIS! It's a small timing/eccentric adjustment on the non op side. It happens if the press had a good jam sometimes. No need to take everything apart. Easy!!