Delivery Gripper Problem

Hi Guys,

I am facing problem with running the press to a speed of 9000 iph.... Its an old SM 102 1987.... Problem i have is that when i run the press at speeds over 8000 iph ,
2 of the gripper bars drop the paper form D/S. I've checked the gripper settings on these bars and looks ok to me,
Can it be the bad cam follower or the pin that holds the cam follower bracket...

 

Aqazi,
are you referring to the delivery grippers? Its not unusual for delivery grippers on a press that old to require a rebuild. At what point are your grippers dropping the sheet? If their being dropped as the last unit impression cylinder is handing it off the the delivery grippers it could be as easy as adjusting the cam. If i remember correctly the cam can be found on the operator side of the press just in front of the last unit impression cylinder. You will find the cam slotted so that it can be timed. If thats your problem then just loosen up the locks and slide the cam a bit to adjust timing. Just be sure to mark your position with some whiteout before you move anything in case to have to put it back to where it was. If its in fact where the cam followers on each gripper bar are pinned there are guys out there that can rebuild the delivery grippers. I dont think a press that old would be worth installing new gripper bars but a rebuild would add years of life to the press.

 

Yes TT a rebuild is much cheaper here than replacing with new ones...
But if it was the cam problem than it should happen on all gripper bars instead of two.

 

aqazi - If you can pinpoint which of the six gripper bars are not releasing properly, you may try resetting the individual grippers on each of those bars, the setting procedure is as follows:
fully turn in 3mm set screw
loosen the clamping piece and and rotate gripper away from pad (spray with lube if sticky, if too tight to turn, back off set screw slightly)
insert 4mm between gripper and pad, lock up clamping piece
insert incised value (i.e. 55 means .55 mm, 70 means .70 mm ) between lever and tube
set individual grippers starting at OS to an even light drag using .03 to .1mm paper slip
If this procedure does not remedy issue, you may have an offset (bent) taper pin in cam follower lever, you must remove gripper bar to knock taper pin out, replace if bent. If you cannot knock pin out, you will have to drill out, another possibility is that it is fully sheared, in which case you will have to drive the lever off the tube laterally. Lots of info here, hope you will only have to reset the grippers.

 

Thanx mqgpress....I'll try this...

 

Aqazi - As you mentioned in your original post, be sure the cam follower is not loose on the pin.

 

aqazi,
the cam adjustment i mention might still work to compensate for a couple of worn grippers if in fact your dropping sheets at that transfer point. I suggested this in the event that wear issues were causing the problem. This might give you a little more time until a rebuild of the grippers can be done. It might also compensate for some wear in the followers or even cam lobe

 

@TT you are right.....But which way to turn the cam??? Up/Down?

 

aqazi without it being right in front of me to see i cant remember. I suggest sending a long stream of small sized sheets through the press till they get close to the final transfer. Mark the cams current position with white out and then move the cam a small amount and tighten it up. then jog the press until the sheets get to the transfer point. at this point you may want to turn the press manually with the crank handle so you can move it in very small increments. Look to see how the impression cylinder hands off the sheet to the delivery gripper. You need to find the happy medium between dropping the sheet and tearing the sheet. It may take a few attempts to find the right timing degree but youll get it. The reason i suggest a small sheet is so you will have room to work. If it is infact causing your problem retiming the cam might just buy you some time till you can do a proper repair.
As far as identifying which delivery grippers are the problem i suggest putting the tape from the top of the ink cans on each gripper shaft. Start with black and then move on to blue on the next gripper. then go red, then yellow, then white ect. as the press is running count in your head.. black,blue,red,yellow and so on as you watch the grippers deliver the sheet. When you see a a bad one you will know how to identify it.

 

If you are dropping sheets, you must lower the cam to allow the grippers to close on the sheet earlier, as tt mentioned, it doesn't take much movement to make a big change in timing. I'd be surprised if the cam positioning was the main cause of the problem/

 

@TT... I've Identified the gripper bars and !st I'll set the gripper bars and then if the problem is still there, I'll move to the next step...as you mentioned the timing of the cam...
Thanx guys for your help...

 

If their getting alone as the bear crowd result butt is hand it off the supply grippers it could be as simple as adjusting the cam. If I bethink precisely the cam can be begin on the abettor ancillary of the columnist just in foreground of the endure assemblage result cylinder. You will acquisition the cam slotted so that it can be timed. If that you are botheration again just alleviate up the locks and go faster the cam a bit to acclimatize time.

 

Thanx guys for your help...the problem is gone by resetting the grippers.......

 

Say what LOL?

 

Lolz....

 

labelprinter would you care to tell us your feelings on the flux capacitor?

 

I think his feelings on the flux capacitor is what he was giving :O

 

the last time i let a bear get near my butt ihad to aclimatize my *** to the emergency room.