Deckel KF2 unloading spring disassembly

Hi All,
I realize this is a long-shot but it never hurts to ask before giving a best-effort and making a hash of a nice machine.

I recently acquired a Deckel KF2. Overall I'm very happy, the machine is in great shape, and came with the factory cabinet full of accessories. A lube job and belt replacement and its been good to go. My one complaint is that the unloading spring has settled over time, and you can no longer apply enough tension that the spindle will lift away from the work if you let go of the handle.

I'd love to hear from anyone that's tackled this mechanism before, or anyone that knows of any factory manuals describing disassembly of this mechanism.

Description of the problem:
The unloading mechanism is powered by a large coil spring in the casting base, attached to a rotating shaft in the top of the casting. There is a cam-lobe on the shaft, over which spring-steel strips are wrapped. The coil spring pulls on the free ends of these spring steel strips. The shaft connects to something inside the casting that I can't see to provide lifting force to the whole pantograph assembly(That mechanism should be visible if I remove the pantograph, but I've been avoiding that so far because its working beautifully). I think I can correct the low force issue by simply shortening these strips to increase tension on the coil spring. Interestingly I found some spare strips in the cabinet, so either someone has already replaced them once and kept the old ones, or they purchased parts to fix this issue and then didn't finish the job.

I think I need to unload the mechanism, and stretch the coil spring so the strips are not under load, and remove them through the small access panel in the machine front (roughly 6"x10"). The problem is I can't figure out how to unload the spring mechanism enough to get the strips untensioned. There is a preload-setting handle on the side of the machine, which will reduce the spring tension, but not eliminate it. I haven't figured a good way to preload the coil spring so I can remove the strips, and I've no access the bottom of the coil spring without hanging the machine overhead to get underneath the casting,and that idea gives me the heebie-jeebies. I've got the machine manuals and they do not mention anything about servicing the unloading assembly.

My best thought so far is to get some steel cable with turnbuckles, and use it to pull the coil-spring end up to the shaft, unloading the ribbons so I can pull them out. I'm sure that wasn't how the factory did it, and I'm hoping I've missed some clever way to service the machine.

Cheers

I don't know much about those machines but do have a manual for one, at one time I was going to buy one. After looking through that manual I realized how a couple of missing parts to an attachment might render it useless and finding them would be iffy if not impossible so I shied away.
Back to your original question with a question; Do you believe those steel strips stretched or is it more likely the spring has lost some tension over time? I'm not able to look at what they are but am trying to imagine them stretching enough to make a difference.
Dan

My first guess was the coil spring permanently stretching out slightly. The strips look like the steel pallet banding, but are made of spring-steel 1"wide. I'd be pretty surprised if those stretched any, but I don't actually know what kind of tension is on the mechanism. The pantograph arms have to weigh 200+lb, and there is a mechanical disadvantage at play, so I'd W.A.G. that the unloading spring is probably putting out 4-600lb depending on where the preloading is set?

The strips have little blocks clamped on the ends that allow them to be fixed in place, and I think it more likely that these have slipped, exposing more length than the strips themselves stretching.

I was actually just thinking this-afternoon that a cheap solution might be to make a little spring compressor and install it semi-permanently in the machine to compress out a few sections of the coil-spring to up the tension a bit. Definitely a jackass-lashup, but probably would give me the results I want.

Cheers