Hidden German thinking: convertible top cover

[ksalzer]

I find the engineering in my 230sl endlessly fascinating. I was removing the convertible top cover yesterday (had some re-gluing to do on the MB Tex trim) and noticed something interesting. The cover has two arm-like hinges that disappear into the trunk when it's closed. The driver side hinge (closest to where the cover release lever is) has a spring attached to it that helps to keep it up when open. Interestingly the passenger side hinge has no spring where you'd expect one. I was pondering the reason for this and came up with some ideas:

1. Makes the car lighter ("super light") by one spring
2. One less part to worry about
3. Less cost - an extra spring could hurt your bottom line
4. The most interesting possibility: some German engineer figured that if there were two springs - one on each hinge - the hinges would open at slightly different rates (since your hand is guiding it on one side, but not the other), torquing the top cover, possibly bending it slightly over time, as if both springs would be fighting each other to open the cover. A perfectly aligned cover is essential as we know. If true, this is another example of less-is-more, behind-the-scenes German engineering that makes our cars kind of amazing.

I could be way off on my reasoning, so any other ideas on why there's only one spring?

Kris
1965 230sl
Grey beige / turquoise

[Tomnistuff]

Hi Kris,
Click on Technical Manual at the top of the page, scroll down to the Contents list, then click on Chassis and Body, then Trunk or Boot, then Softtopcover and Trunk Hinge Torsion Rod Removal.  There is a detailed description and marked up photos describing the function of the TWO torsion springs and hinges, and how they control the trunk lid and the soft top compartment cover.  It also teaches how to remove and install the springs and the tool I made to manipulate them.
I think weight, complexity, number of parts and left/right force distribution were not their worries.  I think they just wanted the two lids not to collide by mistake when opened at the same time.  It is ingenious, however.  While the soft top cover is open, open the trunk and watch the soft top cover close.  FUN STUFF.
Tom Kizer
Levis, Quebec, Canada

[MikeSimon]

I think your item (4) has the answer. And I don't think it is necessarily a "German" thing. If you have two springs actuating on the same thing, one spring will become redundant. The spring rates and tensions will never be able to be set and matched such as to apply equal force. The only time you want two springs is when you try to achieve a "progressive" action.One spring is "softer" or of a lower rate and will start actuating until a second spring of a higher rate will finish the job.

[ksalzer]

I know, right, Tomnistuff? Open the trunk and the convertible lid closes. Nice. Btw, nice work on the torsion spring removal tool!

[ksalzer]

Mike, makes sense!

[Alex D]

Hi Kris, Tom

Just curious, what color is your soft top?

Alex

[ksalzer]

Alex, my top is currently black, but I have a copy of the build sheet (requested from MB) and it was originally ordered with a *green* soft top. I do love the very unusual grey beige / turquoise combination - it was originally a Florida car, and it genuinely looks of that period and place - but those two colors plus green for the top? Glad it's now black!