ATM Another version of Virtual Spring Counterweights??

["Shankland, CDR-Paul" <CDR-Paul.Shankland@cnet.navy.mil>]

Hi all, now that I'm finally in a position to continue virtual
counterweighting, I began a Krajci system that seemed a bit cramped on the
side of my 8" (f/8 - ie perfect for this application) travelscope). So I
moved the springs to the front of the rockerbox, merely "re-pointing" the
pulley, as it takes the cable from the ALT trunnion attachment point, to go
across the front rather than aft along the rocker side. I also began to
think, why not just use one heavier spring and attach the cable off EACH
pulley to EACH end of a bigger extension spring (rather than tacking down
the back end of two springs). This may both reduce space AND may even out
lateral forces (much like Nuatilus machines do say, on arm curl machines,
being independent yet lifting one weight). Not sure if I should double the
spring coefficient or double the spring length on the same coefficient
(which would make it match the two-spring system); I'd rather just double
the coefficient. But I'm unsure - anyone suggest ideas or thoughts on this?
One tougher spring in a support tube on the front could be handy...

Also, having just put up a new garage door using a torsion spring, this
whole counterweighting seems similar to garage doors to me.... Tom's method
is like two extension springs; yet one might also use a torsion spring,
which twists/wraps up its coils tighter to create torque. I THINK using this
one has the advantage of compactness and more travel before deformation, but
I'm unsure.... A torsion spring may be make-able with a coil spring slipped
over a support rod within. You would not need the pulleys, attaching the
cable directly to the end of the spring. Not sure if this is of any
advantage? Any thoughts?

I tried some ASCII art, we'll see if it survives the emailing! I sort of
exploded the Rocker sides out, to each side (3-D is impossible in ASCII!!
-grin-), and one is looking at the front in each case, FWIW.

 
Extension Spring Version of Front-sprung counterweighting:         
 
Pivot----------o     <- ALT Trunnion Attach ->   o--------------pivot
  Rocker     |                                               |   Rocker
       side    |           ROCKER FRONT           |   side
                 |  <-Cable                    Cable ->  |
                 |              __________                |
      Pulley  \o______/\/\/\/\/\/\/\/\/\/\_______o/  Pulley
                                 ___________
                       Extension Spring in  Support Tube



Torque Spring Version of Front-sprung counterweighting:    

Pivot----------o     <- ALT Trunnion Attach ->   o--------------pivot
  Rocker     |                                               |   Rocker
       side    |           ROCKER FRONT           |   side
                 |  <-Cable                    Cable ->  |
                 |               __________               |
no  Pulley  \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/  no pulley
                                 ____________
                             Torque Spring in  Protection Tube
                     Wound/coiled about support rod


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++=

Any thoughts or suggestions are appreciated, before I commit to one idea or
another!
Clear Skies!
Paul

Best wishes, 
Paul Shankland 
CDR, USN, Executive Officer, Jet Training Squadron NINE 
Norfolk VA (after 3 Nov, Meridian Mississippi) 

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