It should be possible to setup a test for this. put a bolt in any sort of
anchor, put the sled in a fixed position (or even have an anchor on the other
side), extend the belt to the anchor, measure, re-rig the belt end with the
extension (which needs to be solid enough to not flex under load) and retract
the belt until it’s tight and record the difference.
David Lang
Received 8 ft fiberglass ladders via Walmart for $108 each. I like the ladders. Previously bought emt conduit for another idea. I figure attach conduit to back side of front section of ladder with cunch velcro straps. Usinf 4 total on front. It is about 3 1/8" from bacl of front section to front of leg. Plan on torsion boxes that can be unstalled on conduit. Instead of entire 4x8 ft torsion box. I am thinking 4 boxes 2 ft by 3 ft. With the sled able to travel 2ft 7in on 3 ft leg. Plan to have track in 5 inch area for cla.ps to edge where needed in case of loss of vacuum. Fuguring .5 inch underlayment should be ok for disposable underboard. So these boxes will sit up and down on each side. Think 0.5 in underlayment at 65 degrees should.not sag much but bracing could be added if eeded. I am new to this. Comment welcome.
Can we get a closeup pic of the end of a belt as that will influence the design of the frames I expect. If it’s a flat plate with a hole for a pin then would be good to understand the geometry so frames can be planned in advance.
it’s more like a tube that the belt wraps around, with a bolt going through the
tube into the frame (based on the little that I’ve been able to see from the
pictures).
that seems logical to me, easier to attach to the belt, stronger than a flat
plate that would need to sit at right angles to the belt, and a larger surface
area against the bolt (less wear over time). The tube is also an easy thing to
handle when retracted against the sled.
David Lang
It’s a 10mm hole because 10mm is close to 3/8th inch, but we will probably offer a couple different sizes because I can imagine that for different frame designs something different might be ideal. They don’t have to be this shape either so we could offer some different designs if that’s something that’s useful.
EU/UK based means 10mm is perfect as it’s off the shelf for bolts and pins etc
yep, 10mm and 3/8 are both common and the differnce between them isn’t going to
matter for this sort of use case.
David Lang
An alternative to knowing the carabiner size precisely would be to select a range of extra length to get in the ballpark, then precalibrate by touching off on a circle of known size. Perhaps a circuit board taped to the spoilboard could be the precise circle. A 555 circuit and 2032 battery on the circuit board produce a signal that goes away when the touch probe leaves the circle.
The touch probe could be a length of straight wire, or standard pogo pin inserted into a router collet.
