View source for ReChain fir tree quick disconnector

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{{wikitodo|Add images to illustrate the concept.}}<br>

[[Fir tree joints]] are generalizations of the more widely known dovetail joints. <br>
Fir tree joints are of interest as they preserve more of the original material strength. <br>
(Thus they are used e.g. in the roots of single crystalline ultra high strength turbine blades of jet engines.)

== Connector geometry and operation ==

The idea here is to split a fir tree (or dovetail) in the middle so <br>
the sides can be slanted in some angle in order to (dis)engage the connection. <br>
* Add two gear segments at the inner sides of the split up fir tree down at the base respectively
* Add a rack rack in-between the gear segments with an eyelet at the back 
* Add an elastic element that pushes rack-with-eyelet forward (thereby pushing the half fir trees apart to straight engaged configuration)
* Add an (in diameter matching) pin through the eyelet for actuating on it by hand or by robotics

This geometry gives the following nice functions:
* Pushing the male connector (out of two half fir tree prongs) into a female inverted fir tree receptor naively will result in a nice (macroscale satisfying) click-in connection. <br> At the nanoscale this click can be quite energy dissipative (wasteful). The click can be averted by pulling the actuation pin while inserting into the connection. Somewhat of a cost in robotic complexity here.
* Pulling on the (detensioned) connection won't open it as the fir trees may typically engage slightly barbedly. Pulling on the pin first disengages the barbing and only then pulls out the fir tree. But one only pulls on the pin. The transition beteen the phases happens by itself. (This needs to happen when the [[ReChain core chain]] is detensioned)

The idea in context of the [[ReChain]] system is to connect without system tension and then tension the system up.

{{todo|Make an actual 3D printed prototype of this!}} <br>
{{wikitodo|Post results of an evantually 3D printed prototype here.}} <br>

== Related ==

* [[ReChain]]
* [[ReChain panic snap]]
* [[ReChain connection mechanism]]
* [[ReChain special elements]]