ReChain positive locking mechanism

An energetic barrier against loosening of a connection.
There are many ways to do this both in basic principle and concrete geometry of design.

– Via cliplocks (may be energetically irreversible snapping or reversible silent opereatable)
– Via van der Waals force at nanoscale possibly simplifying designs (may be combined with commensurately interdigitating surfaces)

Concrete designs

Indexed nut locking mechanisms

How it works

Prototype of a positive locking mechanism: Here optimized for FFF 3D printing. Locked can only be while tooth index jumps for the nut. Here 1/13th of a revoution. With an FFF printing friendly big thread-pitch of 3.6mm this makes for a bit less than 0.05mm per notch (46.15µm). – Large pitch is also atoms-as-lower-size-limit friendly for future stiff gem based nanosystems.

Prototype of a positive locking mechanism: Here the printed parts are layed out in exploded view. Note that in the alternative case that the screw would have ho frlat "cut off" sides the toothed thick-washer/spacer part needs to lock to the underlying surfaces instead of locking to the screw. This can be naturally and elegantly done e.g. via a hirth joint. No cutoffs from the screw would be natural for nanoscale strained shell helical structures). (wiki-TODO: Add another graphic with arrows / numbers / text … to the pic)

The lock-ring gets pushed up by a spring onto the nut. (Red TPU rubber in pic.)
Thereby reliably preventing the nut from undesired turning and loosening.

The lock-ring is prevented from rotating by rotationally locking to the
(in pic obstructed) spacer below the nut which in turn locks to flat of the screw.

Alternatively the spacer could lock to the the base via a RC/HirthJoint interface.
This seems even better because it does not depend on a flat screw.
(small diamondoid nanoscale screws can't really have their sides cut off)

(TODO: Things to improve from this first prototype: …)
– clearance need to be be given not only radially with a cycloid profile
– spring needs improvements: more clearance, more sturdy, make it twist instead of bulging
– earlier nuts where to weak but this one is too beefy – fatter screw or thinner nut?
– change the spacer to lock to base via a Hirth joint interface rather than locking to the screw

Usage

Example usage here as a connector fro parts manufactured (printed) in different orientations. Related topic: Benefits of post assembly over in place manufacturing.

The idea is to avoid using the screw directly for tensioning to:
– avoid application of high torques to the structure
– avoid the necessity to either transmit high forces or complex big gearing mechanisms at an end-effector

{{wikitodo| add scan of paper sketch here …}

This hall work as follows:
– a second nut B in a tool/end-effector gets screwed onto the screw (pushing back the lock-ring)
– a nonlinear high leverage double hinge mechanism pushes screw B and lock-ring (or better base) apart
– …

For details see: ReChain force hydrant

Clip on indexed nut locking mechanism

(wiki-TODO: Add image and description. Pros & cons.)

Related

• ReChain
• ReChain tensioner
• ReChain force hydrant
• ReChain core chain

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• List of machine elements

External links

• https://en.wikipedia.org/wiki/Positive_locking_device