ReChain panic snap

Usage as an element in overload protection

The idea here is that if a certain level of load is exceeded the a panic snap self-opens via some (as simple as possible small but crude) integrated load measuring mechanism. So rather than gradual overload damage or even catastrophic instant fracture there is an opening event at a precisely defined location. The event will still be energetic as it converts the potential energy in kinetic energy that the surrounding structure needs to absorb.

See:

• ReChain overload protection against excessive tensile load.
• ReChain intended breakage point

Usage as easily (robotically) operable dis- (and re-) connection mechanism

This is a mechanism that allows to rapidly disconnect a mechanical coupling
by pulling (at the right spot) in the same direction that one wants to disconnect. E.g. pulling a strut from a node directly away. Just pulling at the right spot is a very easy and trivial way to operate/actuate a connection. Thus it is of interest for ReChain robotic manipulation. (The ReChain force circuit needs to be released of its ReChain pre tension first though.)

Reconnection can be a bit less trivial
as one needs to pull (at the right spot) while pushing (e.g. the strut into the node).

Variants of the panic snap principle can make the reconnecting process trivial though at the cost of a energy dissipative click.

Fir tree quick disconnect - variant of the principle

See page: ReChain fir tree quick disconnector

Related mechanism

An interesting related mechanism is the snap-shackle.
It too features a massive ratio between holding force and actuation force.
Not as much as the panic snap though. And the direction of load and the direction of actuation are not parallel/collinear.

Here:

• actuation motion is not parallel to the load force (making actuation possibly more difficult) — and thus also
• higher load means higher friction resistance against actuation (but still a small resistance)

External links

Wikipedia

• https://en.wikipedia.org/wiki/Panic_snap
• https://en.wikipedia.org/wiki/Shackle#Snap_shackle

German

• https://de.wikipedia.org/wiki/Panikhaken
• https://de.wikipedia.org/wiki/Sch%C3%A4kel

Related

• ReChain
• ReChain overload protection
• ReChain intended breakage point
• ReChain fir tree quick disconnector
• ReChain strut & ReChain node

Page history

Page first created 2020-06-13 Saturday on local wiki.