  A symmetry breaking mechanism is shown to occur in an array composed of
symmetric bistable Lorenz units coupled through a nearest neighbour scheme.
When the coupling is increased, we observe the route: standing --> oscillating
--> travelling front. In some circumstances, this route can be described in
terms of a gluing of two cycles on the plane. In this case, the asymptotic
behaviour of the velocity of the front is found straightforward. However, it
may also happen that the gluing bifurcation involves a saddle-focus fixed
point. If so, front dynamics may become quite complex displaying several
oscillating and propagating regimes, including chaotic (Shil'nikov-type) front
propagation. Finally, we compare our results with different couplings and with
other discrete bistable media.
