friction is considered viscous and not dry.

The first case, when the pendulum clocks are suspended at a very rigid house beam, therefore not able to move, has been approached in the works [@Abr2; @Abr; @Vass]. In this model the interaction is considered perturbative. When one of the pendulums suffers the internal impact from the clock escape mechanism, a small travelling wave perturbs the second one and vice-versa.

Recently, in [@OlMe] a theoretical model for this interaction was developed. In the same work, simulation and some experimental studies were carried on, that confirmed the validity of the proposed model when the support wall has infinite mass and, therefore, not moving. Naturally, the center of mass of the wall is not, in this case, a degree of freedom of the system and the coupling is, via very weak travelling waves, propagated in the rigid structure of the wall.

In this article, we use as a conceptual starting point [@OlMe] presenting a mathematical model where the coupling is assumed to be attained through the exchange of impacts between three identical oscillators, where each one of the clocks interacts with the two other clocks. The model presents the advantage of being independent of 