We use a hybrid constituent-quark model for the microscopic description of $pi N N$, $pi N Delta$ and $pi Delta Delta$ vertices. In this model quarks are confined by an instantaneous potential and are allowed to emit and absorb a pion, which is also treated as dynamical degree of freedom. The point form of relativistic quantum mechanics is employed to achieve a relativistically invariant description of this system. Starting with an $SU(6)$ spin-flavor symmetric wave function for $N_0$ and $Delta_0$, i.e. the eigenstates of the pure confinement problem, we calculate the strength of the $pi N_0 N_0$, $pi N_0 Delta_0$ and $pi Delta_0 Delta_0$ couplings and the corresponding vertex form factors. Interestingly the ratios of the resulting couplings resemble strongly those needed in purely hadronic coupled-channel models, but deviate significantly from the ratios following from SU(6) spin-flavor symmetry in the non-relativistic constituent-quark model.
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