We analyze the global symmetries of $$ \mathcal{N} $$
N
= 4 supersymmetric mechanics in- volving 4n-dimensional Quaternion-Kähler (QK) 1D sigma models on projective spaces ℍHn and ℍPn as the bosonic core. All Noether charges associated with global worldline symmetries are shown to vanish as a result of equations of motion, which implies that we deal with a severely constrained hamiltonian system. The complete hamiltonian analysis of the bosonic sector is performed.