In this work, we propose a contact point localization and external force estimation algorithm for collaborative robots. In comparison with existing approaches, the proposed algorithm can detect and evaluate multiple solutions and more than 3x faster without loss of accuracy. To achieve real-time performance, a hierarchical robot representation and surface mesh preprocessing was used, allowing us to achieve a 50x speedup in a run-time, compared to checking all contact points. Mesh preprocessing includes two-step clustering in the space of vertices normals vectors and vertices positions. The localization method was tested in a simulated Kinova Jaco 2 and real KUKA iiwa LBR 14 collaborative robots. Our solution allows estimating the contact point on the robot surface with 2.3 cm average accuracy in a more than 600 Hz loop.