Mesh Falling Out of collider

Hi,
I have made a ragdoll-like character using hinge-joints in Unity3D. The Hierarchy of the character is:


I have attached RigidBodies to Robo, Right Shoulder Up, Right Shoulder Down, Right Elbow, Right Shoulder Hand(same goes for left side), for the legs: Torso, leg and shoes have rigidbodies.
The problem i am experiencing is that when the character falls from above, the meshes or the materials idk what, falls from their colliders. Any thoughts why is this happening?