  S. Satoh has defined a construction to obtain a ribbon torus knot given a
welded knot. This construction is known to be surjective. We show that it is
not injective. Using the invariant of the peripheral structure, it is possible
to provide a restriction on this failure of injectivity. In particular we also
provide an algebraic classification of the construction when restricted to
classical knots, where it is equivalent to the torus spinning construction.
