  Based on the Fokker-Planck equation we investigate the transport of an
overdamped colloidal particle in a static, asymmetric periodic potential
supplemented by a time-dependent, delayed feedback force, $F_{\mathrm{fc}}$.
For a given time $t$, $F_\mathrm{fc}$ depends on the status of the system at a
previous time $t-\tau_\mathrm{D}$, with $\tau_\mathrm{D}$ being a delay time,
specifically on the delayed mean particle displacement (relative to some
"switching position"). For non-zero delay times $F_{\mathrm{fc}}(t)$ develops
nearly regular oscillations generating a net current in the system. Depending
on the switching position, this current is nearly as large or even larger than
that in a conventional open-loop rocking ratchet. We also investigate
thermodynamic properties of the delayed non-equilibrium system and we suggest
an underlying Langevin equation which reproduces the Fokker-Planck results.
