  We define and evaluate on the lattice the amputated 3-gluon vertex function
in momentum space.
  We give numerical results for $16^3 \times 40$ and $24^3 \times 40$ quenched
lattices at $\beta=6.0$.
  A good numerical signal is obtained, at the price of enforcing the
gauge-fixing condition with high accuracy.
  By comparing results from two different lattice volumes, we try to
investigate the crucial issue of finite volume effects.
  We also outline a method for the lattice evaluation of the QCD running
coupling constant as defined from the 3-gluon vertex, while being aware that a
realistic calculation will require larger $\beta$ values and very high
statistics.
