Rule 4401. Motion for judgment during trial. Any party may move for
judgment with respect to a cause of action or issue upon the ground that
the moving party is entitled to judgment as a matter of law, after the
close of the evidence presented by an opposing party with respect to
such cause of action or issue, or at any time on the basis of
admissions. Grounds for the motion shall be specified. The motion does
not waive the right to trial by jury or to present further evidence even
where it is made by all parties.