\version "2.10.20"

global = {
  s1
  \once\override Staff.BarLine #'transparent = ##t
  s
\bar "|." }

rechts = \context Staff \relative c'{
  \context Voice = "rechts"
  s1 s
}

links =  \context Staff \relative c{
  \context Voice = "links"
  s
}

\score {
  \context PianoStaff
  <<
    \context Staff = "up" << \global \clef violin \rechts >>
    \context Staff = "down" << \global \clef bass \links >>
  >>
}