ensure
th.lt no one c.ln f.rll down an open lift shaft. Doors
on the ccl[e r']sureth at no passenqer c.rn be ir-r.iurcbcyl contact
with thc shzrft.T he car cannot move ut-ttibl oth sets of cioors are
closecl. Finally, at the bottont of the sh;rft there are largc. shocl<
absorbers, or buffers' to cushion the iÍnp.lcto f ;lny fJ||.A ll thesc
things comtrineclm