When is a door not a door? When it’s a trap for terrorists and would-be
thieves. Saima Sicurezza of Arezzo, an Italian company, has filed a British
patent application (2 253 224) on a revolving door that is also a security
check.
The door contains a pair of electromagnetic coils like those used in metal
detector gates at airports. If the detector senses that anyone inside the
revolving door is carrying a suspiciously large amount of metal, it triggers
a signal which slides a curved panel between the revolving door and the
entrance. An alarm sounds if anyone in the door tries to obstruct the
sliding panel.
Powered by a motor, the revolving door ejects the suspect out into the
street. Banks and jewellery stores could use it to protect themselves while
presenting a relaxed appearance.
