Mechanical turnstile

摘要

The gate consists of an arm fixed to a vertical shaft (2) mounted on a base containing a mechanism which allows the arm to turn in an opening direction, comprising a threaded section (8) on the lower end of the shaft, able to engage with a member (20) which can be fixed from rotation by a friction assembly (12, 14, 15). The rotation of the vertical shaft it limited by a projection (38) on the shaft's lower end which engages with a clearance in a slot in the fixed member (20). The gate has a mechanism which returns it to the closed position after opening, using the spiral threads on the lower end of the shaft or a return spring. The friction assembly allows the gate to be opened in the reverse direction in an emergency and locating pins enable it to be re-positioned afterwards.