Patent ID: 6848856
Filing Date: 2005-02-01
Classification: E01F

Abstract:
1. A barrier arrangement for the control of traffic including at least one pylon assembly comprising: an elongate post mounted in a generally vertical manner within the ground and telescopingly movable relative thereto between an uppermost position wherein said post extends above the ground surface and a lowermost position wherein said post is disposed substantially completely beneath the ground; and a remotely-actuable drive mechanism for moving said post between said uppermost and lowermost positions, said drive mechanism including an elongate and generally vertically oriented rotatable drive shaft, and a drive member coupled to said drive shaft and fixed to said post, wherein rotation of said drive shaft causes displacement of said drive member and said post relative to and along said drive shaft to move said post into one of said uppermost and lowermost positions, wherein an abrupt and downwardly directed axial force applied to an upper end of said post during upward movement thereof decouples said drive member from said drive shaft.