US Patent 7244075 Telescoping bollard with screw drive

The present invention includes a bollard assembly 1 containing an an elongated housing 4. A bollard 2 is spaced radially inward of the housing 4 and is axially displaceable therein. A threaded drive shaft receiver 32 is centrally fixed within the housing 4 for threaded reception of a threaded drive shaft 30. The threaded drive shaft 30 is thereby suspended within the housing 4 and threadedly received by the receiver 32. Upon activation of the drive shaft 30 operably connected to the bollard 2, rotation of the drive shaft 30 establishes simultaneous vertical displacement of the drive shaft 30 and the bollard 2.