Telescoping bollard with screw drive

A bollard assembly having a rotational axis along a length thereof, said bollard assembly comprising:

• an elongated housing and an inner wall defined by said housing;
• a bollard spaced radially inward of said housing and axially displaceable therein;
• a threaded drive shaft receiver centrally fixed within said housing for threaded reception of a threaded drive shaft;
• and
• a threaded drive shaft suspended within said housing and threadedly received by said receiver, said drive shaft operably connected to said bollard, whereby rotation of said drive shaft establishes vertical displacement of said drive shaft and said bollard;
• a longitudinal ridge extending along said inner wall parallel to said axis of said bollard assembly and substantially coextensive with said housing, said ridge defining a key having an arcuate length and a radial length;
• at least one guide ring circumferentially fixed about said bollard, said guide ring having a radial length at least substantially equivalent to the radial length of said key;
• a notch defined in said guide ring, said notch defined by an absence of the guide ring about said bollard and said notch having an arcuate length at least substantially equivalent to said key;
• a bearing assembly substantially circumferentially disposed about said bollard at said second end of said housing and constrained by said guide ring, said bearing assembly slidably engaged with said inner wall upon vertical displacement of said bollard;
• and
• a gap defined across the length of said bearing assembly and parallel to said axis, said gap having an arcuate and radial length substantially equivalent to said key;
• wherein upon rotation of said drive shaft, the bollard is vertically displaced in unison with the vertical shaft but substantial rotational displacement of the bollard is prevented.