Improved Retractable Bollard

Abstract

This invention relates to a retractable bollard including an embedded outer housing having an open end and a closed end; a ram slideably mounted within the outer housing; and means for injecting fluid into, and means for removing fluid from, a chamber within the retractable bollard to move the ram relative to the outer housing between a retracted position and an extended position. The chamber is bounded by one or more sliding surfaces and one or more seals configured to move in sealing relationship relative to the sliding surfaces and the ram is able to be completely removed from the outer housing without separating the seals from the sliding surfaces.

1 . A retractable bollard comprising:
 an embedded outer housing having an open end and a closed end;   a ram slideably mounted within the outer housing, the ram having an outer surface; and   a mechanism for injecting fluid into, and a mechanism for removing fluid from, a chamber within the retractable bollard to move the ram relative to the outer housing between a retracted position and an extended position, the outer surface of the ram being exposed to the surroundings of the bollard when the ram is in the extended position;   wherein:   the chamber is bounded by at least one surface of the ram, one or more sliding surfaces and one or more seals configured to move in sealing relationship relative to the sliding surfaces; and   the ram is able to be completely removed from the outer housing without separating the seals from the sliding surfaces.   
     
     
         2 . A retractable bollard as claimed in  claim 1 , wherein the ram is able to be completely removed from the outer housing without exposing the sliding surfaces. 
     
     
         3 . A retractable bollard as claimed in  claim 1 , wherein the retractable bollard comprises shielding configured to shield at least one of the sliding surfaces and/or the seals when the ram is completely removed from the outer housing. 
     
     
         4 . A retractable bollard as claimed in  claim 3 , wherein the shielding shields at least one of the sliding surfaces of the chamber and the seals from contaminants. 
     
     
         5 . A retractable bollard as claimed in  claim 1 , wherein the ram comprises a cavity comprising an open end and a closed end, the open end of the cavity facing the closed end of the outer housing, and the retractable bollard apparatus further comprises an elongate member extending from the closed end of the outer housing into the cavity of the ram, the elongate member comprising:
 a rigid elongate body;   a head mounted on the elongate body and adapted to form the sealed chamber within the cavity of the ram; and   a fluid conduit configured to allow fluid to be injected into or removed from the chamber.   
     
     
         6 . A retractable bollard as claimed in  claim 5 , wherein the fluid conduit comprises a hollow cavity extending through the length of the elongate member. 
     
     
         7 . A retractable bollard as claimed in  claim 5 , wherein the fluid conduit fluidly connects the chamber with an opening in the outer housing. 
     
     
         8 . A retractable bollard as claimed in  claim 7 , wherein a bottom end of the elongate member is adapted to be received and retained in position during use by the opening in the outer housing. 
     
     
         9 . A retractable bollard as claimed in  claim 8 , wherein the outer housing comprises a socket defining the opening and configured to accommodate the bottom end of the elongate member. 
     
     
         10 . A retractable bollard as claimed in  claim 5 , wherein the elongate member is able to be completely removed from the outer housing together with the ram from the open end of the outer housing. 
     
     
         11 . A retractable bollard as claimed in  claim 5 , wherein the elongate member is able to remain within the ram if the ram is completely removed from the open end of the outer housing. 
     
     
         12 . A retractable bollard as claimed in  claim 5 , wherein the shielding comprises one or more shield members positioned between the elongate member and an inner surface of the cavity of the ram. 
     
     
         13 . A retractable bollard as claimed in  claim 12 , wherein the shield members are attached to the inner surface of the ram and configured to slide along the elongate body. 
     
     
         14 . A retractable bollard as claimed in  claim 5 , wherein the shielding comprises a conduit shield member positioned in or at the end of the fluid conduit and adapted to allow fluid to pass therethrough but prevent passage of contaminants. 
     
     
         15 . A retractable bollard as claimed in  claim 14 , wherein the conduit shield member is an air filter. 
     
     
         16 . A retractable bollard as claimed in  claim 1 , wherein the ram and the outer housing each comprise electrical connectors positioned on the ram and outer housing such that, when the ram is in one of the fully retracted and the fully extended position, the electrical connectors on the ram and outer housing are electrically connected such that, if a voltage is applied to the ram, a detectable change in the electrical characteristics of the ram occurs to indicate that the ram is in said one of the fully retracted and the fully extended position. 
     
     
         17 . A retractable bollard as claimed in  claim 1 , wherein the ram comprises electronic circuitry able to be powered by a voltage applied to the ram. 
     
     
         18 . A retractable bollard as claimed in  claim 3 , wherein at least a part of the shielding is electrically conductive. 
     
     
         19 - 33 . (canceled) 
     
     
         34 . A retractable bollard comprising:
 an embedded outer housing having an open end and a closed end;   a ram slideably mounted within the outer housing, the ram having an outer surface;   a mechanism for injecting fluid into, and a mechanism for removing fluid from, a sealed chamber, bounded by at least one surface of the ram, within the retractable bollard to move the ram relative to the outer housing between a retracted position and an extended position, the outer surface of the ram being exposed to the surroundings of the bollard when the ram is in the extended position;   wherein:   the ram is able to be removed from the outer housing while maintaining a volume within the chamber which is less than or equal to the volume of the chamber when the retractable bollard apparatus is in a fully extended configuration   
     
     
         35 . A retractable bollard comprising:
 an embedded outer housing having an open end and a closed end;   a ram slideably mounted within the outer housing, the ram having a cavity comprising an open end and a closed end, the open end of the cavity facing the closed end of the outer housing;   an elongate member extending from the closed end of the outer housing into the cavity of the ram, the elongate member comprising:   a rigid elongate body;   a head adapted to form a sealed chamber within the cavity of the ram, the sealed chamber bounded by at least one surface of the ram; and   a fluid conduit configured to allow fluid to be injected into or removed from the chamber to adjust the axial position of the ram relative to the outer housing.