Method and apparatus for pumping concrete to form structure at elevated heights

Apparatus for lifting flowable concrete mix to an elevated height for introduction into a form system defining an annular structure comprising:

• crane means including a non-rotatable ground supported, upright tower made up of a number of stackable units mounted one on top of the other;
• an elongated jib rotatably carried by the tower adjacent the upper extremity thereof and swingable about the vertical axis of the tower;
• an elongated boom;
• adjustable suspension means between the boom and the jib supporting the boom in underlying relationship to said jib and operable to permit selective adjustment of the vertical angularity of the boom with respect to the jib while allowing variation of the horizontal angularity of the boom with respect to the longitudinal axis of the jib as well;
• concrete pumping mechanism substantially at ground level;
• piping means joined to the pumping mechanism, supported by and extending upwardly along the tower depending upon the number of units making up the same to a level approaching that of the boom;
• conduit means on the boom, fully supported by the latter, extending along at least a part of the length thereof and having an inboard end adjacent the tower and an outboard end at the opposite extremity of the same;
• elongated flexible conduit structure coupled at opposite ends thereof to the inboard end of the conduit means and the upper end of the piping means respectively and constructed and arranged to allow vertical as well as some horizontal movement of the inboard end of the conduit means with respect to the piping means during rotational movement of the boom about the axis of the tower as the conduit structure flexes;
• and
• concrete placement means joined to the outboard end of the conduit means for facilitating selective introduction of concrete into said forms as the concrete is pumped thereto by said mechanism via the piping means, said flexible conduit structure, the conduit means and said concrete placement means,
• said jib being rotatable in either direction to an extent allowing movement of the boom through opposite arcs such that the concrete placement means may be maneuvered to permit introduction of concrete mix into the entire 360.degree. circumferential extent of the form system making up said annular structure,
• said flexible conduit structure being of a length and sufficiently flexible to allow the inboard end of the conduit means to be swung vertically as necessary to maintain a required vertical angularity of the boom and thereby the conduit means after the outboard end of the conduit means has been positioned at a desired variable level for placement of concrete in said form system through said placement means and to accommodate changes in the horizontal angularity of the boom and thereby the conduit means with respect to the longitudinal axis of the jib as the latter and thereby the boom are swung about the tower in opposite directions through arcs allowing the concrete placement means to be positioned in concrete mix directing relationship to the full circumferential extent of the annular forms.