Concrete Silos 



75 



lifting of which allows the inner sections to swing free. 



To keep the vertical reinforcing in its proper posi- 

 tion in the center of 

 the wall, small steel 

 clips are provided. 

 The vertical reinforc- 

 ing passes through 



these clips, which fit I k 



over the stems of the 

 steel tees. 



For placing tine 

 concrete between the 

 forms, a V-shaped 

 dumping bucket is 

 provided. This buck- 

 et is supported by a 

 crane pivotally at- 

 tached to the cen- 

 ter mast directly 

 above the top collar 

 of the hub, and can be easily swung to any part of the 

 wall space. It is hoisted by means of a rope and series 

 of pulleys so arranged that the hoisting force is applied 

 horizontally from without the structure. A small open- 

 ing, through which the hoisting rope works, is cut in 

 the wall near the bottom of the first fill of concrete. 

 When the bucket is hoisted it is coupled to a carrier on 

 the crane by means of a hinged hook and is then swung 

 to any part of the wall space desired. 



The scaffolding, both inner and outer, is swung from 

 the steel tees, which project some distance beyond the 

 wall. 



The operation of the machine is very simple. The 

 forms are set, the reinforcing bars are placed in posi- 



Polk System Machine in Operation 



