THE POLK SYSTEM MACHINE 



wall forms HIV care- 

 fully rolled and 

 tested for exact cur- 

 vature. They are 

 rigidly bolted to the 

 radiating steel Tees. 

 The outer sections 

 are bolted together 

 at their ends thru 

 holes in the frames. 

 The inner sections 

 are similarly fas- 

 tened together, but 

 they carry a steel 

 wedge between them, 

 the lifting of which 

 allows them to swing 

 free. The fact that 

 both inner and outer 

 forms are securely 

 bolted to the rigid 

 steel Tees insures 

 perfect curvature 

 and alignment for 

 every portion of the 

 wall'. 



For placing the 

 concrete in between 

 the forms a V-shaped 

 dumping bucket is 

 used. This bucket is 

 supported by a crane 

 pivotally attached to 

 the centermast di- 

 rectly above the top 

 collar of the hub. It 

 can be easily swung 

 to any part of the 

 wall space. It is 



Polk System Silos Are Indestructible 



