PRACTICAL SILO CONSTRUCTION 37 



ous air-chamber between the walls, a feature that is 

 an absolute preventative against freezing of the 

 silage. 



These wall-clamps are constructed of strap iron, 

 and may be built by any one at a slight cost. The 

 steel sheets are bolted or riveted to the clamps as 

 shown in Fig. 6, and each section is then bolted to- 

 gether or fastened with a small clamp, if the sec- 

 tions are to be raised separately. The core form 

 collapses when the center-bar with handle is raised. 

 This same operation causes the outside forms to 

 draw away from the concrete wall, thus freeing the 

 form from the concrete at all points. 



When the form is again lowered into position the 

 core is pressed outward to its proper place, and the 

 outside forms drawn in to the correct circumference. 

 The simple act of lowering the form automatically 

 locks it into position for filling, while the small 

 metal bars at the bottom of the center-bar engage 

 with the concrete wall and prevent the centering 

 from slipping down. 



The sections are reinforced with bars of strap 

 iron riveted to the sides of the steel sheets, as shown 

 in illustration, thus holding them to the true circum- 

 ference of the circle. 



The easiest method of using this style of form is 

 not to have more than two or three clamps to each 

 section, thus making the sections quarters or eighths 

 of the circumference of the silo. These sections 

 are raised separately by removing the small clips or 



