86 Concrete Silos 



moved up 'as the work progresses and to which the radial 

 staging arms are attached. There are two sets of these 

 arms. The upper platform is flush with the top of the 

 silo, from which the forms are manipulated arid the pour- 

 ing is done. Each of these arms consists of two angle 

 irons telescoped on each other and with bolt holes at 

 suitable intervals, so th'at they can be adjusted to the 

 various diameters it is desired to build. At one end they 

 rest in slots in the collars on the mast, and at the other 

 end they rest on the circles of angle iron which are car- 

 ried right up with the forms to give them their true 

 shape. These circles are made in segments for easier 

 handling, but can be rigidly clamped together for use. 



The upper ring, which holds the forms in shape, also 

 c'arries a single track on which run the two wheels of a 

 small car. This car rests on a frame attached to a loose 

 collar around the mast and just above the collar which 

 carries the upper platform. It thus can be pushed 

 around to any p'art of the circle desired, swinging 

 around the mast as a pivot and the outer end carried by 

 the wheels on the track. This car is merely a frame 

 with bearings on which the bucket of concrete can be set 

 when it is brought up from below, the arrangement being 

 such that it can be tilted to dump into the forms, a steel 

 apron being attached to the 'car to direct the flow into 

 the forms and prevent loss of concrete. 



A derrick, also attached to the mast in the center, 

 by which all materials are handled, completes the 

 outfit. 



The ordinary wall thickness in this system is 6 

 inches, though the adjustability is such that almost any 

 desired thickness can be obtained, the only additional 

 parts of the outfit needed being spacers for the desired 

 thickness and perhaps additional fractional plates in 



