94 
CONCRETE SILOS 
Holes are bored in the segments at frequent intervals to permit the insertion 
of the curved end of a ^/g-inch iron rod shaped something like a stove 
poker, by means of which a segment is raised from one circle to the new 
course. A segment will weigh in the neighborhood of 125 pounds, and 
two men have no difficulty in handling it. 
Each Monsco mold equipment includes 90 clamps for holding the 
segments together and 16 irons for concrete roof and cornice. A clamp is 
easily attached and detached and holds the segments and circles together 
as if in a vise. 
The Monsco steel roof-molds are made of galvanized steel and are 
adjustable for 12-foot, 14-foot, 16-foot and 18-foot silos. The dormer 
window, which is one of the features of this construction, comes in two 
sections and can be used for any sized roof. 
For a number of years John H. McCoy has been successfully us- 
ing a system of forms of his own invention in the construction of large 
^ silos and railroad water tanks in many parts of the country. 
Forms This system is now owned and used by the Steel Concrete Con- 
struction Co. of Harris ville. Pa. The forms are of steel made in 
sections, each of which is supplied with a separate rig for hoisting. The 
materials are raised in steel buckets by horse power and deposited on a 
trough which travels around a circular track. This track makes it pos- 
sible to move the trough to any part of the work that it is desired to fill. 
The Peerless forms, manufactured by the New Enterprise Concrete 
Machinery Co. of Chicago, and used by the above company and a 
The Peerless ^^^S© number of silo contractors, are built of heavy galvanized 
Forms sheet iron with angle iron stiffeners. Both inner and outer 
forms are built in sections which are coupled together with small 
steel pins or spikes. They are held at the proper distance apart by a steel 
frame which also supports a derrick. The materials are raised in a steel 
bucket, horse power being used. 
The Polk system is operated by the Polk-Genung-Polk Co. of Fort 
Branch, Indiana, and a number of licensed contractors. The inner and 
The Polk outer forms are of heavy galvanized sheet iron, stiffened with 
System angle iron. They are suspended by rods and chains from an 
iron collar which slides on a hollow steel mast. The inner and 
outer forms are kept perpendicular and also held at proper distances 
apart by radial horizontal angle irons. These also serve to hold a plat- 
form. 
One of the chief advantages of the Polk System is the method of ele- 
vating the concrete and depositing it within the forms. The apparatus 
consists of a steel bucket and cable, the latter running over a pulley at- 
tached to a trolley which travels on a steel boom. This boom is attached to 
the central mast by means of a collar which allows it to swing around in a 
full circle. After it is filled with concrete the bucket travels upwards until 
it reaches the trolley on the boom. The trolley is then released automat- 
ically and the bucket travels until directly over the forms. The trolley is 
prevented from going further by a stop consisting of a steel pin placed 
through a hole in the boom. Power for elevating the materials is generally 
supplied by a horse. The forms are raised in the following manner: 
