The capacity of the mixer and hoisting bucket per batch, was 20 cubic feet. A 9 by 9-inch, 20-horse-power vertical engine was used to mix and hoist the concrete, steel, structural steel for columns, and lumber for the forms. A 30-horse-power boiler was used to supply the steam, which was located several feet from the engine, and is not shown in the plan view of the plant. A Ransome friction crab hoist was used to hoist the concrete, and was connected to the engine by a sprocket-wheel and chain. The steel and lumber were hoisted by means of a rope, wrapped three or four times around a winch-head which was on the same shaft as the mixer. The rope extended vertically up from the pulley, through a small hole in the floors, to a small pulley at the height required to hoist the lumber or steel; and then it extended horizontally to another pulley at the place where the material was to be hoisted. The rope descends over the pulley to the ground. A man was stationed at the engine to operate the rope. There were two rope-haulages operated from the pulley on the engine shaft, one being used at a time. On being given the signal, the operator wrapped the rope around the winch-head three or four times, kept it in place, and took care of the rope that ran off the pulley as material was being hoisted.
Wheelbarrows were used in charging the mixer, and hand-carts were used in distributing the concrete. The runways were made by securely fastening two 2 by 10-inch planks together in sections of 12 feet to 16 feet, which were handled by two men. By keeping the runway in good condition, two men were generally able to distribute the concrete, except on the lower floors, and when it was to be trans ported the full length of the building. The capacity of the carts was 6 cubic feet each. Concrete for the ninth floor was hoisted and placed at the rate of 15 cubic yards per hour.
347. Plant for the Locust Realty Company Building. The plant used for constructing a five-story reinforced-concrete building, 117 feet by 200 feet, for the Locust Realty Company, by Moore Com pany, Inc., is a good example of a centrally located plant. Near the center of the building is an elevator shaft, in which was constructed the framework for hoisting the concrete. Fig. 147 shows the arrange ment of the plant, which is located in the basement and near the center of the building. The mixer is located so that the concrete can be dumped directly into the hoisting bucket. The chute for re ceiving the materials being about 18 inches above the basement floor, it was therefore necessary to wheel the materials up an incline. An excavation was made below the level of the basement floor for the hoisting bucket. The mixing was done by a steam engine located on the same frame as the mixer. The concrete was hoisted by a hoisting engine which was located about twenty feet from the shaft. A
small hoisting engine was also used for hoisting the steel and lumber used for forms; as this engine was located some distance from the rest of the plant, it is not shown in Fig. 147. The three engines are supplied with steam from a portable boiler which is located as shown in the figure. The efficiency of this plant was shown in the mixing and hoisting of the con crete for the second floor, when 240 cubic yards were mixed and hoisted in 16 hours, or at an aver age rate of one cubic yard in four All materials were delivered at the front of the building; and therefore it was necessary to transport the cement, sand, and stone about 100 feet to the mixer. This was done by means of wheel barrows especially designed and made for Moore & Company, Inc , the capacity being four cubic feet. The concrete was a 1: 2: 4 mix, and was mixed in batches of 14 cubic feet. The materials for a batch, therefore, consisted of 2 bags of cement, 1 wheelbarrow of sand, and 2 wheelbarrows of stone.
The lumber for the forms was 11-inch plank, except the support and braces. Details of the forms will be given and discussed under the heading of "Forms." 34S. Concrete Plant for Street Work. A self-propelling mixing and spreading machine has been found very desirable for laying con crete base for street pavements. Fig. 14S illustrates a plant of this kind, which has been devised by the Municipal Engineering & Con tracting Company. One of these machines was very successfully used in Buffalo, N. Y., in 1907.
The mixer is of the improved cube type, mounted on a heavy truck frame. The con crete is discharged into a specially designed bucket, which receives the whole batch and travels to the rear on a truck which is about 25 feet long. The head of the truck is supported by guys, and also by a pair of small wheels near the middle of the truck, which rest on the graded surface of the street. The truck or boom is pivoted at the end con nected to the main truck, and has a horizontal swing of about 170 de grees, so that a street 1:0 feet wide is covered. An inclined track is also con structed, on which a bucket is operated for elevating and charging the mixer. The bucket is loaded while resting on the ground, with the proper ingredients for a batch, from the materials that have been distribu ted in piles along the street. The bucket is then pulled up the in cline, and the contents dumped into the mixer. An automatic water measuring supply tank mounted on the upper part of the frame insures a uniform amount of water for each batch mixed. The power for hoisting, mixing, and distributing the concrete, and propelling the machine, was furnished by a 16-horse-power gasoline engine of the automobile type. The machine can be moved backward as well as forward, and is supplied with complete steering gear.