Fig, 215.—Wallace-Lindesmith Hoist Bucket in Discharging Position.
Fig. 216.—Lumber Carriage for Wallace-Lindesmith Hoist.
Fig. 217.—Mixer Plant with Gravity Feed from Material Bins to Hoisting Bucket.
A popular construction for automatic bucket hoists is that shown by Figs. 217 and 218 by Mr. E. L. Ransome. The bucket is held upright by guides at its front and rear edges; to dump it a section of the front guide is removed at the desired dumping point which allows the bucket to overturn as shown. A friction crab hoist operated from the mixer engine runs the bucket. The mixer is located as shown. Figure 218 shows the foot of the hoist set in a pit with the mixer at surface level, but the hoist can be set on the surface and the mixer mounted on a platform. In the latter case a charging bucket, traveling from stock pile up an inclined track to the mixer platform, is generally used. A hoist like that illustrated, equipped with a ½-cu. yd. Ransome mixer, will cost about $1,500 and will deliver 15 cu. yds. of concrete per hour. Mr. F. W. Daggett gives the following figures of the cost of operation:
| Mixing Gang: | |
| Total 1 hr. | |
| 1 mixer foreman, also engineer, 25c. | $.25 |
| 1 man charging mixer, 20c. | .20 |
| 1 man running hoist, 20c. | .20 |
| 2 men wheeling sand, 17½c. | .35 |
| 4 men wheeling and shoveling stone, 17½c. | .70 |
| 1 man helping up runway, 17½c. | .17½ |
| 2 men carrying cement, 17½c. | .35 |
| Gang Placing Cement: | |
| 1 foreman, 25c. | .25 |
| 9 men wheeling concrete, 17½c. | 1.57½ |
| 3 men tamping concrete, 17½c. | .52½ |
| 1 man filling carts, 17½c. | .17½ |
| ——— | |
| Total labor cost per hour | $4.75 |
| Fuel, etc. | .50 |
| ——— | |
| 5.25 | |
This gives a cost of 35 cts. per cu. yd. for mixing and placing concrete.
In this particular case the mixer was charged by wheelbarrows. Frequently the stone and sand bins can be arranged to chute the materials directly into the charging hopper as shown by Fig. 217. In place of barrows two-wheeled carts of the type shown by Fig. 12 can be used. Mention has already been made of operating the charging bucket on an incline from stock pile to mixer. Such arrangements are described in Chapter IV.