Page:1902 Encyclopædia Britannica - Volume 25 - A-AUS.pdf/192

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AGRICULTURAL

MACHINERY

adjusting the angle which the teeth make with the ground, j smoothing harrow. The small figure illustrates a spring and thus convert the machine from a pulverizer to a I connexion between the adjusting lever and its locking

Pig. 4.—Harrow.

Showing tooth mechanism of harrow.

bar, which allows the teeth to yield upon striking an before described. The levers enable the operator to raise the teeth more or less, and thus free them from trash, obstruction. The course of improvement of the harrow has been and also regulate the depth of action. The next improvement of the harrow is illustrated in much the same as in the plough, i.e., in so constructing it that the operator may ride and control its movements Fig. 6. with ease from his seat on the machine.

Pig. 7.—Roller pulverizer. Pig. 5.—Spring-tooth harrow. Fig. 5 illustrates a spring-tooth harrow arranged for riding. In this harrow the independent frames are carried upon wheels, and a seat for the operator is mounted upon standards supported by the two frames. The teeth consist of flat steel springs of scroll form, which

This machine consists of a main frame, having a pole and whiffle-trees attached, and to this frame are pivoted, near their outer ends, two supplemental frames, each of which has mounted therein a shaft carrying a series of concavo-convex disks. The supplemental frames may be swung by the adjusting levers to any angle with relation to the line of draft, and the disks then act like that of the disk plough, throwing the soil outward with more or less force, according to the angle at which they are set, and thus thoroughly breaking up and pulverizing the clods. Above the disks is a bar to which are pivoted a series of scrapers, one for each disk, which are held to their work with a yielding action, being thrown out of operation when desired by the levers shown in connexion with the operating bar. The pans on the main frame are used to carry weights to hold the disks down to their work. For the purpose of more thoroughly pulverizing the soil, a roller is frequently used, and an improved form of this implement is shown in Fig. 7. It consists of a set of skeleton rollers carried on a shaft, and revolving freely in such a manner that the longitudinal bars break up all lumps as the roller passes over them. One of the hardest and most disagreeable tasks of the farmer is the hauling and Pig. 6.—Disk harrow. distribution of manure and fertilizers; and yield to rigid obstructions, and are mounted on rock for the purpose of lightening his labours in this respect a shafts in the same manner as in the walking harrow machine has been produced (see Fig. 8).