Agronomy: Rube Goldberg on the Farm

The mechanization of U.S. agriculture has sent an incredible parade of improbable machines clanking across the nation’s farm land. But the combines and cotton pickers that led the assault on traditional farming methods already seem outdated compared to the latest contraptions. On the campus of the University of California’s College of Agricultural Engineering at Davis, the wildly inventive center of the farm-machinery revolution, a group of scientists and engineers are turning out automated Rube Goldberg devices faster than farmers can learn how to use them. Among the latest:

> THE PHRENOLOGICAL LETTUCE PICKER, which “feels” each lettuce head to determine if it is ripe for harvest. Towed over the lettuce bed at one mile per hour, a 6-in. by 18-in. conveyor belt creeps over each head, pushing it downward in passing. The machine’s small, electronic memory box has already been told how stiffly a ripe head should resist deflection. If the black box decides the head feels ripe, it triggers a clutch, which in turn sends a miniature guillotine slashing through the lettuce stalk. In recent tests, the machine lopped off some 4,500 heads an hour —five times more than the nimblest human headsman. Davis engineers are already at work building a pickup machine to follow the cutter.

> THE “NEEDLE -IN -THE -HAYSTACK” FINDER was devised to eliminate dangerous bits of baling wire in cattle feed. Davis engineers wrap a coil of copper wire around a standard pneumatic conveyor pipe that carries feed from chopper to storage bin. The wire is energized to set up a magnetic field inside the pipe. When a piece of iron or steel disturbs the field, an electrical pulse triggers a device that closes off the pipe’s supply of feed and opens a side slot. Out flies the baling wire, along with a small amount of hay.

> THE INTERNAL COMBUSTION NUTCRACKER gave Davis men quite a bang though it never went into full production. Walnuts were fed one by one into small cups mounted on a revolving drum. The drum turned the nuts against a saw, which nicked a hole in the shell. A tiny squirt of acetylene and oxygen was then shot into the hole. The nut, leaking gas, was dropped through a ring of flaming gas jets. The gas inside the nut exploded, blowing away the shell. “It was a humdinger,” says Davis’ Dean Roy Bainer. “Shelled 900 nuts an hour, and the meat just as clean as a whistle.”