Threshing machine

A threshing machine or a thresher is a piece of farm equipment that separates grain seed from the stalks and husks.

During the 19th century, threshers and mechanical reapers and reaper-binders gradually became widespread and made grain production much less laborious.

They had faced unemployment for years, due to the widespread introduction of the threshing machine and the policy of enclosing fields.

With fewer jobs, lower wages and no prospects, the threshing machine was the final straw; it would place them on the brink of starvation.

In 1834, John Avery and Hiram Abial Pitts devised significant improvements to a machine that automatically threshes and separates grain from the chaff, freeing farmers from a slow and laborious process.

Below the straw walkers, a fan blows a stream of air across the grain, removing dust and small bits of crushed plant material out of the back of the combine.

The grain, either coming through the concave or the walkers, meets a set of sieves mounted on an assembly called a shoe, which is shaken mechanically.

The incompletely threshed grain is returned to the cylinder by means of a system of conveyors, where the process repeats.

A large amount of chaff and straw would accumulate around a threshing machine, and several innovations, such as the air chaffer, were developed to deal with this.

The corn sheller was almost identical in design, with slight modifications to deal with the larger kernel size and presence of cobs.

The concave clearance, cylinder speed, fan velocity, sieve sizes, and feeding rate must be adjusted for crop conditions.

Even after the combine was invented and became popular, a new compact-size thresher called a harvester, with wheels, still remains in use and at present it is available from a Japanese agricultural manufacturer.

In his film score for Of Mice and Men (1939) and consequently in his collection Music for the Movies (1942), American composer Aaron Copland titled a section of the score "Threshing Machines," to suit a scene in the Lewis Milestone film where Curley is threatening Slim over giving May a puppy, when many of the itinerant worker men are standing around or working on threshers.