Today in 1959, US Patent 2891555 A was issued, an invention of Albert E. Brookes, for his “Machine For Plucking Hops or Like Plants.” There’s no Abstract, although in the description it includes this summary:

This invention relates to a machine intended primarily for plucking hop flowers from their bines, but also usable for analogous purposes such, for example, as the plucking of beans form their bines or the separation of seeds from herbs and the like, and has for its object to provide such a machine in a convenient and efficient form, and particularly to provide an improved means for gripping and traversing the bines relative to plucking means.

In a machine according to the invention a plurality of pairs of endless driving chains are arranged parallel with one another, each pair of chains having parallel runs between which the bine is adapted to be held transversely for movement relative to plucking means.