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The earliest U. S. patent on a crushing machine was issued in 1830. It covered a device which, in a crude way, incorporated the drop hammer principle later used in the famous stamp mill, whose history is so intimately linked with that of the golden age of American mining. Ten years later another patent was issued, which comprised a wooden box, containing a cylindrical drum-apparently of wood also- on which a number of iron knobs, or hammers, were fastened; the expectation was that this drum, when revolved at about 350 r.p.m., would shatter the rock fed into the box. This device, although it was conceived as an  impact crusher and thus would rate as a forerunner of the hammermill, bore a somewhat closer resemblance to the single sledging-roll crusher. There is no evidence that either of these early inventors carried their work through to fruition.
Eli Whitney Blake invented the first successful mechanical rock breaker-the Blake jaw crusher patented in 1858. Blake adopted a mechanical principle familiar to all students of mechanics, the powerful toggle linkage. That his idea was good is attested to by the fact that the Blake type jaw crusher is today the standard by which all jaw crushers are judged, and the leading machine of the class for heavy-duty primary crushing service.
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