Stone Crushing Machines

How did the Hopewell Quarry and other late 1800s / early 1900s operations turn walls of rock into crushed stone?

The first step is clear: drill holes into the rock wall, stuff in dynamite, and then blow off the front layer of the wall. But now you have a mess of boulders and big chunks of rock and rubble. So what’s next?

You could deploy lots of people with hammers and chisels, but this was the culmination of the age of steam, so a better answer would be to invent some kind of stone breaker / rock crusher machine – like the Blake jaw crusher.

Example rock face at Pennington Quarry [Wildgrube]
Blake Stone Breaker – 2011 Demo

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The Blake Jaw Crusher

Eli Whitney Blake

Various designs for stone crusher equipment were patented in the 1830s and 1840s, but the first successful mechanical rock breaker, the Blake jaw crusher, was patented in 1858 by Eli Whitney Blake (nephew of Eli Whitney, the inventor of the cotton gin).

Blake was supervising the macadamizing of city streets with crushed stone, and saw the need for machinery for breaking stone. His invention was simple and effective, and lead to his entry into the National Inventors Hall of Fame.

This video clip shows a working Blake Jaw Crusher machine being demonstrated in 2011. It is labelled Blake “Stone Breaker, W H Baxter, Leeds England,” and was manufactured around the 1890s.

2011 demo of Blake Stone Breaker

This is the kind of equipment likely to have been used by quarries in the Hopewell Valley around the turn of the century, including the Hopewell Quarry (later Swim Club) just west of Hopewell Borough, and other quarries around the Hopewell Township.

Jaw Crusher Operation

Blake Stone Breaker – Hopper

The Blake Jaw Crusher consists of a pair of upright metal plates (the jaws) in a rock hopper. The plates make a V shape, with one fixed (one side of the hopper), and the other pivoting to continually open wider and then close against the fixed side (the single toggle design).

When a rock is dropped in the hopper between the jaws it falls until stopped by its size, is crushed into smaller pieces by the cycle of the jaws, and then the resulting pieces fall further and the cycle is repeated until the pieces are small enough to fall out the bottom between the two jaws.

Blake Stone Breaker – 2011 Demo

The engine uses a toggle linkage that converts the rotation of a flywheel into the back-and-forth motion of the movable jaw using an eccentric shaft that moves in an elliptical orbit.

Rock crushing machines with this basic design are still available today, and come in different sizes depending on the size of rocks to be crushed and the volume of work to be done.

In 1898, Joshua S. Cope’s stone quarry (our Hopewell Quarry) had two crushers installed, side by side, that processed 225 tons of rock a day (roughly equivalent to 2-3 current railroad boxcars).

The Blake Patent

E. W. Blake, Machine for Crushing Stone, U.S. Patent 20542, 6/15/1858

1858 Patent – E W Blake – Crushing Stone – US20542

My stone breaker, so far as respects its principle, or its essential characteristics, consists of a pair of jaws, one fixed and the other movable, between which the stones are to be broken, having their acting faces nearly in an upright position, and convergent downward one toward the other in such manner that while the space between them at the top is such as to receive the stones that are to be broken, that at the bottom is only sufficient to allow the fragments to pass when broken to the required size; and giving to the movable jaw a short and powerful vibration through a small space, say one fourth of an inch, more or less. By means of this form and arrangement of the jaws, and this motion of the movable jaw, when a stone is dropped into the space between them, it falls down until its further descent is arrested between their convergent faces; the movable jaw, advancing, crushes it, then receding, liberates the fragments and they again descend, and if too large, are again crushed, and so on until all the fragments, having been sufficiently reduced, have passed out through the narrower space at the bottom.

We welcome additional information and materials to share on the local quarrying operations.

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