Model of a horse gear and crushing roll

Model of a horse gear and crushing roll with roller and trough apparently designed for crushing material, from the Watt Collection.

This model is associated with the firm of Boulton and Watt, steam engine manufacturers in Birmingham, and may be connected with their work supplying engines to mines in Cornwall, where ore needed to be crushed after it had been extracted from the mine. The horse gear takes the form of a horizontal lever which a horse would have been harnessed to, turning on a vertical axis. A projecting stud on the upper side of the lever forms a crank-pin from which a connecting rod is carried to a swinging lever. From this lever two links proceed to the axle of a vertical edge runner, which can be rolled in the fixed trough, crushing material in the trough beneath it as it rotates. The trough has a grid bottom through which the crushed material escapes when sufficiently reduced.