Dynamit Nobel Aktiengesellschaft

Klaus Steffens

Gerhard Rehfeld

An apparatus adapted to be mounted on a surface grinding machine is provided for testing abrasive grains in single-grit scratch tests. To permit specimen preparation and scratching to be carried out on a single machine without changeover and without reclamping the specimen, and to maintain the infeed in the scratching operation constant by giving the specimen a contour corresponding to the cross-feed error, a belt grinder and a scratching device comprising a support disk, mounted by means of a main flange and a counterflange, and a scratching disk mounted on the main flange and carrying a single grain secured to its periphery along with a force-measuring system disposed thereunder, are designed as a structural unit adapted to be mounted on the spindle of the surface grinding machine, with a belt tensioning arm mounted to the headstock. The requisite natural frequency of the force-measuring system is obtained by locating a grain holder, a piezoelectric quartz crystal and a necked-down titanium bolt with rapid-acting tightening means on the rotating scratching disk beneath the abrasive grain.

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Aachen, Germany

Klaus Steffens