Abstract: A transducer head for a moving surface dynamometer comprises a casing having connections for attachment to a extremity of a support arm on a sliding carriage of a loading head of the eventual dynamometer. An axle housing in the casing supports an axle of a test subject to be spun in rolling contact with the moving surface. A multiplicity of strain transducer links are connected in load-transmitting relationship between the axle housing and the casing for supplying signals indicating tensile or compressive load therein. There are six such links in a defined pattern. Each link is advantageously threadedly attached to the axle housing and has at its outer end a male tapered threaded region that registers with a straight threaded bore in a cap attached to the casing, a tapered sleeve having external and internal threads of the same pitch being tightenable to connect the outer end of the link to the cap and thence to the housing without correspondingly straining the link.

Abstract: A drum shaft assembly for a drum dynamometer includes at least one annular inertia element on the shaft and releaseably couplable to the shaft and drum to vary the inertia thereof. The assembly carries first interrupted thread means releasably engageable with second interrupted thread means rotatably supported in the inertia element. A manipulator is slideable axially of the drum and shaft assembly between a stand-by position and a working position where it can offer or receive the inertia element to or from the shaft and drum. The manipulator has a support for supporting the inertia element and a rotatable key operable to bring about relative rotation of the first and second interrupted thread means to fasten the inertia element to or to release the inertia element from the shaft and drum.