aneroid barometer

A barometer with a partially evacuated bellows chamber connected to a pointer with a pen recording atmospheric pressure on a drum chart. The bellows responds to atmospheric pressure.

Abrasion

The surface loss of a material due to frictional forces; the wearing away of any part of a material by rubbing against another surface

Antioxidant

A substance used to retard deterioration caused by oxidation

Angular misalignment, double-engagement Shaft

The minor angle between the axial centerline of the structure joining the two flexing elements and either of the shaft centerlines. Thus, there are two misalignment angles associated with a double-engagement coupling. These two angles are not necessarily equal, since they are the result of common parallel offset combined with the angular misalignment of the respective shaft end.

Anti sludge gear coupling design

A gear coupling, design that minimizes sludge-gathering pockets in continuously lubricated couplings.

Assembly check balance

A procedure in which an assembly is placed on a balance machine and the potential unbalance is measured. This can be done to a component-balanced coupling or to an assembly-balanced coupling.

Axial natural frequency (A.N.F.)

A cyclic response frequency determined by the mass of the flexible center element acting against the axial spring rate of the flexible elements. The spring rate may vary with the deflection of the flexible element; therefore, a frequency band corresponding to deflection amplitudes from zero to the maximum allowable amplitude must be considered.

Axial reference point shaft

The axial position on the shaft of the driving or driven machine (normally the extreme end of the shaft) from which axial distances are measured.

Athermal Transformation

A reaction that proceeds without benefit of thermal fluctuations; that is, thermal activation is not required. In contrast, a reaction that occurs at constant temperature is an isothermal transformation ; thermal activation is necessary in this case and the reaction proceeds as a function of time.

Ausforming

Thermomechanical treatment of steel in the metastable austenitic condition below the recrystallization temperature followed by quenching to obtain martensite and/or bainite.