Abstract: An oscillator for reciprocating tools or other devices. Driving sprockets are mounted for rotation on a frame or in a housing and a pair of driven sprockets are mounted on the frame, each to be driven by a respective driving sprocket. The driven sprockets are outwardly of the driving sprockets, all sprockets having their axes in the same plane. Eccentrically mounted masses are on the shafts of the driven sprockets which when rotated generate forces on the axes of the driven sprockets. These forces are transmitted to the frame through shafts of the driven sprockets. A couple is generated about the axis of the driving sprocket causing the frame to oscillate. A tool attached to the lower end of the frame is thereby reciprocated.

Abstract: An improved testing device and method to measure the degree of polarization potential on the interface of a metal structure and its environment where said structure is protected against corrosion through a cathodic protection system.The testing device includes adjustable stop means associated with a conventional electrometer to reduce the excursion of the needle of said meter and thereby achieve a more accurate reading of the polarization potential of the metal structure.