Abstract: A method for inspecting contact between mating gears that includes applying a mixture to teeth of a first gear, teeth of a second gear, or the teeth of both the first and second gears. The mixture includes a lubricating oil and a fluorescing dye. The first gear is rotated to drive the second gear. While the second gear is being driven by the first gear, electromagnetic radiation, such as ultra-violet radiation, is applied to the teeth of at least one of the first and second gears to cause the teeth to fluoresce. The fluorescing teeth of the second gear are inspected to identify a tooth inspection zone that approximates a zone of contact between the teeth of the first and second gears.

Abstract: A method for inspecting contact between mating gears that includes applying a mixture to teeth of a first gear, teeth of a second gear, or the teeth of both the first and second gears. The mixture includes a lubricating oil and a fluorescing dye. The first gear is rotated to drive the second gear. While the second gear is being driven by the first gear, electromagnetic radiation, such as ultra-violet radiation, is applied to the teeth of at least one of the first and second gears to cause the teeth to fluoresce. The fluorescing teeth of the second gear are inspected to identify a tooth inspection zone that approximates a zone of contact between the teeth of the first and second gears.

Abstract: Helical or spur gear drive comprising a driven gear and driving gear wherein the driving gear has double crowned teeth defined as (i) an envelope to a family of surfaces generated by a skew or straight rack-cutter having a parabolic tooth profile in normal section and then (ii) as an envelope to a family of tool surfaces that are generated while the tool performs a plunging motion with respect to the driving gear in the direction of the shortest distance between the axes of rotation of the tool and the driving gear and tool plunging motion is varied by a parabolic function, whose variable is displacement of the tool in a direction parallel to the rotational axis of the driving gear. The driven gear has a tooth surface defined as the envelope to a family of surfaces generated by a rack-cutter which surface is parabolic cylinder or a plane.