Abstract: The action curve (A), that is, the locus of the gearing contact points throughout the gearing process, is a lemniscate (Lg, Ld) having a double point coinciding with the rolling point (T) of two pitch circles (Prg, Prd). The gearing contact begins at one of the apexes (Sgh) of the lemniscate under a zero Hertzian pressure between two profile points where the profiles have the same curvature centered at the rolling point (T). Wear and operating noise are reduced.

Abstract: The locus of a gearing contact points called an action curve (A) is embodied in the form of a lemniscate (Lg, Ld) having a double point coinciding with the rolling point (T) of two pitch circles (Prg, Prd). The gearing contact is carried out at the top point (Sgh) of the lemniscate under a zero wireless pressure between two points where profiles have the same centred curve on the rolling point (T). Said invention is used for reducing wear and operating noise.

Abstract: A closed system rotary machine has an inner shaped element (1) and an outer shaped element (2) which define therebetween cavities or capsules having a variable volume (V1, V9). The contact points which define the capsules (C1, C9) are disposed along lines of action (CA1, CA2, CA3) which are concurrent at junction points BN and BM, where the cavities begin and end respectively. The contacts (C2) at points located on the tangent (T) common to both pitch circles (6, 7) are osculating elements with a shared centre of curvature which is situated at the rolling point (R) of the pitch circles (6, 7). The invention can be used to ensure that the capsules form and disappear very gradually and to facilitate the distribution of the capsules when they are forming and disappearing in order to increase the leak paths.