A thermal conducting path between a relatively movable heat source (24, 20, 14) and a relatively fixed heat sink element (6, 15), is defined as a relatively narrow non-contacting conducting gap (10) between opposing conducting surfaces (12,8). In an embodiment where the heat source (24,20,14) is gimbal mounted, for movement with respect to two orthogonal axes (P, Y), its conductive surface (12) has a convex partial spherical shape while the relatively fixed surface (8) of the heat sink element (6, 15) has a concave partial spherical shape. In order to maintain a constant gap (10), the opposing surfaces have a common spherical centre located at the crossover (30) of said orthogonal axes (P, Y) and the spherical radii dimensions (R 1 , R 2 ) differ by the distance of said relatively narrow non-contacting gap (10) there-between.