AUTOMATISK TRANSMISJON

An automatic transmission (15) is disclosed which only shifts dependent on the torque in the input shaft (10) and the output shaft (11), said shafts always being interconnected via drive wheel means (1, 2, 3, 4). The input shaft (10) includes a portion with external threads (9) on which a first driving wheel means (1) having complementary internal threads is mounted in such a way that first driving wheel means is slightly axially moveable relative to input shaft (10). A second driving wheel means (2) is axially moveable and freely rotatable on input shaft (10) for releasably engaging as a coupling means (17) a ring wheel (8) which is fixed to the input shaft. A third free wheeled driving wheel means (3) is supported on output shaft (11), said third driving wheel means being constantly in mesh with first driving wheel means (1). A fourth driving wheel means (4) is fixed to the output shaft (11) and is constantly in mesh with the second driving wheel means (2). Means like a spring (7) presses the first driving wheel means (1) axially towards and into engagement with the second driving wheel means (2).