Abstract: A dveljagimmal device (1) serving as a control mechanism and a gearing suitable for use in conjunction with a rotary machine of the "cat and mouse" type. The device (1) comprises a stationary housing (2) from which extends a first (3) and second (4) shaft, the shafts (3,4) being coaxial. The device (1) is characterized in that the second shaft (4) terminates in a frame (5) which rotates in company with rotation of the second shaft (4). The device (1) further comprises a first (6) and a second (7) annular bevel gear, which first (6) and second (7) annular bevel gears are fixedly mounted to the housing (2), are coaxially aligned with the first (3) and the second (4) shafts, and are spaced apart allowing the frame (5) to be freely rotatable therebetween.