The invention relates to a device for converting a rotational movement into a translational movement, said device comprising: a first element (303) that is rotated around a stationary center of rotation (401) by a rotation means (301); a second element (307) that is translated along a translation axis (311) by rotating the first element (303); a cam (305) that is rigidly connected to the first element (303), said cam (305) having a cam channel (306) in which a roller (308) moves, wherein said roller is rigidly connected to the second element (307). Said device is characterized in that the cam channel (306) has an inner surface (402) for contact with the roller (308), said roller (308) being in contact (500) with the inner contact surface (402) when the first element (303) is rotated in a first rotational direction (404), said inner contact surface (402) defining a curve of the type developing from a circle.