The invention is a device (1, 100, 200, 300, 400, 500, 600, 700) for converting a rotary motion into a linear motion, comprising a first threaded element (3) that defines a first axis (7), suited to be coupled with a second threaded element (4) defining a second axis (10), said axes (7, 10) being substantially parallel to each other but not coinciding with each other. The device (1) also comprises means (12) arranged between the first threaded element (3) and the second threaded element (4), suited to transmit the rotary motion imparted to one of the elements (3, 4) to the other.