Abstract: An actuation device for a drive element, such as the drive gear of a gripper needle encompasses a box which can be attached to the sley of a shuttlesess loom. Accommodated in this box is a traction means-transmission or drive containing a toothed belt of a drive pulley or disc which is operationally connected with the drive gear and a tensioning pulley or disc. The run of the toothed belt extends essentially parallel to a slide guide for a slide which is fixedly connected with the aforementioned belt run. The slide or carriage is moved to-and-fro by means of a lengthwise adjustable intermediate rod through the action of a crank drive. The adjustable spacing between the reversal points of the slide constitutes a measure for the insertion depth of the weft thread carrier into the shed. This enables a simple and robust as well as adaptable conception by means of which there can be obtained an extremely precise and unchanging insertion depth of the weft thread carrier into the weaving shed.