In a configuration in which a carriage jumps at an end of a screw without using a sensor for detecting a position, when a load for moving the carriage in a longitudinal direction is increased, the carriage jumps at an unintended position of a charging wire. A carrier of gearset and the input shaft couple forming shaft. In response to receiving the whiteboard content data from the smart whiteboard device, the mobile device may transfer the received whiteboard content data to the other smart whiteboard device. In the special situation mode, the limit value is equal to a second limit value, which is higher than the first limit value. RAZs are displayed as \u201cgo, no-go\u201d signals on the computer monitor.