A spindle driving device for a covering machine includes a plurality of groups of spindles. Each group of spindles includes a predetermined number of spindles and an electric motor is associated with each group. A driving pulley is removably installed on each motor and a tension pulley is associated with each group of spindles. An endless belt is stretched around the driving pulley, the spindle wharves attached to each spindle and the tension pulley in each group. The tension pulley is mounted at a central portion of an arm and the arm is supported at one end by a pivot which is connected to a slider for movement along a guide-rod for removing slackness in the endless belt. The other end of the arm is attached to an energizing member for biasing the arm in a direction for removing slackness in the endless belt.
