The apparatus mounts a locking element into a groove in an edge of a panel. An advance device feeds a stream of locking elements to a pressing device which mounts the locking elements into the groove on the edge of the panel. The locking elements are fed from a line of locking elements stored on a reel. A separating device cuts the line of locking elements into individual locking elements. The separating device is positioned either upstream of the advancing device or immediately upstream of the pressing device. When the separating device is immediately upstream of the pressing device, a spring is used to flex the stream during the short stoppage when the separating device separates individual locking elements from the line of locking elements.