This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
Where the amount of slack paid out through the eye of the needle is greater than the amount of the dip of the needle-bar, an independent take-up is required. Its function is to pull up the loop after it has passed round the shuttle, or the hook has passed through the loop. D, in Fig. 212, is the take-up, and, en passant, it is to be noted that it should be always brought to its highest point before commencing to stitch, or before removing the work from the machine.