Semi-automatic machines require an operator to hang the books in their centers over a metal "wing." The machine then automatically clamps the book, coats the board papers with adhesive, fits the case on the text block and completes the operation. Three-wing casing-in machines are capable of processing books up to 3 inches in thickness (including covers), and, lying open, 14 inches high and 22 inches wide, at speeds up to 25 books per minute.
A fully automatic machine does not require timed feeding or removal of books. It can process books measuring not less than 3 3/8 inches in height, 2 1/2 to 7 1/2 inches in width and between 1/4 and 1 5/8 inches thick, at speeds up to 35 books per minute.
The casing-in machine came into existence in the latter years of the ] 9th century, and its principal period of development occurred during the early years of the 20th century. (89 , 320 )
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