rounding and backing machine
A bookbinding machine which performs the two
operations of rounding the spine of a text block
and forming the shoulders for the boards. The book
is placed in the machine fore edge down, and is
drawn along until it arrives over a forming bar,
where it is gripped between facing rollers
revolving in opposite directions while the bar is
pushed up against the fore edge. The two sides of
the text block are dragged downwards while the
middle is being pushed up, forming an arc of
approximately one-third of a circle. The text
block is gripped between jaws that serve the same
function as the backing boards in hand backing,
and a rocker above swings in an arc against the
spine, finishing off the rounding and forming the
shoulders. The rocker is a heavy piece of metal
with a concave edge, and is brought down until the
concave is in contact with the spine. In library
binding, the rounding and backing machine operates
in a similar manner, except that each book is
inserted by ha nd, fore edge up, and the mechanism
must be adjusted to the r,J., thickness of each
book. The text block is both rounded and backed by
the action of the concave rocker arm. (203 , 320 , 339 )
![[CoOL]](/icons/sm_cool.gif){kind=icon}