Sieve screen deck

A sieve screen deck, comprising a sloping, self supporting sieve screen having two opposed end edges, rapping or vibrating means to cause the sieve screen to vibrate, and a frame to which the sieve screen is connected, the sieve screen including sieving means defining a plurality of substantially parallel narrow slots and an array of backing bars connected to the sieve means which render the sieve screen self supporting, the sieve screen being connected to the frame only at or adjacent its two end edges and at least one of the connections being through a resilient means allowing limited vibrational movement between the sieve screen and the frame, a side wall being provided substantially along the full length on each side of the sieve screen spaced from and free of contact with the frame along the full length of the side walls and being of such a height so as to prevent material which is passing across the sieve screen between the two end edges from flowing over an edge of the sieve screen intermediate the said end edges, each side wall being formed of a resilient synthetic plastics material or rubber such that they do not impede substantially the ability of the sieve screen to vibrate and flex under the influence of the rapping or vibrating means.