Patent ID: 7441647

Claim:
A tensioning system for a cleaning blade for a conveying belt, the tensioning system comprising: a frame; a blade support that is movable around a first axis in a first direction to increase cleaning blade pressure and a second direction oppositely to the first direction to decrease cleaning blade pressure; and a ratchet system through which a position of the blade support can be maintained against movement in the second direction, the ratchet system comprising (a) a first ratchet assembly on one of the frame and blade support with at least one ratchet surface facing in a first circumferential direction relative to the first axis and (b) a second ratchet assembly on the other of the frame and blade support and comprising a first plurality of ratchet surfaces facing in a second circumferential direction oppositely to the first circumferential direction, at least one of (a) the at least one ratchet surface and (b) the ratchet surfaces in the first plurality of ratchet surfaces is defined by a non-metal material that deforms radially relative to the first axis as the blade support pivots in the first direction to allow the one ratchet surface to i) move circumferentially up to and sequentially past each of the ratchet surfaces in the first plurality of ratchet surfaces as an incident of the blade support moving in the first direction around the first axis and ii) abut one of the ratchet surfaces in the first plurality of ratchet surfaces to block movement of the blade support in the second direction around the first axis.