Bar screen with screen cleaner for waste water treatment installations

In a bar screen with a screen cleaner for waste water treatment installations, embodying a carriage cooperating with means for movement upwardly and downwardly in guides extending parallel to said screen, a rake for cleaning said screen pivotally connected to said carriage by pivot arms with said rake being pivotable by means of said pivot arms between a first position of engagement with said screen and a second position of disengagement with and spaced from said screen, a foldable lever assembly pivotally connected to said carriage and pivotally connected to said pivot arms and movable in a path of movement from a fully extended position to a first folded position which correspond to said first and second positions, respectively, of said rake and a lower stop means mounted in the path of movement of said foldable lever assembly, said lower stop means for engaging and moving said foldable lever assembly from said first folded position to an intermediate folded position at the end of the downward movement of said carriage and before said lever assembly reaches said fully extended position with said rake being retained in said second position of disengagement during downward movement of said carriage and being pivoted by the change of position of said lever assembly into a partially engaged position until said lever assembly is moved to said fully extended position, a stop member means mounted near the lowermost point of travel of said lever assembly for engaging and pivoting said lever assembly to its fully extended position only during upward movement and after commencement of upward movement of said carriage and after said lever assembly has been moved into said intermediate folded position by said lower stop means, said stop member means also for providing that movement of said rake into said first position of engagement with said screen is only completed after commencement of upward movement of said carriage and said rake is positively retained in the position of engagement with said screen while said lever assembly is in said fully extended position.