Belt cleaner

1. A belt cleaner including one or more cleaner units mounted on a frame extending in a transverse direction of a conveyor belt, whereby leavings stuck on a belt surface are scraped off by a scraping portion provided at a top portion of said cleaner unit characterized in that:

said cleaner unit ( 6 ) comprises a support plate ( 8 ) providing said scraping portion ( 7 ), an upper resilient block ( 9 ) supporting resiliently a lower portion of said support plate, a lower resilient block ( 10 ) supporting resiliently a bottom of said upper resilient block ( 9 ), and a rigid plate ( 15 ) provided between said upper resilient block ( 9 ) and said lower resilient block ( 10 ), said rigid plate ( 15 ) being arranged along a sloping plane (HP) that rises in a direction (B) toward the rear of the cleaner unit and which follows a belt running direction,

wherein said support plate ( 8 ) is supported by said upper resilient block ( 9 ) in such manner that said support plate ( 8 ) is held in a forward leaning posture along a tilted plane (VP) inclining towards a front direction (F) of the cleaner unit which opposes against a belt running direction (X) with respect to a vertical line (V) perpendicular to the belt surface,

wherein said upper resilient block ( 9 ) includes hypothetical pivot axis ( 21 ) and is constituted to be deformed resiliently when a pushing force in said belt running direction is applied to said scraping portion so that said support plate ( 8 ) shifts its posture to an upright posture from said forward leaning posture about said hypothetical pivot axis ( 21 ) to lift up said scraping portion ( 7 ), and

wherein said lower resilient block ( 10 ) is constituted to be deformed when a further pushing force in said belt running direction and/or in a downward direction is applied to said upper resilient block ( 9 ) which is compressed or deformed by said support plate ( 8 ) shifted to said upright posture so that said lower resilient block ( 10 ) allows said upper resilient block ( 9 ) to move downward in response to said further pushing force.

2. A belt cleaner according to claim 1 , wherein said lower resilient block ( 10 ) is provided with a concave ( 18 ) extending laterally through a back side (B) thereof to form an upper jaw ( 19 ) and a lower jaw ( 20 ) so that said upper jaw ( 19 ) may move towards said lower jaw ( 20 ) by resilient deformation of the lower resilient block ( 10 ).

3. A belt cleaner according to claim 2 , wherein said support plate ( 8 ) is held and substantially embedded in the upper resilient block ( 9 ) so that said upper resilient block ( 9 ) includes a resilient section ( 9 a ) in front side (F) and a resilient section ( 9 b ) in back side (B) at both sides of said support plate ( 8 ) respectively, and a thickness (T 1 ) of said front section ( 9 a ) and a thickness (T 2 ) of said back section ( 9 b ) are formed in condition of T 1 <T 2 .

4. A belt cleaner according to claim 3 , wherein modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are selected under condition of R 1 <R 2 , and thereby vibrations caused in said support plate ( 8 ) contacting with the belt surface may be absorbed by said upper resilient block ( 9 ) having said lower modulus of rebound resilience (R 1 ).

5. A belt cleaner according to claim 4 , wherein said upper resilient block ( 9 ) is formed of butyl rubber and said lower resilient block ( 10 ) is formed of natural rubber so that modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are constituted in condition of R 1 <R 2 .

6. A belt cleaner according to claim 2 , wherein modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are selected under condition of R 1 <R 2 , and thereby vibrations caused in said support plate ( 8 ) contacting with the belt surface may be absorbed by said upper resilient block ( 9 ) having said lower modulus of rebound resilience (R 1 ).

7. A belt cleaner according to claim 6 , wherein said upper resilient block ( 9 ) is formed of butyl rubber and said lower resilient block ( 10 ) is formed of natural rubber so that modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are constituted in condition of R 1 <R 2 .

8. A belt cleaner according to claim 1 , wherein said support plate ( 8 ) is held and substantially embedded in the upper resilient block ( 9 ) so that said upper resilient block ( 9 ) includes a resilient section ( 9 a ) in front side (F) and a resilient section ( 9 b ) in back side (B) at both sides of said support plate ( 8 ) respectively, and a thickness (T 1 ) of said front section ( 9 a ) and a thickness (T 2 ) of said back section ( 9 b ) are formed in condition of T 1 <T 2 .

9. A belt cleaner according to claim 8 , wherein modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are selected under condition of R 1 <R 2 , and thereby vibrations caused in said support plate ( 8 ) contacting with the belt surface may be absorbed by said upper resilient block ( 9 ) having said lower modulus of rebound resilience (R 1 ).

10. A belt cleaner according to claim 9 , wherein said upper resilient block ( 9 ) is formed of butyl rubber and said lower resilient block ( 10 ) is formed of natural rubber so that modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are constituted in condition of R 1 <R 2 .

11. A belt cleaner according to claim 1 , wherein modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are selected under condition of R 1 <R 2 , and thereby vibrations caused in said support plate ( 8 ) contacting with the belt surface may be absorbed by said upper resilient block ( 9 ) having said lower modulus of rebound resilience (R 1 ).

12. A belt cleaner according to claim 11 , wherein said upper resilient block ( 9 ) is formed of butyl rubber and said lower resilient block ( 10 ) is formed of natural rubber so that modulus of rebound resilience (R 1 ) of said upper resilient block ( 9 ) and modulus of rebound resilient (R 2 ) of said lower resilient block ( 10 ) are constituted in condition of R 1 <R 2 .