Conveyor belt tensioner for an agricultural harvesting header

1. A conveyor belt tensioning arrangement for an agricultural harvesting header ( 102 ), said agricultural harvesting header ( 102 ) comprising a frame ( 105 ), a plurality of arms ( 202 ) pivotally coupled to the frame ( 105 ) to pivot up and down at their forward ends with regard to said frame ( 105 ) and extending forward from said frame ( 105 ), and a conveyor belt ( 108 , 112 ) disposed on said plurality of arms ( 202 ) to carry cut crop material, the tensioning arrangement comprising:

a roller ( 208 ) comprising a front end and a rear end and a central axis, wherein the conveyor belt ( 108 , 112 ) is wrapped around the roller ( 208 ) for approximately 180 degrees to form an end loop in said conveyor belt ( 108 , 112 );

an elongate roller carriage ( 228 ) comprising a front end and a rear end, said elongate roller carriage ( 228 ) being configured to support the roller ( 208 ) for rotation about the central axis, wherein the elongate roller carriage ( 228 ) comprises a front carriage guide ( 410 ) at the front end and a rear carriage guide ( 412 ) at the rear end;

front and rear guide members ( 224 , 226 ) fixed with respect to an endmost pivoting arm ( 202 A) of said plurality of arms ( 202 ), wherein the front guide member ( 224 ) supports the front carriage guide ( 410 ) and the rear guide member ( 226 ) supports the rear carriage guide ( 412 ), wherein the front and rear guide members ( 224 , 226 ) constrain the elongate roller carriage ( 228 ) to translate with respect to the frame ( 105 ) in a direction generally parallel to a direction of travel of the belt ( 108 , 112 );

an elongate tensioning beam ( 230 ), the tensioning beam ( 230 ) comprising a front end and a rear end, wherein a central portion of the tensioning beam ( 230 ) is coupled to a central portion of the elongate roller carriage ( 228 ) to apply pressure to the elongate roller carriage ( 228 ); and

a spring assembly ( 232 ) fixed to the endmost pivoting arm ( 202 A), said spring assembly ( 232 ) comprising a spring ( 240 ) disposed to apply pressure to the rear end of the tensioning beam ( 230 );

wherein the elongate roller carriage ( 228 ) defines an aperture ( 402 ), and further wherein a pin coupled to the elongate tensioning beam ( 230 ) is disposed in the aperture ( 402 ) to apply pressure to a surface of the aperture ( 402 ).

2. The conveyor belt tensioning arrangement of claim 1 , wherein the aperture ( 402 ) is a slot.

3. The conveyor belt tensioning arrangement of claim 2 , wherein the slot ( 402 ) extends generally parallel to the longitudinal axis of the roller ( 208 ).

4. The conveyor belt tensioning arrangement of claim 1 , wherein the aperture ( 402 ) is disposed closer to the rear end of the tensioning beam ( 230 ) than the front end of the tensioning beam ( 230 ).

5. The conveyor belt tensioning arrangement of claim 2 , wherein the tensioning beam ( 230 ) has a plurality of working positions in which it can apply tension to the conveyor belt ( 108 , 112 ) and further in which the roller ( 208 ) has a plurality of corresponding positions along said slot.

6. The conveyor belt tensioning arrangement of claim 1 , wherein the tensioning beam ( 230 ) is concave in a direction facing away from the elongate roller carriage ( 228 ).

7. The conveyor belt tensioning arrangement of claim 1 , wherein the front end of the tensioning beam ( 230 ) is pivotally coupled to the front guide member ( 224 ).

8. An agricultural harvesting header ( 102 ) comprising a conveyor belt tensioning arrangement, said agricultural harvesting header ( 102 ) comprising:

a frame ( 105 );

a plurality of arms ( 202 ) pivotally coupled to the frame ( 105 ) at the rear ends to pivot up and down at their forward ends with regard to said frame ( 105 ) and extending forward from said frame ( 105 );

a conveyor belt ( 108 , 112 ) disposed on said plurality of arms ( 202 ) to carry cut crop material;

a first roller ( 210 ) supporting a first end loop of the conveyor belt ( 108 , 112 ) for reversing the direction of said conveyor belt ( 108 , 112 ), said first roller ( 210 ) being supported on a first one of said plurality of arms ( 202 ); and

the tensioning arrangement further comprising:

a second roller ( 208 ) comprising a front end and a rear end and a central axis, wherein the conveyor belt ( 108 , 112 ) is wrapped around the second roller ( 208 ) for approximately 180 degrees to form a second end loop of the conveyor belt ( 108 , 112 );

an elongate roller carriage ( 228 ) comprising a front end and a rear end, said elongate roller carriage ( 228 ) being configured to support the second roller ( 208 ) for rotation about the central axis, wherein the elongate roller carriage ( 228 ) has front carriage guide ( 410 ) at the front end and a rear carriage guide ( 412 ) at the rear end;

front and rear guide members ( 224 , 226 ) fixed with respect to an endmost pivoting arm ( 202 A) of said plurality of arms ( 202 ), wherein the front guide member ( 224 ) supports the front carriage guide ( 410 ) and the rear guide member ( 226 ) supports the rear carriage guide ( 412 ), wherein the front and rear guide members ( 224 , 226 ) constrain the elongate roller carriage ( 228 ) to translate with respect to the frame ( 105 ) in a direction generally parallel to a direction of travel of the belt ( 108 , 112 );

an elongate tensioning beam ( 230 ), the tensioning beam ( 230 ) comprising a front end and a rear end, wherein a central portion of the tensioning beam ( 230 ) is coupled to a central portion of the elongate roller carriage ( 228 ) to apply pressure to the elongate roller carriage ( 228 ); and

a spring assembly ( 232 ) fixed to the endmost pivoting arm ( 202 A), said spring assembly ( 232 ) comprising a spring ( 240 ) disposed to apply pressure to the rear end of the tensioning beam ( 230 );

wherein the elongate roller carriage ( 228 ) defines an aperture ( 402 ), and further wherein a pin coupled to the elongate tensioning beam ( 230 ) is disposed in the aperture ( 402 ) to apply pressure to a surface of the aperture ( 402 ).