Caterpillar treadmill

Abstract

A tread assembly includes two belts and many slats. Each belt includes apertures. Each slat includes a rigid element, two threaded bolts and a cushion. The rigid element includes two apertures, an external face, and an internal face in contact with the belts. Each of the threaded bolts includes a middle section and two terminal sections. The middle section is inserted in one of the apertures of the rigid element so that the threaded bolts cannot be rotated relative to the rigid element. The first terminal section is located on the external face of the rigid element. The second terminal section is inserted in one of the aperture of a one of the belts. The cushion includes an internal face in contact with the external face of the rigid element and an external face extending higher than the first external section of each of the threaded bolts.

1 . A tread assembly comprising:
 two belts ( 21 ) each of which comprises apertures ( 28 ); and   slats ( 22 ) each of which comprises:
 a rigid element ( 30 ) comprising two apertures ( 301 ), an external face, and an internal face in contact with the belts ( 21 ); 
 two threaded bolts ( 35 ) each of which comprises:
 a middle section ( 352 ) inserted in one of the apertures ( 301 ) of the rigid element ( 30 ) so that the threaded bolts ( 35 ) cannot be rotated relative to the rigid element ( 30 ); 
 a first terminal section ( 351 ) located on an external face of the rigid element ( 30 ); and 
 a second terminal section ( 353 ) inserted in one of the aperture ( 28 ) of one of the belts ( 21 ); and 
 
 a cushion ( 31 ) comprising an internal face in contact with the external face of the rigid element ( 30 ) and an external face extending higher than the first external section ( 351 ) of each of the threaded bolts ( 35 ). 
   
     
     
         2 . The tread assembly according to  claim 1 , wherein the apertures ( 301 ) of the rigid element ( 30 ) are polygonal apertures, wherein the middle section ( 352 ) of each of the threaded bolts ( 35 ) is a polygonal section inserted in the apertures ( 301 ) of the rigid element ( 30 ) so that the threaded bolts ( 35 ) are not rotatable relative to the rigid element ( 30 ). 
     
     
         3 . The tread assembly according to  claim 2 , wherein the first terminal section ( 351 ) of each of the threaded bolts ( 35 ) is an enlarged head that does not extend beyond the external face of the cushion ( 31 ). 
     
     
         4 . The tread assembly according to  claim 2 , wherein the second terminal section ( 353 ) of each of the threaded bolts ( 35 ) is a threaded section. 
     
     
         5 . The tread assembly according to  claim 1 , wherein the threaded bolts ( 35 ) are carriage bolts. 
     
     
         6 . The tread assembly according to  claim 1 , wherein the external face of the cushion ( 31 ) is an anti-skid face ( 311 ).