A chain conveyor for conveying a plurality of empty articles along a path (P), comprising: - a plurality of rollers adapted to roll onto a guide and about an axis (A); - a plurality of axles about which said respective rollers are rotatably mounted, like bushes ; - a plurality of first and second links (35; 36, 38) for connecting respective pairs of subsequent axles or bushes ; and - a plurality of conveying beams for said articles , which are supported at least indirectly by said relative axles or bushes ; each said roller comprising a radially inner surface which rotates, in use, onto a radially outer surface of said respective axle or bush ; and comprising a sensor , which is configured for generating a signal, which is associated to the radial gap due to the wear between said inner surface of said roller and said outer surface of said bush , characterized in that the sensor senses the distance (H) between said sensor and reference surface directly or indirectly connected to relative said axles or bushes such that said signal generated by said sensor is associated to the distance (H) between said sensor and reference surfaces directly or indirectly connected to relative said axles or bushes ; said reference surfaces being carried by said first links and being radially opposite to said relative axles or bushes , and said distance (H) being measured orthogonally to said path (P) and said axes (A). - a plurality of rollers adapted to roll onto a guide and about an axis (A); - a plurality of axles about which said respective rollers are rotatably mounted, like bushes ; - a plurality of first and second links (35; 36, 38) for connecting respective pairs of subsequent axles or bushes ; and - a plurality of conveying beams for said articles , which are supported at least indirectly by said relative axles or bushes ; each said roller comprising a radially inner surface which rotates, in use, onto a radially outer surface of said respective axle or bush ; and comprising a sensor , which is configured for generating a signal, which is associated to the radial gap due to the wear between said inner surface of said roller and said outer surface of said bush , characterized in that the sensor senses the distance (H) between said sensor and reference surface directly or indirectly connected to relative said axles or bushes such that said signal generated by said sensor is associated to the distance (H) between said sensor and reference surfaces directly or indirectly connected to relative said axles or bushes ; said reference surfaces being carried by said first links and being radially opposite to said relative axles or bushes , and said distance (H) being measured orthogonally to said path (P) and said axes (A). comprising a sensor , which is configured for generating a signal, which is associated to the radial gap due to the wear between said inner surface of said roller and said outer surface of said bush , characterized in that the sensor senses the distance (H) between said sensor and reference surface directly or indirectly connected to relative said axles or bushes such that said signal generated by said sensor is associated to the distance (H) between said sensor and reference surfaces directly or indirectly connected to relative said axles or bushes ; said reference surfaces being carried by said first links and being radially opposite to said relative axles or bushes , and said distance (H) being measured orthogonally to said path (P) and said axes (A). <EOS>