Patent ID: 7442139

Claim:
A conveyance system comprising a pair of endless conveyor chains arranged in spaced, side-by-side, relationship along a conveying path having a first end and a second end, a pair of driving sprockets respectively in meshing engagement with the chains at said first end, and rotatable in a direction to drive said chains in a first direction along said conveying path, and a pair of driven sprockets, respectively in meshing engagement with the chains at said second end, and rotatable by said chains; wherein said chains are roller chains having rollers as sprocket-engaging members, or bushing chains having bushings as sprocket-engaging members, said bushings or rollers each having a uniform diameter; each of said sprockets has a plurality of teeth, with tooth gaps between successive teeth, and a pitch circle; the successive teeth of each sprocket have facing tooth surfaces which are continuous with, and connected to each other by, a gap bottom; the sprocket engaging members of each of the chains are engageable with the gap bottoms in the tooth gaps of the respective driving and driven sprockets of the conveyance system; the tooth form of each tooth of each of said sprockets has a front tooth surface and a rear tooth surface, the front tooth surface preceding the rear tooth surface in the direction of rotation of the sprocket, and the tooth form of each tooth of each of said sprockets has a portion at which the distance from the center line of the tooth to at least the front tooth surface of the same tooth, at a location radially outward from the pitch circle, is larger than or equal to the distance from the center line at the location of said pitch circle to the intersection of said pitch circle and said front tooth surface; each of said driving sprockets and said driven sprockets has a root diameter defined as the diameter of a circle tangent to the gap bottoms of the sprocket, and in which said root diameter is less than the difference between the diameter of said pitch circle and said uniform diameter of the bushings or rollers, less the lower deviation set forth in Tables 1 and 2.