Patent ID: 8529389

Claim:
A chain and sprocket drive system comprising: a sprocket comprising a plurality of teeth, wherein each tooth comprises an engaging flank and a disengaging flank; an inverted tooth chain meshed with the sprocket, said inverted tooth chain comprising a plurality of rows of links that each articulate relative to a preceding link row about a leading pin center and that each articulate relative to a following link row about a trailing pin center, wherein said leading and trailing pin centers are spaced from each other at a chain pitch P, each of said rows comprising leading inside flanks and trailing outside flanks, wherein: the leading inside flanks of each row project outwardly relative to a working portion of the trailing outside flanks of a preceding row and comprise an inside flank radius R; said chain approaches said sprocket along a tangent line and the engaging flank of each sprocket tooth makes initial meshing contact with said chain at an initial contact location on the leading inside flanks of a meshing row of said chain at an instant of initial meshing contact; at said instant of initial meshing contact, a chain row immediately preceding the meshing row includes a leading pin center that is located on a pitch diameter of the sprocket so as to be a controlling pin center; for each row of said chain that is fully meshed with said sprocket, its leading and trailing pin centers are located on the pitch diameter PD and its trailing outside flanks are in contact with one of said engaging flanks; a meshing contact angle Tau (τ) is defined between the tangent line TL and an initial contact reference line that passes through both the controlling pin center and the initial contact location; a link plate entrance angle Beta (β) is defined between the initial contact reference line and an inside flank reference line that passes through an arc center of the inside flank radius and the initial contact location; a meshing impact angle Sigma (σ) is defined between the tangent line and the inside flank reference line such that σ=τ+β, and σ≦34°; said initial contact location is spaced by an initial contact distance IC D from a pin center reference line that extends between the leading and trailing pin centers of the meshing link row, wherein 0.49P≦IC D ≦0.53P; the leading inside flanks of each row project outwardly relative to a working portion of the trailing outside flanks of a preceding row by a maximum projection amount Lambda (λ) such that 0.007P≦λ≦0.017P; and, said outside flank comprises a non-working portion comprising a chamfer located between the working portion and a toe tip for each of said inside links of said chain, wherein the leading inside flanks of an adjacent row of said chain project outwardly relative to the chamfer by a projection amount that is greater than said projection amount Lambda (λ) when said inverted tooth chain is pulled straight.