Patent ID: 6461263
Filing Date: 2002-10-08
Classification: F16G

Abstract:
A silent chain drive mechanism comprising:a larger sprocket having a plurality of spaced teeth; a smaller sprocket having a plurality of spaced teeth smaller in number than the teeth of the larger sprocket; and a silent chain wound around the larger sprocket and the smaller sprocket for transmitting power therebetween, the silent chain comprising a plurality of link plates interconnected by connector pins, each link plate having a pair of teeth; the link plate teeth having inside and outside flanks profiled to satisfy the expression Hc=Hf+Hs where Hc is the distance from the chain pitch line to the inside flank pitch line, Hf is the distance from the chain pitch line to the outside flank pitch line, the chain pitch line being an imaginary line passing though the centers of the connector pins, the inside flank pitch line being an imaginary line parallel to the chain pitch line and intersecting the inside flanks at points where the distance between adjacent inside flanks is Â½ the chain pitch, and the outside flank pitch line being an imaginary line parallel to the chain pitch line and intersecting the outside flanks at points where the distance between adjacent outside flanks is {fraction (3/2)} of the chain pitch, and Hs is defined by the equation Hs=P2&it;(1sin&it;â€ƒ&it;(Î¸2)-1tan&it;â€ƒ&it;(Î¸2))where P is the chain pitch measured on the chain pitch line between centers of successive connector pins, and &thgr; is an angle greater than the angular pitch of the teeth of the larger sprocket but not exceeding the angular pitch of the teeth of the smaller sprocket, the larger and smaller sprockets having tooth flanks having an involute curve profile satisfying the expression A1>Ac&gE;A2where A1 is the pressure angle of the larger sprocket, A2 is the pressure angle of the smaller sprocket, and Ac is the pressure angle of the inside flanks of the link plate teeth of the silent chain, whereby, as the chain meshes with either of said sprockets, the inside flank of a link plate adjacent to the free span of the chain approaching the last-mentioned sprocket, and the outside flank of a preceding seated link plate seated on the last-mentioned sprocket, concurrently mesh with the same sprocket tooth, thereby keeping the free span of the chain substantially free of up and down movement due to polygonal motion of the chain.