Variable ratio drive mechanism
OwnerErnest Spiriginventor
Life of this patent
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Abstract
A variable ratio drive mechanism, suitable for a bicycle for example, has at least one gear whose effective radius is variable in a stepless manner in response to applied torque and/or in response to an external force. The gear may include a helical spring (10) which is "wound up" as torque is applied, to decrease its radius. Other possibilities include a rim (20) supported by spokes in the form of compressible springs (22), or a series of outwardly biased arcuate members (30) arranged around a central hub.
Claims19
A variable ratio drive mechanism including at least one gear in the form of a spiral spring whose effective radius is variable in a stepless manner, wherein torque is applied to or obtained from the gear by means of a belt or chain, the belt or chain having protrusions thereon, and the spiral spring is in the form of a strap having recesses therein arranged to cooperate with said protrusions.
A variable ratio drive mechanism including at least one gear having the form of a stiff circular rim mounted on an axle by means of radially extending compressible members, whereby the effective radius of the gear is variable in a stepless manner.
Dependencies are inferred from the claim text.