FIELD: mechanical engineering; transport engineering. SUBSTANCE: invention relates to gear mechanisms designed for converting reciprocating motion into rotation and it can be used in drives of bicycles. Proposed mechanism contains post, driven gear wheel (ratchet), driving member executing reciprocating motion (slider or rocker) and intermediate member (pawl) hinge fastened on driving member to form gear meshing with ratchet. Pawl toothed rim designed for engaging with ratchet is made with pitch surface whose profile is logarithmic spiral with pole in pawl hinge joint. Pawl of mechanism can have lantern wheel gearing for engagement with ratchet, and pressure angle of α = 35°±5°. EFFECT: provision of constant pressure angle at working stroke of mechanism, improved quality of operation. 2 cl, 3 dwg
