UNCOUPLING PULLEY HAVING A SPIRAL SPRING

摘要

The invention relates to an uncoupling pulley which includes a hub (3) to which an inner end of a spiral spring (5) is secured, as well as a rim (1), and which also includes a load bracket ensuring relative rotation of the rim and the hub, in which: the spiral spring (5) has an outer end (52) which comprises a bearing surface (53) aligned with the outer surface (54) of the spring (5) and pointing towards the outside; the rim has a drive stop (151) engaging with the bearing surface (53) to drive the spiral spring (5) upon closing in a first direction of relative rotation between the rim (1) and the hub (3); an abutment element for limiting the amplitude of movement of the spiral spring (5) to a non-zero angular travel a1 when closing; and said spring comprises at least one abutment (66, 66') rotatably secured to the hub (3) and having at least one abutment surface engaging with at least one first surface of an abutment (16) of the rim (1) in order to limit the angular displacement of said drive stop (151) to an angular travel a2 > 0 in a second direction of relative rotation between the rim (1) and the hub (3) from a position in which the drive abutment (151) is in contact with the bearing surface, but in which the spiral spring is free.