Retractor for seat belt with an alleviating device

A retractor for a seat belt which is provided with a tension alleviating device, comprising a webbing take-up shaft biased in webbing take-up direction and rotatably supported on a base, a gear train consisting of a first gear member mounted on said take-up shaft for rotation therewith and a second gear member meshing with said first gear member and rotatably provided on said base, the second gear member having a greater number of teeth than the first gear member, a disc with a cam portion provided for rotation with said second gear member by frictional engagement therebetween, and a latch member movable between an engaged position in which it is engaged with a portion integral with said gear train and prevents rotation of said take-up shaft in the webbing take-up direction and a non-engaged position in which it is disengaged from said portion integral with said gear train, said latch member being biased toward said engaged position,

• said disc with a cam portion having a generally circumferentially extending first guide portion for guiding said latch member from said engaged position to said disengaged position upon draw-out of webbing, a second guide portion for guiding said latch member to said disengaged position short of said engaged position upon take-up of the webbing with said latch member remaining disengaged from said portion integral with said gear train and for holding said latch member in said disengaged position, said second guide portion being turned back from a terminal end of said first guide portion and extending generally circumferentially beyond a starting end of said first guide portion, and a third guide portion for guiding said latch member held in said second guide portion to said engaged position upon draw-out of the webbing, said third guide portion extending from the terminal end of said second guide portion to the starting end of said first guide portion.