A crank-rack mechanism can realize theoscillating angle of the driven member to vary in verylarge scope and possesses a constant transmission angle. This paper analyses its transmission functions andthe limited oscillating angle of the output gear

presents a numerical iteration method which can designthis king of mechanism when the oscillating amgle ofthe output gear is given and gives a design example.Meantime two mistakes about limited oscillating angleformulas of the output gear of this kind of mechanismin the referneces [2]、[3] are pointed out.