Wheel driving chain in Skylight operator

Looking for the part catching the chain in a skylight operator. As you can see in the pictures 2 of the ears are broken off. I am primarely looking for that wheel as the rest of the assembly is fine. The number printed on the piece is 30654. The window itself in approximately 25 years old. This is a guess. Seems to be a truth assembly but not sure. Assembly itself has number 45015 printed on it. Thank