fully open position as shown in fig1 finally when the pull chain 116 is pulled again the pawl 134 is allowed to rotate freely in the end of travel region 130 as shown in fig1 c when the pull chain 116 is subsequently released the force of the tension spring 144 which biases the louvers to the closed position being attached to the rectangular frame 18 and connecting rod 20 via pins 148 and 150 causes the louvers 18 to close and thus turn the pulley 104 counter clockwise as seen from the outer surface 146 of the pulley 104 fig1 d shows the orientation of the pawl against the teeth of the latch portion 126 while the louvers 18 are reverting to the closed position therefore the act of opening and closing the louvers 18 can be accomplished repeatedly in order to provide a more precise control over the airflow entering a room and thus increase the comfort level and energy saving capability afforded thereby the aforementioned embodiment teaches an ergonomically accessible air flow control mechanism for a register in which the louvers are springably biased in the closed position and held in the open position using a pawl and latch arrangement however it is well.