Abstract: An anti-reverse actuator mechanism having an actuator defined by a coil spring (20) associated with the center shaft (15) of the reel and which has an end coil (90) extending therefrom to engage a part (92) of an anti-reverse pawl (70). The coil spring is mounted on structure associated with the center shaft including a pair of spacers (89,81) whereby, through frictional engagement, the coil spring is caused to rotate with the center shaft and rotation thereof causes positioning of the anti-reverse pawl. When the anti-reverse pawl reaches its operative position and its limit of travel, the coil spring slips relative to the center shaft.

Abstract: In an oscillograph, a roll of recording paper is supported on a rotatable shaft such that the strip of recording paper passes over a metering roller driven at constant speed by a drive motor. Means to brake the shaft and prevent overrun of the recording strip comprises a magnetic solenoid-operated cone brake, adapted to momentarily place braking effort to the shaft. The cone brake has an appropriate friction liner, and serves to stop the roll, and prevent overrun. The braking effect is controlled by an electrical circuit that provides braking current to the solenoid for a selected short interval of time, sufficient to brake and stop the roll. At other times, there is no power applied to the brake.