A positive locking roller stop device includes two parallel disks; one is attached in a fixed position on a shaft while the other is mounted to same shaft via a bearing, allowing for rotation of this disk independent of the rotation of the shaft. One disk has one or more spring arm rollers attached to surface facing the second disk which has either an inclined notch(es) or inclined ramp(s) positioned to face the other disk and spring arm roller. Spacing between the disks allows the spring arm roller to engage the inclined notch(es) in the other disk when rotated in one direction thereby locking the movable disk to shaft while allowing free rotation of movable disk around shaft when rotated in opposite direction.