| 摘要 |
PURPOSE: To improve position detection accuracy and to avoid being influenced by mechanical restriction by providing two potentiometers with no terminal wherein a movable point is driven at different transfer ratio, and obtaining scale of a position based on a resistance value found from the position of movable contact point. CONSTITUTION: A screw spindle 50 is spirally engaged with a screw hole of an adjustment member, and when a gear 5, or the spindle 50 is rotated, a linear movement of the adjusting member is caused. The gear 5 drives movable contact points of the first and second potentiometers 8 and 11 through gears 6 and 9 and axes 7 and 10, respectively. At this time, when the maximum stroke of adjustment drive is set at 120mm, 10 rotations of the gear 5 causes 10 rotations of the movable contact point of potentiometer 8. Meanwhile, it causes 9.09 rotations of the movable contact point of potentiometer 11, and both the movable contact points return to a zero point position. That is, a resistance value between the movable contact point and a connection point returns to 0 ohm, and a value of difference found from the resistance values of both the potentiometers 8 and 11 show scale of the position. |
