| 摘要 |
A double pivoted cantilevered support arm with a lower arm 6 which has fixed discs at both ends, is pivoted at the centre of the bottom disc 5. The top arm 10 is pivoted at the centre of the top disc 7, and supports a lamp. The disc diameters are proportional in dimensions to the maximum balancing torque at their respective pivots. One tension spring 14 provides the balancing force for both arms, flexible strips 3 and 12 connected to the spring pass over the discs to anchor points 2 and 11. The tension in the flexible strips between the discs and the anchor points provides the reaction force to balance the arms. Moving the arms makes the flexible strips slide over the discs and causes the spring and friction forces to be adjusted, the friction force modifies the tension in the flexible strips to balance the arms. |
