| 摘要 |
A force multiplying device is provided for use in conjunction with a balancing system for moving a load from an elevated position and to a predetermined lower position. The balancing system includes an extendable cable with a free end adapted to be secured to and exert an upward force on the load. The device includes a base which is secured to the load and a first lever pivotally secured at an intermediate point to the base about a generally horizontal axis. A fixed length flexible member has one end secured to a fir st end of the lever and a second end fixedly secured to a support position abov e the load. The length of the flexible member is such that the flexible member is in a fully extended position when the load is in the predetermined lower position. An elongated rocker arm has a first end in abutment with the base while the cable from the balancing system is secured to a second end of the rocker arm. A second end of the lever is pivotally secured to an intermediat e point of the rocker arm so that, as the load nears the predetermined lower position, the first end of the lever pivots upwardly and simultaneously pivo ts the second end of the rocker end downwardly to thereby exert an increased downward stroke on the cable, and a corresponding upward force on the load. By construction, the length of each rocker and lever arms is such that t he distance between the flexible member and the extendable cable is minimal. Furthermore, two systems like that can be symmetrically combined in such a way that the center of gravity of the load to be balanced remains in the sam e plane that the pair of flexible members and extendable cables, avoiding by that any swinging of the load during its entire stroke.
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