振发滑车生产的滑轮组质量保障！

滑轮组：由定滑轮跟动滑轮组成的滑轮组，既省力又可改变力的方向.滑轮组用几段绳子吊着物体，提起物体所用的力就是总重的几分之一.绳子的自由端绕过动滑轮的算一段，而绕过定滑轮的就不算了.使用滑轮组虽然省了力，但费了距离，动力移动的距离大于重物移动的距离.Quality assurance of pulley block produced by Zhenfa pulley!Pulley block: a pulley block composed of a fixed pulley and a moving pulley, which saves labor and can change the direction of the force. The pulley block uses several sections of rope to hang the object, and the force used to lift the object is a fraction of the total weight. If the free end of the rope bypasses the moving pulley, it will be counted as a section, but it will not be counted if it bypasses the fixed pulley. Although using the pulley block saves labor, it costs distance, and the distance of power movement is greater than the distance of weight movement