The manhole cover balancer must be convenient to operate when the manhole is opened and closed to ensure safety.
The manhole open-cover balancer comprises a combination frame, a scroll spring, a shaft, a shaft sleeve and a spring box. The inner ring end of the scroll spring is inserted into a groove around the shaft sleeve and is fixed internally, and the outer ring end is inserted into a flat straight groove of the spring box. One end of the shaft has a shoulder, the shoulder is a hexagonal head, the side of the shoulder has a pin hole, the convex table of the outer frame also has a pin hole, and the other end of the shaft has an elastic baffle groove; Insert the pin shaft into the pin hole aligned with the side of the outer frame boss; The outer frame is limited to the middle frame and spring box; The inner frame is connected through a small shaft at one end of the middle frame, the inner frame has a short cylinder inserted into the long round hole of the connecting plate of the middle frame, and the upper end of the long round hole is provided with an adjusting screw; The flat straight groove of the spring box is limited to the upper end face of the connecting plate of the outer frame; The shoulder of the spring box is limited by the lower end face of the connecting plate.
