Bridge support lifting mechanism for splitting machine

The utility model discloses a bridge frame lifting mechanism for splitting machines. The utility model is composed of a bridge frame head, a supporting frame head, and a mainshaft, wherein, the mainshaft penetrates through the bridge frame head and the supporting frame head and is connected with the bridge frame head through a screw thread pair; the upper end of the mainshaft is provided with an eccentric wheel or a cam, and the upper end of the mainshaft presses against the eccentric wheel or the cam; a regulating wheel is additionally provided; as the mainshaft moves upwards, the positing part of the regulating wheel is clamped at the lower surface of the supporting frame head; a spring is fixed between the bridge frame head and the supporting frame head, and the mainshaft penetrates through the spring. The utility model has the advantages of simple structure, low manufacture cost, smooth action, low noise, and exact lift positions.