目前,国内外掩护式液压支架,为了使支架在高度发生变化时,顶梁端点和煤壁之间的距离近于不变,广泛采用了四连杆机构。该机构的采用,使支架在工作过程中,顶梁端点的实际运动轨迹是一条如图1所示的abcd曲线(梁端运动曲线以下简称曲线)。这条曲线对支架的受力状态有较大的影响,特别值得注意的是,目前支架经常工 At present, the domestic and international cover hydraulic support, in order to make changes in the height of the support, the distance between the end of the top beam and the coal wall is almost constant, widely used four-bar linkage. The use of the agency, so that the stent in the course of work, the actual trajectory of the top beam is an abcd curve shown in Figure 1 (beam-side motion curve hereinafter referred to as the curve). This curve has a greater impact on the force state of the stent, it is noteworthy that the current stent often work