is fixed to the u2018 v u2019 shaped chuck 4 3 and the other end of the round steel part 4 4 extends into the tube of the hollow steel part 2 3 and is fixed by a fastening bolt 2 4 and thereby the upper chuck 4 1 and lower chuck 4 2 are fixed to the third end of the upper u2018 y u2019 shaped bracket 2 1 and the third end of the lower u2018 y u2019 shaped bracket 2 2 respectively so that the rotary frame 2 and the chuck 4 are connected together during use the length of the round steel part 4 4 extending into the hollow steel tube 2 3 can be adjusted to regulate the extension length of the upper chuck 4 1 and the lower chuck 4 2 so as to secure the guide rail rope 5 as shown in fig4 when the rotary frame 2 rotates around the other end of the transverse supporting rod to a position where the lower chuck 4 2 is in a horizontal state the upper chuck 4 1 will be in an up tilting state at this point both the upper hydraulic supporting rod 3 1 and the lower hydraulic supporting rod 3 2 are in maximum extension state in addition since the hydraulic supporting rod 3 provides persistent and steady pushing force the moment of resistance to the other end of the transverse supporting rod of the u2018 t u2019 shaped mounting support 1 is negative here the moment in a counter clockwise direction is defined as positive therefore the rotary frame 2 cannot rotate and.