将千斤顶活塞杆升至起重高度一半位置 下降 (多极活塞杆型式升至最后升出

Raise the piston rod of the jack to half of the lifting height and drop it (the multi-pole piston rod type is raised to the stroke height position of the last rise of 1/2 amount), and apply the inspection rated load on the bearing surface of the jack, and measure it after 1 minute and 3 minutes The continuous descent of the piston rod should not exceed.

Raise the piston rod of the jack to half of the lifting height and lower it (multipole piston rod type is raised to the stroke height position of 1 / 2 of the last lifting level), apply the inspection rated load on the bearing surface of the jack, count after 1min, and measure the continuous lowering amount of the piston rod after 3min, which shall not exceed.

Raise the piston rod of the jack to half of the lifting height and lower it (the type of multi-pole piston rod is raised to the stroke height position of 1/2 of the last lifting level), apply the inspection rated load on the bearing surface of the jack, and measure the continuous lowering of the plunger rod after 1min and 3min.