由于重庆升降机间隙大、压力高，工作时承压时间长，沟槽内又没有挡圈，因此密封圈被挤入间隙并发生塑性变形。收腿时，挤出部分受到拉伸而撕裂，致使密封失效，这是就会出现大家所谓的“软腿”现象，但是支腿液压油缸磨损、老化也会出现这种问题。
Due to the large gap between Wenzhou freight elevators, high pressure, pressure at work long hours, and no retaining ring in the groove, it is squeezed into the gap and seal plastic deformation. When the legs, stretching out in part by tear, resulting in seal failure, it would appear everyone is so-called "soft legs" phenomenon, but the leg hydraulic cylinders wear and aging will face this problem.
      
在对货梯液压油缸反复多次的拆卸、修理和试验中发现，这种支腿液压缸存在着设计缺陷。液压缸的密封形式和密封间隙的设计是不合理的。该液压缸最大工作压力为3lMPa，活塞密封圈为Yx形。Yx形密封圈的最大承压能力一般不超过32MPa。而该液压缸的工作压力高达3IMPa，接近其极限压力，减缓了升降货梯的寿命。
In Wenzhou freight elevator hydraulic repeated disassembly, repair, and testing found that the outrigger cylinder design flaws exist. Seal the form and design of the hydraulic cylinder seal gap is unreasonable. The maximum working pressure of the hydraulic cylinder 3lMPa, piston seals for Yx shape. Yx-ring maximum pressure capacity of not more than 32MPa. The working pressure of the hydraulic cylinder up 3IMPa, close to its limit pressure, slowing cargo lifter life.