由于重慶升降機間隙大、壓力高，工作時承壓時間長，溝槽內又沒有擋圈，因此密封圈被擠入間隙并發生塑性變形。收腿時，擠出部分受到拉伸而撕裂，致使密封失效，這是就會出現大家所謂的“軟腿”現象，但是支腿液壓油缸磨損、老化也會出現這種問題。
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.
      
在對貨梯液壓油缸反復多次的拆卸、修理和試驗中發現，這種支腿液壓缸存在著設計缺陷。液壓缸的密封形式和密封間隙的設計是不合理的。該液壓缸最大工作壓力為3lMPa，活塞密封圈為Yx形。Yx形密封圈的最大承壓能力一般不超過32MPa。而該液壓缸的工作壓力高達3IMPa，接近其極限壓力，減緩了升降貨梯的壽命。
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.