| 摘要 |
PCT No. PCT/SE97/00576 Sec. 371 Date Oct. 7, 1998 Sec. 102(e) Date Oct. 7, 1998 PCT Filed Apr. 9, 1979 PCT Pub. No. WO97/38827 PCT Pub. Date Oct. 23, 1997A safety device used in preloading of bolts for providing the bolts with an internal stress in a mounted condition, wherein a first end of the bolt is secured to a first element and extends through a second element, which clamps to the first element, and where a hydraulic preloading device is temporarily applied to a second end of the bolt for axially stretching the bolt to create the external stress. The safety device incorporates a safety tensile bar detachably fitted to the first end of the bolt, and extending through a central bore in the bolt, and further through the hydraulic preloading device while being held adjacent its opposite end in an expanding plug. The expanding plug is provided in a frictional contact with a sleeve, which guides the plug to create a counter hold for absorbing relieved energy in case of the breaking of the bolt during the preloading operation. |
