JACK… FOR NUTS

The so-called unusual mechanism established at the Irkutsk industrial College for tightening heavily loaded threaded connections of large diameter. Anyone who has had to screw up the nut of the bolt, under the head of which is placed a rubber washer must necessarily have resorted to little tricks: when it’s getting on bad, just click on the head — it will dig into the rubber, the bolt will move forward and rotate the key will be much easier. Paradoxically, this principle was put to the Irkutsk innovators in the basis of the work of this mechanism. When tightened heavily loaded threaded connections of large diameter Jack allows you to stretch the bolt or stud within the elastic deformation that provides the subsequent free rotation of the nut.

 

The Jack consists of three working columns, arranged circumferentially and bonded into a single structure carrier plate. Speakers play the role of the power element of the device. Made of steel with high coefficient of heat expansion nimble, they are able to significantly lengthen when heated from built-in inside the electric elements.

 

In operation, the Jack is set so that column like a tripod, rests in the detail around tighten the stud with nut. The stud is screwed on the fungus — to make full contact with the carrier plate of the Jack. Further, after activation of the electric heating elements of the column begin to elongate, resulting in the “Jack — fungus — stud” there is a force whose value depends on the stiffness of all structural members. Upon reaching the maximum heating temperature of the column nut on the stud wrong way to tight contact with the pressed part.

 

 

Fig. 1. “Stretching” the Jack

 

To remove the Jack when the column has cooled and released a puff of fungus. To accelerate this process in their shirt provided by the water. At high give tighten joints after cooling columns again to turn fungus from contact with the plate, re-heat power components and additionally tighten the nut.

 

Small size devices (225×235 mm) allow to produce multiple jacks group screw connections. The simplicity of the design and maintenance of the mechanism gives the opportunity to use it during the installation of various structures in the field.