Not only fitter or installer, but any technician knows to connect the two parts with the bolt, insert it through the hole, then throw the washer and finally screw and tighten the nut. As you can see, thus there is a double work: there is not only the Assembly of parts but also the Assembly of the bolt.
But such a bolt, like the one shown in the figure, it is possible to use already assembled, that is with a plastic washer and nut. No accident that he recognized the invention and the design of the issued copyright certificate № 521406. How to connect the parts, if nut already on it?
1 — head slotted, 2 — expansion rod, 3, 4 — washer with nut, 5 — shank stud.
It is a very simple and, most importantly, twice as fast. The fact that the head of his split, in the form of a collet, and the inside is a rod having an expansion element and the thread and the shank of the key. While the rod does not polvinen, the collet head is not expanded, its diameter is the same as the body of the bolt, and therefore, it is not difficult to pass through the holes of the parts. Then the rod is tightened over the shank, and the head expands. Enough now finally tighten the nut, and the parts are connected.