An expansion bolt consists of bolts, nuts, and sleeves. Sleeve expands when the bolt is tightened. They are similar to the nail-in anchor but are able to handle much heavier weight use like a podium and stadium seating.
There are multiple different types of expansion bolts provided. The definition of an engineering point of view is the machine is as follows: expansion bolts and nuts configuration that expands when tightened into the hole. Know more about the expansion bolts via http://www.asia-pacifics.com/products_brand/Binder%20Group.
The first is a bolt, nut combination arm lead, and taper. Nuts in the arms of the lead and everything is inserted into a hole drilled into the material that needs to be tied up.
Then there's the bolt, sleeve lead, metal cone, and nut combinations. Cones and lay down arms on the bolt assembly. As the bolt is tightened, it forces the metal cone into the sleeve which again causes the arm to expand and repair the equipment in place.
The common factor is the lead arm. This is what actually facilitates the expansion and allows the bolt to stay in place. The sleeve also protects the screw and the material from cracking due to too much pressure. It also reduces the possibility of the bolts getting pulled out or stripped.
The expansion bolts that are not complicated. They are basically a bolt in the sleeve that expands when the bolt is tightened. Expansion creates a safer bolt in the hole.
Expansion bolts can be used in the construction of the podium, permanent scaffolding, seating in the stadium and security in rock climbing routes.
They are fairly easy to use, all you need is a drill that is true, at most, only slightly larger than the bolt head and the bolt itself. Drill a hole into the material, insert screws and tighten. Be careful not to over tighten as to cause the bolt head bolt to get stripped, rendering it extremely difficult to remove, if not impossible.