Currently, no construction or repair works without using such a fastener as an anchor dowel. This is a metal part that is twisted, laid or hammered into a pre-prepared hole in a solid base.
These fasteners are the same integral part in the construction and repair work, as nails or screws. The market is replete with various kinds of similar parts. What is an anchor, what types does it have and where is it used?
A bit of history
The first anchor dowel was invented and patented by engineer D. Rawlings in 1913. And in 1958, his German counterpart Arthur Fischer invented nylon sleeves for such fasteners. Prior to this, wooden "choppers" were used.
What is such a fastener?
Anchor is translated from German as "anchor". This is a fastener that is designed to hold any structures in the bearing bases. The anchor itself is fixed at the base by expanding the external parts by driving or screwing a dowel or bolt into them. Such elements provide a reliable and high-quality connection. They are able to withstand quite large loads.
Anchor dowel (GOST 28778-90) consists of two parts. These are spacer and non-spacer parts. The first is working. It expands in the process of clogging or twisting and thereby provides a secure fit. Also, the anchor dowel has a cuff that prevents complete immersion in the hole. It can be secret, have a different shape: round or cylindrical.
Types and classification of dowels
Anchor fasteners differ in purpose, type of installation, manufacturing materials. The classification is quite simple. So, according to their purpose, anchor dowels are divided into two types. The first is the appointment on the basis of:
- For sheet materials (plywood, OSB, GKL, chipboard). Such dowels are popularly called "butterflies" because of their characteristic shape. Such anchor fasteners are convenient for mounting lightweight structures on hollow walls. To attach heavier sheet metal structures, an external plug must be used. These elements are twisted into GKL sheets and subsequently reliably hold any structures.
- For porous or cellular substrates. Such are hollow bricks, cellular blocks, foam concrete, etc. These dowels are made of soft plastic materials. They have an elongated spacer.
- For dense corpulent materials. These include concrete, solid brick, stone, etc. Types of fasteners for such substrates can be made of both metal and plastic. They have a long, non-spacer part.
As for the intended use, in accordance with it, furniture, frame and facade dowels are distinguished. Of particular note are elements for heat-insulating materials, in the slang of builders they are called "mushrooms." These types of fasteners are made of plastic. They have a wide hat, designed to connect heat-insulating boards with the base. Facade and frame dowels have an elongated, non-spacer part. They are designed for fastening heavy structures. Made, as a rule, of metal.
Materials of manufacture
In the production technology of anchor dowels, various types of materials can be used. But most often it is steel or other alloys and plastic (nylon, polypropylene, etc.). As a rule, an anchor metal dowel is used for fastening heavy structures that will continue to carry loads. It can be windows, doors or elements of facade systems, as well as various structural elements. Steel anchors are also used to fasten foundation elements. They are made of alloy steels and are able to withstand heavy loads.
Plastic anchor dowels are used in the installation of lighter structures. These are various objects from the profile for the GCR. Anchors with nylon dowels have also occupied their niche in domestic use. For example, they are used for fastening fixtures, various decorative elements, paintings, linen cords and ropes. In such fasteners, hats are replaced with hooks, rings and other elements for various purposes. At the same time, plastic dowels are used for hollow or cellular substrates.
Types of anchors by type of installation
They are different:
- Mortgage. Anchor fasteners designed for heavy loads. Mounted in the frame of the building or wall in the process of its construction.
- Spacer. Mounting metal assembly, which is also designed for heavy loads. Popular in construction, decoration and repair work. It is mounted due to the frictional force of the element installed in the structure (sleeve or spring ring), bursting by translational movement of the bolt.
- Wedge. Fastens parts to the base. It has a metal rod with a spacer: a sleeve, a tapered tail and a nut.
- Clogged. In such dowels, a nail with special notches is used that prevents its return exit.
- Frame. This anchor dowel is used for fastening plastic and wooden frames. This is a lightweight version of the fastener with a special shape of the head, which allows you to compare the mounting structure with the base.
End-to-end installation method
This method is used to fasten structural elements when the dowel passes through the “body” of the materials being fixed. Details for this method should have a small (short) spacer. It should be noted that during end-to-end installation, special rules must be observed. The anchor dowel must be so long that 2/3 of it is at the base, and 1/3 is in the body of the structure. Otherwise, this installation method is ineffective.
Preliminary installation method
This option involves installing the dowel in the base for the entire length. Fasteners are mounted in pre-drilled holes. Its diameter should correspond to the diameter of the dowel. Length - 3-5 mm more. Such a supply is necessary so that the dust and crumbs that are formed during the drilling of the hole do not impede the dowel's full immersion in it.