Currently, not a single construction or repair can do without the use of such a fastener as an anchor dowel. This is a metal part that is twisted, embedded or hammered into a pre-prepared hole in a solid base.
These fasteners are as much an integral part of construction and repair work as nails or self-tapping screws. The market is replete with various types of similar parts. What is an anchor, what types does it have and where is it used?
A bit of history
The first anchor was invented and patented by engineer D. Rawlings in 1913. And in 1958, his German colleague Arthur Fischer invented nylon sleeves for such fasteners. Before that, wooden "chops" were used.
What is this fastener?
Anker is translated from German as "anchor". This is a fastening element that is designed to hold any structures in load-bearing bases. The fastening of the anchor itself in the base occurs due to the expansion of the outer parts, by hammering or twisting into themdowel or bolt. Such elements provide a reliable and high-quality connection. They are able to withstand quite heavy loads.
Anchor dowel (GOST 28778-90) consists of two parts. This is a spacer and a non-spacer part. The first one is working. It expands in the process of hammering or twisting and thus provides a reliable fastening. 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, types of installation, materials of manufacture. The classification is pretty simple. So, according to the purpose, anchor dowels are divided into two types. The first is appointment by reason:
- 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. For fixing heavier structures made of sheet materials, it is necessary to use a dowel with an external thread. These elements are twisted into GKL sheets and subsequently securely hold any structures.
- For porous or cellular substrates. These are hollow bricks, cellular blocks, foam concrete, etc. These dowels are made of soft plastic materials. They have an extended spacer.
- For dense full-bodied materials. These include concrete, solid brick, stone, etc. Types of fasteners for such basescan be made of both metal and plastic. They have a long, non-expansion part.
As for the purpose of the application, in accordance with it, furniture, frame and facade dowels are distinguished. Particularly noteworthy are the elements for heat-insulating materials, in the jargon of builders they are called "mushrooms". These types of fasteners are made of plastic. They have a wide cap, designed to connect heat-insulating boards with the base. Facade and frame dowels have an elongated, non-expansion part. They are designed for fastening heavy structures. They are usually made of metal.
Materials of production
Different types of materials can be used in anchor dowel production technology. But most often it is steel or other alloys and plastics (nylon, polypropylene, etc.). As a rule, a metal anchor dowel is used for fastening heavy structures that will later bear loads. These can be windows, doors or elements of facade systems, as well as various structural elements. Steel anchors are also used for fixing foundation elements. They are made of alloy steels and are able to withstand heavy loads.
Plastic anchor dowels are used when mounting lighter structures. These are various objects from the profile for GKL. Anchors with nylon dowels have also found their niche in domestic applications. For example, they are used to fasten lamps, various decorative elements, paintings, linen cords and ropes. In such fastenerselements of the hat are replaced by hooks, rings and other elements for various needs. At the same time, plastic dowels are used for hollow or cellular bases.
Types of anchors by type of installation
They are different:
- Mortgage. Anchor fasteners, which are designed for heavy loads. Mounted in the frame of a building or wall during its construction.
- Spreader. Fastening metal knot, which is also designed for heavy loads. Popular in construction, finishing and repair work. It is mounted due to the friction force of the element installed in the structure (sleeve or spring ring), expanded by the translational movement of the bolt.
- Wedge. Fastens the parts to the base. It has a metal rod with a spacer: a coupling, a conical tail and a nut.
- Drive. These dowels use a nail with special notches that prevent it from coming out.
- Frame. Such an anchor dowel is used for fastening plastic and wooden frames. This is a light version of the fastener with a special head shape that allows you to align the fastening structure with the base.
Through-through installation
This method is used to fasten structural elements when the dowel passes through the "body" of the materials to be fixed. Parts for this method should have a small (short) spacer. It should be noted that special rules must be observed for through-hole installation. 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 inefficient.
Pre-mounting method
This option involves installing a dowel in the base for the full length. Mounting of fasteners is carried out in pre-drilled holes. Its diameter must match the diameter of the dowel. Length - 3-5 mm more. Such a margin is needed so that the dust and chips that form during drilling do not prevent the dowel from being completely immersed in it.
