Dowels for concrete acquired an extensive distribution as a mounting base for the use of screws and anchors. Such elements are classified into types according to the strength of concrete, as the quality of fastening depends on their quality. The concrete base can be heavy and light (porous), while the latter has a low resistance to compression, and heavy - on the contrary, for this reason it can be under pressure for a long time.
The principle of the dowel has a similarity with the wedge. On the case there are antennae located opposite the reverse stroke, thanks to which it cannot be pulled out after mounting into the wall. The final and complete consolidation occurs after the screw is inserted into it. Due to wedging the mount for many years securely held in the wall.
The material used to make the dowel depends on the mass of the object that requires fixing. Plastic dowels are suitable for plastic constructions of small sizes, for example, furniture. Steel options are used for more impressive objects, their principle of operation is similar to the plastic element.
Scope of use
The purpose is fasteners plumbing fixtures, pipelines, electrical equipment. It is necessary to pre-drill a hole of a suitable size, which is noted in the instructions for use, to clean the fine dust, only after that the dowel and anchor are inserted.
If it is necessary to hang a heavy load on a concrete base, the maximum diameter of the screw is used. It is important that the dowel length ratio is maintained for a certain operating load and the correct selection of the fasteners themselves, since they must be somewhat longer.
Yesterday and today
Prior to the invention of such devices used "tube" of wood. It was inserted into a dry hole, either smeared with glue, cement mortar or alabaster. This design did not differ in durability and reliability, due to the shrinkage of the solution and the drying out of the tree.
Currently, for the manufacture of dowels for concrete, high-quality plastic (for example, polyethylene) is used, or steel in combination with bearing parts (screws, nails and their variations) with a resistant coating that prevents corrosion or made from stainless steel.
Dowel-nail is the easiest option. Unlike standard nails, the screwing method is used to install it.
According to the method of use, all elements are divided into two groups. Standard dowels are inserted into the drilled (drilled) holes in the base without fixed structures.
Due to the fact that this technique is used only in two places of installation, due to the inconsistency of the holes of the part and the array, frame dowels are produced, implying simultaneous development of the base and the structure. This eliminates the possibility of mismatch.
Such options have found their application in a wide range of works, but the greatest efficiency is noted in the installation of door and window frames in hollow and solid foundations. Also due to their use there is the possibility of quick dismantling while maintaining the same type of box.
Conventionally, the dowel construction is divided into two groups of application:
- with anchoring fixture principle for multi-hollow and laminated wall constructions;
- Expansion options for walls of massive appearance.
The new system is intended for use in industry and everyday life. It has gained wide distribution due to its distinctive technical properties, high workability and ease of use.
Hilty's chemical anchor is used for core support parts for various purposes. Composite material created from synthetic durable resin provides sufficient strength. Among the distinctive characteristics it is worth noting a significant increase in the level of quality of elements under tension and fracture. Chemical properties improve the quality of the installation of steel products and exceed the standard options. Such results can be achieved by excellent adhesion of the core and base, with a frozen composition of synthetic resin.
Chemical two-element anchor Hilty allows you to mount elements with a large weight on any concrete and stone planes. A high level of sealing is an added advantage. This plays a special role when operating in conditions of high humidity. Some types of bases do not allow the formation of high-quality fastening of metal products using steel or plastic dowels. This applies to loose construction materials, among which is natural stone, hollow brick and aerated concrete.
Dowels intended for heavy loads are made of metal alloys and are equipped with threaded elements (bolts and studs). They are suitable for installation of a lifting hoist, gate for garages, and also sun-protection awnings. In accordance with safety precautions, metal versions must be used to secure the suspended ceiling, since plastic may melt during a fire and the ceiling will be threatened.
Elements for a porous material can be mounted without drilling holes. The dowel for concrete and brick easily enters the wall with a standard screwdriver due to a large thread on the outside and a point that has a similarity to the first drill.
A characteristic feature is the design. It is an indiscriminate element with longitudinal projections. The latter are necessary to prevent turning. There is also a stopper board and folding fastening ribs. The ribs extend the plane of contact with the support, and the side does not allow to fall into the existing hole. This option has become widespread in mounting baseboards, shelves and lighting elements. Standard sizes of this type of dowels are 14x35 and 5x25 mm.
Dowel for foam and aerated concrete
It has high edges, significantly increasing the area of the connection of the hole and the element. This requires the preliminary manufacture of holes.
Nylon classic dowels for concrete, the price of which starts from 200 rubles for 100 units, which are most widely used, allow us to get rid of the main part of the mounting difficulties. They are suitable for all wall constructions and are used with screws with sizes up to 15 mm.
The dowel is held in the hole of the corresponding diameter with the help of the antennae facing backwards, after wedging it is held tightly with the existing large teeth.
Also traditional elements are dowels used for aerated concrete. Holes are drilled for them according to their core diameter. The fastener is hammered into the hole with a hammer, the retention at the base is ensured by wedging the screw and the presence of ribs in the form of a spiral.
A distinctive feature of the universal dowels is that when attached to a hollow base, they “calculate” the hollow space. Anchor dowel for concrete expands in the cavity and is fixed in it. When used in a concrete or brick base, it opens tightly to the walls of the bore hole after unclamping.
Proper use of dowels for concrete requires the selection of a suitable drilling, mounting equipment. During the work, it is important to track the perpendicular direction of the drill to the material, while using a worn drill or not suitable for a particular base is prohibited.
The cut hole must be thoroughly cleaned from dust and residues. The importance of matching the depth and diameter. Drills produced for the production of solid type building materials should not be used for plates and sheets. Work with aerated concrete are characterized by reaming holes of a smaller size, as compared with the dowel itself.