Types of anchors: correct fastening

Recommendation points

• Anchor bolt with nut
• Wedge anchor
• Ceiling anchor with ring (eyelet)
• anchor bolt
• Double-expansion anchor
• Expanding anchor
• Frame anchor
• Nail anchors
• Driven anchor
• Screw anchor

If we talk about the reliability of fasteners for bricks and concrete, then an anchor is preferable than a dowel. The main “holding force” for him is not friction, but the resistance of the material to destruction. And these forces are switched on thanks to a kind of anchor, which is formed due to the section of the sleeve weakened by the slots.

Anchor bolt with nut

Despite the name, in fact, this type of fastener is a threaded rod with a wedge in a metal sleeve. In the central part of the sleeve there are sealing beads and four “windows” with slots up to the wedge. And as a “mover” that brings the anchor into working condition, a nut is used.

The dimensions of the wedge are selected in such a way that the diameter of the base of the cone is equal to the outer diameter of the sleeve, and the “narrow part” coincides with the diameter of the stud.

Installation is simple:

• drill a hole (with a diameter slightly larger than that of the sleeve), and clean it;
• drive in the anchor bolt until the washer stops in the base;
• turn the nut clockwise;
• the hairpin moves outward, and the sleeve remains stationary due to the influx;
• the wedge retracts into the sleeve and expands the cut petals.

The anchor with a countersunk head also works. The role of a nut with a washer is played by a hollow cylinder with an internal thread, which looks like a corresponding screw for a Phillips screwdriver.

Wedge anchor

To some extent, this type of anchor resembles the previous one, but it has a short sleeve put on a hairpin in front of the wedge.

Principle of operation: the sleeve “sits” tightly in the hole, and when the nut turns, the pin moves, which draws in the wedge and expands the blades of the sleeve.

Ceiling anchor with ring (eyelet)

This is a type of wedge anchor. The difference is that the clutch petals move apart not under the action of the rotation of the pin with the wedge, but under the effort to pull the anchor out of the ceiling.

anchor bolt

The metal coupling of this type has the same device as that of the anchor bolt with a nut – a hollow cylinder with four windows and slots up to a wedge. But a flare nut is used as a wedge. The wedge is pushed into the clutch by turning a regular hex bolt.

In addition to the hex head for the wrench, the bolt can have a mounting “shank” in the form of a ring or a hook.

Double-expansion anchor

This is a reinforced version of the anchor bolt.

Differences:

• two couplings are put on a metal rod (hairpin) with a slot for the slot;
• the short sleeve enters the long one with a taper;
• when screwing in the nut, the short sleeve is expanded with a flare nut;
• the long sleeve slides over the short one, which serves as a spreading wedge for it.

In addition to this option, these anchors can be terminated with a fixing hook or ring.

Expanding anchor

The sleeve of this anchor is made in the form of a hollow cylinder with four wide slots at the end and a locking flat spring that holds the petals in their initial position. Inside the sleeve there is a tetrahedral element, each face of which fits into its own slot. And so that the element does not fall out of the anchor before installation, each petal ends with a small side.

The type and length of the bolt are selected for the sleeve. It can be a regular hex head bolt.

Stud with hook or ring shank and nut.

When screwing in the bolt, the square element expands the sleeve segments.

Frame anchor

The main purpose is through fastening to the base of window frames and door blocks.

The sleeve has slots on the bevel nut side and on the screw head side. When the screw is screwed in, the anchor is “anchored” from both sides. And special ribs prevent the sleeve from turning with the screw.

Nail anchors

This type has the shape of a hollow nail with a slot, into which a semicircular wedge is driven.

Another variety is slightly different – there are four slots, and the wedge itself has the shape of a nail.

Driven anchor

A small sleeve with a tapered inner cavity and thread. Four grooved slots at the end.

The anchor is driven into the hole using a special nozzle, and then a bolt or screw is screwed in.

Screw anchor

Special type for fixing parts in weak substrates (in building blocks with high voids).

The sleeve has slots weakened at the top and in the middle, at the end it ends with a nut.

When screwing a screw into a nut, the sleeve is deformed, the lamellas expand as far as the hollowness of the base allows and form a retaining “belt”.