DE9404499U1 - Foldable fastener - Google Patents

Description

· t

fish r works

Artur Fischer GmbH & Co. KG

72176Waldachtai

M 1783 16 March 1994

Impact fastener

The invention relates to a fastening element according to the preamble of claim 1.

DE 33 45 331 A1 discloses a fastening element designed as a nail, which has an expansion area in the area of its front nail face, which is formed by two spaced-apart, outwardly curved legs. Anchoring of such a fastening element takes place in such a way that its shaft is driven into a pre-drilled hole in a masonry or similar. When the shaft is driven into the hole, the expansion legs are pressed inwards by the hole wall, whereby an insert located between the expansion legs can generate increased pressure from the expansion legs against the hole wall. After driving in, the expansion legs of the fastening element are pressed against the hole wall by the plastic and/or elastic restoring force of the insert, whereby a correspondingly high holding force is achieved. However, due to the insert, the driving resistance of the known nail is very high.

However, the known hammer-in fastening elements are often only suitable to a limited extent for use in porous masonry, as the expansion capacity of the insert is limited.

The invention is based on the object of creating a fastening element that can be driven into a drill hole in a masonry wall and which achieves good holding values even in porous masonry.

The solution to this problem is achieved by the features specified in claim 1. The fastening element has an expansion body that can be driven into a longitudinal slot in the shaft and is supported in longitudinal grooves in the shaft via webs protruding from it. As soon as the expansion body comes to rest on the bottom of the borehole, two opposing expansion legs slide onto the expansion body and are driven into the borehole wall. In this way, a positive connection is created between the masonry and the fastening element, specifically in the area of the expansion legs.

It is particularly advantageous to provide a pre-expansion safety device on the shaft in the form of notches on the side edges of the longitudinal grooves. These notches initially form a stop for the webs protruding from the expansion body when the fastening element is driven in. However, as soon as the expansion body comes into contact with the bottom of the hole, this stop is overcome, i.e. the webs push the notches back slightly and move between the notches with a corresponding friction force until the end position is reached, where the expansion legs have reached their maximum expansion. Even in this expanded position, the notches continue to press against the webs protruding from the expansion body, so that the notches create a mechanical connection between the shaft and the expansion body. The connection thus achieved between the expansion body and the shaft ensures that the shaft with its expansion legs cannot be pulled off the expansion body under tensile stress.

The notches in the area of the longitudinal grooves of the shaft prevent unwanted pre-expansion during the driving in of the fastening element and on the other hand these notches ensure that a mechanical connection exists between the shaft and the expansion body in the expanded position.

The expansion body is preferably designed as an expansion cone. The fastening head of the fastening element can be designed as a nail head or as a threaded pin, depending on the application.

The invention is explained in more detail below with reference to embodiments shown in the drawing.
35

Show it:

Figure 1 a fastening element with a nail head together with the associated expansion body,
5

Figure 2 shows the fastening element of Figure 1, but rotated by 90° and with

a threaded pin instead of the nail head,

Figure 3 the fastening element according to Figure 1 with attached expansion body

and

Figure 4 shows the fastening element according to Figure 1 in a borehole of a

Masonry with spread expansion legs.

The fastening element shown in Figure 1 consists of a shaft 1 with a fastening head designed as a nail head 2 and of an expansion body 3 from which webs 4, 5 (Figure 2) protrude. The webs 4, 5 can be inserted into corresponding longitudinal grooves 6, 7, both of which are shown in the longitudinal section in Figure 2. At the free shaft end 8, the shaft 1 has a short longitudinal slot 9, which merges into the two longitudinal grooves 6, 7.

The design of a fastening element shown in Figure 2 differs from that in Figure 1 only by a different fastening head, which here is designed as a threaded pin 10 instead of the nail head 2. Both designs have an expansion body 3 designed as an expansion cone, from which the webs 4, 5 protrude like forks in the direction of the longitudinal grooves 6, 7. Notches 11, 12 are formed on the longitudinal grooves 6, 7 as a pre-expansion safeguard, against which the end 13 of the webs 4, 5 inserted into the longitudinal grooves 6, 7 rest, as shown in Figure 3.

Figure 3 shows the pre-assembled fastening element with the expansion body 3 attached.

The webs 4, 5 can lie in the longitudinal grooves 6, 7 with little tension, so that the expansion body 3 with the webs 4, 5 protruding from it cannot accidentally fall off the fastening element.

If the fastening element is driven into a drill hole 14 in a masonry 15 as shown in Figure 4, the expansion body 3 first comes into contact with the base of the drill hole 17 with its front face 16. By means of strong hammer blows on the nail head 2, the mechanical resistance exerted by the notches 11 is then overcome until the shaft has reached the position shown in Figure 4, in which

the expansion legs 18, 19 are pushed onto the expansion body 3 and engage laterally in the masonry 15 in a form-fitting manner. In this position, the deformed notches 11, 12 press laterally against the webs 4, 5 and thus form a stable mechanical connection between the shaft 1 and the webs 4, 5 with the expansion body 10

Claims (6)

fischerwerke Artur Fischer GmbH & Co. KG 72176 Waldachtal M 1783 16 March 1994 Protection claims 1. Fastening element with a fastening head from which a straight shaft projects, which has expansion legs at its free shaft end opposite the fastening head, and which can be driven into a borehole in a masonry, characterized in that the shaft (1) has a short longitudinal slot (9) at its free shaft end (8) which merges into two longitudinal grooves (6, 7) opposite each other on the shaft (1), and that on an expansion body (3) which can be driven into the longitudinal slot (9) there protrude webs (4, 5) which run parallel at a distance from one another and which each lie in one of the two longitudinal grooves (6, 7). 2. Fastening element according to claim 1, characterized in that at least one pre-expansion lock (11, 12) is formed on the shaft (1), against which the expansion body (3) or the webs (4, 5) rest before expansion. 3. Fastening element according to claim 1, characterized in that in the spread position on the shaft (1) clamping elements (11, 12) engage the webs (4, 5) of the expansion body (3). 4. Fastening element according to one of claims 2 or 3, characterized in that notches (11, 12) are formed on the longitudinal grooves (6, 7) as pre-expansion protection and/or as clamping elements. 5. Fastening element according to claim 1, characterized in that the expansion body (3) is an expansion cone tapering in the direction of the fastening head. 6. Fastening element according to claim 1, characterized in that the fastening head is designed as a nail head (2) or as a threaded pin (10).