Expansible anchor plug

© Holder (s):

© Mandatairefs): Cabinet Nony.

(54) Expansion plug with retractable expansion body.

(57) Expansion plug consisting of an expandable sleeve 1 and an expansion body 2 of spherical shape allowing a deviation of the threaded bolt 3 relative to the axis of the expandable sleeve 1. Between the expansion body 2 and the expandable sleeve 1, there exists before the start of the spacing operation a connection of the stop notch type. Thus, the expandable sleeve 1 and the expansion body 2 can be assembled beforehand in a s ingle unit.

FR 2 552 829 - A1

<img file="FR2552829A1_D0001.tif" />

D

Sale of booklets at IMPRIMERIE NATIONALE, 27. rue de la Convention - 75732 PARIS CEDEX 15

EXPANSION ANKLE WITH RETRACTABLE EXPANSION BODY

The present invention relates to an expansion plug comprising an expandable bushing whose expansion zone has longitudinal slots as well as a recess widening towards the front end in the driving direction, and an expansion body provided with '' a thread and can be retracted into the expandable bushing by means of a threaded bolt with radial enlargement of the expansion zone.

Expansion dowels of the type mentioned above have considerable advantages such as ease of assembly and post-expansion behavior.

If necessary, such dowels can most often be re-loosened and removed.

In practice, it relatively often happens that the surface of the building element to be fixed is not absolutely perpendicular to the axis of the receivi ng hole made for the expansion plug in the receiving material. This can be due, on the one hand, to the fact that the base surface and the rear surface of the element to be fixed are not parallel, as is the case, for example, for a profiled beam. On the other hand, it is possible that when the receiving hole is produced, there is a deviation from the axis perpendicular to the surface of the receiving material. If in such a case, in order to produce a prestress, a torque is applied to the threaded bolt, there is a bending load on the rod of this threaded bolt due to the unilateral application of the head of said threaded bolt .

Therefore, it is possible that in an extreme case, the head is completely or partially torn off from the rod of the threaded bolt.

An inclined position of the threaded bolt can also occur due to non-conformity of the axial distances on the construction element to be fixed and on the receiving material. In the event that an element of

255282Ç construction has more than two fixing points, even the realization of elongated holes is useless, because these holes can only compensate for nonconformities in one direction.

The drawbacks mentioned above cannot be avoided by means of a known expansion plug, the expansion body of which has the shape of a cylinder, the axis of which is perpendicular to the longitudinal axis of the plug. This anchor intended mainly for anchoring in light materials such as gas-concrete and the like has an expandable sleeve made up of two branches which can be separated from one another by the expansion body, and created by penetrating the inside the receiving material a mechanical connection by correspondence of shapes. The threaded bolt connected to the expansion body can, inside the expandable sleeve, deviate from the longitudinal axis in only one plane.

The present invention aims to provide an expansion plug which allows universal adaptation to non-flatness of the surface of the receiving material or the building element to be fixed.

According to the present invention, this object is achieved by the fact that the expansion body has a substantially spherical shape. Due to the spherical conformation of the expansion body, a spherical articulation is created inside the expansion plug. This spherical joint allows tilting on all sides of the threaded bolt around the center of the expansion body.

In specific cases, it is possible to introduce the expansion plug, in the pre-assembled state, consisting of an expandable sleeve and an expansion body, into the receiving material, passing through the element. of construction to be fixed. This mounting method requires the presence in the building element to be fixed of a

2552822 through hole whose diameter is at least equal to the outside diameter of the expandable bushing. Since this is often impossible, for example for reasons of solidity, it is necessary to screw the threaded bolt into the expansion plug previously introduced into the drilling hole. To facilitate this. operation, it is advisable that the expansion body has, for its alignment, on its outer side, a peripheral annular bead placed in a plane perpendicular to the axis of the tapping, bead which serves as a stop and cooperates with the side front of the expandable sleeve. Instead of the cooperation on the front side, it is also possible to provide a special stop for the annular bead on the expandable sleeve.

To further facilitate the alignment of the two threads when screwing the threaded bolt into the expansion body, it is advantageous that the rear end of the tapping of the expansion body is provided with a chamfer. This chamfer allows centering and alignment of the expansion body on the threaded bolt. The opening angle of this chamfer is preferably between 60 and 90 degrees.

To avoid, when handling the expansion plug, an exit from the expansion body of the expandable sleeve, a separable connection can be provided, for example by gluing, soldering or welding. Such a bond can be particularly strong and require considerable forces to be removed before the expansion operation begins. A connection avoiding these drawbacks is obtained if, in accordance with another characteristic of the invention, the expandable bushing present on the front end of the recess area widening, a projection serving as security for the expansion body. This projection can for example have the shape of a continuous peripheral bead or the shape of one or more bosses. Between the expansion body and the expandable sleeve, there is thus formed a sort of connection by stopper. If necessary, this connection can be easily removed and the expansion body can be replaced by another.

The invention is explained below using the appended drawing giving an example of embodiment. On this drawing :

FIG. 1 represents an expansion plug according t o the present invention, in the unexpanded state, partially in section;

2 shows a front view of the expansion plug shown in Figure 1, according to arrow A; and Figure 3 shows the expansion plug of Figures 1 and 2 in the anchored state.

The expansion plug shown in FIGS. 1 to 3, is constituted by an expandable socket designated as a whole by 1 and an expansion body connected to this socket generally designated by 2. The socket has an expansion zone 1b following the front end la in the driving direction. The expansion zone 1b is provided with longitudinal slots starting from the front end 1a, as well as a recess 1d widening towards the front end 1a.

The longitudinal slots allow it to radially widen the expansion zone 1b. The expansion body has a substantially spherical shape and is provided with a through thread 2a. The expansion body 2 further has on its outer side a peripheral bead 2b extending unwinding in a plane perpendicular to the axis of the setting 2a. This bead 2b limits the possible rotation of the expansion body 2 relative to the sleeve 1. The front end of the sleeve 1 then serves as a stop for the bead 2b. The rear end of the thread 2a of the expansion body 2 is provided with a chamfer 2c. The chamfer 2c is used to center or facilitate the screwing of a threaded bolt designated as a whole by 3 in the expansion body 2. To prevent the expansion body 2 from leaving the recess ld widening in the direction from the front end 1a, the sleeve 1 is provided at its front end with a projection. Between the expansion body 2 and the sleeve 1, a connection is formed by a catch.

As shown in Figure 2, three longitudinal slots are regularly distributed around the periphery of the sleeve 1. This arrangement of the longitudinal slots is however given only by way of example, and it is also possible to provide slots longitudinal in greater or lesser number.

In Figure 3, the dowel object of the present invention is placed in a blind hole 4a of a receiving material designated as a whole by 4. By means of the threaded bolt 3, a building element 5 is tightened against the material of receiving 4. The building element 5 has a surface inclined towards the surface of the receiving material. The threaded bolt 3 has on its rear side a hexagon head 3a and a rod 3b following it, the front part of which is provided with a thread 3c. The threaded bolt 3 is screwed, passing through an interposing washer 6, the construction element 5 and the expandable bush 1, in the expansion body 2. By applying a torque to the hexagon head 3a, the expansion body 2 is retracted into the sleeve 1, widening the expansion zone 1b. Due to the spherical conformation of the expansion body 2, a kind of spherical joint is created between the sleeve 1 and the expansion body 2, which allows an inclined position of the threaded bolt 3 relative to the axis of the sleeve 1. The deflection angle of the threaded bolt 3 then depends on the length as well as the internal diameter of the expandable sleeve 1. The expansion plug according to the present invention can · if necessary be loosened again, after having partially detached the threaded bolt 3, by applying blows against the hexagonal head 3a and being withdrawn from the blind hole 4a.

The expansion plug according to the present invention is preferably made of metal. However, for low loads it is possible to manufacture the expansion body 2 and / or the expandable sleeve 1 from plastic.

Ί