GB2036230A

GB2036230A - Anchoring fastening elements in holes

Info

Publication number: GB2036230A
Application number: GB7938662A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-11-08
Filing date: 1979-11-08
Publication date: 1980-06-25
Also published as: AU5265179A; IT1166020B; FR2441082A1; BR7907224A; SE7909258L; IT7909591A0

Abstract

A fastening element comprises a bolt (4) threaded at either end, the lower end threadably engaging a stop nut (7) against which an elliptical anchor disk (2) is forced by a sleeve (10) under the influence of a nut threadably engaging the upper end of the bolt, as the element is anchored in position. Anchor disk (2) has a perforation through which the bolt (4) passes. The major diameter of the anchor disk (2) is greater than the diameter of the bore hole such that edges of the anchor disk (2) are urged against and into the bore hole wall as the anchor disk (2) is pressed between the nut (7) and sleeve (10). Various forms of anchor are described. <IMAGE>

Description

SPECIFICATION Fastening and connecting element The invention concerns a fastening and con necting element having the form and action of a dowel to secure the supports provided for a structural part or the like, with the aid of a bore hole in a wall, preferably a hard concrete wall. A variant of the first solution is proposed for use in a soft concrete wall.

Various types of dowels have been known for a long period of time serving as fastening and connecting elements. The known dowels are designed for the most part as expanding dowels and have a great variety of configurations. One of the best known dowels of this type is equipped with freestanding locking wings, which are caused to spread in the bore hole by means of a screw, whereby the wings are pressing against the wall of the bore.

Expanding dowels of this type may be used to mount parts in a great variety of structural materials, both of low compressive strength such as, for example, building boards or aerated concrete and in heavy construction materials, such as for example, in concrete. It is a significant disadvantage of these known dowels that as the result of the spreading inherent in the system, only the outer wing elements engage the wall while the engagement decreases laterally along each wing.

There is, therefore, no fully circular engagement of the anchoring in the wall of the bore, but only an involvement in individual, relatively narrow sectors with respect to the crosssection of the hole. It is readily seen that the permissible tensile stress on expanding dowels of this type is relatively limited. This is a deficiency found in all dowels based on the different expansion systems.

Another disadvantage associated with such dowels is that their pressure on the wall decreases with rising tensile stresses, rather than increasing or at least remaining equal.

A further disadvantage of the known expansion dowels is that the different expansion dowel systems must have relatively large peripheral distances and minimum distances to each other, because of the high pressure exerted by the expansion force on the wall of the bore hole. Still another disadvantage of the known dowels consists of the fact that the different systems must be adapted in their entire form to the prevailing specific conditions. This may begin, for example, with their diameter which must conform in a bore hole to be effective to a relatively narrow range. It is customary to correlate a certain length of the dowel with a given diameter, although even herein, requirements may differ wherein, for example, for a certain dimension of a cross section, different lengths may be needed.A consideration of this one component alone already indicates that when the known expansion dowels are used, the maintenance of large stocks is required.

The inclusion of additional components of this type, such as for example, the materials wherein the bore holes are to be drilled, results in a nearly inestimable multitude of the type of dowel systems to be applied, all of them designed on the expansion system.

BRIEF SUMMARY OF THE INVENTION It is, therefore, the object of the present invention to eliminate the above-described disadvantages and to provide a fastening and connecting element which in the anchored state effects cutting into the wall of the bore nearly on all sides and is capable of anchoring any commercial screw in both hard and soft concrete.

A further object of the invention is to provide an anchoring means which affords a pressure of the anchor against the wall of the bore which rises with increasing tensile stress.

A still further object of the invention consists of providing a fastening and connecting element comprising essentially only commercially available component parts, such as bolts, screws, pins and sleeves and the like, so that stocks and costs may be kept low.

One mode of attaining these objects consists of providing in a fastening and connecting system a disk of an elliptical circumference with a central bore hole, wherein a bolt is inserted with a stop being fastened to the end facing the bottom of the bore hole of said bolt.

The use of a dowel of this type requires that the wall of the bore consist of a relatively hard material, for example, hard concrete because the wall acts upon the elliptical disk so that the latter cuts into the wall on all sides and changes to a nearly round circumference. In softer materials, for example, aerated concrete, the strength of the material is low and the depth of penetration of the elliptical disk must, therefore, be significantly increased.

The latter object is attained by providing in the fastening and connecting element of the above-described type one or more elliptical disks with their edges raised in the manner of a spoon and a longitudinal dimension larger than the diameter of the bore, said elliptical disk or disks being capable of being brought into a position along a guide in the bore, wherein means to transfer and deflect forces to the ridges are effective so that the latter are bent from their oblique position into their anchoring position at right angles or nearly right angles to the wall of the bore and are penetrating predominantly unilaterally, substantially deeper into the wall of the bore hole.

According to the invention, the bolt preferred is in the form of a threaded bolt possibly having threads on both ends, whereby the stop is preferably designed as a nut. These are conventional and commercially available structural elements. If the bore is located in hard concrete, the central bore of the elliptical disk may be round with a diameter large enough to make possible the oblique introduction of the disk along the bolt or the screw, or the central bore of the disk may be an elongated hole or an elliptical hole, wherein the different elliptical axes are in the same direction as the corresponding elliptical axes of the circumference of the disk.

To align and thus anchor the disk with the wall of the bore, a sleeve slid onto the bolt is provided which applies an aligning force to the disk by means of an impact or screw effect so that in the terminal position of the disk its radius is aligned at right angles or nearly right angles to the axis of the bolt or the screw. With the aid of the sleeve placed on the bolt or screw, the necessary force may be transmitted to the disk.

To increase the specific compressive force acting on the wall of the bore, the peripheral area of the disk in its axial direction is made conical so that the effective load per unit area is increased, thus facilitating the penetration of the edge of the disk involved into the wall.

The radius of the minor elliptical circumferential axis of the disk corresponds approximately to the diameter of the bore, while the major elliptical axis of the disk is larger than the diameter of the bore.

According to the invention, it is also possible to apply several disks as anchoring disks to the bore wherein suitable stops in the form of sleeves must be inserted successively between the disks during the application.

For the application of a fastening and connecting element in soft material in the wall of the bore, elliptical disks with edges turned upward in the manner of a spoon are used as described hereinabove. To align and anchor the disk or disks with the wall of the bore, a sleeve to be slid onto the bolt is again provided.

If two disks are to be used to increase the tensile strength, it is necessary to arrange a spacing sleeve between the disks which serves as a sliding surface. It is advantageous to use as the guide for the disk or disks a sleeve insertable in the hole, having an orifice in the lower part of its circumference through which the cutting edge of the disk may be guided to arrive at the wall of the bore hole.

BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention may be seen in the drawing, wherein various embodiments will be explained.

In the drawing: Figure 1 shows a cross section of the fastening and connecting element during its installation into concrete; Figure 2 displays a cross section through the plane of the disk in its final installed condition: Figure 3 represents a cross section through a special form of a disk; Figure 4 shows an arrangement of the fastening and connecting element partially installed and utilizing two disks; Figure 5 displays an embodiment of the fastening element with a lock screw prior to installation; Figure 6 displays an embodiment of Fig. 5 in the installed state; Figure 7 represents a cross section of the fastening and connecting element during installation into a bore hole; Figure 8a is a top view of a disk with edges bent up in the manner of a spoon; Figure 8b is a side elevation of the same disk;; Figure 9 depicts a simplified perspective representation of a sleeve with a disk arranged inside having edges bent up in the manner of a spoon; Figure lOa is a detailed representation of the lower end of a bolt with a stop and a stop of circular shape; Figure lOb is a representation of a stop of a hexagonal shape; Figure 1 Oc represents the form of an external edging of an elongated hole and; Figure ii shows a disk with edged bent up in the manner of a spoon and a recess beginning at the circumference with a minor elliptical radius.

Figure 12 shows a cross section of the fixing and connecting element with a disk which is provided with two spoon-like raised edges, a. during assembly, b. in the anchored state, and Figure 13 shows a cross section through a disk with two spoon-like varied edges.

DETAILED DESCRIPTION OF THE EMBODI MENTS Fig. 1 shows a cross section through a fastening and connecting element located in a bore in concrete prior to its final installation and anchoring.

The bolt 4 is equipped both at its upper and lower end with a threading 8, with a nut screwed onto the lower end 8 facing the bottom of the bore 5. The nut 7 serves as the stop for the disk 2. The disk 2, as seen in Fig.

2 prior to its installed state, has an elliptical circumference wherein the minor radius (r) of the ellipse is approximately of the size of the radius of the bore, while the major radius (R) of the ellipse of the disk is larger than the radius of the bore.

Prior to the installation of the fastening element, the disk 2, because of the major elliptical axis of the disk, occupies an inclined position in the bore. With the aid of the sleeve 10 placed over the bolt, a force is applied to the disk 2 so that the outer edge of the elliptical disk is pressed into the wall of the bore initially at the location of the major axis. The pressure of this force on the disk effects a slight deformation, so that the small radius (r) of the elliptical disk becomes larger and also penetrated into the wall of the bore.

In the final installed state, the disk 2 occupies a horizontal position so that its radii are at right angles to the axis of the bolt or the screw 4. The bottom surface of the disk rests approximately on the top surface of the stop or the nut 7, respectively, and the entire circumference of the disk has penetrated into the wall. Following the establishment of this state, the sleeve 10 may be retracted from the bore or it may remain therein to be fastened by means of the upper nut.

Fig. 3 shows an embodiment of the disk having a conical peripheral area when viewed in section. This has the result that the specific force applied causes the circumference into the wall to be increased.

As mentioned hereinabove, the known expansion dowels have a point of sector shaped contact with the bore with respect to a section through the bore perpendicularly to the axis of the dowel. In contrast, the anchoring surface of the disk according to the invention extends over its entire circumference because during the exposure of the disk to a suitably high tensile force, the disk will position itself at right angles to the direction of tension and the oval disk made of a spring steel will engage the wall of the bore with its major diameter.

Following the erection of the disk which then in the installed condition is arranged approximately at right angles to the bolt, there will be adequate play of the disk in the bore. This play is particularly advantageous especially because readjustment is sometimes necessary in order to fasten a particular element. In the application of bore holes in concrete there is always the danger that the bores are slightly out of alignment. In this case the play of the bolt is highly advantageous so that, during the mounting of an element with several prepared holes, it may be introduced in the prepared holes of a screw plate, even though the bores are slightly off the precise location in the engineering drawings.

When purely tensile forces are needed, the play of the anchor or the bolt is of no importance. If, however, transverse forces are being transmitted, it is necessaryto place a sleeve onto the bolt such as is customary with expansion dowels. With the dowel of the present invention, both tensile and transverse forces may be transmitted wherein in the latter case the bore adapted to the disk which is inserted obliquely is generally lined by the sleeve.

When anchoring heavy loads, it is often necessary to introduce very large forces into deep bore holes. In such cases, it is possible according to the invention to provide a plurality of disks 2 over each other. In Fig. 4 two disks 2 are shown with a spacing sleeve 1 7 between them. The disks are introduced successively and anchored in the bore 6 with the wall 9 with the aid of the sleeve 10.

Another embodiment is shown in Figs. 5 and 6, wherein in place of the bolt 4, a lock nut is used. The lock nut has above its head a rectangular extension 14. The rectangular extension 14 is adapted to the elongated hole of the disk 2 so that the lock nut 1 3 is secured against rotation in the installed state.

It is further of advantage to press a thin disk 1 5 over the disk 2, the thin disk being pressed against the rectangular extension 14 by the sleeve 10 during the tightening of the thread 8. As the result, the lock nut is fastened to the anchored disk 2, so that the lock nut with its rectangular extension 14 cannot slip from the elongated hole, should the bore be deeper than the height of the rectangular extension 14. This insures that the nut cannot fall into a deeper hole and thus be prevented from turning. It also insures that it is still capable of being moved in the bore hole when the sleeve is removed therefrom.

Fig. 7 shows a section through a fastening and connecting element located in a bore in soft concrete prior to the final installation or anchoring, respectively. The bolt 104 is equipped on its upper and lower ends with threads 11 7, 108, respectively, with a nut screwed onto the lower thread 108 facing the bottom of the bore 105, said nut serving as the stop for the disk 2. The disk 102, shown in more detail in Fig. 8a, has edges 11 2 bent upward in the manner of a spoon on its lateral parts and at its end 111. As may be seen in particular in Fig. 8b, the disk is of a conical shape.

During the introduction of the disks 102 into the bore 106, they are in an inclined position so that the cutting edge 11 9 of the disk 2 is pointing downwards, while the opposing spoon shaped end 111 of the disk 102 is parallel to the wall of the bore during the insertion. During the insertion of the bolt 104 into the bore 106, the disks 102 are maintained in their inclined position with the aid of a shrinking foil, not shown, so that the cutting edges 11 9 slide along the wall 109 of the bore into their final position.In this final position, the bottom side of a disk 102 abuts either against the top side of the stop 107 or against the top side of the spacing sleeve 11 8, so that the cutting edge 11 9 of the disk 102 cuts into the wall 109 of the bore while the flat edged end 111 of the disks pre-ses against the wall 109 of the bore, thus generating a force component favoring the process of cutting into the wall of the disks 1 02. With the positioning of the disks 102 at right angles, the spoon shaped edging rolls on the wall of the bore and cuts into it in its final position.

In this embodiment, it is predominantly the cutting edge 11 9 that cuts into the wall 109 of the bore. It may, therefore, be of advantage to arrange several disks over each other, wherein the disks as viewed in the projection form a right angle. In this manner, an adequate number of cutting edges 11 9 of the disks 102 may be inserted in the wall 109 of the bore, so that there is a sufficient force countering the tensile stress on the bolt 1 04.

The number of disks is preferably determined by the strength of the wall 109 of the bore.

To obtain a symmetry of the anchoring surfaces with respect to the circumference of the bore 109, it is advantageous to have a slide edge follow the cutting edge 11 9. The spoon like edging and the beadings 112, respectively, in the area of the elongated hole 103 substantially increases the strength of the disk in relation to buckling. The width of the disk or the distance of the edges 11 2 from each other is chosen so that it is either slightly larger or approximately equal to the diameter of a spacing sleeve 118.

Fig. 9 shows a further embodiment of the invention in a simplified perspective representation of a sleeve 1 24 with a disk or a web 102. The web 102 is designed in a manner similar to the embodiment according to Fig. 7 i.e., it is equipped with a cutting edge 11 9 and a sliding edge 111 in the shape of a spoon.

Prior to installation, the disk 102 having a longitudinal dimension longer than the diameter of the bore is in an inclined position within the sleeve 1 24 and is impacted with the aid of a cylindrical rod 125, for example, a mandrel, into a right angle position whereby it penetrates into the wall of the bore and occupies a position at right angles to the axis of the sleeve. This provides for the secure anchoring of the sleeve 1 24 in the bore.To effect the anchoring of the disk 102 or to its turning into the vertical position, respectively, the inner wall of the sleeve 1 24 may be provided with an internal thread which is engaged by the external thread of a cylinder, not shown, so that during the downward rotation of said cylinder a force is applied to the disk 102, whereby the latter is turned into the right angle position. This internal thread of the sleeve 1 24 may also be used to screw in an extension piece following the anchoring of the sleeve, for example, a hook or the like.

As seen in Fig. 10, the bolt 104 may be in the rectangular or hexagonal form or it may be designed in the shape of an elongated hole. The diameter of the bolt is then slightly smaller than the width of the elongated hole 103 of the disk 102 so that each disk may be moved on the bolt in the axial direction, while secure against rotation.

When using a cylindrical bolt 104, an extension 104 is located above the stop 107 which may be designed rectangular, hexagonal or even in the shape of an elongated hole, wherein dimensioning is such that the disk 102 with its elongated hole is held secure against rotation by its extension 114.

In Fig. 11, a disk or a web with a spoon like edging or a beading 111 may be seen, wherein a recess 1 28 originating at the circumference with the minor radius of the ellipse, is provided. Two such disks may be inserted into each other with their recesses and inserted with the aid of a sleeve 1 24 into the bore. The cutting edges of the two disk are opposing each other so that they cut virtually over the entire circumference of a bore.

Fig. 1 2a shows a fixing element in a drilled hole, consisting of a bolt 1 30 with a lower nut 1 31 and an upper screwable nut 1 32 and a washer 1 33 which covers the drilled hole 1 34. The disk 1 35 used here, which is shown in detail in Fig.13, has two spoon-like raised edges which stand opposite one another and are formed facing in opposite directions. Fig.

1 2a shows the disk 1 35 provided with two spoon-like raised edges before the anchoring process.

Fig. 1 2b shows the same fixing element after anchoring. This is carried out by tightening nut 1 32 so that the bolt 1 30 with its lower nut 131 is drawn upwards. In the process a pressure is exerted by lower nut 131 and sleeve 136 on disk 135 so as to swing the disk 1 35 through approximately 90 and cause it to penetrate the wall of the drilled hole.

This type of fixture is particularly suitable for expanded concrete.

The present invention achieves a nearly complete abutting of the disks on all sides, with the disks acting as anchors and, even in cases wherein the disks had not attained their final horizontal position, there is an increase in the pressing force with rising tensile stresses.

This is the decisive advantage over all of the known dowels, because with the present invention, it is possible to stress the anchor to the yield strength of its material.

Another advantage of the invention consists of the fact that after the disk or disks have attained their transverse position in the bore, they cannot be moved from their final position. The bolt, on the other hand, is inserted loosely in the hole of the disk, so that, for example, it may be lowered in the case of a suitably deep bore when the lower stop is in the form of a nut and secured by means of cams on the bottom surface of the disk or extensions of the nut in the elongated hole of the disk against rotation.

It may occur during the insertion of dowels that the latter must be installed in the area of a wall edge, for example, a girder (beam).

When dowels known heretofore are used, it is necessary to maintain a given distance from the edge of the wall. This is related to the fact that known dowel systems exercise a spread action on the wall of the bore, which is transmitted to certain areas of the wall. If the limiting distance specified is not observed, the dowels may not be fully loaded.

With the present invention, however, a much smaller distance from the edge may be applied because there is no spreading action on the bore walls but, as described hereina bove, a cutting into the wall of the bore takes place. The edge distance to be observed is also valid for the distance of the fastening elements between themselves so that the present invention affords an abbreviated distance of the fastening elements, so that full loading is possible.

Claims

1. Fastening and connecting element having the shape and effect of a dowel for the securing into the intended position of a structural part or the like, with the aid of a bore hole in a wall, preferably a hard concrete wall, characterized by that a disk having an elliptical circumference is equipped with a center hole for a bolt to be inserted through said center hole, said bolt having a stop fastened to its end facing the bottom of the bore hole.

2. Fastening element according to Claim 1, characterized by that a conventional threaded bolt with a head serving as the stop is used as the bolt with the top.

3. Fastening element according to Claims 1 or 2, characterized by that a center hole of the disk is in the form of an ellipse or an elongated hole.

4. Fastening element according to Claim 1 or one of the preceding claims, characterized by that a sleeve placed onto the bolt or the screw is provided for the alignment and anchoring of the disk with and in the wall of the bore, said sleeve applying an aligning force by means of an impact or screw effect to the disk, so that in the final position of the disk its radius is directed at right angles or nearly right angles with respect to the axis of the bolt.

5. Fastening element according to Claim 1 or one of the preceding claims, characterized by that the radius of the minor axis of the elliptical disk is approximately equal to the radius of the bore hole and that the major radius of the elliptical disk is larger than the radius of the bore hole.

6. Fastening element according to Claim 1 or one of the preceding claims, characterized by that in place of the bolt or the screw a lock screw is used, said screw being secured against rotation by its rectangular extension in the elongated hole of the disk, wherein onto the shaft of the lock screw a thin disk is pressed above the disk, said thin disk being pressured to the rectangular extension.

7. Fastening element according to Claim 1 or one of the preceding claims, characterized by that a plurality of disk with a spacing sleeve arranged between each pair of the disks.

8. Fastening and connecting element having the shape and effect of a dowel to secure the intended position of a structural part or the like with the aid of a bore hole in a wall, preferably a soft concrete wall, characterized by that one or a plurality of elliptical disks with spoon like edging and a longitudinal dimension greater than the diameter of the bore hole, is capable of being inserted in the bore hole along a guide in a position wherein means for the transfer of forces and the deflection of forces are acting on the disks, so that said disks arrive from their inclined position in their anchoring position directed at right angles or nearly right angles to the wall of the bore hole.

9. Fastening and connection element according to Claim 8, characterized by that a bolt equipped at one of its ends with a stop is inserted through the elongated hole of at least one disk, wherein a sleeve may be placed upon the rod for the alignment with an anchoring to the wall of the bore hole of the disk or disk.

1 0. Fastening or connecting element according to Claims 8 or 9, characterized by that the bolt has an extension above the stop said extension being in the shape of a rectangle or a hexagon, or of the circumference of an elongated hole.

11. Fastening and connecting element according to Claims 8, 9 or 10, characterized by that between two disks a spacing sleeve is arranged.

1 2. Fastening and connecting element according to Claims 8 to 11, characterized by that a plurality of disks arranged above each other with their longitudinal axes, as viewed in projection, form an angle to each other, preferably a right angle.

1 3. Fastening and connecting element according to Claim 1, characterized by that a sleeve which may be inserted in the bore hole is provided for the guidance of the disk said sleeve having in the lower part of its circumference an orifice through which the cutting edge of the elliptical disk may be guided, in order to penetrate the wall of the bore hole.

1 4. Fastening and connecting element according to Claims 8 through 13, characterized by that the disk is provided with a spoon like edging inclined at an angle of approximately 45 and having a sharp edge at its upper border, said edge penetrating into the wall of the bore hole upon attaining the final position of the disk at right angles.

1 5. Fastening and connecting element according to Claims 1 3 or 14, characterized by that the sleeve has an internal thread which is engaged by the external thread of a cylindrical rod.

1 6. A fastening and connecting element substantially as herein before described with reference to the accompanying drawings.