Abstract:
The invention relates to a reinforcement device for fastening, in this context, tremendous loads to particularly weaker walls of the type wallboard coated stud frame, and to contribute to the ability of walls to resist horizontal forces. The reinforcement device comprises portions, which connect and reinforce the parts of the wall construction. Thus, exceeding a materials tensile strength can be avoided, and the forces are distributed over a larger area, wherein the resistibility thereof can be summarised to a larger resistance. In a certain embodiment the reinforcement device can be used for fastening in solid constructions, such as light concrete and hollow brick constructions.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    The present invention relates to a device for fastening details to walls and/or reinforcement of walls comprising wallboards, for example of gypsum, mounted to a framework, wherein the supporting parts may be studs of, for example, wood or metal. The device is to be positioned in the areas of the wallboard absent of framework parts.  
           [0002]    When the device is provided with a cavity filling effect the indentation of the wallboards is reduced under the influence of stress.  
           [0003]    For example, such an ability is required for backings to be tiled or otherwise coated with rigid materials which may crack and break, or when a rigid construction is required or desired.  
         STATE OF THE ART  
         [0004]    The traditional method to perform fastening to wallboards of, for example, gypsum, may be to introduce plugs of plastic or rubber into predrilled apertures in the wallboard. These plugs are wedged when expanding and are forced against the edges of the wallboard in the aperture, for example when a screw having a larger diameter than the aperture usually provided in the plug is introduced therein. So called hollow wall screw anchors are also present, which are Introduced into a small aperture and expands on the rear side of the wallboard.  
           [0005]    Screws having an elongated screw nut profile are also present. The screw nut profile may be positioned parallel to the screw and, when brought through the wallboard, extended perpendicular to the screw to receive support from the rear side of the wallboard. In one embodiment the invention can be limited to a similar range of application, which is indicated essentially with reference to FIGS. 20, 21,  22 ,  23 .  
           [0006]    One major drawback with the devices according to prior art is that they do not tolerate large forces before the material of the wallboard is breaking, because of the use of only one part of the wall.  
           [0007]    When more rigid walls are required than normally the studs are arranged closer. Usually this imply a distance between the studs of 40 cm. To reinforce present walls removal of one wallboard is required for opening the wall to enable the introduction of more studs, which then are coated with a wallboard of normal quality. Alternatively more rigid special wallboards present on the market are selected. Then, the original distance between the studs can be used, which usually is 60 cm. Also in this case one wallboard is removed. Yet another manner is to provide the wall with an additional standard wallboard. This imply that, for example, the length of a bathroom wall usually is reduced by two times the thickness of a wallboard, which in a normal case results in two times 13 mm, i.e. 26 mm. This might cause a problem with the dimensions of the interior equipment, such as the dimensions of a bathtub to be reinstalled and consequently is not fitting in its earlier position. Yet a more extensive drawback is in this case that present water conduit connections may be found inside the wall, wherein a water leakage is undetectable, and if a leakage arise the water is forced into the wall by the impermeable layer on the surface of, for example, sanitary walls. All cases also require a large amount of work and materials and are consequently expensive. Usually, the costs for electricity and conduit installations increase if the number of studs and wallboard layers are altered in present walls.  
         SUMMARY OF THE INVENTION  
         [0008]    One object of the present invention is to enable larger loads on fastening means than possible with present devices, and to enable reinforcement of the wallboards of a wall. The reinforcement device may be used for fastening exclusively or reinforcement exclusively or in combination, for example, when particularly large stress is to be managed.  
           [0009]    The present invention uses the fact that, for example, a wall of gypsum wallboard mounted on a framework of studs comprises one wallboard on each side of a stud. The reinforcement device is in its most simple embodiment a cylinder adapted to reach through one of the wallboards from its outer side and through the space between the wallboards, which space is a result of the stud, to the inner side of the opposite wallboard. In this position the cylinder may be fastened by the means of a glued joint. Thus, a fastening means is obtained having a lever substantially increasing its ability to bear loads mounted to the free end thereof. If the direction of the forces is increased towards a vertical direction the importance of the lever-forming design of the cylinder is increasing, especially when mounted in a substantially vertical construction. The ability of the cylinder to handle forces is limited by the strength of the glued joint at the opposite wallboard and the size of the contact surface of the lead through of the front wallboard. When loaded until collapse the glued joint is breaking and/or the material at the inlet of the wallboard is crushed. The distance between the wallboards can also be of importance.  
           [0010]    The lever is increased with the distance, which results in a more extensive resistance. The cylinder must be rigid to avoid bending thereof.  
           [0011]    Further, the cylinder may be hollow in its length and provided with holes through the portion of the surface thereof, positioned in the space of the wall.  
           [0012]    For example, an elastic fabric or film may further be positioned around the cylinder, which functions as a mould for expanding substances injected into the cylinder upon requirement. These force their way out through the holes and fill the mould surrounding the cylinder, wherein a rigid body casting the cylinder and sticking to and filling between the wallboards is obtained. This results in a reinforcement device increasing the rigidity of the wall and to which, for example, screws or hooks can be mounted and then loaded with extensive loads.  
           [0013]    By increasing the area glued to the opposite wallboard and the radius of the reinforcement device at the lead through of the wallboard, the performance is increased accordingly.  
           [0014]    According to one embodiment the device may be regarded as a cylinder with a first and a last portion having a somewhat larger diameter than the intermediate portion. This design is used to enable for the wire cloth to be winded up on the intermediate portion, wherein the wire cloth can be brought through the aperture arranged in the outer wallboard in the mounting procedure. The performance is increased with increasing end diameters of the cylinder. The glued end of the cylinder, may in every embodiment be bordered for improved adherence.  
           [0015]    If the wall is filled with a medium, for example present types of sufficiently stabile insulation, the cylinder does not have to be surrounded by the wire cloth. Instead a space of desired dimensions can be formed in the current medium, which space is adapted for the current design of the reinforcement device.  
           [0016]    According to one embodiment an elongated plate is mounted in the end of the cylinder, which is to be glued to the opposite wallboard. By this manner the largest possible surface can be brought through the substantially circular aperture.  
           [0017]    According to another embodiment a further elongated plate is enclosed, which is unattached and thread onto the cylinder shaft. This plate can then be pulled towards the back side of the first wallboard and glued thereto. This will increase the strength of the wallboard and, thus, the loading capacity.  
           [0018]    When an elongated plate is used the plates can either be positioned opposite each other, or with 180 degrees of displacement, and then be turned to an optional position in a full circle of 360 degrees as a combined unit, dependent on the direction and size of the current forces and how these, in each case, are handled in the best manner according to calculation.  
           [0019]    In several of the different embodiments the reinforcement device can be provided with the wire cloth, and thereby with reinforcing fillings between the wallboards.  
           [0020]    According to one embodiment, where improvement of the wall to carry horizontal pressure is desired but filling of the space between the wallboards with more than the cylinder not is desired, the portion of the cylinder not glued to the rear wallboard and the aperture through the wallboard may be formed somewhat conical. The gap formed thereby may then be filled with a hardening joint sealing compound. This construction transfers horizontal forces applied to the front wallboard also to the rear wallboard. The extracting resistance of the reinforcement device in a horizontal direction is also improved.  
           [0021]    All cylinder tubes of fastening devices adapted for injection may be provided with an adapter unit between the internal cylinder area and a hole adapted for a screw after injection of, for example, an expanding substance.  
           [0022]    The device may in some embodiments, especially as a straight cylinder ( 12 ) and ( 15 ) or having a reel shape ( 18 ), also be applied in solid materials, such as light concrete or hollow bricks.  
           [0023]    The devices are then glued to the surrounding material in the entire length of the device, or a desired and possible portion thereof.  
           [0024]    According to one embodiment one construction part may be excluded, for example a cylinder, which enable fastening to the rear wallboard. Instead a more traditional reinforcement of the front wallboard may be used.  
           [0025]    To facilitate the mounting of the device, particularly at the hardening of glues or joint compounds if used, a fixing device associated to the device may be used. This comprises of a substantially circular cone having a peg, which can be inserted in the aperture  16 .  
           [0026]    The cone is provided with a larger diameter than the device so that it is supported by surrounding surfaces, to which it temporarily can be fastened by the means of glue and/or a pin.  
           [0027]    It may also be provided with filling spacers to compensate for differences in diameter. Such a spacer may also be mounted permanently.  
           [0028]    If there is space filling means, for example mineral wool insulation in the wall, and removal of this is desired a space clearing tool developed for the device may be used. The tool comprises a bar having a pivoted front portion provided with a cutter. This tool is inserted through an aperture in the wallboard and is heavily rotated, for example by the means of a drilling machine. The pivoted portion is extended and clears a space having a radius corresponding to the length of the pivoted portion and a space length corresponding to how far the tool is inserted. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    The drawings are labelled: Fig . . . , and a number, and shall be read in the order stated. The numerical order may be reversed.  
         [0030]    The invention will now be described in more detail with reference to the accompanying drawings, in which  
         [0031]    [0031]FIG. 1 is a schematic side view in longitudinal section of the device according to one embodiment as a straight cylinder mounted in a wallboard coated timber frame wall.  
         [0032]    [0032]FIG. 1F (F refer to a front view=the outside of a wall) illustrates the device from the front.  
         [0033]    [0033]FIG. 2 is a longitudinal section view from above of the device in FIG. 1.  
         [0034]    [0034]FIG. 3 is a schematic side view in longitudinal section of the device according to one embodiment as a straight cylinder and provided with a joint lead through of the wallboard.  
         [0035]    [0035]FIG. 3F illustrates the device in FIG. 3 from the front.  
         [0036]    [0036]FIG. 4 is illustrates the device in FIG. 3 from above.  
         [0037]    [0037]FIG. 5 is a schematic side view in longitudinal section of the device according to one embodiment as a straight cylinder, having a conical end portion, mounted in a wallboard coated stud frame wall.  
         [0038]    [0038]FIG. 5F illustrates the device in FIG. 5 from the front.  
         [0039]    [0039]FIG. 6 is a longitudinal section view from above of the device in FIG. 5.  
         [0040]    [0040]FIG. 7 is a schematic side view in longitudinal section of the device according to one embodiment similar to a reel.  
         [0041]    [0041]FIG. 7F illustrates the device in FIG. 7 from the front.  
         [0042]    [0042]FIG. 8 illustrates the device in FIG. 7 from above.  
         [0043]    [0043]FIG. 10 is a schematic side view in longitudinal section of the device according to an embodiment similar to FIG. 7, but joint compound has been applied, for example an expanding substance.  
         [0044]    [0044]FIG. 9F illustrates the device in FIG. 9 from the front.  
         [0045]    [0045]FIG. 9 illustrates the device in FIG. 10 from above.  
         [0046]    [0046]FIG. 15 and FIG. 16 is a schematic side view in longitudinal section of the device according to one embodiment, in which the rear portion of the device is elongated and as large as possible for insertion through the aperture of the front wallboard. The movable part, which is similar to the rear portion and can be pulled along the cylinder to the rear side of the front wallboard, is also illustrated. Further, the cylinder body and the portion filling the lead through in the wallboard is illustrated.  
         [0047]    [0047]FIG. 15F illustrates the device in FIG. 15 and FIG. 16 from the front.  
         [0048]    [0048]FIGS. 11 and 12 illustrates the device in FIG. 15 and FIG. 16 from above.  
         [0049]    [0049]FIG. 18 illustrates the same device as in FIG. 15 and FIG. 16 provided with  27  and injected with  26 .  
         [0050]    [0050]FIG. 18F illustrates the device in FIG. 15 and FIG. 16 from the front.  
         [0051]    [0051]FIG. 14 illustrates the device in FIG. 15 and FIG. 16 from above.  
         [0052]    [0052]FIG. 13 is a schematic view from above illustrating the conversion of FIG. 15 to FIG. 17.  
         [0053]    [0053]FIG. 17F illustrates FIG. 17 from the front.  
         [0054]    [0054]FIG. 19 illustrates the device in FIG. 17 from the side and provided with  27 ,  26 .  
         [0055]    [0055]FIG. 19F illustrates FIG. 19 from the front.  
         [0056]    [0056]FIG. 20 is a schematic side view of the device illustrated without the cylinder and having one plate pulled towards  30 . This design of the device reinforces and fastens in one wallboard only, namely the one closest to the fastening means.  
         [0057]    [0057]FIG. 21 illustrates the device in FIG. 20 from the side in a contracted position.  
         [0058]    [0058]FIG. 22 illustrates the device in FIG. 20 from the front.  
         [0059]    [0059]FIG. 23 illustrates the device in FIG. 21 from above. 
     
    
     DESCRIPTION  
       [0060]    With reference to FIG. 1 the reinforcement device is illustrated as a straight and possibly solid cylinder body  12  arranged between wallboards  10 . This design is adapted to be utilized for the fastening of fastening means, such as screws, to fasten loads acting in a substantially perpendicular direction in relation to the longitudinal section. The cylinder body  12  comprises an aperture  16  for fastening means, which aperture  16  is arranged along the centre of the cylinder body  12 . The cylinder body further comprises a bordered end  13 , a fixing pin  22  to protrude into a rear wallboard  10 , which fixing pin  22  is projecting from one end of the cylinder body  12 , and a glued joint  14 . An area of a wallboard lead through  15 , or envelope surface of the cylinder body  12 , is illustrated in FIG. 1. FIG. 1F illustrates the device from the front, i.e. from the outside of the construction, which normally is a wall. FIG. 2 illustrates the device from above, wherein a stud  11  also is indicated.  
         [0061]    An aperture is arranged in the front wallboard  10 , wherein the cylinder body  12  provided with the glued joint  14  can be introduced and fastened to the rear wallboard  10 .  
         [0062]    With reference to FIG. 3 the reinforcement device is illustrated as a cylinder body  12  provided with a glued joint  14  at one portion of the cylinder body  12  to be positioned at the front wallboard  10 . This design is adapted for utilization in connection with the fastening of fastening means, such as screws, to fasten loads acting in a substantially perpendicular direction in relation to the longitudinal section. However, the glued joint  14  contributes to a certain extent to the distribution of horizontal forces acting upon the wallboard, and to increase the extraction resistance of the reinforcement device in a horizontal plane. For example, the cylinder body  12  comprises a bordered cylinder surface  24  at the wallboard lead through area  15 . FIG. 3F illustrates the device from the front, i.e. from the outside of the construction, which usually is a wall. FIG. 4 illustrates the device from above. An aperture is arranged in the front wallboard, wherein the cylinder body  12  provided with the glued joint  14  can be inserted and fastened to the rear wallboard and the lead through.  
         [0063]    With reference to FIG. 5 the reinforcement device is illustrated as a cylinder body  35  having a conical end portion. When a tapered lead through  36  and the glued joint  14  is arranged, this embodiment is adapted to be used for the fastening of fastening means, such as screws, to fasten loads acting in a substantially perpendicular direction in relation to the longitudinal section. However, the glued joint contributes to the distribution of horizontal forces acting upon the wallboard, and increases the extraction resistance of the reinforcement device in a horizontal plane. FIG. 5F illustrates the device from the front, i.e. from the outside of the construction, which usually is a wall. FIG. 6 illustrates the device from above.  
         [0064]    The mounting is performed as in FIG. 3, with the addition of the tapered aperture  36  and that the cylinder body  12  is changed to cylinder body  35 .  
         [0065]    With reference to FIG. 7 the reinforcement device is illustrated as a reel-shaped hollow cylinder body  18 . The reel-shape is used when a thinner intermediate portion is desired. When the rear bordered portion  20  of the reel-shaped cylinder and the wallboard lead through area  15  is formed with a larger surface, this embodiment for the fastening of fastening means, such as screws, to fasten loads acting in a substantially perpendicular direction in relation to the longitudinal section, will carry larger loads. A glued joint  25  between a front portion  23  of the reel-shaped cylinder  18  and the front wallboard  10  contributes to the distribution of horizontal forces acting upon the wallboard and the extraction resistance of the reinforcement device in a horizontal plane will increase by using a larger bordered rear portion  20 . When a reel-shaped hollow cylinder body  18  is used, this may be provided with a reduction plug  21  having an aperture for fastening means. For example, the cylinder body  18  comprise holes  19 . FIG. 7F illustrates the device from the front, i.e. from the outside of the construction, which construction usually is a wall. FIG. 8 illustrates the device from above.  
         [0066]    The mounting is performed as in FIG. 3, but the straight cylinder body  12  is changed to a reel-shaped cylinder body  18  and the glued joint  14  is changed to the glued joint  25 .  
         [0067]    With reference to FIG. 10 the reinforcement device is illustrated as a reel-shaped cylinder body  18 . The reel-shape is used when a thinner intermediate portion is desired. An elastic wire cloth  27 , or another suitable medium, can be applied to this intermediate portion when an expanding joint compound  26  is intended to be used. After the wire cloth  27 , which can be compared to a portion of a very elastic stocking, is thread onto the thinner intermediate portion of the cylinder body, the cloth is glued at the, points  29  with, for example, a fast hardening glue of a conventional hot-melt type of glue. This is performed to enable filling of the mould with joint compound, such as polyurethane foam, and preventing it from flowing out thereof. When the rear bordered portion  20  of the reel-shaped cylinder and the wallboard lead through area  15  is formed with a larger surface, this embodiment for the fastening of fastening means, such as screws, to fasten loads acting in a substantially perpendicular direction in relation to the longitudinal section, will carry larger loads. A glued joint  25  and the joint compound  26  contributes to the distribution of horizontal forces acting upon the wallboard and the extraction resistance of the reinforcement device in a horizontal plane will increase by using a larger  20  and the joint compound  26 . When  18  is used, this may be provided with a reduction plug  21 . FIG. 9F illustrates the device from the front, i.e. from the outside of the construction, which usually is a wall. FIG. 9 illustrates the device from above when applying the joint compound  26  by the means of a nozzle  28 . Mounting procedure: An aperture adapted for the cylinder body  18  is arranged in the front wallboard. The diameter of the aperture shall correspond to the front portion  23  and the rear portion  20  of the reel-shaped cylinder. Glue or joint compound for the joints  14  and  25  is applied. A wire cloth  27  is thread onto the intermediate portion of the cylinder. The cylinder body is brought into the aperture of the front wallboard and is glued to the rear wallboard. The cylinder and the mould is filled with, for example, polyurethane foam  26 .  
         [0068]    With reference to FIG. 15 and FIG. 16 the reinforcement device is illustrated in a side view of the device according to one embodiment, in which the rear portion of the device is elongated and as large as possible to be brought through the insertion aperture in the front wallboard  10 . Further, the movable part is illustrated, which is similar to the rear portion, and can be pulled along the cylinder to the rear side of the front wallboard. Further, the cylinder body and the portion filling the wallboard lead through is illustrated. The cylinder body  32 , having its front portion  30  and its rear portion  31 , forms a rigidly assembled unit. In FIG. 15 the front portion  30  is connected with the front wallboard  10  by the means of the glued joint  25  and the rear portion  31  is connected with the rear wallboard  10  by the means of the glued joint  14 . The tapered sides of the front portion  30  provides a supporting part, particularly when a movable part  34  is pulled against the rear side of the front wallboard. The remaining sides of the front portion  30  are not tapered. This is due to that these surfaces are expected to substantially distribute forces perpendicular to  15 . Thus, horizontal forces acting to move the fastening device are avoided. The elliptic shape of a rear cylinder portion  31  and the movable part  34  contributes to give maximum surface to those portions which are to be brought through the aperture in the front wallboard. In turn this results in maximum reinforcement and fastening capacities. The size of  30  is also important for these capacities. Further, pull-strings  33  are arranged on each side of the cylinder, wherein the movable part  34  rotates when the pull-strings are winded around the cylinder and  34  is pulled along the cylinder to its front position against  30 . FIG. 16 illustrates the movable part  34  connected with the front wallboard  10  by the means of the glued joint  14 .  
         [0069]    [0069]FIG. 15F illustrates the device in FIG. 15 and FIG. 16 from the front.  
         [0070]    [0070]FIG. 11 and FIG. 12 illustrates the device in FIG. 15 and FIG. 16 from above.  
         [0071]    Mounting procedure: The combined unit  30 , 32 , 31 , having the movable part  34  arranged adjacent to the rear portion  31 , is inserted into the aperture adapted to the front portion  30 . The aperture adapted to  30  may, for example, be arranged with a conventional hole cutter and tapered by the means of a file to fit the elliptic shape of  30 . The elongated plates  31  and  34  are held in a parallel position and are inserted into the aperture with the portion extending the most from the central axis of the cylinder first. The rear portion  31  is already provided with glue and is glued to the rear gypsum wallboard, and in occurring cases to the glued joint  25  on the portion  30 , and on the part  34  glued to the rear side of the front wallboard. This latter glue is also gluing the front portion  30  to the movable part  34 . The combined unit described above is pressed against the rear gypsum wallboard and is fastened thereto by the means of the fixing pin  22 . As a result the movable part  34  can be pulled into position by the means of the pull-strings  33 , see FIG. 16. Locking means can now be threaded onto the pull-strings, which may be permanent or in position only until the joints are hardened. If a hollow cylinder body is used the holes thereof can, if required, be reduced by the means of an adapter  21 . If filling with joint compound  26  is intended as is illustrated in FIG. 18, this is injected before sealing with  21  takes place.  
         [0072]    [0072]FIG. 18 illustrates the same device as in FIG. 15 and FIG. 16 but provided with the elastic wire cloth  27  and injected with joint compound.  
         [0073]    This increase the capacity of the reinforcement device to give, for example, a wall increased ability to bear larger horizontal and vertical forces in the area affected by forces, which in turn acts upon the fastening means.  
         [0074]    [0074]FIG. 18F illustrates the device in FIG. 18 from the front.  
         [0075]    [0075]FIG. 14 illustrates the device from above.  
         [0076]    Mounting procedure: The same as described with reference to FIGS. 15 and 16 with the addition that the wire cloth  27  is threaded before the parts  34  and  31  are brought together. Fastening of the wire cloth to the mentioned parts is also required, suitably by a conventional fast hardening hot-melt, to be stretched when  34  is pulled into position against the rear side of the front wallboard. See FIGS. 18, 18F and  14 .  
         [0077]    [0077]FIG. 13 illustrates how the reinforcement device has been mounted according to FIG. 17, wherein the unattached part  34  has been brought to rotate 180 degrees. The instructions of FIGS. 15 and 16 is followed, but with the difference that the pull-strings  33  are winded half way around the cylinder body. When  34  is pulled into position against the rear side of the front wallboard,  34  rotates a half turn.  
         [0078]    [0078]FIG. 19 illustrates a case when the injection of joint compound  26  Is continued. This must be prepared by the mounting of wire cloth  27  before  34  is brought together with  31 , before the insertion through the aperture arranged in the front wallboard. Since  34  will rotate a half turn  31  and  34  must be kept in this final position when the wire cloth is fastened, suitably with a fast hardening hot-melt. Suitable fastening points are:  
         [0079]    See FIGS. 19 and 19F.  
         [0080]    1. fold the wire cloth and fasten it to  34 , close to the cylinder body but not against it.  
         [0081]    2. fold the wire cloth and fasten it to  31 , one fastening point, at the rounded end, close to the cylinder body.  
         [0082]    3. pull the wire cloth over the corners of  31  and fasten it thereto.  
         [0083]    The wire cloth is now fastened in four points and is resting upon the cylinder body when the reinforcement device is mounted to the wall, and can receive polyurethane foam for example.  
         [0084]    With reference to FIG. 20 the reinforcement device is illustrated without the cylindrical intermediate portion. The rear wallboard is rectangular, or substantially rectangular. An aperture having a suitable size, adapted for fastening fastening means  37  and the plate  38 , is arranged in the front wallboard. The device can be turned in an optional direction in a full circle of 380 degrees. The edges of the aperture is tapered to fit to  30 , or alternatively an unattached front portion. The plate  38  is provided with glue and connected with  30 , which can be provided with glue  25 , through the pull-strings  33 . The plate is brought into the aperture, which among other things is possible by the length and flexibility of the pull-strings. The unattached portion  30  is inserted into the aperture and is filling it up. The plate  38  is pulled together with  30  and the rear side of the front wallboard, and can be fastened thereto by the means of locking means threaded onto the pull-strings. Except FIG. 20, illustrating the reinforcement device in this form from the side when positioning  30 , having its elliptic front with the larger diameter, horizontally, FIG. 21 illustrates the device from the side when it is pulled together and otherwise positioned as illustrated in FIG. 20. FIG. 22 illustrates the device positioned as described in FIG. 20 from the front. FIG. 23 illustrates the device positioned as in FIG. 20 from above.  
         [0085]    If space filling means, such as mineral wool insulation, is present in the wall and the removal of this is desired a space clearing tool developed for the device may be used. The tool comprises a bar having a pivoted front portion provided with a cutter. This tool is inserted through an aperture in the wallboard and is heavily rotated, for example by the means of a drilling machine. The pivoted portion is extended and clears a space having a radius corresponding to the length of the pivoted portion and a space length corresponding to how far the tool is inserted.  
         [0086]    To facilitate the mounting of the device, particularly at the hardening of glues and joint compounds, a fixing device associated to the device may be used. This comprise of a substantially circular cone having a peg, which can be inserted in the aperture  16 .  
         [0087]    The cone is provided with a larger diameter than the device so that it is supported by surrounding surfaces to which it temporarily can be fastened by the means of glue and/or a pin. It may also be provided with filling spacers to compensate for differences in diameter. Such a spacer may also be mounted permanently.  
         [0088]    The device can in some of the embodiments, particularly as a straight cylinder  12  and  35  or having a somewhat reel-shape  18 , also be applied to solid materials, such as light concrete or hollow bricks. The devices are then glued to the surrounding material in the entire length of the device, or a desired and possible portion thereof.