Abstract:
Cage nut for installation in an elongate, preferably rectangular opening which is only accessible from one side, comprising a nut body with a cylindrical internal thread carrier having an internal thread and an abutment part attached thereto, and a cage encompassing the nut body, wherein the abutment part is adapted to the shape of the opening and has a slightly smaller width and a slightly shorter length than the opening, although the length of the abutment part is significantly greater than the width of the opening; the cage is configured resiliently and is adapted to the shape of the opening such that it can be clipped into the opening and the cage supports stop elements which only allow a rotation of the abutment part with respect to the cage in the screwing-in direction of the internal thread from an installation position parallel to the longitudinal direction of the cage into a retaining position approximately perpendicular thereto.

Description:
TECHNICAL FIELD 
     The present invention relates to a cage nut for installation in an elongate, preferably rectangular opening which is only accessible from one side, comprising a nut body with a cylindrical internal thread carrier having an internal thread and an abutment part attached thereto and a cage which encompasses the nut body. 
     BACKGROUND 
     For so-called “blind applications”, i.e. for applications in which the installation point can only be accessed from one side, such as large metal sheets, special section tubes, bodywork parts or similar sheet metal parts, so-called “blind rivet nuts” have hitherto been used to introduce a nut thread into parts of this type. These blind rivet nuts (also denoted by BRN) are seated using a specific processing tool, in that by squeezing the blind rivet nuts, a so-called “closing head” is produced which fixes the nut. Since the corresponding blind rivet nuts per se and particularly also the closing head which has formed are relatively weak, in the past it has only been possible to use blind rivet nuts to attach light or ancillary components. The “high-strength blind rivet nut” developed by the company Avdel was the first blind rivet nut to also allow structural connections having relatively high pre-tensioning forces, due to the relatively high thread strength of said nut. 
     Even in the case of these high-strength blind rivet nuts, the problem arose relatively quickly that bolts with a strength of 10.9 or above, which are to be screwed as far as the yield point, generate such high pre-tensioning forces that the closing head starts to sink or starts to deform during the bolt installation. In the worst case, this would result in the closing head shearing off, i.e. the blind rivet nut would be destroyed and would then have to be replaced. In any case, the subsequent sinking/deformation would result in a significantly lower pre-tensioning force, compared to the presets given by the defined torque and angle of rotation bolting procedure. The additional angle of rotation caused a sinking/deformation of the BRN instead of the desired increase in pre-tensioning force. Due to this sinking or deformation, the industry routinely experiences problems in achieving the defined bolting curves even with high-strength blind rivet nuts and thus in monitoring the correct assembly of tie bars on vehicles, for example. 
     Another possibility known from the prior art of providing sheet metal parts with internal threads is the use of so-called cage nuts. However, to install cage nuts, in the prior art it was necessary for either the rear side of the part to also be accessible or additional auxiliary holes were required to introduce the cage nut from the side, as is necessary for so-called “C-clips” of the prior art. A cage nut of this type, configured as a clip, is disclosed, for example in EP 703 021 B1 which would appear to be the closest prior art in respect of the present invention. 
     BRIEF SUMMARY 
     It is therefore the object of the present invention to make it possible to introduce an internal thread into an opening, which is accessible from only one side, in a sheet metal component, without requiring additional auxiliary openings (as is the case for C-clips), and without the pre-tensioning force restrictions of the prior art blind rivet nuts. 
     The object of the present invention is achieved by a cage nut which is capable of being installed in an elongate opening which is only accessible from one side, in that this cage nut has an abutment part which is adapted to the shape of the opening and has a slightly smaller width and a shorter length than the opening, although the length of the abutment part is significantly greater than the width of the opening, the cage being of a resilient configuration and being adapted to the shape of the opening such that it can be clipped into the opening, and the cage supports stop elements which only allow a rotation of the abutment part with respect to the cage in the screwing-in direction of the internal thread from an installation position parallel to the longitudinal direction of the cage into a retaining position approximately perpendicular thereto. 
     In this respect, the stop elements are preferably configured such that they hold the nut body in a floating manner in the cage in the installation position. This measure ensures that the nut body is retained securely in the installation position even during transportation and during processing and also during the clipping-in procedure. 
     It is also preferred to provide the internal thread with a thread securing means (clamping means) in the region remote from the screwing-in side. This ensures that the nut body is rotated in any case in good time out of the installation position into the retaining position before the end of the screwing-in procedure, since the clamping means forces an adequate transfer of torque between the bolt and the nut body which causes the rotation of the nut body by 90°. 
     It is further preferred that the cage is configured such that it exerts a spring force on the nut body towards the opening. In this way, the nut body is held even more securely in the installation position, thereby ruling out an accidental premature rotation during transportation or during the clipping in procedure. 
     A particularly preferred configuration is provided when an annular abutment surface for spring elements of the cage is arranged on the nut body, and when this abutment surface is provided with cams or with an undulating profile such that the cams or the elevated portions of the undulating profile engage with the spring elements of the cage precisely when the nut body leaves its floating installation position in the cage. This can ensure that the nut body locks securely into the retaining position from the installation position. 
     A further particularly preferred construction is provided when the stop elements rest on an annular abutment which is arranged in the nut body coaxially to the internal thread on the side facing the opening, and when this abutment has recesses for receiving the stop elements, which recesses are arranged such that, in the retaining position, the stop elements are accommodated therein. This measure prevents the nut body from being able to be rotated again into a new installation position beyond the retaining position during installation. 
     In this respect, it is particularly preferred when the transition from the abutment into the recesses in the direction of rotation is configured as a bevel. This measure ensures a smooth transition into the retaining position and allows different sheet thicknesses to be compensated. 
     It is further preferred that the transition from the recesses into the abutment is configured as a stop surface which extends parallel to the axis of rotation of the internal thread. This measure can reliably rule out an “over rotation” of the nut body again into an installation position. 
     A further embodiment of the present invention which is particularly simple to produce is provided when positioned on the blind side of the cage, onto the cylindrical internal thread carrier, is a plastics material part which has a central opening and also has resilient arms which extend beyond a blind-side surface of the cage level with the abutment part and hold said abutment part in a floating manner in the installation position. 
     In this respect, it is particularly preferred when the plastics material part is provided with a collar which extends in the direction of the blind side and concentrically encloses the cylindrical internal thread carrier. 
     Finally, it is particularly preferred when the dimensions of the blind-side surface of the cage and of the plastics material part are similar to those of the abutment part and when the arms are respectively arranged diagonally in the vicinity of the corners of the plastics material part in the screwing-in direction of the internal thread, while the stop elements are in each case arranged opposite the arms. 
     In the following, the present invention will be described in more detail on the basis of the embodiments illustrated in the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a cage nut according to the invention introduced into an opening in a metal sheet and already being in the retaining position; 
         FIG. 2  is a sectional view of the cage nut, according to the invention, of  FIG. 1 , in the installation position cut parallel to the axis of rotation of the internal thread; 
         FIG. 3  shows the cage nut, according to the invention, of  FIG. 1  in the installation position; 
         FIG. 4  shows different modified embodiments of the cage nut according to the invention; 
         FIG. 5  is a three-dimensional view of an embodiment of a cage nut according to the invention; 
         FIG. 6  is a sectional view through the axis of rotation of the internal thread and parallel to the long edges of the nut body of  FIG. 5 ; 
         FIG. 7  shows the embodiment of  FIG. 5  from above; 
         FIG. 8  is a sectional view of the embodiment of  FIG. 5 , cut through the axis of rotation of the internal thread and parallel to the short edges of the nut body; 
         FIG. 9  is a three-dimensional view of the cage belonging to the nut body shown in  FIG. 5 ; 
         FIG. 10  is a sectional view through the cage of  FIG. 9 , viewed from the long side; 
         FIG. 11  shows the cage of  FIG. 9 , viewed from the short side; 
         FIG. 12  shows the cage of  FIG. 9  from above; 
         FIG. 13  is a three-dimensional view obliquely from above in the installation position of the cage nut assembled from the parts according to  FIGS. 9 and 5 ; 
         FIG. 14  shows the assembled cage nut of  FIG. 13 , viewed from the long side; 
         FIG. 15  shows the assembled cage nut of  FIG. 13 , viewed from above; 
         FIG. 16  shows the assembled cage nut of  FIG. 13 , viewed from the short side; 
         FIG. 17  is a spatial view of a further particularly preferred embodiment of the cage nut according to the invention in the installation position; 
         FIG. 18  is a spatial exploded view of the cage nut of  FIG. 17  from below; 
         FIG. 19  is a spatial exploded view of the cage nut of  FIG. 17  obliquely from above; 
         FIG. 20  shows the cage nut of  FIG. 17  in the installation position from below; 
         FIG. 21  shows the cage nut of  FIG. 17  in the installation position from the side, cut partially along the axis of rotation of the internal thread; 
         FIG. 22  shows the cage nut of  FIG. 17  in the installation position from above; 
         FIG. 23  shows the cage nut of  FIG. 17  from the side, fitted into a suitable opening; and 
         FIG. 24  shows the cage nut of  FIG. 17  fitted into a suitable opening, in the installed position, viewed from the blind side. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a cage nut  10  according to the invention which, in this case, has already been inserted into an opening  12  in a metal sheet  14 , and is already in the retaining position. For reasons of clarity, the corresponding bolt which is screwed into the nut is not shown. 
     The illustrated cage nut  10  according to the invention comprises a nut body  16  which is surrounded by a cage  18 . The nut body  16  comprises a cylindrical internal thread carrier  20  with an internal thread  22  and an abutment part  24  which is in the form of an elongate rectangle beveled at the corners and which develops out of the sheet-side end of the internal thread carrier  20 . The cage  18  consists of a thin sheet of spring steel and has an elongate rectangular base plate  26 , the shape of the base plate  26  approximately corresponding to the shape of the abutment part  24  and the dimensions of the opening  12  being selected to be slightly greater than the dimensions of the abutment part  24  or of the base plate  26 . 
     Two bent-up resilient arms  28  adjoin in each case in the centre of the two short sides of the base plate  26 . In this respect, the arms  28  are initially bent obliquely outwards away from the sheet  14  and are then bent slightly obliquely inwards away from the sheet  14 . The arms  28  partly engage over the internal thread carrier  20  level with the end, remote from the sheet  14 , of the internal thread carrier  20 . 
     At its end remote from the sheet  14 , the internal thread carrier  20  has an annular abutment surface  30  which is respectively provided, in the areas in which it comes closest to a side of the abutment part  24 , with cams  32  which arch upwards. In this respect, the arms  28  of the cage  18  are provided with corresponding bulges  34  so that they can lock with the cams  32 . The cams  32  are thus arranged in a spacing of 90° in each case. Therefore, two opposite cams  32  are covered in each case by the arms  28  both in the installation position and in the retaining position. 
       FIG. 2  is a sectional view of the cage nut  10 , according to the invention, of  FIG. 1  in the installation position and along the axis of rotation of the internal thread  22 , viewed from the side of the sheet. This figure clearly shows the opening  36  for the passage of a fitting bolt, which opening is arranged in the base plate  26  of the cage  18 . Formed opposite the points of origin of the arms  28 , on the edge of the opening  36  are stop elements  38  which are bent vertically upwards away from the sheet side, starting from the base plate  26  of the cage  18 . In the installation position shown here, i.e. if the longitudinal directions of the base plate  26  of the cage  18  and of the abutment element  24  of the nut body  16  correspond, the stop elements  38  run on an annular guide path  40  which extends coaxially around the internal thread  22  at the sheet-side end of the internal thread  22 . Relative to the sheet-side surface  42  of the abutment part  24 , this guide path is arranged offset away from the plane of the sheet  14 . The guide path  40  is provided with two recesses  44  which receive the stop elements  38  when the cage nut  10  is in the retaining position. Here, only one recess  44  is shown because of the sectional illustration. The further recess which is not shown is formed point-symmetrically to the axis of rotation of the internal thread  22 . 
     The transition from the guide path  40  into the recess  44  is configured as a bevel  46 , thereby allowing a sliding transition from the installation position into the retaining position of the nut  10 . The transition from the recess  44  back into the guide path  40  is configured as a stop surface  48  which runs parallel to the axis of rotation of the internal thread  22 . This reliably prevents an “over rotation” of the nut body  16  out of the retaining position back into the installation position. Furthermore, the stop surface  48  can be configured such that it interrupts the entire guide path and extends as far as the sheet-side surface  42  of the abutment part  24 . This measure can prevent the cage nut  10  according to the invention from being turned against the screwing-in direction into the retaining position from the installation position during transportation or installation before it has even been installed. 
       FIG. 3  shows the cage nut  10  according to the invention, again from the viewing direction of  FIG. 1 , but in the installation position. Therefore, a comparison of  FIGS. 1 and 3  allows a detailed description of the installation and bolting procedures. 
     The cage nut  10  is delivered in the installed state shown in  FIG. 3 . In this state, the longitudinal sides of abutment part  24  and of base plate  26  of the cage  18  are arranged parallel to one another. As a result, the nut body is held in a floating manner above the base plate  26  by the stop elements  38 . The small cams  32  shown in  FIG. 1  on the annular abutment surface  30  are located under the corresponding recesses  34  in the resilient arms  28 . As a result, the nut body  16  is held to some extent in an anti-rotation manner in this position, so that accidental turning of the nut body  16  relative to the cage  18  during transportation or installation is substantially avoided. 
       FIG. 2  clearly shows how, in this position, the nut body  16  is held in a floating manner against the spring force of the resilient arms  28  of the cage  18  by the stop elements  38  which are supported on the guide path  40 , i.e. there is a defined distance between the base plate  26  of the cage  18  and the sheet-side surface  42  of the abutment part  24  of the nut body  16 . 
     In this state, the cage nut  10  according to the invention is clipped into a suitable opening  12 , for example in a metal sheet  14 . The spring force of the cage  18  holds the cage nut  10  in the opening  12 . 
     A bolt can then be screwed into the internal thread  22 . To ensure a reliable change-over from the installation position into the retaining position of the nut, the internal thread  22  is provided with a thread securing means (clamping means) in the region remote from the screwing-in side. 
     To ensure that the nut body  16  is also secured in the retaining position, the enlarged retaining cams  32 ′ which can be clearly seen in  FIG. 3  are also provided. These retaining cams  32 ′ are configured such that they also ensure adequate spring pre-tension by the resilient arms  28  of the cage  18  on the nut body  16  when the nut body has been moved towards the sheet  14  after the stop elements  38  have sunk into the recesses  44 . These enlarged cams  32 ′ also ensure that the nut body  16  cannot be rotated again beyond the retaining position into a new installation position, because the tracking of the spring pre-tension ensures that the stop elements  38  rest securely against the stop surface  48 . 
       FIG. 4  shows further possibilities of configurations according to the invention of the resilient arms  28  of the cage  18 . As already shown in  FIG. 1-3 , these arms  28  can either engage on the end, remote from the sheet  14 , of the internal thread carrier  20 , in which case the respective engagement surfaces  30   b ,  30   c  can either be smooth or can be configured with an undercut  50  to secure the resilient arms  28 . 
     An alternative construction provides the support of the spring arms  28  on the retaining part  24  of the nut body  16 . In this case as well, an undercut  52  can be provided to secure the resilient arms  28  more effectively. 
     The following  FIGS. 5 to 16  show an embodiment of a cage nut according to the invention in detailed workshop drawings. 
     In this respect, identical reference numerals relate to identical elements, as stated above. 
       FIG. 5  is a three-dimensional spatial view of the corresponding nut body  16 , and here the crosswise arrangement of the cams  32  and  32 ′ and the different sizes thereof can be seen very clearly. 
       FIG. 6  is a sectional view of the nut body of  FIG. 5 , cut parallel to the long side of the nut body  16  through the axis of rotation of the internal thread  22 . 
     Here, the recess  44  for locking the stop elements  38  in the retaining position can be seen particularly clearly. 
       FIG. 7  shows the nut body  16  of  FIG. 5  from above. This figure also very clearly shows the crosswise arrangement and the different sizes of the cams  32  and  32 ′. 
       FIG. 8  is a sectional view of the nut body  16  of  FIG. 5 , cut parallel to the short side of the nut body  16  through the axis of rotation of the internal thread  22 . 
       FIG. 9  is a three-dimensional view of a cage  18  which matches the embodiment of the nut body according to  FIG. 5 . This figure particularly clearly shows the configuration of the resilient arms  28  with the recesses  34  for locking the retaining cams  32 ,  32 ′ and the formation of the stop elements  38 . 
       FIG. 10  shows the cage of  FIG. 9 , viewed from the long side. 
       FIG. 11  shows the cage  18  of  FIG. 5 , viewed from the short side. 
       FIG. 12  shows the cage  18  of  FIG. 9  from above. 
       FIG. 13  is a three-dimensional view, obliquely from above and in the installation position, of the assembly of the nut body  16  with the cage  18  to produce the cage nut  10  according to the invention, i.e. in the form in which the cage nut  10  according to the invention is delivered and is inserted into a corresponding recess in a metal sheet. 
       FIG. 14  shows the cage nut  10  according to the invention, assembled and in the installation position, viewed from the long side, and this figure shows particularly clearly how the nut body  16  is held in a “floating” manner between the stop elements  38  and the relatively small cams  32  which are locked into the recesses  34  in the resilient arms  28 . The substantially larger configuration of the enlarged cam  32 ′ can also be seen here very clearly. 
       FIG. 15  shows the cage nut  10  according to the invention in the assembled state and in the installation position, viewed from above. This figure also clearly shows the configuration and arrangement of the cams  32 ,  32 ′. 
       FIG. 16  shows the assembled cage nut  10  according to the invention, viewed from the short side, also in the installation position. 
     The present invention provides for the first time a cage nut specifically for unilateral access. Unlike cage nuts of the prior art, the cage nut according to the invention can be directly inserted into a rectangular hole in a metal sheet or in a tubular profile. No auxiliary holes are required for inserting the cage at the side, as is necessary in the case of so-called C-clips of the prior art. According to the invention, for the first time, the cage  18  is itself clipped directly into the hole and is fixed automatically by an undercut in the cage. The nut body  16  rests on two stop elements  38  which develop out of the base plate  26  of the cage  18 . The two resilient arms  28  have two functions: firstly, to generate a spring effect/pretension to allow the cage  18  to be clipped into the rectangular hole  12  in the metal sheet  14  and secondly, to hold down/press down the nut body  16  with a spring force, so that the nut body  16  rests on the stop elements  38 , even when an appropriate counter force is generated by the inserting/impressing of a bolt for the bolting down procedure. 
     The internal thread  22  of the nut body  16  is advantageously provided with a thread securing means (clamping means) in the region remote from the metal sheet, up to which securing means the bolt can be screwed in from the lower side without relatively great resistance. As soon as the bolt runs against the clamping means, the nut body  16  rotates relative to the cage  18  and to the metal sheet  14 . Since the nut body  16  only sits on the two stop elements  38 , configured as sheet metal lugs, of the cage  18 , the nut body can be easily rotated. After a rotation by 90°, the two stop elements  38  lock into the rectangular recess  44  under the internal thread  22 . As soon as the stop elements  38  lock into the recess  44 , the spring force of the resilient arms  28  presses the nut body  16  down onto the sheet  14 . At the same time, further rotation of the nut body  16  is stopped, because the stop elements  38  in the recess  44  run against the edge  48  and become locked there or further rotation is blocked by this edge  48 . To ensure that even when the nut body  16  sinks, sufficient spring force from the resilient arms  28  of the cage  18  still acts on the nut body  16 , said nut body  16  can have in the upper region a type of cam  32 ′ which compensates the height difference during the sinking onto the sheet. After the nut body  16  has been blocked on the stop elements  38 , the bolt can then be screwed in against the clamping/securing means until the set tightening moment is reached. Since the abutment part  24  has a contact surface which is great enough such that the maximum surface pressure of the sheet  14 , which can be made of aluminium, for example, is not exceeded, the cage nut according to the invention functions as a standard nut-bolt connection, but with the advantage of a simple clip-in installation, also with only unilateral access. 
       FIGS. 17 to 24  show an embodiment of the cage nut  110  according to the invention which can be produced in a particularly economical manner. 
       FIG. 17  shows this cage nut  110  obliquely from above, in other words, viewed from the blind side. This embodiment of the cage nut also has a nut body  116  which is enclosed by a cage  118 . In this case as well, the nut body  116  comprises a cylindrical internal thread carrier  120  with an internal thread  122  and an abutment part  124  which is in the form of an elongate rectangle rounded off at the corners, and which develops out of the workpiece-side end of the internal thread carrier  120 . The cage  118  consists of a thin sheet of spring steel and has an elongate rectangular base plate  126 , the shape of the base plate  126  approximately corresponding to the shape of the abutment part  124 . Adjoining the two narrow sides of the rectangular base plate  126  are curved resilient elements  127  which extend in a direction away from the blind side, have a slight offset  129  and an end stop  131 , using which elements  127  the cage  118  can be clipped into a suitable opening of a corresponding size in a workpiece. 
     Furthermore, attached to the longitudinal sides of the base plate  126  is a respective stop element  138  which also extends away from the blind side. In this respect, the two stop elements  138  are attached diagonally opposite one another and against the diagonal in which the nut body  116  would move when a bolt is screwed into the internal thread  122 . In the present case, the embodiment is illustrated for a right-handed thread as the internal thread  122 , and the embodiment would be mirror-inverted for a left-handed thread. 
     The function of the stop elements  138  is to prevent the nut body  116  from being able to rotate in the wrong direction, for example when a bolt is to be unscrewed again, and to serve as stop elements in the screwing-in direction, and thus the nut body  116  abuts against these stop elements  138  at approximately 90° with respect to the installation position when a bolt is screwed in and thus remains in position. 
     In this embodiment as well, the design engineer faces the problem that the nut body must be held in a “floating” manner above the plane of the workpiece in the installation position. In this embodiment, this is achieved by a plastics material part  160  which is also rectangular and approximately has the dimensions of the abutment part  124  or of the base plate  126  of the cage  118 , although it can be shorter in the longitudinal direction. This plastics material part  160  is positioned directly onto the blind-side surface of the base plate  126 . To make this possible, it has a passage opening, through which the internal thread carrier  120  passes. To improve the mounting of the plastics material part  160  on the internal thread carrier  120 , it is possible for a collar  164 , arranged coaxially to the internal thread carrier  120 , on the plastics material part  160  to extend in the direction of the blind side, as shown here. The plastics material part  160  can be attached to the internal thread carrier  120  either by an interference fit (provided by the resilience of the plastics material of the plastics material part  160 ) of the internal thread on the passage opening  162  or additionally on the collar  164 . 
     Shown here is a reinforced attachment by pressing, and it is possible to see the corresponding deformations  166  on the internal thread carrier  120 , which rule out the possibility of the plastics material part  160  sliding off the internal thread carrier  120 . To be able to hold the nut body  116 , the plastics material part  160  is provided with arms  168  which are resilient and completely encompass the base plate  126  and partly encompass the abutment part  124 . To improve the elastic deformability of the arms  168 , said arms can be partly separated from the plastics material part  160  by means of a wedge-shaped notch  170 . Furthermore, a recess  172  for each of the arms  168  can be provided in the base plate  126 . 
     As shown here, the resilient elements  127  on each of the longitudinal sides of the base plate  126  can merely be formed in the vicinity of the corners of the base plate  126  and can be separated by a recess  133 , depending on the size of the corresponding cage nut and on the desired spring force for the clipping-in procedure, although a continuous metal sheet can also be used which extends over the entire narrow side without a recess. 
     The configuration of the individual constituents of plastics material part  160 , cage  118  and nut body  116  becomes even clearer in the exploded drawings of  FIGS. 18 and 19 .  FIG. 18  shows the exploded drawing obliquely from below, i.e. viewed from the screwing-in side. Viewed upwards from the bottommost drawing, the nut body  116  with the internal thread  122  and the internal thread carrier  120  can be clearly seen. From the side shown here, after installation, an appropriate bolt can be screwed into the internal thread  122 . In the embodiment illustrated here, this figure shows very clearly how not only the edges of the base plate  124  are rounded off but also, to achieve an improved utilisation of space in the cage  118 , how the narrow sides of the rectangular abutment part  124  are rounded off in the form of a circular arc. The next illustration upwards is of the cage  118  and in this figure, the recesses  172  for the arms  168  and the passage opening  174  through the base plate  126  of the cage  118  are very clearly visible. In an installed state, the internal thread carrier  120  extends with a corresponding clearance through the circular opening  174 . 
     Shown further up is the plastics material part  160 , the opening  162  for receiving the internal thread carrier  120  and the arms  168  with the wedge-shaped recesses  170 , arranged next to them, being particularly clearly visible here. 
       FIG. 19  shows the same exploded view, but here it is obliquely from above, in other words, viewed obliquely from the blind side. This figure also shows upwards from below: nut body  116 , cage  118  and plastics material part  160 . The opening  174  in the base plate  126  of the cage  118  for the passage of the internal thread carrier  120  and also the recess  172  for the arms  168  of the plastics material part  160  can also be seen particularly clearly here. In the illustration of the plastics material part  160 , only one of the arms  168  with the wedge-shaped recess  170  and the collar  164  can be seen. The rounding, in the shape of a circular arc, of the narrow sides of the abutment part  124  of the nut body  116  can also be clearly seen here. 
       FIG. 20  shows the preferred embodiment of the cage nut  110 , viewed from the screwing-in side. This figure also clearly shows the rounding, in the shape of a circular arc, of the narrow sides of the abutment part  124  of the nut body  116 . 
       FIG. 21  shows the further embodiment of the cage nut  110  according to the invention from the side and partially cut along the axis of rotation of the internal thread  122 . This figure shows particularly clearly how the base plate  126  of the cage  118  is received between the plastics material part  160  and the abutment part  124  of the nut body  116 , while the collar  164  of the plastics material part  160  forms an interference fit with the internal thread carrier  120 . 
       FIG. 22  shows the further embodiment of the cage nut  110  according to the invention from the blind side. This figure shows particularly clearly the arms  168  and the recesses thereof  170 . 
     Finally,  FIG. 23  shows how the further embodiment of the cage nut  110  is inserted into a corresponding opening  112  in a workpiece  114 . This figure shows particularly clearly how the stop ends  131  of the clips  127  come into contact with the workpiece, while the undercut  129  of the clips  127  hold the cage nut  110  in a defined position. The figure also clearly shows here how the abutment part  124  is held by the arms  168  and the stops  138  such that it floats above the plane of the workpiece  114 . 
       FIG. 24  shows the illustration of  FIG. 23  from the blind side. This figure particularly clearly shows the opening  112 , to be provided for the installation of the cage nut  110 , in the workpiece  114 . 
     Starting from the installed state shown in  FIGS. 23 and 24 , the following takes place when a bolt is screwed into the internal thread  122 : 
     As a result of the bolting procedure, on the one hand the nut body  116  is drawn onto the plane of the workpiece  114  and on the other, is subjected to a torque. As a result, the arms  168  draw aside, the nut body rotates by 90° in the screwing-in direction until it contacts with its longitudinal side the narrow edge of the stop elements  138 . The nut body  116  is then located in the retaining position in which it rests with a large part of its base area on the workpiece  114  outside the opening  112 , and thus forms a reliable abutment for the bolting procedure, with which abutment an excessively high load by the workpiece  114  is avoided, since an adequate surface is available to divert the forces. 
     A release of the bolting is again easily possible, because then, as soon as the bolting forces cease, the nut body is rotated back into the installation position until it comes into contact again with the broadsides of the stop elements  138 , as a result of which the cage nut is again located in the installation position. The arms  168  can snap in again and the nut could even be removed from the opening again by compressing the clip  127 . 
     Therefore, the present invention affords the following advantages: 
     The cage nut  10 ; 110  according to the invention can be clipped directly into a punched, rectangular hole. No tools or aids are required for this installation and the cage nut can also be easily installed using only one hand. Unlike a “C-clip” nut when introduced through the auxiliary hole, the cage nut according to the invention cannot fall on the blind side and thus “disappear”. 
     The cage nut  10 ; 110  according to the invention can be used for different sheet metal thicknesses by an appropriate configuration of the cage  18 ; 118 . Furthermore, there is a smooth contact surface for the component to be installed, and not a curved surface, as in the case of the “C-clip” nut. This produces a reduced sinking of the connection. 
     The cage nut  10 ; 110  according to the invention is advantageously bolted automatically by the insertion and screwing in of the bolt. 
     Finally, in the present invention, the contact surface of the abutment part  24 ; 124  can be configured to be large enough so that sheets of light metal (for example aluminium) also withstand the surface pressure when a bolt is installed beyond the elastic limit.