Abstract:
In order to improve a securing nut comprising a base member which is provided around its circumference with a key face contour, a threaded bolt receptacle which is provided with an internal thread and passes through the base member in the direction of a central axis as well as at least one clamping element which is provided on the base member, in such a manner that it is, on the one hand, simple to produce and, on the other hand, allows reliable clamping without damaging the threaded bolt it is suggested that the clamping element be a collar which is arranged on one side of the base member and in which the internal thread is continued, and that the collar extend around the threaded bolt receptacle in an essentially closed manner in circumferential direction with respect to the central axis.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     The present disclosure relates to the subject matter disclosed in German application number 10 2009 004 638.0 of Jan. 9, 2009, which is incorporated herein by reference in its entirety and for all purposes. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a securing nut comprising a base member which is provided around its circumference with a key face contour, a threaded bolt receptacle which passes through the base member in the direction of a central axis and is provided with an internal thread as well as at least one clamping element arranged on the base member. 
     Securing nuts of this type are known, wherein in their case the clamping element is formed from individual separate projections which can lead to the formation of chippings at the threaded bolt when the securing nuts are screwed on. 
     The object underlying the invention is, therefore, to improve a securing nut of the generic type in such a manner that it is, on the one hand, simple to produce and, on the other hand, allows reliable clamping without damaging the threaded bolt. 
     SUMMARY OF THE INVENTION 
     This object is accomplished in accordance with the invention, in a securing nut of the type described at the outset, in that the clamping element is a collar which is arranged on one side of the base member and in which the internal thread is continued, and that the collar extends around the threaded bolt receptacle in an essentially closed manner in circumferential direction with respect to the central axis. 
     The advantage of the solution according to the invention is, therefore, to be seen in the fact that as a result of the essentially closed course of the collar around the threaded bolt receptacle the collar has, on the one hand, a greater stability than the individual projections known from the state of the art and that, in addition, it is possible to prevent ends of the projections resulting in damage to the threaded bolt, in particular, in the formation of chippings at the threaded bolt. 
     In principle, it would be possible for the collar to be provided with openings. 
     It is, however, particularly advantageous when the collar extends around the threaded bolt receptacle in a completely closed manner. 
     The advantage of this solution is to be seen in the fact that it is particularly stable and has no tendency whatsoever to form chippings. 
     With respect to the design of the collar, no further details have so far been given. 
     One advantageous solution, for example, provides for the collar to comprise at least two collar sections which are arranged at a distance from one another in circumferential direction and for an internal threaded section of each collar section on the clamping element to extend in the clamping area, in an initial clamping position, in a necked in manner in the direction of the central axis deviating from a course of an internal threaded section on the base member. 
     This means that, in the clamping area, the internal threaded section on the collar deviates from a regular course of the internal threaded section on the base member, namely due to the fact that it is necked in in the direction of the central axis in order to achieve the clamping action when a threaded bolt is screwed in. 
     In this respect, it is particularly favorable when the internal threaded sections on the clamping element are increasingly necked in in the clamping areas with increasing extension of the clamping areas away from the base member. 
     In the simplest case, it is provided for the internal threaded sections on the collar to extend in the clamping areas in a necked in and conically tapering manner relative to the central axis in the direction away from the base member. 
     Such a solution may be produced particularly easily. 
     In addition, one advantageous solution provides for the collar sections, in the initial clamping position, to have end areas which are located on both sides of the clamping areas and in which the internal threaded section on the clamping element extends in a radial direction relative to the central axis at least at a radial distance which corresponds to the radial distance of the course of the internal threaded section on the base member relative to the central axis. 
     This solution has the advantage that, as a result, the end areas of the collar sections do not contribute to the clamping action but rather the clamping action is generated merely in the clamping areas and so no damage to the threaded bolt can occur, in particular in the end areas of the collar sections, in particular with formation of chippings. 
     One particularly favorable solution provides for the internal threaded sections on the clamping element to extend in the end areas in a radial direction relative to the central axis at a radial distance which is greater than the radial distance of the course of the internal threaded section on the base member relative to the central axis. 
     In principle, a course of the internal threaded section on the clamping element as described above could be produced by way of corresponding machining of the internal thread in the area of the collar sections, in particular in the clamping areas or end areas thereof. 
     The course of the internal threaded section on the clamping element in accordance with the invention can, however, be produced in a particularly simple manner when it is achieved by way of plastic deformation of the collar sections which are produced in an original position in that the internal threaded section on the clamping element corresponds exactly to the internal threaded section on the base member with respect to their radial distances from the central axis and, subsequently, the course of the internal threaded section on the clamping element which deviates from this is achieved by way of plastic deformation of the collar sections in the clamping areas and, consequently, in the end areas. 
     In the simplest case, the clamping areas are subject to a deforming action radially inwards in the direction of the central axis in order to achieve the plastic deformation, whereby a plastic deformation of the end areas radially outwards away from the central axis results automatically on account of the essentially closed, circumferential course of the collar. 
     In principle, the collar and the collar sections could be designed cylindrically or in any other optional shape relative to the central axis. 
     One particularly favorable solution provides, however, for the collar to have at least two collar sections which have, in their clamping areas, a greater wall thickness in a radial direction relative to the central axis than in end areas of the collar sections which are located on both sides of the clamping areas. 
     This solution has the great advantage that a greater wall thickness is available in the clamping areas in order to apply the forces required for the generation of the clamping force while the lesser rigidity desired is present in the end areas as a result of the slighter wall thickness. 
     In principle, the wall thickness could vary between the clamping areas and the end areas in an irregular manner. 
     A solution is, however, particularly favorable, with which the collar sections have a continuously decreasing wall thickness in the direction of the end areas proceeding from the clamping areas. 
     A further, advantageous solution provides for the collar to have at least two collar sections which have, in their clamping areas, a greater wall thickness in a radial direction relative to the central axis than in side areas adjoining the clamping areas. 
     In this respect, it is expediently provided for the collar sections to have a continuously decreasing wall thickness in the direction of the side areas proceeding from the clamping areas. 
     Furthermore, it is preferably provided for the wall thickness to be less in the end areas adjoining the side areas than in the side areas. 
     One particularly preferred solution provides for the wall thickness of the collar sections to be at a maximum in the clamping areas. 
     Furthermore, it is expediently provided for the wall thickness of the collar sections to be at a minimum in the end areas. 
     One particularly expedient solution provides for the wall thickness in the end areas to be less than half the maximum wall thickness in the clamping areas so that, on the one hand, an adequately high rigidity is present in the clamping areas and, on the other hand, the necessary low rigidity in the end areas in order to avoid any damage to the threaded bolt, in particular the formation of chippings, by the end areas. 
     In order to obtain, in particular, a collar which extends around the threaded bolt receptacle in a closed manner, it is preferably provided for the end areas of successive collar sections to adjoin one another in circumferential direction so that the collar sections of this solution are all connected to one another and, therefore, supported relative to one another. 
     It is provided, in particular, for the end areas to adjoin one another in an area with a minimum wall thickness. 
     In the simplest case, the collar sections merge into one another in one piece in their end areas. 
     In order to achieve the clamping action according to the invention in an advantageous manner, it is preferably provided for the collar sections to be movable into a clamping position proceeding from their initial clamping position as a result of an essentially elastic deformation radially to the central axis. 
     This solution is of advantage since an essentially elastic deformation of the collar sections during the transition from the initial clamping position into the clamping position takes place and so the clamping force exerted by the collar sections in the clamping position is then permanently effective and, in addition, can be reproduced in the initial clamping position in the case of a defined geometry. 
     It is provided, in particular, for the collar sections, in the clamping position, to act on a threaded bolt, which is screwed into the threaded bolt receptacle, with their clamping areas with an elastic force caused by the elastic deformation and, therefore, achieve the desired clamping action in the clamping areas with the internal thread on the clamping element which abuts on an external thread of the threaded bolt in a manner acted upon by force. 
     Furthermore, it is advantageous in this case for the collar sections, in the clamping position, to extend with their end areas with clearance relative to the threaded bolt screwed in in order to avoid any damage to the threaded bolt, in particular any formation of chippings, by the end areas when the threaded bolt is screwed in. 
     With respect to the design of the collar, no further details have so far been given. 
     In principle, the collar could be designed as a separate part which is connected to the base member. 
     With respect to manufacturing technology, it is, however, particularly advantageous when the collar is integrally formed on the base member in one piece; in this respect, it is advantageous, in particular, when the collar is integrally formed on the base member in one piece by way of mass forming. 
     An additional, advantageous solution provides for the base member to be provided with a pressure flange and for the collar to be arranged on the base member on a side located opposite the pressure flange. 
     In the embodiments described above, the mention is of at least two collar sections. In accordance with the invention, several collar sections can, therefore, also be provided, for example, three and more collar sections with a clamping area each. 
     Preferably, the collar sections with the clamping areas are arranged such that the clamping areas are arranged with respect to the central axis in the manner of a plural symmetry, i.e., a two-fold or three-fold symmetry or a multiple thereof in order to achieve a clamping action on the threaded bolt which is symmetrical to the central axis. 
     Additional features and advantages are the subject matter of the following description as well as the drawings illustrating one embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective illustration of one embodiment of a securing nut according to the invention; 
         FIG. 2  shows a plan view of the securing nut according to the invention in the direction of arrow A in  FIG. 1 ; 
         FIG. 3  shows a side view in the direction of arrow B in  FIG. 2 , cut away in one half; 
         FIG. 4  shows a sectional view along line  4 - 4  in  FIG. 3 ; 
         FIG. 5  shows a side view similar to  FIG. 4 , cut away in one half, in an enlarged illustration showing an original position, an initial clamping position and a clamping position of clamping areas of the collar; 
         FIG. 6  shows an illustration similar to  FIG. 4  showing the original position, the initial clamping position and the clamping position of the collar and 
         FIG. 7  shows an illustration similar to  FIG. 5  with a threaded bolt screwed in in the clamping position of the collar. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One embodiment of a securing nut  10  according to the invention, illustrated in  FIG. 1 , comprises a base member  12  which is provided around its circumference with a key face contour  14 . 
     The base member  12  has on a first side  16  a pressure flange  18  and on a second side  20  a clamping element which is designated as a whole as  22  and is integrally formed on the base member  20  in one piece, in particular by way of mass forming. 
     As illustrated in  FIGS. 1 to 3 , a threaded bolt receptacle which is designated as a whole as  30  passes through the pressure flange  18 , the base member  12  as well as the clamping element  22 , extends coaxially to a central axis  32  and is provided with an internal thread  34 , the thread pitches  36  of which not only run in an internal threaded section  40  of the threaded pin receptacle  30  on the base member but also run in an internal threaded section  42  on the pressure flange which penetrates the pressure flange  18  as well as in an internal threaded section  44  on the clamping element which penetrates the clamping element  22 . 
     As illustrated in  FIGS. 1 ,  2  and  4 , the clamping element  22  is formed by a collar  50  which is integrally formed on the base member  12  in one piece, rises above its side  20  and has, for example, three collar sections  52   a ,  52   b  and  52   c , each of which has a clamping area  54   a ,  54   b ,  54   c , side areas  56   a ,  58   a ,  56   b ,  58   b ,  56   c ,  58   c  adjoining the respective clamping areas  54   a ,  54   b ,  54   c  on both sides and end areas  62 ,  64 , wherein each of the collar sections  52  merges into the other collar section  52  in one piece following the respective end areas  62   a ,  64   a ,  62   b ,  64   b ,  62   c ,  64   c.    
     For example, the collar section  52   a  merges with its end area  64   a  into the end area  62   b  of the collar section  52   b  and the collar section  52   b  merges with its end area  64   b  into the end area  62   c  of the collar section  52   c  which, for its part, again merges with the end area  64   c  into the end area  62   a  of the collar section  52   a.    
     As a result, the collar sections  52   a ,  52   b  and  52   c  form, altogether, the collar  50  which extends in a closed manner around the internal threaded section  44  of the threaded bolt receptacle  30  on the clamping element in a circumferential direction  66  with respect to the central axis  32 . 
     Furthermore, the collar sections  52  each vary with respect to their wall thickness radially to the central axis  32 , namely such that in the clamping area  54  the maximum wall thickness W max  is present whereas in the end areas  62 ,  64  the minimum wall thickness W min  is present and so, altogether, the collar sections  52  merge into one another in one piece with their end areas  62 ,  64  at the minimum wall thickness W min . 
     The minimum wall thickness W min  is preferably selected such that this corresponds at the most to double a penetration depth E of the respective thread pitch  36  into the wall of the end areas  62 ,  64  accommodating it. 
     In this respect, the wall thickness W min  is preferably selected such that a wall area which is not penetrated by the thread pitch  36  and has a thickness between 0.2 mm and 1 mm, preferably between 0.4 mm and 0.6 mm, remains in the respective end areas  62 ,  64  outside an outer radius R A  of the thread pitches  36 . 
     In contrast thereto, the wall thickness W max  in the clamping areas  54  is at least double the penetration depth E of the thread pitches  36 ; the wall thickness W max  is preferably between double and three times the penetration depth E of the thread pitches  36  into the respective wall. 
     In the embodiment illustrated, the collar sections  52  are designed—as illustrated, in particular, in  FIG. 2  and FIG.  4 —such that their cross-sectional shape is, altogether, like a sickle, wherein the wall thickness is continuously reduced from the maximum wall thickness W max  in the respective clamping area as far as the respective end areas  62 ,  64 . 
     The collar sections  52  preferably merge continuously into one another at their end areas  62 ,  64  with respect to their wall thickness W. 
     One exemplary embodiment provides for the entirety of all three collar sections  52   a ,  52   b ,  52   c  to have an outer contour similar to a trilocular outer contour. 
     In order to generate the clamping action of the clamping areas  54   a  according to the invention, the collar  50  is, as illustrated in  FIG. 5 , produced first of all in an original position, in which the internal thread  34  passes through the entire threaded bolt receptacle  30  with a constant inner and outer radius, i.e., not only the internal threaded section  40  on the base member but also the internal threaded section  42  on the pressure flange and the internal threaded section  44  on the clamping element ( FIGS. 5 ,  6 ). 
     As a result, the internal thread  34  also extends with its thread pitches  36 , in particular, in the internal threaded section  44  on the clamping element, which is comprised by the collar  50 , in the same way as in the internal threaded section  40  on the base member. 
     Subsequently, as illustrated in  FIGS. 5 and 6 , a deformation of the collar sections  52  takes place in the clamping areas  54  of these collar sections to the extent that they are deformed in a direction relative to the central axis  32  by way of plastic deformation into an initial clamping position so that the inner radius R I  and the outer radius R A  of the internal thread  34  vary, namely in such a manner that the inner radius R I  and the outer radius R A  of the internal threaded section  44  on the clamping element are smaller in the clamping areas  54  than the inner radius R I  and the outer radius R A  of the internal threaded section  40  on the base member and are greater in the end areas  62  and  64  than those of the internal threaded section  40  on the base member. In the initial clamping position, the outer contour of the entirety of the collar sections  52  approximates a trilocular outer contour to an even greater extent. 
     In the initial clamping position, the internal threaded section  44  on the clamping element preferably extends in the clamping areas  54  conically to the central axis, i.e., an inner radius R I  thereof is increasingly reduced in size in the clamping areas  54  with increasing distance from the base member  12  and, consequently, a side of the clamping areas  54  located remote from the base member  12  has the smallest possible inner radius R I  from the central axis  32 . 
     When a threaded bolt  70  is screwed into the threaded bolt receptacle  30  ( FIG. 7 ), a clamping action is achieved in the clamping areas  54  of the collar sections  52  with an external thread  72  of the threaded bolt  70 , wherein in order to achieve the clamping action proceeding from the initial clamping position, a deformation of the clamping areas  54  takes place with an increase in the inner radius R I  and the outer radius R A  into a clamping position, wherein this is an essentially elastic deformation of the clamping areas  54  which therefore causes a permanent elastic force of the internal threaded section  44  on the clamping element acting on the external thread  72  of the threaded bolt  70  and, therefore, generates the clamping action as a result of increased friction. 
     The elastic deformation of the clamping areas  54  does, however, take place only to such an extent that an inner radius R I  of the internal threaded section  44  on the clamping element is still smaller in the clamping areas  54  than the inner radius R I  in the internal threaded section  40  on the base member and, therefore, the clearance normally existing with a thread is no longer present. 
     As a result, a clamping action is present in the clamping areas  54  of the collar sections  52  in a reproducible and permanent manner. 
     In addition, during the transition from the original position into the initial clamping position, the plastic deformation of the clamping areas  54  has the effect that the end areas  62 ,  64  of the collar sections  52  move radially outwards with respect to the central axis  32  and, therefore, the inner radius R I  and the outer radius R A  of the internal threaded section  44  on the clamping element are always larger in the end areas  62 ,  64  than in the internal threaded section  40  on the base member and so, altogether, an increase in the clearance in the end areas  62  and  64  occurs in the case of the threaded bolt  70  screwed into the threaded bolt receptacle  30  and, therefore, damage to the threaded bolt  70  by the end areas  62 ,  64  can be avoided with certainty in the end areas  62 ,  64  without, in particular, the formation of chippings. 
     This will also be achieved, in particular, in that the collar sections  52  merge into one another in the end areas  62 ,  64  and, therefore, support one another so that, on account of the geometrical ratios, the plastic deformation of the clamping areas  54  radially inwards automatically results in a plastic deformation of the end areas  62 ,  64  radially outwards in order to bring about the desired increase in the inner radius R I  and the outer radius R A  of the internal threaded section  44  in the end areas  62 ,  64  which are subsequently reduced again when the threaded bolt  70  is screwed into the threaded bolt receptacle  30 . 
     The course of stresses in a base area  80  of the clamping areas  54  is likewise illustrated in  FIG. 7 , wherein it can be seen that compression stresses occur in the base area  80  located radially outwards whereas tensile stresses occur in the base area  80  located radially inwards and, together, they act on the clamping area  54  with an elastic force in the direction of the central axis  32  in order to achieve the clamping action with the external thread  72  of the screw bolt  70 .