Patent Abstract:
A fastening system to press together 2 work pieces. These are plates with a circular aperture on each plate. The first work piece is engaged to the second work piece through a biased engagement. The receptacle assembly consists of a housing and its mechanical contents attached to the first work piece. The bolt assembly consists of a cylindrical bolt with a head and a shank attached and captured thru a retaining bracket to the second work piece and is moveable with respect to the receptacle assembly between the extended and retracted position. Two or more disc springs inside the housing bias the fastener toward the locked position with a biasing force. The bolt fastener has 2 opposing spiral cam slots machined on its shank and when introduced into the pin ring, inside the housing, will engage 2 radial placed cross-pins in its cam slots. Said cross-pins are seated in the pin ring. When the bolt fastener is rotated from the extended position to the retracted position it will lift the cross-pins and with it the pin ring against the disc springs and compressing them so as to provide a biasing force to press the first work piece in engagement with the second work piece.

Full Description:
[0001]    This application claims the benefit of provisional patent application Ser. No. U.S. 60/776,111, filed Feb. 23, 2006 by the present inventors. 
     
    
     FEDERALLY SPONSORED RESEARCH  
       [0002]    Not applicable 
       SEQUENCE LISTING OR PROGRAM  
       [0003]    Not applicable 
       FIELD OF INVENTION  
       [0004]    Fastener 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Reference cited: 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 US patents: 
                   
                   
               
               
                   
                 3,874,041 
                 Smith, 
                 1975 
               
               
                   
                 4,067,090 
                 Schenk 
                 1978 
               
               
                   
                 4,227,287 
                 Gunther 
                 1980 
               
               
                   
                 4,308,646 
                 Schenk 
                 1982 
               
               
                   
                 4,378,615 
                 Gunther 
                 1983 
               
               
                   
                 4,522,541 
                 Bidwell 
                 1985 
               
               
                   
                 Pub. No. 
               
               
                   
                 US 2005/0008458 A1 
                 Keech 
                 (abandoned) 
               
               
                   
                   
               
             
          
         
       
     
       BACKGROUND OF THE INVENTION  
       [0005]    Quarter turn fasteners of the quick release type, are well known and have been in use for many years. The present disclosure overcomes some of the shortcomings with prior art fastening systems that include S-shaped coiled springs or helical springs which show in special applications fatigue limitations and limited resistance to vibrations, limited cycle time and limited G-forces. Previous designs show bolt fasteners having a hollow end and having two spiral cam slots on the shank of the bolt fastener cutting thru to this hollow end. A cross pin of limited diameter goes thru these spiral cam slots across the bolt fastener. The hollow end and the two cut thru cam slots remove a lot of material from the bolt shank and created together with the cam cut-out 2 cantilevers on the end of the fastener, which weakens the fastener against axial forces. Cross pins of limited diameter can take only limited bending forces. Some of the designs of previous art show all the parts, or some of the parts exposed to dirt and weather. Some of the designs show bolt tracks of inefficient manufacturing design. In addition it has been difficult to retain a bolt fastener together with the second work piece, as some of the designs show them as non-captive and the bolt fastener might be misplaced or lost when disengaged from the first work piece. 
         [0006]    This high strength fastener is particularly designed to work in high vibration areas on aircraft and especially in helicopters which have a combination of strong vibrations and high g-forces, where a strong clamping force is required but where easy and quick assembly and disassembly with common hand tools is a required. Previous designs have shown that common fastener of quarter turn design either fatigued prematurely in this environment, fail structurally and brake, or eat themselves into the skin of the aircraft. This results in repeated downtime and expensive repairs. Another requirement in this industry is that the fastener has to be able to withstand repeated assembly and disassembly calling for up to 5000 cycle per fastener. Another consideration is the fact that the fastener has to resist weather and dirt penetration, and that it has to be attached to the skin by riveting or other reliable attachment means. U.S. Pat. No. 4,522,541, Bidwell, U.S. Pat. No. 4,308,646 Schenk, U.S. Pat. No. 3,874,041 Smith, shows a rectangular semi enclosed housing, made of plate material, with a helical spring, thin tabs or cross members are reaching into the spiral cam slots they are of rectangular design with sharp corners, which will not hold up in a high vibration area because of stress points on the corners and eating of corners. U.S. Pat. No. 4,227,287, Gunther, U.S. Pat. No. 4,378,615, Gunther, have an enclosed housing but act on a relative thin cross pin and use a bore in the lower part of the bolt with additional cut out tracks, which weakens the bolt and creates 2 cantilevers on the bolt end. They use helical springs as means of bias. U.S. Pat. No. 4,067,090, Schenk, is different in character, totally open and use tabs with sharp corners. Published and abandoned patent Pub. No. US2005/0008458, Keech, uses a thin cross pin and hollowed bolt with cantilever problems and has the disc springs on the outside exposed to weather. U.S. Pat. No. 4,442,561 Gunther, shows a slotted fastener, similar to our design. The difference is in the design of the cam slot. The patent shows a track with a steep “substantial continues radius of curvature” as claimed. Further in the description the detent is mentioned that a “depression is cut”, which creates a sharp “hump”. Our design critically avoids this sharp hump but shows in its character a shallow summit area. Our helix is not steep and radius like but is a straight helix on a shallow climb angle. Our bolt tracks are more than quarter turn and likens more to a third turn covering up to 120 degrees of bolt rotation. Our cross pins are short and thick of hardened and ground material and are captured in the pin ring. They can rotate in the pin ring when climbing the cam slots. In our preferred embodiment we use stacks of disc springs which require high forces to compress on very limited travel. The housing is totally enclosed and encapsulated with a lid. All the parts are pre assembled and package as a receptacle assembly and a bolt assembly. All what the assembler has to do is to rivet these assemblies to the upper and lower work pieces. 
         [0007]    This fastening system has the advantage over previous art that it is easy and fast to install and remove with common tools, it is a robust and durable design for the high vibration environment,and needs only a 90 to 120 degree rotation of the bolt fastener. The bolt fastener is solid and not hollow at its shank end. The design has an enclosed housing which prevents moisture and dirt to enter the internal parts. 
         [0008]    The cross-pins which engage in the opposing spiral cam slots of the bolt fastener are short and larger in diameter, designed for high shear forces and they can turn when climbing the cam slots of the bolt fastener this motion reduces friction and increases the life of the part. The springs are of the disc spring (Belleville washer) type which have the characteristic to create high spring forces on very small incremental compression. Placed in the receptacle assembly beneath the bolt fastener is a helical coil spring. When the bolt fastener is not engaged, said bolt fastener is lifted by the helical coil spring. This way the head of the bolt fastener will protrude, and indicate to the operator that this fastener is not tightened. 
       SUMMARY  
       [0009]    The high strength fastening system of the present disclosure consists of a bolt fastener assembly and a receptacle assembly which is designed to press together plate members here called work pieces. The work pieces comprise mainly of a lower and an upper plate with circular apertures in each plate. The first work piece which is the lower plate member is engaged to the second work piece which is the upper plate member thru a biased engagement. The first work piece consists of a receptacle that is a cylindrical housing that forms 2 chambers. The second work piece consists of a bolt with a head and is able to slide with respect to the receptacle between an extended and retracted position. Two or more disc springs also called “Belleville washers” bias thru resilience the bolt towards the locked position with a biasing force. The bolt fastener has 2 spiral indentations 180 degrees offset on its shank, which is adaptable to be inserted into a member of the receptacle. When the bolt fastener is rotated a pair of cross pins seated in the pin ring follow the cam slots in the bolt fastener upwards and they lift the pin-ring towards the disc springs and compresses them so that a force is transferred thru the bolt fastener, and bolt fastener head, to the second work piece, which will exert a biasing force against the first work piece. As the first work piece is detained by the bolt fastener head, clamping is archived between the first work piece and the second work piece. 
         [0010]    The bolt fastener assembly and the receptacle assembly are configured such that they may attach or release with more of a quarter turn up to a third turn of the bolt fastener, the bolt fastener having a slot or other turning means on its head to accommodate a screw driver or other tools to exert torque on the bolt fastener. Additional features of the present disclosure will be shown and become apparent to those skilled in the art, upon explanation and description of the drawings. 
     
    
     
       GENERAL DESCRIPTION OF THE DRAWINGS FIGURES  
         [0011]      FIG. 1  is a cross-sectional view of the bolt assembly and the receptacle assembly. 
           [0012]      FIG. 2  is a perspective view of the bolt assembly and the receptacle assembly. 
           [0013]      FIG. 3  shows a perspective view of the first and second work piece, the bolt fastener is tightened. 
           [0014]      FIG. 4  shows a perspective view of the first and second work piece engaged, but the bolt fastener is not tightened (sticking out) 
           [0015]      FIG. 5  shows a cross section of the assembly. The first and second work pieces are in contact and the bolt fastener is tightened. The disc springs are compressed. 
           [0016]      FIG. 6  shows a perspective cross section with the first and second work piece in contact. The bolt fastener is in position but not tightened. 
           [0017]      FIG. 7  shows an exploded perspective cross section view of the bolt fastener assembly and the receptacle assembly. 
           [0018]      FIG. 8  shows an exploded view of the receptacle assembly. 
           [0019]      FIG. 9  shows a perspective cross section of the assembled fastener. An o-ring is added and a drain hole is shown. 
           [0020]      FIG. 10  shows an exploded view of  FIG. 9   
           [0021]      FIG. 11  shows a view from below where a housing with a narrow attachment flange and narrow housing lid is mounted to the first work piece. 
           [0022]      FIG. 12  shows a cross section of the assembled fastener, showing a strong helical spring as the biasing element, instead of disk springs. 
           [0023]      FIG. 13  shows the first work piece having several disc springs, stacked in parallel and in series. 
           [0024]      FIG. 14   a ,  14   b ,  14   c , show pin ring arrangements with pins of different configurations. 
           [0025]      FIG. 17   a ,  17   b ,  17   c , show the bolt fastener with different groove-configurations of the opposing spiral cam slots. 
           [0026]      FIG. 18  shows a cross section of a receptacle assembly designed with a groove in-cut in the housing, and a snap ring located in the groove. 
           [0027]      FIG. 19  show the same as  FIG. 18  but in perspective view. 
           [0028]      FIG. 20  shows the fastener assembly in cross sectional view. The helical coil spring is located in the pocket of the retaining bracket. The bolt fastener is engaged and the helical coil spring is contracted. 
           [0029]      FIG. 21  shows the fastener assembly in a cross sectional view. The fastener bolt is disengaged and the helical coil spring expanded. The bolt fastener sticks out. 
           [0030]      FIG. 22 ,  23 ,  24 ,  25 ,  26 ,  27  show anti-rotation versions of the receptacle, in perspective and exploded view. 
           [0031]      FIG. 31  shows a housing with a serrated rim on its upper edge assembled with the first work piece. 
           [0032]      FIG. 32  shows an exploded view of the housing and the first work piece. The housing shows said serrated rim. 
           [0033]      FIG. 33  shows a bolt fastener with the curve profile of the opposing spiral cam slots. 
           [0034]      FIG. 34  shows a cross section of a bolt fastener with an integrated inner element. 
           [0035]      FIG. 35  shows an exploded view of the bolt fastener with an integrated inner element. 
       
    
    
     DETAILED DESCRIPTION  
       [0036]    The high strength fastening system of the present disclosure in  FIG. 1 and 2  includes a receptacle assembly  52  and a bolt fastener assembly  51 . 
         [0037]    The receptacle assembly  52  is designed to be attached to the first work piece  56  such as a plate, having a flat surface around the fastener area  58  and a flat parallel surface on the other side of the first work piece. The first work piece  56  has a round bore  62 . The bolt fastener  54  in  FIG. 1 ,  2  is attached to a second work piece  64  which is a plate with 2 parallel surfaces. The bore  66   FIG. 1 ,  7 , is created to accommodate the bolt fastener  54  shown in  FIGS. 1 and 7 . 
         [0038]    The bolt fastener  54  is secured into place by a retaining bracket  68  in  FIG. 1 ,  7 . This retaining bracket  68  has an aperture  70  in  FIG. 7 , which is less in diameter than the shank diameter  76  of the bolt fastener  54 , and as the bolt fastener  54  has an incut  72   FIG. 1 ,  7  which is smaller in diameter than the aperture  70   FIG. 7  in the retaining bracket  68 . The bolt fastener  54  has play along its axis but will be captive along the incut  72   FIG. 7 , and will not fall away or get lost. The retaining bracket  68  has been crimpt  74   FIG. 7 , at its aperture  70  which will reduce the aperture  70  relative to the bolt fasteners outside diameter  76   FIGS. 1 ,  7  and hold the bolt fastener  54  captive. 
         [0039]    The retaining bracket  68  has holes  78   FIG. 2 , and the second work piece  64  has matching holes  80   FIG. 1 . These holes are in line, and the 2 pieces are held in place by means of rivets, screws or other fastener  82   FIG. 1 . 
         [0040]    The bolt fastener  54   FIG. 2 , includes an enlarged head  84  with a slot  86  or the like, in the upper area, to rotate the fastener into its locked and unlocked position by means of a tool. On the underside of the head is a reduced diameter neck  72   FIG. 1 . Beginning at the end of the shank  76  opposite to the head is a pair of opposing spiral cam slots  88   FIG. 1 ,  2 . Each slot is cut from the leading edge  90  and extends along the shank towards the direction of the head  84 . At a certain point the spiral cam slots  88   FIG. 2  tilts gradually more horizontal until they reach a maximum high-point in the curve. This would be called the dead point  94   FIG. 2  of the curve. The slot then starts to bend downwards and than comes to an end. This can be called the retaining area  96 . 
         [0041]    A housing  98  in  FIGS. 1 ,  7  is attached to the first work piece  56   FIG. 1  by means of rivets, screws or other fasteners  124 ,  FIG. 1 ,  7  which sit in pre drilled holes  102   FIG. 2 , and  FIG. 8 , which match the first work piece  56 , housing lid  120 , and the housing  98 . The housing  98  is hollow and is a stamped, drawn, machined or a sintered part. It steps up to an enlarged diameter  104   FIGS. 5 ,  7 ,  8  and a square or rectangular flange  106   FIG. 8 , with 4 holes  108  for attachment rivets or other fasteners. The housing has a flat surface  110   FIG. 8 , which serves as a detent against rotation of the pin ring  112   FIG. 8 . This pin ring  112  has a matching flat surface  114   FIG. 8 , which slides against the inside surface of the flat surface  110  in  FIG. 8  of the housing  98 . The housing is divided by a step into a upper chamber  116   FIG. 7  and a lower chamber  117 . The upper chamber is designed so it will accommodate 2 or more disk springs  118 , also called Belleville washers. The housing  98  has a housing lid  120  riveted to it. This housing lid  120  has 4 holes  122   FIG. 8 . It is designed to accommodate 2 rivets  100  to capture and lock the housing  98   FIG. 8  with the housing lid  120 , and 2 more rivets  124 , diagonally placed to them to fasten the housing lid  120  together with the housing  98  against the first work piece  56 . In this way the parts in the housing  98  are captured as an enclosed receptacle  52  before they get mounted to the first work piece  56 . 
         [0042]    The disk springs  118  in  FIG. 6 , are captured between the housing lid  120  and the pin ring  112  with a slight preload. The disc springs  118  are also restricted to move radially or side ways by the circular enclosure of upper chamber  116   FIG. 7 . These disc springs  118  can be stacked in such a way that the smaller inner peripheral edge of the disc springs  126   FIG. 8  is touching the smaller inner peripheral edge  128  of the next disc spring, and the larger outer peripheral edge of the disc spring  130   FIG. 8  is touching the larger outer peripheral edge of the next disc spring  132 . 
         [0043]    This results in an accordion like manner to stack the disc springs. When the stack is subject to a compression force in an axial or vertical direction, it will somewhat flatten and shorten, and when the force is removed it is getting longer and will return to its initial stack-height as shown in  FIG. 6 . 
         [0044]    The pin ring  112   FIG. 8 , is a circular tube with a flat anti rotation surface  114  machined into its cylindrical outer surface, and 2 drilled holes  136   FIG. 8  which are located radially to the axis of the pin ring  112 . These 2 holes hold 2 cross-pins  138  which are held with a press fit or loose fit in the holes  136   FIG. 8 . The cross-pins  138  are flush with the outside diameter of the pin ring  112  but protrude inward  140   FIG. 6  towards the centerline of the pin ring  112 . The diameter of these cross-pins  138  is less than the width of the opposing spiral cam slots  88   FIG. 7  of the bolt fastener  54 . The helical coil spring  142   FIG. 6 , is slightly less in its outside diameter than the inside diameter of the pin ring  112 . When the fastener bolt is in non engagement, the helical coil spring  142  has enough force to lift the fastener bolt  54  against its weight and friction, so that it visibly protrudes above the fastener assembly  144   FIG. 4 . This indicates to the operator that this bolt has not been tightened yet. The helical coil spring  142  in its expanded state has a slight preload when it touches the two pins  138   FIG. 6 , and is captured between the pins  138  and the bottom of the housing  146   FIG. 6 . 
         [0045]    First work piece  56   FIG. 1 , second work piece  64 , bolt fastener  54 , retaining bracket  68 , housing  98 , pin ring  112   FIG. 1 ,  7 , disc springs  118   FIG. 1 ,  8 , housing lid  120 , rivets  82 ,  100 ,  124 , cross-pins  138 , helical coil spring  142 , this parts which when assembled represent the high strength fastener may respectably be formed from metallic and or non metallic materials as an example but not limited: Steel, stainless steel, all steel alloys, titanium, aluminum, all aluminum alloys, plastic and composite materials including graphite, carbon, quartz, glass polymers and cellulose. 
         [0046]    OPERATION: Engagement and disengagement of the high strength fastener. The second work piece  64   FIG. 2  with the bolt fastener  54  attached, is introduced onto the first work piece  56  until surface  60   FIG. 2  touches surface  58  in  FIG. 2 . The bolt fastener  54  will than take the protruded position shown,  144   FIG. 4 . By introducing a screw driver blade into the slot  86   FIG. 4  of the head of the bolt fastener  54  and doing a slight turn clock wise until the opposing spiral cam slots  88   FIG. 6  of the bolt fastener engage the cross-pins  138 . Pushing the screw driver down will result in engagement of the cross-pins  138  into the opposing spiral cam slots  88   FIG. 6 . The opposing spiral cam slots  88  are now not more vertical in relation to the pins  138   FIG. 6  but have a slope of approximately 30 degrees. As the bolt fastener  54  is turned clock wise with the screw driver, the head  84  of the bolt fastener  54  descends and touches with its underside  148   FIG. 6  the retaining bracket  68   FIG. 7  and the cross-pins  138  start to climb with the pin ring  112  up the opposing spiral cam slots  88  and lift the pin ring  112  against the stacked disc springs  118 , and compressing them axially. The spring force increases steadily, as the pin ring is moved toward the spring stack. As soon as the cross-pins  138  reach over the dead point  94   FIG. 2  of the opposing spiral cam slot curvature, the compression force of the disc spring stack will force the cross-pins  138  down into the retaining area  96   FIG. 2  and create a locking action. This causes the disc spring stack to expand a small amount. The spring force will be still considerable and act as a lock-in force. This is caused with an approximately 90 to 120 degree turn of the bolt fastener  54 . When unlocking, the sequence of events of the high strength fastener, are in reverse. The screw driver has to turn the bolt fastener  54  counter-clock wise and overcome the spring force by compressing the stacked disc springs  FIG. 7  until the cross-pins  138  are over the dead point  94   FIG. 2  in the opposing spiral cam slots  88 . The stacked disc springs will release the spring force and return to its original stack height as the bolt fastener  54  turns. The bolt fastener  54  turns back to its starting angle. At the end of the turn, the bolt fastener has no vertical resistance from the cross-pins  138   FIG. 6 , as the opposing spiral cam slots  88  are vertical or almost vertical in relation to the cross-pins  138 . The helical coil spring  142   FIG. 6  will push the head up as shown in  144   FIG. 4 . If this fastener is in a row of fasteners, the operator will see that the head of this fastener sticks out and will know that this fastener is unlocked. 
       Additional Embodiments  
       [0047]    Another embodiment of the fastening system is shown in  FIG. 9 and 10 . The bolt fastener of this configuration has on the under side of the head  152   FIG. 9  a concentric groove  154   FIG. 10  which accommodates an o-ring  156  of soft rubber material or other plastic composites, which presses in the locked position against the retaining bracket  68 . This way moisture is prevented to enter the fastening system from the outside of the aircraft when it is in a locked position shown in  FIG. 9 , in addition a drain hole  160  is added to the bottom of the housing  158  located on the inside of the air craft. This eliminates moisture accumulation. 
         [0048]    Another embodiment of the fastening system is shown in  FIG. 12 . The disc springs  118   FIG. 7  are replaced by a very strong helical coil spring  168   FIG. 12 . 
         [0049]    The housing has no step. 
         [0050]    Another embodiment of the fastening system is the manner of arranging disc springs as shown in  FIG. 13 . To increase the spring force the disc springs are stacked in parallel  170   FIG. 13 . Example: Picture shows 3 disc springs stacked, and than the packet of parallel disc springs are stacked in series  172   FIG. 13 . 
         [0051]    Another embodiment of the fastening system is the manner to seat the cross pins to the pin ring.  FIG. 14   a  shows a straight cross-pin  138  which is seated in the pin bore with a press fit. 
         [0052]    Another embodiment of the cross pin is shown in  FIG. 14   b , the cross pin having a rounded end  186 . 
         [0053]      FIG. 14   c  shows a pin ring  173  with a counter sunk bore  174  on both sides. The cross-pins  176  have a flange  178  which are seated in the counter sunk bore  174 . This way the pin is captured between the inner surface  161  of the countersink  174  and the inner wall side of the housing  FIG. 18  item  217 . The fit between the cross-pin  176  and the bore  177  is either a loose fit so that the pin  176  can freely turn, or a press fit where the cross-pin is firmly in place and can not turn. 
         [0054]    Another embodiment of the fastening system  FIG. 17   a ,  17   b , and  17   c  shows cross-sections of the bolt fastener with different configurations of the opposing spiral cam slots.  FIG. 17   a  shows a bolt fastener with rounded opposing spiral cam slots  205 . In  FIG. 17   b  shows a bolt fastener with tapered opposing spiral cam slots  206 .  FIG. 17   c  shows a bolt fastener with square opposing spiral cam slots  208 . 
         [0055]    Another embodiment of the fastening system is shown in  FIG. 18  and  FIG. 19 . The housing  209  lacks the housing lid  120   FIG. 7 . There is a groove  210   FIG. 19  placed on the inner diameter of the housing  212 , which accommodates a snap ring  214 . The disk springs packet  184   FIG. 19  is located between the snap ring  214   FIG. 18  and the housing step  216 . This way the disk spring packet  184  is captured with a slight preload between the snap ring  214  and pin ring  112 . 
         [0056]    Another embodiment of the fastening system is shown in  FIG. 20 and 21 . Previously a helical coil spring was shown in  FIG. 5  item  142  between the bottom of the housing  146  and on the lower end  147  of the bolt fastener  54 . In this version of the embodiment of the fastening system, a helical coil spring  218   FIG. 21  is shown to be located underneath the bolt fastener head  224  and seated on the bottom  226  of the spring chamber  222  formed by the retaining bracket  220   FIG. 21 . The bracket is crimped to form said bottom  226   FIG. 20  to be able to retain the bolt faster. This design shows the operator that when the bolt fastener  228  is disengaged it is sticking up  230  due to the force of the helical coil spring  218  and when the bolt fastener  228  is engaged it is pressing down with the underside of the head  22  against the retaining bracket  220  and compressing the helical coil spring. 
         [0057]    Other embodiments of the fastening system are shown in  FIG. 22  to  FIG. 27 . One of the important objectives of this invention is to have a simple but efficient anti-rotation feature to prevent the pin ring to rotate, when the bolt fastener  54   FIG. 18  is turned, but by the same time to allow the pin ring  112   FIG. 18  to easy slide up and down and compress or release the disk spring stack  184 . 
         [0058]    This is shown in the preferred embodiment of the fastening system presented in  FIG. 22 and 23 . A flat surface  114  in the pin ring  112  contacts the flat inside surface  110  of the housing  98 . 
         [0059]    Another embodiment of the fastening system is shown in  FIG. 24 and 25 . One or two bolt-pins  232  are sticking out on one, or on opposite sides from the outside surface  234   FIG. 25  of the pin ring. These bolt-pins  232  run in a corresponding vertical slot  236   FIG. 24  of the housing  238 . Said bolt pins serve as an anti rotation devise. 
         [0060]    Another embodiment of the fastening system is shown in  FIG. 26 and 27 . A pin ring  240  is shown with 1 or 2 protruding vertical guides  242  protruding from the lower end of the pin ring  244 . Said guides  242  engage into 1 or 2 in-cuts  246  at the bottom  248  of the housing  250 . The guides are long enough to stay engaged into the in-cuts  246  to cover the full length of the vertical travel of the pin ring  240 . Said guides serve as an anti rotation device. 
         [0061]    As shown previously in  FIG. 5 , the receptacle  52  and all its contents attach to the first work piece  56  by means of rivet, blind rivets, screws or other fastening elements  124 . 
         [0062]    Another way to attach the receptacle is shown in  FIG. 31 and 32 , providing a self clinching serrated toothed rimmed surface  274 . The serrated toothed rimmed surface ends in a shoulder stepped in-cut  276 . When the housing  272  is pressed with its rim into the bore  280  of the first work piece  278  it will create a solid mounting for the receptacle. 
         [0063]    Another embodiment of the fastening system is shown in  FIG. 33 . The curve profile of the fastener shows special characteristic. Conventional quarter turn designs show a track in the bolt fastener where the curve starts at the distal end and continues in a curved radius-type helix. Our fastener enters vertical  290  at the distal end of the bolt fastener curves into a straight helix  292  of approximately 30 degrees incline, climbing the bolt fastener shank until it reaches the summit of the curve, here called the dead point  294 . This summit area covers 40 degrees of rotational movement  296 . The centerline  298  of the cam profile has a very shallow curve incline, and when leaving it ends in a retaining area  300 . The whole track is a continuous machined in-cut by CNC technology, or manufactured by cold forming or forging. 
         [0064]    Another embodiment of the fastening system is shown in  FIG. 34 and 35 . Pin ring, housing lid and a strong helical spring become one integral part here called inner element  302 . The inner element has a flat anti rotation surface  304 , bores for the cross-pins  306 , a helical spiral in-cut creating a spring  308  and a housing lid  310 . The internal bore has a loose fit with the bolt fastener  314 . The housing  316  has a cylindrical shape with a bottom  318  and a flange  320 . The outside diameter of the integrated element  322  has a loose fit with the inside diameter of the housing. The anti rotation surface of  304  of the inner element has a sliding fit with the inside of the flat surface  326  of the housing. 
         [0065]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.

Technology Classification (CPC): 5