Abstract:
A quick connect fastener wherein the receptacle is adjustable to allow different stud types to be used and wherein absolute clamp-up is provided through repeated cycling. A spring loaded lock plate that captivates the quarter turn cross-pin in the locked position against the adjacent cam surface is provided. The lock plate is positioned within the receptacle and indicates the correct locked position at absolute clamp-up when the lock plate snaps over the cross-pin. Two ramps on the lockplate provide a positive “feel” when installing or removing the stud and provide the detent/lock feature. The cam comprises two helixed ramps leading to flat surfaces or plateaus for the cross-pin to ride up and tighten against. The plateaus are adjacent to detent recesses on the lock plate which provide the locking capability.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    A quick connect fastener assembly for holding panels together wherein the fastener receptacle length is adjustable in a manner whereby full clamp-up is provided through repeated cycling.  
           [0003]    2. Description of the Prior Art  
           [0004]    Quarter turn stud fastener assemblies, or quick connect fasteners, have long been commercially available. Such fasteners include a grommet, stud and a receptacle, the fastener holding two panels together. As noted in U.S. Pat. No. 5,795,122 to Bowers, the drawback to the conventional quarter turn fastener is the total thickness of the two panels for which the fastener is effective must lie within a limited range; if the total thickness lies outside the range, a longer or shorter stud must be used. Thus, for most work applications, a variety of stud sizes must be purchased and kept on hand. To eliminate this problem, the Bowers patent discloses an adjustable receptacle. In particular, the receptacle includes an internally threaded body and an externally threaded barrel, wherein the threads of the body and the barrel are in engagement with one another so that rotation of the barrel relative to the body moves the barrel axially with respect to the body. Cam and locking surfaces for the cross pin of the stud are defined in the barrel. As a result, the position of the barrel within the receptacle body can be adjusted so that a single length stud can be used, and yet total panel thickness can be varied over a wide range.  
           [0005]    When the desired position of the barrel has been set, semicylindrical grooves of equal diameter are drilled parallel to the axes of the barrel and the cylindrical body in the outer circumference of the barrel and in the inner annular surface of the cylindrical body. With each complete revolution of the barrel relative to the cylindrical body, the drilled grooves are in alignment with one another and, when the desired position of the barrel is achieved, the grooves are aligned and a spring roll pin of appropriate diameter is inserted into the aligned grooves to lock the barrel in the desired position.  
           [0006]    The barrel member includes a pair of diametrically opposed curved slots which curve back toward the end of the barrel member and which define locking surfaces for the stud cross pin. However, this curve back feature causes a gap between the panels, during clamp-up, preventing full clamp-up, an undesirable condition in many fastener applications.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a quick connect fastener wherein the receptacle is adjustable to allow different single stud types to be used for panel members of variable thickness and wherein absolute clamp-up is provided with the use of a lock plate cam assembly configuration.  
           [0008]    A spring loaded lock plate positioned within the receptacle housing captivates the quarter turn cross pin in the locked position against an adjacent surface on the cam assembly. The lock plate indicates the correct locked position at absolute clamp-up when the lock plate snaps over the cross pin. Two ramps on the lower surface of the lock plate provide a positive “feel” when installing or removing the stud and provide the detent/lock feature. A crimped endcap on the housing prevents corrosive material from entering the interior of the receptacle and a crimped collar on the housing prevents the threaded cam assembly from being accidentally ejected from the rear of the housing during the initial installation process or subsequent depth adjustment of the cam assembly. The cam assembly includes two helixed ramps leading to flat surfaces, or plateaus, for the cross pin to ride up and tighten against a vertically extending surface on the cam assembly. The plateaus are adjacent to detent recesses on the lock plate which provide the fastener locking feature.  
           [0009]    The present invention thus provides a quarter turn stud assembly fastener which provides absolute clamp-ups, wherein a stud of a fixed length can be used with panel members having a range of thickness and wherein a spring loaded lock plate provides the locking feature. 
       
    
    
     DESCRIPTION OF THE DRAWING  
       [0010]    For a better understanding of the present invention as well as other objects and further features thereof, reference is made to the following description which is to be read in conjunction with the accompanying drawing wherein:  
         [0011]    [0011]FIG. 1 is a front elevational view illustrating the receptacle of the present invention holding two panel members together;  
         [0012]    [0012]FIG. 2 is a front elevational view illustrating the receptacle of the present invention holding two panel members together, the thickness of the panel members being less than the thickness of the panel members shown in FIG. 1;  
         [0013]    [0013]FIG. 3 is a bottom view of the receptacles shown in FIGS. 1 and 2;  
         [0014]    [0014]FIG. 4 is a top view of the receptacles shown in FIGS. 1 and 2;  
         [0015]    [0015]FIG. 5 is a cross-sectional view of the receptacle shown in FIG. 1;  
         [0016]    [0016]FIG. 6 is a cross-sectional view along line  6 - 6  of FIG. 5, FIG. 7 is a cross-sectional view along line  7 - 7  of FIG. 5;  
         [0017]    [0017]FIG. 8 is a cross-sectional view along line  8 - 8  of FIG. 5;  
         [0018]    [0018]FIG. 9 is a cross-sectional view showing the upper plate moving upwards when unlocking;  
         [0019]    [0019]FIG. 10 is a cross-sectional view showing the upper plate moving upwards when locking; and  
         [0020]    [0020]FIG. 11 is a cross-sectional view of the receptacle shown in FIG. 2. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0021]    Referring now to FIGS. 1, 3 and  4 , a front elevational, top and bottom views, respectively, of the novel quarter turn assembly, or quick connect fastener,  10  of the present invention is illustrated. The stud assembly comprises a grommet  12 , a receptacle assembly  14 , stud  16  and driving recess  17 . The quarter turn assembly  10  is used to secure panel members  18  and  20 , of a predetermined thickness, together. Flange portion  22  of receptacle assembly  14  is secured to the outside surface  24  of panel member  18  via metal fasteners  26  and  28  as illustrated.  
         [0022]    [0022]FIG. 2 illustrates the quarter turn assembly  10  joining panel members  30  and  32  together, panel members  30  and  32  having a total thickness less than the thickness of panel members  18  and  20 . In accordance with the teachings of the present invention, receptacle assembly  14  is adjustable to enable assembly  10  to accommodate panel members of varying thicknesses, grommet  12  and stud  16  being conventional items.  
         [0023]    [0023]FIG. 5 is a cross-sectional view of the assembly  10  shown in FIG. 1. In particular, grommet  12  is positioned into coaligned apertures  40  and  42  formed in panel members  20  and  22 , respectively. A coil spring  44  surrounds the portion of stud  16  within grommet  12 , stud  16  extending into receptacle assembly  14  as illustrated. A locking cross pin  46  is positioned adjacent one end of stud  16  in a conventional manner. A cam assembly  50  is positioned within housing  52 , housing  52  having a thread portion  54  formed along its internal diameter. The lower portion of cam assembly  50  has thread portion  56  formed on its outside diameter, threads  54  and  56  being in operative engagement as illustrated. A lock plate  60  having bores  62  and  64  located on its top surface, springs  66  and  68  being placed in bores  62  and  64 , respectively, is positioned above cam assembly  50  within receptacle assembly  14 . An endcap  70  is positioned over springs  66  and  68  and lockplate  60  to hold the components in place.  
         [0024]    Due to the varying thickness of the panel members, cam assembly  50  within housing  52  is initially set within a 0.25 inch range. The first installation of the stud  16  (or with the use of a special tool), will rotate the cam assembly  50  within the receptacle housing,  52  thus creating an axial movement. An installation tool (not shown) inserted in driving recess  17  provides the absolute clamp-up condition, the cam assembly  50  thus being set for its correct depth for a particular stud length. The cam assembly  50  cannot move axially during repeated cycling after the initial set due to the resilient fixing on thread portion  56 , the stud  16  thus always locating to the proper depth at full clamp up after repeated installations. In particular, in order to positively lock the cam assembly  50  with respect to the cylindrical receptacle housing  52 , when the desired position of the cam assembly  50  has been set as noted hereinabove, a Resilient fixing material is interposed between the threads of the cam assembly  50  and the threads of the cylindrical housing  52 . The resilient fixing material prevents movement of the cam assembly  50  relative to the housing  52  within the range of forces required to connect or disconnect the fastener. At a level of force beyond that required for connection and disconnection of the fastener, the resilient fixing material permits rotation of the cam assembly  50  and lock plate  60  while using a stud of fixed length. The resilient fixing material may be in the form of a nylon material surrounding the circumference of external thread portion  56  of cam assembly  50 . Alternately, housing  52  can be crimped or deformed out-of-round to provide a positive lock against the axial movement of cam assembly  50 .  
         [0025]    The fastener  10  is locked as follows:  
         [0026]    The stud cross pin  46  is passed through the aperture (bore) of cam assembly  50  and rotated until it passes through a matching rectangular cutout  53  (FIG. 6) therein. After cross pin  46  passes through the cutout  53 , stud  16  continues to be rotated clockwise such that the cross pin  46  travels up ramp portion  80  adjacent plateau  82  on cam assembly  50 , cross pin  46  striking helixed inverted ramps  84  formed on the bottom surface of the spring loaded lock plate  60 . As stud  16  continues to rotate, cross pin  46  lifts lock plate  60  until cross pin  46  engages plateau  82 . As stud  16  continues to rotate, cross pin  46  strikes the stop surface  86  of cam assembly  50 , surface  86  being substantially perpendicular to plateau surface  82 . Spring loaded lock plate  60 , after being moved towards the top surface of end cap  70 , returns to the extended position (away from endcap  70 ) providing the fastener locking feature. In particular, plateau surfaces  82  on cam assembly  50  provide the full clamp-up characteristic and the inverted ramps  84  on lock plate  60  provide the detent/lock characteristic of fastener  10 .  
         [0027]    The stud assembly  10  is unlocked as follows:  
         [0028]    Stud cross pin  46  is rotated counterclockwise along the plateau surface  82  of cam assembly  50 . The cross pin  46  then strikes the inverted ramps  84  on the adjacent spring loaded lock plate  60 . As stud  16  continues to rotate, cross pin  46  lifts lock plate  60  until cross pin  46  passes under the inverted ramps  84  on lock plate  60  and travels down ramp  80  of cam assembly  50 . Spring load lock plate  60  then returns to its extended position and stud  16  disengages from the receptacle assembly  14  as the cross pin  46  continues to rotate to, and passes through, the matching rectangular cutout  53  in cam assembly  50 .  
         [0029]    [0029]FIG. 6 is a cross-sectional view along line  6 - 6  of FIG. 5 and shows how cross pin (locking bar)  46  is locked, or secured within the receptacle assembly  14 . Cam assembly  50  includes two vertically extending protrusions  90  and  92  surfaces  86  thereon acting as a stop for cross pin  46 ; lock plate  60 , as noted hereinabove, has inverted helixed ramps  84  formed on its bottom surface.  
         [0030]    [0030]FIG. 7 is a cross-sectional view along line  7 - 7  of FIG. 5 showing cross pin  46  from a different direction.  
         [0031]    [0031]FIG. 8 is a cross-sectional view along line  8 - 8  of FIG. 5 showing the location of springs  66  and  68  within the bores formed in the top surface of lockplate  60 .  
         [0032]    [0032]FIG. 9 is a cross-sectional view of receptacle assembly  14  showing the locking plate  60  moving in the upwards direction when the quarter turn fastener assembly  10  is being unlocked. In this mode, as noted hereinabove, as stud  16  is rotated in the counter clockwise direction, cross pin  46  moves in the direction of arrow  100  and strikes inverted ramps  84 , moving lock plate  60  in the direction of arrow  102 . Cross pin  46  continues to move down ramp  80  past inverted ramps  84 , enabling lock plate  60  to return to the position shown.  
         [0033]    [0033]FIG. 10 is a cross-sectional view of receptacle  14  showing locking plate  60  moving in the direction of arrow  106  when the fastener assembly  10  is being locked. In this mode, as described hereinabove, as stud  16  is rotated in the clockwise direction, cross pin  46  moves in the direction of arrow  108 , striking inverted ramps  84 , moving lock plate  60  in the direction of arrow  106 . Cross pin  46  continues to move up ramp  80  until it sits on plateau  82  and against stop surfaces  86 . At this point, lock plate  60  moves in the direction opposite to arrow  106 , returning to the extended position.  
         [0034]    [0034]FIG. 11 is similar to FIG. 5 with the exception that the total panel thickness is less than the total thickness of panels  18  and  20 . In this situation, receptacle assembly  14  is initially rotated within housing  52  such that threaded housing portion  56  is moved further away from panel member  32  as illustrated, enabling the same stud  16  utilized in the FIG. 5 embodiment to be used to secure panel members  30  and  32  together.  
         [0035]    End cap  70  is preferably crimped to prevent corrosive material from entering the interior of the receptacle assembly. Housing  52  has a crimped collar  55  to prevent the threaded cam assembly  50  from being accidentally ejected from the rear of housing  52  during the initial installation process or subsequent depth adjustment of the cam assembly  50 .  
         [0036]    While the invention has been described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teaching of the invention without departing from its essential teachings.