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TECHNICAL FIELD  
       [0001]     This invention relates to sliding panel assemblies, and in particular to interlocks for multi-panel sliding doors.  
       BACKGROUND ART  
       [0002]     Sliding panel doors are popular for applications where a large doorway must be closed. But when such a door is open, the panels should unobtrusively occupy a minimum volume of space. Applications range from closet doors to room dividers for banquet halls. A plurality of panels can be used, depending on the desired sliding panel size and the size of the entryway. During opening and closing, a lead panel is typically moved along a track. As force is applied to the lead panel, it engages a second panel to be drawn along in the direction of the force applied to the lead panel. The lead panel engages and “catches” the second panel by means of corresponding interlocks that engage each other when the lead panel moves toward or away from the second panel. The second panel can then, in turn engage a third panel, through another interlock, and so on. In this manner, by moving the lead panel, all of the panels in a door assembly can be deployed.  
         [0003]     In particular, it is desirable that when opening or closing such a multi-panel door, that the action be smooth and relatively silent. Conventional sliding panel interlocks can be noisy and jarring when they engage. Additionally, when the weight of the panels is relatively heavy, the interlocks and/or panels themselves can be damaged during the opening or closing of the panels.  
       SUMMARY OF THE INVENTION  
       [0004]     Embodiments of the present invention provide for shock absorbing interlocks for multi-panel sliding doors that operate smoothly and relatively noiselessly. In one embodiment, the interlock includes an internal shock absorber, and an external contact shock absorber, with friction bearing contacts. An optional motion dampening component can additionally absorb shock.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1   a  illustrates the closing of a three panel sliding door according to an embodiment of the invention.  
         [0006]      FIG. 1   b  illustrates the three panel sliding door of  FIG. 1   A  in a closed position.  
         [0007]      FIG. 2  illustrates the interlocking of a pair of adjacent sliding panels according to an embodiment of the invention.  
         [0008]      FIG. 3   a  illustrates an embodiment of the invention using a helical spring shock absorber, prior to interlocking.  
         [0009]      FIG. 3   b  illustrates the embodiment of  FIG. 3   a  when interlocked.  
         [0010]      FIGS. 4   a  through  4   c  illustrate embodiments with alternative shock absorbing elements.  FIG. 4   a  uses a helical spring shock absorber.  FIG. 4   b  uses a foam insert shock absorber.  FIG. 4   c  uses an elastomeric shock absorber.  
         [0011]      FIG. 5  illustrates a cross-sectional view of a housing member according to an embodiment of the invention.  
         [0012]      FIG. 6  illustrates a cross-sectional view of a sliding insert member according to an embodiment of the invention.  
         [0013]      FIG. 7  illustrates a cross-sectional view of a housing member assembled with a sliding insert member according to an embodiment of the invention.  
         [0014]      FIG. 8  illustrates a cross-sectional view of an embodiment of the invention with additional components.  
         [0015]      FIG. 9  illustrates an exploded, perspective view of the embodiment of  FIG. 8 .  
         [0016]      FIG. 10   a  illustrates a side, cross-sectional view of another embodiment of the invention, using a leaf spring shock absorber.  
         [0017]      FIG. 10   b  illustrates a top, interior view of the embodiment of  FIG. 10   a.    
         [0018]      FIG. 11   a  illustrates a side, cross-sectional view of the embodiment of  FIG. 10 , showing additional components.  
         [0019]      FIG. 11   b  illustrates a top, interior view of the embodiment of  FIG. 11   a.    
         [0020]      FIG. 12  illustrates a side, cross-sectional view of the embodiment of  FIGS. 11   a  and  11   b , installed on a pair of adjacent sliding panels. 
     
    
       [0021]     Commonly numbered drawing elements in the various figures refer to common elements of the embodiments of the invention. The drawings of the embodiments shown in the figures are not necessarily to scale. The drawings of the embodiments shown in the figures are for purposes of illustration only, and should not be construed to limit the scope of the invention.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0022]      FIGS. 2   a  and  1   B  illustrate the operation of a three panel sliding door. Individual panels  106   a ,  106   b , and  106   c  travel on a set of tracks  103  to open and close. The travel can be facilitated by slides, rollers, or other types of bearings. An additional set of tracks or channels is usually provided for the tops of the panels, to maintain them in vertical positions, however this is not shown.  FIG. 1   a  illustrates the open position of the door, and  FIG. 1   b  illustrates the closed position. In some embodiments, the panels can slide entirely into a wall, opening up the entire entryway  101 .  
         [0023]     In preferred embodiments it is only necessary to apply force to sliding panel  106   a , because sliding panel  106   a  mechanically interlocks with adjacent sliding panel  106   b , which in turn can mechanically interlock with panel  106   c , drawing all of the panels across the opening  103 , in this three panel example. Although  FIGS. 1   a  and  1   b  illustrate a three panel sliding door, in general there may be more or fewer than three panels, depending on the desired panel size, and the size of the entryway  101  to be closed.  
         [0024]      FIG. 2  illustrates a configuration of interlock assemblies on adjacent sliding panels according to one embodiment of the invention. Interlock assemblies  201   a  and  201   b  on sliding panels  106   a  and  106   b , respectively engage as indicated by the bold arrows. In some embodiments, interlock assemblies  201   a  and  201   b  can be of substantially identical design. Although as illustrated in  FIG. 2 , interlock assemblies  201   a  and  201   b  extend substantially the vertical lengths of their respective sliding panels, alternatively they may extend only partially over the vertical lengths in one or more segments configured to interlock the sliding panels.  
         [0025]     In order to illustrate a high level operation of one embodiment of the invention,  FIGS. 3   a  and  3   b  show cross-sectional views of pre-interlocked, and interlocked states, respectively, of an interlock assembly mounted on a sliding panel  106   b  (when viewed upwardly from the bottom of sliding panel  106   b  toward the top of sliding panel  106   b ). Sliding insert member  301   b  is assembled with interlock housing member  304   b , which includes an internal channel  303   b  for slidably holding a portion of the sliding insert member  301   b  therein. In one embodiment, the sliding insert member  301   b  and the interlock housing member  304   b  extend substantially along the entire length of housing  304  (normal to the plane of the illustration). The sliding insert member  301   b  includes an engagement lip  305   b , that catches and engages with a corresponding engagement lip  305   a  of interlock  201   a  (shown in  FIG. 2 ). An internal shock absorber comprising spring  302   b  absorbs shock as interlock assembly  201   a , mounted to sliding panel  106   a , engages interlock assembly  201   b  mounted to panel  106   b  as shown in  FIG. 3   b . In one embodiment, interlocks  201   a  and  201   b  are structures having a common design.  
         [0026]      FIGS. 4   a ,  4   b , and  4   c  illustrate different internal shock absorbing options according to different embodiments of the invention.  FIG. 4   a  shows a helical spring  302   b  as in  FIGS. 3   a  and  3   b .  FIG. 4   b  shows a resilient polymer foam shock absorber  401   b.  The foam may be of open or closed cell type, comprising a resilient polymer such as polyurethane or latex. Shock absorber  401   b  can extend substantially the length of interlock housing member (normal to the plane of the illustration).  FIG. 4   c  illustrates the use of an elastomeric shock absorber  402   b . In one embodiment, the elastomer can be configured with corrugated sections to enhance the extent of reversible deformation during shock absorption. The elastomer material can be polyurethane, latex, or the like.  
         [0027]      FIG. 5  illustrates a detailed cross-sectional view of an interlock housing member according to one embodiment of the invention. Top surface  509  is configured with holding ridges  503   a ,  503   b ,  503   c , and  503   d  configured to hold two substantially parallel friction bearing, and/or shock absorbing gaskets (not shown) for contact with an adjacent sliding panel. Although as illustrated, there are provisions for two such gaskets, there could alternatively be one gasket, more than two gaskets, or no gaskets. Ridges  502   a  and  502   b  are configured to hold a sliding insert member in place, whereas ridges  501   a  and  501   b  are configured to hold an internal shock absorber in place. Pedestals  504   a ,  504   b , and  504   c  are configured to lift the interlock body member  304   b  slightly away from a panel to which it is mounted. Gaskets (not shown) may be placed between pedestals  504   a ,  504   b , and  504   c  prior to fastening the base  505  to a sliding panel. Extended base  505 , has screw holes  506  formed therein periodically along the dimension normal to the illustration for mounting the interlock housing member to a sliding panel.  
         [0028]     The interlock housing member  304   b  of  FIG. 5  can be extruded, normal to the plane of the illustration, and cut to a desired length. The material can be a metal or alloy such as aluminum or brass, or a polymer such as ABS, or a composite material. Alternatively, interlock housing member  304  can be machined and/or molded through a variety of techniques that are well known to one of ordinary skill in the art. Note that in some embodiments the interlock assemblies are “gender less,” meaning that only one type of interlock assembly is necessary, the one type of interlock assembly being able to mate with other interlock assemblies of the same type.  
         [0029]      FIG. 6  illustrates a cross-sectional view of sliding insert member  301   b  according to an embodiment of the invention. Engagement lip  605  is coupled through sections  603  and  601  to plunger section  602 . In embodiments of the invention where the interlock housing member  304   b  and the sliding insert member  301   b  are assembled prior to being affixed to a panel, coupling section  601  has periodically positioned access holes  607  for access to screw heads of screws used to affix affixing interlock body member  304   b  to sliding panel  106   b  when coupling section  0601  is assembled with interlock body member  304   b . Ridges  606   a  and  606   b  are configured to hold a shock absorbing member for contacting the lip of an interlock on an adjacent sliding panel. Plunger section  602  contacts shock absorbing material at its distal end. Plunger section  602  is shown with optional ridges. Sliding insert member  301   b  can be fabricated using materials and techniques as discussed above, in connection with interlock housing member  304   b.    
         [0030]      FIG. 7  illustrates a cross-sectional view of sliding insert member  301   b  assembled with interlock housing member  304   b . As illustrated, the plunger section  602  of sliding insert member  301   b  can travel left and right within cavity  303   b  of interlock housing member  304 .  FIG. 8  illustrates a cross-sectional view of the interlock assembly of  FIG. 7 , with additional components according to an embodiment of the invention. External shock absorber insert  801  is configured to contact the lip of an interlock assembly on an adjacent sliding panel. External shock absorber  801  can be made of the same open, or closed cell foam, or elastomeric material as shock absorber  402 , or of a different material with shock absorbing properties, including, for example, felt or the like. Inserts  802   a  and  802   b  can be friction bearing and/or shock absorbing gaskets that can promote a smooth gliding action between adjacent panels. They can, for example, be made of polyfluorocarbons such as Teflon®, a registered trademark of the Dupont Chemical Company, or foamed polyfluorocarbons. Gaskets  803   a  and  803   b  can fill the areas between the interlock housing member pedestals, to provide for further sound and/or vibration and shock dampening. These gaskets may be formed from elastomers, foamed, elastomers, felt, or the like. Mounting screw hole  506  is shown positioned under mounting screw access hole  607 . A mounting screw can penetrate through gasket  803   a  for mounting an interlock on a sliding panel.  
         [0031]      FIG. 9  illustrates an exploded, perspective view of the embodiment of  FIG. 8 . In some embodiments interlock housing member  304   b  can be closed at one or both ends to prevent the sliding insert member  301   b  from sliding out of interlock housing member  304   b  in a direction substantially orthogonal to sliding insert member  301   b &#39;s motion during interlock operation.  
         [0032]      FIG. 10   a  illustrates a cross-sectional view of another embodiment of the invention, whereas  FIG. 10   b  shows a top view of the same embodiment, with the top cover of interlock housing member  304   b  removed for purposes of illustration. In this embodiment, a leaf spring  1003  functions as an internal shock absorber, and is affixed to sliding member  301   b  by rivets  1004   a  and  1004   b . Alternatively, the rivets may be replaced by nut and bolt assemblies, or the leaf spring may be affixed to sliding member  301   b  using a variety of other techniques such as welding, soldering, adhesives, clips, and so forth, as are well known to one of ordinary skill in the art.  
         [0033]     Referring to  FIG. 10   b , slot  1007  allows horizontal movement of sliding insert member  301   b  about a post inserted through hole  1006  in interlock housing member  304   b , while limiting the vertical movement of sliding insert member  301 . The mounting screw access hole  607  of sliding insert member  301  is shown positioned over the mounting screw hole  506  of interlock housing member  304   b . Referring again to  FIG. 10   a , post  1005  is shown positioned through the top and bottom surfaces of interlock housing member  304   b , passing through slot  1007  of the sliding insert member as shown in  FIG. 10   b . Post  1005  may be a rivet, a bolt and nut assembly, or a post affixed within interlock housing member  304   b , at its first and/or second ends using a variety of techniques, such as welding, soldering, adhesives, press-fit, and so forth as are well known to one of ordinary skill in the art. In alternative embodiments, the housing member  304   b  is simply closed at its bottom end to prevent the sliding insert member  301   b  from sliding vertically downward during operation.  
         [0034]      FIG. 11 a  is a cross-sectional drawing illustrating the embodiment of  FIG. 10   a , with additional components, and installed on a sliding panel  106   b . Gaskets  802   a  and  802   b  are friction bearing and shock absorbing members as described in connection with the above embodiments. Shock absorbing member  801 , is configured to contact the engagement lip of an interlock assembly on an adjacent sliding panel, as described above in connection with the other embodiments. Gaskets  803   a  and  803   b  are likewise as described above in connection with the other embodiments. Dampening insert  1101  is affixed to sliding insert member  301   b  and is configured to dampen the horizontal motion of sliding insert member  802 , through friction with an adjacent inside surface of interlock housing member  801 . Dampening insert  1101  can be made of elastomeric material, or open or closed cell foams, as described above in connection with the internal shock absorber. In some embodiments dampening insert  1101  has a ribbed surface for contacting the adjacent inside surface of interlock housing member  304   b , to further enhance frictional damping. Dampening insert  1101  can be affixed to sliding insert member  301   b  by adhesives, or similar means, or it may be simply held in place by walls  1005   a  and  1005   b  of sliding insert  301   b . Dampening insert  1101  can suppress a tendency of the interlocks to bounce when first engaged. Screw  1102  is shown installed through its hole in interlock housing member  304   b , through gasket  803   a , and driven into sliding panel  106   b .  FIG. 11   b  is a top view of the embodiment of  FIG. 11   a , with the top cover of interlock housing member  304   b  removed for purposes of illustration. Dampening insert  1101  has a slot  1107  formed therein to allow sliding motion of the sliding insert. Slot  1107  can also constrain the vertical motion of dampening insert  1101  that is normal to the sliding motion during operation.  
         [0035]     Although the embodiments of  FIGS. 11   a  and  11   b  have been illustrated with a leaf spring  1003 , a plurality of leaf springs may be used along the vertical length of sliding insert member  304 . Also, the leaf spring may be replaced with the other types of shock absorbers as described in connection with  FIGS. 4   a ,  4   b , and  4   c.    
         [0036]      FIG. 12  illustrates an operation of an embodiment of the invention, wherein sliding panel  106   a  slides along and interlocks with sliding panel  106   b , as illustrated by the arrows. Interlock assembly  201   a  is mounted to sliding panel  106   a  using one or more screws  1201   a . Interlock assembly  201   b  is mounted to sliding panel  106   b  using one or more screws  1201   b . As the interlock engages, the lip of interlock assembly  201   a  contacts the lip contact external shock absorber  801  in ( FIG. 8 ) of interlock assembly  201   b , and the lip of interlock assembly  0201   b  contact the lip contact external shock absorber of interlock assembly  201   a . Additional contact shock is absorbed by the internal shock absorbers of interlock assemblies  201   a  and  201   b , as the force is coupled through their respective sliding insert members.  
         [0037]     Variations and extensions of the embodiments described are apparent to one of ordinary skill in the art. Other applications, features, and advantages of this invention will be apparent to one of ordinary skill in the art who studies this invention specification. Therefore, the scope of this invention is to be limited only by the following claims.

Summary:
Embodiments of the present invention provide for shock absorbing interlocks for multi-panel sliding doors that operate smoothly and relatively noiselessly. Some embodiments combine external and internal shock absorbers, with friction bearing contacts. An optional motion dampening component can additionally absorb shock.