Patent Publication Number: US-2005132873-A1

Title: Method of connecting rigid bodies and rigid body

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application is a continuation-in-part of U.S. application Ser. No. 10/744,485 filed Dec. 23, 2003, which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION  
     FIELD OF THE INVENTION  
      The invention relates generally to a method of constructing a body and more specifically to constructing a rigid body or a rigid volume.  
      The current trend in the armoring industry is to build fixtures using plates in which the materials used cannot be mechanically modified more than a certain percentage. Mechanical modification usually occurs partially or totally at the connection points or edges between adjacent panels. Usually the properties are changed because of the transformation of the properties of the materials themselves due to the changes in the crystal and grain matrix of the material because of the bonding method such as welding. For example, the heat from the welding process changes the mechanical/chemical properties of the panels being welded together and therefore critically changes the properties (e.g. weakens) of the panels.  
      A prior art solution is to forgo the welding process but requires the use of additional components for interconnecting the armored pieces. However, this results in added weight, additional components and complexity to the original body under construction. The increase in the number of parts requires increased manufacturing and installation costs and also increases the probability of failure in a system with the ever-increasing number of parts. In addition, the added weight has an impact on driveability should the structure be a vehicle and the need for a reinforced frame for bearing the extra weight.  
      An armored system acts as a fuse and is configured for absorbing significant amounts of energy from projectiles impinging on the armored components. The armored system modifies its own shapes and sometimes its properties while absorbing the energy. Therefore structures assembled with armor plating cannot be tested individually but by statistical testing so that a confidence in prediction based upon results of the tests satisfies the requirements. In this way the real level of quality of the armored structure depends on the quality of the armored plates and the modification or their properties while being treated and/or assembled. Therefore, the armored plating that is the least handled and modified is the most reliable as its properties is the least changed during assembly (e.g. subjected to welding heat).  
     SUMMARY OF THE INVENTION  
      It is accordingly an object of the invention to provide a method of connecting rigid bodies and a rigid body that overcome the above-mentioned disadvantages of the prior art devices and methods of this general type, which provides better mechanical properties without increasing assembly time and complexity.  
      With the foregoing and other objects in view there is provided, in accordance with the invention, a construction method. The method includes providing a first panel having an opening formed therein, providing a second panel having a tab extending therefrom, inserting the tab of the second panel into the opening of the first panel, and fixing the first panel to the second panel only in an area of the opening.  
      In accordance with an added feature of the invention, the first and second panels are bullet-resistant and/or armored panels.  
      In accordance with an additional feature of the invention, the panels are fixed to each other by welding, gluing, melting and/or fusing.  
      In accordance with a further feature of the invention, additional panels having the slot and tab connectivity are added for forming a self-contained bullet-resistant structure. Such a structure is used for protecting an automobile, building, other vehicles, etc.  
      In accordance with another feature of the invention, the opening may take many different types of shapes such as rectangular shapes, square shapes, slot shapes, oval shapes, circular shapes and triangular shapes. The critical feature being that the shape must be conducive to the fusing process. The fusing may be performed only on one side of the first and second panels. Alternatively, the fusing is performed on both sides of the first and second panels. Contrary to the prior art, the ability to fuse the panels in multiple areas provides increased strength. Ideally, the tabs and slots take up less than 50% of the width of the panel and preferably less than 35%. As the spacing between the slots increases, the change to the mechanical properties of the panels decreases. However, the degree of spacing is also limited by the desired structural integrity.  
      In accordance with another further feature of the invention, the edges, margins or perimeter of the panels are shaped to form a form-locking connection when the edges overlap each other. Because of the shaped edging, changes to the mechanical properties of a panel in a given area is limited as the direction of the fusing, welding, gluing, etc. changes following the pattern of the shaped edge. In this manner, additional panels may be added and connected to each other by either the slot and tab technique or by form-locking connections in dependence on how the panels are interconnected.  
      Ideally, the panels are formed of metals, plastics, glass, composites and acrylic resins.  
      In accordance with a concomitant feature of the invention, the edges have a square wave shape, a dove-tail shape, and/or a tongue and groove type shape. The critical features are that a form-locking connection is formed and that a direction of the shaped edges changes as one traverses the panel so that a fusing line is not straight.  
      Other features which are considered as characteristic for the invention are set forth in the appended claims.  
      Although the invention is illustrated and described herein as embodied in a method of connecting rigid bodies and a rigid body, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
      The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagrammatic, exploded, perspective view of two panels to be connected according to the invention;  
       FIG. 2  is a diagrammatic, perspective view after the connection of the two panels;  
       FIG. 3  is a diagrammatic illustration of the interconnection of three panels according to the invention; and  
       FIG. 4  is a diagrammatic illustration equivalent to  FIG. 3  but highlights a second panel for better comprehension.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the figures of the drawings in detail and first, particularly to  FIG. 1 , thereof, there is shown a first armored panel  1  having a slot  2 . A second armored panel  3  has a protrusion or tab  4  that has been precisely cut to fit into the slot  2 . The invention teaches a method of interlocking and mechanically fixing the panels  1 ,  3  to each other by use of the precision cut tab  4  and the slot  2 . The tab  4  of the second armored panel  3  is inserted into the slot  2  of the first armored panel  1 . Once the tab  4  is inserted into the slot  2 , the second armored panel  3  has mechanical resistance to stresses from every direction but an insertion direction  5  defined by a main axis of the slot  2 . Analogously, the first armored panel  1  has the same stress properties.  
      Because of the assembly method, the mounted panels  1 ,  3  have significant resistance to the main stress points. The added strength needed to withstand cycles of vibration is obtained by fusing completely or partially the inserted tab  4  with the receiving slot  2 . Since an area  6  to be fused is a limited area defined by the slot  2 , modification of the mechanical properties of the first and second panels  1 ,  3  is limited in the worst case to the area  6 . The tab  4  can be fused to the slot  2  by gluing, welding, melting, etc. The fusing method of course is dependent on the material(s) of the panels  1 ,  3  (e.g. metal, glass, acrylic resin, polycarbonate, plastics, etc.) and on the use of the panels. It is noted that the fusing can be done on both sides of the panel if desired and is not restricted to one side or the other side. It is noted that the panels shown in  FIGS. 1 and 2  are exaggerated in the sense that the tab  4  and slot  2  are shown as taking up a good portion of the panels  1 ,  3 . In reality, and as better shown in  FIGS. 3 and 4 , the area necessary for the slots and tabs is small.  
      In addition, the absence of extra parts, such as brackets, to assemble the armored assembly formed of the panels  1 ,  3  ensures a minimum weight and reduces the chances of system failure (e.g. less parts).  
      In  FIG. 3 , three panels  11 ,  12 ,  13  are assembled according to the invention. The third panel  13  is connected to the first panel  11  using the slot and tab technique taught in regards to  FIGS. 1 and 2 . It can be seen from  FIG. 3  that the slots  2  and tabs  4  require a small surface area.  FIG. 4  is equivalent to  FIG. 3  with the exception that panel  13  is shown colored for better identification.  
      All of the panels  11 ,  12 , and  13  may additionally be formed with intricate edging  14 . More specifically, the edges have a dovetail or square wave type interconnection. When the two panels  11 ,  12  are place next to each other, the edgings  14  interlock with each other. The edgings can then be fused to each other by welding, melting or an adhesive, depending on the material forming the panels  11 ,  12 ,  13 . Like in the first embodiment, the edging  14  provides resistance in the main stress directions and can be further connected by fusing for absorbing vibration forces.  
      In  FIGS. 3 and 4  the edgings have a square wave shape. However, the edging can have any interlocking type shape such as dovetail shaping. The critical feature is that a form-locking connection is formed between the panels  11 ,  12 ,  13 . A form-locking connection is one that connects two elements together due to the shape of the elements themselves, as is opposed to a force-locking connection, which locks the elements together by a force external to the elements. For example a nut and bolt holding two elements together is a force-locking connection because of the external force provided by the nut and bolt. In contrast, a ball and socket are held together because the shapes of the ball and socket interconnect with each other and provide the connection without the application of an external force.