You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
   Stand alone safe boxes (also known simply as “safes”) that protect documents, currency, and valuables from fire and theft are now common in most businesses and many homes as well. Safes typically are constructed of a thick metal plates that form an inner compartment for housing the valuables. A door provides access to the inner compartment and a locking mechanism secures the door to the housing to prevent unauthorized entry into the safe interior. The locking mechanism is typically retaining rods that project from the door along inner surfaces into apertures on adjoining surfaces or vice versa. The rods may be maneuvered mechanically, hydraulically, electrically, or by other means, but are traditionally policed by a security mechanism built into the safe door. The security mechanism may be triggered by a numeric or alphanumeric code, a magnetic strip, a simple key, or any other means for storing a code or combination. The triggering device, such as a key or combination, permits the retaining rods to be withdrawn from the outside of the safe via a handle, thereby allowing access to the safe&#39;s interior. Safes come in many sizes and shapes, including floor safes, wall safes, stand-alone safes, and variations thereof. 
   One essential feature of a safe for many businesses and home security purposes is that the safe be capable of protecting its contents in the event of a fire. Because of the intense heat generated in a home or business fire, however, the specifications required to certify a safe for an hour in a standard fire are rigorous and tend to yield safes constructed of steel or lead to withstand the high temperatures. Safes tend to resemble thick-walled boxes of limited physical appeal as function dictates design over form. The thick walls are needed, however, to protect the contents of the safe although this also led to heavy, unwieldy device. The weight characteristics of many safes limited the practical size that these safes could reasonably be constructed for home and small business use since these devices may need to be moved from time to time. Because consumers are always looking for bigger and lighter safes having a more pleasing appearance, the prior art did not satisfy customer demand to its fullest extent. 
   One of the most important feature of a safe that customers look for is its resistance to break-in. Because valuables and other important documents are traditionally stored in safes, they are always targets for thieves who try to pilfer the safe&#39;s contents. The very nature of the safe&#39;s construction, namely five walls and a door, emphasize the achilles heel of most safes is the juncture of the door with the adjoining walls. In particular, a would be thief who is without the access code required to open the safe without disabling it will tend not to attempt to penetrate the fixed walls. Rather, access can most easily be obtained by disabling an exposed hinge or coupling that connects the safe door to the housing. Because hinges are outside the safe and can be mechanically, chemically, or thermally disabled, the hinge is the focus of most safe break-ins. This is frustrating to safe owners and builders, who take great measures to provide sturdy, impenetrable walls and yet the strongest of safes can be defeated by simply disengaging the associated hinge member. 
   Unfortunately, in traditional safe design the hinge is positioned on the exterior of the safe and therefore exposed to mechanical or blunt force that can damage the hinge. In this way, thieves can often defeat the safe&#39;s theft protection characteristics by attacking the hinge which in turn allows the thief to gain access to the contents of the safe. The exposure of the safe door hinge prevents most prior art safes from being completely effective against break-in. The present inventor sought to eliminate the aforementioned shortcomings by using a unique plastic safe design that includes a concealed hinge and therefore resists exposure to break-in via the hinge-housing coupling. 
   SUMMARY OF THE INVENTION 
   The present invention is a safe constructed of a plastic such as acrylonitrile butadiene styrene (ABS) forming a housing that includes a left and right wall, a back wall, a top and bottom wall, and a pivoting door. The pivoting door is mounted to the housing an integral hinge housing that shields the hinge mechanism from would-be thieves. The hinge housing is formed as part of the safe door and includes first and second intersecting planar surfaces forming the exterior portion of the safe hinge, said planar surfaces are parallel and co-planar with the front surfaces of the pivoting door and right wall, respectively, to form a substantially uninterrupted outer surface of the safe. Opposite the first and second intersecting surfaces, the hinge may be formed with a cylindrical surface extending substantially along an arc between the first and second planar surfaces. The first and second planar surfaces and the cooperating cylindrical surface enclose spring loaded rods that extend from the hinge housing so as to be received by designated holes on the inside of the safe to retain the safe door and permit relative swinging of the door between an open and closed position. 
   In a first preferred embodiment of the safe, the safe includes a rubber gasket that seals the safe from water and moisture. The need for a water resistance is particularly important in the event of fire, since water may be sprayed on or near the safe to extinguish the fire. In said first preferred embodiment the safe is UL certified to one hour fire resistance, class 350. The safe may include either mechanical or electrical security controls to operate and regulate the safe. 
   Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features of the invention 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevated perspective view of a first preferred embodiment of the present invention; 
       FIG. 2  is an elevated perspective view of the first preferred embodiment of the present invention with the protective cover up and the handle actuated; 
       FIG. 3  is an elevated perspective view of the embodiment of  FIG. 1  with the door ajar exposing the locking mechanism; 
       FIG. 4  is a side view of the embodiment of  FIG. 1  with the door open and extending ninety degrees from the opening of the safe; 
       FIG. 5  is a front view of the embodiment of  FIG. 1  showing the interior and the inner surface of the hinge element; 
       FIG. 6  is a cross-sectional view of the embodiment of  FIG. 1  taken along line  6 - 6 ; 
       FIG. 7  is a cross-sectional view of the embodiment of  FIG. 1  taken along line  7 - 7 ; 
       FIG. 8  is an elevated, perspective view partially in shadow of the embodiment of  FIG. 1  showing the connection of the safe door to the housing; 
       FIG. 9  is an enlarged, elevated view of the hinge element of the embodiment of  FIG. 1  with the door partially open; and 
       FIG. 10  is another enlarged, elevated view of the hinge element of the embodiment of  FIG. 1  from the inside with the door partially open. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   For a better understanding of the present invention together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above described drawings.  FIGS. 1-3  illustrate a first embodiment of the present invention characterized by a cubic, stand alone plastic waterproof safe  10  having a top wall  12 , a bottom wall  14 , a left wall  16 , a right wall  18 , a back wall  20 , and a swinging front door  22 . The left wall  16 , top wall  12 , right wall  18 , and bottom wall  14  form at respective front edges an opening  21  into the compartment  24 . The opening  21  is bordered by a continuous trim  23  that spans the length of the top, left, and right walls, and abuts the swinging front door  22  at a location  25  vertically spaced from the top and bottom walls. 
   The safe  10  is provided with a security mechanism  26  for gaining entry to the safe&#39;s interior. The security mechanism  26  can be an electronic touch-pad  27  having push buttons  28  coupled to pressure sensitive switches  29  behind said push buttons  28 . The pressure sensitive switches  29  are connected to electrical relays and wires that connect the switches to a circuit board  100 , and allow a user to enter a numeric or alphanumeric code by pressing a sequence of push buttons on the touch pad  27  having a character designation on the front face. The sequence of buttons can be stored in the read only memory (ROM) of the circuit board  100  and compared with a predetermined access code, and the circuit board  100  sends a signal to an actuator  101  to disengage the retaining rods  38  and unlock the front door  22  if the entered code matches the predetermined access code. Alternately, a manual combination lock can be used. An example of a touch pad actuated safe is Sisco&#39;s Honeywell Safe Model Number 2077D offered by the assignee of the present invention. 
   The typical manual combination lock has a combination dial that is attached to a spindle. Inside the lock, the spindle runs through several wheels and a drive cam. The number of wheels in a wheel pack is determined by how many numbers are in the combination—one wheel for each number. When you turn the dial, the spindle turns the drive cam. As the cam turns, drive pins make contact with a small tab on a wheel fly. Each wheel has a wheel fly on each of its sides. A drive pin spins the first wheel until it makes contact with the wheel adjacent to it, which continues until all the wheels are spinning. Each wheel on the spindle has a notch cut into it, and when the right combination is dialed all the wheels and their notches line up perfectly. A small metal bar attached to a lever, called a “fence”, prevents the safe door from being opened without the combination being dialed. It does this by resting on the wheels and blocking the path of the bolt that secures the safe door. When all the wheels line up, their notches align to form a gap. In a safe the fence rests just above the wheels and falls into a gap under the force of its own weight. With the fence gone, the bolt can slide freely past and the safe can be opened. An example of a combination safe is Sisco&#39;s Honeywell Safe Model Number 2054. There are other known security mechanisms that can operate with the safe of the present invention to permit access to the safe&#39;s interior without departing from the scope of the present invention, including scan and digital biometric security devices. 
     FIG. 1  shows the touchpad  27  with push buttons  28  arranged in the standard telephone key pad arrangement. The safe  10  is also provided with a pivoting plastic dust cap  32  that pivots under the influence of gravity down over the touchpad  27  to prevent dust and dirt from gathering in the recesses of the push button gaps. The dust cap  32  can be rotated upward and out of the way when a combination is entered on the touchpad  27 . The safe  10  further includes a handle  36  that opens the safe  10  once the security mechanism has been actuated as is known in the art. The handle  36  is preferably a lever that rotates only after the security mechanism has determined that the correct access code has been entered. Of course, the handle  36  can take many forms and the particular shape or configuration shown in the drawings plays no part of the present invention. 
   Rods  38  extending from the swinging front door  22  into reinforced recesses  40  in the left wall  16  and the right wall  18  to secure the door  22  in a closed position are retracted by a lateral movement of the handle  36 .  FIG. 2  illustrates the flip up position of the dust cap  32  and the actuated position of the handle  36 .  FIGS. 3 and 9  illustrate the position of the rods  38  projecting from the side of the door  22  and further show the location of the reinforced recesses  40  in the inner surface of the side walls  16 , 18  of the safe. The mechanism by which the rods are extended and retracted into the adjacent walls of the safe to secure the safe door closed are well known in the field and its description is omitted herein for the sake of brevity. 
     FIG. 3  illustrates the profile of the door  22  and the complementary shape of the entrance  21  of the safe  10  formed by the trim  23  and the radially inwardly formed shoulder  46 , which mates with the recessed rear peripheral surface  48  of the front door  22 . In a similar fashion, a horizontally directed first inner step  50  on the door cooperates with a complementary rectangular recess  52  in the entrance to the safe interior. A rubber seal  58  (shown in  FIG. 6 ) is compressed against the rectangular recess  52  of the entrance of the safe to create a water proof seal and smoke barrier between the safe door  22  and the peripheral surfaces surrounding the entrance to the safe interior to protect the contests of the safe from water and smoke damage. The inner surface of the door  22  is provided with a pocket  105  for storing papers and includes several hook members  106  for hanging keys or other objects. On the upper surface of the door  22  is a compartment  108  for housing batteries to power the touchpad  27  in the electronic versions of the present embodiment. Retaining rods  38  are clearly shown in  FIG. 3  in their extended position, but said rods are normally retracted when the safe door is open and extended into holes  40  when the safe door is closed to lock the safe from the inside. 
     FIGS. 1 ,  4  and  5  illustrate the safe door  22  in both the open and closed positions and the function of the hinge housing  62 . The right wall  18  of the safe  10  is formed with upper and lower forward facing projections  72  having opposed parallel inwardly facing surfaces spaced apart by a gap, and front faces defining a common plane coincident with the plane of the safe door  22  when the door is in a closed position. The door  22  is integrally formed with a laterally extending hinge column  62  sized to fit into and be retained with said gap ‘G’ defined by said inwardly facing surfaces  77  on said forward facing projections  72 . The hinge column  62  includes an inner surface  66  (see  FIG. 10 ) having a circular profile along an arc between the juncture of the hinge column  62  with the inner surface of the door  22 , and the outer planar surface  70   b . When the door  22  is swung open the inner surface  66  becomes increasingly exposed and the cylindrical surface ensures that no edges or protrusions extend beyond the radius of the cylindrical portion during the initial opening of the door until the door clears a ninety degree position. This is preferable so that the door will open smoothly without catching or knocking anything on the interior of the safe. Further opening of the door  22  beyond the ninety degree position results in the outer planar surface  70   b  coming into view from the perspective of the inside of the safe as shown in  FIG. 10 . 
   Referring back to  FIG. 1 , the exposed outer surfaces  70   a , 70   b  of the hinge housing  62  is formed with first and second flat faces joined at a right angle to coincide with the exterior surfaces of the vertically extending end portions  72  of the right wall so that there is virtually no discontinuity between the door&#39;s front surface and the outer surface of the right wall  18  as seen in  FIG. 1 . This, along with the integral formation of the hinge housing with the door  22 , enables the hinge housing to completely conceal within the safe the pivot support structure so that no portion of the hinge is exposed when the safe is closed. In  FIG. 4  with the door opened 90°, the surface  70   a  is flush with the right side wall  18  forming a smooth, uninterrupted surface from the door  22  to the side wall  18 . In this manner, all aspects of the hinge are seamlessly concealed and confined to the footprint of the safe with no portion of the hinge extending beyond either the plane defined by the front surface of the door or the plane defined by the outer surface of the side wall. 
     FIG. 5  further illustrates the inner face  31  of the left and right walls that include grooves  42  formed by rectangular projections  45  that receive a shelf  44  similar to an oven rack in an oven, where the shelf  44  can be moved to different elevations within the safe by sliding out the shelf and reinserting the shelf into a new groove  42 . Additional shelves can be added as needed by the user. 
     FIGS. 6 and 7  are respective cross sectional views of the door  22 . In  FIG. 6 , the key pad is protected by the hinged dust cover that rotates about lynch pin  74  to expose the push buttons  28 . The rubber seal  58  is clearly shown as secured inside the groove formed by the recess in the door&#39;s profile. The door  22  includes an interior compartment  107  that is filled with a foam insulation  109 , where a wire mesh divider  111  runs through the middle plane of the door  22 . A data port  113  may also be located on or adjacent to the key pad  27  that links with the security mechanism and can be used to override the touch pad security sequence or the manual combination sequence. That is, should the lock combination become lost or forgotten, the circuit board  100  can be accessed through the data port  113  and the safe opened or reprogrammed with a new code. With respect to  FIG. 7 , the vertical column that forms the housing of the hidden hinge is shown in profile depicting the first surface  66  of semi-cylindrical contour, and the opposite surfaces formed by two adjacent faces  70   a,b , the first face  70   a  parallel and coincident with the outer surface  119  of the door  22  and the second face  70   b  parallel and coincident with the outer surface of the right wall  18 . Extending vertically from the upper and lower projections  72  are spring actuated pivot rods  120  that are compressed while the hinge column  62  is positioned in the gap ‘G’, and then released to register in collinear bores (see  FIG. 8 ) in the respective upper and lower surfaces of the hinge housing so as to allow the door  22  to be mounted on the housing and swing open and closed. 
     FIGS. 9 and 10  are an enlarged views of the inner surface of the hinge as the door  22  begins to open. The surface  70   b  rotates toward the safe&#39;s interior as the door swings open, until it reappears (see  FIG. 10 ) on the safe&#39;s interior as the door opens up completely.  FIG. 9  illustrates two seals or washers  139 ,  141  between the hinge column and the portions  72  of the right wall  18  that facilitate the swinging of the door without binding. A mechanical sensor  145  can also be included that compresses when the safe door  22  is closed, signaling the circuit board of the status of the door. 
   An important feature of the present invention is that the safe can be formed of a heat resistant plastic such as, for example, an acrylonitrile-butadiene-styrene (ABS) resin produced by continuous mass (or bulk), suspension or emulsion polymerization. ABS resins are composed of over 50 percent styrene and varying amounts of butadiene and acrylonitrile. The use of a heat resistant plastic such as an ABS resin significantly reduces the weight of the safe without sacrificing significant strength or heat capacity. In a preferred embodiment, the ABS resin is ABS Porene GA850, a high impact high gloss ABS with superior heat and melt characteristics and desirable strength under both nominal and high temperature environments. The following chart shows the characteristics of ABS Porene GA850. 
   
     
       
             
           
             
             
             
             
           
             
             
             
             
           
         
             
                 
             
             
               Article I. TPI Porene ® Grade ABS-GA850 High Impact ABS Resin 
             
             
               Subcategory: ABS Polymer; Polymer; Thermoplastic 
             
           
        
         
             
                 
               Metric 
               English 
               Comments 
             
             
                 
                 
             
           
        
         
             
               Physical Properties 
                 
                 
                 
             
             
               Density 
               1.05 g/cc 
               0.0379 lb/in 3   
               ASTM D792 
             
             
               Melt Flow 
               20 g/10 min 
               20 g/10 min 
               220° C./10 kg 
             
             
               Mechanical Properties 
             
             
               Hardness, Rockwell R 
               118 
               118 
               ASTM D785 
             
             
               Tensile Strength, Yield 
               51.7 MPa 
               7500 psi 
               at ⅛ in (3.2 mm). 
             
             
               Flexural Modulus 
               2.34 GPa 
               339 ksi 
               at ⅛ in (3.2 mm). 
             
             
               Flexural Yield Strength 
               70.3 MPa 
               10200 psi 
               at ⅛ in (3.2 mm). 
             
             
               Izod Impact, Notched 
               2.67 J/cm 
               5 ft-lb/in 
               at 6.4 mm (¼ in). 
             
             
               Izod Impact, Notched 
               2.99 J/cm 
               5.6 ft-lb/in 
               at 3.2 mm (⅛ in). 
             
             
               Thermal Properties 
             
             
               Maximum Service Temperature, Air 
               87° C. 
               189° F. 
               Deflection Temp 
             
             
               Deflection Temperature at 0.46 MPa (66 psi) 
               96° C. 
               205° F. 
               ASTM D648 
             
             
               Deflection Temperature at 1.8 MPa (264 psi) 
               87° C. 
               189° F. 
               ASTM D648 
             
             
               Flammability, UL94* 
               HB 
               HB 
                1/16 in (1.6 mm) 
             
             
               Flammability, UL94* 
               HB 
               HB 
               ⅛ in (3.2 mm) 
             
             
               Processing Properties 
             
             
               Rear Barrel Temperature 
               193° C. 
               380° F. 
             
             
               Middle Barrel Temperature 
               216° C. 
               420° F. 
             
             
               Front Barrel Temperature 
               232° C. 
               450° F. 
             
             
               Melt Temperature 
               218-260° C. 
               425-500° F. 
               Nozzle temp not greater than 
             
             
                 
                 
                 
               stock 
             
             
               Mold Temperature 
               48.9-65.6° C. 
               120-150° F. 
             
             
               Drying Temperature 
               87.8-93.3° C. 
               190-200° F. 
             
             
               Dry Time 
               2-24 hour 
               2-24 hour 
             
             
               Injection Pressure 
               68.9-82.7 MPa 
               10000-12000 psi 
             
             
               Back Pressure 
               0.689 MPa 
               100 psi 
             
             
               Screw Speed 
               50-60 rpm 
               50-60 rpm 
             
             
                 
             
           
        
       
     
   
   Using the aforementioned ABS plastic, the present invention has achieved Underwriters Laboratories certification for class 350—1 Hour Fire Resistance. The present design has also been found to prevent the introduction of water even after being submerged for twelve hours in a tank. 
   The features of the present invention demonstrate a light weight fire proof and water proof safe that incorporates a hinge mechanism substantially concealed and shielded from access while the safe is closed. The nature of the hidden hinge prevents tampering or vandalism to the hinge. The insulation in the plastic compartments that form the respective side, top, bottom, and front and rear walls protect the contents of the safe from heat damage even if the exterior of the safe suffers damage. While the drawings and description of the safe feature specific embodiments, the scope of the present invention is not intended to be limited by said embodiments, but rather one of ordinary skill in the art will readily appreciate modifications to the disclosed embodiments that should be included in the scope of the invention. Accordingly, the metes and bounds of the invention are properly governed in accordance with the foregoing description but limited only by the ordinary words and terms of the appended claims.

Summary:
A plastic safe box has a housing formed of connected panels defining an interior space, and a pivoting door supported on a hinge member integrally formed with said pivoting door. The hinge member receives a support rod mounted inside the safe such that the hinge member is not exposed when the safe is closed. The hinge member is shaped to coincide with the adjoining side panel and door outer surfaces to hide the hinge and conceal the operational hinge components. The hinge member further includes a rounded inner surface that emerges internally as the safe door opens, where the rounded surface is circular with a center coincident with the support rod such that the hinge member follows a circular path as the safe door opens.