Patent Publication Number: US-9422745-B2

Title: Safe with nitinol wire locking mechanism

Description:
BACKGROUND OF THE INVENTION 
     Safe boxes (also known as “safes”) are well known in the prior art. They are used primarily to protect documents, currency, jewelry, and other valuables from fire and theft. Stand alone safes are very common in homes and businesses throughout the world. A fire-resistant safe (also known as a “fire safe”) is a type of safe that is designed to protect its contents from high temperatures or actual fire. There are various types of locking mechanisms currently being utilized for safes that incorporate known technologies. 
     Nitinol Wire 
     Nitinol Wire (also known as ‘Muscle Wire’ or ‘Memory Wire’) is a thin strand of a special shape memory alloy composed primarily of Nickel (Ni) and Titanium (Ti). Nitinol Wire will shorten in length after receiving an electrical signal, or heated by other means. Nitinol wire returns to its original length the electrical signal is removed and/or cooled. 
     What is needed is a better safe that allows operation through a user controlled keypad as well as a backup operation via a hand held key. 
     SUMMARY OF THE INVENTION 
     The present invention provides a safe. A safe lid is connected to a safe box via a hinge attachment. The safe is locked shut by utilization of a latch assembly. A Nitinol wire is connected to a latch assembly opening device. The latch assembly opening device is connected to the latch assembly. A user can open the safe by inputting the correct pass code into a keypad. An electrical signal is then transferred to the Nitinol wire causing the Nitinol wire to shorten. The shortening of the Nitinol wire causes the latch assembly opening device to open the latch assembly. In a preferred embodiment a key lock is also configured to control the latch assembly opening device and the key lock may be used as another method to open the safe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a preferred safe. 
         FIG. 2A  shows a top view of a preferred safe. 
         FIG. 2B  shows a front view of a preferred safe. 
         FIGS. 3A-4C  show the internal features of a preferred safe. 
         FIGS. 5A-5E  show illustrate the locking mechanism of a preferred safe. 
         FIGS. 6A-6C  show the function of the key lock. 
         FIG. 7  shows a preferred fire safe. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows digital fire safe  100  having lid  15  and box  14 . Lid  15  is connected to box  14  via hinges  135 . When digital fire safe  100  is closed, the safe is locked by the latch assembly  4 . The safe can only be opened after latch assembly  4  is released from the lid  15 . When emergency key lock  17  is under the lock position, latch assembly  4  can be released automatically by utilizing keypad  113 . As an alternative or in an emergency, safe  100  can be opened by utilizing key lock  17 . Hence, key lock  17  can then be used as a second or backup method for opening the safe. 
     Key pad  113  allows safe  100  to be opened without the use of a key. When the correct passcode is entered via keypad  113  (see also  FIGS. 2A, 2B ), a 3V electrical signal is transmitted from keypad  113  through electrode plates  18  to electrode rods  3  ( FIGS. 2B, 3A ). Electrode plates  18  extend downward through front cover  119  ( FIG. 3A ). The electrical signal passes through electrode plates  18  to electrode rods  3 , which then passes the electrical signal through the positive terminal wire  16  and negative terminal wire  2  to crimps  7 A ( FIG. 5A ) that are attached to Nitinol wires  8  (see also  FIGS. 4A-4B ). When a current passes through Nitinol wire  8 , the length shortens, pulling on rotatable push plates  5  and causing them to turn ( FIG. 5B ). Rotatable push plates  5  function as a latch assembly opening mechanism. As rotatable push plates  5  turn, wheels  6  move upwards, pushing onto the latch buttons  6   b , which activates internal spring mechanism  6   c . Locking tab  33  is then pulled clear of lid  15  thereby releasing latch assembly  4  from lid  15  ( FIGS. 3A-5E ). 
     When Nitinol wire  8  shortens, it pulls on the rotatable push plates  5 . Simultaneously, push rods  9  and  13  push the bottom half of lock levers  11  and  12  to move against the center, causing a tension on lock lever springs  10  ( FIGS. 5B and 3C ). 
     The electrical signal is transmitted for approximately 3 seconds. After 3 seconds, Nitinol wire  8  lengthens and returns back to its original length. At this time, the lock lever springs  10  pull lock levers  11  and  12 . Lock lever springs  10  function as a This action moves push rods  9  and  13  causing the rotatable push plates  5  to turn to their original positions while pulling wheel  6  back to its original position, as shown in  FIG. 5A . 
     Using a key to turn key lock  17  ( FIG. 5C ), the top part of lock levers  11  and  12  is pushed apart by mechanism  17   b  (see also  FIGS. 6A-6C ). This action pulls push rods  9  and  13 , which push wheels  6  to move upwards, pushing onto the latch buttons  6   b , which activates internal spring mechanism  6   c  of latch assembly  4 , releasing it latch assembly  4  from lid  15  ( FIGS. 5A and 4C ). 
     When environmental temperature reaches 75° C., low melt metal rod  1  ( FIGS. 4A, 5A, 5B ) melts and Nitinol wire  8  loses an anchor point, causing it to have no pulling force to push the wheels  6  to push onto latch buttons  6   b  to release the latch assembly  4 . After low melt metal rod  1  has melted, key pad  113  can no longer be used to open the safe. 
     Other Embodiments 
       FIG. 7  shows that safe  100  can be a fireproof safe. For example box  4  includes interior wall  54  and exterior wall  53  with fireproof insulation  55  between. To make safe  100  a fireproof safe, all walls of box  14  and lid  15  include insulation  53  sandwiched between interior and exterior walls. Also, it should be noted that safe  100  can be fabricated from either plastic or metal. 
     Although the above-preferred embodiments have been described with specificity, persons skilled in this art will recognize that many changes to the specific embodiments disclosed above could be made without departing from the spirit of the invention. Therefore, the attached claims and their legal equivalents should determine the scope of the invention.