Abstract:
A combination lock includes a core unit, a locking mechanism, and a reset mechanism formed of a guide rod, a sliding plate, a stop rod and a reset member. The sliding plate is downwards to push the locking mechanism to the unlocking position wherein operation buttons pressed subject to the set code. When the locking mechanism lifted to push the reset member of the reset mechanism, the locating rod of the reset member pushes the stop rod away from the rack of the sliding plate, enabling the sliding plate to be returned by a spring member so that the core unit is returned to the initial position for resetting the code.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a combination lock and, more particularly, to a combination lock with a modularized core unit that enables to the user to reset the code without the key, and provides an anti-piracy function.  
           [0003]    2. Description of the Related Art  
           [0004]    Regular commercially available combination locks include electronic pushbutton digits type combination locks and mechanism pushbutton type combination locks. According to conventional designs, the code control mechanism is not a standardized independent unit for use in different locking devices of different functions and shapes. According to the aforesaid two types of combination locks, a reset button is needed to clear error signal or to give an initial working signal. This arrangement is not safety because the code can easily be pirated by other people.  
           [0005]    There is also known a combination lock, which achieves the code control by means of the arrangement of N and S poles of magnetic elements subject to a predetermined order. This design of combination lock is functional. However, opening this design of combination lock requires a specially designed key. This specially designed key is complicated. Further, the user cannot change the code of the key.  
           [0006]    Therefore, it is desirable to provide a combination lock, which eliminates the aforesaid drawbacks.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a combination lock, which enables the user to reset the code when desired. It is another object of the present invention to provide a combination lock, which effectively prevents piracy of the code by other people. According to one aspect of the present invention, the combination lock is comprised of a core unit, a reset mechanism, and a locking mechanism. When the core unit unlocked, the locking mechanism drives the reset mechanism to release the sliding plate of the core unit, enabling the core unit to be turned to the initial state for re-setting the code. According to another aspect of the present invention, the combination lock has a code. If the combination lock is not operated subject to the order of the code, real-code buttons and false-code buttons of the core unit will drive the reset mechanism to work, stopping the sliding plate of the core unit from downward movement or returning the sliding plate to its initial position, and therefore the code entry is destroyed, not able to open the lock.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a side view in section of a combination lock according to the present invention.  
         [0009]    [0009]FIG. 2 is another side view of the combination lock according to the present invention.  
         [0010]    [0010]FIG. 3 is a sectional view showing the action of the core unit according to the present invention (I).  
         [0011]    [0011]FIG. 4 is a sectional view showing the action of the core unit according to the present invention (II).  
         [0012]    [0012]FIG. 5 is a sectional view showing the action of the reset mechanism according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    Referring to FIGS. 1 and 2, a combination lock in accordance with the present invention is shown comprised of a core unit  1 , a reset mechanism  2 , and a locking mechanism  3 .  
         [0014]    The core unit  1  comprises an outer partition plate  11 , an inner partition plate  12 , a push board  13 , real-code buttons  14 , false-code buttons  15 , and a shell  16 . The shell  16  is a substantially C-shaped member having a bottom through hole  161 . The outer partition plate  11  and the inner partition plate  12  are mounted in the shell  16  and joined by posts  111 . A movable security member  112  and a support member  1122  are mounted in between the outer partition plate  11  and the inner partition plate  12 . The push board  13  is disposed at an inner side relative to the inner partition plate  12 , comprising an upright center guide rod  131 , a locating rod  132 , and two locating end flanges  133 . The center guide rod  131  is axially movably inserted through an axle bush  121  in the inner partition plate  12  and an axle bush  113  in the outer partition plate  11 . A return spring  1311  is mounted on the center guide rod  131  and supported between the outer partition plate  11  and the inner partition plate  12 .  
         [0015]    The buttons (real-code buttons  14  and false-code buttons  15 ) are axially movably inserted through (a respective through hole  122  in) the inner partition plate  12  and (a respective through hole in) the outer partition plate  11 , each having an annular groove  1441  around the respective periphery on the middle and coupled to the security member  112 . The security member  112  stops the buttons  14  and  15  from escaping out of the core unit  1 . The outer partition plate  11  and the outside wall of the combination lock have corresponding marks marked thereon by the side of the respective through holes for the buttons  14  and  15 . Each button  14  or  15  comprises an axially extended chamber  141 , a return spring  142  mounted in the chamber  141 , a screw bolt  143  threaded into the chamber  141  and stopped against one end of the return spring  142 . The other end of the return spring  142  extends out of the bottom side of the chamber  141  and fastened to the periphery of the corresponding through hole  122  in the inner partition plate  12  for enabling the respective button  14  or  15  to be moved axially in the corresponding through hole  122 . The screw bolt  143  of the real-code button  14  has a corresponding digit (or letter) marked on the top surface of the head thereof and equiangularly arranged in an order. Each real-code button  14  has a front end terminating in a push rod  144 , which passes through the inner partition plate  12 , and has a beveled push face  1441 . The transverse width of the push rod  144  varies in different directions and is angularly gradually increased subject to the order and positions of the digits (or letters) on the top surface of the head of the screw bolt  143 . The push rod  144  of the false-code button  15  does not have such beveled push face  1441  or the aforesaid features.  
         [0016]    The reset mechanism  2  is installed in the inner side of the inner partition plate  12  inside the shell  16 , comprised of a guide rod  21 , a sliding plate  22 , a return spring  23 , a holder frame  24 , a stop rod  25 , and a reset member  26 . The guide rod  21  is fixedly connected between the two end flanges  133  of the push board  13  of the core unit  1 . The sliding plate  22 , the return spring  23  and the holder frame  24  are respectively mounted on the guide rod  21 . The sliding plate  22  has a rectangular opening  221  and a rack  222  at the bottom side. The holder frame  24  is mounted on the guide rod  21 . The return spring  23  is sleeved onto the guide rod  21  and stopped against the holder frame  24 , which is stopped at a locating ring A at one end of the guide rod  21 . The holder frame  24  has a torsional spring  241  located on the inside. The stop rod  25  is mounted in the holder frame  24  and coupled to the torsional spring  241 , having a bottom stop end  251  curved at an acute angle and engaged with the rack  222  at the bottom side of the sliding plate  22  and a top end  252  connected to a projecting rod  262  at the reset member  26 . A pin F is mounted in the stop rod  25  to secure the stop rod  25  and a spring member E to the holder frame  24 . The reset member  26  is an angled member having a longitudinal sliding slot (not shown) longitudinally disposed on the middle and coupled to the bottom side of the shell  16  by a rivet B, a push portion  261  at one end, an eye lug  265  at the other end, a locating rod  263  riveted to the bottom side of the shell  16 , a tensile spring  264  connected between the eye lug  265  and the locating rod  263 . The projecting rod  262  is located on a middle part of the reset member  26 . A ring handle  17  is coupled to a shaft  171  outside the shell  16 .  
         [0017]    The locking mechanism  3  is fixedly fastened to the bottom side of the shell  16 , comprising a push rod  31 , an actuating rod  32 , a movable stop rod  33 , and a shaft  34 . The push rod  31  and the actuating rod  32  are respectively aimed at a through hole  161  in the shell  16 . The push rod  31  is supported on a spring  311  and forced by the spring  311  against the free end  331  of the movable stop rod  33 . A pivot C pivots the other end of the movable stop rod  33  to the locking mechanism  3 . The movable stop rod  33  has a sloping projection  332  engaged into an annular locating groove  341  around the periphery of the shaft  34 . The shaft  34  has another annular locating groove  342  for the engagement of a locking rod  321 , which has the other end pivoted to one end the actuating rod  32 . The actuating rod  32  has a middle part pivoted to a support rod  322 , and the other end terminating in a press portion  323 , which extends to the through hole  161  of the shell  16 .  
         [0018]    Referring to FIGS.  3 ˜ 5 , the bottom side of the rectangular opening  221  of the sliding plate  22  is disposed below the end of the real-code button  14 . When pressing one real-code buttons  14 , the respective push rod  144  is moved horizontally to force the respective beveled push face  1441  into contact with the periphery of the rectangular opening  221  of the sliding plate  22  and to further push the sliding plate  22  downwards at a distance equal to the tooth pitch of the rack  222  of the sliding plate  22 . When the user pressed the assigned real-code buttons  14  subject to the set code, the sliding plate  22  is moved downwards to extend the rack  222  to the outside of the through hole  161  of the shell  16  and to force the actuating rod  32  of the locking mechanism  3 , thereby causing the locking rod  321  to be lifted from the annular locating groove  342  of the shaft  34  to unlock the locking mechanism  3 .  
         [0019]    When the locking mechanism  3  unlocked, the push rod  31  of the locking mechanism  3  is moved upwards against the push portion  261  of the reset member  26  to lift the reset member  26 , thereby causing the projecting rod  262  to push the top end  252  of the stop rod  25 , and therefore the stop rod  25  is forced to disengage the bottom stop end  251  from the rack  222  of the sliding plate  22 . When the bottom stop end  251  of the stop rod  25  disengaged from the rack  222  of the sliding plate  22 , the return spring  23  immediately returns the sliding plate  22 , and the respective return springs  142  force the respective real-code buttons  14  to their reset position, and therefore the core unit  1  is reset.  
         [0020]    If the buttons  14  and  15  are pressed not subject to the predetermined code, the vertical side D of each pressed button  14  or  15  will push the sliding plate  22  along the guide rod  21  to move the push board  13  horizontally, causing the holder frame  24 , the stop rod  25 , the center guide rod  131 , and the locating rod  132  to be moved with the sliding plate  22  horizontally to force the top end  252  of the stop rod  25  against the projecting rod  262  of the reset member  26 . Therefore, the stop rod  25  is turned clockwise to move the bottom stop end  251  away from the rack  222  of the sliding plate  22 , enabling the return spring  23  to return the sliding plate  22 , i.e., the combination lock is maintained in the locked status.  
         [0021]    The combination lock has an anti-piracy function. The first one of the real-code buttons  14  (the real-code button that is marked with digit “1”) does not provide a re-setting function. However, the other buttons  14  and  15  provide a re-setting function, i.e., the other buttons  14  and  15  can be pressed subject to the predetermined code to unlock the combination lock after having been pressed incorrectly.  
         [0022]    Further, when changing the code, remove the locking mechanism  3  from the shell  16 , than press the extension end  1121  of the movable security member  112  to release the buttons  14  and  15 , and then install the selected real-code buttons  14  in the coded holes in the outer partition plate  11  subject to the selected code and the other buttons  15  in the other holes in the outer partition plate  11 , and then install the locking mechanism  3  in the shell  16  again.  
         [0023]    When the total number of the buttons is 9 and 5 buttons are selected for real-code buttons, more than 150 thousands of code combinations are available. When total 12 buttons are provided and 6 buttons are selected for real-code buttons, more than 650 thousands of code combinations are provided.  
         [0024]    A prototype of combination lock has been constructed with the features of the annexed drawings of FIGS.  1 ˜ 5 . The combination lock functions smoothly to provide all of the features discussed earlier.  
         [0025]    Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.