Patent Publication Number: US-6711922-B1

Title: Mechanism of a combination lock for beginning and ending combination-changing operation

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     The present invention relates to a mechanism for beginning and ending the unlocking numeral-combination changing operation of a combination lock, more particularly one, which, while being moved from the position allowing the combination-changing action back to the normal position, cannot cause unwanted rotational movement of the dials, thus preventing accidental change of the combination after it has been changed to a predetermined one. 
     2. Brief Description of the Prior Art 
     Referring to FIG. 12, a conventional changeable combination lock includes: 
     a lock bar  81 , which has a cone-shaped head, a lock rod  813  joined to the head; the cone-shaped head having a trench  812 ; the lock rod  813  having spaced apart teeth  8131 , and spaces  8132  between the teeth  8131 ; 
     a spindle  84 , which has a convex edge  841  at a front end, a channel  842  having an upper opening, and flat sides on a bottom and an upper side of a rear end thereof, on which a fixing hole  843  is formed; 
     a thimble  85 , which has a round disk, and an annular wall around the disk; the disk having a through hole  853 , two protruding blocks  851 ,  851  at opposite portions of the inward side thereof, and a stopping block  852  on the outward side thereof; 
     several dials  87 , each of which has numerals  8705  spaced out on an outer side, an inserting hole  8701  on the middle, spaced teeth  8702  projecting towards the center thereof, spaced convexly curved surfaces  8704 , and withholding spaces  8703  between the teeth  8702 ; 
     several tooth dishes  871 , each of which has an inserting hole  8711 , a gap  8712 , and spaced apart convex teeth  8713  on an outward side thereof; 
     a spring  844  for biasing the tooth dishes  871  to an engaged position where the convex teeth  8713  engage the teeth  8704  of corresponding dials  87  so that the tooth dishes  871  will be turned together with corresponding dials  87 ; 
     a barrel  83 , which has a cone-shape, a cavity  831 , a hole  832 , a pin hole  833  in communication with the hole  832 , and a trench  834 ; the hole  832  having flat upper and lower sides; 
     a setting push ring  86 , which has a gap  861 , and protruding edges  862  at two opposite portions of an outward side thereof; each of the protruding edges  862  having a slope  8621 ; and, 
     holding elements  88 , each of which has a gap  8801 , and two opposite engaging protrusions  8802 ; the holding elements  88  being used for holding respective sliding elements  881  in position, each of which has a gap  8811 , two recesses at two opposite portions of an outward side thereof, 
     the spindle  84  being passed through the thimble  85 , the setting push ring  86 , a first one of the dials  87 , a first one of the tooth dishes  871 , a first one of the holding elements  88 , a first one of the sliding elements  881 , a second one of the dials  87 , a second one of the tooth dishes  871  and so on, and being finally passed through the spring  844  and inserted into the hole  832  of the barrel  83 ; the protruding blocks  851  of the thimble  85  being pressed against the slopes  8621  of the setting push ring  86 ; the teeth  8713  of the tooth dishes  871  being engaged with the teeth  8702  of respective dials  87 ; a pin  835  being inserted into the pin hole  833 , and the fixing hole  843  to securely join the spindle  84  to the barrel  83 . 
     Thus, the lock bar  81  is locked with the tooth dishes  871 , and incapable of separating from the spindle  84  when the dials  87  are turned off the unlocking numeral combination. 
     To change the unlocking numeral combination, first the thimble  85  is turned so that the protruding blocks  851  of the thimble  85  slide on the slopes  8621  of the setting push ring  86  to push the setting push ring  86 , and in turn, the tooth dishes  871  are disengaged from the respective dials  87 . Then, the dials  87  are turned so that orientation of the dials  87  relative to the gaps  8712  of respective tooth dishes  871  is changed. Finally, the thimble  85  is turned back to the original position for allowing the spring  844  to force the tooth dishes  871  to engage the respective dials  87  again. 
     Referring to FIG. 3, another conventional changeable combination lock is substantially like the above one except having folded elastic wires  985 , and holding elements  98  instead of the sliding elements  881  and the holding elements  88 ; the folded elastic wires  985  are held in position by means of the holding elements  98 . 
     Both the conventional changeable combination locks are found to have a disadvantage that when the thimble  85  is being moved back to the normal position after the numeral combination-changing action, undesired rotational movement of the dials are prone to be caused accidentally. In other words, accidental change of the combination is likely to happen after the combination has been changed to a predetermined one, causing the user a lot of inconvenience. 
     SUMMARY OF THE INVENTION 
     It is a main object of the present invention to provide a mechanism for beginning and ending the unlocking-numeral combination-changing operation, which is structured such that movement thereof cannot cause rotational movement of the dials accidentally. 
     The present mechanism includes a pressing block fitted to the front end of a spindle of a changeable combination lock and associated with a pad. The pad has posts contacting a most front one of several spring-loaded tooth dishes, which separably engage respective dials each having numerals spaced on the outer side. 
     The pressing block is pressed towards a rear end of the spindle so that the posts force all the tooth dishes to move rearwards to disengage respective dials; thus, the dials can be turned relative to the tooth dishes for changing the unlocking numeral combination to a new one; the pressing block is pressed slightly down right after being pushed rearwards so that it can be held in position allowing the tooth dishes to stay disengaged from respective dials. When the combination changing operation is finished, the pressing block is pushed back to the original position for the tooth dishes to engage respective dials again. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be better understood by reference to the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of a combination lock according to the present invention, 
     FIG. 2 is a cross-sectional view of the combination lock according to the present invention, 
     FIG. 3 is a front view of the combination changing mechanism of a combination lock according to the present invention, 
     FIG. 4 is a partial vertical view of the combination changing mechanism of a combination lock according to the present invention, 
     FIG. 5 is a front view of an inner part of the combination lock according to the present invention, 
     FIG. 6 is another front view of an inner part of the combination lock according to the present invention, 
     FIG. 7 is another cross-sectional view of the combination lock according to the present invention, 
     FIG. 8 is another front view of the combination changing mechanism according to the present invention, 
     FIG. 9 is another partial vertical view of the combination changing mechanism according to the present invention, 
     FIG. 10 is another front view of an inner part of the combination lock according to the present invention, 
     FIG. 11 is yet another front view of an inner part of the combination lock according to the present invention, 
     FIG. 12 is an exploded perspective view of the first combination lock as described in the Background; and, 
     FIG. 13 is an exploded perspective view of the second combination lock as described in the Background. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the combination lock of the present invention includes a lock bar  7 , several dials  3 , several tooth dishes  4 , a spring  6 , and a lock barrel  1 , which have either the same shape or the same function as the lock bar  81 , the dials  87 , the tooth dishes  871 , the spring  844 , the barrel  83  of the first conventional combination lock described in the Background respectively; the lock bar  7  has a connecting portion  73  for a steel wire (not shown) to be connected to, a lock rod  71 , and several teeth  72  spaced along the lock rod  71 ; each of the dials  3  has numerals spaced out on an outer side, an inserting hole  31  on the middle, spaced teeth  32  projecting towards the center thereof, spaced convexly curved surfaces  34 , and withholding spaces  33  between the teeth  32 ; each of the tooth dishes  4  has a through hole  43 , and a tooth  41  projecting out from the edge; the barrel  1  has a connecting cavity  11 , a connecting portion  12  for the other end of the steel wire to be connected to, and a pin hole  13 . 
     The present combination lock also has several combinations of folded elastic wire  53  and holding element  5 , which are the same as the combinations of folded elastic wire  985  and holding element  98  of the second conventional combination lock of the Background; each of the holding elements  5  has a through hole  52 , and a holding trench  54 , on which a respective folded elastic wire  53  is held in position. 
     The combination lock is further equipped with a mechanism for beginning and ending a combination-changing operation according to the present invention, which includes: 
     spindle  2 , which includes a holding room  21  at a front end portion, a holding slot  25 , several locating gaps  212  in front of the holding room  21 , through holes  213  behind the holding room  21 , a cavity  214  at a bottom of the front end, a fixing hole  26  at a rear end, and spaced protrusions  27 ; 
     a pad  22 , which has a through hole  221 , and posts  222  sticking out from a rear side to be passed through the through holes  213  of the spindle  2 ; 
     a pressing block  23 , which has a through hole  231 , and locating protrusions  232  on a front side thereof to be separably engaged with the locating gaps  212 ; and, 
     a thimble  24 , which has a protrusion  241  on an inner edge. 
     To assemble the present lock, the spindle  2  is passed through a first one of the dials  3 , a first one of the tooth dishes  4 , a first one of the holding elements  5 , a second one of the dials  3 , a second one of the tooth dishes  4  and so on, and is finally passed through the spring  6  and inserted into the hole  11  of the barrel  1 ; the spring  6  biasing the tooth dishes  4  towards the front end of the spindle  2  so that the teeth  41  of the tooth dishes  4  are engaged with the teeth  32  of respective dials  3 ; a pin  14  being inserted into both the pin hole  13  of the barrel  1  and the fixing hole  26  of the spindle  2  to securely join the spindle  2  to the barrel  1 . Then, the posts  222  of the pad  22  are passed through respective through holes  213  of the spindle  2  to come into contact with a most front one of the tooth dishes  4 , and the pressing block  23  is positioned in the holding room  21  of the spindle  2  and over the pad  22 . Finally, the thimble  24  is fitted around the front end portion of the spindle  2  with the protrusion  241  being engaged with the cavity  214  of the spindle  2  so that the pressing block  23  is confined in the holding room  21  and the thimble  24  can&#39;t be turned relative to the spindle  2 . 
     Referring to FIGS. 2 to  6 , when the pressing block  23  is not pressed inwardly of the spindle  2 , the spring  6  forces the tooth dishes  4  to engage the withholding holes  33  of corresponding dials  3  at the convex teeth  41  of the tooth dishes  4  so that the tooth dishes  4  will turn together with corresponding dials  3 . 
     The pressing block  23  has to be first pressed inwardly of the spindle  2  for beginning the combination changing operation. Referring to FIGS. 7 to  11 , when the pressing block  23  is pressed inwardly of the spindle  2 , the locating projections  232  of the pressing blocks  23  will be separated from the locating gaps  212  of the spindle  2 , and the posts  222  of the pad  22  will act against the spring  6  to cause the tooth dishes  4  to move towards the rear end of the spindle  2  so that the convex teeth  41  separate the withholding holes  33  of corresponding dials  3 . At the same time, the pressing block  23  is made to slide down for a short distance, and then released so that the locating projections  232  are pressed against the those portions of the front end of the spindle  2  that are adjacent to the locating gaps  212 , as shown in FIG. 8; thus, the tooth dishes  4  will stay disengaged from respective dials  3 , and the users doesn&#39;t have to keep pressing the block  23  while they are turning the dials  3  relative to the tooth dishes  4  to change the combination of unlocking numerals. 
     After the combination of unlocking numerals has been changed to a new one, the pressing block  23  is pushed up so that the locating projections  232  are made to snap back into the locating gaps  212  with the spring  6 , which also makes the tooth dishes  4  engage respective dials  3  at the same time so that the tooth dishes  4  can be turned together with respective dials  3 , i.e. the combination lock can be used normally. To use the combination lock, the toothed lock rod  71  of the lock bar  7  is inserted into the holding slot  25 , and the dials  3  are turned so that other people can&#39;t find the unlocking numeral combination. 
     From the above description, it can be easily understood that the present mechanism for beginning and ending a combination-changing operation is relatively convenient to use as compared with the above conventional ones because only one hand is required for beginning the combination changing operation instead of two. And, the operation of the present mechanism won&#39;t cause accidental rotation of the dials, thus preventing accidental change of the unlocking numeral combination after it has been changed to a new one.