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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to locks, and more specifically to a pointer padlock that provides a safety burglarproof effect. 
     2. Description of the Related Art 
     Conventional locks generally include a key controlled lock, which needs a correct key to unlock it, and a combination controlled lock, which needs a correct permutation of numbers or symbols to unlock it. 
     When a user would like to buy a lock, the burglarproof effect of the lock is the most important concern for the user. As far as the combination controlled lock is concerned, it can provide better burglarproof effect than the key controlled lock by means of rotating numbered wheels to show the correct permutation of numbers or symbols. However, the conventional combination controlled lock generally has three or four numbered wheels and therefore the permutation of numbers is finite and may be easily unscrambled by someone. If the number of the numbered wheels is increased, the permutation of numbers showed by the numbered wheels will be too complex to be remembered by the user and the structure of the combination controlled lock will be too complicated, limiting the outline design of the combination controlled lock. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished in view of the above-noted circumstances. It is one objective of the present invention to provide a padlock, which has pointers to provide a safety burglarproof effect. 
     To achieve this objective of the present invention, the padlock comprises a housing, a shackle, a retaining device, and at least two pointers. The housing has an accommodation chamber, a first top hole in communication with the accommodation chamber, a second top hole in communication with the accommodation chamber, and a dial mounted on a top side thereof and provided with a plurality of figures. The shackle has a pivoting portion pivotally passing through the first top hole of the housing into the accommodation chamber of the housing and axially movable relative to the housing, and a locking end insertable into the second top hole of the housing. The retaining device is disposed in the accommodation chamber of the housing and has at least two driving wheels for controlling an axial movement of the pivoting portion of the shackle. The pointers are located above the dial of the housing and respectively driven by the driving wheels of the retaining device to point to one of the figures. When both of the pointers point to correct figures, the pivoting portion of the shackle is axially moveable relative to the housing under the control of the driving wheels of the retaining device, such that the locking end of the shackle is moveable away from the second top hole of the housing to unlock the padlock. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a perspective view of a padlock according to a preferred embodiment of the present invention; 
         FIG. 2  is an exploded view of the padlock according to the preferred embodiment of the present invention; 
         FIG. 3  is a front view of the padlock according to the preferred embodiment of the present invention; 
         FIG. 4  is a rear view of the padlock according to the preferred embodiment of the present invention, in which the base is removed; 
         FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4 ; 
         FIG. 6  is a partial exploded view of the padlock according to the preferred embodiment of the present invention, showing the padlock is unlocked; 
         FIG. 7  is a partial exploded view of the padlock according to the preferred embodiment of the present invention, showing the padlock is locked; 
         FIG. 8  is a rear view of the padlock according to the preferred embodiment of the present invention, showing the tab is located at the second position; 
         FIG. 9  is a partial exploded view of the padlock according to the preferred embodiment of the present invention, showing the protrusion of the tab is engaged with the recess of the latch, and 
         FIG. 10  is a perspective view of the padlock according to the preferred embodiment of the present invention, showing a band is connected with the housing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 to 3 , a padlock  10  in accordance with a preferred embodiment of the present invention comprises a housing  20 , a shackle  30 , a retaining device  40 , a first pointer  50 , a second pointer  52 , a third pointer  54 , and an adjusting member  60 . 
     The housing  20  includes a top lid  22  and a base  24  coupled to the top lid  22  so as to define an accommodation chamber  202 , a first top hole  204  in communication with the accommodation chamber  202 , and a second top hole  206  in communication with the accommodation chamber  202 . The housing  20  has a dial  26  mounted on a top side of the top lid  22  and provided with a plurality of figures  262 , which are embodied as Arabic numerals 1 to 12 in this embodiment, and a transparent cover  28  covered on the dial  26 . 
     The housing  30  has a pivoting portion  32  passing through the first top hole  204  of the housing  20  into the accommodation chamber  202  of the housing  20  and axially movable and pivotable relative to the housing  20 , a block portion  34  provided at a bottom end of the pivoting portion  32 , and a hook portion  36  integrally connected with the pivoting portion  32  and having a locking end  362  insertable into the second top hole  206  of the housing  20 . 
     The retaining device  40  includes a latch  41 , a block member  42 , three driving wheels  43   a - 43   c , a first transmission wheel  44 , a second transmission wheel  45 , a third transmission wheel  46 , three retaining wheels  47 , and an elastic member  48 . 
     The latch  41  is mounted in the accommodation chamber  202  of the housing  20  and movable relative to the housing  20 . The latch  41  is provided at a bottom thereof with three insertion portions  412 , each of which is formed as a trapezoid having two first beveled surfaces  414 , as shown in  FIG. 2 . The latch  41  further includes an inclined groove  416  at a middle thereof with a top end defining with the pivoting portion  32  of the shackle  30  a distance that is longer than a distance defined between a bottom end of the inclined groove  416  and the pivoting portion  32  of the shackle  30 , as shown in  FIG. 4 , and a recess  418  at a rear side thereof. 
     The block member  42  has a block end  424  and a connection end  422  inserted into the inclined groove  416  of the latch  41  and slidable between the two ends of the inclined groove  416  of the latch  41 , as shown in  FIGS. 6 and 7 , such that the block end  424  can approach or leave the pivoting portion  32  of the shackle  30 . 
     The driving wheels  43   a - 43   c  are rotatably mounted in the accommodation chamber  202  of the housing  20  and partially extend out of the housing  20  for user&#39;s operation. Each of the driving wheels  43   a - 43   c  has twelve indentations  432   a - 432   c  on the periphery thereof. 
     The first transmission wheel  44  has a first gear  441  engaged with the indentation  432   a  of the driving wheel  43   a  such that the first transmission wheel  44  can be driven by the driving wheel  43   a  to rotate and a first shaft  443  extending from a center of the first gear  441 , as shown in  FIG. 2 , and penetrating through the top lid  22  of the housing  20  and projecting out of the dial  26  of the housing  20 , as shown in  FIG. 5 . 
     The second transmission wheel  45  has a second gear  452  engaged with the indentations  432   b  of the driving wheel  43   b  such that the second transmission wheel  45  can be driven by the driving wheel  43   b  to rotate, and a second shaft  454  coaxially sleeved onto the first shaft  443  of the first transmission wheel  44  and penetrating through the top lid  22  of the housing  20  and projecting out of the dial  26  of the housing  20 . The second shaft  454  is shorter in length than the first shaft  443  such that a distal end of the first shaft  443  is protruded out of a distal end of the second shaft  454 , as shown in  FIG. 5 . 
     The third transmission wheel  46  has a third gear  462  engaged with the indentation  432   c  of the driving wheel  43   c  such that the third transmission wheel  46  can be driven by the driving wheel  43   c  to rotate, and a third shaft  464  coaxially sleeved onto the second shaft  454  of the second transmission wheel  45  and penetrating through the top lid  22  of the housing  20  and projecting out of the dial  26  of the housing  20 . The third shaft  464  is shorter in length than the second shaft  454  such that a distal end of the second shaft  454  is protruded out of a distal end of the third shaft  464 , as shown in  FIG. 5 . 
     The retaining wheels  47  are respectively sleeved onto the first shaft  443  of the first transmission wheel  44 , the second shaft  454  of the second transmission wheel  45 , and the third shaft  464  of the third transmission wheel  46  so as to be respectively rotated with the first transmission wheel  45 , the second transmission wheel  46 , and the third transmission wheel  47 . Each retaining wheel  47  has a notch  472  with two second beveled surfaces  474  matched up with the first beveled surfaces  414  of the latch  41 . 
     The elastic member  48  is mounted in the accommodation chamber  202  of the housing  20  and has two ends respectively stopped against a periphery of the accommodation chamber  202  of the housing  20  and the latch  41  for providing an elastic force to push the latch  41  toward the retaining wheels  47 . 
     The first pointer  50 , the second pointer  52 , and the third pointer  54  are respectively connected to the first shaft  443  of the first transmission wheel  44 , the second shaft  454  of the second transmission wheel  45 , and the third shaft  464  of the third transmission wheel  46  and located above the dial  26  of the housing  20 , as shown in  FIG. 5 , such that the first pointer  50 , the second pointer  52 , and the third pointer  54  can be respectively driven by the first transmission wheel  44 , the second transmission wheel  45 , and the third transmission wheel  46  to point to one of the figures  262 . When all of the first pointer  50 , the second pointer  52 , and the third pointer  54  point to predetermined correct figures  262 , the insertion portions  412  of the latch  41  are inserted into the notches  472  of the retaining wheels  47 , as shown in  FIG. 6 , such that the connection end  422  of the block member  42  moves to the top end of the inclined groove  416  of the latch  41  and the block end  424  of the block member  30  leaves the block portion  34  of the shackle  30 , resulting in that the pivoting portion  32  of the shackle  30  can be axially moved and therefore the locking end  362  of the shackle  30  can be moved away from the second top hole  206  of the housing  20  to unlock the padlock  10 . On the contrary, when one of the first pointer  50 , the second pointer  52 , and the third pointer  54  points to an incorrect  figure 262 , the insertion portions  412  of the latch  41  and the notches  472  of the retaining wheels  47  are staggered, as shown in  FIG. 7 , such that the connection end  422  of the block member  42  moves to the bottom end of the inclined groove  416  of the latch  41  and the block end  424  of the block member  42  blocks the block portion  34  of the shackle  30 , resulting in that the pivoting portion  32  of the shackle  30  cannot be axially moved and therefore the locking end  362  of the shackle  30  cannot be moved away from the second top hole  206  of the housing  20 . 
     The adjusting member  60  is mounted in the accommodation chamber  202  of the housing  20 , including a tab  62  and a linking member  64 , as shown in  FIG. 2 . The tab  62  has a protrusion  622  coupled to the linking member  64  and a bottom side exposed out of the base  24  of the housing  20  for enabling the tab  62  to be driven by an external force to make the adjusting member  60  move between a first position where the protrusion  622  of the tab  62  is disengaged from the recess  418  of the latch  41 , as shown in  FIG. 6 , and therefore the latch  41  can be moved upwards, and a second position where the protrusion  622  of the tab  62  is engaged with the recess  418  of the latch  41 , as shown in  FIG. 9 , and therefore the latch  41  cannot be moved upwards 
     When a user would like to unlock the padlock  10  and the code to unlock the padlock  10  is set to two o&#39;clock and fifty minutes as an example, he/she can rotate the driving wheel  43   c  to move the third pointer  54  to point to Arabic numeral 2 through the third transmission wheel  46 , and then rotates the driving wheel  43   b  to move the second pointer  52  to point to Arabic numeral 10 through the second transmission wheel  45 , and then rotates the driving wheel  43   a  to move the first pointer  50  to point to Arabic numeral 12, as shown in  FIG. 3 . As a result, the insertion portions  412  of the latch  41  are inserted into the notches  472  of the retaining wheels  47 , as shown in  FIG. 6 , and the connection end  422  of the block member  42  moves to the top end of the inclined groove  416  of the latch  41  such that the block end  424  of the block member  30  leaves the block portion  34  of the shackle  30 . Therefore, the user can pull upwards the hook portion  36  of the shackle  30  to enable the locking end  362  of the shackle  30  to leave the second top hole  206  of the housing  20  and enable the pivoting portion  32  of the shackle  30  to pivot relative the housing  20 , thereby unlocking the padlock  10 . 
     When the user would like to lock the padlock  10 , he/she can press the hook portion  36  of the shackle  30  to make the locking end  362  of the shackle  30  insert into the second top hole  206  of housing  20 , and then rotates the driving wheels  43   a - 43   c  to drive the retaining wheels  47  to rotate. At this time, the second beveled surfaces  474  of the notches  472  of the retaining wheels  47  will push upwards the first beveled surfaces  414  of the insertion portions  412  of the latch  41  to force the insertion portions  412  of the latch  41  to leave the notches  472  of the retaining wheels  47 , as shown in  FIG. 7 . Accordingly, the block member  42  will approach the block portion  34  of the shackle  30  such that the connection end  422  of the block member  42  moves to the bottom end of the inclined groove  416  of the latch  41  and the block end  424  of the block member  42  blocks the block portion  34  of the shackle  30 , resulting in that the pivoting portion  32  of the shackle  30  cannot be axially movable. 
     The code to unlock the padlock  10  can be changed according to the user&#39;s requirement. In the code changing processes, the user can rotate the driving wheels  43   a - 43   c  to move the first pointer  50 , the second pointer  52 , and the third pointer  54  to point to the previously set correct figures  262  first for enabling the insertion portions  412  of the latch  41  to be inserted into the notches  472  of the retaining wheels  47 , and then forces the tab  62  to move to the second position where the protrusion  622  of the tab  62  is engaged with the recess  418  of the latch  41 , as shown in  FIG. 8  and  FIG. 9 , and then rotates the driving wheels  43   a - 43   c  to drive the first transmission wheel  44 , the second transmission wheel  45 , and the third transmission wheel  46  to rotate. At this time, the retaining wheels  47  cannot force the latch  41  to move upwards due to the engagement of the protrusion  622  and the recess  418  and cannot be rotated with the first transmission wheel  44 , the second transmission wheel  45 , and the third transmission wheel  46  due to the engagement of the insertion portions  412  and the notches  472 . In this situation, when the driving wheels  43   a - 43   c  are rotated, the first transmission wheel  44 , the second transmission wheel  45 , and the third transmission wheel  46  will run idly relative to the retaining wheels  47 . Therefore, as long as the user rotates the driving wheels  43   a - 43   c  to move the first pointer  50 , the second pointer  52 , and the third pointer  54  to set a new code and then forces the tab  62  to move to the first position, the code changing process of the padlock  10  is completed. 
     As shown in  FIG. 10 , the padlock  10  can include a band  70  with one end connected with a bottom of the housing  20  and the other end curvedly extending such that the padlock  10  can be worn on the user&#39;s wrist for convenience of use and decoration. 
     By means of the aforesaid design, the padlock is designed as a watch, i.e. the first pointer, the second pointer, and the third pointer are respectively regarded as a second hand, a minute hand, and an hour hand. Thus, the user has to rotate all of the pointers to point to the correct time for unlocking the padlock such that the padlock of the invention has a safety burglarproof effect and uncomplicated structure. Besides, the padlock of the invention can be made like an alarm clock or a bomb as long as the padlock can be unlocked by rotating the pointers. In addition, the padlock of the invention can be made with various kinds of design. For example, the number of the driving wheels, the transmission wheels, and the retaining wheels is not limited to the above-mentioned embodiment as long as the driving wheels, the transmission wheels, and the retaining wheels are equivalent in amount. Further, the figures are not limited to Arabic numerals but can be presented in English letters or other symbols. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Summary:
A padlock includes a housing, a shackle having a pivoting portion pivotally passing through a first top hole of the housing into an accommodation chamber of the housing and a locking end passing through a second top hole of the housing, a retaining device disposed in the accommodation chamber and having at least two driving wheels for controlling an axial movement of the pivoting portion of the shackle, and at least two pointers located above a dial of the housing and respectively driven by the driving wheels to point to one of figures of the dial. When both of the pointers point to correct figures, the pivoting portion of the shackle is axially moveable relative to the housing under the control of the driving wheels, such that locking end of the shackle is moveable away from the second top hole of the housing to unlock the padlock.