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 
   1. Field of the Invention 
   The present invention relates generally to a lock, and more particularly, to a dual padlock, which may open by key or by code. 
   2. Description of the Related Art 
   Typically, conventional padlocks are classified into key lock, which may be opened by specific key, and combination lock, which may be opened by inputting specific code. 
   For the combination lock, if user forgot the code, he/she has to ask locksmith for help, or break the lock to open it. For the key lock, if user lost the key, he/she still has the same trouble to open it. 
   In addition, the Customs in airports usually ask passengers to have their luggage unlocked for a routine check. If passengers use the combination lock and forgot to open it, the Customs members will have trouble to open the luggage, sometime, they just break such luggage, and that cause dispute between passengers and Customs. 
   SUMMARY OF THE INVENTION 
   The primary objective of the present invention is to provide a dual padlock, which may be opened by key or by inputting code. 
   The secondary objective of the present invention is to provide a dual padlock, with which the Customs members have no trouble to open it for a routine check. 
   The third objective of the present invention is to provide a dual padlock, with which user is easy to identify whether his/her luggage had been opened by the key of Customs members. 
   To achieve the foregoing objectives of the present invention, a dual padlock includes a housing, a shackle, a locking device, a locking spring, a transmission device, a code lock assembly, and a button member. The housing has a chamber inside, two top bores, a through bore, a button bore, and a plurality of dial bores. The shackle has a pivot end and a movable end inserted into the top bores of the housing respectively. The pivot end is formed with a head portion in the chamber, and the movable end has a slot. The locking device, which is received in the chamber of the housing, has a locking portion to be moved between a first position, in which the locking portion is engaged with the slot of the shackle, and a second position, in which the locking portion is disengaged with the slot of the shackle. The locking spring is received in the chamber of the housing and urges the locking device. The key lock assembly includes a key cylinder, which is received in the chamber of the housing and has an end received in the through bore, has a keyhole and a spiral slot. The transmission device has an end received in the spiral slot of the key cylinder of the key lock assembly and opposite end touching the locking device to be moved by the key cylinder. The code lock assembly is received in the chamber of the housing and has a shaft, a plurality of numeral wheels, which are fitted to the shaft and received in the dial bores respectively, and a return spring urging the shaft. The button member is pivoted on an interior side of the housing and has a first arm, which is received in the button bore of the housing and touches the shaft of the code lock assembly, and a second arm touching the locking device. Therefore, the dual padlock of the present invention may be opened by key and by input the right code. 
   In addition, the combination of the present invention may be provided with a first spring and a second spring urging the movable end the pivot end of the shackle to inject the shackle when the padlock is opened. It may be provided with a block urged by the first spring to prevent the locking device from affecting the action of the first spring. 
   The locking portion of the locking device may be provided with a sloping face to help the engagement of the locking device and the movable end of the shackle. The locking portion of the locking device may be provided with an arched gap to be engaged with the slot of the shackle firmly. 
   The dual padlock of the present invention further includes an indicator. The indicator is received in the chamber of the housing and is pivoted on the housing to be moved by the transmission device between a third position, in which the indicator is on a path of the transmission device, and a fourth position, in which the indicator is on a path of the button member. The housing is provided with a window that the indicator is visible through the window when the indicator is moved to the fourth position to identify whether the dual padlock of the present invention had been opened by key. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a first preferred embodiment of the present invention; 
       FIG. 2  is an exploded view of the first preferred embodiment of the present invention; 
       FIG. 3  is a sectional view of the first preferred embodiment of the present invention, showing the inside structure of the padlock; 
       FIG. 4  is similar to in  FIG. 3 , showing the pad lock been opened by code; 
       FIG. 5  is similar to in  FIG. 3 , showing the pad lock been opened by key; and 
       FIG. 6  is a sectional view of a second preferred embodiment of the present invention, showing the inside structure of the padlock. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 to 5 , a dual padlock  10  constructed according to the first preferred embodiment of the present invention includes a housing  20 , a shackle  30 , a first spring  36 , a second spring  38 , a locking device  40 , a locking spring  45 , a key lock assembly  50 , a transmission device  56 , a code lock assembly  60 , a button member  70 , an indicator  76  and a third spring  78 . 
   The housing  20  is constructed by a front case  201  and a rear case  103  to form a chamber  21  therein. The housing  20  has two top bores  22 , a through bore  23 , a button bore  24 , three dial bores  25  and a window  26 . The top bores  22 , the through bore  23 , the button bore  24 , the dial bores  25  and the window  26  communicate the chamber  21  with outside. 
   The shackle  30  is a U-shaped bar having a pivot end  32  and a movable end  34 . The pivot end  32  is inserted into one of the top bores  22  of the housing  20  and has a head portion  321  received in the chamber  21  of the housing  20 . The movable end  34  is inserted into another top bore  22  of the housing  20  and has an annular slot  341 . 
   The first spring  36  is received in the chamber  21  of the housing  20 . A block  361  is urged by the first spring  36  to keep touching the movable end  34  of the shackle  32 . 
   The second spring  38  is received in the chamber  21  of the housing  20  to urge the pivot end  32  of the shackle  32 . 
   The locking device  40 , which is received in the chamber  21  of the housing  20 , has a locking portion  42 . The locking portion  42  includes an arched gap  421 , which is complementary to a bottom end of the annular slot  341  of the shackle  30 , and a sloping face  423 . The locking device  40  is moved between a first position, in which the locking portion  42  is engaged with the annular slot  341  of the shackle  30  ( FIG. 3 ), and a second position, in which the locking portion  42  is disengaged with the annular slot  341  of the shackle  30  ( FIG. 4  and  FIG. 5 ). 
   The locking spring  45  is received in the chamber  21  of the housing  20  to urge the locking device  40  toward the first position. 
   The key lock assembly  50  includes a lock base  52  received in the chamber  21  of the housing  20  and a lock cylinder  54  received in the through bore  23 . The lock cylinder  54  has a keyhole  541  at an outer end thereof and a spiral slot  543  adjacent to an inner end thereof. A key (not shown) may be inserted into the keyhole  541  to turn the lock cylinder  54 . The key lock assembly  50  is a conventional device, so we do not describe the detail here. 
   The transmission device  56  has an end inserted into the slot  543  of the lock cylinder  54  and the other end touching the locking device  40  so that the transmission device  56  is moved by the lock cylinder  54  to move the locking device  40  to the second position from the first position. 
   The code lock assembly  60 , which is received in the chamber  21  of the housing  20 , has a shaft  62 , three numeral wheels  64 , three locking wheels  66 , a positioning spring piece  68  and a return spring  69 . The shaft  62  is formed with an extending wall  621  at an end thereof. The numeral wheels  64  are fitted to the shaft  62  and received in the dial bores  25  of the housing  20  respectively to be turned by user. The locking wheels  66  fitted to the shaft  62  and touch the numeral wheels  64  respectively. The return spring  69  is fitted to the shaft  62  and urges the extending wall  621  to urge the shaft  62  toward the button member  70 . When the numeral wheels  64  are turned to setting positions, the shaft  62  may be move freely, otherwise, the shaft  62  will be restricted by the locking wheels  66 . The code lock assembly  60  is a conventional device, so we do not describe the detail here. 
   The button member  70  has a hole  71  at a center thereof to be fitted to a shaft  205  on an interior side of the rear case  203 . The button member  70  further has a first arm  72 , which is inside the button bore  24  and touches the extending wall  621  of the shaft  62  of the code lock assembly  60 , and a second arm  74 , which touches the locking device  40  to move the locking device  40  to the second position from the first position. The second arm  74  is formed with a curved face  741 . 
   The indicator  76  is pivoted on the rear case  203  of the housing  20  and is received in chamber  21  to be swung between a third position, in which the indicator  76  is on a path of the transmission  56  ( FIG. 3  and  FIG. 4 ), and a fourth position, in which the indicator  76  is on a path of the button member  70 . The indicator  76  is visible through the window  26  when it is moved to the fourth position, and is invisible when it is moved to the third position. The indicator  76  is formed with a sliding shaft  761 . 
   The third spring  78  is received in the chamber  21  of the housing  20  to urge the indicator  76  and an inner side of the housing  20  to move the indicator  76  approaching the window  26  of the chamber  21  as possible. 
   When the padlock  10  of the present invention is locked, as shown in  FIG. 3 , the locking device  40  is at the first position to engage the locking portion  42  thereof with the annular slot  341  of the shackle  30  that the shackle  30  is secured. The first arm  72  of the button member  70  is restricted by the shaft  62  that the button member  70  can not swing in such condition. When user turns the numeral wheels  64  to the right code, the locking wheels  66  release the shaft  62 , and when the user presses the first arm  72  of the button member  70 , the second arm  74  of the button member  70  will move to the second position, as shown in  FIG. 4 , that the first spring  36  and the second spring  38  will eject the shackle  30  to unlock the padlock  10  of the present invention. 
   To relock the padlock  10  of the present invention, user only has to press the shackle  30  to compress the first spring  36  and the second spring  38  that the locking device  40  will moved by the locking spring  45  to the first position. As a result, the padlock  10  of the present invention is locked. 
   When user inserts the key (not shown) into the keyhole  541  of the key lock assembly  50  and turns, the lock cylinder  54  is turned to move the locking device  40 , through the transmission device  56 , to second position from the first position, as shown in  FIG. 5 , that the shackle  30  will be ejected to unlock the padlock  10  of the present invention. The padlock  10  of the present invention provides user choice to open it by key or by code that has much convenient to users. In addition, if user forgot to open the luggage with the padlock  10  of the present invention, the Customs member may open it by key for check procedure. 
   The indicator  76  is moved to the fourth position ( FIG. 5 ) from the third position ( FIG. 4 ) when the padlock  10  of the present invention is opened by key, and the indicator  76  will be left at the fourth position still when the padlock is relocked that user may identify whether his/her luggage had been opened by Customs member. When user presses the button member again, the second arm  74  of the button member  70  is turned clockwise to move the sliding shaft  761  of the indicator  76  along the curved face of the second arm  74  to return the indicator  76  to the third position. 
   There are many equivalent structures according the scope of the present invention. As shown in  FIG. 6 , a dual padlock  80  of the second preferred embodiment of the present invention, which is similar to the first preferred embodiment, includes a housing  81 , a first spring  83 , a locking device  84 , a key lock assembly  85 , a transmission device  86 , a code lock assembly  87 , a button member  88 , an indicator  89  and a third spring  90 . A different part of the padlock  80  of the second preferred embodiment includes that a shackle  82  having a flexible cable  821  and two connecting device  823 ,  825 , which act as the pivot end and movable end respectively. Another different part of the padlock  80  of the second preferred embodiment is that it has no second spring. 
   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.

Summary:
A dual padlock of the present invention includes a housing, a shackle, a locking device, a locking spring, a transmission device, a key lock assembly, a code lock assembly, and a button member. The shackle is openably provided on the housing. The locking device is received in the chamber of the housing and engaged with the shackle. The key lock assembly includes a key cylinder connected to the transmission device and the locking device. The button member is connected to a shaft of the code lock assembly and the lock device. Therefore, user may insert a key into the key lock assembly and turns to unlock the padlock. User also may input the right code to the code lock assembly that will unlock the pad lock too.