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  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to locks and more particularly, to a lock assembly, which is the combination of a combination lock and a pin tumbler lock.  
         [0003]     2. Description of the Related Art  
         [0004]     Conventional locks mainly include two types, namely, the combination lock operatable by a plurality of numbered wheels and the pin tumbler lock operatable by a key. If a suitcase uses a combination lock, the user must rotate the numbered wheels of the combination lock to show the correct combination when wishing to open the suitcase. If a suitcase uses a pin tumbler lock, the user must insert the correct key into the keyway of the pin tumbler lock and then rotate the plug of the pin tumbler lock with the key to the unlocking position when wishing to open the suitcase.  
         [0005]     If a suitcase uses a combination lock and the user forgets the correct combination of the combination lock, the user must deliver the suitcase to the distributor or a locksmith to open the combination lock. If a suitcase uses a pin tumbler lock and the user does not have the key in hand, the user still cannot open the suitcase.  
         [0006]     Further, in order to prevent a terrorist attach, customs clerks may have to check suitcases and luggage. When checking a suitcase that uses a combination lock, the customs clerk must destroy the suitcase so that the content of the suitcase can be seen. In this case, a dispute may arise between the customs clerk and the passenger.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a lock assembly, which is the combination of a combination lock and a pin tumbler lock and can be conveniently opened by selectively using the numbered wheels of the combination lock or the key of the pin tumbler lock.  
         [0008]     To achieve this object of the present invention, the lock assembly comprises a casing, a combination lock and a pin tumbler lock mounted respectively in the casing. The combination lock has a plurality of numbered wheels and a lifting plate movable relative to the numbered wheels. The pin tumbler lock has a plug rotatable between a locked position and an unlocked position. The plug has an actuating block which stops at the lifting plate when the plug is in the locked position and moves the lifting plate away from the numbered wheels when the plug is moved from the locked position to the unlocked position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an exploded view of a lock assembly according to a preferred embodiment of the present invention.  
         [0010]      FIG. 2  is a schematic top view of the lock assembly according to the preferred embodiment of the present invention.  
         [0011]      FIG. 3  is a sectional view of the preferred embodiment of the present invention, showing positions of the lifting plate and the sliding plate after unlocking of the combination lock.  
         [0012]      FIG. 4  is a sectional view of the preferred embodiment of the present invention, showing positions of the lifting plate and the sliding plate after locking of the combination lock.  
         [0013]      FIG. 5  is similar to  FIG. 2  but showing the status of the lock assembly after unlocking of the pin tumbler lock.  
         [0014]      FIG. 6  is similar to  FIG. 4  but showing the status of the lock assembly after unlocking of the pin tumbler lock. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     As shown in  FIGS. 1 and 2 , a lock assembly  10  in accordance with the preferred embodiment of the present invention comprises a casing  20 , a combination lock  30 , a sliding plate  40 , and a pin tumbler lock  50 .  
         [0016]     The casing  20 , which can be firmly fastened to a half shell (not shown) of a suitcase or a luggage, comprises a flat rectangular bottom wall  202 , two first sidewalls  204  respectively perpendicularly extending from the two opposite long sides of the flat rectangular bottom wall  202 , two second sidewalls  206  respectively perpendicularly extending from the two opposite short sides of the flat rectangular bottom wall  202  and respectively fixedly connected between the first sidewalls  204 . The flat rectangular bottom wall  202 , the first sidewalls  204  and the second sidewalls  206  define a rectangular receiving open chamber  22 . Two locating plates  24  are fixedly mounted inside the rectangular receiving open chamber  22  in vertical posture and arranged in parallel. Each of the locating plates  24  has a through hole  242  and a locating notch  244 . The casing  20  further has two openings  208  formed in one first sidewall  204  for insertion of two hooks of a locking bar  26  that can be firmly fastened to another half shell (not shown) of a suitcase or a luggage.  
         [0017]     The combination lock  30  comprises a shaft  31 , three numbered wheels  32  mounted on the shaft  31 , three actuating wheels  33  respectively mounted in the numbered wheels  32  and supported on the shaft  31 , a lever  34  supported on the shaft  31  and coupled to one of the actuating wheels  33 , and a lifting plate  35  for supporting the numbered wheels  32  and the actuating wheels  33 . The lifting plate  35  is engagable with the hooks of the locking bar  26  when the locking bar  26  is inserted into the casing  20  through the openings  208 . The combination lock  30  is installed in the receiving open chamber  22  of the casing  20  by means of inserting two distal ends of the lifting plate  35  into the through holes  242  of the locating plates  24 . Further, the lifting plate  35  has a butt  352  at the bottom side and a stop rod  354  at one end. Rotating the numbered wheels  32  can cause a vertical movement of the lifting plate  35  relative to the numbered wheels  32 . When the numbered wheels  32  are aligned to show the correct combination, the combination lock  30  is opened, i.e. the locking bar  26  can be moved away from the lifting plate  35 .  
         [0018]     The sliding plate  40  is moveably mounted in the receiving open chamber  22  of the casing  20  and coupled to the locating notches  244  of the locating plates  24 . The sliding plate  40  has an oval insertion slot  42  cut through the top and bottom walls thereof at one end, and a rectangular through hole  44  cut through the top and bottom walls on the middle thereof.  
         [0019]     The pin tumbler lock  50  comprises a plug holder  52  fixedly mounted in the receiving open chamber  22  of the casing  20 , and a plug  54  inserted through the plug holder  52  and secured thereto by a C-shaped retainer  56 . The plug  54  can be rotated with the key (not shown) relative to the plug holder  52  between a locking position and an unlocking position. The plug  54  has a keyway  542  in the top side for the insertion of the key, a bottom pin  544  inserted through the insertion slot  42  of the sliding plate  40 , and a bottom actuating block  546 , which has a beveled actuating face  548  stopped against the stop rod  354  of the lifting plate  35  of the combination lock  30 . When the user inserting the key into the keyway  542  to rotate the plug  54  to the unlocking position, the sliding plate  40  will be moved toward the combination lock  30  by the bottom pin  544 , and at the same time the stop rod  354  of the lifting plate  35  of the combination lock  30  will be forced by the actuating block  546  to lower the lifting plate  35  relative to the numbered wheels  32 , thereby forcing the butt  352  into the rectangular through hole  44  of the sliding plate  40 . When the pin tumbler lock  50  is in the locking position, the actuating block  546  is stopped against the stop rod  354  of the lifting plate  35  of the combination lock  30 , and the butt  352  is disengaged from the rectangular through hole  44  of the sliding plate  40 .  
         [0020]     Referring to  FIG. 3 , when the lock assembly  10  is used in a suitcase (not shown) and the user wishes to open the suitcase by means of the combination lock  30 , the user must rotate the numbered wheels  32  to show the correct combination so as to further unlock the combination lock  30 . When the combination lock  30  is unlocked, the butt  352  is kept away from the rectangular through hole  44  of the sliding plate  40 , the lifting plate  40  and the locking bar  26  are in a staggered manner, and the lifting plate  35  is suspending above the locking bar  26 .  
         [0021]     Referring to  FIG. 4 , when the user rotating the numbered wheels  32  to lock the combination lock  30 , the lifting plate  35  will be lowered relative to the numbered wheels  32  to the same elevation of the locking bar  26  so that the locking bar  26  can not be moved out of the casing  20  due to the interference of the lifting plate  35 .  
         [0022]     Referring to  FIGS. 5 and 6 , if the user cannot remember the correct combination of the combination lock  30  or if the customs clerk wishes to check the content of the suitcase but doesn&#39;t know the correct combination of the combination lock  30 , the key can be inserted into the keyway  542  of the pin tumbler lock  50  and rotated to move the sliding plate  40  toward the combination lock  30  and to simultaneously force the actuating block  546  against the stop rod  354  of the lifting plate  35  of the combination lock  30 , thereby lowering the lifting plate  35  to force the butt  352  of the lifting plate  35  into the rectangular through hole  44  of the sliding plate  40 . At this time, the lifting plate  35  and the locking bar  26  are again in a staggered manner, i.e. the lifting plate  35  is kept below the elevation of the locking bar  26 ; therefore, the hooks of the locking bar  26  can be freely moved away from the openings  208  of the casing  20 . This means that the suitcase can be opened.  
         [0023]     By means of the linking design of the combination lock  30  and the pin tumbler lock  50 , the user can selectively use the combination lock  30  or the pin tumbler lock  50  to open the suitcase. When the customs clerk wishes to check the content of the suitcase, the pin tumbler lock  50  can be operated to open the suitcase even if the combination lock is in the locked manner.  
         [0024]     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.

Summary:
A lock assembly includes a casing accommodating therein a combination lock and a pin tumbler lock. The combination lock has a set of numbered wheels and a lifting plate vertically movable relative to the numbered wheels. The pin tumbler lock has a plug rotatable between a locked position and an unlocked position. The plug has an actuating block which stops at the lifting plate when the plug is in the locked position and moves the lifting plate away from the numbered wheels when the plug is moved from the locked position to the unlocked position.