Patent Publication Number: US-2022234385-A1

Title: Trolley bag with separated middle frame and hinge and having shock-absorbing structure

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
     This application is a continuation of PCT patent Application No. PCT/CN2020/132563, filed on Nov. 30, 2020, entitled “TROLLEY BAG WITH SEPARATED MIDDLE FRAME AND HINGE AND HAVING SHOCK-ABSORBING STRUCTURE,” which claims foreign priority of Chinese Patent Application No. 201911232258.3, filed Dec. 5, 2019 in the China National Intellectual Property Administration (CNIPA), the entire contents of which are hereby incorporated by reference in their entireties. 
    
    
     FIELD OF THE DISCLOSURE 
     The invention relates to a trolley bag, especially to a trolley bag with separated middle frame and hinge and having shock-absorbing structure 
     BACKGROUND OF THE DISCLOSURE 
     A trolley bag refers to a luggage with a trolley handle and wheels. Because of its convenience, it is an essential item for people to travel. With the rapid development of the tourism industry, the growth of the travel market has brought consumers&#39; increasing demand for trolley bags, and also new opportunities and challenges for trolley bag manufactures. 
     At present, some of the trolley bags on the market do not have the shock-absorbing function. Although the others may absorb shock by having springs, the fabrication thereof can be complicated and cost a lot. In addition, the conventional zipper luggage is prone to deformation, resulting in inflexible movement of the wheel seat. The conventional middle-frame bags are too heavy to move. Furthermore, conventional locks on the trolley bags on the market require a lot of force to press after the luggage is full. 
     SUMMARY OF THE DISCLOSURE 
     Accordingly, an object of the present invention is to provide a trolley bag with separated middle frame and hinge and having shock-absorbing structure to solve the deficiency of the prior art. 
     In order to solve the aforementioned technical problem, the present invention provides the following technical solutions: a trolley bag with separated middle frame structure and hinge and having shock-absorbing structure includes a trolley handle, a rear case, a middle frame, and a front case. The middle frame structure includes a hinge structure and a pair of middle frames. One of the pair of middle frames is connected to the rear case, and the other one is connected to the front case. The present invention is characterized in that the hinge structure includes a pair of hinges and a core pin, one of the pair of hinges is connected to one of the middle frames, the other is connected to the other one of the middle frames. The pair of hinges are movably connected through the core pin. The pair of middle frames is locked together by an interlocking assembly. Shock-absorbing wheels are arranged at four corners of a bottom of the trolley bag. 
     Furthermore, the hinge has a connecting portion. A side wall of the connecting portion is provided with at least one rib portion at intervals along a length direction of the connecting portion. The middle frame is provided with a groove portion, and a bottom surface of the groove portion is provided with a connecting groove. A baffle portion matched with the rib portion is arranged on a side wall of the connecting groove. A notch adapted for the rib portion is formed on a rear side of the baffle portion. When the hinges are installed on the middle frames, the bottom surface of the baffle portion abuts against a top surface of the rib portion. The top of the connecting portion is spaced and connected to a plurality of bushings along the length direction of the connecting portion. Each of the bushings is provided with an axis hole matching with the core pin. The bushings of the pair of hinges are hinged through the core pin. 
     Furthermore, a front end of the connecting portion is connected to a first engaging portion. A front side of the groove portion is provided with a second engaging portion. A slot is opened on the second engaging portion. The first engagement portion is inserted into the slot to form a snap connection with the second engagement portion. 
     Furthermore, a top of the slot is provided with a snap hole, and a top of the first engagement portion is provided with a snap protrusion adapted for the snap hole. 
     Furthermore, a top surface of the rib portion is a first inclined surface which is formed obliquely. A bottom surface of the baffle portion is a second inclined surface which is formed obliquely. An angle between the second inclined surface and the side wall of the connecting groove is an acute angle. When the hinges are installed on the middle frames, the second inclined surface abuts against the first inclined surface. 
     Furthermore, the interlocking assembly includes a main lock. The two middle frames include a first middle frame and a second middle frame. The main lock is arranged on a side of the first middle frame opposite to the side where the hinge structure is located. The second middle frame is provided with a plurality of lock hooks adapted for the main lock. 
     Furthermore, the main lock includes a main lock case, a control mechanism and a pair of main lock cylinder assemblies. The control mechanism and the pair of main lock cylinder assemblies are both arranged on the main lock case, and the pair of main lock cylinder assemblies are respectively located on both sides of the control mechanism. The control mechanism is capable of controlling on and off of the pair of main lock cylinder assemblies. 
     Furthermore, the control mechanism includes a drive assembly and a customs lock. The customs lock and the drive assembly are both arranged in the main lock case. 
     Furthermore, the drive assembly includes a pusher, a reduction gear, a first rack and a second rack. The pusher is slidably arranged in the main lock case, and a push torque of the pusher protrudes over a through hole on a lock cover of the main lock case. A top of the pusher is provided with a top plate portion. A lower portion of the top plate portion is provided with a rack portion. The first rack is slidably arranged in the main lock case. The first rack is connected to one of the main lock cylinder assemblies. The second rack is slidably arranged in the main lock case. The second rack is connected to another one of the main lock cylinder assemblies. The top plate portion controls the first rack and the second rack by the reduction gear. 
     Furthermore, the main lock cylinder assembly includes a first button, a first gear and a first spring. A plurality of protruding teeth is arranged on one side of the lock hook. The first gear is rotatably arranged in the main lock case. The first gear is capable of being engaged with the plurality of protruding teeth on the lock hook. The first button is rotatably arranged in the main lock case. One end of the first button adjacent to the first gear has one side on which a tooth slot portion is arranged. The other end of the first button is movably connected to the first rack or the second rack. The first spring is connected between the other end of the first button and the first rack or the second rack. The first spring is capable of allowing the tooth slot portion of the first button to connect to the tooth of the first gear. 
     Furthermore, the main lock also includes a ball plunger and a ball plunger spring. The ball plunger is movably arranged in the main lock case. The ball plunger spring is arranged between the ball plunger and the main lock case. The ball plunger spring makes the ball plunger abut against the pusher. The pusher is provided with a first indication hole and a second indication hole which are adapted for the ball plunger. 
     Furthermore, the interlocking assembly also includes a plurality of side locks that are interlocked with the main lock. At least one side lock is arranged on an upper side of the first middle frame, and at least one side lock is arranged on a lower side the first middle frame. The second middle frame is provided with a plurality of lock hooks adapted for the side locks. The control mechanism is capable of controlling the on and off of the pair of main lock cylinder assemblies while controlling the on and off of the plurality of side locks. 
     Furthermore, each of the side locks includes a side lock case and a side lock cylinder assembly arranged in the side lock case. The side lock cylinder assembly includes a second button, a second gear, and a second spring. A plurality of protruding teeth is arranged on one side of the lock hook. The second gear is rotatably arranged in the side lock case. The second gear is capable of being engaged with the plurality of protruding teeth on the lock hook. The second button is rotatably arranged in the side lock case. The second spring is connected and arranged between the second button and the side lock case. One end of the second button is connected to the control mechanism through a cable. Under the action of the second spring, the other end of the second button is capable of being buckled on the teeth of the second gear. 
     Furthermore, the shock-absorbing wheel includes a wheel seat assembly and a roller. A lower part of the wheel seat assembly has a buffer cavity. A cushion pad is formed by secondary injection molding in the buffer cavity. A bottom of the buffer cavity is provided with a roller seat. The roller is mounted on the roller seat. 
     Furthermore, the wheel seat assembly includes an axle seat. A lower part of the axle seat extends backward to form a tailstock. The buffer cavity is arranged on the tailstock. The roller seat is connected to a lower part of the tailstock. 
     Furthermore, the cushion pad is provided with at least one buffer hole or at least one buffer groove. 
     Furthermore, the wheel seat assembly includes an axle seat. A middle part of the axle seat extends backward to form a rear seat. A lower part of the axle seat is pivotally connected to a swing shaft. The other end of the swing shaft extends downward relative to the rear seat and is connected to the roller seat. The buffer cavity is enclosed by the swing shaft, the roller seat and the rear seat. 
     Furthermore, the roller seat is supported on a main bearing surface of the bottom of the middle part of the cushion pad. A lift portion of a tail part of the rear seat is supported on a limit bottom surface of the bottom of the rear part of the cushion pad. An opening is formed between the roller seat and the lift portion. A protrusion at the bottom of the cushion pad is embedded into the opening. The swing shaft is supported on an auxiliary bearing surface at the bottom of the front part of the cushion pad. 
     As can be seen from the aforementioned technical solutions, the present invention has the following beneficial effects: 
     The trolley bag provided by the present invention utilizes shock-absorbing wheels, a multi-stage interlocking lock and separated hinge and middle frame structure. The trolley bag with a light and simple middle frame structure makes the trolley bag have a stable structure and not prone to deformation. With the shock-absorbing structure, pulling the luggage on walk will be smooth, and reducing the strength required by the human wrist. The multi-level interlocking structure makes it easier to close when the luggage is full, giving people a sense of lightness. The structure of the present invention is simple to assemble, and therefore saves labor costs. 
     The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings may also be obtained according to the provided drawings without creative efforts. 
         FIG. 1  is a schematic diagram of the three-dimensional structure of the present invention. 
         FIG. 2  is an exploded view of the present invention. 
         FIG. 3  is a schematic diagram of another three-dimensional structure of the present invention. 
         FIG. 4  is a schematic structural diagram of the connection between the hinge and the middle frame of the present invention. 
         FIG. 5  is a partial enlarged structural schematic diagram of X in  FIG. 4 . 
         FIG. 6  is a partial structural schematic diagram of the hinge of the present invention. 
         FIG. 7  is a schematic three-dimensional structure diagram of the hinge of the present invention. 
         FIG. 8  is a schematic structural diagram of the middle frame structure of the present invention. 
         FIG. 9  is a partial enlarged schematic view of the structure at Y in  FIG. 8 . 
         FIG. 10  is a schematic diagram of multiple middle frames being stacked and produced by injection molding at the same time. 
         FIG. 11  is a schematic structural diagram of the interlocking assembly of the present invention. 
         FIG. 12  is a schematic structural diagram of the interlocking assembly of the present invention when it is in an off state. 
         13  is an exploded view of the interlocking assembly of the present invention when it is in an off state. 
         FIG. 14  is a partial enlarged schematic view of the structure of  FIG. 12 . 
         FIG. 15  is a partial enlarged schematic view of the structure of  FIG. 13 . 
         FIG. 16  is a schematic structural diagram of the interlocking assembly of the present invention when it is in an on state. 
         FIG. 17  is a schematic diagram of the first structure of the shock-absorbing wheel of the present invention. 
         FIG. 18  is a schematic diagram of the first structure of the cushion pad of the shock-absorbing wheel of the present invention. 
         FIG. 19  is a schematic diagram of the second structure of the cushion pad of the shock-absorbing wheel of the present invention. 
         FIG. 20  is a schematic diagram of the third structure of the cushion pad of the shock-absorbing wheel of the present invention. 
         FIG. 21  is a schematic diagram of the second structure of the shock-absorbing wheel of the present invention. 
         FIG. 22  is a schematic diagram of the fourth structure of the cushion pad of the shock-absorbing wheel of the present invention. 
     
    
    
     In the drawings:  1 —top handle;  2 —trolley handle;  3 —back case;  4 —shock-absorbing wheel;  41 —wheel seat assembly;  411 —axle seat;  412 —buffer cavity;  413 —roller seat;  414 —tialstock;  415 —rear seat;  4151 —lift portion;  416 —swing shaft;  417 —opening;  42 —cushion pad;  42   a -first cushion pad;  42   b -second cushion pad;  42   c -third cushion pad;  42   d -fourth cushion pad;  421 —buffer hole;  422 —buffer groove;  423 —auxiliary bearing surface;  424 —main bearing surface;  425 —limit bottom surface;  426 —protrusion;  427 —recessed portion;  43 —roller;  5 —middle frame structure;  51 —middle frame;  51   a -first middle frame;  51   b -second middle frame;  511 —groove portion;  5111 —connecting groove;  5112 —baffle portion;  51121 —second inclined surface;  5113 —notch;  512 —second engagement portion;  5121 —slot;  5122 —snap hole;  513 —guide boss;  52 —hinge;  521 —connecting portion;  5211 —rib portion;  52111 —first inclined surface;  52112 —inclined guide portion;  522 —bushing;  5221 —axis hole;  523 —first engagement portion;  5231 —snap protrusion;  52311 —guide inclined surface;  524 —guide groove;  6 —side lock;  61 —side lock case;  611 —connecting seat;  62 —side lock cylinder assembly;  621 —second button;  6211 —second tooth slot portion;  6212 —third baffle surface;  6213 —fourth baffle surface;  622 —second gear;  623 —second spring;  7 —main lock;  71 —main lock case;  711 —lock seat;  712 —lock cover;  7121 —through hole;  713 —first cover;  714 —second cover;  72 —main lock cylinder assembly;  721 —first button;  7211 —first tooth slot portion;  7212 —first baffle surface;  7213 —second baffle surface;  722 —first gear;  723 —first spring;  73 —control mechanism;  731 —pusher;  7311 —push torque;  7311 —top plate portion;  7312 —rack portion;  7313 —tail surface;  7314 —first indication surface;  7315 —second indication surface;  732 —reduction gear;  7321 —gear wheel;  7322 —pinion;  733 —first rack;  734 —second rack;  735 —ball plunger;  736 —ball plunger spring;  737 —custom lock;  7371 —press plate;  738 —cable;  7381 —external pipe sleeve;  7382 —core cable;  8 —lock hook;  81 —protrusion tooth;  9 —front case;  10 —vertical stripe;  11 —first diagonal stripe;  12 —second diagonal stripe. 
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims. 
     The present invention will be further described below with reference to  FIG. 1  to  FIG. 22 . As shown in  FIG. 1 ,  FIG. 2 , and  FIG. 3 , a trolley with separated middle frame and hinge and having shock-absorbing structure includes a trolley handle  2 , a rear case  3 , a middle frame structure  5 , and a front case  9 . The middle frame structure  5  includes two sets of hinge structures and a pair of middle frames  51 . The two middle frames  51  are the first middle frame  51   a  and the second middle frame  51   b . The first middle frame  51   a  is connected to the rear case  3 , and the second middle frame  51   b  is connected to the front case  9 . The hinge structure includes a pair of hinges  52  and a core pin. One of the hinges  52  is connected to the first middle frame  51   a , and the other one of the hinges  52  is connected to the second middle frame  51   b . The hinge  52  is movably connected by a core pin, and can be swung in 180 degrees. The pair of middle frames  51  are locked by interlocking assembly. The four corners of the bottom of the trolley bag are provided with shock-absorbing wheels  4 . The trolley handle  2  is installed on the rear case  3 . The top of the rear case  3  is provided with a top handle  1 , and the side of the front case  9  is provided with a top handle  1 . 
     As shown in  FIG. 4 ,  FIG. 5 ,  FIG. 6 , and  FIG. 7 , the hinge  52  has a connecting portion  521 , and a plurality of rib portions  5211  are provided on one side wall of the connecting portion  521  at intervals along the length direction of the connecting portion  521 . The other side wall of the connecting portion  521  is provided with a plurality of rib portions  5211  at intervals along the length direction of the connecting portion  521 . The rib portions  5211  on the two side walls of the connecting portion  521  are staggered. The middle frame  51  is provided with a groove portion  511 . The bottom surface of the groove portion  511  is provided with a connecting groove  5111 , and the side wall of the connecting groove  5111  is provided with a baffle portion  5112  matched with the rib portion  5211 . A notch  5113  is formed on the rear side of each baffle portion  5112  corresponding to the rib portion  5211 . When the hinges  52  are installed on the middle frames  51 , the bottom surface of the baffle portion  5112  abuts the top surface of the rib portion  5211 . The top of the connecting portion  521  is connected to a plurality of bushings  522  at equal intervals along the length direction thereof. The bushings  522  are provided with an axis hole  5221  which is adapted to the core pin. The core pin alternately passes through the bushings  522  of the pair of hinges  52  to hinge the pair of hinges  52 . In addition, the front end of the connecting portion  521  is connected to the first engaging portion  523 . A second engaging portion  512  is provided on the middle frame  51  on the front side of the groove portion  511 . A slot  5121  is defined on the second engaging portion  512 . The top of the slot  5121  defines a snap hole  5122  penetrating the top surface of the second locking portion  512 . The top of the first engagement portion  523  is provided with a snap protrusion  5231  which is matched with the snap hole  5122 . 
     During installation, the rib portion  5211  on the connecting portion  521  is aligned with the notch  5113  to install the connecting portion  521  into the connecting groove  5111 . Then, the hinge  52  is pushed along the length direction of the connecting groove  5111 , so that the rib portion  5211  on the hinge  52  is moved to the right under the corresponding baffle portion  5112 , so that the bottom surface of the baffle portion  5112  abuts the top surface of the rib portion  5211 . In addition, during the process of pushing the hinge  52 , the first engaging portion  523  is inserted into the slot  5121 , and finally the snap protrusion  5231  is inserted into the engaging hole  5122 , so that the hinge  52  and the middle frame  51  are connected reliably. 
     Preferably, as shown in  FIG. 6 , a guide inclined surface  52311  is provided on the front side of the top of the snap protrusion  5231 . The front end of the rib portion  5211  is provided with an inclined guide portion  52112 . 
     Preferably, as shown in  FIG. 8  and  FIG. 9 , the top surface of the rib portion  5211  is a first inclined surface  52111  which is provided obliquely. The bottom surface of the stopper portion  5112  is a second inclined surface  51121  which is provided obliquely. The included angle between the second inclined surface  51121  and the side wall of the connecting groove  5111  is an acute angle. When the hinges  52  are installed on the middle frames  51 , the second inclined surface  51121  abuts against the first inclined surface  52111 , so that the fixed connection between the hinge  52  and the middle frame  51  is more reliable. 
     Preferably, as shown in  FIG. 8  and  FIG. 9 , the bottom of the connecting groove  5111  is provided with a guide boss  513 . A guide groove  524  extending through the front and rear surfaces of the guide groove  524  is defined on the bottom wall of the hinge  52  along the longitudinal direction of the hinge  52 . The guide groove  524  is slidably matched with the guide boss  513 . 
     As shown in  FIG. 10 , the hinge  52  is detachably connected to the middle frame  51 , so that the middle frame  51  does not have the limitation of core pulling of the hinge in the prior art, so that the middle frame  51  can be produced in stacks and the simultaneous injection molding in production can be realized, accordingly the molding efficiency of the middle frame  51  is improved. 
     As shown in  FIG. 2  and  FIG. 11 , the interlocking lock assembly includes a main lock  7  and a pair of side locks  6  interlocked with the main lock  7 . The main lock  7  is arranged on the side of the first middle frame  51   a  opposite to the side where the hinge structure is located. The main lock  7  includes a main lock case  71 , a control mechanism  73  and a pair of main lock cylinder assemblies  72 . The control mechanism  73  and a pair of main lock cylinder assemblies  72  are both disposed in the main lock case  71 . In addition, a pair of main lock cylinder assemblies  72  are respectively located on both sides of the control mechanism  73 . One side lock  6  is arranged on the upper side of the first middle frame  51   a , and the other side lock  6  is arranged on the lower side of the first middle frame  51   a . Four lock hooks  8  are provided on the second middle frame  51   b . A number of protruding teeth  81  are provided on one side of the lock hook  8 . The control mechanism  73  can control the on and off of the pair of side locks  6  while controlling the on and off of the pair of main lock cylinder assemblies  72 . 
     As shown in  FIG. 12 ,  FIG. 13  and  FIG. 15 , the main lock case  71  includes a lock seat  711 , a lock cover  712 , a first cover  713  and a second cover  714  connected to the lock seat  711 . A main lock cavity is formed between the first cover  713  and the second cover  714  and the lock seat  711  respectively. Control mechanism  73  includes a drive assembly and a customs lock  737 . The customs lock  737  is installed inside the lock cover  712 . The drive assembly is provided in the main lock case  71 . Specifically, the drive assembly includes a pusher  731 , a pair of reduction gears  732 , a first rack  733  and a second rack  734 . The pusher  731  is slidably disposed in the main lock case  71 . In addition, the push torque  7311  of the pusher  731  is slidably matched with the through hole  7121  on the lock cover  712 . Moreover, the push torque  7311  protrudes from the through hole  7121  on the lock cover  712 . A top plate portion  7311  is provided on the top of the pusher  731 . A rack portion  7312  is provided at the lower portion of the top plate portion  7311 . A gear wheel  7321  of a reduction gear  732  meshes with the rack portion  7312 . The pinion gear  7322  on the reduction gear  732  meshes with the gear wheel  7321  of the other reduction gear  732 . The first rack  733  is slidably arranged in the main lock case  71 . The first rack  733  meshes with the pinion  7322  on the other reduction gear  732 . The first rack  733  is connected with a main lock cylinder assembly  72 . The second rack  734  is slidably arranged in the main lock case  71 . The second rack  734  meshes with the pinion  7322  on the other reduction gear  732 . The second rack  734  is connected with the other main lock cylinder assembly  72 . 
     As shown in  FIG. 12 ,  FIG. 13 , and  FIG. 14 , the main lock cylinder assembly  72  includes a first button  721 , a first gear  722  and a first spring  723 . The first gear  722  is rotatably arranged in the main lock cavity of the main lock case  71 . The first gear  722  can engage with several protruding teeth  81  on the lock hook  8 . The first button  721  is rotatably arranged in the main lock cavity of the main lock case  71 . One end of the first button  721  is provided with a tooth groove portion  7211  on the side adjacent to the first gear  722 . The other end of the first button  721  is movably connected with the first rack  733  or the second rack  734 . The first spring  723  is connected and arranged between the other end of the first button  721  and the first rack  733  or the second rack  734 . Under the action of the elastic force of the first spring  723 , the tooth groove portion  7211  of the first button  721  can be snapped and connected to the teeth of the first gear  722 . The first baffle surface  7212  and second baffle surface  7213  of the first button  721  are against the first gear  722 , so that the first gear  722  cannot be reversed. 
     As shown in  FIGS. 13 and 14 , the side lock  6  includes a side lock case  61  and a side lock cylinder assembly  62  disposed in the side lock case  61 . The side lock cylinder assembly  62  includes a second button  621 , a second gear  622  and a second spring  623 . The second gear  622  is rotatably arranged in the side lock case  61 . The second gear  622  can engage with several protruding teeth  81  on the lock hook  8 . The second button  621  is rotatably arranged in the side lock case  61 . One end of the second button  621  is provided with a second tooth slot portion  6211  on the side adjacent to the second gear  622 . The other end of the second button  621  is connected to the first rack  733  or the second rack  734  through a cable  738 . The second spring  623  is connected and arranged between the second button  621  and the connecting seat  611  of the side lock case  61 . Under the action of the second spring  623 , the second tooth groove portion  6211  of the second button  621  is engaged with the teeth of the second gear  622 , and the third surface  6212  and the fourth surface  6213  of the second button  621  are against the second gear  622 , so that the second gear  622  cannot be reversed. 
     Preferably, as shown in  FIG. 13 ,  FIG. 14 , and  FIG. 15 , the main lock  7  further includes a ball plunger  735  and a ball plunger spring  736 . The ball plunger  735  is movably arranged in the main lock case  71 . The ball plunger spring  736  is provided between the ball plunger  735  and the main lock case  71 . The pusher  731  is provided with a first indication hole  7314  and a second indication hole  7315  which are matched with the ball plunger  735 . When in use, the ball plunger  735  is pressed against the pusher  731  by the push force of the ball plunger spring  736 , so that the pusher  731  will not move freely. When the ball plunger  735  is fastened on the second indication hole  7315  of the pusher  731 , the pusher  731  is kept open by the elastic force of the ball plunger spring  736 . In addition, when the ball plunger  735  collides with the pusher  731  under the elastic force of the ball plunger spring  736 , a crisp sound will be generated, so that the user can know that the switch is in place by feeling the feedback of the sound. 
     As shown in  FIG. 14 , the cable  738  includes a core cable  7382  and an external sleeve  7381  sheathed outside the core cable  7382 . One end of the external sleeve  7381  is connected to the connecting seat  611  of the side lock case  61 . The other end of the external sleeve  7381  is connected to the main lock case  71 . One end of the core cable  7382  is connected to the second button  621 . The other end of the core cable  7382  is connected to the first rack  733  or the second rack  734 . 
     As shown in  FIG. 3 ,  FIG. 12  and  FIG. 16 , when the pusher  731  is in the off state, the trolley bag is closed, and the lock hook  8  on the second middle frame  51   b  drives the first gear  722  of the main lock cylinder assembly  72  to rotate, and the first gear  722  rotates to force the first button  721  to overcome the elastic force of the first spring  723 . After the lock hook  8  buckles the next level, the first button  721  will be fastened by the force of the first spring  723  to fasten the first gear  722 , and a collision sound will be generated at the same time, so that the user knows the lock hook  8  is in place. At the same time, the lock hook  8  will also drive the second gear  622  of the side lock cylinder assembly  62  to rotate, and the rotation of the second gear  622  forces the second button  621  to overcome the elastic force of the second spring  623 , and the lock hook  8  locks the second button  621  after the next level. The second gear  622  will be fastened by the force of the second spring  623 , and a collision sound will be generated to let the user know that the lock hook  8  is fastened. Because the first button  721  is pushed by the first spring  723 , the first baffle surface  7212  and the second baffle surface  7213  of the first button  721  stand against the first gear  722 , so that the first gear  722  cannot be reversed. Since the second button  621  is pushed by the second spring  623 , the third baffle surface  6212  and the fourth baffle surface  6213  of the second button  621  stand against the second gear  622 , so that the second gear  622  cannot be reversed, and the trolley bag is closed. At the same time, the contact ball  735  is pressed against the pusher  731  by the thrust force of the ball plunger spring  736 , so that the pusher  731  will not move freely. When the user closes the customs lock  737 , the pressing piece  7371  of the customs lock  737  bears against the rear surface  7313  of the pusher  731 , so that the lock is in a closed state. When the user needs to open the trolley bag, push the pusher  731 . The pusher  731  drives the gear wheel  7321  of the reduction gear  732  to rotate, and the pinion  7322  on the reduction gear  732  drives the gear wheel  7321  of the other reduction gear  732  to rotate, so that the pinion  7322  on the other reduction gear  732  drives the first rack  733  and the second rack  734  move, further make first rack  733  and second rack  734  drive the corresponding first button  721  to rotate, so that first button  721  is separated from first gear  722 , so that first gear  722  can rotate freely, thereby making the lock The hook  8  can be freely disengaged from the main lock  7 . At the same time, the first rack  733  and the second rack  734  drive the corresponding cables  738  to move, so that the second button  621  is separated from the second gear  622 , so that the second gear  622  can rotate freely, so that the lock hook  8  can be free from the side lock  6 , and the bag is opened. 
     In addition, the number of side locks  6  can also be increased or decreased according to the size of the trolley bag. 
     As shown in  FIG. 17  and  FIG. 18 , the shock-absorbing wheel  4  includes a wheel seat assembly  41  and a pair of rollers  43 . Wheel seat assembly  41  includes axle seat  411 . The lower part of the axle seat  411  extends backward to form a tailstock  414 . A roller seat  413  is connected to the lower part of the tailstock  414 . A buffer cavity  412  is formed between the tailstock  414  and the roller seat  413 . In the buffer cavity  412 , a cushion pad  42  is formed by secondary injection molding. The cushion pad  42  is the first cushion pad  42   a . The first cushion pad  42   a  is made of soft rubber. The roller seat  413  sinks into the recessed portion  427  of the first cushion pad  42   a . A pair of rollers  43  are mounted on the roller seat  413 . When the shock-absorbing wheel  4  rotates and falls, the punched first cushion pad  42   a  has the effect of shock-absorbing, which more effectively protects the trolley bag, and the assembly is simple and cost-saving. 
     Preferably, as shown in  FIG. 18 , a guide boss is provided on the inner peripheral wall of the buffer cavity  412 . The outer periphery of the first cushion pad  42   a  is provided with a positioning groove matched with the positioning boss. 
     In another embodiment, as shown in  FIG. 19 , the cushion pad  42  is the second cushion pad  42   b . The difference between the second cushion pad  42   b  and the first cushion pad  42   a  is that the second cushion pad  42   b  is provided with three buffer holes  421 . Both ends of the buffer hole  421  penetrate through the two side walls of the second cushion pad  42   b . Among them, two buffer holes  421  are round holes, and one buffer hole  421  is a special-shaped hole in a meniscus shape. The buffer holes  421  are added according to the size of the trolley bag so as to enhance the buffer effect. 
     In another embodiment, as shown in  FIG. 20 , the cushion pad  42  is a third cushion pad  42   c . The difference between the third cushion pad  42   c  and the first cushion pad  42   a  is that a buffer groove  422  is formed on the side wall of the third cushion pad  42   c . The buffer groove  422  is a special-shaped groove, and the buffer groove  422  is added according to the size of the trolley bag, so as to enhance the buffer effect. 
     In another embodiment, as shown in  FIG. 21  and  FIG. 22 , the shock-absorbing wheel  4  includes a wheel seat assembly  41 , a cushion pad  42  and a pair of rollers  43 . The wheel seat assembly  41  includes a mounting seat and an axle seat  411 . The upper end of the shaft seat  411  is rotatably connected with the mounting seat. The middle portion of the axle seat  411  extends backward to form a rear seat  415 . A swing shaft  416  is pivotally connected to the lower part of the shaft seat  411 . The other end of the swing shaft  416  extends below the rear seat  415  and is connected with a roller seat  413 . A buffer cavity  412  is formed between the swing shaft  416 , the roller seat  413  and the rear seat  415 . The cushion pad  42  is a fourth cushion pad  42   d . The fourth cushion pad  42   d  is embedded in the buffer cavity  412 . The roller seat  413  abuts against the main bearing surface  424  at the bottom of the middle portion of the fourth cushion pad  42   d . The lift portion  4151  at the rear of the rear seat  415  abuts against the limit bottom surface  425  at the bottom of the rear portion of the cushion pad  42   d . An opening  417  is formed between the roller seat  413  and the lift portion  4151 . The protrusions  426  at the bottom of the fourth cushion pad  42   d  are embedded in the openings  417 . The swing shaft  416  abuts against the auxiliary bearing surface  423  at the bottom of the front part of the fourth cushion pad  42   d . The cushion pad  42   d  is made of soft rubber material. During assembly, the wheel seat assembly  41  and the swing shaft  416  are first connected together. Then, the fourth cushion pad  42   d  is injection-molded, so that the middle of the wheel seat assembly  41  and the swing shaft  416  is combined with the fourth cushion pad  42   d . A pair of rollers  43  are installed on the roller seat  413 , so that when the shock-absorbing wheel  4  rotates and falls, the stamping cushion pad  42   d  has the effect of shock-absorbing, preventing the impact from directly acting on the trolley bag, effectively protecting the trolley bag case, and simple assembly and cost saving. 
     Preferably, as shown in  FIG. 1 , the rear case  3  is provided with vertical stripes  10 , a first diagonal stripes  11 , and second diagonal stripes  12  protruding from the outer surface of the rear case  3 . The front case  9  is also provided with vertical stripes  10 , first diagonal stripes  11  and second diagonal stripes  12  that protrude from the outer surface of the rear case  3 . Exquisite patterns are formed on the outer surface, making the trolley bag beautiful in appearance. 
     As shown in  FIG. 2  and  FIG. 3 , when in use, the push button  721  is pushed, and the plurality of lock hooks  8  of the trolley bag simultaneously turn on. At this point, the trolley bag can be swung to between opened and closed state in 180 degrees. When the trolley bag is full of luggage, the lock hook  8  can adjust the closing distance so that the trolley bag can be easily closed. In addition, the wheel seat assembly  41  of the installed shock-absorbing wheel  4  uses the soft rubber injection molding to produce a buffer effect to realize the shock-absorbing function, which reduces the shaking of the trolley bag during walk. With the middle frame structure, the trolley bag is more stable, which improves the deformation of the conventional trolley bag when it is full of luggage, which makes it difficult to drag and walk. In addition, the hinge  52  and the middle frame  51  are separated and connected by a buckle structure, which eliminates the need for screw fastening and makes the assembly easier. This reduces labor costs, and the separation of the hinge  52  and the middle frame  51  reduces the molding cycle of the middle frame  51 . At the same time, the mold of the middle frame  51  is simplified, so that the mold of the middle frame  51  can be produced by stacking, which improves the molding efficiency of the middle frame  51 , and the assembly is simple, reliable, and cost-saving. 
     The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.