Patent Publication Number: US-10777032-B2

Title: Method and device for correcting deviation of paper medium, and financial self-service device

Description:
This application is the national phase of International Application No. PCT/CN2016/080652, titled “METHOD AND DEVICE FOR CORRECTING DEVIATION OF PAPER MEDIUM, AND FINANCIAL SELF-SERVICE DEVICE”, filed on Apr. 29, 2016 which claims the benefit of priority to Chinese patent application No. CN201510448112.8 titled “METHOD AND DEVICE FOR CORRECTING PAPER MEDIUM SKEW AND FINANCIAL SELF-SERVICE APPARATUS”, filed with the Chinese State Intellectual Property Office on Jul. 27, 2015, the entire disclosures of which applications are incorporated herein by reference. 
     FIELD 
     The present application relates to a conveying auxiliary device for a paper medium, and more specifically to a conveying device for correcting skew of valuable paper mediums such as banknotes and checks. 
     BACKGROUND 
     The ATMs, cash counters and other paper medium conveying devices are all required to be equipped with a skew correcting device integrated with the conveying device in order to ensure that banknotes and other valuable paper mediums are conveyed in the machine tidily without being skewed. A skew correcting mechanism in the conventional technical solution has a guiding device for guiding horizontal movement of banknotes, a driving roller for providing power to the movement of banknotes, a pinch roller in contact with the banknotes and performing skew correction and a supporting frame thereof, and other accessories. The conventional device has disadvantages of a large size, difficult adjusting of the skew correcting force, being apt to over-correct the skew of old banknotes, and further causing jam of the valuable banknotes in the device, which adversely affects the utilization efficiency of the conveying device seriously, and is extremely apt to cause damage of the banknotes due to the jam of the banknotes in the device, and increases extra loss. 
     In view of the disadvantages of the conventional skew correcting device, the technical solution in the invention of “SKEW CORRECTING MECHANISM” with the application number of 20051121474.2 has a correcting force adjusting device added on the basis of the conventional solutions and can relatively freely adjust the correcting force acting on the paper mediums, and overcome the deficiency of a constant correcting force in the conventional technical solutions; the technical solution in the invention of “AUTOMATIC TELLER MACHINE AND SKEW CORRECTING DEVICE THEREOF” with the application number of 201310143787.2 includes a banknote movement track consisting of two layers of passage plates, a driving roller, a skew correction adjusting roller and a transmission device thereof. The skew correction function for banknotes is achieved by cooperation of a reference wall, the skew correction adjusting roller and the driving roller, thus achieving a direct effect of the skew correcting roller to the banknotes and reducing a transmitting space for correcting skew of banknotes, and reducing the size of the device significantly. 
     Although the solution in the existing patents can perform correction of skewed paper mediums in conveyance, the technical solution has disadvantages of a complex structure and more parts and components, and high manufacturing and assembling costs. 
     SUMMARY 
     In order to address the issues of complex structure and high manufacturing costs of the skew correcting device in the conventional technology, a paper medium skew correcting device and a financial self-service apparatus are provided according to the present application, which can effectively correct and convey skewed mediums, while ensuring the reliability of the device, simplifies the structure of the device and reduces manufacturing and assembling costs of the device as much as possible, and also minimizes the size of the device as much as possible to facilitate the integration of the device in ATMs and cash counters. 
     A paper medium skew correcting method is further provided according to the present application. 
     A paper medium skew correcting device according to the present application includes: a support including a pair of fixed stop plates arranged in parallel and configured to fixedly mount the following components; a skew correcting tapered roller assembly including a tapered roller, a reference plate located at a large end face of the tapered roller, and a tapered roller transmission shaft, specifically, the skew correcting tapered roller assembly is fitted to transmission shaft mounting holes of the pair of fixed stop plates on a left side and a right side by the tapered roller transmission shaft; a tapered cover plate covering on the tapered roller, with a paper medium skew correcting passage formed between an inner wall of the tapered cover plate and an outer wall of the tapered roller, specifically, an auxiliary pressure roller mechanism is mounted on an outer wall of the tapered cover plate, and is configured to press a paper medium in the skew correcting passage against the outer wall of the tapered roller tightly, the tapered cover plate is provided with an opening for the auxiliary pressure roller mechanism to elastically press the tapered roller tightly; and a driving transmission assembly, for providing power to the tapered roller. 
     Preferably, the paper medium skew correcting device further includes an entrance leading passage. The entrance leading passage includes a horizontal passage interface and an inclined turning passage, an inner wall of the inclined turning passage is a smooth curved surface and is tangentially connected to an inner wall of the horizontal passage and the inner wall of the tapered cover plate. 
     Further, the entrance leading passage further includes a driving banknote picking roller, a guide driven pinch roller and a turning driven roller in the listed sequence in the conveying direction of paper medium. The driving banknote picking roller is connected to the pair of fixed stop plates on the two sides by a fixed shaft, the driving banknote picking roller is in contact with the guide driven pinch roller through a roller slot in the horizontal passage interface, and the turning driven pinch roller is connected to the pair of fixed stop plates on the two sides by an inclined shaft, and the turning driven pinch roller is in contact with the tapered roller through a roller slot in the inclined turning passage. 
     Preferably, the paper medium skew correcting device further includes an exit transfer passage. The exit transfer passage includes a horizontal turning passage and an outward transfer horizontal passage, an inner wall of the horizontal turning passage is a smooth curved surface and is tangentially connected to the inner wall of the tapered cover plate and the outward transfer passage. 
     Further, the exit transfer passage further includes a driving delivery roller and a slant driven pinch roller, the driving delivery roller is connected to the pair of fixed stop plates on the left side and the right side by a shaft, and the driving delivery roller is in contact with an inner wall of the outward transfer horizontal passage through a roller slot in the outward transfer horizontal passage; and the slant driven pinch roller is connected to the pair of fixed stop plates on the left side and the right side by an inclined shaft; and the slant driven pinch roller is in contact with the tapered roller through a roller slot in the tapered cover plate. 
     Preferably, the auxiliary pressure roller mechanism includes a pressure roller seat and an auxiliary pressure roller, a pressure roller shaft and a pressing force adjusting spring, and the auxiliary pressure roller mechanism is mounted to a fitting hole in the tapered cover plate via the pressure roller seat, and the auxiliary pressure roller is in contact with the tapered roller through a roller slot in the tapered cover plate, and the pressing force adjusting spring has one end fixed to the pressure roller seat and another end connected to the auxiliary pressure roller, and the pressing force adjusting spring is configured to adjust the pressure of the auxiliary pressure roller acting on the tapered roller. 
     A paper medium skew correcting method according to the present application, includes: 
     step 1, entering a paper medium to be corrected into the entrance leading passage of the above paper medium skew correcting device, and entering the paper medium into the paper medium skew correcting passage between the tapered cover plate and the tapered roller via the horizontal passage interface and the inclined turning passage; 
     step 2, sliding, by a co-action of a centrifugal force and a rotational kinetic friction force of the tapered roller, the paper medium towards a large end of the tapered roller, and when an edge of the paper medium fits the large end surface reference plate, the paper medium stops moving axially due to being blocked by the large end surface reference plate, thus achieving the skew correction to the paper medium during conveying and moving process; and 
     step 3, entering the paper medium into the outward transfer passage via the horizontal turning passage, thus outputting the skew-corrected paper medium. 
     Preferably, in step 1, the paper medium in the horizontal passage interface enters the inclined turning passage under the action of the driving banknote picking roller and the guide driven pinch roller, and then enters the paper medium skew correcting passage between the tapered cover plate and the tapered roller under the action of the turning driven pinch roller; and in step 3, when the paper medium enters the horizontal turning passage from the skew correcting passage, the slant driven pinch roller acts on the paper medium to prevent the paper medium from being skewed again, and the driving delivery roller provides power to realize the output of the skew-corrected paper medium. 
     Preferably, in step 2, the auxiliary pressure roller mechanism acts on the surface of the tapered roller, to apply a pressure on the paper medium passing through the paper medium skew correcting passage and guide the paper medium, to prevent the paper medium from separating from the outer surface of the tapered roller due to the action of the centrifugal force generated when the paper medium moves in the skew correcting passage. 
     A financial self-service apparatus is further provided according to the present application, which includes: a banknote access slot for depositing and/or withdrawing of banknotes; a banknote receiving box for storing banknotes; and a banknote conveying passage configured to connect the banknote access slot and the banknote receiving box and convey banknotes. The banknote conveying passage is provided with the above paper medium skew correcting device. 
     The paper medium skew correcting device according to the present application has the following beneficial effects compared with the conventional skew correcting device. 
     The paper medium skew correcting device according to the present application adopts the tapered roller assembly to achieve skew correction of banknotes. The tapered roller and the tapered cover plate in the tapered roller assembly cooperate to form the paper medium skew correcting passage. The power for movement of banknotes in the skew correcting passage is only provided by the driving transmission assembly. Since the skew correcting passage formed by the tapered roller and the tapered cover plate is around the tapered roller, the skew correcting passage does not occupy a large space in a horizontal direction, and the tapered roller has a simple structure, and is easy to assemble. Therefore, the paper medium skew correcting device according to the present application effectively simplifies the structure, reduces the manufacturing and assembling costs of the products, and fully utilizes the co-action of the centrifugal force and friction force generated in the movement of the paper medium along with the tapered roller to achieve skew correction and conveyance of the paper medium, thereby fundamentally overcoming the technical issue of jam of valuable paper medium in the device due to a too large skew correcting force. Also, since the structure is simplified, the device can effectively reduce the volume, and facilitates the integration of the device in other apparatuses such as the ATMs and cash counters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a financial self-service apparatus having a skew correcting device; 
         FIG. 2  is a schematic perspective view showing the structure of a paper medium skew correcting device according to a preferred embodiment of the present application; 
         FIG. 3  is an enlarged view of a part F in  FIG. 1 ; 
         FIG. 4  is a side view of the paper medium skew correcting device in  FIG. 1 ; 
         FIG. 5  is a bottom view of the paper medium skew correcting device in  FIG. 1 ; 
         FIG. 6  is a schematic perspective view showing the structure of a tapered roller of the paper medium skew correcting device in  FIG. 1 ; 
         FIG. 7  is a schematic perspective view showing the structure of a tapered cover plate of the paper medium skew correcting device in  FIG. 1 ; and 
         FIG. 8  is a side view of an inclined turning passage of the paper medium skew correcting device in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The components of the paper medium skew correcting device and the working principle thereof are described hereinafter with reference to the drawings. 
     As shown in  FIG. 1 , which is a schematic view of the components of a financial self-service apparatus according to the present application, the financial self-service apparatus includes a banknote access slot  01  for depositing and/or withdrawing banknotes, a banknote receiving box  03  for storing banknotes, a banknote conveying passage  02  which connects the banknote access slot  01  and the banknote receiving box  03  to convey banknotes. The banknote conveying passage  02  is provided with a paper medium skew correcting device  04  capable of correcting banknote skew in the banknote conveying passage. The financial self-service apparatus further includes an identification module for identifying banknotes and a necessary control module (not illustrated), and all of these modules are the same as related modules of a conventional financial apparatus, and are not described here. 
     As shown in  FIG. 2  and  FIG. 4 , a paper medium skew correcting device  04  according to this embodiment includes a support, an entrance leading passage  13 , an exit transfer passage  14 , a skew correcting tapered roller assembly, a tapered cover plate  4  and a driving transmission assembly  3 , an outer wall of the tapered cover plate  4  is mounted with an auxiliary pressure roller mechanism  16 . 
     The support includes a pair of fixed stop plates  11  and  12  arranged in parallel and at least one stop plate supporting shaft  15  located between the pair of fixed stop plates for supporting the pair of fixed stop plates. The support is a supporting frame for the paper medium skew correcting device, and other parts and components are arranged between the pair of fixed stop plates  11 ,  12  or fixed on one of the fixed stop plates. The driving transmission assembly  3  is arranged at an outer side of the stop plate  12  for providing power to the paper medium skew correcting device. The driving transmission assembly  3  includes a driving motor  31 , a synchronous belt  32 , a driving synchronous pulley  33 , a tapered roller synchronous pulley  34 , a tensioning guide synchronous pulley  35 , a driving banknote picking pulley  36 , a driving banknote conveying pulley  37  and at least one motor supporting shaft  38 . 
     The entrance leading passage  13  includes a horizontal passage interface  131 , an inclined turning passage  132 , a driving banknote picking roller  133 , a guide driven pinch roller  134 , and a turning driven roller  135  in the listed sequence in a paper medium conveying direction. The horizontal passage interface  131  and the inclined turning passage  132  are connected to the fixed stop plates  11  and  12  on the two sides by screws. The driving banknote picking roller  133  is connected to the fixed stop plates  11  and  12  on the two sides by a fixed shaft, and the driving banknote picking roller  133  is in contact with the guide driven pinch roller  134  via a roller slot in the horizontal passage interface  131 . The turning driven pinch roller  135  is connected to the fixed stop plates  11 ,  12  on the left and right sides through an inclined shaft, and the turning driven pinch roller  135  is in contact with the tapered roller  21  through a roller slot in the inclined turning passage  132 . 
     The exit transfer passage  14  includes a horizontal turning passage  141 , an outward transfer horizontal passage  142 , a driving delivery roller  143  and a slant driven pinch roller  144 . The horizontal turning passage  141  and the outward transfer horizontal passage  142  are connected to the fixed stop plates  11  and  12  on the two sides by screws. The driving delivery roller  143  is connected to the fixed stop plates  11  and  12  on the left and right sides by a shaft. The driving delivery roller  143  is in contact with an inner wall of the outward transfer horizontal passage  142  through a roller slot in the outward transfer horizontal passage  142 . The slant driven pinch roller  144  is connected to the fixed stop plates  11 ,  12  on the left and right sides through an inclined shaft; and the slant driven pinch roller  144  is in contact with the tapered roller  21  through a roller slot  41  in the tapered cover plate  4 . 
     As shown in  FIG. 5  and  FIG. 6 , the skew correcting tapered roller assembly is located between the entrance leading passage  13  and the exit transfer passage  14 , and includes a tapered roller  21 , a large end face reference plate  222  and a small end face reference plate  221  located on two ends of the tapered roller and a tapered roller transmission shaft  23 . The skew correcting tapered roller assembly is fitted and connected to transmission shaft mounting holes of the pair of fixed stop plates  11  and  12  on the left and right sides by the tapered roller transmission shaft  23 . 
     As shown in  FIG. 7 , the tapered cover plate  4  has a shape as illustrated by the figure, the two sides of the tapered cover plate  4  are fixedly connected to the pair of fixed stop plates  11 ,  12  respectively, the tapered cover plate  4  covers the tapered roller  21 , and a gap between an inner wall of the tapered cover plate  4  and an outer wall of the tapered roller  21  forms a paper medium skew correcting passage. At an entrance side in the paper medium conveying direction, as shown in  FIG. 8 , an inner wall of the inclined turning passage  132  is a smooth curved surface, and the inclined turning passage  132  has one side connected to the horizontal passage interface  131  and another side connected to the tapered roller  21 . The inclined turning passage  132  is configured to connect the horizontal passage interface  131  to the paper medium skew correcting passage. Similarly, at an exit side in the paper medium conveying direction, an inner wall of the horizontal turning passage  141  is a smooth curved surface, and the horizontal turning passage  141  has one side connected to the tapered cover plate  4  and another side connected to the outward transfer horizontal passage  142 . The horizontal turning passage  141  is configured to connect the paper medium skew correcting passage to the outward transfer horizontal passage  142 . In addition, in order to ensure the smooth movement of the paper mediums, the inner smooth curved surface of the inclined turning passage  132  is tangent to the inner curved surface of the horizontal passage interface  131  at a position where the inclined turning passage is connected to the horizontal passage interface  131 . The smooth curved surface of the inner wall of the inclined turning passage  132  is tangent to a curved surface of the inner wall of the tapered cover plate  4  at a position where the inclined turning passage is connected to the tapered roller  21 . Similarly, in order to ensure the smooth movement of the paper mediums, the smooth curved surface of the inner wall of the horizontal turning passage  141  is tangent to the inner wall of the tapered cover plate  4  at a position where the horizontal turning passage is connected to the tapered cover plate  4 , the smooth curved surface of the inner wall of the horizontal turning passage  141  is tangent to the inner wall of the outward transfer passage  142  at a position where the horizontal turning passage is connected to the outward transfer passage  142 . 
     Referring to  FIG. 2  and  FIG. 3 , the auxiliary pressure roller mechanism  16  is configured to press the paper medium in the skew correcting passage against an outer wall of the tapered roller  21 , and the tapered cover plate  4  is provided with an opening for the auxiliary pressure roller mechanism  16  to elastically press against the tapered roller  21 , that is, the roller slot  41 . The auxiliary pressure roller mechanism  16  includes a pressure roller seat  161 , a pair of auxiliary pressure rollers  162  arranged symmetrically, a pair of pressure roller shafts  163 , a pair of pressure roller brackets  164 , and a pair of pressing force adjusting springs  165 . The auxiliary pressure roller mechanism  16  is mounted to a fitting hole in the tapered cover plate  4  by the pressure roller seat  161 . In this embodiment, the pair of symmetrical auxiliary pressure rollers  162  is provided, therefore, the pressure roller seat has a z-shaped structure. Each of two ends of the Z-shaped structure is provided with one pressure roller shaft  163 , and the pressure roller bracket is pivoted on the pressure roller shaft  163 , and the auxiliary pressure roller  162  is mounted to a terminal end of the pressure roller bracket. The auxiliary pressure roller  162  is in contact with the tapered roller  21  through the roller slot  41  in the tapered cover plate  4 . The pressure adjusting spring  165  has one end fixed to the pressure roller seat  161  and another end connected to the auxiliary pressure roller  162 . The pressing force adjusting spring  165  is configured to adjust the pressure of the auxiliary pressure roller  162  acting on the tapered roller  21 . The paper medium, when moving in the skew correcting passage, may be pressed and guided by the auxiliary pressure rollers  162  of the auxiliary pressure roller mechanism  16 , thus may prevent the paper medium from separating from the surface of the tapered roller  21  due to a centrifugal effect of the movement in the skew correcting passage. 
     The process of correcting the paper medium skew by the paper medium skew correcting device is described as follows. The paper medium enters the horizontal passage interface  131  in the entrance leading passage  13  from other modules. Since it is required to turn by a certain angle when entering from the horizontal passage interface  131  to the paper medium skew correcting passage between the tapered cover plate  4  and the tapered roller  21 , and at this time, the paper medium in the directions of a long edge and a short edge is at a respective certain angle with respect to the horizontal plane, therefore after the paper medium passes through the horizontal passage interface  131  and before it enters the skew correcting passage between the tapered roller  21  and the tapered cover plate  4 , the inclined turning passage  132  which can achieve this turning function is required. In the horizontal passage interface  131 , the banknote, under the action of the driving banknote picking roller  133  and the guide driven pinch roller  134 , is entered into the inclined turning passage  132 . The inside of the inclined turning passage  132  is a smooth curved surface, and the curved surface is tangent to the curved surface of the inside of the horizontal passage interface  131  at a position where the curved surface is connected to the horizontal passage interface  131 , and the curved surface is tangent to the inner wall curved surface of the tapered cover plate  4  at a position where the curved surface is connected to the tapered roller  21 , thus ensuring a smooth movement of the paper medium. Under the action of the turning driven pinch roller  135 , the paper medium enters the paper medium skew correcting passage between the tapered cover plate  4  and the tapered roller  21 . A driving motor  31  of the driving transmission assembly  3  drives the driving synchronous pulley  33  to rotate, and the synchronous pulley  33  drives the roller synchronous pulley  34 , the driving banknote picking pulley  36 , the driving banknote conveying pulley  37  and the tensioning guide synchronous pulley  35  to rotate by transmission of the synchronous belt. The roller synchronous pulley  34  is mounted on the tapered roller transmission shaft  23  which drives the tapered roller  21  to rotate. The skew of the paper medium during the conveying and moving process is corrected under the action of a resultant force generated by combined action of the centrifugal force and a rotational kinetic friction force of the tapered roller  21 . When moving in the skew correcting passage, the paper medium may be pressed and guided by the auxiliary pressure rollers  162  of the auxiliary pressure roller mechanism  16 , thus preventing the paper medium from separating from the surface of the tapered roller  21  due to being subjected to a centrifugal force when moving in the paper medium skew correcting passage. The pressure acting on the paper medium by the auxiliary pressure roller  162  may be adjusted by the pressing force adjusting spring  165  of the auxiliary pressure roller mechanism  16 . Under the co-action of the centrifugal force and the friction force, the paper medium slides towards a large end of the tapered roller  21 , and when fitting the end face reference plate  222  at the large end, the paper medium stops moving axially due to being blocked by the end face reference plate  222 , thus achieving the skew correction to the paper medium during conveying and moving process. After the skew correction is achieved, the slant driven pinch roller  144  acts on the paper medium to prevent it from skewing again. Since in the subsequent processing, the paper medium is required to be in a horizontal state, the banknote is required to vary from the original skewed state to the horizontal state after skew is corrected and before the paper medium is outputted, therefore, the horizontal turning passage  141  between the tapered passage exit and the outward transfer horizontal passage  142  is required to turn the paper medium from an inclined state to a horizontal state. The inner wall of the horizontal turning passage  141  is a smooth curved surface, and the curved surface is tangent to the inner wall of the tapered cover plate  4  at the position where the curved surface is connected to the tapered cover plate  4 , and the curved surface is tangent to the inner wall of the outward transfer passage  142  at the position where the curved surface is connected to the outward transfer passage  142 , to ensure the smooth movement of the paper medium in the horizontal turning passage  141 . Then the paper medium enters the horizontal turning passage  141  to be varied from being inclined to being horizontal, and enters the outward transfer horizontal passage  142 , and the skew-corrected medium is outputted with the power provided by the driving delivery roller  143 . 
     Accordingly, a paper medium skew correcting method according to the present embodiment includes the following three steps. In step 1, a paper medium to be skew-corrected enters the entrance leading passage  13  of the above paper medium skew correcting device, and enters the paper medium skew correcting passage between the tapered cover plate  4  and the tapered roller  21  via the horizontal passage interface  131  and the inclined turning passage  132 . In step 2, the paper medium slides towards the large end of the tapered roller  21  under the co-action of the centrifugal force and the rotational kinetic friction force of the tapered roller  21 , and when an edge of the paper medium fits the large end surface reference plate  222 , the paper medium stops moving axially due to being blocked by the large end surface reference plate  222 , thus achieving the skew correction to the paper medium during conveying and moving process. In step 3, the paper medium enters the outward transfer horizontal passage  142  via the horizontal turning passage  141 , thus the skew-corrected paper medium is outputted. Preferably, in step 1, the paper medium in the horizontal passage interface  131  is entered into the inclined turning passage  132  under the action of the driving banknote picking roller  133  and the guide driven pinch roller  134 , and then is entered into the paper medium skew correcting passage between the tapered cover plate  4  and the tapered roller  21  under the action of the turning driven pinch roller  135 . In step 3, when the paper medium enters the horizontal turning passage  141  from the skew correcting passage, the slant driven pinch roller  143  acts on the paper medium to prevent the paper medium from being skewed again, and the driving delivery roller  144  provides power to output the skew-corrected paper medium. Preferably, in step 2, the auxiliary pressure roller mechanism  16  acts on the surface of the tapered roller  21 , to apply a pressure on the paper medium passing through the paper medium skew correcting passage and guide the paper medium, to prevent the paper medium from separating from the outer surface of the tapered roller  21  due to the action of the centrifugal force generated when the paper medium moves in the skew correcting passage. 
     The paper medium skew correcting device according to the present application adopts the tapered roller assembly to achieve skew correction of banknotes. The tapered roller and the tapered cover plate in the tapered roller assembly cooperate to form the paper medium skew correcting passage. The power for the banknotes moving in the skew correcting passage is only provided by the driving transmission assembly. Since the skew correcting passage formed by the tapered roller and the tapered cover plate is around the tapered roller, the skew correcting passage does not occupy a large space in the horizontal direction, and the tapered roller has a simple structure and is easy to assemble. Therefore, the paper medium skew correcting device according to the present application effectively simplifies the structure, reduces the manufacturing and assembling costs of the products, and fully utilizes the co-action of the centrifugal force and friction force generated in the movement of the paper medium along with the tapered roller to achieve skew correction and conveying of the paper medium, thereby fundamentally overcoming the technical issue of jam of the valuable paper medium in the device due to a too large skew correcting force. Also, since the structure is simplified, the device can effectively reduce the volume, and facilitates the integration of the device in other apparatuses such as ATMs, and the cash counter. 
     The embodiments described hereinabove are only preferred embodiments of the present application, and should not be interpreted as limitation to the protection scope of the present application, and the protection scope of the present application should be defined by the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.