Patent Publication Number: US-2022212576-A1

Title: Backrest locking mechanism and child safety seat therewith

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 17/028,992, filed on Sep. 22, 2020. The content of the application is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a child product, and more specifically, to a backrest locking mechanism which has simple structure and capability of easy and convenient attachment and detachment of a backrest and a base, and a child safety seat therewith. 
     2. Description of the Prior Art 
     A child safety seat is an apparatus which can be installed on a vehicle for securing a child. When an emergency brake or an accident happens, a shell of the child safety seat can absorb a shock to reduce an impact force acting on the child, and a restraining device of the child safety seat can restrain a movement of the child&#39;s body, so as to prevent injury of the child for ensuring the child&#39;s safety. 
     The child safety seat usually includes a base, a backrest connected to the base, and a headrest connected to the backrest. For easy package, transportation and storage, the backrest can be configured to be detachable from the base, and the child safety seat further includes a locking mechanism for allowing or restraining detachment of the backrest from the base. However, structure of the conventional locking mechanism is complicated, and operation of the conventional locking mechanism is not user-friendly. Therefore, improvement of the conventional locking mechanism is urgently desired. 
     SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide a backrest locking mechanism which has simple structure and capability of easy and convenient attachment and detachment of a backrest and a base, and a child safety seat therewith for solving the aforementioned problems. 
     In order to achieve the aforementioned objective, the present invention discloses a backrest locking mechanism adapted for a backrest and a base of a child safety seat. The backrest is detachably connected to the base, and the backrest locking mechanism includes a locking pin, a locking component and an operating component. The locking pin is disposed on the base. The locking component is disposed on the backrest. A locking hole structure is formed on the locking component. The locking pin is configured to detachably engage with the locking hole structure. The operating component is movably disposed on the backrest or the base. The operating component drives the locking pin and the locking hole structure to engage with or disengage from each other when the operating component is operated. 
     According to an embodiment of the present invention, one of the locking component or the locking pin is retractable and extendable. 
     According to an embodiment of the present invention, the operating component is connected to one of the locking component or the locking pin and configured to drive the one of the locking component or the locking pin to retract or extend. 
     According to an embodiment of the present invention, the operating component is a pressing component, a sliding component or a rotating component. 
     According to an embodiment of the present invention, the backrest locking mechanism further includes a recovering component connected to the operating component. The recovering component is resiliently deformed when the operating component is operated, and the resiliently deformed recovering component drives the operating component to recover. 
     According to an embodiment of the present invention, the operating component is slidable between a first position and a second position. The locking pin and the locking hole structure engage with each other when the operating component is located at the first position. The operating component drives the locking pin and the locking hole structure to disengage from each other when the operating component slides from the first position to the second position, and the recovering component biases the operating component to slide from the second position to the first position. 
     According to an embodiment of the present invention, the locking component is fixedly connected to the operating component and slidable together with the operating component. The locking component includes a locking plate extending along a direction perpendicular to a longitudinal direction of the locking pin, and the locking hole structure is formed on the locking plate. 
     According to an embodiment of the present invention, the locking component further includes a connecting arm fixedly connected to the locking plate and the operating component for being driven by the operating component, and an included angle is formed between the connecting arm and the locking plate. 
     According to an embodiment of the present invention, the locking pin is fixedly connected to the operating component and slidable together with the operating component. The locking component includes a locking plate extending along a direction perpendicular to a longitudinal direction of the locking pin, and the locking hole structure is formed on the locking plate. 
     According to an embodiment of the present invention, a sliding direction of the operating component is parallel to a longitudinal direction of the locking pin, and the recovering component and the locking pin are located at two opposite sides of the operating component. 
     According to an embodiment of the present invention, an operating recess is formed on an end of the operating component exposed out of the backrest or the base. 
     According to an embodiment of the present invention, a ball head protrudes from an end of the locking pin adjacent to the locking component, and an outer diameter of the ball head is greater than an outer diameter of the locking pin. 
     In order to achieve the aforementioned objective, the present invention further discloses a child safety seat. The child safety seat includes a base, a backrest and a backrest locking mechanism. The backrest is detachably connected to the base. The backrest locking mechanism includes at least one locking pin, at least one locking component and at least one operating component. The at least one locking pin is disposed on the base. The at least one locking component is disposed on the backrest. A locking hole structure is formed on the at least one locking component. The at least one locking pin is configured to detachably engage with the locking hole structure. The at least one operating component is movably disposed on the backrest or the base. The at least one operating component drives the at least one locking pin and the locking hole structure to engage with or disengage from each other when the at least one operating component is operated. 
     According to an embodiment of the present invention, at least one mounting arm protrudes from a lower end of the backrest. At least one guiding slot is formed on the base. The at least one mounting arm is at least partially accommodated inside the at least one guiding slot and slidable relative to the at least one guiding slot. The at least one locking component is disposed on the at least one mounting arm. The at least one locking pin is partially located inside the at least one guiding slot, and the at least one locking pin and the locking hole structure engages with each other when the at least one mounting arm is at least partially accommodated inside the at least one guiding slot. 
     According to an embodiment of the present invention, the at least one locking component includes a connecting arm and a locking plate connected to the connecting arm. An included angle is formed between the connecting arm and the locking plate. The connecting arm is slidably disposed on the at least one mounting arm. The locking plate is exposed from a lateral side of the at least one mounting arm. The locking hole structure is formed on the locking plate, and the at least one locking pin is fixedly disposed on the base and protrudes from a side of the base for engaging with the locking hole structure. 
     According to an embodiment of the present invention, at least one sliding hole is formed on the at least one mounting arm, the at least one operating component is at least partially accommodated inside the at least one sliding hole and slidable relative to the at least one sliding hole, and the at least one operating component is connected to the connecting arm. 
     According to an embodiment of the present invention, the backrest locking mechanism further includes at least one recovering component disposed on the at least one mounting arm and abutting against the at least one operating component, and the at least one recovering component is configured to bias the at least one operating component to drive the at least one locking component to slide toward the at least one locking pin. 
     According to an embodiment of the present invention, the at least one locking component is fixedly disposed on the at least one mounting arm. The at least one locking pin is slidably disposed on the base and protrudes from a side of the base for engaging with the locking hole structure. At least one sliding hole is formed on the base. The at least one operating component is at least partially accommodated inside the at least one sliding hole and slidable relative to the at least one sliding hole, and the at least one operating component is connected to the at least one locking pin. 
     According to an embodiment of the present invention, the backrest locking mechanism further includes at least one recovering component disposed on the base and abutting against the at least one operating component, and the at least one recovering component is configured to bias the at least one operating component to drive the at least one locking pin to slide toward the at least one locking component. 
     According to an embodiment of the present invention, a sliding direction of the at least one mounting arm is different from an engaging direction of the at least one locking pin and the locking hole structure. 
     In summary, in the present invention, the locking pin and the locking component of the backrest locking mechanism are respectively disposed on the base and the backrest, and the locking hole structure is formed on the locking component and for engaging with the locking pin. Furthermore, the operating component movably disposed on the backrest or the base drives the locking pin and the locking component to engage with or disengage from each other when the operating component is operated. The present invention not only has simple structure and capability of allowing easy and convenient attachment and detachment of the backrest and the base but also makes the attachment of the backrest and the base more reliable. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a child safety seat according to an embodiment of the present invention. 
         FIG. 2  to  FIG. 4  are diagrams of different portions of the child safety seat according to the embodiment of the present invention. 
         FIG. 5  is a sectional diagram of the child safety seat along an A-A line shown in  FIG. 1  according to the embodiment of the present invention. 
         FIG. 6  is a diagram of a B portion of the child safety seat according to the embodiment of the present invention. 
         FIG. 7  to  FIG. 10  are diagrams of partial structure of a child safety seat according to different embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top”, “bottom”, “front”, “back”, etc., is used with reference to the orientation of the Figure(s) being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. Also, the term “connect” is intended to mean either an indirect or direct electrical/mechanical connection. Thus, if a first device is connected to a second device, that connection may be through a direct electrical/mechanical connection, or through an indirect electrical/mechanical connection via other devices and connections. 
     The present invention provide a backrest locking mechanism adapted for a base of a child safety seat and a backrest of the child safety seat detachably connected to the base. The backrest locking mechanism includes a locking pin, a locking component and an operating component. The locking pin and the locking component are respectively disposed on one and another one of the backrest and the base. A locking hole structure is formed the locking component and for engaging with the locking pin. The operating is movably disposed on the backrest or the base. The operating component can drive the locking pin and the locking hole structure to engage with or disengage from each other when the operating component is operated. Such configuration not only can make attachment of the backrest and the base more reliable and compact but also makes operation of attachment and detachment of the backrest and the base easier and more convenient. In order to illustrate technical specifications and structural features as well as achieved purposes and effects of the present invention, relevant embodiments and figures are described as follows. 
     Please refer to  FIG. 1  to  FIG. 4 .  FIG. 1  is a schematic diagram of a child safety seat  100  according to an embodiment of the present invention.  FIG. 2  to  FIG. 4  are diagrams of different portions of the child safety seat  100  according to the embodiment of the present invention. As shown in  FIG. 1  to  FIG. 4 , the child safety seat  100  includes a base  110 , a backrest  120  and a backrest locking mechanism  130 . The backrest  120  is detachably connected to the base  110  by the backrest locking mechanism  130 . The backrest locking mechanism  130  can make the operation of the attachment and detachment of the backrest and the base easier and more convenient. 
     As shown in  FIG. 2  and  FIG. 3 , two mounting arms  121  protrude from two sides of a lower end of the backrest  120  and are parallel to each other. Two guiding slots  111  are formed on an upper surface of the base  110  and at locations corresponding to the two mounting arms  121 . The backrest locking mechanism  130  is partially disposed between each mounting arm  121  and a lateral wall of the corresponding guiding slot  111 . The backrest locking mechanism  130  can lock the two mounting arms  121  onto the base  110  for restraining the backrest  120  from being detached from the base  110  when the two mounting arms  121  slide into the two guiding slots  111  respectively. When the backrest locking mechanism  130  is in a releasing state, the backrest  120  is allowed to be detached from the base  110 . 
     Please refer to  FIG. 4  to  FIG. 6 .  FIG. 5  is a sectional diagram of the child safety seat  100  along an A-A line shown in  FIG. 1  according to the embodiment of the present invention.  FIG. 6  is a diagram of a B portion of the child safety seat  100  according to the embodiment of the present invention. As shown in  FIG. 4  to  FIG. 6 , the backrest locking mechanism  130  includes two locking pins  131 , two locking components  132  and two operating components  133 . Each locking pin  131  is disposed on the corresponding mounting arm  121 . Each locking component  132  is disposed on the base  110 , and a locking hole structure  1321  is formed on each locking component  132  and corresponding to the corresponding locking pin  131 . Each locking component  132  is retractable and extendable. Each operating component  133  is movably disposed on the base  110  and connected to the corresponding locking component  132 . When each operating component  133  is forced or operated to move, each operating component  133  can drive the corresponding locking component  132  to drive the corresponding locking pin  131  and the corresponding locking hole structure  1321  to engage with or disengage from each other. 
     Preferably, in this embodiment, each operating component  133  can be a sliding component. Two sliding holes  112  are formed on the upper surface of the base  110 . Each sliding component is slidably disposed inside the corresponding sliding hole  112  and partially exposed out of the base  110  through the corresponding sliding hole  112  for allowing a user to operate easily. Each sliding component is connected to the corresponding locking component  132 . When each sliding component slides, each sliding component drives the corresponding locking component  132  to drive the corresponding locking component  132  and the corresponding locking pin  131  to engage with or disengage from each other. 
     However, the structure of the child safety seat is not limited to this embodiment. For example, in another embodiment, the backrest locking mechanism can include one locking pin at one side of the backrest, one locking component at one side of the base, and one operating component slidably disposed on the base and connected to the locking component, wherein there can be only one sliding hole formed on the base for accommodating the operating component. 
     Furthermore, please refer to  FIG. 7  to  FIG. 10 .  FIG. 7  to  FIG. 10  are diagrams of partial structure of the child safety seat according to different embodiments of the present invention. As shown in  FIG. 7 , in this embodiment, the backrest locking mechanism can include one locking pin  131  at one side of the backrest  120 , one locking component  132  at one side of the base  110 , and one operating component  133  slidably disposed on the backrest  120  and connected to the locking pin  131 . The operating component  133  drives the locking pin  131  to retract or extend to drive the locking pin  131  and the locking hole structure  1321  to engage with or disengage from each other when the operating component  133  is operated. That is, the locking pin  131  of this embodiment is retractable and extendable. 
     As shown in  FIG. 8 , in this embodiment, the backrest locking mechanism can include one locking pin  131  at one side of the base  110 , one locking component  132  at one side of the backrest  120 , and one operating component  133  slidably disposed on the base  110  and connected to the locking pin  131 . The operating component  133  drives the locking pin  131  to retract or extend to drive the locking pin  131  and the locking hole structure  1321  to engage with or disengage from each other when the operating component  133  is operated. 
     As shown in  FIG. 9 , in this embodiment, the backrest locking mechanism can include one locking pin  131  at one side of the base  110 , one locking component  132  at one side of the backrest  120 , and one operating component  133  slidably disposed on the backrest  120  and connected to the locking component  132 . The operating component  133  drives the locking component  132  to retract or extend to drive the locking pin  131  and the locking hole structure to engage with or disengage from each other when the operating component  133  is operated. 
     As shown in  FIG. 10 , in this embodiment, the backrest locking mechanism can include two locking pins  131  at two sides of the backrest  120 , two locking components  132  at two sides of the base  110 , and one operating component  133  slidably disposed on the base  110  and movably connected to the locking components  132 . The operating component  133  drives the two locking components  132  to retract or extend to drive the two locking pins  131  and the two locking hole structures  1321  to engage with or disengage from each other when the operating component  133  is operated. 
     In another embodiment, there can be only one mounting arm protruding from the backrest and one guiding slot formed on the base. The backrest locking mechanism can include at least one locking pin and at least one locking component respectively disposed on one and the other one of the mounting arm and the guiding slot. 
     Furthermore, the configuration of the operating component is not limited to the aforementioned embodiments. For example, in another embodiment, the operating component can be a pressing component, such as a pressing button, and a pressing slot is formed on the backrest or the base and corresponding to the pressing component for allowing the pressing component to be pressed. The pressing component can drive the corresponding locking component or the corresponding locking pin to retract or extend to achieve attachment and detachment of the base and the backrest. 
     In another embodiment, the operating component can be a rotating component. A through hole can be formed on the rotating component for allowing the corresponding locking component or the corresponding locking pin to pass therethrough. A portion of the rotating component is exposed out of the base or the backrest for allowing the user to operate easily. When the rotating component is forced to rotate, the rotating component can drive the corresponding locking component or the corresponding locking pin to retract or extend to achieve attachment and detachment of the base and the backrest. 
     In another embodiment, the operating component can be a rotating component including a rotating locking portion, a rotating engaging portion and rotating releasing portion. The rotating engaging portion is configured to engage with the rotating locking portion. The rotating releasing portion is configured to drive the rotating engaging portion to move. Therefore, after the rotating component is rotated to drive the corresponding locking component and the corresponding locking pin to disengage from each other, the rotating engaging portion can be operated to engage with the rotating locking portion, so that the corresponding locking component or the corresponding locking pin which is connected to rotating component can be positioned at a releasing position for allowing the user to detach the backrest from the base without continuously operating the rotating component. Furthermore, when the rotating releasing portion is operated to drive the rotating engaging portion to disengage from the rotating locking portion, the rotating component can be recovered to drive the corresponding locking pin and the corresponding locking component to engage with each other. 
     Furthermore, as shown in  FIG. 4 , the backrest locking mechanism  130  further includes a recovering component  134  which can cooperate with the two operating components  133 . The recovering component  134  is disposed on the base  110  and connected to the two operating components  133 . When each operating component  133  is operated to drive the corresponding locking component  132  to disengage the corresponding locking hole structure  1321  from the corresponding locking pin  131 , each operated operating component  133  can resiliently deform the recovering component  134 . When each operating component  133  is released, the resiliently deformed recovering component  134  can drive each operating component  133  to recover, so as to drive the corresponding locking component  132  to engage the corresponding locking hole structure  1321  with the corresponding locking pin  131 . 
     Preferably, in this embodiment, the recovering component  134  can be a compression spring. However, the present invention is not limited to this embodiment. For example, in another embodiment, the recovering component can be an extension spring, a torsional spring, a leaf spring or any other resilient component which can bias the operating component to recover. 
     Besides, understandably, the configuration and the number of the recovering component are not limited to this embodiment. It depends on practical demands. For example, in another embodiment, the backrest locking mechanism can include two operating components disposed on the base, and the backrest locking mechanism can further include two recovering components disposed on the base independently and connected to the two operating components respectively, and two ends of each recovering component abut against the corresponding operating component and the base. 
     In another embodiment, when the backrest locking mechanism includes two operating components disposed on the backrest, the backrest locking mechanism can include one recovering component disposed on the backrest and connected to and located between the two operating components. 
     In another embodiment, the backrest locking mechanism can include two operating components disposed on the backrest, the backrest locking mechanism can further include two recovering components disposed on the backrest, and two ends of each recovering component abut against the corresponding operating component and the backrest. 
     In another embodiment, the backrest locking mechanism can include one operating component disposed on the base, the backrest locking mechanism can further include one recovering component disposed on the base and connected to the operating component, and two ends of the recovering component abut against the operating component and the base. 
     In another embodiment, the backrest locking mechanism can include one operating component disposed on the backrest, the backrest locking mechanism can further include one recovering component disposed on the backrest and connected to the operating component, and two ends of the recovering component abut against the operating component and the backrest. 
     Specifically, as shown in  FIG. 4  to  FIG. 6 , in this embodiment, each locking pin  131  is fixedly connected to the corresponding mounting arm  121 . A protruding end of each locking pin  131  protrudes from a lateral wall of the corresponding mounting arm  121 . Each locking component  132  is slidably disposed on the base  110 . An end of each locking component  132  whereon the locking hole structure  1321  is formed, is located inside the corresponding guiding slot  111 . Each operating component  133  is slidably connected to the base  110  and fixedly connected to the corresponding locking component  132 , and a sliding direction of each operating component  133  is parallel to a longitudinal direction of the corresponding locking pin  131 . The recovering component  134  is disposed inside the base  110  and abutted between the two operating components  133 . Each locking pin  131  and the recovering component  134  are located at two opposite sides of the corresponding operating component  133 . Each operating component  133  is slidable between a first position and a second position. When each operating component  133  is located at the first position, the corresponding locking pin  131  and the corresponding locking hole structure  1321  engage with each other. When each operating component  133  slides from the first position to the second position, each operating component  133  drives the corresponding locking component  132  to slide to disengage the corresponding locking hole structure  1321  from the corresponding locking pin  131 . The recovering component  134  can bias the two operating components  133  to slide from the second position to the first position to drive the corresponding locking component  132  to slide toward the corresponding locking pin  131 . 
     As shown in  FIG. 4  to  FIG. 6 , each locking component  132  includes a locking plate  1322  and a connecting arm  1323 . An included angle is formed between each locking plate  1322  and the corresponding connecting arm  1323 . An extending direction of each locking plate  1322  can be substantially perpendicular to the longitudinal direction of the corresponding locking pin  131 . Each locking hole structure  1321  is formed on the corresponding locking plate  1322 . A fixing hole is formed on an end of each connecting arm  1323  away from the corresponding locking plate  1322 . Each connecting arm  1323  is slidably disposed inside the base  110 . Each locking plate  1322  is located inside the corresponding guiding slot  111 , as shown in  FIG. 3 . A bottom portion of each operating component  133  is fixedly connected to a connecting component which is fixed onto the fixing hole. Therefore, when each operating component  132  slides, each operating component  133  can drive the corresponding locking component  132  to slide to drive the corresponding locking hole structure  1321  and the corresponding locking pin  131  to engage with or disengage from each other. 
     Furthermore, the two operating components  133  and the two locking components  132  are slidably disposed between the two mounting arms  121 . Correspondingly, the protruding end of each locking pin  131  protrudes from the lateral wall of the corresponding mounting arm  121  which is adjacent to the corresponding operating component  133 . However, the configurations of the locking component and the locking pin are not limited to this embodiment. 
     Besides, a ball head  1311  protrudes from an end of each locking pin  131  adjacent to the corresponding locking component  132 , i.e., the ball head  1311  protrudes from the protruding end of each locking pin  131 . An outer diameter of each ball head  1311  is greater than an outer diameter of the corresponding locking pin  131  and less than an inner diameter of the corresponding locking hole structure  1321 . Each ball head  1311  can guide the corresponding locking pin  131  to engage with the corresponding locking hole structure  1321  easily during a sliding movement of the corresponding mounting arm  121 . 
     As shown in  FIG. 4  to  FIG. 6 , a positioning protrusion  1331  protrudes from a lateral portion of each operating component  133 . The recovering component  134  can be arranged along a direction substantially parallel to the sliding direction of the operating component  133 , and the two ends of the recovering component  134  sheathe on the positioning protrusions  1331  of the two operating components  133  and abut against the two operating components  133  respectively. When each operating component  133  is forced to slide to the second position, the recovering component  134  is forced to be resiliently deformed. When each operating component  133  is released, the resiliently deformed recovering component  134  can recover to drive each operating component  133  to slide to the first position. 
     As shown in  FIG. 3 ,  FIG. 5  and  FIG. 6 , an operating recess  1332  is formed on an upper end of each operating component  133 . The bottom portion of each operating component  133  is fixedly connected to the corresponding connecting arm  1323 . The operating recesses  1332  on the two operating components  133  are exposed out of the upper surface of the base  110  for allowing the user to insert his/her fingers into the two operating recesses  1332  to operate the two operating components  133 , which makes operation of the operating component  133  easier and more convenient. 
     As shown in  FIG. 5  to  FIG. 6 , in this embodiment, an accommodating hole  113  is formed inside the base  110  and communicated with the two sliding holes  112 . The recovering component  134  is accommodated inside the accommodating hole  113 . The two ends of the recovering component  134  abut against the two operating components  133  respectively. Therefore, the user can insert his/her thumb and forefinger into the operating recesses  1332  of the two operating components  133  to drive the operating components  133  to slide from the first position to the second position and toward a middle portion of the base  110  to pull the two locking components  132  to disengage from the two locking pins  131  for allowing the detachment of the backrest  120  from the base  110 . 
     As shown in  FIG. 1  to  FIG. 6 , operational principle of the backrest locking mechanism  130  of the child safety seat  100  is provided as follows. 
     When it is desired to assemble the backrest  120  onto the base  110 , the two mounting arms  121  of the backrest  120  can be slidably inserted into the two guiding slots  111  on the base  110  forwardly along an arrow direction as shown in  FIG. 1  and  FIG. 2 . Each mounting arm  121  can drive the corresponding locking pin  131  to abut against the corresponding locking plate  1322  and to push the corresponding locking component  132  to slide toward the middle portion of the base  110 , so as to drive the corresponding operating component  133  to slide to the second position to compress the recovering component  134  during the forward sliding movement of each mounting arm  121 . When each mounting arm  121  slides to a position where the corresponding locking pin  131  is aligned with the corresponding locking hole structure  1321 , the resiliently deformed recovering component  134  can drive the corresponding operating component  133  to slide to the first position, so as to drive the corresponding locking component  132  to slide toward the corresponding locking pin  131  to engage the corresponding locking hole structure  1321  with the corresponding locking pin  131  for locking the backrest  120  onto the base  110 . Such configuration makes the attachment of the base  110  and the backrest  120  more reliable. 
     As shown in  FIG. 4  to  FIG. 6 , when it is desired to detach the backrest  120  from the base  110 , the user can insert his/her thumb and forefinger into the operating recesses  1332  on the two operating components  133  to drive the two operating components  133  to slide from the first position to the second position and toward the middle portion of the base  110 . When the two operating components  133  slide from the first position to the second position, each operating component  133  drives the corresponding locking component  132  to slide to disengage the corresponding locking hole structure  1321  from the corresponding locking pin  131  for allowing the detachment of the backrest  120  from the base  110 . During the aforementioned process, the recovering component  134  is compressed to be resiliently deformed. Therefore, when the user releases the two operating components  133 , the resiliently deformed recovering component  134  can recover to drive the two operating components  133  to slide from the second position to the first position to drive the two locking components  132  to recover. 
     Detailed description for other structure of the base  110  and the backrest  120  of the child safety seat  100  is omitted herein for simplicity. 
     In contrast to the prior art, in the present invention, the locking pin and the locking component of the backrest locking mechanism are respectively disposed on the base and the backrest, and the locking hole structure is formed on the locking component and for engaging with the locking pin. Furthermore, the operating component movably disposed on the backrest or the base drives the locking pin and the locking component to engage with or disengage from each other when the operating component is operated. The present invention not only has simple structure and capability of allowing easy and convenient attachment and detachment of the backrest and the base but also makes the attachment of the backrest and the base more reliable. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.