Patent Publication Number: US-9404528-B2

Title: Locking assembly and supporting device therewith

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a locking assembly and a supporting device therewith, and more specifically, to a locking assembly with easy operation and capable of preventing a frame from being folded accidentally and a supporting device therewith. 
     2. Description of the Prior Art 
     It is a common way for parents to use an infant seat to carry a baby. For now, there are various infant seats in the market, such as an infant carrier, an infant car seat, and so on. The infant seats are practical for being carried or being installed inside a car. For example, the baby basket solves a problem that the parents must hold the baby by hands and cannot put the baby down when the parents go outside and feel tired. The infant car seat solves a problem that the baby is too small to be fastened by vehicle belt or other fixing band, and the infant car seat provides the parents with great convenience when the parents go outside. 
     As the infant seats are widely used gradually, people request more convenience in operation of the infant seat. The infant seats described above have to be disposed on the stroller or a specific supporting frame. However, for cooperating with various infant seats in the market, the connection between the infant seat with the stroller or the supporting frame is usually designed to be a detachable structure. In addition, in order to facilitate the parents to carry or store the stroller or the supporting frame, the stroller or the supporting frame is usually designed to be able to be folded. Accompanying with multi-functions of the infant seat, a safety requirement is also an important issue of the infant seat. However, the foldable stroller or the supporting frame may be folded accidentally as the infant seat is coupled thereon. Therefore, it is necessary to provide a structure which is operated easily and can prevent the stroller or the supporting frame from being folded accidentally, to solve the above problems. 
     SUMMARY OF THE INVENTION 
     A purpose of the present invention is to provide a locking assembly with a safety lock mechanism, so as to facilitate a supporting device to be operated easily, and to prevent the supporting device from being folded accidentally, to enhance operating safety. 
     In order to achieve the above purpose, the present invention provides a locking assembly including a joint device and a safety lock mechanism. The joint device includes a first joint component, a second joint component and a button assembly. The second joint component is pivoted to the first joint component. The button assembly is slidably disposed between the first joint component and the second joint component, and the button assembly is for locking a pivotal movement between the first joint component and the second joint component. The safety lock mechanism movably passes through the second joint component to selectively engage with or separated from the button assembly, so as to lock or release movement of the button assembly selectively. 
     Preferably, an installing slot is formed on the second joint component, and the safety lock mechanism is movably disposed on the installing slot. 
     Preferably, a hole is formed on the second joint component, and the safety lock mechanism movably passes through the hole. 
     Preferably, a moving direction of the safety lock mechanism is intersected with a pivotal plane formed by the first joint component and the second joint component. 
     Preferably, the moving direction of the safety lock mechanism is perpendicular to the pivotal plane. 
     Preferably, a moving direction of the safety lock mechanism is intersected with a sliding plane formed by the button assembly. 
     Preferably, the moving direction of the safety lock mechanism is perpendicular to the sliding plane. 
     Preferably, the safety lock mechanism includes a locking block movably passing through the second joint component. 
     Preferably, the safety lock mechanism further includes a resilient component disposed between the locking block and the second joint component. 
     Preferably, the locking block includes a base portion, a contacting portion, a pushing portion and an engaging portion. The contacting portion is formed on a side of the base portion, and the resilient component is disposed between the contacting portion and the second joint component. The pushing portion is formed on the other side of the base portion, and the pushing portion is for movably passing through the second joint component. The engaging portion is formed on the pushing portion, the engaging portion being for detachably engaging with the button assembly. 
     Preferably, a portion of the locking block exposed outside the second joint component comprises an inclined surface or a curved surface. 
     Preferably, a locking slot is formed on the button assembly and for engaging with the locking block. 
     Preferably, the locking block and the locking slot are engaged by a mortise joint. 
     Preferably, a supporting device for supporting an infant seat, comprising a supporting frame, a joint device disposed on one sides of the supporting frame, and a safety lock mechanism. The joint device includes a first joint component, a second joint component pivoted to the first joint component, and a button assembly movable disposed between the first joint component and the second joint component. The safety lock mechanism is movably disposed on the second joint component to selectively engage with the button assembly, so as to prevent button assembly from moving. 
     Preferably, the button assembly includes a sliding block slidably disposed on the first joint component. 
     Preferably, the sliding block comprises a protruding block to engage with the second joint when the supporting device is at an extended state. 
     Preferably, the supporting frame includes two first supporting frames and two second supporting frames, the supporting device includes two joints device, and the two joint devices are disposed between the two first supporting frames and the two second supporting frames respectively. 
     Preferably, a combination includes an infant seat and a support device for detachably coupling with the infant seat. The supporting device includes a supporting frame, a joint device and a safety lock mechanism. The supporting frame is movable between an extended state and a folded state. The joint device is disposed on the supporting frame comprising a button assembly for locking the joint device so as to retain the support frame being at the extended state. The safety lock mechanism is movably disposed on joint device, wherein the joint device includes a coupling portion to allow the infant seat to engage thereon, when the infant seat is coupling with the joint device, the infant seat presses the safety lock mechanism to engage with the assembly. 
     Preferably, a combination includes an infant seat and a support device for detachably coupling with the infant seat. The supporting device includes a supporting frame, a joint device and a safety lock mechanism. The supporting frame is movable between an extended state and a folded state. The joint device is disposed on the supporting frame and includes a first joint component, a second joint component pivoted to the first joint component and a button assembly disposed between the first joint component and the second joint component. The button assembly is movable between a locking position when the first joint component and the second joint component is locked and a released position when the first joint component and the second joint component are free to move relative to each other. The safety lock mechanism is movably disposed the second joint and includes a locking block retractably disposed on the second joint component, wherein when button assembly is at the released position, the first joint component and the second joint component are pivoted relative to each other, and the button assembly is abutted against the locking block so that the locking block cannot retract into the second joint component, so as to prevent the infant seat from coupling with the supporting device. 
     In contrast to the prior art, the safety lock mechanism of the present invention can movably passes through the second joint component to engage with or detached from the button assembly, so as to lock or release the button assembly. Therefore, only when the supporting device is unfolded completely, the infant seat is able to install on the joint device, so as to prevent the supporting device from being folded accidentally in a procedure of installing the infant seat on the supporting device. In addition, as the supporting device is not unfolded completely, the infant seat is not able to install on the joint device, so as to increase the operating safety and to prevent an error operation of installation. After detaching the infant seat from the supporting device, the locking block is separated from the button assembly, so that the button assembly is released and the supporting device is able to be folded, so as to ensure the safety of operating the infant seat. 
     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 an assembly diagram of a supporting device and an infant seat according to an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of the supporting device according to the embodiment of the present invention. 
         FIG. 3  is a diagram of a joint device on a left side of a supporting frame according to the embodiment of the present invention. 
         FIG. 4  is a diagram of a joint device on a right side of the supporting frame according to the embodiment of the present invention. 
         FIG. 5  is a diagram illustrating that a safety lock mechanism is pushed inside the joint device according to the embodiment of the present invention. 
         FIG. 6  to  FIG. 8  are partial diagrams of the safety lock mechanism and the joint device in different views according to the embodiment of the present invention. 
         FIG. 9  is an exploded diagram of the second joint component and the safety lock mechanism according to the embodiment of the present invention. 
         FIG. 10  is an exploded diagram of the safety lock mechanism according to the embodiment of the present invention. 
         FIG. 11  is an assembly diagram of the safety lock mechanism and a button assembly according to the embodiment of the present invention. 
         FIG. 12  is a sectional view illustrating that safety lock mechanism is disengaged from and abuts against the button assembly as the supporting device is in an extended state and the joint device is in a released state according to the embodiment of the present invention. 
         FIG. 13  is a sectional view illustrating that safety lock mechanism is engaged with the button assembly as the supporting device is in the extended state and the joint device is in a locking state according to the embodiment of the present invention. 
         FIG. 14  is a sectional view illustrating that safety lock mechanism is disengaged from and abuts against the button assembly as the supporting device is in a partially extended state and the joint device is in the released state according to the embodiment of the present invention. 
         FIG. 15  is a sectional view illustrating that safety lock mechanism is disengaged from and abuts against the button assembly as the supporting device is a folded state and the joint device is in the released state according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present invention is described with figures, and similar labels represent similar components. 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 maybe 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. 
     Please refer to  FIG. 1  and  FIG. 2 .  FIG. 1  is an assembly diagram of a supporting device  1  and an infant seat  2  according to an embodiment of the present invention.  FIG. 2  is a schematic diagram of the supporting device  1  according to the embodiment of the present invention. The present invention provides a combination  100  including the infant seat  2  and the supporting device  1  for detachably coupling with and supporting the infant seat  2 . The infant seat  2  can be an infant carrier, an infant car seat or other infant seats. 
     As shown in  FIG. 1  and  FIG. 2 , the supporting device  1  includes a supporting frame  10  and two locking assemblies  5 . The supporting frame  10  includes two first supporting frames  11  and two second supporting frames  12 . The supporting frame  10  of the supporting device  1  is movable between an extended state and a folded state. Each locking assembly  5  includes a joint device  20  and a safety lock mechanism  30  connected to the joint device  20 . Two joint devices  20  are disposed on two sides of the supporting frame  10 , and the infant seat  2  can be detachably engaged with the two joint devices  20 . Two safety lock mechanisms  30  are disposed on the two joint devices  20  symmetrically. In this embodiment, each joint device  20  is connected to the corresponding first supporting frame  11  and the corresponding second supporting frame  12 . The two first supporting frames  11  and the two second supporting frames  12  can move forward and backward respectively, so that the supporting device  1  can be extended to support the infant seat  2 . In addition, the two first supporting frames  11  can pivot relative to the two second supporting frames  12  via the joint device  20 , so as to fold the supporting device  1 . 
     The two joint devices  20  and the two safety lock mechanisms  30  are disposed on the supporting device  1  symmetrically. Hence, the joint device  20  and the safety lock mechanism  30  on one side of the supporting frame  10  are described as follows in detail. 
     Please refer to  FIG. 3  to  FIG. 5 .  FIG. 3  is a diagram of the joint device  20  on a left side of the supporting frame  10  according to the embodiment of the present invention.  FIG. 4  is a diagram of the joint device  20  on a right side of the supporting frame  10  according to the embodiment of the present invention.  FIG. 5  is a diagram illustrating that the safety lock mechanism  30  is pushed inside the joint device  20  according to the embodiment of the present invention. The joint device  20  includes a first joint component  21 , a second joint component  22  and a button assembly  23 . The first joint component  21  and the second joint component  22  are pivoted on each other. The first joint component  21  and the second joint component  22  are connected to the first supporting frame  11  and the second supporting frame  12  respectively. In this embodiment, an outer side of the second joint component  22  included a coupling portion  35  to allow the infant seat  2  to engage thereon. The button assembly  23  is disposed between the first joint component  21  and the second joint component  22 , and the button assembly  23  is for locking or releasing a pivotal movement of the first joint component  21  and the second joint component  22 . That is, the button assembly  23  is for locking or releasing the joint device  20 . The safety lock mechanism  30  is disposed on the second joint component  22  and movably passes through the corresponding second joint component  22  to detachably engage with the corresponding button assembly  23 , so as to lock the corresponding button assembly  23 . That is, the safety lock mechanism  30  can be selectively engaged with or detached from the button assembly  23 . As the safety lock mechanism  30  is not engaged with the button assembly  23 , a portion of the safety lock mechanism  30  protrudes outside the second joint component  22 . 
     Please refer to  FIG. 3  to  FIG. 9 .  FIG. 6  to  FIG. 8  are partial diagrams of the safety lock mechanism  30  and the joint device  20  in different views according to the embodiment of the present invention.  FIG. 9  is an exploded diagram of the second joint component  22  and the safety lock mechanism  30  according to the embodiment of the present invention. Refer to  FIG. 7 , the first joint component  21  includes a first wall  211 , a first base  212 , a guiding way  213 , a shaft  214  and a block  215 . The first wall  211  is connected to a peripheral of the first base  212  upright. The guiding way  213  is formed on an inner surface of the first base  212 , and the shaft  214  protrudes from the first base  212  and positioned and passes through the guiding way  213 . An opening is formed on a lower end of the first base  212  where corresponds to the guiding way  213  and is space communicated with the guiding way  213 . The block  215  is formed on an upper end of the first base  212  where corresponds to the guiding way  213 . The shaft  214  is pivotally connected the second joint component  22 , and the button assembly  23  is slidably installed on the guiding way  213  so as to movably connect to the first base  212  of the first joint component  21 . 
     Correspondingly, Refer to  FIG. 6, 8 and 9 , the second joint component  22  includes a second wall  221 , a second base  222  and a column  223 . The second wall  221  is connected to a peripheral of the second base  222  upright, and the second wall  221  is coupled with the first wall  211 . The button assembly  23  is movably connected to the first base  212  and is selectively engaged with or detached from the column  223 . Specifically, the column  223  is disposed on an inner surface of the second base  222 , and a pivoting hole  223   a  corresponding to the shaft  214  is formed on the column  223 . The shaft  214  is pivoted to the pivoting hole  223   a , so that the first joint component  21  can be pivoted on the second joint component  22 . In addition, two fixing portions  227  are disposed on the inner surface of the second base  222  separately, and an installing slot  228  is formed on the second joint component  22  and between the two fixing portions  227 . The safety lock mechanism  30  is movably installed inside the installing slot  228 , and the portion of the safety lock mechanism  30  protrudes outside the second joint component  22 . 
     As shown in  FIG. 6  to  FIG. 8 , the button assembly  23  includes a sliding block  231  and a recovering component  237 . A side wall  231   a  is formed on a side of the sliding block  231 , and the side wall  231   a  is a ring-shaped structure. A sliding slot  232  with a long shape is formed on the sliding block  231 . A pressing portion  233  is extended from a low end of the sliding block  231 . A first protruding block  234  is extended from inner side of an upper end of the side wall  231   a  downwardly, and a second protruding block  235  is extended from inner side of a lower end of the side wall  231   a  downwardly. The sliding block  231  is slidably disposed on the guiding way  213  of the first joint component  21 , and the shaft  214  passes through the sliding slot  232 . The recovering component  237  is disposed inside the sliding slot  232  and two ends of the recovering component  237  abut against the shaft  214  and the pressing portion  233 . The pressing portion  233  passes through the opening to expose outside the first joint component  21 . The first protruding block  234  is detachably engaged with the column  223 . The sliding block  231  is slidably along the guiding way  213  and is not interfered by other objects, so that the sliding block  231  is protected and can move stably. User is allowed to press the pressing portion from outside of the first joint component  21  and the second joint component  22 , so as to drive the sliding block  231  to move, and the first protruding block  234  is disengaged from the column  223 . The pressing portion  233  is designed to be operated more easily. 
     An engaging slot  224  corresponding to the first protruding block  234  of the button assembly  23  is formed on a side wall of the column  223 . A concave  225  is formed on an inner wall of the second wall  221 , and the engaging slot  224  and the concave  225  are aligned on a straight line. The concave  225  corresponds to the second protruding block  235  of the button assembly  23 . Therefore, the first protruding block  234  is selectively engaged with or detached from the engaging slot  224 , and the second protruding block  235  is selectively engaged with or detached from the concave  225 . As the first protruding block  234  is engaged with the engaging slot  224  and the second protruding block  235  is engaged with the concave  225 , the two first supporting frames  11  and the two second supporting frames  12  are away from each other, so that the supporting device  1  is in an extended state. 
     Furthermore, a limiting slot  226  is formed on the second wall  221 , and the block  215  on an inner surface of the first wall  211  is slidably coupled to the limiting slot  226 . The angle of pivotal movement of the first joint component  21  and the second joint component  22  is constrained by the cooperation between the block  215  and the limiting slot  226 . For example, as the first joint component  21  pivots relative to the second joint component  22  and the two first supporting frames  11  and the two second supporting frames  12  move close to each other or move away from each other, the cooperation between the block  215  and the limiting slot  226  can prevent the two first supporting frames  11  and the two second supporting frames  12  from being too close to each other or too far away from each other. 
     Please refer to  FIG. 6  to  FIG. 11 .  FIG. 10  is an exploded diagram of the safety lock mechanism  30  according to the embodiment of the present invention.  FIG. 11  is an assembly diagram of the safety lock mechanism  30  and the button assembly  23  according to the embodiment of the present invention. The second joint component  22  includes a strip block  31 , and the safety lock mechanism  30  includes a resilient component  32  and a locking block  33 . The locking block  33  movably passes through a hole of the second joint component  22 . That is, the locking block  33  is movably disposed on the installing slot  228 , and a portion of the locking block  33  of the safety lock mechanism  30  protrudes outside the second joint component  22 . The locking block  33  is detachably engaged with the button assembly  23  . The strip block  31  is disposed on the inner surface of the second joint component  22  and fixed on the two fixing portions  227 . Two ends of resilient component  32  are abutted against the locking block  33  and the strip block  31  of the second joint component  22 . Therefore, the locking block  33  is biased by the resilient component  32  to protrude outside the second joint component  22 . A moving direction of the locking block  33  of the safety lock mechanism  30  is intersected with a pivotal plane formed by the first joint component  21  and the second joint component  22 . Preferably, the moving direction of the locking block  33  of the safety lock mechanism  30  is perpendicular to the pivotal plane. 
     As shown in  FIG. 8  and  FIG. 9 , the two fixing portions  227  are disposed on the inner surface of the second base  222 . Specifically, the two fixing portions  227  are disposed on a side of the straight line where the engaging slot  224  and the concave  225  are located on. The installing slot  228  is formed between the two fixing portions  227 , and the hole communicated with the installing slot  228  is formed on the second base  222  of the second joint component  22 . The hole penetrates through the second joint component  22 , and the safety lock mechanism  30  movably passes through the hole. The locking block  33  is movably disposed on the installing slot  228 , and an end of the locking block  33  passes through the hole and protrudes outside the second joint component  22 . The end of the locking block  33  is positioned on area of the coupling portion  35  of the second joint component  22  after passing through thereon. An end of the resilient component  32  contacts against the other end of the locking block  33 , and the other end of the resilient component  32  contacts against the strip block  31 . Two ends of the strip block  31  are fixed on the two fixing portions  227  respectively. 
     As shown in  FIG. 8  to  FIG. 11 , the locking block  33  includes a base portion  331 , a contacting portion  332 , a pushing portion  333  and an engaging portion  334 . The contacting portion  332  is formed on a side of the base portion  331 , and a protrusion  332   a  is formed on the contacting portion  332 . The pushing portion  333  is formed on the other side of the base portion  331 , and the pushing portion  333  includes a pushing surface  333   a  which is an inclined structure in this embodiment. The pushing surface  333   a  is not limited to the inclined structure and can be other structures, such as a curved structure on the other embodiment. The engaging portion  334  is extended from the pushing portion  333 . As the locking block  33  is installed on the installing slot  228  of the second joint component  22 , the pushing portion  333  passes through the hole and protrudes outside the second joint component  22 . The pushing surface  333   a  inclines from top to bottom. The end of the resilient component  32  sheathes the protrusion  332   a , and the resilient component  32  is disposed between the contacting portion  332  and the strip block  31 . The engaging portion  334  is detachably engaged with the button assembly  23 . Correspondingly, a locking slot  236  is formed on a side of the sliding block  231  of the button assembly  23 , and the locking slot  236  is for engaging with the locking block  33 . A shape of the locking slot  236  corresponds to a shape of the engaging portion  334 . In this embodiment, the engaging portion  334  of the locking block  33  and the locking slot  236  are engaged by a mortise joint. Preferably, the mortise joint can be a dovetail joint. 
     As the supporting device  1  shown in  FIG. 2  is extended completely, the button assembly  23  locks the pivotal movement of the first joint component  21  and the second joint component  22 . That is, the button assembly  23  is at a locking position when the first joint component  21  and the second joint component  22  are locked. The engaging portion  334  is aligned to the locking slot  236 . Then, as shown in  FIG. 1 , as the infant seat  2  is to be installed on the supporting device  1 , the infant seat  2  contacts and pushes the pushing surface  333   a  to install on the two joint devices  20 . Therefore, the locking block  33  is pushed to retracted into the second joint component  22 , so that the engaging portion  334  is engaged into the locking slot  236 , preventing the sliding block  231 , from moving so as to prevent the supporting device  1  from being folded accidentally in a procedure of installing the infant seat  2  on the supporting device  1 . As the infant seat  2  is detached from the supporting device  1 , the resilient component  32  returns the locking block  33 , so that the engaging portion  334  is separated from the locking slot  236 , and the sliding block  231  is released. Therefore, a moving direction of the safety lock mechanism  30  is intersected with a sliding plane formed by the button assembly  23 . That is, a sliding direction of the sliding block  231  is intersected with a sliding direction of the locking block  33 . Preferably, the moving direction of the safety lock mechanism  30  is perpendicular to the sliding plane. That is, the sliding direction of the sliding block  231  is perpendicular to the sliding direction of the locking block  33 . 
     As the supporting device  1  is in the partially extended state the locking slot  236  is not aligned to the engaging portion  334 . Therefore as the infant seat  2  is desired to couple with the with the supporting device  1  and pushes the pushing surface  333   a , the sliding block  231  is abutted against the engaging portion  334  to prevent the locking block  33  from retracting into the second joint component  22 . Hence, the infant seat  2  cannot be coupled with the supporting device  1  in this situation, so as to ensure the operating safety of the infant seat  2 . 
     Operational principle and procedure of the supporting device  1  are described with  FIG. 1  to  FIG. 15 .  FIG. 12  is a sectional view illustrating that safety lock mechanism  30  is disengaged from and abuts against the button assembly  23  as the supporting device  1  is in the extended state and the joint device  20  is in a released state according to the embodiment of the present invention.  FIG. 13  is a sectional view illustrating that safety lock mechanism  30  is engaged with the button assembly  23  as the supporting device  1  is in the extended state and the joint device  20  is in a locking state according to the embodiment of the present invention.  FIG. 14  is a sectional view illustrating that safety lock mechanism  30  is disengaged from and abuts against the button assembly  23  as the supporting device  1  is in a partially extended state and the joint device  20  is in the released state according to the embodiment of the present invention.  FIG. 15  is a sectional view illustrating that safety lock mechanism  30  is disengaged from and abuts against the button assembly  23  as the supporting device  1  is a folded state and the joint device  20  is in the released state according to the embodiment of the present invention. 
     As the supporting frame  10  is in the folded state or is not extended completely, the first protruding block  234  contacts against the side wall of the column  223 , so that the button assembly  23  cannot return to the locking position. That is, the button assembly  23  is at a released position when the first joint component  21  and the second joint component  22  are free to move relative to each other. As shown in  FIG. 14  and  FIG. 15 , the button assembly  23  releases the pivotal movement of the first joint device  21  and the second joint device  22 . As the infant seat  2  is desired to be installed on the supporting device  1 , the two first supporting components  11  and the two second supporting components  12  move away from each other, so that the supporting device  1  is moved toward the extended state. As the supporting device  1  is extended completely, as shown in  FIG. 12 , the first protruding block  234  of the button assembly  23  is aligned to the engaging slot  224  of the column  223 , and the second protruding block  235  is aligned to the concave  225 . At this time, the sliding block  231  is returned to the locking position by the recovering component  237 , so that the first protruding block  234  of the button assembly  23  is engaged inside the engaging slot  224  of the column  223 , and the second protruding block  235  is engaged inside the concave  225 , so as to lock the joint device  20  by the button assembly  23 , as shown in  FIG. 13 . The locking slot  236  of the sliding block  231  is aligned to the engaging portion  334  when the sliding block  231  is at the locking position 
     As the infant seat  2  is installed on the supporting device  1 , the infant seat  2  slides along and is engaged with the coupling portion  35  of the second joint component  22 , therefore the infant seat  2  contacts and presses the pushing surface  333   a  of the locking block  33 , so that the locking block  33  slides along the hole and retracts into the second joint component  22 . Therefore, the engaging portion  334  of the locking block  33  is engaged into the locking slot  236  of the sliding block  231 , so that the sliding block  231  cannot slide along the guiding way  213  to release the pivotal movement of the first joint device  21  and the second joint device  22 , so as to prevent the supporting frame  10  from being folded accidentally when the infant seat  2  is coupled thereon. That is, only when the supporting device  1  is extended completely, the locking slot  236  of the sliding block  231  is aligned to the engaging portion  334 , and the locking block  33  is able to retract into the second joint component  22 , so that the infant seat  2  is able to engage with the supporting frame  10 . On the contrary, if the supporting frame  10  is not extended completely, the locking slot  236  is not aligned to the engaging portion  334 , so that the sliding block  231  abuts against the engaging portion  334  of the locking block  33 . Therefore, the locking block  33  cannot retract into the second joint component  22 , so as to prevent the infant seat  2  from engaging with the supporting frame  10 . The first joint component  21  and the second joint component  22  of the joint device  20  are not locked by the button assembly  23  and can pivot relative to each other freely as the supporting device  1  is not unfolded completely. It is very dangerous to install the infant seat  2  on the supporting device  1  when the supporting device  1  is not extended completely, and the present invention provides the safety lock mechanism  30  to prevent this danger. 
     As the infant seat  2  is detached from the supporting device  1 , the locking block  33  is returned by the resilient component  32  to protrude outside the second joint component  22  again, so that the engaging portion  334  is separated from the locking slot  236 . As a result, the pressing portion  233  can be operated to press so that the sliding block  231  is able to slide along the guiding way  213 , and then the first protruding block  234  and the second protruding block  235  are separated from the engaging slot  224  and the concave  225  respectively, so as to release the button assembly  23  to fold the supporting device  1  pivotally. 
     The engaging portion  334  of the locking block  33  of the safety lock mechanism  30  is detachably engaged with the button assembly  23 . As the supporting device  1  is extended completely, the infant seat  2  pushes the locking block  33 , so as to engage the engaging portion  334  with the button assembly  23  correspondingly. Therefore, the button assembly  23  cannot be released, so as to prevent the supporting device  1  from being folded accidentally in the procedure of installing the infant seat  2  on the supporting device  1 . After detaching the infant seat  2  from the supporting device  1 , the engaging portion  334  is separated from the button assembly  23 , so that the button assembly  23  is released and can be operated to fold the supporting device  1 . As the supporting device  1  is not extended completely, the locking block  33  contacts against the button assembly  23  and cannot move into the second joint component  22 , so as to prevent the infant seat  2  from engaging with the supporting device  1 , so as to ensure the operating safety of the infant seat  2 . An operation of folding the supporting device  1  with the safety lock mechanism  30  of the present invention is simple. 
     In contrast to the prior art, the safety lock mechanism of the present invention can movably passes through the second joint component to engage with or detached from the button assembly, so as to lock or release the button assembly. Therefore, only when the supporting device is unfolded completely, the infant seat is able to install on the joint device, so as to prevent the supporting device from being folded accidentally in a procedure of installing the infant seat on the supporting device. In addition, as the supporting device is not unfolded completely, the infant seat is not able to install on the joint device, so as to increase the operating safety and to prevent an error operation of installation. After detaching the infant seat from the supporting device, the locking block is separated from the button assembly, so that the button assembly is released and the supporting device is able to be folded, so as to ensure the safety of operating the infant seat. 
     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.