Patent Publication Number: US-2022234640-A1

Title: Fixing device and passenger device as well as carrying device using the same

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to a passenger device and a carrying device, and more particularly, to a fixing device for detachably fixing a carrying device to a passenger device. 
     2. Description of the Prior Art 
     In daily life, various passenger devices may be used, such as racks, child carriages carts for grocery shopping. A carrying device may be arranged on a passenger device for carrying person or object, such as a child seat, a child recliner, or a food basket. 
     SUMMARY OF THE DISCLOSURE 
     A purpose of the disclosure is to provide fixing device for detachably fixing a carrying device to a passenger device. As long as the user performs an unlocking operation, even if the user does not remove the carrying device from the passenger device, the fixing device will still remain in the unlocked state, and subsequently, when the user needs to remove the carrying device, there is no need to repeat the unlocking operation. 
     As specifically embodied and generally described herein, in order to achieve these and other advantages according to the disclosure, a fixing device for detachably fixing a carrying device to a passenger device is proposed. The fixing device includes: an engaging mechanism, disposed on one of the carrying device and the passenger device, and an engaging seat, disposed on the other one of the carrying device and the passenger device, wherein after the engaging mechanism is engaged into the engaging seat, the engaging mechanism and the engaging seat are able to be locked or unlocked, and wherein an unlocked state holding mechanism is disposed in the engaging mechanism, and after the engaging mechanism and the engaging seat are unlocked, the unlocked state holding mechanism is able to hold the engaging mechanism and the engaging seat in an unlocked state. 
     In an embodiment, the engaging mechanism includes a first locking member movable between a locked position and an unlocked position, and the engaging seat includes a second locking member being able to be locked with the first locking member, when the first locking member is in the locked position, the first locking member is locked with the second locking member to prevent the engaging mechanism from being separated from the engaging seat; and when the first locking member is in the unlocked position, the first locking member and the second locking member are unlocked to allow the engaging mechanism to be separated from the engaging seat. 
     In an embodiment, the engaging mechanism further includes an unlocking member disposed on the engaging mechanism, the unlocking member is able to be operated from an outside of the engaging mechanism to move from a first position to a second position, and when the unlocking member moves from the first position to the second position, the unlocking member is able to drive the first locking member to move from the locked position to the unlocked position. 
     In an embodiment, an engagement holding portion is disposed on the unlocking member, the unlocked state holding mechanism includes an unlocking holder located in the engaging mechanism, the unlocking holder includes a locking engagement hole and an unlocking engagement hole located on a surface of the unlocking holder facing the unlocking member, and the unlocking holder is able to move between a disengaged position and an engaged position, and wherein when the unlocking holder is in the disengaged position, neither the locking engagement hole nor the unlocking engagement hole of the unlocking holder engages with the engagement holding portion, and when the unlocking holder is in the engaged position, one of the locking engagement hole and the unlocking engagement hole of the unlocking holder is engaged with the engagement holding portion to restrict the unlocking member in the first position or the second position. 
     In an embodiment, when the unlocking holder is in the disengaged position, the unlocking holder is separated from the unlocking member by a predetermined distance. 
     In an embodiment, the unlocking holder further includes a boss, and when the unlocking holder is in the disengaged position, the boss extends out of the engaging mechanism, when the engaging mechanism is engaged into the engaging seat, a wall of the engaging seat presses the boss, such that the unlocking holder moves to the engaged position. 
     In an embodiment, a convex rib is disposed on an inner side of the wall of engaging seat at a position corresponding to the boss, and when the engaging mechanism is engaged into the engaging seat, the convex rib presses the boss, such that the unlocking holder moves to the engaged position. 
     In an embodiment, the unlocking holder is connected to an unlocked state holding elastic member, and the unlocked state holding elastic member drives the unlocking holder to move to the disengaged position. 
     In an embodiment, the locking engagement hole and the unlocking engagement hole communicate with each other through a first notch, and a width of the first notch is set to be smaller than diameters of the locking engagement hole and the unlocking engagement hole and smaller than a diameter of the engagement holding portion. 
     In an embodiment, at least a part of the unlocking holder that forms the first notch is elastic, such that when the unlocking member is moved from the first position to the In the second position under an external force, the engagement holding portion arranged on the unlocking member can overcome a resistance and move from the locking engagement hole to the unlocking engagement hole via the first notch. 
     In an embodiment, the engaging seat is a hollow casing having an opening, and the second locking member is a locking hole on the hollow casing. The first locking member includes: a locking protrusion, being able to extend out of the engaging mechanism to be locked with the locking hole of the engaging seat or to retract back inside the engaging mechanism to be unlocked with the locking hole of the engaging seat; a first pivot, located at one end of the first locking member, and pivotally disposed on the engaging mechanism such that the first locking member is able to be pivoted between the locked position and the unlocked position around the first pivot; and a movable portion, located at the other one end of the first locking member, wherein the movable portion is able to be driven by the unlocking member, so as to cause the first locking member to be pivoted from the locked position to the unlocked position, thereby causing the locking protrusion to be retracted back into the engaging mechanism to be unlocked with the locking hole of the engaging seat. 
     In an embodiment, the unlocking member includes: a pressing portion, located at one end of the unlocking member and exposed to an outside of the engaging mechanism; sa second pivot, located in a middle of the unlocking member and pivotally disposed on the engaging mechanism, such that the unlocking member is able to be pivoted between the first position and the second position around the second pivot; and a driving portion, located at the other one end of the unlocking member, being in contact with the first locking member and able to drive the first locking member to move from the locked position to the unlocked position. 
     In an embodiment, the engaging seat is a hollow casing having an opening, and the second locking member is a locking hole on the hollow casing. The first locking member includes: a locking protrusion, being able to extend out of the engaging mechanism to be locked with the locking hole of the engaging seat, or retract back inside the engaging mechanism to be unlocked with the locking hole of the engaging seat; a first pivot, located in a middle of the first locking member, and can be pivotally disposed in a pivoting hole of the engaging mechanism, such that the first locking member is able to be pivoted between the locked position and the unlocked position around the first pivot; and a pressing portion, located at the other one end of the first locking member and exposed to an outside of the engaging mechanism. 
     In an embodiment, holding protrusion is disposed on the first locking member, and the unlocked state holding mechanism includes a locked state holding hole and an unlocked state holding hole disposed at corresponding position of the engaging mechanism, wherein when the first locking member is in the locked position, the holding protrusion is located in the locked state holding hole, so as to restrict the first locking member in the locked position; when the first locking member is in the unlocked position, the holding protrusion is located in the unlocked state holding hole, so as to restrict the first locking member in the unlocked position; and wherein the locked state holding hole and the unlocked state holding hole are communicated through a second notch, and a width of the second notch is set to be smaller than diameters of the locked state holding hole and the unlocked state holding hole and smaller than a diameter of the holding protrusion. 
     In an embodiment, a part of the engaging mechanism that forms the second notch is elastic, such that when the first locking member is moved from the locking position to the unlocked position under an external force, the holding protrusion can overcome a resistance to move from the locked state holding hole to the unlocked state holding hole. 
     In an embodiment, the engaging seat is a hollow casing having an opening, the engaging mechanism has a fixing portion and an engaging portion extending from the fixing portion, wherein the fixing portion is used to fix the engaging mechanism to the carrying device, the engaging portion can enter and exit the hollow casing via the opening, so as to realize engaging and disengaging between the engaging mechanism and the engaging seat. 
     In an embodiment, the engaging seat or the engaging mechanism fixed to the cart are provided by a plurality, and the plurality of the engaging seats or the plurality of the engaging mechanisms are respectively fixed to different positions on the cart, such that the carrying device can be fixed to the different positions on the cart. 
     In an embodiment, a spring positioning member is disposed on a bottom of the engaging mechanism, and the spring positioning member is connected to a positioning elastic member, when the engaging mechanism is engaged into the engaging seat and the first locking member is locked with the second locking member, the spring positioning member retracts into the engaging mechanism, and the positioning elastic member is compressed; and after the first locking member and the second locking member are unlocked, the positioning elastic member is able to lift up the engaging mechanism and the carrying device. 
     In another solution, the disclosure proposes a passenger device that uses the fixing device mentioned above. 
     In yet another solution, the disclosure proposes a carrying device that uses the fixing device mentioned above. 
     The beneficial effect of the disclosure is that, by the fixing device according to the disclosure, the carrying device can be fixed to the cart more safely, and as long as the user performs an unlocking operation, even if the user does not remove the carrying device from the passenger device, the fixing device will still remain in the unlocked state, and subsequently, when the user needs to remove the carrying device, there is no need to repeat the unlocking operation. 
     From the following detailed description of the disclosure in combination of the accompanying drawings, the foregoing and other purposes, features, aspects and advantages of the disclosure will become more apparent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included herein to provide a further understanding of the disclosure, and are incorporated into this specification to constitute a part of this specification. The drawings illustrate embodiments of the disclosure, and are used together with the following description to illustrate the concept of the disclosure. 
       In the drawings: 
         FIG. 1A  is a perspective view of a carrying device after being fixed to a cart by a fixing device according to the disclosure. 
         FIG. 1B  is a perspective view of the carrying device before being fixed to a rack by the fixing device according to the disclosure. 
         FIG. 2  is a perspective view of a cart in  FIG. 1A  after the carrying device is detached. 
         FIG. 3  is a perspective view of the carrying device in  FIG. 1A . 
         FIG. 4  is a perspective view of a frame structure of the carrying device in  FIG. 1A . 
         FIG. 5  is a perspective view of the frame structure of the carrying device fixed to a cart by the fixing device according to the disclosure. 
         FIG. 6  is an exploded perspective view of the frame structure of the carrying device and the cart. 
         FIG. 7  shows an engaging seat of the fixing device according to an embodiment of the disclosure. 
         FIG. 8  shows an internal structure of an engaging mechanism according to a first preferred embodiment of the disclosure when a first locking member is in a locked position in a partially sectional manner. 
         FIG. 9  shows the internal structure of the engaging mechanism according to the first preferred embodiment of the disclosure when the first locking member is in a unlocked position in a partially sectional manner. 
         FIG. 10  is a perspective view showing the internal structure of the engaging mechanism according to the first preferred embodiment of the disclosure. 
         FIG. 11  is a perspective view of an unlocking member according to the first preferred embodiment of the disclosure. 
         FIG. 12  is a perspective view of an unlocking holder according to the first preferred embodiment of the disclosure. 
         FIG. 13  shows a state in which a locking engagement hole of the unlocking holder is engaged with an engagement holding portion according to the first preferred embodiment of the disclosure in a partially sectional manner. 
         FIG. 14  shows a state in which an unlocking engagement hole of the unlocking holder is engaged with the engagement holding portion according to the first preferred embodiment of the disclosure in a partially sectional manner. 
         FIG. 15  shows a state in which the unlocking holder is in a disengaged position according to the first preferred embodiment of the disclosure in a partially sectional manner. 
         FIG. 16  shows a state in which the unlocking holder is in an engaged position according to the first preferred embodiment of the disclosure in a partially sectional manner. 
         FIG. 17  is a perspective view of the first locking member according to a second preferred embodiment of the disclosure. 
         FIG. 18  is a perspective view showing the internal structure of the engaging mechanism according to the second preferred embodiment of the disclosure. 
         FIG. 19  shows a state of the internal structure of the engaging mechanism according to the second preferred embodiment of the disclosure when the first locking member is in the locked position in a partially sectional manner. 
         FIG. 20  shows a state of the internal structure of the engaging mechanism according to the second preferred embodiment of the disclosure when the first locking member is in the unlocked position in a partially sectional manner. 
         FIG. 21  is a perspective view showing a spring positioning member located in the engaging mechanism. 
         FIG. 22  is an exploded perspective view showing the spring positioning member and the engaging mechanism. 
     
    
    
     DETAILED DESCRIPTION 
     In the existing passenger device, the carrying device and the passenger device are fixed together and cannot be separated; or, although the carrying device is detachably installed on the passenger device, the installation and detachment are inconvenient. For example, when the user detaches the carrying device from the passenger device, the carrying device needs to be removed while being unlocked, which causes the operation to be very inconvenient. 
     The disclosure will be described in detail below by referring to the accompanying drawings. 
     As shown in  FIGS. 1A and 1B , the disclosure relates to a fixing device for detachably fixing a carrying device  10  to a passenger device. 
     The passenger device can be various types of tools, such as a cart  20  (see  FIG. 1A ), a rack  30  (see  FIG. 1B ), a cart for grocery shopping or the like. Among them, the rack  30 , in  FIG. 1B  can be a support device for child, such as a high chair frame body, which includes two legs  31 ,  32  and connecting parts  33  connecting the two legs. The two legs  31 ,  32  can be pivoted in respect to the connecting parts  33  to change an angle between the two legs, and the connecting parts  33  can maintain the two legs  31 ,  32  at any angle, thereby adjusting a height of the connecting parts  33 . However, for ease of description, the cart  20  in  FIG. 1A  will be used as an example to describe the passenger device. 
     The carrying device  10  may be a carrying structure for carrying people or things, such as a child seat, a child recliner, or a storage basket, which is placed on the cart  20 . The carrying device  10  is detachably fixed to the cart  20  by a fixing device, such that when the fixing device is locked, it can ensure the carrying device  10  and the cart  20  will not be separated, so as to ensure the person or things carried by the carrying device  10  will not fall out; and when the fixing device is unlocked, the carrying device  10  can be easily removed from the cart  20 . 
     Next, the fixing device according to the disclosure will be described in detail. 
     As can be best seen in  FIGS. 2 and 3 , the fixing device of the disclosure includes two parts that are respectively fixed on the carrying device  10  and the cart  20 , that is, an engaging mechanism  100  and an engaging seat  200 . The engaging mechanism  100  is detachably engaged into the engaging seat  200 , such that the carrying device  10  is detachably fixed to the cart  20 . It should be understood, although the drawings show the situation where the engaging seat  200  is fixed to the cart  20 , and the engaging mechanism  100  is fixed to the carrying device  10 , as a replacement, the engaging seat  200  may also be fixed to the carrying device  10 , and the engaging mechanism  100  may also be fixed to the cart  20 , as long as the engaging mechanism  100  is detachably engaged into the engaging seat  200 , such replacement will not affect the use effect of the disclosure. For ease of description, the disclosure will be illustrated by taking the situation where the engaging seat  200  is fixed to the cart  20  and the engaging mechanism  100  is fixed to the carrying device  10  as an example. 
     In addition, it should be specifically noted, in the embodiment shown in  FIG. 1B , the engaging seat  200  may be fixed to connecting parts  33  of the rack  30 , so, after the engaging mechanism  100 , which is fixed to the carrying device  10 , is engaged into the engaging seat  200 , the rack  30  can stably support the carrying device  10 . 
     In addition, the disclosure may employ a plurality of the engaging seats  200 , and these engaging seats  200  are respectively fixed to a plurality of positions of the cart  20 . For example, in the embodiment shown in  FIGS. 1A and 2 , one set (two) of engaging seats  200  are fixed to a handle frame  21  of the cart  20 , and the other set (two) of the engaging seats  200  are fixed to a front wheel frame  22  of the cart  20 . Or alternatively, the other set (two) of the engaging seats  200  may also be fixed to a rear wheel frame  23  of the cart  20 . By utilizing a plurality of the engaging seats  200  and fixing the plurality of the engaging seats  200  to a plurality of positions of the cart  20 , the carrying device  10  can be fixed to different positions of the cart  20 , so as to meet different requirements of the user. 
     Similarly, the disclosure may employ a plurality of the engaging mechanisms  100 , and these engaging mechanisms  100  are respectively fixed to a plurality of positions on the carrying device  10 . Of course, due to cost considerations, generally one set (two) of the engaging mechanisms  100  are used, which are respectively fixed to both sides of the carrying device  10 , as shown in  FIGS. 1A and 3 , such that the carrying device  10  is stably supported. Advantageously, the engaging mechanisms  100  are fixed to a frame structure  11  of the carrying device  10 , as best seen in  FIGS. 4-6 . 
     Hereinafter, how the engaging mechanism  100  can be detachably engaged into the engaging seat  200  will be described. 
     The fit between the engaging mechanism  100  and the engaging seat  200  is a concave-convex fit. In this concave-convex fit, a bulge of a convex part can be inserted into and withdrawn from a recess of a concave part, so as to realize engaging and disengaging between the two parts. 
       FIGS. 1A-7  show the engaging mechanism  100  and the engaging seat  200  according to a preferred embodiment of the disclosure. The engaging seat  200  is a hollow casing  202  having an opening  201  (see  FIG. 7 ), and forms a concave part in a concave-convex fit. The engaging mechanism  100  has a fixing portion  101  and an engaging portion  102  (see  FIGS. 3 and 4 ), and forms a convex part in the concave-convex fit. Among them, the fixing portion  101  is used to fix the engaging mechanism  100  to the carrying device  10 , and the engaging portion  102  can enter an interior of the hollow casing  202  through the opening  201 , so as to realize a engaging of the engaging mechanism  100  and the engaging seat  200 , as shown in  FIG. 5 . On the other hand, the engaging portion  102  can also be withdrawn from the interior of the hollow casing  202 , so as to realize a separating of the engaging mechanism  100  and the engaging seat  200 , as shown in  FIG. 6 . The fixing portion  101  and the engaging portion  102  can be integrally formed, or they can be made separately and then assembled together. The engaging mechanism  100  includes a housing for containing various components therein. The housing includes openings thereon, so some components contained therein may be exposed to the outside through the openings or interact with other components other than the engaging mechanism  100 . 
     It should be understood, the engaging seat  200  and the engaging mechanism  100  can also adopt other concave-convex fit structures that can be engaged and separated from each other than the preferred embodiment. For example, the engaging seat  200  may have a groove, and the engaging mechanism  100  may have a protrusion, moreover, the protrusion can be inserted into and withdrawn from the groove, so as to realize engaging and disengaging between the engaging mechanism  100  and the engaging seat  200 . 
     In order to ensure that after the engaging mechanism  100  and the engaging seat  200  are engaged to each other, they will not accidentally separate, it is necessary to dispose a locking member between he engaging mechanism  100  and the engaging seat  200 , such that they can be locked or unlocked. It should be noted, in the disclosure, the engaging mechanism  100  can be inserted into the engaging seat  200  and the engaging mechanism  100  can be withdrew from the engaging seat  200 , such a fitting is called “engaged.” Moreover, the engaging mechanism  100  and the engaging seat  200  are kept in an engaged state by means of a locking member, and the engaging mechanism  100  cannot arbitrarily withdraw from the engaging seat  200 , such a fitting is called “locked.” Hereinafter, the locking member between the engaging mechanism  100  and the engaging seat  200  will be described in detail. 
     According to the disclosure, the engaging mechanism  100  includes a first locking member  110  movable between a locked position and an unlocked position, and the engaging seat  200  includes a second locking member  210  that can be locked with the first locking member  110 . When the first locking member  110  is in the locked position, the first locking member  110  and the second locking member  210  are locked, so as to prevent the engaging mechanism  100  from being separated from the engaging seat  200 ; and when the first locking member  110  is in the unlocked position, the first locking member  110  and the second locking member  210  are unlocked, so as to allow the engaging mechanism  100  to be separated from the engaging seat  200 . 
       FIGS. 7-10  show the first locking member  110  and the second locking member  210  according to the first preferred embodiment of the disclosure. Among them, as shown in  FIGS. 7-9 , the second locking member  210  is a locking hole on a hollow casing  202  of the engaging seat  200 . The first locking member  110  includes a locking protrusion  111 . The locking protrusion  111  can extend out of the engaging mechanism  100  to be locked with the locking hole of the engaging seat  200 , or retract back inside the engaging mechanism  100  to be unlocked with the locking hole of the engaging seat  200 . 
     In addition, the first locking member  110  is also connected to a locking elastic member  112 . The locking elastic member  112  drives the first locking member  110  to move to the locked position, that is, driving the locking protrusion  111  to extend out of the engaging mechanism  100  to be locked with the locking hole of the engaging seat  200 . The locking elastic member  112  may be a member with elastic force, such as a spring or elastic rubber. 
     In the situation of the first preferred embodiment, when the user fixes the carrying device  10  to the cart  20 , the engaging mechanism  100  will be engaged into the engaging seat  200 , and in this process, a wall of the engaging seat  200  may press the locking protrusion  111 , so as to force the locking protrusion  111  to overcome the elastic force of the locking elastic member  112  and retract into the engaging mechanism  100 . After the engaging mechanism  100  is completely engaged into the engaging seat  200 , on the one hand, the first locking member  110  tends to move to the locked position under the elastic force of the locking elastic member  112 ; on the other hand, when the locking protrusion  111  is aligned with the second locking member  210  on the engaging seat  200 , that is, the locking hole, the locking protrusion  111  is no longer pressed by the wall of the engaging seat  200 , such that the first locking member  110  is moved to the locked position, and the locking protrusion  111  protrudes from the locking hole on the engaging seat  200  and is locked with the locking hole, thereby locking the engaging mechanism  100  into the engaging seat  200 , and accordingly locking the carrying device  10  to the cart  20  also. 
     It should be understood, the first locking member  110  and the second locking member  210  may also utilize other locking and fitting structures different from the first preferred embodiment. For example, the second locking member  210  may be a locking protrusion on an inner side of the wall of the engaging seat  200 , and a corresponding position of the first locking member  110  includes a locking concave part capable of engaging the locking protrusion; or alternatively, the second locking member  210  may be a protrusion having a shape of a positive cone on the inner side of wall of the engaging seat  200 , and the corresponding position of the first locking member  110  includes a protrusion having a shape of an inverted cone which can engage the locking protrusion, and so on. In these locking and fitting structures, the locking elastic member  112  can be arranged similarly to drive the first locking member  110  to approach the second locking member  210  and to be locked with the second locking member  210 . 
     Further, the movement of the first locking member  110  between the locked position and the unlocked position can be implemented in a variety of ways. 
     As shown in  FIGS. 8-10 , according to the first preferred embodiment of the disclosure, the first locking member  110  further includes a first pivot  113  located at one end of the first locking member  110 . The first pivot  113  is pivotally disposed on the engaging mechanism  100 , and preferably between the fixing portion  101  and the engaging portion  102  of the engaging mechanism  100 , such that the first locking member  110  can be pivoted around the first pivot  113  between the locked position and the unlocked position. The first locking member  110  further includes a movable portion  114 , which is advantageously located at the other end of the first locking member  110 . 
     The first locking member  110  is usually kept in the locked position under an action of the locking elastic member  112 . When the user applies a force to the movable portion  114 , the first locking member  110  can overcome the elastic force of the locking elastic member  112  to be pivoted from the locked position to the unlocked position around the first pivot  113 , thereby causing the locking protrusion  111  to be retracted back into the engaging mechanism  100  and unlocked with the second locking member  210  of the engaging seat  200 . 
     In order to facilitate the user to apply force to the movable portion  114  of the first locking member  110 , the engaging mechanism  100  further includes an unlocking member  130 . The unlocking member  130  can be operated from the outside of the locking mechanism  100 , preferably by a pressing operation, so as to move between a first position and a second position. Moreover, the unlocking member  130  contacts the first locking member  110  and is arranged such that when the unlocking member  130  is pivoted from the first position to the second position, the unlocking member  130  drives the first locking member  110  to move from the locked position to the unlocked position; and when the unlocking member  130  is in the second position, the unlocking member  130  can keep the first locking member  110  in the unlocked position, as shown in  FIG. 9 ; furthermore, when the unlocking member  130  is in the first position, the unlocking member  130  cannot prevent the first locking member  110  from moving from the locked position to the unlocked position. 
       FIGS. 8-11  show the unlocking member  130  according to the first preferred embodiment of the disclosure, where the unlocking member  130  includes: a pressing portion  131 , located at one end of the unlocking member  130  and exposed to the outside of the engaging mechanism  100  for facilitating the user to press; a second pivot  132 , located in the middle of the unlocking member  130 , the second pivot  132  is pivotally disposed on the engaging mechanism  100 , and preferably between the fixing portion  101  of the engaging mechanism  100  and the engaging portion  102 , such that the unlocking member  130  can be pivoted from the first position to the second position around the second pivot  132 ; and a driving portion  133 , located at the other end of the unlocking member  130 , the driving portion  133  can be in contact with the movable portion  114  of the first locking member  110  and is arranged such that when the unlocking member  130  is pivoted from the first position to the second position, the driving portion  133  brings the movable portion  114  of the first locking member  110  to move, thereby driving the first locking member  110  from the locked position to the unlocked position; when the unlocking member  130  is in the second position, the driving portion  133  can keep the first locking member  110  in the unlocked position, as shown in  FIG. 9 ; and when the unlocking member  130  is in the first position, the driving portion  133  cannot prevent the first locking member  110  from moving from the locked position to the unlocked position. It should be understood, although an embodiment about action modes between the unlocking member  130  and the first locking member  110  has been described above, the disclosure is not limited to this. Rather, the unlocking member  130  and the first locking member  110  both can adopt other structures capable of realizing their functions, which will be described later, so there are other action modes between the unlocking member  130  and the first locking member  110 . 
     In the situation of the first preferred embodiment, if the user prepares to remove the carrying device  10  from the cart  20 , it is necessary to separate the engaging mechanism  100  from the engaging seat  200 . At this time, the unlocking member  130  is in the first position, and the first locking member  110  is in the locked position, as shown in  FIG. 8 . When the user presses the pressing portion  131  of the unlocking member  130  in the direction of the arrow, the pressing portion  131  moves to the left under the pressing force. Therefore, the unlocking member  130  moves from the first position to the second position around the second pivot  132 , such that the driving portion  133  moves to the right, thereby driving the movable portion  114  of the first locking member  110  to move to the right, and the locking protrusion  111  accordingly moves to the right to be unlocked with the locking hole of the engaging seat  200 , thereby moving the first locking member  110  to unlocked position, as shown in  FIG. 9 . As a result, the engaging mechanism  100  can be separated from the engaging seat  200  upward, and the carrying device  10  can be removed from the cart  20  accordingly. 
     When the user no longer presses, in order to enable the unlocking member  130  to return from the second position to the first position, the unlocking member  130  may be connected to a return elastic member  134 , as best seen in  FIGS. 8-10 . The return elastic member  134  may be a member having an elastic force, such as a spring or elastic rubber. 
     It should be understood, according to the disclosure, the implementation modes of moving the first locking member  110  from the locked position to the unlocked position is not limited to the above-mentioned embodiment. 
     For example, the first locking member  110  is not limited to performing a pivoting movement, rather, it can also perform a translational movement, for example, a guide rail mechanism may be provided between the first locking member  110  and the inner side of wall of the engaging mechanism  100 , such that the first locking member  110  can translate between the locked position and the unlocked position. 
     For another example, the unlocking member  130  is not limited to performing a pivoting movement either, and it can also perform a translational movement, for example, a guide rail mechanism may be provided between the unlocking member  130  and the inner side of wall of the engaging mechanism  100 , such that the unlocking member  130  can translate between the first position and the second position, and the translation of the unlocking member  130  can also drive the first locking member  110  to move between the locked position and the unlocked position. 
     For a further example, the separate unlocking member  130  may not be even be provided, instead, an extended portion may be disposed on the first locking member  110 , the extended portion may be extended out of the engaging mechanism  100 , so the user may operate the first locking member  110  through the extended portion, so as to move the first locking member  110  between the locked position and the unlocked position.  FIGS. 17-20  show a second preferred embodiment according to the disclosure. In this preferred embodiment, no separate unlocking member is provided, or in other words, the unlocking member is formed as a part of the first locking member. Among them, the locking protrusion  111 ′ is located at one end of the first locking member  110 ′, and the locking protrusion  110 ′ can also extend out of the engaging mechanism  100  to be locked with the locking hole of the engaging seat  200 , or retract back inside the engaging mechanism  100  to be unlocked with the locking hole of the engaging seat  200 . The first pivot  113 ′ is located in the middle of the first locking member  110 ′, and the first pivot  113 ′ is pivotally arranged in a pivoting hole  103  on the engaging mechanism  100  (see  FIG. 16 ), such that the first locking member  110 ′ can be pivoted between the locked position and the unlocked position around the first pivot  113 ′; moreover, the pressing portion  131 ′ extending out of the engaging mechanism  100  is arranged at the other end of the first locking member  110 ′, and the pressing portion  131 ′ may play an unlocking role. 
       FIG. 19  shows the first locking member  110  in the locked position. When the user presses the pressing portion  131 ′ of the first locking member  110 ′ in the direction of the arrow, the pressing portion  131 ′ moves to the left under the pressing force, so the first locking member  110 ′ is pivoted from the locked position to the unlocked position around the first pivot  113 ′, thereby causing the locking protrusion  111 ′ to move to the right to be unlocked with the locking hole of the engaging seat  200 , such that the first locking member  110 ′ is in the unlocked position, as shown in  FIG. 20 . 
     When the user no longer presses, in order to enable the first locking member  110 ′ to return from the unlocked position to the locked position, the first locking member  110 ′ may be connected to a return elastic member  134 ′, as best seen in  FIGS. 19, 20, and 22 . The return elastic member  134 ′ may be a member having a elastic force, such as a spring or elastic rubber. 
     Hereinafter, an important design of the disclosure will be described. 
     In order to further facilitate the user to remove the carrying device  10  from the cart  20 , the disclosure particularly provides an unlocked state holding mechanism in the engaging mechanism  100 . After the engaging mechanism  100  is unlocked with the engaging seat  200 , the unlocked state holding mechanism can hold the engaging mechanism  100  and the engaging seat  200  in an unlocked state. Specifically, after the user presses the pressing portion  131  to move the first locking member  110  to the unlocked position, the unlocked state holding mechanism can hold the first locking member  110  in the unlocked position. In such situation, even if the user no longer presses the pressing portion  131  of the unlocking member  130 , the first locking member  110  and the second locking member  210  still remain in an unlocked state. Therefore, although the engaging mechanism  100  is located in the engaging seat  200 , the engaging mechanism  100  and the engaging seat  200  can be separated at any time, so the user can directly remove the carrying device  10  from the cart  20  without having to perform the unlocking operation again or having to removing the carrying device and unlocking the fixing device at the same time, which causes inconvenience in operation. 
       FIGS. 10 and 12-16  show the unlocked state holding mechanism according to the first preferred embodiment of the disclosure. The unlocked state holding mechanism includes an unlocking holder  120  located in the engaging mechanism  100 , and the unlocking member  130  includes an engagement holding portion  135 . The unlocking holder  120  includes a locking engagement hole  121  and an unlocking engagement hole  122 . As best seen in  FIG. 12 , the locking engagement hole  121  and the unlocking engagement hole  122  are both located on a surface of the unlocking holder  120  facing the unlocking member  130 . The locking engagement hole  121  and the unlocking engagement hole  122  respectively corresponds to the position of the engagement holding portion  135  when the unlocking member  130  is in the first position or in the second position. 
     The engagement holding portion  135  may adopt various structures such as protrusions, short posts, etc., as long as it can engage with the locking engagement hole  121  and the unlocking engagement hole  122 . 
     The unlocking holder  120  can move between a disengaged position and an engaged position. Among them, when the unlocking holder  120  is in the disengaged position, neither the locking engagement hole  121  nor the unlocking engagement hole  122  of the unlocking holder  120  is engaged with the engagement holding portion  135 , so at this time, the movement of the unlocking member  130  is not restricted by the unlocking holder  120 . 
     When the unlocking holder  120  is in the engaged position, the locking engagement hole  121  of the unlocking holder  120  engages with the engagement holding portion  135 , so as to restrict the unlocking member  130  in the first position, as shown in  FIG. 13 ; or the unlocking engagement hole  122  engages with the engagement holding portion  135 , so as to restrict the unlocking member  130  in the second position, as shown in  FIG. 14 . In both situations, the movement of the unlocking member  130  is restricted by the unlocking holder  120 . 
     The disclosure may adopt various ways to realize the movement of the unlocking holder  120  between the disengaged position and the engaged position. For example, a member similar to the unlocking member  130  may be arranged to be linked with the unlocking holder  120  and has a part exposed to the outside of the engaging mechanism  100 , such that the member can be operated from the outside of the engaging mechanism  100 , thereby brining the unlocking holder  120  to move between the disengaged position and the engaged position. For another example, an extended portion may be further disposed on the unlocking holder  120 . The extended portion may extend out of the engaging mechanism  100 , such that the user can operate the unlocking holder  120  to move between the disengaged position and the engaged position through the extended portion. 
     According to the first preferred embodiment of the disclosure, an automatic mode is provided to realize the unlocking holder  120  moving between the disengaged position and the engaged position. By this automatic mode, the unlocking holder  120  can move automatically during the process of the engaging mechanism  100  being engaged into the engaging seat  200  and separated from the engaging seat  200 . 
     As can be best seen in  FIGS. 10 and 12 , the unlocking holder  120  includes a boss  124 . The boss  124  can extend out of the engaging mechanism  100 . As can be best seen in  FIGS. 10 and 13-14 , the unlocking holder  120  is connected to an unlocked state holding elastic member  125 , and the unlocked state holding elastic member  125  drives the unlocking holder  120  to move to the disengaged position. The unlocked state holding elastic member  125  may be a member having an elastic force such as a spring or elastic rubber. 
     In the situation of the first preferred embodiment, when the user does not place the carrying device  10  on the cart  20  or remove the carrying device  10  from the cart  20 , the engaging mechanism  100  is separated from the engaging seat  200 . At this time, the unlocking holder  120  moves to the disengaged position under the action of the unlocked state holding elastic member  125 , and the boss  124  extend out of the engaging mechanism  100 , as shown in  FIG. 15 . Since the movement of the unlocking member  130  is not restricted by the unlocking holder  120  at this time, the unlocking member  130  can move between the first position and the second position. 
     When the user places the carrying device  10  on the cart  20 , the wall of the engaging seat  200  will press the boss  124  to force the boss  124  to retract into the engaging mechanism  100  during the process of the engaging mechanism  100  being engaged into the engaging seat  200 , such that the unlocking holder  120  moves to the engaged position, and the locking engagement hole  121  is engaged with the engagement holding portion  135 , as shown in  FIG. 16 . 
     It should be noted here, as mentioned above, since the unlocking member  130  and the first locking member  110  are in contact with each other and are arranged such that when the unlocking member  130  is in the first position, the unlocking member  130  cannot prevent the first locking member  110  from moving from the locked position to the unlocked position. Therefore, during the process the user places the carrying device  10  on the cart  20 , even if the unlocking member  130  is restricted to the first position by the unlocking holder  120 , the first locking member  110  is still able to move from the locked position to the unlocked position. Specifically, during the process the engaging mechanism  100  being engaged into the engaging seat  200 , the wall of the engaging seat  200  will press the locking protrusion  111  of the first locking member  110 , forcing the locking protrusion  111  to overcome the elastic force of the locking elastic member  112  and retract into the engaging mechanism  100 , such that the first locking member  110  moves from the locked position to the unlocked position. 
     On the other hand, as mentioned above, since the unlocking member  130  and the first locking member  110  are also arranged such that when the unlocking member  130  is in the second position, the unlocking member  130  can keep the first locking member  110  in the unlocked position. Therefore, if the user prepares to remove the carrying device  10  from the cart  20 , it is necessary to unlock the engaging mechanism  100  and the engaging seat  200 . The user can operate the unlocking member  130  to move the unlocking member  130  to the second position, so the first locking member  110  is also moved to the unlocked position. In such situation, if the unlocking member  130  is restricted to the second position by the unlocking holder  120 , the first locking member  110  will also be restricted to the unlocked position. This function will make the user more convenient, because the user only needs to operate the unlocking member  130  once, for example, by pressing the pressing portion  131  of the unlocking member  130  once, the engaging mechanism  100  can be unlocked with the engaging seat  200  and remain in the unlocked state. After that, the user does not need to operate the unlocking member  130  again. Although the engaging mechanism  100  is engaged in the engaging seat  200 , the user can remove the carrying device  10  from the cart  20  at any time. 
     More advantageously, a convex rib  220  is arranged on the inner side of the wall of the engaging seat  200  at a position corresponding to the boss  124 . When the engaging mechanism  100  is engaged into the engaging seat  200 , the convex rib  220  will press the boss  124 , such that the unlocking holder  120  is moved to the engaged position. The arrangement of the convex rib  220  makes a movable stroke of the unlocking holder  120  longer, thereby ensuring the locking engagement hole  121  and the unlocking engagement hole  122  are engaged with the engagement holding portion  135 . 
     In the situation of the above-mentioned automatic mode, the unlocking holder  120  can automatically move, without the user&#39;s operation, between the disengaged position and the engaged position by pressing between the wall of the engaging seat  200  and the boss  124  as well as the action of the unlocked state holding elastic member  125 . Such automatic mode is convenient, however, a problem is created: after the engaging mechanism  100  is completely engaged into the engaging seat  200 , the first locking member  110  returns to the locked position under the elastic force of the elastic member  112 , and the unlocking holder  120  moves to the engaged position due to its boss  124  being pressed by the wall of the engaging seat  200 , such that the locking engagement hole  121  of the unlocking holder  120  is engaged with the engagement holding portion  135 . At this time, the unlocking member  130  is restricted to the first position by the unlocking holder  120  and cannot be moved to the second position, so the first locking member  110  cannot be driven from the locked position to the unlocked position, that is, the engaging mechanism  100  cannot be unlocked with the engaging seat  200 . 
     In order to solve this problem, the locking engagement hole  121  and the unlocking engagement hole  122  may be communicated through a first notch  123 , as shown in  FIG. 12-14 , such that the engagement holding portion  135  can move from the locking engagement hole  121  to the unlocking engagement hole  122  via the first notch  123 . Moreover, a width of the first notch  123  is set to be smaller than diameters of the locking engagement hole  121  and the unlocking engagement hole  122  and smaller than a diameter of the engagement holding portion  135 . In this way, the engagement holding portion  135  is prevented from easily moving between the locking engagement hole  121  and the unlocking engagement hole  122  via the first notch  123 , so as to maintain the function of the unlocking holder  120  restricting the unlocking member  130  to the first position or the second position. 
     At least a portion of the unlocking holder  120  that forms the first notch  123  is elastic, such that the engagement holding portion  135  has to overcome a considerable resistance to move from the locking engagement hole  121  to the unlocking engagement hole  122  via the first notch  123 . As a result, only when the unlocking member  130  is moved from the first position to the second position under an external force applied by the user, the engagement holding portion  135  arranged on the unlocking member  130  can move from the locking engagement hole  121  to the unlocking engagement hole  122  via the first notch  123 . 
     Here, it is possible to adopt a solution that the entire unlocking holder  120  is elastic, or it can also adopt a solution that only the part forming the first notch  123  is elastic, that is, the unlocking holder  120  may be composed of at least two parts, the part forming the first notch  123  is elastic, and the other part may be or may be not elastic. 
     It should be noted, the preferred solution of forming a communication between the locking engagement hole  121  and the unlocking engagement hole  122  through the first notch  123  is mainly used in the embodiment for the automatic mode described above, which causes the unlocking holder  120  to automatically move between the disengaged position and the engaged position (i.e., the unlocking holder  120  can automatically move between the disengaged position and the engaged position by the pressing force between the wall of the engaging seat  200  and the boss  124  and the force of the unlocked state holding elastic member  125 , without the user&#39;s manual operation). Such solution is not necessarily adopted in other embodiments. For example, in order to realize the unlocking holder  120  moving between the disengaged position and the engaged position, a member similar to the unlocking member  130  may be disposed, which is linked with the unlocking holder  120  and has a part exposed to the outside of the engaging mechanism  100 , such that the member can be operated from the outside of the engaging mechanism  100 , thereby brining the unlocking holder  120  to move between the disengaged position and the engaged position. For another example, an extended portion can be disposed on the unlocking holder  120 , the extended portion may extend out of the engaging mechanism  100 , such that the user can perform an operation on the unlocking holder  120  through the extended portion, thereby moving the unlocking holder  120  between the disengaged position and the engaged position. In those embodiments the user manually performs operations, since the unlocking holder  120  is not automatically moves between the disengaged position and the engaged position by the pressing force between the wall of the engaging seat  200  and the boss  124  and the force of the unlocked state holding elastic member  125 , it is unnecessary to adopt the preferred solution of forming the first notch  123  between the locking engagement hole  121  and the unlocking engagement hole  122 . 
       FIGS. 17-20  show the unlocked state holding mechanism according to the second preferred embodiment of the disclosure, which includes: a holding protrusion  115  disposed on the first locking member  110 ′; and a locked state holding hole  104  and an unlocked state holding hole  105  disposed at corresponding positions on the engaging mechanism  100 . Among them, when the first locking member  110 ′ is in the locked position, the holding protrusion  115  is located in the locked state holding hole  104 , so as to restrict the first locking member  110 ′ in the locked position, as shown in  FIG. 19 ; moreover, when the first locking member  110 ′ is in the unlocked position, the holding protrusion  115  is located in the unlocked state holding hole  105 , so as to restrict the first locking member  110 ′ in the unlocked position, as shown in  FIG. 20 . 
     In order to enable the first locking member  110 ′ to move between the locked position and the unlocked position, the locked state holding hole  104  and the unlocked state holding hole  105  communicate through a second notch  106 , as best seen in  FIG. 18 , such that the holding protrusion  115  can move from the locked state holding hole  104  to the unlocked state holding hole  105  via the second notch  106 . Moreover, a width of the second notch  106  is set to be smaller than the diameters of the locked state holding hole  104  and the unlocked state holding hole  105  and smaller than the diameter of the holding protrusion  115 . In this way, the holding protrusion  115  is prevented from easily moving between the locked state holding hole  104  and the unlocked state holding hole  105  via the second notch  106 , such that the function of the unlocked state holding mechanism of being able to restrict the first locking member  110 ′ in the locked position or the unlocked position is maintained. 
     Meanwhile, the part of the engaging mechanism  100  that forms the second notch  106  is elastic, for example, an elastic finger portion is formed, such that the holding protrusion  115  needs to overcome a considerable resistance to move from the locked state holding hole  104  to the unlocked state holding hole  105  via the second notch  106 . As a result, only when the first locking member  110 ′ is moved from the locked position to the unlocked position under the external force applied by the user, the holding protrusion  115  arranged on the first locking member  110 ′ can move from the locked state holding hole  104  to the unlocked state holding hole  105  via the second notch  106 . 
     Here, the part of the engaging mechanism  100  that forms the second notch  106  is elastic means, the engaging mechanism  100  may be composed of at least two parts, the part that forms the second notch  106  is elastic, a housing of the engaging mechanism  100  is not elastic, and the other part may be or may be not elastic. 
     As shown in  FIGS. 19-22 , a spring positioning member  140  is disposed on a bottom of the engaging mechanism  100 . The spring positioning member  140  is connected to a positioning elastic member  141 , see  FIGS. 19-20 and 22 . When the engaging mechanism  100  is engaged into the engaging seat  200 , and the first locking member  110 ′ and the second locking member  210  are locked, the spring positioning member  140  will retract into the engaging mechanism  100 , and the positioning elastic member  141  will be compressed, as shown in FIG.  19 . When the first locking member  110 ′ is unlocked with the second locking member  210 , the positioning elastic member  141  can lift up the engaging mechanism  100  and the carrying device  10 , as shown in  FIG. 20 , so that the user can more easily remove the carrying device  10  from the cart  20 . 
     The foregoing embodiments and advantages are only exemplary, and cannot be regarded as a limitation of the disclosure. The description herein is intended to be an example, not to limit the scope of the claims. For those skilled in the art, various alternatives, modifications and modifications are obvious. The features, structures, methods, and other characteristics of the exemplary embodiments described herein can be combined in various ways to obtain other and/or alternative exemplary embodiments. 
     Since the features of the disclosure can be embodied in various forms without departing from the characteristics of the disclosure, it should also be understood, the above-mentioned embodiments are not limited to any details described above, unless otherwise noted, rather, these embodiments should be interpreted broadly as being within the scope defined by the appended claims. Therefore, all modifications and alterations falling within the scope and limits of the claims or equivalent solutions of such scope and limits should be covered by the appended claims.