Patent Publication Number: US-2023160243-A1

Title: Coupling device and terminal equipment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority to Chinese Patent Application No. 202111407838.9 filed on Nov. 24, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     Terminal equipment, such as a mobile device, with a foldable screen has become a focus of competition among manufacturers of terminal equipment. In order to ensure a normal folding function of the screen of the terminal equipment, a hinge for coupling two middle frames is arranged at a position where a screen is folded. Since the screen has a certain thickness, a length of a front surface and a length of a back surface of the screen after being folded may be different, and thus wrinkles are formed in the screen after it is folded. This may cause damage to the screen and affect the normal use of the terminal equipment. 
     SUMMARY 
     The present disclosure relates to the field of mobile terminals and, more particularly, to a coupling device and terminal equipment. 
     A coupling device according to the embodiments of the present disclosure includes: a middle frame fixing member; a first transmission assembly rotatable relative to the middle frame fixing member during rotation of the middle frame fixing member; a second transmission assembly having a first end hinged to the first transmission assembly at a first hinge center and having a second end slidably coupled to the first transmission assembly. A rotation center of the first transmission assembly does not coincide with the first hinge center, and the second transmission assembly converts a rotation action of the first transmission assembly into a moving action along a second direction; and a third transmission assembly having a first end hinged to the second transmission assembly and having a second end and a third end both slidably coupled to the middle frame fixing member. The second end and the third end of the third transmission assembly are on two sides of the first end of the third transmission assembly, and the third end of the third transmission assembly pushes the middle frame fixing member to move towards a first side facing away from the first transmission assembly or a second side towards the first transmission assembly during the rotation of the middle frame fixing member. 
     Terminal equipment according to embodiments of another aspect of the present disclosure includes a screen and a coupling device coupled to the screen. The coupling device includes: a middle frame fixing member; a first transmission assembly rotatable relative to the middle frame fixing member during rotation of the middle frame fixing member; a second transmission assembly having a first end hinged to the first transmission assembly at a first hinge center and having a second end slidably coupled to the first transmission assembly. A rotation center of the first transmission assembly does not coincide with the first hinge center, and the second transmission assembly converts a rotation action of the first transmission assembly into a moving action along a second direction; and a third transmission assembly having a first end hinged to the second transmission assembly and having a second end and a third end both slidably coupled to the middle frame fixing member. The second end and the third end of the third transmission assembly are on two sides of the first end of the third transmission assembly, and the third end of the third transmission assembly pushes the middle frame fixing member to move towards a first side facing away from the first transmission assembly or a second side towards the first transmission assembly during the rotation of the middle frame fixing member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic view of terminal equipment according to an embodiment of the present disclosure. 
         FIG.  2    is a schematic view of a coupling device according to an embodiment of the present disclosure. 
         FIG.  3    is a schematic view showing power transmission of a coupling device according to an embodiment of the present disclosure. 
         FIG.  4    is an exploded view of a coupling device according to an embodiment of the present disclosure. 
         FIG.  5    is a schematic view of a middle frame fixing member according to an embodiment of the present disclosure. 
         FIG.  6    is a schematic view of a shaft sleeve according to an embodiment of the present disclosure. 
         FIG.  7    is a schematic view of a locking assembly according to an embodiment of the present disclosure. 
         FIG.  8    is a schematic view of a sliding block according to an embodiment of the present disclosure. 
         FIG.  9    is a schematic view showing that a synchronization member and a swing arm are assembled with each other according to an embodiment of the present disclosure. 
         FIG.  10    is a schematic view of a linkage according to an embodiment of the present disclosure. 
         FIG.  11    is a schematic view of a support member according to an embodiment of the present disclosure. 
         FIG.  12    is another schematic view of a support member according to an embodiment of the present disclosure. 
         FIG.  13    is a schematic view showing a transmission principle of a first transmission assembly according to an embodiment of the present disclosure. 
         FIG.  14    is a schematic view of a coupling device in a flattened state according to an embodiment of the present disclosure. 
         FIG.  15    is a schematic view showing that a coupling device rotates from a flattened state to a closed state according to an embodiment of the present disclosure. 
         FIG.  16    is a schematic view of a coupling device in a closed state according to an embodiment of the present disclosure. 
         FIG.  17    is a partially enlarged view of a coupling device in a closed state according to an embodiment of the present disclosure. 
         FIG.  18    is another schematic view of a coupling device in a closed state according to an embodiment of the present disclosure. 
         FIG.  19    is a sectional view of a coupling device in a flattened state according to an embodiment of the present disclosure. 
         FIG.  20    is a sectional view showing that a coupling device rotates from a flattened state to a closed state according to an embodiment of the present disclosure. 
         FIG.  21    is a sectional view of a coupling device in a closed state according to an embodiment of the present disclosure. 
         FIG.  22    is a schematic view showing a transmission principle of a third transmission assembly according to an embodiment of the present disclosure. 
         FIG.  23    is a schematic view of a support member and a middle frame fixing member according to an embodiment of the present disclosure. 
         FIG.  24    is a sectional view showing that a support member and a sliding block are in an assembled state according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present disclosure will be described in detail below, and examples of the described embodiments are shown in accompanying drawings. The following embodiments described with reference to the accompanying drawings are exemplary and are intended to explain the present disclosure rather than limit the present disclosure. 
     A coupling device  100  according to embodiments of the present disclosure will be described below with reference to the accompanying drawings. 
     As shown in  FIGS.  1  to  24   , the coupling device  100  according to the embodiments of the present disclosure includes a middle frame fixing member  2 , a first transmission assembly  3 , a second transmission assembly  4 , and a third transmission assembly  5 . 
     The middle frame fixing member  2  is configured to mount a middle frame, and may rotate along with the middle frame and a screen  8 . The first transmission assembly  3  may rotate relative to the middle frame fixing member  2  during rotation of the middle frame fixing member  2 , i.e., the rotation of the middle frame fixing member  2  may drive the first transmission assembly  3  to rotate. 
     A first end of the second transmission assembly  4  is hinged to the first transmission assembly  3  at a first hinge center, a rotation center of the first transmission assembly  3  does not coincide with the first hinge center, and a second end of the second transmission assembly  4  is slidably coupled to the first transmission assembly  3 . The second transmission assembly  4  is configured to convert a rotation action of the first transmission assembly  3  into a moving action along a second direction. It should be understood that the first transmission assembly  3  and the second transmission assembly  4  form a mechanism similar to a crank connecting rod. The first transmission assembly  3  and the second transmission assembly  4  are combined together, to convert a rotation action of the middle frame into a moving action along the second direction. 
     The third transmission assembly  5  has a bracket structure similar to a triangle. The third transmission assembly  5  has a first end, a second end and a third end. The first end of the third transmission assembly  5  is hinged to the second transmission assembly  4 , and the second end and the third end of the third transmission assembly  5  are slidably coupled to the middle frame fixing member  2 . The second end and the third end of the third transmission assembly  5  are located on two sides of the first end of the third transmission assembly  5  in the second direction. The third end of the third transmission assembly  5  is configured to push the middle frame fixing member  2  to move towards a first side facing away from the first transmission assembly  3  or a second side towards the first transmission assembly  3  during the rotation of the middle frame fixing member  2 . 
     It should be noted that based on a lever principle, the first end of the third transmission assembly serves as a fulcrum, and as the second transmission assembly  4  moves along the second direction, the second end and the third end of the third transmission assembly move along a direction opposite to the second direction. Thus, in a process of folding the screen  8 , the middle frame fixing member  2  drives the middle frame to move along the first side facing away from the first transmission assembly  3  or the second side towards the first transmission assembly  3 , so that a length of the screen  8  may be accurately compensated, avoiding wrinkles of the screen  8  and prolonging the service life of the screen  8 . 
     As shown in  FIG.  3    and  FIG.  13   , in some embodiments, the first transmission assembly  3  includes a first transmission member  31  and a second transmission member  32 . The first transmission member  31  is a helical gear shaft with a first helical tooth portion and is arranged along the second direction, and the first helical tooth portion is located at a middle position of the helical gear shaft. The second transmission member  32  is a helical gear with a second helical tooth portion. The first helical tooth portion meshes with the second helical tooth portion. The rotation of the second middle frame fixing member  2  may drive the first transmission member  31  to rotate, and in turn the first transmission member  31  drives the second transmission member  32  to rotate. 
     Further, the first end of the second transmission assembly  4  is hinged to the second transmission member  32  at the first hinge center, and the rotation center of the second transmission member  32  does not coincide with the first hinge center. In other words, the first hinge center is located on the second transmission member  32 , and the first hinge center is different from the rotation center of the second transmission member  32 . The second transmission member  32  may drive the first end of the second transmission assembly  4  to rotate with a larger rotation radius when the second transmission member  32  rotates. The second end of the second transmission assembly  4  is slidably coupled to the first transmission member  31 . Therefore, the second transmission assembly  4  and the first transmission assembly  3  form a crank connecting rod mechanism. The second transmission assembly  4  may convert the rotation action of the second transmission member  32  into the moving action along the second direction. 
     As shown in  FIG.  4   , specifically, the second transmission assembly  4  includes a synchronization member  41 , a shaft sleeve  42  and a linkage  43 . The synchronization member  41  is slidably coupled to the first transmission member  31 , the first end of the third transmission assembly  5  is hinged to the synchronization member  41 , and the synchronization member  41  may drive the third transmission assembly  5  to rotate when sliding on the first transmission member  31  along the second direction, so that the middle frame fixing member  2  is driven to move towards the first side facing away from the first transmission assembly  3  or the second side towards the first transmission assembly  3 . 
     The shaft sleeve  42  is slidably coupled to the first transmission member  31 , and the shaft sleeve  42  is coupled to the synchronization member  41 . A first end of the linkage  43  is hinged to the second transmission member  32  at the first hinge center, and a second end of the linkage  43  is hinged to the shaft sleeve  42 . Therefore, the rotation of the second transmission member  32  drives the first end of the linkage  43  to rotate, and the second end of the linkage  43  slides synchronously on the first transmission member  31  along the second direction and drives the synchronization member  41  to slide along the second direction simultaneously. 
     It should be noted that the synchronization member  41  includes a first synchronization sub-member  411  and a second synchronization sub-member  412 , and the first synchronization sub-member  411  and the second synchronization sub-member  412  are slidably arranged at two ends of the first transmission member  31  in the second direction. One or two, preferably two, third transmission assembles  5  may be provided. Respective first ends of the two third transmission assemblies  5  are hinged to the first synchronization sub-member  411  and the second synchronization sub-member  412 . 
     As shown in  FIG.  9   , the synchronization member  41  includes a first sliding portion  413 , a first connection portion  414 , and a first hinge portion  415 . The first sliding portion  413  has a hollow structure with an opening, and the opening of the first sliding portion  413  extends in the second direction. A side wall of the first sliding portion  413  includes a notch towards a side of the shaft sleeve  42 , the first sliding portion  413  and the shaft sleeve  42  are slidably fitted over the first transmission assembly  3 , and the shaft sleeve  42  is snapped in the notch, so that the shaft sleeve  42  may drive the first sliding portion  413  to slide synchronously along the first transmission member  31 . 
     The first connection portion  414  extends from the side wall of the first sliding portion  413  to a side facing away from the notch. The first connection portion  414  exhibits a step structure, and a biasing structure is arranged at a position of the first connection portion  414  close to the first hinge portion  415 . The first hinge portion  415  is located at an end of the first connection portion  414  away from the first sliding portion  413 , and the first hinge portion  415  is hinged to the first end of the third transmission assembly  5 , preferably by a pin connection. 
     Similarly, the shaft sleeve  42  includes a first shaft sub-sleeve  421  and a second shaft sub-sleeve  422 , and the first shaft sub-sleeve  421  and the second shaft sub-sleeve  422  are arranged corresponding to the first synchronization sub-member  411  and the second synchronization sub-member  412 . The first shaft sub-sleeve  421  and the second shaft sub-sleeve  422  are slidably arranged at the two ends of the first transmission member  31  in the second direction, the first shaft sub-sleeve  421  is snapped in a notch of the first synchronization sub-member  411 , and the second shaft sub-sleeve  422  is snapped in a notch of the second synchronization sub-member  412 . 
     As shown in  FIG.  6   , specifically, the shaft sleeve  42  includes a second sliding portion  423 , a second connection portion  424 , and a second hinge portion  425 . A structure of the second sliding portion  423  is similar to a structure of the first sliding portion  413 , and is also a hollow structure with an opening, and the opening of the second sliding portion  423  extends in the second direction. The second sliding portion  423  is slidably fitted over the first transmission assembly  3  and snapped in the notch of the first sliding portion  413 . 
     The second connection portion  424  is coupled to the second sliding portion  423  and extends in a first direction towards a side facing away from the first sliding portion  413 . The second hinge portion  425  is located at a side of the second connection portion  424  facing away from the second transmission member  32  and hinged to the second end of the linkage  43 , preferably by a pin connection. 
     Correspondingly, the linkage  43  includes a first sub-linkage  431  and a second sub-linkage  432 , and the first sub-linkage  431  and the second sub-linkage  432  correspond to the first shaft sub-sleeve  421  and the second shaft sub-sleeve  422 . A first end of the first sub-linkage  431  is hinged to the second transmission member  32 , and a second end of the first sub-linkage  431  is hinged to the second hinge portion  425  of the first shaft sub-sleeve  421 . A first end of the second sub-linkage  432  is hinged to the second transmission member  32 , and a second end of the second sub-linkage  432  is hinged to the second hinge portion  425  of the second shaft sub-sleeve  422 . 
     As shown in  FIG.  10   , the linkage  43  includes a third connection portion  433 , a first protrusion  434 , and a second protrusion  435 . The third connection portion  433  has a bent strip structure. The first protrusion  434  is arranged on a lower surface of a first end of the third connection portion  433 , and the first protrusion  434  is hinged to the second transmission member  32 . The second protrusion  435  is arranged on a lower surface of a second end of the third connection portion  433 , and the second protrusion  435  is hinged to the second hinge portion  425 . It should be noted that the third connection portion  433  may also use a through hole to replace the first protrusion  434  and the second protrusion  435 , and the second hinge portion  425  includes a protrusion corresponding to the through hole, so that the same purpose may also be achieved. 
     In some embodiments, the third transmission assembly  5  includes a swing arm  51  and a sliding block  53 . The swing arm  51  has a first end, a second end and a third end, and these three ends are arranged in a triangle. The first end of the swing arm  51  is hinged to the first hinge portion  415 , the second end of the swing arm  51  is slidably coupled to the middle frame fixing member  2  along the second direction, the sliding block  53  is slidably coupled to the middle frame fixing member  2  along the first direction, and the third end of the swing arm  51  is hinged to the sliding block  53 . 
     Thus, the synchronization member  41  drives the first end of the swing arm  51  to slide along the second direction when the synchronization member  41  slides along the second direction. At the same time, the second end of the swing arm  51  slides along the second direction on the middle frame fixing member  2 , and the third end of the swing arm  51  slides along the first direction on the middle frame fixing member  2  through the sliding block  53 , i.e., the third end of the swing arm  51  drives the middle frame fixing member  2  to move towards the first side facing away from the first transmission assembly  3  or the second side towards the first transmission assembly  3 . 
     Similarly, the swing arm  51  includes a first swing sub-arm  511  and a second swing sub-arm  512 , and the first swing sub-arm  511  and the second swing sub-arm  512  correspond to the first synchronization sub-member  411  and the second synchronization sub-member  412 . The first end of the first swing sub-arm  511  is hinged to the first hinge portion  415  of the first synchronization sub-member  411 , the first end of the second swing sub-arm  512  is hinged to the first hinge portion  415  of the second synchronization sub-member  412 , and the third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512  are each hinged to the sliding block  53 . The hinge mode is preferably a pin connection. 
     As shown in  FIG.  8   , in some embodiments, the sliding block  53  includes a sliding block body  531  and a connection segment  532 . The middle frame fixing member  2  includes a sliding groove along the first direction, and the sliding block body  531  is slidably arranged in the sliding groove. The connection segment  532  is coupled to the sliding block body  531 , and the connection segment  532  passes through the third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512 . 
     The connection segment  532  successively passes through the third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512 , to make them rotatably coupled. That is, the third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512  may rotate around the connection segment  532 . The third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512  rotate around the connection segment  532  when the sliding block body  531  slides in the sliding groove. In other words, the third end of the first swing sub-arm  511  and the third end of the second swing sub-arm  512  may drive the sliding block body  531  to slide in the sliding groove along the first direction and hence push the middle frame fixing member  2  to move along the first direction, when the first swing sub-arm  511  rotates relative to the first synchronization sub-member  411  and the second swing sub-arm  512  rotates relative to the second synchronization sub-member  412 . 
     As shown in  FIG.  11   ,  FIG.  12    and  FIG.  17   , in some embodiments, the coupling device  100  further includes a support member  7 . The support member  7  has a plate-shaped structure and supports the screen  8 . A side of the support member  7  away from the first transmission assembly  3  in the first direction includes an arc insert  71 , the middle frame fixing member  2  includes an arc groove  211 , and the insert  71  is rotatably fitted in the arc groove  211 . The third transmission assembly  5  is slidably coupled to the support member  7  to drive the support member  7  to rotate relative to the middle frame fixing member  2 . 
     The insert  71  is rotatably fitted in the arc groove  211 , so that the support member  7  may rotate along a track of the arc groove  211  when the middle frame fixing member  2  is in different positions. Therefore, the support member  7  may guide the screen  8  to allow s the screen  8  to be in a suitable state. 
     For example, the coupling device  100  according to the embodiments of the present disclosure is coupled to the screen  8  to form a foldable mobile phone or a foldable tablet computer. A surface of the support member  7  facing towards the screen  8  is parallel or substantially parallel to the screen  8  when the middle frame fixing member  2  is in a flattened state, so that the screen  8  is in an unfolded state. The surface of the support member  7  facing towards the screen  8  is an inclined surface when the middle frame fixing member  2  is in a closed position. The support member  7  guides the screen  8  to a bent shape, and the support member  7  provides an appropriate placement space for a bent position of the screen  8 . 
     As shown in  FIGS.  14  to  17   ,  FIG.  23    and  FIG.  24   , in some embodiments, a rib plate  72  is arranged at a side of the support member  7  adjacent to the middle frame fixing member  2 , and the rib plate  72  extends in the first direction. The rib plate  72  includes an inclined sliding groove  721 , and the inclined sliding groove  721  is inclined along a direction away from the first transmission assembly and towards a direction away from the support member  7  in the first direction. The connection segment  532  includes a groove shaft  533 , and the groove shaft  533  is slidably fitted in the inclined sliding groove  721 . 
     Thus, the groove shaft  533  may drive the support member  7  to rotate relative to the middle frame fixing member  2  when sliding in the inclined sliding groove  721 . As a result, it is ensured that the surface of the support member  7  facing towards the screen  8  is parallel or substantially parallel to the screen  8  when the middle frame fixing member  2  is in the flattened state, and the support member  7  guides the screen  8  to the bent shape and provides the appropriate placement space for the bent position of the screen  8  when the middle frame fixing member  2  is in the closed state. 
     As shown in  FIGS.  19  to  21   , in some embodiments, the coupling device  100  further includes a locking assembly  6  for locking the middle frame fixing member  2 . The locking assembly  6  is slidably coupled to the second transmission assembly  4  along the first direction. The second transmission assembly  4  at least includes a first side wall  4131  and a second side wall  4132 . The locking assembly  6  locks the middle frame fixing member  2  in a first position when the locking assembly  6  abuts against the first side wall  4131  of the second transmission assembly  4 . The locking assembly  6  locks the middle frame fixing member  2  in a second position when the locking assembly  6  abuts against the second side wall  4132  of the second transmission assembly  4 . 
     It may be understood that the middle frame fixing member  2  is rotatable between the first position and the second position, and the locking assembly  6  may lock the middle frame fixing member  2  in the first position or the second position. In some embodiments, the locking assembly  6  includes a first locking sub-assembly  61  and a second locking sub-assembly  62 . The first locking sub-assembly  61  is slidably coupled to the first shaft sub-sleeve  421  along the first direction, and the first locking sub-assembly  61  corresponds to the first synchronization sub-member  411 . The second locking sub-assembly  62  is slidably coupled to the second shaft sub-sleeve  422  along the first direction, and the second locking sub-assembly  62  corresponds to the second synchronization sub-member  412 . 
     The locking assembly  6  includes a first stop member  63  and a second stop member  64 . The first stop member  63  is slidably arranged on the shaft sleeve  42  of the second transmission assembly  4  along the first direction, the second stop member  64  is slidably arranged on the shaft sleeve  42  of the second transmission assembly  4  along the first direction, and the first stop member  63  or the second stop member  64  abuts against the synchronization member  41  of the second transmission assembly  4 . 
     The locking assembly  6  locks the middle frame fixing member  2  in the first position when the first stop member  63  or the second stop member  64  abuts against the first side wall  4131  of the second transmission assembly  4 . The locking assembly  6  locks the middle frame fixing member  2  in the second position when the first stop member  63  or the second stop member  64  abuts against the second side wall  4132  of the second transmission assembly  4 . 
     As shown in  FIG.  7   , specifically, the first stop member  63  includes a first stop portion  631  and a first accommodating portion  632  coupled to each other. The shaft sleeve  42  of the second transmission assembly  4  includes a second accommodating portion  426  arranged along the first direction, the first stop portion  631  is arranged at a first end of the second accommodating portion  426 , and the first accommodating portion  632  is located in the second accommodating portion  426 . The second stop member  64  includes a second stop portion  641  and a third sliding portion  642  coupled to each other. The second stop portion  641  is arranged at a second end of the second accommodating portion  426 , and the third sliding portion  642  is slidably fitted in the first accommodating portion  632 . It may be understood that the first stop portion  631  and the second stop portion  641  are arranged at two ends of the shaft sleeve  42  correspondingly and may slide relative to each other in the first direction. 
     The locking assembly  6  further includes an elastic portion  65 , and the elastic portion  65  is preferably a spring. The elastic portion  65  is located in the second accommodating portion  426  of the shaft sleeve  42  and fitted over an outer side of the first accommodating portion  632 . A first end of the elastic portion  65  abuts against the first stop portion  631  and a second end of the elastic portion  65  abuts against the second stop portion  641 . 
     The first sliding portion  413  has the first side wall  4131  and the second side wall  4132 , and an extension surface of the first side wall  4131  is perpendicular to an extension surface of the second side wall  4132 . In the first position, the first side wall  4131  abuts against the first stop portion  631  or the second stop portion  641 ; and in the second position, the second side wall  4132  abuts against the first stop portion  631  or the second stop portion  641 . Thus, the first side wall  4131  abuts against the first stop portion  631  or the second stop portion  641  in a face-to-face contact manner when the middle frame fixing member  2  is in the first position, so that positions of the first synchronization sub-member  411  and the second synchronization sub-member  412  are relatively stable. The second side wall  4132  abuts against the first stop portion  631  or the second stop portion  641  in a face-to-face contact manner when the middle frame fixing member  2  is in the second position, so that positions of the first synchronization sub-member  411  and the second synchronization sub-member  412  are relatively stable. 
     It should be noted that a compression amount of the elastic portion  65  is small when the first side wall  4131  or the second side wall  4132  abuts against the first stop portion  631  or the second stop portion  641 . Under an elastic action of the elastic portion  65 , the first transmission member  31  may not rotate and hence can realize a locking function. Only under an action of an external force, the first transmission member  31  may rotate. When a corner between the first side wall  4131  and the second side wall  4132  abuts against the first stop portion  631  or the second stop portion  641 , the compression amount of the elastic portion  65  is larger, in which case the first transmission member  31  cannot keep locked, and the elastic portion  65  pushes the first transmission member to rotate by the first side wall  4131  or the second side wall  4132  until the first transmission member rotates to the first position or the second position. Thus, users may feel a sense of damping when rotating the middle frame fixing member  2 . 
     In some embodiments, the middle frame fixing member  2  includes a middle frame fixing member body  21 , a fourth connection portion  22 , and a fifth connection portion  23 . The middle frame fixing member body  21  is configured to couple the support member  7 . The fourth connection portion  22  and the fifth connection portion  23  are arranged at a side of the middle frame fixing member body  21  adjacent to the third transmission assembly  5 , and the fifth connection portion  23  and the fourth connection portion  22  are spaced apart in the second direction. 
     The fourth connection portion  22  includes a sliding groove extending in the second direction, and the second end of the third transmission assembly  5  is slidably fitted in the sliding groove of the fourth connection portion  22 . The fifth connection portion  23  includes a sliding groove extending in the first direction, and the third end of the third transmission assembly  5  is slidably fitted in the sliding groove of the fifth connection portion  23 . 
     It should be noted that two fourth connection portions  22  are arranged at two sides of the fifth connection portion  23 , and two fifth connection portions  23  are coupled to the second end of the first swing sub-arm  511  and the second end of the second swing sub-arm  512  correspondingly. 
     In some embodiments, the coupling device  100  further includes a shaft cover  1 , the first transmission assembly  3  is hinged to the shaft cover  1 , and the first transmission assembly  3  and at least part of the second transmission assembly  4  are arranged in the shaft cover  1 . 
     In some embodiments, two middle frame fixing members  2  and two support members  7  are arranged at two sides of the shaft cover  1  in the first direction. Moreover, according to the number of middle frame fixing members  2 , some structures of the first transmission assembly  3 , the second transmission assembly  4  and the third transmission assembly  5  are symmetrical, such as the first transmission member  31 , the synchronization member  41  and the swing arm  51 ; and some other structures are provided in a singular form, such as the second transmission member  32 . That is, two symmetrical first transmission members  31  are rotatably coupled to one second transmission member  32 . 
     As shown in  FIG.  1   , the present disclosure further proposes a terminal equipment  200 , and the terminal equipment  200  includes a coupling device  100  according to any of the above embodiments. 
     In the description of the present disclosure, it shall be understood that terms such as “central,” “longitudinal,” “transverse,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial” and “circumferential” should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are only for convenience of description and do not indicate or imply that the device or element referred to must have a particular orientation, or be constructed and operated in a particular orientation. Thus, these terms shall not be construed as limitation on the present disclosure. 
     In addition, terms such as “first” and “second” are merely used for descriptive purposes and cannot be understood as indicating or implying relative importance or the number of technical features indicated. Thus, the features defined with “first” and “second” may explicitly or implicitly include at least one of the features. In the description of the present disclosure, unless otherwise specifically defined, “a plurality of” means at least two, such as two, three, etc. 
     In the present disclosure, unless otherwise explicitly specified and defined, the terms “mounted,” “interconnected,” “connected,” “fixed” and the like are used broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections or intercommunication; may also be direct connections or indirect connections via intervening structures; may also be inner communications or interactions of two elements, which can be understood by those skilled in the art according to specific situations, unless otherwise explicitly specified. 
     In the present disclosure, unless otherwise explicitly specified and defined, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature “below,” “under,” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below,” “under,” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature. 
     In the present disclosure, terms such as “an embodiment,” “some embodiments,” “an example,” “a specific example,” or “some examples,” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of these terms in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and unite different embodiments or examples or features of the different embodiments or examples described in this specification. 
     Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and shall not be understood as limitation to the present disclosure, and changes, modifications, alternatives and variations can be made in the above embodiments within the scope of the present disclosure by those skilled in the art.