Patent Publication Number: US-11641968-B1

Title: Rotatable electric mounting base and artificial tree using electric mounting base

Description:
TECHNICAL FIELD 
     The present disclosure relates to the technical field of artificial trees, and in particular, to a rotatable electric mounting base and an artificial tree applying the electric mounting base. 
     BACKGROUND 
     During Christmas, in order to foil festive atmosphere, performing festive decorations by using Christmas trees (artificial trees) has already become a necessary matter for Christmas. In order to improve the decorativeness of the Christmas trees, light strings are often hung on the Christmas trees, and the light strings have also become necessary decorations for Christmas. 
     For a Christmas tree product that needs to be rotated, in order to avoid the winding of connecting wires, a conductive joint device that can realize rotation and can ensure electrical conduction needs to be mounted at a trunk position of a Christmas tree. 
     The U.S. invention patent application Ser. No. 17/078,122 is entitled a rapid conductive joint device for a Christmas tree, which includes an upper joint component and a lower joint component matched with the upper joint component. The upper joint component includes an upper joint main body. The lower joint component includes a lower joint main body that is connected to the upper joint main body in a sleeving mode for rotating circumferentially at 360°. The upper joint main body and the lower joint main body are respectively plastic insulating pieces. The upper joint main body is provided with an upper joint conductive piece. The upper joint conductive piece includes an annular contact part. The lower joint main body is provided with a lower joint conductive piece that is in contact with a circumferential surface of the annular contact part of the upper joint conductive piece. The lower joint conductive piece is provided with an elastic contact part that is in a curved shape and is protruded toward the annular contact part side of the corresponding upper joint conductive piece. 
     For the abovementioned rapid conductive joint device for a Christmas tree, the contact and electrical conduction of conductive pieces are realized through an elastic piece structure. In the case of deformation, the elastic piece structure will lead to unstable electrical conduction, that is, the elastic piece structure has the defect of poor stability and reliability. 
     SUMMARY 
     An objective of the present disclosure is to provide a rotatable electric mounting base for the deficiencies of the prior art. The rotatable electric mounting base has a novel structural design, good stability and reliability, and convenience in mounting and connecting. 
     Another objective of the present disclosure is to provide an artificial tree. The artificial tree has a novel structural design, good stability and reliability, and convenience in mounting and connecting. 
     To achieve the abovementioned objective, the present disclosure is implemented by the following technical solutions. 
     A rotatable electric mounting base includes a base main body and a mounting shaft arranged in the vertical direction. A main body mounting hole which completely penetrates up and down is formed in the central position of the base main body. A lower end of the mounting shaft is inserted into the main body mounting hole of the base main body. The base main body is provided with a driving motor. The driving motor is connected to the mounting shaft and drives the same. 
     An electric device is mounted on the periphery of the mounting shaft in a sleeving mode. The electric device includes an upper joint component and a lower joint component that is located on a lower end side of the upper joint component and is matched with the upper joint component. The upper joint component includes an upper joint main body mounted on the periphery of the mounting shaft in a sleeving mode. The lower joint component includes a lower joint main body that is connected to a lower end of the upper joint main body in a sleeving mode for rotating circumferentially at 360° and is mounted on the periphery of the mounting shaft in a sleeving mode. The lower joint main body is buckled and fastened to the base main body. The upper joint main body and the lower joint main body are respectively plastic insulating pieces. 
     The upper joint main body is provided with an upper joint connecting wire and an upper electric connecting piece that is in an annular shape and is arranged horizontally. The upper joint connecting wire is electrically connected to the upper electric connecting piece. The lower joint main body is provided with a lower joint connecting wire and a lower electric connecting piece that is in an annular shape and is arranged horizontally. The lower electric connecting piece is electrically connected to the lower joint connecting wire. 
     The upper joint component is provided with a conductive component at the lower end side of the upper electric connecting piece. The conductive component includes a metal conductive spring and a metal conductive pin located on the lower end side of the metal conductive spring. The lower end of the metal conductive spring is pressed against the upper end of the metal conductive pin. The upper end of the metal conductive spring is pressed against and is electrically conducted with the upper electric connecting piece. The lower end of the metal conductive pin is in contact with the lower electric connecting piece and is electrically conducted with the lower electric connecting piece. 
     The upper electric connecting piece is an upper PCB that is in an annular shape and is arranged horizontally. An upper inner conductive layer and an upper outer conductive layer which are respectively in annular shapes are arranged on a lower surface of the upper PCB. The upper inner conductive layer and the upper outer conductive layer are arranged at an interval. The upper joint connecting wire is electrically connected to each of the upper inner conductive layer and the upper outer conductive layer. 
     The lower electric connecting piece is a lower PCB that is in an annular shape and is arranged horizontally. A lower inner conductive layer and a lower outer conductive layer which are respectively in annular shapes are arranged on an upper surface of the lower PCB. The lower inner conductive layer and the lower outer conductive layer are arranged at an interval. The lower joint connecting wire is electrically connected to each of the lower inner conductive layer and the lower outer conductive layer. The upper inner conductive layer and the lower inner conductive layer are aligned in the vertical direction. The upper outer conductive layer and the lower outer conductive layer are aligned in the vertical direction. 
     The conductive component includes an inner conductive component and an outer conductive component. The inner conductive component and the outer conductive component respectively include a metal conductive spring and a metal conductive pin located on the lower end side of the metal conductive spring. The lower end of each metal conductive spring is pressed against the upper end of the corresponding metal conductive pin. The upper end of the metal conductive spring of the inner conductive component is pressed against the lower inner conductive layer. The lower end of the metal conductive pin of the inner conductive component is in contact with the lower inner conductive layer. The upper end of the metal conductive spring of the outer conductive component is pressed against the upper outer conductive layer. The lower end of the metal conductive pin of the outer conductive component is in contact with the lower outer conductive layer. 
     An upper bearing and a lower bearing located on a lower end side of the upper bearing are mounted at the lower end of the mounting shaft in a sleeving mode. A main body upper shoulder and a main body lower shoulder located on a lower end side of the main body upper shoulder are arranged on an e wall of the main body mounting hole. The upper bearing is pressed against and limited at the main body upper shoulder. The lower bearing is pressed against and limited at the main body lower shoulder. 
     The driving motor is screwed and fastened to the lower end of the base main body. A power output shaft of the driving motor is connected to the lower end of the mounting shaft and drives the same. 
     A driving piece is welded at the lower end of the mounting shaft. A D-shaped hole is formed in the central position of the driving piece. A flat part consistent with the shape of the D-shaped hole is arranged at the upper end of a power output shaft of the driving motor. The flat part of the power output shaft of the driving motor is inserted into the D-shaped hole of the driving piece. 
     The upper inner conductive layer and the upper outer conductive layer are respectively metal conductive layers arranged on the lower surface of the upper PCB. 
     The lower inner conductive layer and the lower outer conductive layer are respectively metal conductive layers arranged on the upper surface of the lower PCB. 
     The upper joint main body is provided with component mounting holes corresponding to the inner conductive component and the outer conductive component respectively. The inner conductive component and the outer conductive component are respectively inserted into the component mounting holes. 
     A main body limiting shoulder is formed on an inner wall of each component mounting hole. Each metal conductive pin is provided with a conductive pin limiting shoulder. The conductive pin limiting shoulder of each metal conductive pin is located on an upper end side of the corresponding main body limiting shoulder. 
     An upper joint cover body mounted on the periphery of the mounting shaft in a sleeving mode is screwed and fastened to the upper joint main body. The upper PCB is clamped and fixed between the upper joint cover body and the upper joint main body. 
     The lower joint main body is buckled with a fixing retaining ring located at an upper end side of the lower PCB. The fixing retaining ring is in an annular shape and is mounted on the periphery of the mounting shaft in a sleeving mode. The lower PCB is clamped and fastened between the fixing retaining ring and the lower joint main body. 
     An artificial tree includes an artificial tree main body, and a decorative light string mounted on the artificial tree main body. The decorative light string is provided with a light string connecting wire. The artificial tree main body is provided with a trunk part. 
     The artificial tree further includes the abovementioned rotatable electric mounting base. The upper joint connecting wire and the light string connecting wire are connected through a butt joint and realize electrical conduction. The trunk part of the artificial tree main body is connected to the upper end of the mounting shaft. 
     An insertion hole with an upward opening is formed in the core of the mounting shaft. The trunk part of the artificial tree main body is inserted into the insertion hole of the mounting shaft. 
     The present disclosure has the beneficial effects that: the rotatable electric mounting base described in the present disclosure includes a base main body and a mounting shaft arranged in the vertical direction. A main body mounting hole which completely penetrates up and down is formed in the central position of the base main body. The lower end of the mounting shaft is inserted into the main body mounting hole of the base main body. The base main body is provided with a driving motor. The driving motor is connected to the mounting shaft and drives the same. An electric device is mounted on the periphery of the mounting shaft in a sleeving mode. The electric device includes an upper joint component and a lower joint component that is located on a lower end side of the upper joint component and is matched with the upper joint component. The upper joint component includes an upper joint main body mounted on the periphery of the mounting shaft in a sleeving mode. The lower joint component includes a lower joint main body that is connected to a lower end of the upper joint main body in a sleeving mode for rotating circumferentially at 360° and is mounted on the periphery of the mounting shaft in a sleeving mode. The lower joint main body is buckled and fastened to the base main body. The upper joint main body and the lower joint main body are respectively plastic insulating pieces. The upper joint main body is provided with an upper joint connecting wire and an upper electric connecting piece that is in an annular shape and is arranged horizontally. The upper joint connecting wire is electrically connected to the upper electric connecting piece. The lower joint main body is provided with a lower joint connecting wire and a lower electric connecting piece that is in an annular shape and is arranged horizontally. The lower electric connecting piece is electrically connected to the lower joint connecting wire. The upper joint component is provided with a conductive component at the lower end side of the upper electric connecting piece. The conductive component includes a metal conductive spring and a metal conductive pin located on the lower end side of the metal conductive spring. The lower end of the metal conductive spring is pressed against the upper end of the metal conductive pin. The upper end of the metal conductive spring is pressed against and is electrically conducted with the upper electric connecting piece. The lower end of the metal conductive pin is in contact with the lower electric connecting piece and is electrically conducted with the lower electric connecting piece. Through the abovementioned structural design, the rotatable electric mounting base has the advantages of novel structural design, good stability and reliability, and convenience in mounting and connecting. 
     The present disclosure has another beneficial effect that: the artificial tree described in the present disclosure includes an artificial tree main body, and a decorative light string mounted on the artificial tree main body. The decorative light string is provided with a light siring connecting wire. The artificial tree main body is provided with a trunk part. The artificial tree further includes the abovementioned rotatable electric mounting base. The upper joint connecting wire and the light string connecting wire are connected through a butt joint and realize electrical conduction. The trunk part of the artificial tree main body is connected to the upper end of the mounting shaft. Through the abovementioned structural design, the artificial tree of the present disclosure has the advantages of novel structural design, good stability and reliability, and convenience in mounting and connecting. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present disclosure will be further described below by using accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present disclosure. 
         FIG.  1    is a schematic structural diagram of a rotatable electric mounting base of the present disclosure. 
         FIG.  2    is a schematic exploded diagram of the rotatable electric mounting base of the present disclosure. 
         FIG.  3    is a schematic cross-sectional view of the rotatable electric mounting base of the present disclosure. 
         FIG.  4    is a schematic structural diagram of an electric device of the present disclosure. 
         FIG.  5    is a schematic cross-sectional view of the electric device of the present disclosure. 
         FIG.  6    is a schematic exploded diagram of the electric device of the present disclosure. 
         FIG.  7    is a schematic exploded diagram of the electric device in another perspective of the present disclosure. 
         FIG.  8    is a schematic structural diagram of an artificial tree of the present disclosure. 
         FIG.  9    is a schematic exploded diagram of the artificial tree of the present disclosure. 
         FIG.  10    is a partial schematic structural diagram of the artificial tree of the present disclosure. 
     
    
    
       FIG.  1    to  FIG.  10    includes: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 1-base main body 
                 11-main body mounting hole 
               
               
                 121-main body upper shoulder  
                 122-main body lower shoulder 
               
               
                 2-mounting shaft 
                 21-insertion hole 
               
               
                 3-electric device  
                 4-upper joint component 
               
               
                 41-upper joint main body 
                 411-component mounting hole 
               
               
                 4111-main body limiting shoulder 
                 42-upper PCB 
               
               
                 421-upper inner conductive layer  
                 422-upper outer conductive layer 
               
               
                 43-inner conductive component 
                 44-outer conductive component 
               
               
                 451-metal conductive spring  
                 452-metal conductive pin 
               
               
                 4521-conductive pin limiting  
                 46-upper joint cover body 
               
               
                 shoulder 
                   
               
               
                 47-upper joint connecting wire 
                 5-lower joint component 
               
               
                 51-lower joint main body 
                 52-lower PCB 
               
               
                 521-lower inner conductive layer  
                 522-lower outer conductive layer 
               
               
                 53-fixing retaining ring  
                 54-lower joint connecting wire 
               
               
                 61-upper bearing  
                 62-lower bearing 
               
               
                 71-driving motor 
                 711-flat part 
               
               
                 72-driving piece  
                 721-D-shaped hole 
               
               
                 8-artificial tree main body 
                 81-trunk part 
               
               
                 9-decorative light string 
                 91-string light connecting wire 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION 
     The present disclosure will be described below in combination with specific implementation modes. 
     As shown in  FIG.  1    to  FIG.  7   , a rotatable electric mounting base includes a base main body  1  and a mounting shaft  2  arranged in the vertical direction. A main body mounting hole  11  which completely penetrates up and down is formed in the central position of the base main body  1 . A lower end of the mounting shaft  2  is inserted into the main body mounting hole  11  of the base main body  1 . The base main body  1  is provided with a driving motor  71 . The driving motor  71  is connected to the mounting shaft  2  and drives the same. The driving motor  71  is used for driving the mounting shaft  2  to rotate. 
     An electric device  3  is mounted on the periphery of the mounting shaft  2  in a sleeving mode. The electric device  3  includes an upper joint component  4  and a lower joint component  5  that is located on a lower end side of the upper joint component  4  and is matched with the upper joint component  4 . The upper joint component  4  includes an upper joint main body  41  mounted on the periphery of the mounting shaft  2  in a sleeving mode. The lower joint component  5  includes a lower joint main body  51  that is connected to a lower end of the upper joint main body  41  in a sleeving mode for circumferentially rotating at 360° and is mounted on the periphery of the mounting shaft  2  in a sleeving mode. The lower joint main body  51  is buckled and fastened to the base main body  1 , The upper joint main body  41  and the lower joint main body  51  are respectively plastic insulating pieces. 
     Further, the upper joint main body  41  is provided with an upper joint connecting wire  47  and an upper electric connecting piece that is in an annular shape and is arranged horizontally. The upper joint connecting wire  47  is electrically connected to the upper electric connecting piece. The lower joint main body  51  is provided with a lower joint connecting wire  54  and a lower electric connecting piece that is in an annular shape and is arranged horizontally. The lower electric connecting piece is electrically connected to the lower joint connecting wire  54 . 
     Furthermore, the upper joint component  4  is provided with a conductive component at the lower end side of the upper electric connecting piece. The conductive component includes a metal conductive spring  451  and a metal conductive pin  452  located on the lower end side of the metal conductive spring  451 . The lower end of the metal conductive spring  451  is pressed against the upper end of the metal conductive pin  452 . The upper end of the metal conductive spring  451  is pressed against and is electrically conducted with the upper electric connecting piece. The lower end of the metal conductive pin  452  is in contact with the lower electric connecting piece and is electrically conducted with the lower electric connecting piece. 
     Specifically: the upper electric connecting piece is an upper PCB  42  that is in an annular shape and is arranged horizontally. An upper inner conductive layer  421  and an upper outer conductive layer  422  which are respectively in annular shapes are arranged on a lower surface of the upper PCB  42 . The upper inner conductive layer  421  and the upper outer conductive layer  422  are arranged at an interval. The upper joint connecting wire  47  is electrically connected to each of the upper inner conductive layer  421  and the upper outer conductive layer  422 , The lower electric connecting piece is a lower PCB  52  that is in an annular shape and is arranged horizontally. A lower inner conductive layer  521  and a lower outer conductive layer  522  which are respectively in annular shapes are arranged on an upper surface of the lower PCB  52 , The lower inner conductive layer  521  and the lower outer conductive layer  522  are arranged at an interval. The lower joint connecting wire  54  is electrically connected to each of the lower inner conductive layer  521  and the lower outer conductive layer  522 . The upper inner conductive layer  421  and the lower inner conductive layer  521  are aligned in the vertical direction. The upper outer conductive layer  422  and the lower outer conductive layer  522  are aligned in the vertical direction. The conductive component includes an inner conductive component  43  and an outer conductive component  44 . The inner conductive component  43  and the outer conductive component  44  respectively include a metal conductive spring  451  and a metal conductive pin  452  located on the lower end side of the metal conductive spring  451 . The lower end of each metal conductive spring  451  is pressed against the upper end of the corresponding metal conductive pin  452 . The upper end of the metal conductive spring  451  of the inner conductive component  43  is pressed against the lower inner conductive layer  421 . The lower end of the metal conductive pin  452  of the inner conductive component  43  is in contact with the lower inner conductive layer  521 . The upper end of the metal conductive spring  451  of the outer conductive component  44  is pressed against the upper outer conductive layer  422 . The lower end of the metal conductive pin  452  of the outer conductive component  44  is in contact with the lower outer conductive layer  522 . 
     It is to be noted that specific structures of the abovementioned upper electric connecting piece and the lower electric connecting piece do not constitute a limitation to the present disclosure, that is, the upper electric connecting piece and the lower electric connecting piece of the present disclosure may also in other structural forms. 
     During using the rotatable electric mounting base of the present disclosure, the upper end of the mounting shaft  2  is used for mounting the artificial tree. The decorative light string  9  on the artificial tree is connected to the upper joint connecting wire  47  through a corresponding light string connecting wire  91 . The mounting shaft  2  rotates under the driving action of the driving motor  71 . The electric device  3  is mounted on the periphery of the mounting shaft  2  in a sleeving mode. The lower joint main body  51  is screwed on the base main body  1 . The lower joint main body  51  is connected to the lower end of the upper joint main body  41  in a sleeving mode for circumferentially rotating at 360°. When the artificial tree needs to be rotated, the upper joint main body  41  rotates along with the artificial tree, which can effectively prevent the upper joint connecting wire  47  and the light string connecting wire  91  from winding. 
     For the electric device  3  of the present disclosure, during realizing electrical connection between the upper joint component  4  and the lower joint component  5 , the upper joint component  4  is located above the lower joint component  5 , the upper inner conductive layer  421  of the upper PCB  42  is electrically conducted with the lower inner conductive layer  521  of the lower PCB  52  through an inner conductive component  43 , and the upper outer conductive layer  422  of the upper PCB  42  is electrically conducted with the lower outer conductive layer  522  of the upper PCB  42  through an outer conductive component  44 , Since various metal conductive pins  452  are respectively pressed downwards through corresponding metal conductive springs  451 , during rotating the upper joint component  4  relative to the lower joint component  5  under the action of an elastic force of the metal conductive spring  451 , the metal conductive pin  452  of the inner conductive component  43  is kept in contact with and pressing against the lower inner conductive layer  521  of the lower PCB  52 , and the metal conductive pin  452  of the outer conductive component  44  is kept in contact with and pressing against the lower outer conductive layer  522  of the lower PCB  52 . 
     It is to be emphasized that, compared with the prior art, the electric device  3  of the present disclosure does not have unstable electrical conduction caused by the deformation of a contact elastic piece. 
     In addition, during mounting the artificial tree on the rotatable electric mounting base of the present disclosure, only the trunk part  81  of the artificial tree needs to be mounted on an upper end of the mounting shaft  2 , and the light string connecting wire  91  of the decorative light string  9  needs to be connected to the upper joint connecting wire  47 , so the mounting and connecting are convenient. 
     It can be known from the abovementioned conditions that, through the abovementioned structural design, the present disclosure has the advantages of novel structural design, good stability and reliability, and convenience in mounting and connecting. 
     As a preferred implementation mode, as shown in  FIG.  2    and  FIG.  3   , the lower end of the mounting shaft  2  of the present disclosure may be mounted in the main body mounting hole  11  of the base main body  1  in the following modes, specifically: an upper bearing  61  and a lower bearing  62  located on a lower end side of the upper bearing  61  are mounted at the lower end of the mounting shaft  2  in a sleeving mode; a main body upper shoulder  121  and a main body lower shoulder  122  located on a lower end side of the main body upper shoulder  121  are arranged on an inner wall of the main body mounting hole  11 ; the upper bearing  61  is pressed against and limited at the main body upper shoulder  121 ; and the lower bearing  62  is pressed against and limited at the main body lower shoulder  122 . 
     As a preferred implementation mode, as shown in  FIG.  2    and  FIG.  3   , the driving motor  71  is screwed and fastened to the lower end of the base main body  1 . A power output shaft of the driving motor  71  is connected to the lower end of the mounting shaft  2  and drives the same. 
     Specifically, the driving motor  71  of the present disclosure may be connected to the lower end of the mounting shaft ( 2 ) and drives the same in the following modes, specifically: a driving piece  72  is welded at the lower end of the mounting shaft  2 ; a D-shaped hole  721  is formed in the central position of the driving piece  72 ; a flat part  711  consistent with the shape of the D-shaped hole  721  is arranged at the upper end of a power output shaft of the driving motor  71 ; and the flat part  711  of the power output shaft of the driving motor  71  is inserted into the D-shaped hole  721  of the driving piece  72 . Of course, the abovementioned D-shaped hole  721  does not construe a limitation to the present disclosure. Hole structures in other shapes may also be formed in the central position of the driving piece  72 . The shape of the upper end of the power output shaft of the driving motor  71  is consistent with those of the abovementioned hole structures. 
     For an artificial tree product that rotates automatically, during working, the driving motor  71  drives the mounting shaft  2  to rotate through the driving piece  72  after being powered on, the rotating mounting shaft  2  drives the artificial tree mounted at the upper end of the mounting shaft  2  to rotate, so that the artificial tree rotates automatically. 
     As a preferred implementation mode, as shown in  FIG.  6    and  FIG.  7   , the upper inner conductive layer  421  and the upper outer conductive layer  422  are respectively metal conductive layers arranged on the lower surface of the upper PCB  42 ; and similarly, the lower inner conductive layer  521  and the lower outer conductive layer  522  are respectively metal conductive layers arranged on the upper surface of the lower PCB  52 . 
     As a preferred implementation mode, as shown in  FIG.  5   , the inner conductive component  43  and the outer conductive component  44  of the present disclosure may be mounted on the upper joint main body  41  in the following modes, specifically: the upper joint main body  41  is provided with component mounting holes  411  corresponding to the inner conductive component  43  and the outer conductive component  44  respectively; the inner conductive component  43  and the outer conductive component  44  are respectively embedded into the corresponding component mounting holes  411 ; a main body limiting shoulder  4111  is formed on an inner wall of each component mounting hole  411 ; each metal conductive pin  452  is provided with a conductive pin limiting shoulder  4521 ; and the conductive pin limiting shoulder  4521  of each metal conductive pin  452  is located on an upper end side of the corresponding main body limiting shoulder  4111 . 
     For the inner conductive component  43  and the outer conductive component  44 , the conductive pin limiting shoulder  4521  of each metal conductive pin  452  is located on the upper end side of the corresponding main body limiting shoulder  4111 , so that when the metal conductive pin  452  moves to a limit position downwards relative to the upper joint main body  41 , the conductive pin limiting shoulder  4521  of each metal conductive pin  452  is pressed against and limited at the main body limiting shoulder  4111  of the upper joint main body  41 . That is, the metal conductive pin  452  is limited by matching the main body limiting shoulder  4111  and the conductive pin limiting shoulder  4521 , so that the metal conductive pin  452  is prevented from withdrawing from the corresponding component mounting hole  411 . 
     As a preferred implementation mode, as shown in  FIG.  4    to  FIG.  7   , the upper PCB  42  of the present disclosure may be mounted on the upper joint main body  41  in the following modes, specifically: an upper joint cover body  46  mounted on the periphery of the mounting shaft  2  in a sleeving mode is screwed and fastened to the upper joint main body  41 ; and the upper PCB  42  is clamped and fixed between the upper joint cover body  46  and the upper joint main body  41 . 
     Furthermore, the lower PCB  52  of the present disclosure may be mounted on the lower joint main body  51  in the following modes, specifically: the lower joint main body  51  is buckled with a fixing retaining ring  53  located at an upper end side of the lower PCB  52 ; the fixing retaining ring  53  is in an annular shape and is mounted on the periphery of the mounting shaft  2  in a sleeving mode; and the lower PCB  52  is clamped and fastened between the fixing retaining ring  53  and the lower joint main body  51 . 
     As a preferred implementation mode, as shown in  FIG.  8    to  FIG.  10   , an artificial tree includes an artificial tree main body  8 , and a decorative light string  9  mounted on the artificial tree main body  8 . The decorative light string  9  is provided with a light string connecting wire  91 . The artificial tree main body  8  is provided with a trunk part  81 . 
     Further, the artificial tree further includes the abovementioned rotatable electric mounting base. The upper joint connecting wire  47  and the light string connecting wire  91  are connected through a butt joint and realize electrical conduction. The trunk part  81  of the artificial tree main body  8  is connected to the upper end of the mounting shaft  2 . 
     Furthermore, an insertion hole  21  with an upward opening is formed in the core of the mounting shaft  2 . The trunk part  81  of the artificial tree main body  8  is inserted into the insertion hole  21  of the mounting shaft  2 . 
     It is to be explained that, during mounting and connecting the artificial tree of the present disclosure, the trunk part  81  of the artificial tree is aligned with and inserted into the insertion hole  21  of the mounting shaft  2 , and then the light string connecting wire  91  of the decorative light string  9  is connected to the upper joint connecting wire  47 . The mounting and connecting are convenient. 
     In addition, the electric mounting base has the advantages of good stability and reliability, that is, the artificial tree also has the advantages of good stability and reliability. 
     The above content is only preferred embodiments of the present disclosure. For those of ordinary skill in the art, according to the idea of the present disclosure, there will be changes in the specific implementation mode and application scope, and the contents of this specification should not be construed as a limitation to the present disclosure.