Abstract:
A top support structure of a tent frame includes a top pivot holder ( 1 ), to which a plurality of support poles ( 10 ) are pivotally coupled. An elastic member ( 9 ) is provided between each support pole and the pivot holder. The elastic member folds and stores elasticity energy when the tent frame is folded and automatically springs the support poles when the elasticity energy is released. A control holder ( 2 ) is pivotally coupled to the bottom of the pivot holder, and the control holder has lock pieces ( 211 ) which can prop the support poles up to limit their rotation and release grooves ( 212 ) adjacent to the lock pieces which can release the limitation. On the top of pivot grooves ( 12 ) of the pivot holder are provided with position-limited devices (D) to prevent the support poles from rotating upwards.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a tent part, and more particularly to a top support structure of a tent frame. 
     2. Description of the Prior Art 
     A conventional automatic extendable tent frame comprises a top pivot holder. The pivot holder has pivot troughs for connection of support poles and elastic units which correspond in number to the support poles. When the support poles are folded downward with respect to the pivot holder, the elastic units provide elasticity. Each support pole is movably connected to the pivot holder and rotatable with relative to the pivot holder. One end of each elastic unit is connected to the support pole and another end of each elastic unit is connected to the pivot holder. It is required to apply a force to retract the support poles inward when folding the tent. When unfolding the tent, the restoring force of the elastic units will expand the support poles up relative to the pivot holder, providing an automatic extendable function. This shows that the top support frame of this tent depends on the elasticity of the elastic units. If the top of the tent is applied with a force, the support poles are easy to be folded downward. Thus, the support strength of the support poles is not enough. The outer support poles may be raised relative to the pivot holder subject to the elastic action of the elastic units. When the tent is influenced by wind force or external force, the tent frame is easy to shake. The tent lacks support stability. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a top support structure to strengthen a tent frame, preventing support poles from folding downward when the top of the tent is applied with a force. 
     A further object of the present invention is to provide a top support structure to ensure the stability of the tent frame, with a better raised angle of the support poles. 
     In order to achieve the aforesaid objects, the solution of the present invention is to provide a top support structure of a tent frame. 
     The top support structure comprises a top pivot holder. The pivot holder is pivotally connected with support poles. An elastic member is provided between the pivot holder and each of the support poles. The elastic member is bent to store an elastic energy when the tent frame is folded. The elastic member will automatically spring a corresponding support pole when the elastic energy is released. Wherein a control holder is provided under the pivot holder and pivotally connected to the pivot holder. The control holder comprising lock pieces to hold against the support poles and to limit rotation of the support poles and release troughs each disposed between two of the adjacent lock pieces. 
     The pivot holder has pivot troughs to receive the support poles therein. 
     A position-limit device is provided on each of the pivot troughs to prevent the support poles from moving upward. 
     Each of the support poles is pivotally connected in a corresponding pivot trough through a connection head. 
     A metallic sleeve is provided between the connection head and a connection part of each of the support poles to enhance connection of the support pole and the connection head. 
     The connection head has a neck at a rear part thereof. The neck is inserted in a corresponding support pole. A metallic rod is provided in the neck to enhance the neck. 
     The control holder has an arc guide slot. A guide post is connected with the pivot holder and inserted through the guide slot. The central angle of the guide slot is equal to the central angle between two adjacent release troughs. 
     The control holder comprises a handle disposed under the control holder. 
     A metallic plate is provided in or on the control holder. 
     The position-limit device includes a positioning hole and a fixing hole disposed on two side walls of each of the pivot troughs of the pivot holder. A rotation shaft is inserted through a shaft hole of the support pole and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole to block the support pole from moving upward. 
     The position-limit device includes a positioning hole and a fixing hole disposed on two side walls of each of the pivot troughs of the pivot holder. A rotation shaft is inserted through a shaft hole of the connection head and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole to block the connection head from moving upward. 
     The positioning shaft is located above an outer side of the rotation shaft. One end of the elastic member is fixed to an inner side of the pivot holder, and the other end of the elastic member is fixed to the support pole. 
     The positioning shaft is located above an outer side of the rotation shaft. One end of the elastic member is fixed to an inner side of the pivot holder, and the other end of the elastic member strides over the positioning shaft and is fixed to the connection head. 
     The position-limit device includes a crescent groove of the connection head. The crescent groove is disposed between a top end of the connection head and a shaft hole. Two side walls of each of the pivot troughs of the pivot holder have a positioning hole and a fixing hole under the positioning hole. A rotation shaft is inserted through a shaft hole of the connection head and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole and inserted through the crescent groove of the connection head to block the connection head from moving upward. 
     The position-limit device is a stop block which is integrally formed with each of the pivot troughs of the pivot holder. A corresponding support pole is located under the stop block and pivotally connected in a corresponding pivot trough. 
     The stop block has concave upper and lower surfaces. A first end of the elastic member is fixed to an inner side of the pivot trough, and a second end of the elastic member strides over the stop block and is connected to a corresponding support pole. 
     Each of the pivot troughs of the pivot holder is provided with a fixing axle to connect with one end of the elastic member. 
     Each of the support poles is provided with a connection block. The connection block has a connection axle to connect another end of the elastic member. The connection block is provided with a hook underneath the connection block. 
     A metallic sleeve is provided between the connection block and the connection head. 
     Each of the pivot troughs of the pivot holder is provided with a decoration cover to cover a corresponding support pole. 
     A front portion of the decoration cover is shaped like a hook and has a crescent groove and a shaft hole. The crescent groove and the shaft hole corresponding to a crescent groove and a shaft hole of a connection head. A rotation shaft is inserted through the shaft hole of the decoration cover and the shaft hole of the connection head to connect the decoration cover with the connection head. 
     The top support structure of a tent frame further comprises a top cover which is fixed on top of the pivot holder. 
     Accordingly, the rotatable control holder is provided under the pivot holder. The lock pieces and the release troughs of the control holder are turned to correspond to the pivot troughs of the pivot holder for the release troughs to be under the pivot troughs, such that the support poles can be turned relative to the pivot troughs (The control holder won&#39;t restrict turning of the support poles.) to fold the tent frame. The control holder is turned to achieve the aforesaid effect. This is convenient and quick way to fold the tent frame. When the tent is in an unfolded state, the lock pieces will be located under the pivot troughs. The support poles are supported on the lock pieces and can&#39;t be moved or folded downward. The tent frame is unfolded steadily. 
     Besides, the pivot holder is provided with the position-limit device to restrict the angle of the support poles to be moved upward, so the support poles are steady after the tent is unfolded. By the control holder to position the support poles, the unfolded tent frame has upper and lower positioning effects to secure the tent firmly. 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view according to a first embodiment of the present invention; 
         FIG. 2A ,  FIG. 2B  and  FIG. 2C  are a top perspective view, a bottom perspective view and a cross-sectional view of the pivot holder according to the first embodiment of the present invention; 
         FIG. 3  is a perspective view of the control holder of the present invention; 
         FIG. 4A ,  FIG. 4B  and  FIG. 4C  are a perspective view, a front view and a top view of the connection head according to the first embodiment of the present invention; 
         FIG. 4D  is a perspective view of another embodiment of the connection head of the present invention; 
         FIG. 5A ,  FIG. 5B  and  FIG. 5C  are a perspective view, a front view and a top view of the decoration cover according to the first embodiment of the present invention; 
         FIG. 6  is a perspective view according to the first embodiment of the present invention; 
         FIG. 7  is partially schematic view according to the first embodiment of the present invention; 
         FIG. 8  is a perspective view according to a second embodiment of the present invention; 
         FIG. 9  is a perspective view according to a third embodiment of the present invention; 
         FIG. 10  is a perspective view of the pivot holder according to the third embodiment of the present invention; and 
         FIG. 11  is a front view according to a fourth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 1 ,  FIG. 6  and  FIG. 7 , a top support structure of a tent frame according to a first embodiment of the present invention is connected with support poles  10  and elastic members  9 . The elastic members  9  will be bent to store elastic energy when the tent is folded. The elastic members  9  can automatically spring the support poles  10  when the elastic energy is released. 
     The top structure comprises a pivot holder  1 , a control holder  2 , four connection heads  3 , a decoration cover  4 , a rotation shaft  5 , a position-limit device D, and a top cover  7 . The position-limit device D includes a positioning shaft  6  and a crescent groove  35  of the connection head  3 . 
     The top cover  7  is coupled to the pivot holder  1 . The control holder  2  is pivotally connected to the pivot holder  1  and rotatable with respect to the pivot holder  1 . Inner ends of the four connection heads  3  are inserted through the notches  71  of the top cover  7  and pivotally connected to the pivot holder  1 , respectively. Outer ends of the four connection heads  3  are connected to the support poles  10 , respectively. 
     As shown in  FIGS. 2A ,  2 B, and  2 C, the pivot holder  1  comprises a base  11 . The base  11  has four pivot troughs  12  which are equally spaced, a pair of ribs  13  at two sides of each of the pivot troughs  12 , and spaced positioning protrusions  14  disposed under the base  11 . The pivot trough  12  is defined between the pair of ribs  13 . Each of the pair of ribs  13  is formed with a positioning hole  16  and a fixing hole  15  under the positioning hole  16 . The rotation shaft  5  is inserted through a shaft hole  33  of the connection head  3  and fixed in the fixing hole  15 . The positioning shaft  6  is fixed in the positioning hole  16 . 
     As shown in  FIG. 3 , the control holder  2  comprises a control plate  21  and a handle  22  under the control plate  21 . The control plate  21  has four lock pieces  211  to hold against the support poles  10  and to limit rotation of the support poles  10 . A release trough  212  is formed between two adjacent lock pieces  211 . Each of the lock pieces  211  has an arc guide slot  213 . The axis of the guide slot  213  is overlapped with the axis of the control holder  2 . The central angle of the guide slot  213  is equal to the central angle between two adjacent release troughs  212 . In order to enhance the strength of the control holder  2 , a metallic plate  214  may be provided in or on the control plate  21 . 
     Referring to  FIG. 1  and  FIG. 3 , the pivot holder  1  is provided with a guide post  8 . A lower end of the guide post is moveably connected in the arc guide trough  213 , so the control holder  2  under the pivot holder  1  is rotatable with respect to the holder  1 . Outer edges of the lock pieces  211  of the control holder  2  are exposed out of an outer edge of the pivot holder  1 . The spaced positioning protrusions are against a top surface of the control holder  2 , such that a space is formed between the pivot holder  1  and the control holder  2 . Due to the space, the support poles  10  are slightly oblique downward when they are in a locked state. 
     As shown in  FIGS. 4A ,  4 B, and  4 C, each of the connection heads  3  comprises a connection post  31  and a pair of connection lugs  32  at one end of the connection post  31 . The pair of connection lugs  32  has the shaft hole  33  for insertion of the rotation shaft  5 . The pair of connection lugs  32  is larger in area than the connection post  31 . The connection post  31  has an inner axial hole  34  for insertion of a corresponding support pole  10  to be secured thereat. The pair of connection lugs  3  has the crescent groove  35  for insertion of the positioning shaft  6 . The crescent groove  35  is disposed between a top end of the connection head  3  and the shaft hole  33 . The positioning shaft  6  is inserted through the positioning hole  16  and secured in the crescent groove  35  of the connection head  3  to stop the connection head  3  from moving upward. 
     As shown in  FIG. 4D , the connection head  3  has a neck  34  instead of the axial hole  34 . A metallic rod  341  is provided in the neck  34  to enhance the strength of the neck  34 . The metallic rod  341  is connected to the support pole  10 . 
     Referring to  FIGS. 5A ,  5 B,  5 C, a front portion of the decoration cover  4  is shaped like a hook and has a crescent groove  41  and a shaft hole  42 . The crescent groove  41  and the shaft hole  42  correspond to the crescent groove  35  and the shaft hole  33  of the connection head  3 . The rotation shaft  5  is inserted through the shaft hole  42  of the decoration cover  4  and the shaft hole  33  of the connection head  3  to connect the decoration cover  4  with the connection head  3 . 
     As shown in  FIG. 1 ,  FIG. 6  and  FIG. 7 , to assemble the present invention, an upper end of each support poles  10  is inserted into the axial hole  34  of the connection post  31  of the connection head  3 . In order to enhance the strength of the connection post  31 , the connection post  31  may be provided with a metallic sleeve. The connection head  3  is located in the pivot trough  12  of the pivot holder  1 . The rotation shaft  5  is inserted in the fixing holes  15  of the pair of ribs  13  of the pivot holder  1  and the shaft holes  33  of the pair of lugs  32  of the connection head  3 , so the support pole  10  is pivotally connected in the pivot trough  12  of the pivot holder  1 . Referring to the  FIG. 7 , a first end of the elastic member  9  is fixed to a fixing axle  92 , and a second end of the elastic member  9  is inserted through the pair of connection lugs  32  and connected to the support pole  10 . The support pole  10  is provided with a connection block  101 . The connection block  101  has a connection axle  91  to connect the second end of the elastic member  9 . The elastic member  9  will generate elasticity when bent. In order to prevent the connection block  101  from loosening after a period of time, a metallic sleeve  102  is provided between the connection block  101  and the connection head  3  to limit the connection block  101  and to enhance the strength of the joint of the support pole  10  and the connection head  3 . When folding the tent frame, the elastic member  9  will be bent to store elastic energy. The elastic energy will automatically spring the support pole  10  when the elastic member  9  is released. 
     To fold the tent frame, the control holder  2  is turned for the arc guide slot  213  to correspond to the guide post  8 . When the release trough  212  is aligned with the pivot trough  12 , the user can move the support poles  10  downward with respect to the pivot holder  1  to bend the elastic members  9 . To unfold the tent frame, the elastic energy is released to spring the support poles  10 , and the control holder  2  is turned for the lock pieces  211  to be located under the pivot troughs  12 , and the connection heads  3  are against the lock pieces  211 , so the support poles  10  are unfolded steadily. 
       FIG. 8  shows a second embodiment of the present invention, which is substantially similar to the first embodiment with the exceptions described hereinafter. The position-limit device D is the positioning hole  16  and the fixing hole  15  formed on two side walls of the pivot trough  12  of the pivot holder  1 . The two side walls are formed with, respectively. The support pole  10  is pivoted in the pivot trough  12  through the rotation shaft  5 . The positioning shaft  6  is located above the rotation shaft  5 . The first end of the elastic member  9  is fixed to the fixing axle  92  which is located at an inner side of the pivot trough  12 . The second end of the elastic member  9  strides over the positioning shaft  6  and is connected to the connection axle  91  of the connection block  101  of the support pole  10 . In this embodiment, the positioning shaft  6  also prevents the support pole  10  from moving upward. The support pole  10  is also connected to the pivot holder  1  through the connection head  3 . 
       FIG. 9  and  FIG. 10  show a third embodiment of the present invention, which is substantially similar to the first embodiment with the exceptions described hereinafter. The position-limit device D is a stop block  17  which is integrally formed with the pivot trough  12  of the pivot holder  1 . The stop block  17  has concave upper and lower surfaces. The support pole  10  is located under the stop block  17  and pivotally connected in the pivot trough  12 . The first end of the elastic member  9  is fixed to the fixing axle  92  which is located at an inner side of the pivot trough  12 . The second end of the elastic member  9  strides over the stop block  17  and is connected to the connection axle  91  of the connection block  101  of the support pole  10 . The stop block  17  provides a limit effect to the unfolded support pole  10 . 
     As shown in  FIG. 11 , the connection block  101  may be provided with a hook  103  underneath the connection block  101  to secure the tent cloth. 
     The feature of the present invention is that the rotatable control holder  2  is provided under the pivot holder  1 . The lock pieces  211  and the release troughs  212  of the control holder  2  are turned to correspond to the pivot troughs  12  of the pivot holder  1  for the release troughs  212  to be under the pivot troughs  12 , such that the support poles  10  can be turned relative to the pivot troughs  12  (The control holder  2  won&#39;t restrict turning of the support poles  10 ) to fold the tent frame. The control holder  2  is turned to achieve the aforesaid effect. This is convenient and quick way to fold the tent frame. When the tent is in an unfolded state, the lock pieces  211  will be located under the pivot troughs  12 . The support poles  10  are supported on the lock pieces  211  and can&#39;t be moved or folded downward. The tent frame is unfolded steadily. Besides, the pivot holder  1  is provided with the position-limit device D to restrict the angle of the support pole  10  to be moved upward, so the support poles  10  are steady after the tent is unfolded. By the control holder to position the support poles  10 , the unfolded tent frame has upper and lower positioning effects to secure the tent firmly. 
     Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.