Abstract:
A mechanism for opening and closing a tent or awning is disclosed. A plurality of poles are pivotally attached to a hub at upper engagement points. A plurality of braces are pivotally coupled to the poles at lower engagement points at one end and pivotally coupled to a base at another end. The base has a shaft slidable in the hub and the shaft houses a biasing member which generates an upward force on the shaft which is transmitted to the braces and the poles. The upward force urges the poles to pivot toward the open position when the lower engagement point is radially outward of the upper engagement point, and the upward force urges the poles to pivot toward the closed position when the lower engagement point is radially inward of the upper engagement point.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a tent or awning, and more particularly to a mechanism for opening and closing a tent or awning. 
         [0003]    2. Description of Prior Art 
         [0004]    Tents or awnings are leisure apparatuses standing outdoors. Conventional big foldable tents or awnings require more operators for operating smoothly due to the bigger volume and heavier weight. So, there are a variety of roof staying mechanisms for facilitating the pitching and closing operation as their essential aims. Over the years, tents with umbrella-type collapsible frames have been developed to accommodate the user with easy opening and closing of tents but the user also encountered problems associated with failing parts, namely, failure in the locking mechanism. 
         [0005]    So, more recently, umbrella-type tents without locking mechanisms have been developed to eliminate the concern for any potential malfunction of a locking mechanism on a tent. For example, the tent shown in U.S. Pat. No. 6,581,617 (“&#39;617 Tent”), incorporated herein by reference, does not have a locking mechanism but is nevertheless capable of remaining open and closed. Even though the &#39;617 Tent does not require a locking mechanism, it still has its disadvantages. First, substantial force is required to close the tent because the user must overcome the resistance generated by the lengthy spring  18 . Second, the tent is much bulkier due to the length of the shank part of the rib holder  14 . 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0006]    The present invention solves the problems described above while maintaining the advantages of a tent which is capable of remaining open and closed without a further locking mechanism. The present invention allows a user to open and close a tent without much effort. Further, because the mechanism is compact, the tent is more convenient to store as well as for travel purposes. 
         [0007]    In order to accomplish the above object, the present invention provides a central mechanism for opening and closing a tent or awning. The tent includes a plurality of poles each having a proximal end pivotally coupled to said central mechanism and a distal end, and movable between open and closed positions; and a plurality of braces each having a distal end pivotally coupled to the pole and a proximal end pivotally coupled to said central mechanism, and movable between open and closed positions. The central mechanism includes a base having a plurality of brace-engaging means pivotally coupled to said proximal ends of braces, respectively; a hollow shaft defined by tubular walls having upper and lower ends, said shaft extending axially upward from the base at a substantially center location of the base with the lower end of the shaft fixed to the base and the upper end of the shaft at least partially closed, the lower end of said shaft&#39;s tubular walls having cut-outs extending axially on radially opposite sides for receiving a sliding plate, said sliding plate extending radially outward and transversely through said cut-outs beyond said tubular walls for axial movement between its open and closed positions within and relative to said cut-outs; a biasing member engaging the top closure of the shaft and biasing said sliding plate downward; a hub having a central bore in which said shaft is movable axially relative to the hub, said hub having a plurality of pole-engaging means pivotally engaging said proximal ends of said poles; at least two rods, each having a top end fixed to said hub and a bottom end fixed to ends of said sliding plate, and said shaft being slidable between an open position where the biasing member is compressed and a closed position where the biasing member is less compressed, wherein a force from the biasing member in its less compressed state pushes the shaft upward relative to the hub thereby driving the braces and poles to the open position. 
         [0008]    In operation, to open the tent, the poles are pulled away from the center of the tent or awning, at which time the biasing member located between the hub and the base expands so as to push closer the base relative to the hub. The upward force exerted by the biasing member causes an outward torque force on the poles and enables the tent to remain open without an additional locking mechanism or further external force. 
         [0009]    Similarly, the tent or awning is closed when the operator exerts force on the poles downward so that all of the poles and braces move closer to the center of the tent or awning. The biasing member contracts as the base and hub move away from each other. The upward force exerted by the biasing member causes an inward torque force on the poles and enables the tent to remain closed without an additional locking mechanism or further external force. 
         [0010]    Thus, the combination of the forces generated from the biasing member and the kinetics of the poles and braces not only facilitates the opening and closing of the tent or awning but also provides support such that the tent or awning is maintained in its open and closed positions without an additional locking mechanism or external force. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a partial exploded view showing the first embodiment of the present invention. 
           [0012]      FIG. 2  is a perspective view showing the open configuration of the first embodiment of the present invention. 
           [0013]      FIG. 3  is a partial perspective view showing the closed configuration of the first embodiment of the present invention. 
           [0014]      FIG. 4  is a partial side view showing the open configuration of the second embodiment of the present invention. 
           [0015]      FIG. 5  is a partial side view showing the closed configuration of the second embodiment of the present invention. 
           [0016]      FIG. 6  is a partial side view showing the open configuration of the third embodiment of the present invention. 
           [0017]      FIG. 7  is a partial side view showing the closed configuration of the third embodiment of the present invention. 
           [0018]      FIG. 8  is a fragmentary cross-sectional view of the third embodiment of the present invention in its open position. 
           [0019]      FIG. 9  is a fragmentary cross-sectional view of the third embodiment of the present invention in its closed position, with its neutral position in phantom lines. 
           [0020]      FIG. 10  is a perspective view of a foldable tent or awning with the mechanism in its open position. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0021]    A foldable tent or awning  200  having a central roof staying mechanism  202  of the present invention is shown in  FIG. 10 . Referring to  FIG. 1 , a central roof staying mechanism  202  of in the first embodiment of the present invention shown is typically comprised of a hub  1 , a base  2 , biasing member  3 , sliding plate  4 , poles  5  and braces  6 . 
         [0022]    Said hub  1  has pole slots  11  built on the four sides on the trunk respectively, a channel  12  formed on the center, and two holes  13  built on the opposite sides of the channel  12  axially. 
         [0023]    Said base  2  has a hollow shaft  21  built on the upper portion, and brace slots  22  built respectively on the side walls of the trunk, and two opposite cut-outs  23  built on the shaft  21  from the middle portion to the bottom of the shaft  21 . The shaft  21  is fully enclosed at its top distal end. 
         [0024]    Said biasing member  3  is a bar  31  and cylinder  32  combination, with a spring or a pneumatic linear actuator placed inside of the cylinder  32  for the bar  31  to slide in and out of the cylinder  32 , and in the normal configuration, said bar  31  is extended out from the inside of the cylinder  32 . Alternatively, the bar  31  and cylinder  32  arrangement can be replaced with one or more springs  3  as shown in  FIGS. 8 and 9 . 
         [0025]    Said sliding plate  4  is a strap matching the width of the cut-outs  23 , and has axial holes  41  built on the both ends respectively. 
         [0026]    Referring to all drawings, in combination, said biasing member  3  is placed in the hollow shaft  21 , and said sliding plate  4  is positioned to extend radially outwardly into the cut-outs  23 . Said sliding plate  4  is secured to the hub  1  with securing bolts  7  via holes  13  of the hub  1  and holes  41  of the sliding plate  4  so that said biasing member  3  is located in between the top surface  4 A of sliding plate  4  and top end inner surface  21 A of the shaft  21  extending upward from the base  2 . At the same time, base  2  is positioned and axially movable in the central channel  12  of the hub  1 . Four poles  5  are pivoted about upper engagement points  5 A on the pole slots  11  of the hub  1  on one end, four braces  6  are pivoted respectively on the brace slots  22  of the base  2  on one end, and the other ends of the four braces  6  are individually pivoted about lower engagement points  51  A on the pivoting bases  51  of the poles  5  to construct a roof staying mechanism of foldable tent or awning. 
         [0027]    In operation, referring to  FIGS. 8 and 10 , when a user wishes to open the tent or awning poles  5  are pulled away from each other which causes base  2  to be pushed upward by the biasing member  3  to approach hub  1  with the guidance of sliding plate  4  that travels downward via cut-outs  23  of shaft  21 . Meanwhile, the shaft  21  moves upward through the central channel  12  of hub  1 , and because braces  6  are separately pivoted between the base  2  and the poles  5 , the upward movement of the base  2  causes an outward movement of the poles  5  to carry out the opening function until the tent or awning is completely opened. The combination of the forces generated by the biasing member  3  and the kinetics of the braces  6  and poles  5  causes the tent to move toward its open position and remain open without an additional external force or locking mechanism. 
         [0028]    Specifically, referring to  FIG. 8 , the biasing member  3  generates an upward force  100  against the top portion of the shaft  21 A which is transferred downward (force  100 A) via shaft walls  21 B to the base  2 , which is transferred upward as force  100 B into the braces  6  (force  100 C) and moves into the pivoting base  51  which is fixed to and drives pole  5  upward to its open position. The upward force  100 C on the poles  5  generates an outward torque force  102  on the poles  5  and causes the poles  5  and braces  6  to remain extended outward in its open position. This outward torque force  102  on the poles  5  is generated from the force  100 C on the braces  6  in combination with the moment arm R 1  created by the distance between upper engagement point  5 A and lower engagement point  51 A. 
         [0029]    Referring to the phantom lines in  FIG. 9 , the mechanism has a neutral position where the poles  5  have a tendency to move to either its open or closed positions. In the neutral position, no torque force is present on the poles  5  despite the force  104  on the braces  6  because no moment arm exists. This is because the upper engagement point  5 A and lower engagement point  51 B are vertically aligned. 
         [0030]    Referring to  FIG. 9 , when a user wishes to close the tent or awning, the user pushes all the poles  5  downward and inward tending to bring them closer together and parallel to the shaft  21 , which also causes the braces  6  to move closer to an orientation that is parallel to the shaft  21 . At this time, the sliding plate  4  moves up to the top ends of the cut-outs  23  as the biasing member  3  is compressed. The combination of the forces generated by the biasing member  3  and the kinetics of the braces  6  and poles  5  causes the poles  5  and braces  6  to move toward their closed position and remain closed without an additional external force or locking mechanism. 
         [0031]    More specifically, the biasing member  3  generates an upward force  101  against the top portion of the shaft  21 A which is transferred downward (force  101 A) via shaft walls  21 B to the base  2 , which is transferred upward as force  101 B into the braces  6  (force  101 C) and moves into the pivoting base  51  which is fixed to and drives pole  5  downward and inward to its closed position. The upward force  101 C on the poles  5  generates an inward torque force  103  on the poles  5  and causes the poles  5  and braces  6  to remain substantially vertical and in its closed position. 
         [0032]    This inward torque force  103  on the poles  5  is generated from the force  101 C on the braces  6  in combination with the moment arm R 2  created by the distance between upper engagement point  5 A and lower engagement point  51 A. 
         [0033]    Referring to  FIGS. 2 and 3 , in the first embodiment, the mechanism  202  moves from its open position ( FIG. 2 ) to its closed position ( FIG. 3 ) when the sliding plate  4  moves up to the top end of the cut-outs  23  of the shaft  21  to shorten the exposed upper portion of the shaft  21  protruding above the hub  1  as the biasing member  3  is compressed to create potential energy from the subsequent opening phase. 
         [0034]    Referring to  FIGS. 4 and 5 , a roof staying mechanism  202  of foldable tent or awning  200  in the second embodiment of the present invention is shown. The difference between the first and second embodiments is that the length of the shaft  21  is such that the top end of the shaft  21  in its open and closed positions remains within the channel  12 . 
         [0035]    Referring to  FIGS. 6-9 , a roof staying mechanism  202  of foldable tent or awning  200  in the third embodiment of the present invention is shown. In this embodiment, a blind hole  12  opened downward takes the place of the channel  12  in the first embodiment. In operation, the sliding distance of the shaft  21  of the base  2  in the hub  1  is substantially equal in depth of the blind hole  12 . The blind hole  12  is completely enclosed at the top and therefore, any water deposition or dust-stratification can be avoided without affecting the opening and closing operation of the tent or awning. 
         [0036]    The present invention solves a number of problems that are present in the prior art. The present invention makes it possible for a user to pitch and fold a tent or awning on her own. This is due to the simple construction and relatively light resistance of the biasing member of the roof staying mechanism. Further, the user does not require assistance because the motion of the mechanism is fairly limited when pitching or closing the tent or awning. 
         [0037]    The present invention also allows for a foldable tent or awning to be more light-weight and easily stored. This is because the mechanism in the present invention is more compact than those of the prior art due to the short length of the biasing member. 
         [0038]    Finally, the invention does not require additional locking mechanisms to maintain the tent or awning in an open or closed position. The combination of the forces generated by the biasing member  3  and the kinetics of the braces  6  and poles  5 —more specifically, the torque forces  102 ,  103  created by the biasing member  3  in combination with moment arms R 1  and R 2 —causes the tent to remain open and closed without an additional locking mechanism or further external force. Given that locking mechanisms frequently malfunction or fail, the potential of such problems are eliminated. 
         [0039]    While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of preferred embodiments thereof. Many other variations are possible such as, for example, the mechanism could have three poles instead of four and act as a tripod for various uses. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.