Abstract:
A collapsible bag expander made by bending a patterned cardboard into shape, enabling coupled pairs of hooked portions of border flaps of panels of the patterned cardboard to be respectively secured together by elastic bands so that the bag expander is automatically forced by the spring power of the elastic band to expand and to support the collapsible bag in shape after removable of the collapsible bag from the polybag, which packs the collapsible bag in the collapsed condition.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a collapsible bag expander, and more particularly to such a collapsible bag expander, which is made of a patterned cardboard, and which expands automatically to support the collapsible bag in shape after removal of the collapsible bag from the packing material. 
     In order to support a backpack, travel bag, or any of a variety of collapsible bag in shape for exhibition, stuffing paper or like material is commonly used to stuff the bag. However, it is inconvenient to stuffing a collapsible bag with stuffing material. Further, when collapsing the collapsible bag, the stuffing material must be taken away. In order to eliminate these problems, various bag expander means have been developed. FIGS. 1 and 2 show a prior art bag expander for this purpose. This structure of bag expander is comprised of two folding panels and a stretcher connected between the folding panels. The stretcher has two coupling flaps at two distal ends respectively fastened to a respective coupling hole on each folding panel. This structure of bag expander is not satisfactory in function because it tends to be deformed and, the stretcher tends to be forced away from the coupling hole on each folding panel. FIGS. 3 and 4 show another structure of bag expander according to the prior art. This structure of bag expander comprises two symmetrical expander elements or substantially U-shaped cross section coupled together, and spring means fastened to the expander elements to secure the expander elements in the extended position. The expander elements each have two side panels, and coupling means at the side panels. The coupling means at the side panels of one expander element are respectively fastened to the coupling means at the side panels of the other expander element. The spring means are respectively fastened to the coupled coupling means to secure the expander elements in the extended position. Further, the side panels of the expander elemenets can be folded inwards to collapse the bag expander. This structure of bag expander has less industrial value because it is complicated and expansive. 
     The present invention has been accomplished to provide a bag expander, which eliminates the aforesaid drawbacks. It is one object of the present invention to provide a bag expander, which is simple and inexpensive. It is another object of the present invention to provide a bag expander, which automatically extends out to support the bag in shape after removal of the bag from the packing material. According to one embodiment of the present invention, the bag expander is compirised of a patterned cardboard, which is folded into a three-dimensional configuration to support the bag in shape, and two elastic bands, which secure the patterned cardboard in the folded shape. The patterned cardboard comprises a base panel, the base panel having a top side, a bottom side, and two opposite lateral sides, two opposite side panels extended from the two opposite lateral sides of the base panel, two supporting flaps respectively longitudinally extended from the side panels at a top side, and two coupling flaps respectively transversely extended from two opposite lateral sides of the bottom panel in reversed directions, the side panels each having a hooked portion remote from the supporting flaps, the coupling flaps each having a hooked portion respectively hooked up with the hooked portions of the side panels. The elastic bands are respectively fastened to the coupled hooked portions of the side panels and the coupling flaps to secure the patterned cardboard in the folded shape. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a prior art bag expander installed in a collapsible bag and collapsed. 
     FIG. 2 illustrates the prior art bag expander and collapsible bag of FIG. 1 set in the expanded condition. 
     FIG. 3 illustrates another structure of prior art bag expander installed in a collapsible bag and collapsed. 
     FIG. 4 illustrates the prior art bag expander and the collapsible bag of FIG. 3 set in the expanded condition. 
     FIG. 5 is an extended plain view of a bag expander according to a first embodiment of the present invention. 
     FIG. 6 is a perspective view of the bag expander according to the first embodiment of the present invention. 
     FIG. 7 illustrates the bag expander of the first embodiment of the present invention collapsed. 
     FIG. 8 is a perspective view of a backpack when expanded according to the present invention. 
     FIG. 9 is a sectional view showing the bag expander collapsed with the backpack according to the present invention. 
     FIG. 10 is a sectional view showing the backpack and the bag expander expanded according to the present invention. 
     FIG. 11 is extended plain view of a bag expander according to a second embodiment of the present invention. 
     FIG. 12 is a perspective view of the bag expander according to the second embodiment of the present invention. 
     FIG. 13 is a sectional view showing the bag expander of the second embodiment of the present invention installed in a travel bag and collapsed with the travel bag. 
     FIG. 14 is a sectional view showing the travel bag and the bag expander of the second embodiment of the present invention expanded. 
     FIG. 15 is a perspective view of FIG.  14 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 5 and 6, a collapsible bag expander is made of a patterned card board and adapted to expand a bag, comprising a base panel  10 , which fits the back panel of the bag to be expanded, two opposite side panels  11  and  11 ′ extended from two opposite lateral sides of the base panel  10 , which fit the two opposite side panels of the bag to be expanded, and a bottom panel  12  extended from the bottom side of the base panel  10 , which fits the bottom panel of the bag to be expanded, two supporting flaps  110  and  110 ′ respectively longitudinally extended from the side panels  11  and  11 ′ at a top side, and two coupling flaps  120  and  121  respectively transversely extended from two opposite lateral side of the bottom panel  10  in reversed directions. The side panels  11  and  11 ′ each have a hooked portion  111  or  111 ′ remote from the supporting flaps  110  or  110 ′. The coupling flaps  120  and  121  each have a hooked portion  1201  or  1211  for hooking up with the hooked portion  111  or  111 ′ of one side panel  11  or  11 ′. The coupling flaps  120  and  121  are respectively bent inwards, and then the bottom panel  12  and the side panels  11  and  11 ′ are respectively bent inwards relative to the base panel  10 , and then the hooked portions  1201  and  1211  of the bottom panel  12  are respectively hooked up with the hooked portions  111  and  111 ′ of the side panels  11  and  11 ′, and then two elastic bands  13  are respectively fastened to the hooked portions  111  and  1201 ;  111 ′ and  1211  to secure the bottom panel  12  and the side panels  11  and  11 ′ in the coupled condition, and then the supporting flaps  110  and  110 ′ are respectively bend inwards and perpendicularly disposed in contact with the base panel  10 , and thus the collapsible bag expander is set in the operative position (see FIG.  6 ). 
     Referring to FIGS. 7 and 6, before inserting into the bag to be expanded, the supporting flaps  110  and  110 ′ are respectively bent inwards and closely attached to the inner surface of the side panels  11  and  11 ′, and then the bottom panel  12  and the side panels  11  and  11 ′ are respectively bent inwards and closely attached to the surface of the base panel  10 , enabling the side panels  11  and  11 ′ to be retained between the base panel  10  and the bottom panel  12 , and thus the collapsible bag expander is collapsed (see FIG.  7 ). 
     Referring to Figures from  8  through  10 , the collapsed bag expander is inserted into a bag, for example, a backpack  3 . Because the backpack  3  is packed in a polybag, the collapsible bag expander is retained in the collapsed condition inside the backpack  3  under the constraint of the polybag. After removal of the bakcpack  3  from the polybag, the backpack  3  is shaken with the hands, enabling the collapsible bag expander to be forced by the spring power of the elastic bands to extend from the collapsed position shown in FIG. 7 to the expanded position shown in FIG. 6 to support the backpack  3  in shape. 
     FIGS. 11 and 12 show an alternate form of the present invention. According to this alternate form, the collapsible bag expander is made of a patterned carboard comprising a rectangular bottom panel  23  having two short sides and two long sides, two opposite side panels  21  and  22  respectively extended from the short sides of the bottom panel  23 , two bottom panel reinforcing flaps  230  and  231  respectively extended from the long sides of the bottom panel  23 , and two pairs of side panel reinforcing flaps  210  and  211 ;  220  and  221  respectively extended from the side panels  21  and  22  at two opposite sides in longitudinal alignment with the bottom panel reinforcing flaps  230  and  231 . The bottom panel reinforcing flaps  230  and  231  each have two hooked portions  2301  and  2301 ′;  2311  and  2311 ′ near two distal ends. The side panel reinforcing flaps  210  and  211 ;  220  and  221  each have a hooked portion  2101  or  2111 ;  2201  or  2211  disposed near one end. 
     Referring to Figures from  13  through  15  and FIGS. 11 and 12 again, the side panel reinforcing flaps  210  and  211 ;  220  and  221  and the bottom panel reinforcing flaps  230  and  231  are respectively bent inwards through 90° angle, and then the side panels  21  and  22  are respectively bent inwards through 90° angle, and then the hooked portions  2301  and  2301 ′;  2311  and  2311 ′ of the bottom panel reinforcing flaps  230  and  231  are respectively hooked up with the hooked portions  2101  and  2111 ;  2201  and  2211  of the side panel reinforcing flaps  210  and  211 ;  220  and  221  to hold the bag expander in the operative position as shown in FIG. 12, and then elastic bands  24  are respectively fastened to each matched pair of hooked portions  2101  and  2311 ;  2111  and  2301 ;  2201  and  2311 ′;  2211  and  2301 ′. When in use, the side panel reinforcing flaps  210  and  211 ;  220  and  221  are respectively bend inwards to force the bottom panel reinforcing flaps  230  and  231  inwards, and then the side panels  21  and  22  are respectively bent inwards and closely attached to the surface of the bottom panel  23 , and then the collapsed bag expander is inserted into a travel bag  3 ′, and then the travel bag  3 ′ is Packed in a polybag (not shown) and retained in the collapsed condition. After removal of the travel bag  3 ′ from the polybag, the travel bag  3 ′ is shaked with the hands, enabling the bag expander to be forced by the spring power of the elastic bands  24  from the collapsed position to the extended position to support the travel bag  3 ′ in shape (see FIG.  15 ).