Patent Publication Number: US-9428038-B2

Title: Foldable tonneau cover for pick-up truck and waterproof flexible strip thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 14/109,402, filed Dec. 17, 2013, and the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a foldable tonneau cover and a waterproof seal thereof, and more particularly to a foldable tonneau cover for a pick-up truck having a waterproof flexible strip. 
     BACKGROUND OF THE INVENTION 
     A traditional pick-up truck has a cargo box used to carry various cargo. Generally, the cargo box is covered by a tonneau cover which is releasably clamped to and extended above the cargo box, so as to protect the carried cargo from adverse weather and improve the aesthetic appearance of the pick-up truck. Tonneau covers can be classified into hard-top type and soft-top type, wherein the hard-top type tonneau cover has a hard top made of rigid material, such as metal, fiberglass or the like, while the soft-top type tonneau cover has a soft top made of flexible material, such as canvas, vinyl plastic or a weather-resistant fabric. Moreover, the tonneau cover can be designed to provide a foldable function to help a user to conveniently extend or store the tonneau cover. 
     Referring now to  FIGS. 1, 2 and 3 , schematic views of a traditional foldable tonneau cover system for a pick-up truck are illustrated, wherein a tonneau cover system  10  is used to cover a cargo box  21  of a pick-up truck  20 , and the tonneau cover system  10  comprises a plurality of frame sections  11 ,  12 ,  13 , a plurality of hinges  14 , a plurality of clamps (not-shown) and at least one cover portion  15 . The number of the cover portion  15  can be one or corresponding to that of the frame sections  11 - 13  (such as three). The cover portion  15  is made of flexible or rigid material, and can be suitably fixed on the corresponding frame sections  11 - 13 . Each of the frame sections  11  is constructed by a plurality of frame members. One of the frame sections  11 ,  13  can be pivotally connected to another adjacent frame section  12  through two or more of the hinges  14 , so that all of the frame sections  11 - 13  can be adjusted to an extended position or a storage position. 
     When the frame sections  11  are in the extended position as shown in  FIG. 2 , the frame sections  11 - 13  are horizontally extended on two side walls  22  and a tailgate  23  of the cargo box  21 , and fixed thereon by the clamps, so as to cover an inner space of the cargo box  21 . When the frame sections  11 - 13  are in the storage position as shown in  FIG. 3 , the frame sections  11 - 13  are folded and stacked on a front end of the two side walls  22 , so as to expose the inner space of the cargo box  21  for placing or taking cargo. 
     In the tonneau cover system  10 , each of the hinges  14  mainly comprises two hinge portions and a pivot axis, wherein each of the hinge portions is installed on frame members of one of the frame sections  11 - 13 , while the pivot axis is pivotally connected between the two hinge portions. In order to prevent water leakage from the gap between any two adjacent frame sections  11 - 13 , side surfaces of the frame members of the two adjacent frame sections  11 - 13  are provided with a pair of laterally-extending channels (unlabeled), wherein a sealing strip  16  is disposed in each of the laterally-extending channels, respectively. Thus, when the frame sections  11  are in the extended position as shown in  FIG. 2 , the two sealing strips  16  can be abutted against each other to provide a waterproof function for the frame sections  11 - 13 . Furthermore, the external (or internal) side of each of the hinges  14  can be covered with another seal sheet (not-shown) to further enhance the waterproof function for the frame sections  11 - 13 . 
     However, in a first case that a large-area elongated piece of the seal sheet is covered on the external side of the hinge  14 , when the two adjacent frame sections  11 - 12  are folded and stacked with each other, it is easy to irregularly twist the seal sheet between two outer surfaces of the two adjacent frame members, and thus the ideal folding angle (i.e. 180 degree) between the two adjacent frame sections  11 - 12  may not be carried out due to the jam of the seal sheet. On the other hand, in a second case that a small-area elongated piece of the seal sheet is covered on the internal side of the hinge  14 , when the two adjacent frame sections  11 - 12  are horizontally extended, it is still easy to irregularly twist the seal sheet between two side surfaces of the two adjacent frame members, and thus the ideal extension angle (i.e. 0 degree) between the two adjacent frame sections  11 - 12  may not be carried out due to the jam of the seal sheet; and when the two adjacent frame sections  11 - 12  are folded and stacked with each other, it is easy to generate a pull force between two outer surfaces of the two adjacent frame members because the curve length of the seal sheet may be insufficient, and thus the ideal folding angle (i.e. 180 degree) between the two adjacent frame sections  11 - 12  may not be carried out due to the insufficient curve length of the seal sheet. 
     Moreover, the pivot axis of the hinge  14  is installed at a fulcrum position between the two adjacent frame members, and thus occupies a certain space of the gap therebetween in the horizontally extended status. As a result, the pivot axis interfere with the installation and open/close operation of the seal sheet on the external or internal side of the hinge  14 , so that it may increase the installation offset between the hinge  14 , the seal sheet and the frame members. As a result, the installation yield may be affected, and the waterproof reliability thereof may be reduced. 
     As a result, it is necessary to provide a waterproof seal structure and a hinge structure for the foldable tonneau cover to solve the problems existing in the conventional technology, as described above. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a foldable tonneau cover for a pick-up truck and a waterproof flexible strip thereof, which is provided with a waterproof flexible strip continuously extended along the entire length of the two adjacent frame members without being interfered with by the hidden-type hinge substantially hidden within the frame members, so as to enhance the waterproof reliability thereof. 
     A secondary object of the present invention is to provide a foldable tonneau cover for a pick-up truck and a waterproof flexible strip thereof, which is provided with at least one hidden-type hinge substantially hidden within two opposite side surfaces of frame members of two adjacent frame sections in a horizontally extended status, so as to minimize the occupied space of the hidden-type hinge and the gap between the adjacent frame sections. 
     A third object of the present invention is to provide a foldable tonneau cover for a pick-up truck and a waterproof flexible strip thereof, which is provided with at least one hidden-type hinge and a waterproof flexible strip between any two adjacent frame sections, so as to simplify the waterproof interconnection structure between the adjacent frame sections. 
     A fourth object of the present invention is to provide a foldable tonneau cover for a pick-up truck and a waterproof flexible strip thereof, which is provided with a foam core between two rigid cover plates of each frame section, so as to enhance the structural strength and waterproof reliability of the frame section. 
     To achieve the above object, the present invention provides a foldable tonneau cover of a pick-up truck, which comprises: 
     a first frame section having a plurality of first frame members; 
     a second frame section having a plurality of second frame members, wherein the adjacent first and second frame members of the first and second frame sections have two opposite side surfaces; 
     at least one hidden-type hinge pivotally connected between the opposite side surfaces of the adjacent first and second frame members; and 
     a waterproof flexible strip flexibly connected between the adjacent frame members, disposed outside the hidden-type hinge, and having at least two rigid edge rims continuously connected to and extended along the entire length of the adjacent first and second frame members, and a flexible sheet integrally and flexibly connected between the at least two rigid edge rims. 
     In one embodiment of the present invention, the at least two rigid edge rims are made of a first plastic material, the flexible sheet is made of a second plastic material, and the first plastic material has a stiffness greater than that of the flexible sheet. 
     In one embodiment of the present invention, the two opposite side surfaces of the adjacent first and second frame members have a first C-shape insertion groove and a second C-shape insertion groove, respectively, and two of the rigid edge rims of the waterproof flexible strip are inserted into the first and second C-shape insertion grooves, respectively. 
     In one embodiment of the present invention, the at least two rigid edge rims have a cross-sectional height greater than that of the flexible sheet, so that a water collection recess is defined by the at least two rigid edge rims and the flexible sheet, wherein the water collection recess faces an outer side of a gap defined between the adjacent first and second frame members in a horizontally extended status of the adjacent first and second frame members. 
     In one embodiment of the present invention, an outer surface of the first frame member has at least one first C-shape insertion groove, an outer surface of the second frame member has at least one second C-shape insertion groove, and the at least two rigid edge rims of the waterproof flexible strip are inserted into the first and second C-shape insertion grooves, respectively. 
     In one embodiment of the present invention, the outer surface of the first frame member has two of the first C-shape insertion grooves, the outer surface of the second frame member has two of the second C-shape insertion grooves, and four of the rigid edge rims of the waterproof flexible strip are inserted into the two first C-shape insertion grooves and the two second C-shape insertion grooves, respectively. 
     In one embodiment of the present invention, the first frame section has two rigid cover plates covering on the first frame members, and a foam core filled in a space defined between the two rigid cover plates and the first frame members. 
     In one embodiment of the present invention, the second frame section has two rigid cover plates covering on the second frame members, and a foam core filled in a space defined between the two rigid cover plates and the second frame members. 
     In one embodiment of the present invention, each of the first and second frame members is formed with an installation slot, a C-shaped insertion groove and a linear installation groove, wherein the foam core is filled into the C-shaped insertion groove, and an outer edge of one of the rigid cover plates is inserted into the linear installation groove. 
     In one embodiment of the present invention, at least one hole is formed between the C-shaped insertion groove and the installation slot, and the foam core is further filled into the installation slot through the hole. 
     Furthermore, the present invention provides another waterproof foldable tonneau cover for a pick-up truck, which comprises: 
     a first frame section having a plurality of first frame members; 
     a second frame section having a plurality of second frame members, wherein the adjacent first and second frame members of the first and second frame sections have two opposite side surfaces; 
     at least one hidden-type hinge pivotally connected between the adjacent first and second frame members; and 
     a waterproof flexible strip flexibly connected between the adjacent frame members, disposed outside the hidden-type hinge, and having at least two rigid edge rims continuously connected to and extended along the entire length of the adjacent first and second frame members, and a flexible sheet integrally and flexibly connected between the at least two rigid edge rims, wherein a water collection recess is defined by the at least two rigid edge rims and the flexible sheet. 
     Moreover, the present invention provides a waterproof flexible strip for a foldable tonneau cover for a pick-up truck, the foldable tonneau cover including a first frame section having a plurality of first frame members, a second frame section having a plurality of second frame members, and at least one hidden-type hinge pivotally connected between two opposite side surfaces of the adjacent first and second frame members, the waterproof flexible strip flexibly connected between the adjacent frame members, disposed outside the hidden-type hinge, and comprising: 
     at least two rigid edge rims continuously connected to and extended along the entire length of the adjacent first and second frame members; and 
     a flexible sheet integrally and flexibly connected between the at least two rigid edge rims; 
     wherein the at least two rigid edge rims have a cross-sectional height greater than that of the flexible sheet, so that a water collection recess is defined by the at least two rigid edge rims and the flexible sheet, and wherein the water collection recess faces an outer side of a gap defined between the adjacent first and second frame members in a horizontally extended status of the adjacent first and second frame members. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a traditional foldable tonneau cover system of a pick-up truck; 
         FIG. 2  is a partially enlarged view of the traditional foldable tonneau cover system of  FIG. 1  in a horizontally extended status; 
         FIG. 3  is a partially enlarged view of the traditional foldable tonneau cover system of  FIG. 1  in a folded status; 
         FIG. 4  is a partially top view of a foldable tonneau cover of a pick-up truck according to a first embodiment of the present invention; 
         FIG. 4A  is a partially enlarged cross-sectional view of a frame section having two rigid cover plates and a foam core according to the first embodiment of the present invention; 
         FIG. 5  is a partially bottom view of the foldable tonneau cover according to the first embodiment of the present invention; 
         FIG. 6  is a partially enlarged view of the hidden-type hinge according to the first embodiment of the present invention in a partially folded status; 
         FIG. 7  is a partially enlarged and partially cross-sectional view of the hidden-type hinge according to the first embodiment of the present invention in a completely folded status, similar to  FIG. 6 ; 
         FIG. 8  is an exploded top view of the hidden-type hinge, a waterproof flexible strip and two adjacent frame members according to the first embodiment of the present invention; 
         FIG. 9A  is an assembled cross-sectional view of installing the waterproof flexible strip onto the two adjacent frame members according to the first embodiment of the present invention in the horizontally extended status; 
         FIG. 9B  is an assembled cross-sectional view of installing the waterproof flexible strip onto the two adjacent frame members according to the first embodiment of the present invention in the completely folded status; 
         FIG. 10A  is an assembled cross-sectional view of installing a waterproof flexible strip onto two adjacent frame members according to a second embodiment of the present invention in a horizontally extended status; 
         FIG. 10B  is an assembled cross-sectional view of installing the waterproof flexible strip onto the two adjacent frame members according to the second embodiment of the present invention in a completely folded status; 
         FIG. 11A  is a schematic side view of the foldable tonneau cover according to the first or second embodiment of the present invention in a folded status; and 
         FIG. 11B  is another schematic side view of the foldable tonneau cover according to the first or second embodiment of the present invention in a folded status. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings. Furthermore, directional terms described by the present invention, such as upper, lower, front, back, left, right, inner, outer, side, longitudinal/vertical, transverse/horizontal, and etc., are only directions by referring to the accompanying drawings, and thus the used directional terms are used to describe and understand the present invention, but the present invention is not limited thereto. 
     Referring now to  FIGS. 4 and 5 , partially top and bottom views of a foldable tonneau cover of a pick-up truck according to a first embodiment of the present invention are illustrated. As shown, the foldable tonneau cover designated by numeral  30  is applied to a pick-up truck (as shown in  FIG. 1 ) and comprises at least two frame sections  31 , 32 , at least one hidden-type hinge  33  and at least one waterproof flexible strip  34 , all of which will be described in more detailed hereinafter. 
     Referring to  FIGS. 4 and 4A , the number of the frame sections  31 , 32  can be two, three, four or more. In the embodiment, the foldable tonneau cover  30  is provided with a first frame section  31  and a second frame section  32 , but not limited to include additional frame section or not. The first frame section  31  has a plurality of first frame members  311 , two rigid cover plates  312  and a foam core  313 . The number of the first frame members  311  can be four, and can be made of metal (such as aluminum, iron, stainless steel, copper or alloy thereof) or engineering plastic. Each set of the first frame members  311  can be used to construct a rectangular frame and define a rectangular space within the rectangular frame. The rigid cover plates  312  are made of rigid material, such as engineering plastic (such as polyamide 6 (PA6), polyamide 66 (PA66), polypropylene (PP), acrylonitrile-butadiene-styrene (ABS) copolymer, polycarbonate (PC) or polybutylene terephthalate (PBT), without limitation) or metal (such as aluminum, iron, stainless steel, copper or alloy thereof). Two of the rigid cover plates  312  can be suitably covered and fixed on a top side and a bottom side of the first frame members  311 , and the size of the rigid cover plates  312  is slightly greater than that of the rectangular space defined by the first frame members  311 . 
     Furthermore, referring to  FIG. 4A , a cross-section of each of the first frame members  311  at the outer edge of the first frame section  31  is formed with an installation slot  311   a , a C-shaped insertion groove  311   b  and a linear installation groove  311   c , wherein the installation slot  311   a  is used to be installed with two corner members  314  (as shown in  FIGS. 4 and 5 ); the C-shaped insertion groove  311   b  is formed at an internal side of the installation slot  311   a , wherein the foam core  313  (such as urethane foam material) is filled into the C-shaped insertion groove  311   b  and the rectangular space defined between the first frame members  311  and the two rigid cover plates  312 ; the linear installation groove  311   c  is formed at a top side (and/or a bottom side) of the installation slot  311   a , wherein an outer edge of one of the rigid cover plates  312  is inserted into the linear installation groove  311   c ; and the first frame members  311  can be further formed with at least one hole  311   d  formed between the C-shaped insertion groove  311   b  and the installation slot  311   a , and the foam core  313  is thus further filled into the installation slot  311   a  through the hole  311   d.    
     Therefore, when water enters the installation slot  311   a  from the gap between the first frame members  311  and the corner members  314 , there is no space in the installation slot  311   a  to receive water, so that the water leakage and the noise caused by water in the installation slot  311   a  can be minimized and avoided. In addition, the foam core  313  is further filled into the C-shaped insertion groove  311   b , so that a reliable connection strength can be provided between the first frame members  311  and the foam core  313  in the rectangular space defined by the first frame members  311  and the two rigid cover plates  312 . 
     Referring to  FIGS. 4, 4A and 5 , similarly, the second frame section  32  also has a plurality of second frame members  321 , two rigid cover plates  322  and a foam core  323 , all of which have structures and functions substantially the same as the corresponding first frame members  311 , the rigid cover plates  312  and the foam core  313 , as described above, so that the detailed description thereof will be omitted herein. 
     Referring to  FIGS. 6 and 7 , a partially enlarged view of the hidden-type hinge  33  in a partially folded status and a partially enlarged and partially cross-sectional view of the hidden-type hinge  33  in a completely folded status are illustrated. 
     According to the foldable tonneau cover  30  of the present invention, one of the frame sections (e.g. the first frame section  31 ) can be pivotally connected to another adjacent frame section (e.g. the second frame section  32 ) through one, two or more of the hidden-type hinge  33 , so that all of the two adjacent frame sections  31 , 32  can be pivotally rotated to an extended position or a storage position. When the two adjacent frame sections  31 , 32  are in the extended position, the frame sections  31 , 32  are horizontally extended on two side walls and a tailgate of a cargo box (as shown in  FIG. 1 ), so as to cover an inner space of the cargo box. When the frame sections  31 , 32  are in the storage position, the frame sections  31 , 32  are folded and stacked on a front end of the two side walls, so as to expose the inner space of the cargo box. 
     In the embodiment, the adjacent first and second frame members  311 , 321  of the adjacent first and second frame sections  31 , 32  have structures different from that of the first and second frame members  311 , 321  at the outer edge of the first and second frame sections  31 , 32 , wherein two opposite side surfaces of the adjacent first and second frame members  311 , 321  of the adjacent first and second frame sections  31 , 32  are correspondingly formed with a first/second embedded hole  310 , 320  and a first/second C-shape insertion groove  311   e , 321   e , respectively, wherein the hidden-type hinge  33  is substantially received in the first and second embedded holes  310 , 320  when the first and second frame sections  31 , 32  are horizontally extended relative to each other; and the hidden-type hinge  33  is partially exposed out of the first and second embedded holes when the first and second frame sections  31 , 32  are rotated or folded relative to each other. 
     For more details, referring now to  FIG. 8 , each of the hidden-type hinge  33  comprises: a first embedded body  331 , a second embedded body  332 , at least one first sliding member  333 , at least one second sliding member  334 , a central axis  335 , a first pivotal shaft  336 , a second pivotal shaft  337 , a first sliding shaft  338  and a second sliding shaft  339 , all of which are made of metal, such as stainless steel, aluminum, iron, copper or alloy thereof, without limitation. 
     Referring to  FIGS. 6, 7 and 8 , in the embodiment, the first embedded body  331  is substantially entirely (or mostly) embedded in the first embedded hole  310  of the first frame member  311 ; the second embedded body  332  is substantially entirely (or mostly) embedded in the second embedded hole  320  of the second frame member  321 ; the first sliding member  333  is pivotally connected to the first embedded body  331  by the first pivotal shaft  336  and slidably connected to the second embedded body  332  by the second sliding shaft  339 ; the second sliding member  334  is pivotally connected to the second embedded body  332  by the second pivotal shaft  337  and slidably connected to the first embedded body  331  by the first sliding shaft  338 ; and a central portion of the first and second sliding members  333 , 334  are commonly pivotally connected to the central axis  335 . The hidden-type hinge  33  preferably has two of the first sliding members  333  and two of the second sliding members  334 , both of which are alternately arranged with each other and rotatably connected with each other by the central axis  335 . 
     As shown in  FIGS. 5 and 6 , the first and second embedded bodies  331 ,  332  have a first receiving space  331   a  and a second receiving space  332   a , respectively, to commonly receive the first and second sliding members  333 , 334 . The first receiving space  331   a  of the first embedded body  331  has a pair of first pivotal holes (unlabeled) and the first pivotal shaft  336 , the first pivotal shaft  336  has two ends fixed on the two first pivotal holes, and one end of the first sliding member  333  is pivotally connected to the first pivotal shaft  336 . Similarly, the second receiving space  332   a  of the second embedded body  332  has a pair of second pivotal holes (unlabeled) and the second pivotal shaft  337 , the second pivotal shaft  337  has two ends fixed on the two second pivotal holes, and one end of the second sliding member  334  is pivotally connected to the second pivotal shaft  337 . 
     Furthermore, as shown in  FIGS. 6 and 7 , the first receiving space  331   a  of the first embedded body  331  has a pair of first sliding grooves  331   b  and the first sliding shaft  338 , the first sliding shaft  338  has two ends slidably disposed in the two first sliding grooves  331   b , and the other end of the second sliding member  334  is pivotally connected to the first sliding shaft  338 . Similarly, the second receiving space  332   a  of the second embedded body  332  has a pair of second sliding grooves  332   b  and the second sliding shaft  339 , the second sliding shaft  339  has two ends slidably disposed in the two second sliding grooves  332   b , and the other end of the first sliding member  333  is pivotally connected to the second sliding shaft  339 . 
     Referring back to  FIGS. 4 and 5 , when the first and second frame sections  31 , 32  are horizontally extended relative to each other (i.e. in an extended status), the first and second sliding members  333 , 334  are substantially entirely received in the first and second embedded bodies  331 , 332 , wherein the first and second sliding members  333 , 334  are used to interconnect the first and second frame sections  31 , 32  with each other; and referring to  FIGS. 6 and 7 , when the first and second frame sections  31 , 32  are rotated or folded relative to each other (i.e. in a partially or completely folded status), the first and second sliding members  333 , 334  can partially slide out of the first and second embedded bodies  331 , 332 , wherein the first and second sliding members  333 , 334  also can be used to interconnect the first and second frame sections  31 , 32  with each other. 
     Referring now to  FIGS. 8 and 9A-9B , the foldable tonneau cover  30  further comprises a waterproof flexible strip  34  flexibly connected between the adjacent frame members  311 , 321  and disposed outside/above the hidden-type hinge  33  (i.e. relatively close to the outer surface of the first and second frame members  311 , 321 ; or close to the ambient environment outside the first and second frame members  311 , 321 ), wherein the waterproof flexible strip  34  has two rigid edge rims  341  and a flexible sheet  342 , the two rigid edge rims  341  are used to be continuously connected to and extended along the entire length of the adjacent first and second frame members  311 , 321 ; and the flexible sheet  342  is integrally and flexibly connected between the two rigid edge rims  341 . In the embodiment, the two rigid edge rims  341  are made of a first plastic material, the flexible sheet  342  is made of a second plastic material, and the first plastic material preferably has a stiffness (rigidity) greater than that of the second plastic material. 
     Furthermore, in the horizontally extended status, the first C-shape insertion groove  311   e  and the second C-shape insertion groove  321   e  are formed at two opposite side surfaces of the adjacent first and second frame members  311 , 321 , respectively, and the first C-shape insertion groove  311   e  is corresponding to second C-shape insertion groove  321   e , wherein the two rigid edge rims  341  of the waterproof flexible strip  34  are inserted into the first and second C-shape insertion grooves  311   e , 321   e , respectively, and the flexible sheet  342  is continuously connected to and extended along the entire length of a gap defined between the adjacent first and second frame members  311 , 321 . Meanwhile, the two rigid edge rims  341  have a cross-sectional height greater than that of the flexible sheet  342 , so that a water collection recess  340  is defined by the two rigid edge rims  341  and the flexible sheet  342  (as shown in the cross-sectional view of  FIG. 9A ), wherein the water collection recess  340  faces an outer side of the gap between the adjacent first and second frame members  311 , 321  in the horizontally extended status. Water collected by the water collection recess  340  or the first and second C-shape insertion grooves  311   e , 321   e  can be further drained outward from draining holes (not-shown) formed two ends of the adjacent first and second frame members  311 , 321 . 
     In the folded status, the first frame member  311  is rotated about 180 degree relative to the second frame member  321 , so that the two opposite side surfaces of the adjacent first and second frame members  311 , 321  formed with the first and second C-shape insertion grooves  311   e , 321   e  are not aligned with each other again, while the flexible sheet  342  is bent to be a curved shape and still provides a waterproof effect for the adjacent first and second frame members  311 , 321 . 
     In addition, as shown in  FIGS. 9A-9B , the first embedded body  331  is substantially mostly embedded in the first embedded hole  310  of the first frame member  311 , wherein a small portion of the first embedded body  331  is protruded from the side surface of the first frame member  311 ; Similarly, the second embedded body  332  is substantially mostly embedded in the second embedded hole  320  of the second frame member  321 , wherein a small portion of the second embedded body  332  is protruded from the side surface of the second frame member  321 . 
     Referring now to  FIGS. 10A and 10B , assembled cross-sectional views of installing a waterproof flexible strip onto two adjacent frame members according to a second embodiment of the present invention in a horizontally extended status and in a completely folded status are illustrated and similar to  FIGS. 9A and 9B  of the first embodiment, so that the second embodiment uses similar terms or numerals of the first embodiment. As shown, the difference of the second embodiment is that: the two opposite side surfaces of the adjacent first and second frame members  311 , 321 , the structure of the waterproof flexible strip  34  and the position of the first and second C-shape insertion groove  311   e , 321   e  are further modified. 
     For more details, the two opposite side surfaces of the adjacent first and second frame members  311 , 321  of the first and second frame sections  31 , 32  are correspondingly formed with a first recessed groove  311   f  and a second recessed groove  321   f , respectively, and the first and second embedded holes  310 , 320  are formed within the first and second recessed grooves  311   f , 321   f , respectively, so that a larger front panel portion of the first and second embedded body  331 , 332  (as shown in  FIGS. 6 and 8 ) can be received in the first and second recessed grooves  311   f , 321   f , respectively, and the first and second embedded holes  310 , 320  can be a smaller hole for only receiving a smaller rear insertion portion of the first and second embedded body  331 , 332 . Thus, the hole machining of the first and second embedded body  331 , 332  can be simplified. 
     Furthermore, an outer surface of the first frame member  311  has at least one first C-shape insertion groove  311   e , an outer surface of the second frame member  321  has at least one second C-shape insertion groove  321   e , and the at least two rigid edge rims  341  of the waterproof flexible strip  34  are inserted into the first and second C-shape insertion grooves  311   e , 321   e , respectively. Preferably, the outer surface of the first frame member  311  has two of the first C-shape insertion grooves  311   e , the outer surface of the second frame member  321  has two of the second C-shape insertion grooves  321   e , and four of the rigid edge rims  341  of the waterproof flexible strip  34  are inserted into the two first C-shape insertion grooves  311   e  and the two second C-shape insertion grooves  321   e , respectively. The flexible sheet  342  is further horizontally extended leftward and rightward from the leftmost and rightmost rigid edge rims  341 , so as to form an extended portion  343  to cover the first and second C-shape insertion grooves  311   e , 321   e  on the outer surface of the first and second frame member  311 , 321 . The two first C-shape insertion grooves  311   e  and the two second C-shape insertion grooves  321   e  can be used as a dual water collection recess structure, respectively. Therefore, water collected by two of the dual water collection recess structure (i.e. the first and second C-shape insertion grooves  311   e , 321   e ) can be further drained outward from draining holes (not-shown) formed two ends of the adjacent first and second frame members  311 , 321 . 
     Referring now to  FIGS. 11A and 11B , schematic side views of two types of the foldable tonneau cover according to the first or second embodiment of the present invention in a folded status are illustrated. As shown in  FIG. 11A , the foldable tonneau cover  30  comprises a first frame section  31 , a second frame section  32 , a spacer frame section  35  and a third frame section  36  in turn, wherein the three frame sections  31 , 32 , 36  have substantially identical or similar size; the spacer frame section  35  has a smaller size than the size of each of the frame sections  31 , 32 , 36 ; at least one hidden-type hinge  33  (the number may be one, two or three) and one waterproof flexible strip  34  of the first or second embodiment are installed between any two adjacent frame sections  31 , 32 , 35 , 36 . Because the foldable tonneau cover has the spacer frame section  35 , the three frame sections  31 , 32 , 36  can be completely folded for storage. 
     Similarly, as shown in  FIG. 11B , the foldable tonneau cover  30  comprises a first frame section  31 , a second frame section  32 , a spacer frame section  35 , a third frame section  36  and a fourth frame section  37  in turn, wherein the four frame sections  31 , 32 , 36 , 37  have substantially identical or similar size; the spacer frame section  35  has a smaller size than the size of each of the frame sections  31 , 32 , 36 , 37 ; at least one hidden-type hinge  33  and one waterproof flexible strip  34  of the first or second embodiment are installed between any two adjacent frame sections  31 , 32 , 35 , 36 , 37 . Because the foldable tonneau cover has the spacer frame section  35 , the four frame sections  31 , 32 , 36 , 37  can be completely folded for storage. 
     As described above, in comparison with the traditional waterproof foldable tonneau cover, the foldable tonneau cover  30  of the present invention as shown in  FIGS. 4 to 9B  is provided with at least one hidden-type hinge  33  substantially entirely (or mostly) hidden within frame members  311 , 321  of two adjacent frame sections  31 , 32  in an horizontally extended status, so as to minimize the occupied space of the hidden-type hinge  33  and the gap between the adjacent frame sections  31 , 32 . Furthermore, a waterproof flexible strip  34  is provided to be continuously extended along the entire length of the two adjacent frame members  31 , 32  without being interfered with by the hidden-type hinge  34  substantially entirely (or mostly) hidden within frame members  311 , 321 , so as to enhance the waterproof reliability thereof. The hidden-type hinge  34  and the waterproof flexible strip  34  between any two adjacent frame sections  31 , 32  is also advantageous to simplify the waterproof interconnection structure between the adjacent frame sections. Moreover, a foam core  313 , 323  is provided between two rigid cover plates  312 , 322  of each frame section  31 , 32 , so as to enhance the structural strength and waterproof reliability of the frame section  31 , 32 . 
     The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.