Abstract:
The invention provides cardboard-based structures comprising two or more, generally elongated elements angled with respect to one another and being cut out of a multi-layered cardboard-based piece that comprises at least two layers of a single cardboard sheet folded about a longitudinal reinforcing member. The invention further provides frames, preferably human-powered vehicle frames, constructed from structures of the invention, as well as methods for producing structures of the invention.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 14/425,288 filed on Mar. 2, 2015, which is a National Phase filing under 35 C.F.R. §371 of, and claims priority to PCT Patent Application No. PCT/IL2013/050824, filed on Oct. 13, 2013, which claims the priority benefit under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 61/787,292 filed Mar. 15, 2013, the contents of all of which are hereby incorporated in their entireties by reference. 
     
    
     TECHNOLOGICAL FIELD AND BACKGROUND 
       [0002]    The present invention relates to a structure made of or comprising cardboard that may, for example, be a component in a frame, e.g. a frame of a human-powered vehicle such as a bicycle. 
         [0003]    WO11067742 discloses a human-powered land vehicle sufficiently rigid so as to transport a human rider. The vehicle is constructed from pulpably recyclable and shreddably recyclable materials. 
       GENERAL DESCRIPTION 
       [0004]    The present invention provides a structure made of or comprising cardboard. Typically, the structure provided by the present invention comprises cardboard as a major component. At times, the structure may also comprise some reinforcing members or elements made of material other than cardboard, e.g. wood, or may comprise cardboard-based elements that are articulated to one another by connecting elements made of material other than cardboard, e.g. wood, metal, etc. 
         [0005]    Provided by one aspect of the invention is a structure comprising two or more generally elongated elements, i.e. at least a first and a second elongated elements, angled with respect to one another that are cut out of a multi-layered cardboard-based piece. The term “generally elongated” should be understood to mean that the element has a length dimension that is significantly more prominent than other dimensions of the element. The generally elongated element may have an overall shape resembling a rod, a beam, etc. 
         [0006]    The cardboard-based piece comprises at least two layers of a single cardboard sheet that is folded about a longitudinal reinforcing member to thereby define a two-layered structure with longitudinal fold region at its end, said region comprising the reinforcing member embraced by portions of the cardboard sheet. At least a first of said elongated elements extends along and comprises at least a portion of the fold region. 
         [0007]    The cardboard sheet may be of a kind comprising (i) at least one low-density layer made of paper, heavy duty paper or cardboard (for ease of reference the term “paper”, will be used hereinafter to refer collectively to paper, heavy duty paper or cardboard) arranged to define a plurality of cells or voids, e.g., formed by corrugated, fluted or otherwise loosely packed paper sheets or strips that define a plurality of voids therebetween, and comprising (ii) one or more liner cardboard sheets lined at one side or both sides of the low-density layers (namely sandwiching the low-density layer between them). Examples of such cardboard panels are such known as “corrugated cardboard”, which consists of a fluted or corrugated paper panel(s) or strip and one or two flat linerboards at one or both (i.e. sandwiching) sides of the fluted or corrugated paper; and may also be such referred to as “honeycomb cardboard”. The corrugated or honeycomb cardboard sheets may be single-walled or multi-walled cardboard sheets. These terms are also meant to encompass heavy-duty cardboard of various strengths, ranging from a simple arrangement of a single thick panel of paper to complex configurations featuring multiple corrugated, honeycomb and other layers. 
         [0008]    According to one embodiment, the at least two elongated elements are integral with one another and are cut as a single integral structure out of said cardboard piece. 
         [0009]    By another aspect, the present invention provides a method for manufacturing a structure made of or comprising cardboard. The method comprises folding a cardboard sheet about a longitudinal member to thereby form a generally planar two-layer cardboard-based piece with a longitudinal fold region at its edge. The structure is then cutout from the planar two-layer cardboard-based piece, the structure comprises at least two integral elongated elements angled with respect to one another, at least one of which two elements extends along said fold region. 
         [0010]    The reinforcing member has typically a substantially rounded cross-section, e.g. circular, ellipsoid or oval cross-section. The reinforcing member is typically, though not exclusively, made of cardboard or wood. Other materials, such as plastic, metal, etc. are also possible. 
         [0011]    The first elongated element may be made to comprise substantially all or only a portion of said fold region. By some embodiments, a single cardboard piece may be used to produce two or a plurality of identical or different structures of the kind provided by the invention. 
         [0012]    The reinforcing element that is embedded within the fold region typically extends the length of the first elongated element. By some embodiments of the invention, the structure also comprises a support element that extends between the first and the second elongated elements, typically angled with respect to both and providing additional reinforcement to the structure. The reinforcement element may also be made of cardboard and may typically also be cut out of said cardboard piece, a priori integral with the two elongated elements. However, it is also possible to construct a support element separately and connect it subsequently in a proper way to the two elongated elements. 
         [0013]    The at least two elongated elements, even if integrally formed, may have free ends typically designed for connection to other structures or structural elements, e.g. by the use of appropriate connectors or connecting members, e.g. such that are formed or embedded within said structure. 
         [0014]    By some embodiments of the invention, the first elongated element has a load-bearing or bend-resistance property significantly larger (e.g. at least about 5, 10, 15, and even at least about 20 times more) than that of the longitudinal reinforcing member. The structure of the invention is typically capable of supporting a load in a direction perpendicular to said first elongated element (when said first element is supported at its two ends), which is at least about 10, 15, 20 and even at least about 25 times the weight of such structure. 
         [0015]    The structure in its entirety or its elements may comprise an external coating which may be one or more of a fire-resistant coating, liquid-resistant coating, scratch-resistant coating, and other environmental-resistant coatings. 
         [0016]    By one embodiment, the structure as defined above is a part of a frame of a human-powered vehicle. According to one specific embodiment, the structure is configured as a part of a frame of a human-powered vehicle, e.g. a bicycle. Such frame may comprise two or more parts, one or both of which are structures as provided by the invention, which may be the same or different. For example, two elements being mirror images of one another constituting the rear frame part of a bicycle frame and a third structure constituting the front part of a bicycle frame. 
         [0017]    By one embodiment of the invention, at least one of the elongated elements is configured for articulation to a pedal crank. 
         [0018]    Reference is also made to the concurrently filed and co-owned PCT application, claiming priority from U.S. provisional applications, Ser. Nos. 61/715,359 and 61/787,229, both entitled “Structural Element Comprising Cardboard” (hereinafter: “the co-owned application”), the contents of which are incorporated herein by reference. This co-owned application describes a structural element similar in its properties and manufacture to said first elongated element, mutatis mutandis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  is a schematic isometric view of a bicycle with a frame according an embodiment of the invention; 
           [0021]      FIG. 2  is a schematic isometric view of the frame shown in  FIG. 1 ; 
           [0022]      FIG. 3A  is a schematic isometric view of a front frame component of the frame shown in  FIG. 2 ; 
           [0023]      FIG. 3B  is a schematic enlarged view of a detail A shown in  FIG. 3A ; 
           [0024]      FIG. 3C  is a schematic enlarged view of detail B shown in  FIG. 3A ; 
           [0025]      FIG. 3D  is a schematic rear view of detail B shown in  FIG. 3C ; 
           [0026]      FIG. 3E  is a schematic enlarged perspective view of detail C shown in  FIG. 3A ; 
           [0027]      FIGS. 3F to 3H  are schematic section views taken along lines A-A, B-B and C-C shown in  FIG. 3A ; 
           [0028]      FIGS. 4A and 4B  are schematic respective front and isometric views of two stages of producing the front frame shown in  FIGS. 3A to 3E ; 
           [0029]      FIG. 5A  is a schematic isometric view of a rear frame component of the frame shown in  FIG. 2 ; 
           [0030]      FIG. 5B  is a schematic enlarged view of a detail D shown in  FIG. 6A ; 
           [0031]      FIG. 5C  is a schematic enlarged view of detail E shown in  FIG. 6A ; 
           [0032]      FIGS. 5D to 5E  show schematic cross-sections taken along lines D-D and E-E and F-F, respectively, of  FIG. 5A . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0033]    In the following description, although at times particular mention of a specific figure will be made, reference is mostly to the figures in their entirety. 
         [0034]    Reference is first made in particular to  FIGS. 1 and 2  showing a bicycle  100  having a steering arrangement  110 , a frame  102 , a seat  150 , wheels  160  and a crank assembly  170 . 
         [0035]    The frame  102  comprises a front frame part  120  and two rear frame parts  140 , the two being mirror images of one another. Each of the frame parts is made substantially of cardboard, as will also be further explained below. 
         [0036]    As best seen in  FIGS. 3A to 3E , the front frame part  120  comprises two integral elongated elements L 1  and L 2  and a support element  126 , which is also integrally formed with the two elongated elements L 1 , L 2 . 
         [0037]    End portions  127 L 1  and  127 L 2  of the longitudinal elements L 1  and L 2 , respectively, serve as the site for association with corresponding elements  147 L 1 ′ and  147 L 2 ′ of the rear frame part  140 , the bicycle seat  150  and the crank assembly  170 . As can be seen, the end portion  127 L 2  that couples with the crank assembly has a circular shape. 
         [0038]      FIGS. 4A and 4B  are a schematic illustration of the manner of manufacture of the front frame part  120 . As can be seen in these figures, the entire front frame part  120  is made of a single sheet of cardboard  124  that is folded about a reinforcing member that is constituted by rod  123 , extending along a fold region  121  of the cardboard sheet  124 . The reinforcing member is typically made of cardboard but may also be made of wood, plastic and other materials. The cardboard sheet is typically a two-walled corrugated, a multi-walled corrugated or honeycombed cardboard sheet. 
         [0039]    Once the sheet  124  has been folded, a left and a right portion thereof  124 A,  124 B are affixed to one another (e.g. by adhesive AD, sewing, stapling etc.) such that portions thereof firmly embrace and close around the reinforcing rod  123  and form at least a double-layer pre-production cardboard-based piece  128 . The pre-production structure shown in  FIG. 4B  can then be cut to the required shape, shown in this example (by dotted lines) to be the shape of the front frame part  120 . 
         [0040]    Consequently, the elongated member L 1  has the reinforcing rod  123  passing along the full length thereof and includes the fold region  121 , whereas the elongated element L 2 , as well as the supporting element  126 , is formed of a double-layer cardboard without a reinforcing rod passing therethrough. 
         [0041]    In this connection,  FIGS. 3F to 3H  show schematic cross-sections taken along lines A-A, B-B and C-C ( FIG. 3A ). As can be seen, each of the elements L 1 , L 2  and  126  comprises two layers of cardboard, while elongated element L 1  also includes the reinforcing rod  123  that may be made of cardboard but may also be made of wood and other materials. The reinforcing member in this specific embodiment has a circular cross-section. It should, however, be noted that it may have oval or other rounded cross-sectional shapes. Generally, the elongated element L 1  has features of the structural element of the co-owned application and its contents are incorporated herein by reference for its pertinent parts. 
         [0042]    The front and rear frame parts  120  and  140  are assembled together in the manner shown in  FIG. 2 , through use of a plurality of pins  180  (seen in  FIG. 1  and which may be made of cardboard, wood or other materials) that fit into designated through-bores  125 A,  125 B,  125 C in frame parts  120 ,  140 . Frame parts  120 ,  140  have overlapping portions and tight association may be ensured by applying adhesive AD on juxtaposed surfaces at these portions. 
         [0043]    In particular, as shown in  FIG. 3B , the front portion of the frame part  120  comprises four longitudinally-oriented blind holes  125 A in cardboard portion  124 A and  124 B and four bores  125 B normal to holes  125 A and the side surface of part  120 . This set of holes and bores serves for articulation to the front frame part  120  of the steering arrangement  110  through the use of pins (not shown) that protrude from the stem of the steering arrangement and the flaps  115  extending from the steering arrangement and attached to the side surfaces of part  120 . 
         [0044]    End portion  127 L 1  is formed with eight through-bores  125 C also perpendicular to and passing through both portions  124 A,  124 B, and configured for attachment to a corresponding end portion  147 L 1  of the rear frame part  140 . 
         [0045]    Rounded end portion  127 L 2  is provided with six through-bores perpendicular to and passing through both portions  124 A,  124 B, arranged circumferentially about the circular portion  127 L 2  and configured for attachment to a corresponding end portions  147 L 2 ′ of two rear frame parts  140 , to jointly form a crank assembly seat  172  for crank  170 . 
         [0046]    Rear frame part  140  is shown, in isolation, in  FIGS. 5A-5C . While differently configured, like frame part  120  it is constructed out of a single, two-layered cardboard piece. Frame part  140  is then cut out from that piece such that the fold region  141  with a reinforcing member embraced by cardboard sheet portions eventually forms the elongated element L 1 , similarly as the fold region  121  forms the elongated element L 1  of part  120 . For this reason, equivalent elements between the parts will be designated by similar reference numerals upped by  20 , i.e. cardboard portion  124 A of the front frame  120  is equivalent to cardboard portion  144 A of rear frame part  140 . 
         [0047]    The rear frame part  140  also comprises two longitudinal members L 1 ′ and L 2 ′ with, respective, end portions  147 L 1 ′,  147 L 2 ′ configured for attachment to the respective end portions  127 L 1 ,  127 L 2  of the front frame part  120 . 
         [0048]    As previously explained with respect to  FIGS. 4A and 4B , the entire rear frame part  140  is also made of a single sheet of cardboard  144  folded about a reinforcing rod  143 , extending along a fold region  141  of the cardboard sheet  144 . 
         [0049]    Once the sheet  144  has been folded and the portions thereof  144 A,  144 B are affixed to one another it can then be cut to the required shape of the rear frame part  140 . A rear triangular piece is the attached to the cut-out structure to constitute triangular projection  149 . 
         [0050]    Elongated member L 1 ′ has, thus, the reinforcing rod  143  passing along the full length thereof and includes the fold region  141 , whereas the elongated member L 2 ′ is formed of a double-layer cardboard without a reinforcing rod passing therethrough. This can be seen, in particular, in  FIGS. 5D and 5E . 
         [0051]    The rear frame part  140  is also formed with an axle-port  146  configured for receiving therein a rear axle of the bicycle  100  of rear wheel  160 . 
         [0052]    The front and rear frame parts  120  and  140  are assembled together in the manner shown in  FIG. 2 , through use of a plurality of pins  180  (some of which are seen in  FIG. 1  and which may be made of cardboard, wood, plastic and other materials) that fit into designated bores  125 A,  125 B,  125 C,  128 ,  145 ,  148  in the different frame parts  120 ,  140 . The different frame parts  120 ,  140  have overlapping portions and tight association may be ensured by passing the pins  180  through the bores and by applying adhesive AD on juxtaposed surfaces at these portions; and also through other means. 
         [0053]    As previously mentioned, the rear frame comprises two mirror image frame parts  140 , being attached to opposite sides of the front frame part  120 . Among others, this provides for a robust stable construction of the frame reinforcing the front frame part  120  on both sides and (the gap between the mirror image frame parts  140  receives therebetween the rear wheel  160 ). 
         [0054]    The assembled frame  102  comprising the two frame parts  120 ,  140  forms together a closed-contour structure, including the two reinforcing members  123 ,  143  provides for a robust construction configured for supporting considerable loads. In particular, the frame  102  can support the weight of at least two adult males (about 200 Kg) and/or properly transferring this weight to the wheels  160  of the bicycle  100 .