Patent Abstract:
A hinge structure ( 10 ) comprises a single molded swivel hinge ( 12 ) molded initially as a unitary structure having a first portion ( 14 ) and a second portion ( 16 ). The first portion ( 14 ) includes first and second hinge pins ( 24, 26 ) extending in opposed directions from a base member ( 38 ). The second portion ( 16 ) includes hinge pin receiving portions ( 34, 36 ), the first and second hinge pins ( 24, 26 ) having an associated hinge pin receiving portion ( 34, 36 ), each hinge pin receiving portion being molded to result in a cylindrical bore ( 28, 30 ) after initial operation of the hinge structure ( 10 ). The first and second hinge pins ( 24, 26 ) are triangular in shape over its extent within its associated hinge pin receiving portion ( 34, 36 ).

Full Description:
TECHNICAL FIELD 
       [0001]    The present invention is directed to an integrally molded hinge assembly that includes a three-point hinge joined to a swivel member and a base member and method of manufacturing the integrally molded hinge assembly. 
       BACKGROUND OF THE INVENTION 
       [0002]    A known hinge comprises an assembly of parts made of plastic or metal. The components of the hinge assembly are separately manufactured and typically made from plastic or metal and are assembled together after fabrication. There is a need for a hinge assembly which consists of a minimum number of components and which can be produced without manual assembly of individual parts. 
       SUMMARY OF THE INVENTION 
       [0003]    In accordance with one example embodiment of the present invention, a hinge structure comprises a single molded swivel hinge molded initially as a unitary structure having a first portion and a second portion. The first portion includes first and second hinge pins extending in opposed directions from a base member. The second portion includes hinge pin receiving portions, the first and second hinge pins having an associated hinge pin receiving portion, each hinge pin receiving portion being molded to result in a cylindrical bore after initial operation of the hinge structure. The first and second hinge pins are triangular in shape over its extent within its associated hinge pin receiving portion. 
         [0004]    In accordance with another example embodiment of the present invention, a hinge assembly is integrally molded from a single operation comprising a hinge member having at least one three-point triangular shaped pin integrally molded and fixedly extending from the hinge member. The hinge member is made from a material. The hinge assembly also includes a swivel member having at least one cylindrical housing circumscribing and having an integrally molded connection with the three-point triangular shaped pin such that initial rotation of the swivel member with respect to the base member breaks the integrally molded connection providing a rotatable attachment between the cylindrical housing and the three-point triangular shaped pin. The swivel member is made from the same material as the hinge member during a single molding operation. 
         [0005]    In accordance with yet another example embodiment of the present invention, a method of making an integrally molded hinge assembly comprises the steps of providing a mold having cavities for forming an integrally molded hinge assembly that includes a base member and a swivel member. The method also includes the steps of inserting a first and a second set of side tooling into the mold to a prescribed distance, injecting material into the mold through at least one port, and filling the cavities with the material. The method further includes the steps of forming an integral connection between the base member and the swivel member and withdrawing the side tooling from the mold creating voids between the base member and the swivel member to enable relative movement therebetween. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The foregoing and other features and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which: 
           [0007]      FIG. 1  is a perspective view of an integrally molded hinge assembly constructed in accordance with one example embodiment of the invention; 
           [0008]      FIG. 2  is a side view of an integrally molded hinge assembly constructed in accordance with one example embodiment of the invention used in a particular example application; 
           [0009]      FIG. 3  is a side view of the integrally molded hinge assembly of  FIG. 1 ; 
           [0010]      FIG. 4A  is a dynamic side view of the integrally molded hinge assembly of  FIG. 1 , moving from a first to a second position; 
           [0011]      FIG. 4B  is a magnified dynamic partial side view of the integrally molded hinge assembly of  FIG. 4A ; 
           [0012]      FIG. 5  is a plan view of the integrally molded hinge assembly of  FIG. 1 ; 
           [0013]      FIG. 6  is an elevated view of the integrally molded hinge assembly of  FIG. 1 ; and 
           [0014]      FIG. 7  is a partial perspective view of a molding process of an integrally molded hinge assembly constructed in accordance with one example embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIG. 1 , an integrally molded hinge assembly  10 , in accordance with a first example embodiment of the invention, is shown. The integrally molded hinge assembly  10  includes a hinge structure  12  that attaches a base element  14  and swivel element  16 . The hinge assembly  10  is made of a material suitable for molding and is molded into an assembled integral unit by an in-mold assembly process. Such suitable material for the integrally molded hinge assembly could include, but is not limited to, thermoplastic polymers, metals, metal alloys, and/or any combination thereof. The molding of the materials including metals and metal alloys could be achieved in a die cast process, while thermal plastics could be used to form the integrally molded hinge assembly through, for example an injection molding process. Some examples of suitable thermoplastic polymers are polythalamide, nylon 6, nylon 66, nylon 46, Polyphenylene sulfide (PPS), Polyoxymethylene (POM), Polypropylene (PP), and Polybutylene terephthalate (PBT). 
         [0016]    The base element  14  and swivel element  16  are attachable to first and second structures  18  and  20 , respectively, using a plurality of fasteners  22 . Alternatively, an adhesive could be used to attach the base  14  and swivel  16  elements to first and second structures  18 ,  20 , or a combination of adhesive and fasteners could be used for attachment. The first and second structures,  18 ,  20  represent planer surfaces, but could be any shape or object requiring a swivel hinge connection for joining two structures for relative pivotal movement without departing from the spirit and scope of the claimed invention. In one example embodiment, the integrally molded hinge assembly  10  is used for attaching a brake line to a chassis of a motor vehicle, as depicted in  FIG. 2 . The base element  14  is secured by fasteners  22  to the underside of a vehicle  21  and a vehicle brake line  23  is supported by a clip  25  attached to the swivel element  16 . 
         [0017]    The hinge structure  12  comprises first  24  and second  26  triangular shaped hinge posts that are integrally molded within respective first and second cylindrical housings  28 ,  30 . The triangular shaped hinge posts  24 ,  26  are journaled for rotation within the cylinder housings  28 ,  30 , providing three points of substantially continuous contact with each respective cylindrical housing. The molding operation provides voids  32   a ,  32   b ,  32   c  between the triangular shaped hinge posts  24 ,  26  and the cylindrical housings  28 ,  30 , as best seen in  FIGS. 3 ,  4 A and  4 B. 
         [0018]    The first and second cylindrical housings  28 ,  30  are formed within arms  34  and  36  that extend to a desired height from swivel member  16 . It should be appreciated by those skilled in the art that the rotation of the swivel member  16  with respect to the base member  14 , represented by Θ in  FIG. 4A  is capable of substantially 360 degrees. 
         [0019]    Centrally located about the hinge structure  12  is a hub  38  having opposing first and second faces,  40   a  and  40   b  from which the first and second triangular shaped hinge posts  24 ,  26  fixedly extend. The hub  38  is attached to the base member  14 . The base member  14  is coupled to the swivel member  16  through the hub  38 , the triangular hinge posts  24 ,  26 , and the arms  34 ,  36 . 
         [0020]      FIG. 4A  illustrates the movement of the swivel element  16  about the base element  14  from a first position A to a second position B. Since the integrally molded hinge assembly  10  is molded as a single piece, initial rotation of the swivel element  12  with respect to the base element  14  breaks the molded connection between the triangular hinge posts  24 ,  26  and their respective cylinder housings  28  and  30  at break points  42 , as illustrated in  FIG. 4B . The initial rotation breaks the triangular hinge post connections just at the tips of the triangles such that subsequent rotation is freely obtained between the swivel and base elements ( 16 ,  14 ), allowing ends  44  of the triangular hinge posts  24 ,  26  to achieve substantially continuous three-point contact with the inner diameter of their respective cylindrical housings  28  and  30 . 
         [0021]      FIG. 5  illustrates a plan view of the integrally molded hinge assembly  10 . As can be seen in  FIG. 5 , the swivel member  16  includes a relief area  46  in the form of a notch that would allow for rotation of the swivel member  16  with respect to the base member  14  without interfering or contacting the hub  38  during rotation. In an alternative example embodiment (not shown), the relief area  46  could extend laterally across the swivel member  16  between first  34  and second  36  arms.  FIG. 6  illustrates an elevated end view of the integrally molded hinge assembly  10  of  FIG. 5 . 
         [0022]      FIG. 7  is a schematic view of a method of molding the integrally molded hinge assembly  10  in accordance with one example embodiment of the present invention. The hinge structure  12 , base element  14 , and swivel element  16  are formed as one assembled unit during an in-mold assembly process, such as injection molding. The assembled unit of the hinge structure  12 , base element  14 , and swivel element  16  are molded into a single structure, eliminating the need for multiple parts and costly post-molding assembly processes. In addition to the reduced assembly costs, the integrally molded hinge assembly  10  eliminates quality issues, such as disassembly of the connecting hinge pieces, since disassembly is not possible without completely destroying the hinge. This eliminates the risks associated with conventional hinges that may become disassembled during operation, especially if exposed to an environment having a significant or a sustained amount of vibration. 
         [0023]    In accordance with an example embodiment of the present invention, a molding assembly  50  includes an upper mold  52  and a lower mold  54 . The upper  52  and lower  54  molds contain cavities for forming the components that make up the integrally molded hinge assembly  10 , but are not shown for simplicity. Also for simplicity, sprues, gates, runners, and mold supports have been omitted. The molding assembly includes an injection molding station  56  for injecting the hinge assembly material into the mold cavities that define the integrally molded hinge assembly  10 . It should be appreciated by those skilled in the art that the number of injection molding stations and their locations can vary without departing from the spirit and scope of the claimed invention. 
         [0024]    Prior to injecting the material into the mold assembly  50 , tooling comprising side action assemblies  62  and  64  is inserted through respective side apertures  58  and  60  of the mold assembly  50  until engaging internal stops located at positions A in  FIG. 7  on the faces  40   a  and  40   b  of the hub  38 . After the material is injected into the mold assembly  50  and cooled for a prescribed period of time, the side action assemblies  62 ,  64  are withdrawn from the mold assembly  50  as depicted in  FIG. 7  to positions B. The removal of the side action assemblies  62 ,  64  produces the triangular shaped hinge posts  24 ,  26 , cylindrical housings  28 ,  30 , and the voids  32   a ,  32   b , and  32   c  therebetween. 
         [0025]    The side tool assemblies  62 ,  64  external constructions include a semi-circular geometrical configuration  62   a ,  62   b ,  62   c ,  64   a ,  64   b ,  64   c , such that their interaction results in the cylindrical housing  28 ,  30  that provides a bearing surface for the triangular shaped hinge posts  24 ,  26 . While the side tool assemblies internal constructions provide a planer surface  62   a ,  62   b ,  62   c ,  64   a ,  64   b ,  64   c , such that their interaction results in the three-point triangular hinge posts  24 ,  26  leaving a prescribed integral connection with the housings that would allow separation upon initial rotation of the swivel member  16  about the base member  14 . After the initial rotation, enough material remains at the ends  44  of the triangular shaped hinge posts  24 ,  26  to provide continuous contact with the cylindrical housings  28 ,  30 . 
         [0026]    The side tool assemblies  62   a ,  62   b ,  62   c ,  64   a ,  64   b ,  64   c  may be the same length and connected at the same point, but are illustrated in a staggered configuration for purposes of clarity in the molding process. After the side tool assemblies  62 ,  64  are removed, the upper  52  and lower  54  molds are separated, and the integrally molded hinge assembly  10  is ejected from the mold assembly  50 , thereby completing the molding process. 
         [0027]    From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. For example, it should be understood by those skilled in the art that the base element  14  is equally suitable for rotating about the swivel element  16  and that an unlimited number of surfaces could be represented by the first and second structures,  18  and  20 , for attaching objects or closing plastic retainers, containers, covers and the like without departing from the spirit and scope of the claimed invention. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.

Technology Classification (CPC): 4