Abstract:
A motion-powered liquid sprayer that can increase the number of rotations of the pump relative to each rotation of the wheel or axle is provided. The sprayer can include a gearing assembly that employs gears to increase the number of pump revolutions as a function of the wheel or axle rotation. The sprayer can also include a gear pump that employs an over-capacity or enhanced gullet together with blow-by spacing to control consistent liquid flow relative to variable motional velocities. Further, the sprayer can include a vertically adjustable nozzle as well as a free reverse rotation wheel hub.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of pending U.S. patent application Ser. No. 12/055,070 entitled “SYSTEM AND METHOD OF FORMING A PROTECTIVE COVERING FOR A WIRE HARNESS” and filed Mar. 25, 2008. The entirety of the above-noted application is incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to a system and method for forming a protective covering for a wire harness, and more particularly, to a system and method for forming a protective covering on a wire harness for use in interconnecting electrical systems. 
       BACKGROUND 
       [0003]    The electrical systems of vehicles, such as automobiles and commercial vehicles, are intricate and continue to develop as manufacturers seek to provide more and more electrical capabilities to consumers. Early models of such vehicles had relatively few electrical systems, and many of these systems were relatively simple by today&#39;s standards. In contrast, modern electrical systems often involve numerous and complex subsystems, requiring substantial use of conductors and electronic devices for interconnecting components of the electrical systems. 
         [0004]    As the demands on electrical systems have proliferated, manufacturers have sought to control the space occupied by conductors used in the electrical systems by bundling these conductors together into harnesses. A number of different types of protective coverings have been used, from relatively simple harness coverings, such as engineered tape, woven threading, nylon braiding, asphaltic loom material etc., used to bundle conductors together, to more complicated harness coverings, such as extruded plastic and metal sleeving/conduits. Overmolded polymers (in which a polymer is molded to wholly or partially encase the wire harness) are especially desirable for use as harness coverings because they provide advantages that are not available from the use of other types of harness coverings. For example, in addition to controlling and managing the routing of numerous conductors, overmolded polymers provide protection from damage to the bundled conductors that might otherwise result from salt corrosion, heat, vibration, water, and ultraviolet radiation. 
         [0005]    These overmolded polymers must be shaped in accordance with a predetermined three-dimensional geometry, in order to fit properly in a vehicle. In the automotive and commercial vehicle industries, the overmolded polymer acts as a structural template for routing conductors and electronic devices through the desired parts of the vehicle. Spacing and volume considerations and potential paths between electrical subsystems are taken into account in determining the desired three-dimensional geometry for the harness coverings. 
         [0006]    In order to create these overmolded harness coverings in a cost-effective manner, these coverings are often formed pursuant to injection molding. The mold generally includes two halves, i.e., a bottom half and a top half, defining a cavity therebetween that corresponds to a desired shape, and therefore, the exact configuration of the mold is important. One conventional injection molding technique is reaction injection molding (RIM). In accordance with this technique, two liquid components, generally a polyol and an isocyanate, are injected under pressure into the mold corresponding to the predetermined three-dimensional geometry of the harness covering. The liquids chemically react in the mold, i.e., the molecules of the components cross-link, to form a solid thermoset polymer, generally polyurethane. 
         [0007]    The molds used in injection molding are often relatively expensive to manufacture. Generally, they are used to mass produce a high volume of identical parts and are less economical in low volume situations. Many molds are made of steel or aluminum to ensure a relatively long mold lifespan, but these materials may be relatively expensive and add to the cost of injection molding. Further, in the case of commercial vehicles, molds must be relatively large for the formation of large harnesses, which again adds to the cost of injection molding. 
         [0008]    In addition, complex geometries often involve the use of molds having complex shapes, which further adds to the cost of molding. A three-dimensional mold is very expensive, and to create the three-dimensional geometries needed for the final harness covering shape, the mold becomes very complicated and costly to construct. Typically, the use of “actions,” such as inserts or slides, in the mold allows a complex shape to be molded and, after molding, for the mold halves to be separated. The use of “actions: generally increase the fabrication cost of a harness covering by increasing the amount and complexity of the mechanisms that need to be placed in the mold and by increasing the molding time. 
         [0009]    After the two liquids are injected and mixed, the resulting mixture cures over time to form a strong protective covering that is relatively strong and lightweight. Generally, the covering cures sufficiently such that within a few minutes the harness can be removed from the mold, i.e., demolded, and handled without damage. The covering continues to cure over the next few hours and becomes increasingly rigid and solid. After curing is completed, the harness with covering is a rigid and geometrically stable structure. 
         [0010]    A need exists for a less expensive system and method for forming a harness having a predetermined three-dimensional geometry. There is also a need for a system and method for forming a harness covering that does not require the use of a separate three-dimensional mold for each desired three-dimensional geometry and that avoids the need for expensive molds to form complex geometries. Further, there is a need for an economical system and method for forming large harness covering having a desired geometry through reaction injection molding for use in commercial vehicles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a wire harness and a bottom half of a mold embodying features of the present invention; 
           [0012]      FIG. 2  is a perspective view of the wire harness disposed in the bottom half of the mold of  FIG. 1 ; 
           [0013]      FIG. 3  is a perspective view of a top half of a mold and the wire harness and the bottom half of the mold of  FIG. 1 ; 
           [0014]      FIG. 4  is a perspective view of the wire harness disposed in the bottom half of the mold of  FIG. 1  after injection molding; 
           [0015]      FIG. 5  is a perspective view of the overmolded wire harness and the bottom half of the mold of  FIG. 4 ; 
           [0016]      FIG. 6  is a perspective view of a post-molding fixture and the overmolded wire harness of  FIG. 4 ; 
           [0017]      FIG. 7  is a perspective view of the overmolded wire harness disposed in the post-molding fixture of  FIG. 6 ; 
           [0018]      FIG. 8  is a perspective view of the overmolded wire harness shown in  FIG. 7  disposed into a harness having a three-dimensional geometry; 
           [0019]      FIG. 9  is a perspective view of a second embodiment of an overmolded harness illustrating features of the present invention; 
           [0020]      FIG. 10  is a perspective view of the overmolded harness of  FIG. 9  disposed in a second embodiment of a post-molding fixture; 
           [0021]      FIG. 11  is a perspective view of the overmolded harness of  FIG. 9  after removal from the post-molding fixture of  FIG. 10 ; 
           [0022]      FIG. 12  is a perspective view of the overmolded harness of  FIG. 9  disposed in a third embodiment of a post-molding fixture; 
           [0023]      FIG. 13  is a perspective view of the overmolded harness of  FIG. 9  after removal from the post-molding fixture of  FIG. 12 ; and 
           [0024]      FIG. 14  is a perspective view of a fourth embodiment of a post-molding fixture. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    Preferred embodiments of the system and method of the present invention are shown generally in  FIGS. 1-8 . As discussed further below, the system and method make use of a mold  10  and post-molding fixture  12 . In a first phase, the mold  10  is used during an injection molding process, preferably a reaction injection molding process, to form a substantially flat harness  14  with covering  33  and having an intermediate, almost two-dimensional shape. In a second phase, the post-molding fixture  12  is used after the injection molding process to orient the harness  14  with covering  33  to a predetermined three-dimensional geometry corresponding to the desire final shape. 
         [0026]    The first phase involves injection molding to form a substantially flat and temporary geometry. A mold  10  used in a preferred embodiment can be seen in  FIGS. 1-3 . As can be seen in  FIGS. 1 and 2 , a bottom half  18  of the mold  10  is substantially rectangular in cross-section and includes a cavity portion  20  formed in its interior surface  22 . The harness  14  interconnects a first electronic connector  26  for connection to a first electrical system and a second electronic connector  28  for connection to a second electrical system. The cavity  20  preferably includes a plurality of sub-cavities  30  that correspond generally to the shape of the harness  14  and that are filled when the reaction injection molding process is initiated to form a covering  33 . One or more of the sub-cavities  30  may also correspond to the shape of an electronic connector or other device, such as the substantially rectangular sub-cavity  32  shown in  FIGS. 1 and 2  corresponding generally to the shape of the first electronic connector  26 . 
         [0027]    The mold  10  used in the preferred embodiment makes use of sub-cavities  30  in order to form a covering  33  that is corrugated. It has been found that these subcavities  30  are effective in centering the wire harness  14  in the mold  10  such that the injection molding liquid can envelop the harness  14 . Without the sub-cavities  30 , the wire harness  14  may settle in the bottom of the cavity  20  such that the bottom of the harness  14  is not properly encased during the injection molding process. Alternatively, for molds having a cavity  20  with a curvilinear section, portions of the harness  14  disposed in these curvilinear sections may not be properly enveloped during injection molding without these sub-cavities  30 . The dimensions of the sub-cavities  30  may also be designed such that the corrugated covering  33  has a desired thickness. 
         [0028]    The bottom half  18  of the mold  10  also includes leader pins  34  that may be inserted into corresponding holes  36  in the top half  38  of the mold  10  for alignment of the bottom half  18  with the top half  38 . In the preferred form shown in  FIGS. 1 and 2 , the bottom half  18  includes four pins  34  positioned near the corners of the bottom mold half  18 . The pins  34  are inserted into the holes  36  in the top half  38  to ensure proper alignment of the two mold halves  18  and  38  with one another during the injection molding process. Although pins  34  and holes  36  are used in the preferred embodiment for aligning the two mold halves  18  and  38  to one another, it should be evident that many other conventional types and shapes of alignment mechanisms, such as interlocking teeth, grooves, slots, channels, etc., may be used to align the mold halves  18  and  38  with one another. 
         [0029]    The cavity  20  in the bottom half  18  is preferably shaped to allow the creation of a substantially two-dimensional intermediate form. As used in a preferred embodiment shown in  FIGS. 1 and 2 , the interior surface  22  of the bottom half  18  includes several raised portions  40  that are elevated above a lower portion  42 . As should be evident, many alternative interior surface, cavity, and sub-cavity shapes are available for the bottom half  18  of the mold  10 . For example, in an alternative form, the entire interior surface  22  of the bottom half  18  may be a flat lower portion  42  and may not include any raised portions  40 . The interior surface  22  and cavity  20  preferably define a non-complex, relatively two-dimensional shape such that the mold  10  is relatively inexpensive to create, can be reused many times, and can be used to create a standardized, intermediate harness form that may be manipulated into any of a variety of complex three dimensional geometries. 
         [0030]    The bottom half  18  of the mold also preferably includes a fill groove  44 . During injection molding, the liquid components are injected into the mold  10  via the fill groove  44 , which is in fluid communication with sub-cavities  30  of the mold  10 . The mixture of liquid components flows from the fill groove  44  to the sub-cavities  30  where they subsequently envelop the wire harness  14  and, as discussed further below, cure to form a rigid protective covering about the harness  14 . 
         [0031]    A preferred form of a top half  38  of the mold  10  is shown in  FIG. 3 . It preferably includes indentations  46  corresponding to the raised portions  40  of the bottom half  18  and for disposition of the harness  14 . It may also include sub-cavities, similar to those described with respect to the bottom half  18  of the mold  10 . The top half  38  also preferably includes a mounting portion  48  for mounting and connecting the top half  38  to a mixing head  50  of an injection molding system. During operation, as described further below, the mixing head  50  dispenses an injection molding fluid through a port  50  and through the fill groove  44  of the mold  10 . 
         [0032]    As should be evident, any of a variety of molds  10  with top and bottom halves  18  and  38  defining various shapes of cavities  20  and indentations  46  can be used. The top and bottom halves are generally two portions that sealingly engage one another to form the mold  10 . The interior surfaces of the top and bottom halves  18  and  38  generally define inverse surfaces with respect to one another. In one preferred form, one half contains sub-cavities  30  that are filled with liquid during the injection molding process, while the other half does not contain sub-cavities. In alternative forms, both halves may have sub-cavities  30  that are filled during the injection molding process. Further, in other alternative forms, the mold  10  may be composed of more than two mold halves and may use “actions.” It is preferable that the mold  10  used is relatively inexpensive and re-usable because, as described below, it is used herein to create an intermediate partially-cured harness form, not the final fully-cured geometric form. 
         [0033]    Initially, as shown in  FIG. 2 , the wire harness  14  and electronic connectors  26  and  28  are positioned in and about the bottom half  18  of the mold  10 . Next, as shown in  FIG. 3 , the top half  38  of the mold  10  is positioned so as to engage the bottom half  18  and to enclose the harness  14  and electronic connectors  26  and  28  within and about the mold  10 . The leader pins  34  of the bottom half  18  are inserted into the corresponding leader pin holes  36  in the top half  38  for proper alignment of the top and bottom halves  18  and  38 . The top half  38  and bottom half  18  are preferably maintained in sealing engagement with one another to prevent the escape of injection molding fluid from the mold  10 . An injection molding press preferably applies a clamping force to keep the mold halves  18  and  38  sealingly engaged during the injection molding process. 
         [0034]    Once the harness  14  and electronic connectors  26  and  28  are enclosed within and about the mold  10 , they are preferably subjected to a reaction injection mold (RIM) process. More specifically, two liquid components, preferably a polyol and an isocyanate, are preferably dispensed from respective feed tanks at a predetermined rate through supply lines  54  and  56  to the mixing head  50 . The delivery of the components to the mixing head  50  is synchronized, or metered, to ensure a uniform chemical reaction. The liquid reactants are thoroughly mixed in the mixing head  50  by high velocity collision of the reactants under high pressure. From the mixing head  50 , the liquid polyurethane mixture is injected through a port  50  and into the mold fill groove  44  at relatively low pressure. The liquid mixture undergoes an exothermic reaction in the mold  10  to form the polyurethane polymer. 
         [0035]    The proportions of polyol and isocyanate may be formulated such that the polyurethane polymer is formed within a range of stiffnesses when fully cured. They may be formulated to form either a flexible foam or a rigid solid. Here, it is generally contemplated that the proportions of polyol and isocyanate are preferably formulated such that the polyurethane forms a rigid solid when fully cured. It is also contemplated, however, that the teachings described herein may be applied to provide a three-dimensional geometric form for foams or flexible solids. 
         [0036]    Further, although it is generally contemplated that polyurethane is formed as the protective covering, other materials may be used, such as other types of thermosetting plastics. In general thermosetting plastics are polymers that irreversibly cure to form a strong material in which molecular bonds are cross-linked. Subsequent high temperature reheating of the cured material results in decomposition of the material before a melting point is reached, and accordingly, a thermoset material cannot be melted after it is cured. Generally, thermoset polymers are more durable than thermoplastic polymers because of this three-dimensional cross-linking of bonds and are well-suited to high temperature applications. 
         [0037]    Accordingly, thermosetting polymers are generally preferred over other materials, such as thermoplastic polymers, because they are more conducive to the automotive and commercial vehicle environment. Thermosetting polymers do not melt in this heated environment, which may involve the spraying of hot oil and other liquids. In contrast, thermoplastics tend to melt at higher temperatures and they therefore generally provide a less desirable covering. 
         [0038]    Although one reaction injection molding process has been described above, other such conventional processes may be used. Reaction injection molding is generally preferred because the low internal mold pressure associated with this type of molding allows the use of relatively inexpensive mold materials. Further, reaction injection molding is especially useful in the commercial vehicle industry to economically produce large and intricately-shaped parts. More specifically, the two liquid components are generally much less viscous than liquid thermoplastic polymer used in non-reaction injection molding techniques and less clamping force is required to hold the mold  10  together, which makes the production of large parts with complex geometry more economical. Although reaction injection molding is the preferred technique used herein, it should be evident that other conventional injection molding techniques may be employed. 
         [0039]    As shown in  FIGS. 4 and 5 , after injection molding is completed, the wire harness  14  is covered with polyurethane polymer at regions corresponding to the sub-cavities  30  of the mold  10 . The top and bottom halves  18  and  38  of the mold  10  are disengaged to allow removal of the harness  14  from the mold  10 . Immediately following injection molding, the harness covering  33  has been partially cured such that the harness  14  is generally ready for demolding within a few minutes after injection such that the harness  14  can be removed and handled without damage. The harness  14  may be demolded in accordance with any conventional method of demolding, such as through the use of ejector pins, air ejection, or stripper plates. In accordance with the preferred method, the polyurethane cures over a period of hours to form a rigid harness covering  33 , and it must be removed from the mold  10  before it becomes inflexible and incapable of manipulation. As described further below, after the harness  14  is removed from the mold  10 , it is manipulated into the desired final three-dimensional geometry before it becomes irreversibly cured. 
         [0040]    The second phase of the method of the preferred embodiment involves the use of a post-molding fixture to create the desired three-dimensional geometry. Although most of the curing is generally accomplished within a few minutes after injection, i.e., on the order of 90% or 95%, the harness covering  33  is not fully cured. The remaining 5%-10%, or a similar percentage, of curing is accomplished over the next few hours, up to a maximum of about 36 hours. Manipulation of the harness covering  33  into its final three-dimensional form is accomplished during this time period before the covering  33  becomes fully cured. It is preferable, however, to position the harness  14  in the post-molding fixture  12  within about one hour of injection molding because, as more time passes between injection molding and insertion in the fixture  12 , the harness covering  33  becomes incrementally harder to manipulate and does not hold the final desired shape as well after insertion into the fixture  12 . 
         [0041]    As shown in  FIGS. 6-8 , after the harness  14  is demolded, a post-molding fixture  12  is used to perform the final geometry work. The post-molding fixture  12  may be created from any of various inexpensive materials, such as wood, paper, fiberglass, composites, cardboard, metal etc. The use of a relatively inexpensive post-molding fixture  12 , in combination with the simple mold  10  described above, allows for a significant savings in tooling costs. 
         [0042]    One preferred form of a post-molding fixture  12  that may be used is shown in  FIGS. 6 and 7 . The post-molding fixture  12  is a jig used for shaping wires, cables, harnesses, etc., and it operates to maintain the harness  14  in the desired three-dimensional orientation as the covering  33  fully cures into its rigid form. The jig is a template and guide that helps control the orientation of various arms of the harness  14  with respect to one another. The jig helps the operator to create the same harness geometry over and over again and may be repeatedly used to convert numerous harnesses having a two-dimensional intermediate geometry to their final three-dimensional form. 
         [0043]    As shown in  FIGS. 6 and 7 , in one form, the jig  12  includes a substantially flat and sturdy base portion  58 . With respect to the preferred embodiment used in the figures, the base portion  58  is substantially rectangular in cross-section but, as should be apparent, the base portion  58  may be any of various shapes. The base portion  58  also may be made of any various materials, such as plastic, wood, metal etc. The base portion  58  preferably includes a plurality of pin receiving holes  60  arranged in a predetermined orientation to allow the repeated insertion of guide pins  62  at different positions of the base portion  58 , as described further below, such that the same jig  12  may be reused for different three-dimensional geometries. 
         [0044]    As shown in  FIG. 6 , a pattern, or blueprint  64 , may be drawn, marked, scratched, or otherwise imprinted on the top surface  66  of the base portion  58 . Alternatively, a pattern may be created on a separate material such as paper, and affixed to the top of the base portion  58 , or affixed to a surface underneath a transparent base. This pattern  64  is a two-dimensional representation of the harness  14  in its final form. It is intended as an aid to manipulating the harness  14  into the desired three-dimensional geometry. The pattern  64  shown in  FIG. 6  allows the harness  14  to be manipulated from a substantially two-dimensional geometry, shown in  FIGS. 5 and 6 , to a three-dimensional geometry, shown in  FIGS. 7 and 8 . 
         [0045]    In a preferred form shown in  FIG. 6 , the jig  12  includes guide pins  62  that are used to set the final three-dimensional geometry. The guide pins  62  are preferably inserted in the pin receiving holes  60  in the base portion  58  and are disposed at predetermined positions about the base portion  58  to properly orient various portions of the harness  14 . The guide pins  62  are securely inserted or fixed to the base portion  58  to resist movement when the harness  14  is initially disposed in the jig  12 . 
         [0046]    In one preferred form, for example, the guide pins  62  may be pegs that can be removably inserted into receiving holes  60  in a board  58  having a regular or irregular grid of receiving holes  60 . The receiving holes  60  may be oriented in accordance with a predetermined pattern and spacing such that the pegs  62  may be removably inserted into holes in the board  58  corresponding to the desired geometry. Alternatively, in another preferred form, pins or nails may be driven into a board at predetermined positions corresponding to the desired geometry. It should be evident that the guide pins  62  may be any of various shapes and materials and that, similarly, the base portion  58  of the post-molding fixture  12  may be any of various shapes and materials. 
         [0047]    As discussed above, after injection molding and demolding, the harness  14  is in an intermediate, substantially two-dimensional form. The harness  14  is then preferably manipulated into its desired three-dimensional geometry and disposed in the post-molding fixture  12 . As can be seen in  FIGS. 7 and 8 , the harness  14  has been bent about the guide pins  62  and contorted such that various portions of the harness  14  are spatially oriented above or beneath other portions. Depending on the size of the harness  14 , the force required to contort the harness portions, and other considerations, the harness  14  may be manipulated manually by an individual either by hand or through the use of any convenient hand tools. 
         [0048]    Another preferred form of the post-molding fixture  70  is shown in  FIGS. 10-11 . In this example, the fixture  70  is used to shape the overmolded harness  72  shown in  FIG. 9 . The overmolded harness  72  is flatter than the harness  14  described above. Various types of inexpensive molds may be used to form the intermediate stage overmolded harness with covering, but it is generally contemplated that the molds will be substantially two-dimensional to reduce mold tooling costs. 
         [0049]    As shown in  FIG. 10 , the post-molding fixture  70  generally includes a base  74 , walls  76 ,  78 , and  80  extending from the base  74 , and a tab  82  projecting from one of the walls  80 . In this form, the base  74  is a brick-shaped, wooden block having a greater depth than the post-molding fixture  12  described above. This greater depth allows one of the arms  84  of the harness  72  to be extended downwardly in accordance with the predetermined three-dimensional geometry. 
         [0050]    Three thin walls  76 ,  78 , and  80  project upwardly from the top surface  92  of the base  74  to permit manipulation of the other three arms  86 ,  88 , and  90  of the harness  72  into the predetermined geometry. One of the upstanding walls  76  is formed to allow one arm  86  to extend in a predetermined direction in the substantially two-dimensional plane of the overmolded harness  72 . Another upstanding wall  78  forms a substantially 90 degree angle with a radiused corner  94  to orient another arm  88  to a desired curvilinear shape in the substantially two-dimensional plane. Further, in the form shown in  FIG. 10 , a tab  82  projects from the third upstanding wall  80  to orient the fourth arm  90  of the harness  72 . The tab  82  has a predetermined height and a curvilinear end  96 , which allows the fourth arm  90  to extend upwardly out of the substantially two-dimensional plane in a curvilinear manner. 
         [0051]    Another alternative preferred form of a post-molding fixture  100  is shown in  FIGS. 12-13 . The fixture  100  includes a base  102 , walls  104 ,  106 ,  108 , and  110 , and a tab  112 . In this form, the base  102  is wooden but is more irregularly shaped than the previously-described embodiment with several side surfaces. The base  102  has a wall  104  extending from one side surface  114  to orient one of the arms  116  downwardly. The base  102  also includes a curved wall  106  and two other walls  108  and  110  projecting upwardly from the top surface  114  of the base  102 . These upstanding walls  106 ,  108 , and  110  orient the other three arms  118 ,  120 , and  122  of the overmolded harness  72  in a manner similar to that described above for the previous embodiment but fashioned to create a different predetermined three-dimensional geometry. For various preferred embodiments, the portions of the harness are preferably fastened to the post-molding fixture by straps, clamps, or other conventional fastening mechanisms to orient the harness in the desired configuration. 
         [0052]    The above embodiments of the post-molding fixture  12  may be incorporated, in whole or in part, as part of a shipping container. This capability illustrates another advantage of certain preferred forms of the post-molding fixture  12 . After the harness  14  has been positioned within the post-molding fixture  12 , it is not necessary that it be removed within any specific time period, and it therefore may be left within the fixture  12  until after shipping to a desired location. Accordingly, the fixture  12  may be fashioned so that it may be easily and conveniently integrated into or function as a shipping container. 
         [0053]    Other types of post-molding fixtures  12  may also be used. In an alternative preferred form, if the desired final geometry is relatively simple, one or more ties  130  ( FIG. 14 ) may be fastened about various portions of the harness to achieve the final geometry. For example, if it is desired to simply convert a substantially two-dimensional linear harness to a substantially two-dimensional curvilinear harness, it may be sufficient to use a single wire tie  130  having ends  132  and  134  fastened together to hold two portions of the harness in the predetermined curvilinear orientation until the harness is fully cured. The tie  130  may be any of various thin strips of material used for fastening and may be made of any of various suitable materials, such as wire, string, rubber, or the like. One or more ties  130  may also be used in conjunction with preferred forms of post-molding fixtures  12 ,  70 , and  100  described above to achieve the final predetermined geometry. 
         [0054]    Accordingly, preferred embodiments have been described herein for a method and system for forming a wire harness covering according to a predetermined three-dimensional geometry. The method generally includes the steps of providing an injection mold that is substantially flat in shape and that defines a cavity therein; positioning a wire harness within the cavity of the mold; introducing an injection molding liquid into the cavity of the mold to form a covering about the wire harness; removing the wire harness from the mold before the covering is fully cured; providing a post-molding fixture corresponding to the desired predetermined three-dimensional geometry for the wire harness with covering; and positioning the wire harness with partially-cured covering within the post-molding fixture in accordance with the desired predetermined three-dimensional geometry. The system generally includes a wire harness; a substantially flat injection mold for forming a partially-cured wire harness covering having an intermediate, substantially two-dimensional shape; and a post-molding fixture including a base and guide members projecting from the base for orienting the partially-cured wire harness covering in accordance with the predetermined three-dimensional geometry. 
         [0055]    The above described method and system for creating a complex three-dimensional harness are much less expensive than conventionally making this three-dimensional shape with complex molds. Conventionally, the design of the harness covering using complex molds has been limited by the ability to extract a complex part after it has been molded. Further, in order to create some of the complex three-dimensional shapes, complex three-part and four-part reaction injection molding tools have been required or the use of multiple tools has been required, resulting in a significant increase in tooling costs and investments. These disadvantages are not present with less complex flat molds, and the above method significantly reduces tooling costs by employing a simple, reusable substantially flat mold. 
         [0056]    Cost savings arise primarily because the less complex flat molds can be tooled for a fraction of the cost involved for tooling the more complex molds that have been conventionally used. For certain molds, it has been estimated that the mold tooling costs may be reduced on the order of 50%. In other words, the cost for creating a substantially two-dimensional mold is about half that for creating a more complex, three-dimensional mold. In one specific example involving a mold made out of a composite aluminum filled epoxy, the estimated three-dimensional mold cost was about $75,000, while the estimated two-dimensional mold cost was about $40,000. 
         [0057]    The above described method and system result in an inexpensive covering that provides additional advantages over other types of coverings. For example, as addressed above, it creates a covering that provides improved environmental performance; it does not melt at high temperatures, as are prevalent in automotive and commercial vehicle environments. In addition, the resulting covering has higher bundle density; lower space requirements, especially within the automotive or commercial vehicle environment; lower weight; a more pleasing aesthetic appearance; improved reliability and durability; the capability to easily integrate accessories, such as sensors and other electronic components; part-to-part consistency; and ease of installation for original equipment manufacturers (OEMs). Thus, the resulting covering provides improved performance over other materials, including, for example, circular plastic tubing made of thermoplastics that melts at high temperatures; metal sleeving that is relatively expensive; and braided asphaltic loom material that involves a messy fabrication process. 
         [0058]    Further, although the method and system have been addressed with respect to automotive and commercial vehicle industries, it should be evident that the method and system are not limited to these industries. It is contemplated that the above described method and system may be used in other industries involving coverings for protecting conductors and other electric components and for interconnecting electrical systems and subsystems, especially where it is desirable to reduce the cost of the method. For example, it is contemplated that the above method and system might also be used in the aviation industry, with other types of vehicles, and for non-vehicle applications where it is desirable to create a protective wire harness covering. 
         [0059]    The foregoing relates to preferred exemplary embodiments of the invention. It is understood that other embodiments and variants are possible which lie within the spirit and scope of the invention as set forth in the following claims.