Patent Abstract:
A plastic wheel-balancing weight adapted to be removably secured to a wheel to correct an unbalanced wheel to prevent undesired vibrations when the wheel is rotating, the plastic wheel-balancing weight comprising a wheel-securing clip sized and designed to be resiliently secured to a wheel, and a steel weight assembled to the wheel-securing clip and at least partially covered with plastic, at least a portion of the plastic being shaped by the wheel-securing clip. An overmolded wheel-balancing weight comprising a wheel-securing clip adapted to be secured to a wheel, a weight assembled to the wheel-securing clip and overmolding material adapted to at least partially cover the weight to protect the weight, wherein at least a portion of the wheel-securing clip is an overmolding material boundary. A method of manufacturing same and a mold thereof is also provided.

Full Description:
CROSS-REFERENCE 
     This invention relates to and claim priority from U.S. provisional patent application No. 61/450,374, filed Mar. 8, 2011, entitled PLASTIC OVERMOLDED WHEEL-BALANCING WEIGHT, which is incorporated herein by reference in its entirety. Furthermore, the disclosure of the priority provisional application is contained in the Appendix hereto, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a method for covering and protecting a steel wheel-balancing weight. More precisely, the present invention relates to polymer-covered wheel-balancing weights, a method for manufacturing same and a mold for manufacturing same. 
     BACKGROUND OF THE INVENTION 
     Wheel-balancing weights (or wheel weights, wheel balance weights) are commonly used on wheeled vehicles to improve the static and dynamic balancing of the wheel assembly. To balance the wheels, each wheel is rotated with a wheel-balancing apparatus that analyses and detects uneven weight distribution thereof that could generate significant vibrations when the wheels rotate at various rotating speeds. This undesirable wheel vibration would be transmitted to the entire vehicle, if not corrected. Corrective wheel-balancing weights, when required, are secured on the circumference of the wheel on both the interior and the exterior sides of the wheel. The addition of required wheel-balancing weights corrects the polar weight distribution of the wheel assembly and balances the wheel that will rotate without inducing undesirable vibrations. 
     Legacy wheel-balancing weights are made in lead. Nowadays, environmental consciousness and regulations suggest avoiding using lead that could have an undesirable effect on our ecosystems. Replacement of lead by steel is therefore a desirable direction. 
     However, the use of steel has some drawbacks. Steel is subject to corrosion and should be protected thereagainst. Steel balancing weights can also damage the wheel it is installed on. Steel is also harder and more difficult to shape to obtain a close and precise fit between the wheel-balancing weight and the wheel it is secured thereto. Additionally, the aesthetic of steel wheel balancing weights is questionable and it might be desirable to add a more visually attractive cover. 
     Covering the wheel-balancing weights with plastic could be an advantageous alternative. However, molding plastic over the wheel-balancing weight requires a complex and expansive tooling. Issues can arise when overmolding a steel wheel balancing weight. For instance, the overmolding plastic can retract and leave a gap with the steel weight where water and dirt can enter. Some overmolding materials might difficultly manage frequent changes in temperature and react poorly to impacts thereon. The geometry of the plastic overmolding might also require complex and expansive molds and handling. 
     The junction between the overmolding material and the wheel-securing clip is a sensitive portion of the overmolded wheel-balancing weight because the overmolding material boundary merges with the wheel-securing clip generally made of a different material. 
     Therefore, there exists a need in the art for an improved method, system and apparatus for covering wheel-balancing weights with plastic, polymer or another material. There is a need in the art for such a method, system and apparatus for covering wheel-balancing weights with overmolding polymer or another material that can be easily installed, economically manufactured and operated. And there is a very perceptible need for an improved fit between a polymer-covered wheel-balancing weight and a method of manufacturing same over the existing art. 
     SUMMARY OF THE INVENTION 
     It is one aspect of the present invention to alleviate one or more of the drawbacks of the background art by addressing one or more of the existing needs in the art. 
     Accordingly, at least one embodiment of the invention provides an undercutless overmolded wheel-balancing weight, a mold for producing same and a method of overmolding a steel wheel-balancing weight adapted to prevent injecting overmolding material in the region of the overhanging wheel-securing clip. 
     At least one embodiment of the invention provides a method of overmolding a metallic wheel-balancing weight using a mold that prevents polymer injection around the wheel-securing clip that would create an undercut interfering with the ejection of the overmolded wheel-balancing weight from the mold and require a more complex mold adapted to manage overhanging portions. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a steel wheel-balancing weight with a polymer wherein the distribution of polymer around the wheel-balancing weight allows extraction of the overmolded wheel-balancing weight by simply opening the apparatus in two. 
     At least one embodiment of the invention provides a method and a mold for overmolding a wheel-balancing weight with a polymer wherein the distribution of polymer around the wheel-balancing weight allows extraction of the overmolded wheel-balancing weight by opening the mold in two along the longitudinal plan of the wheel-balancing weight. 
     At least one embodiment of the invention provides ribs disposed on the longitudinal sides of the overmolded wheel-balancing weight that help maintains the wheel-balancing weight on one halve of the mold to facilitate extraction of the overmolded wheel-balancing weight when opening the mold in two halves along the longitudinal plan of the wheel-balancing weight. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight with a polymer wherein the distribution of polymer around the clip of the wheel-balancing weight allows extraction of the overmolded wheel-balancing weight by opening the mold in two halves along the longitudinal plan of the wheel-balancing weight. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight with a polymer wherein the clip of the wheel-balancing weight substantially follows the shape of the overmolding polymer. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight with a polymer wherein the clip of the wheel-balancing weight substantially angularly extends from the overmolded polymer to offer a tight polymer-clip junction. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight with a polymer-free wheel-balancing weight clip area. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight while preventing polymer to be injected around the clip that would prevent removal from the mold by opening the mold in two. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight that uses the wheel-securing clip of the wheel-balancing weight for restricting the injection of polymer around the wheel-securing clip. 
     At least one embodiment of the invention provides a method and an apparatus for overmolding a wheel-balancing weight that reduces the thickness of the overmolding material in the area surrounding the wheel-securing clip of the wheel-balancing weight. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight that has no undercuts created by the overhanging wheel-securing clip assembled thereto. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight having no polymer within the cavity defined by the wheel-securing clip and a method of manufacturing same. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight wherein the overmolding material follows the shape of the wheel-securing clip of the wheel-balancing weight that substantially define the shape of at least a portion of the overmolding polymer. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight wherein an edge of the overmolding material radially meet the wheel securing clip of the wheel-balancing weight. 
     At least one embodiment of the invention provides a wheel-securing clip configured to secure a wheel-balancing weight to a wheel, wherein the wheel-securing clip includes a raised portion adapted to improve the junction between an edge of the overmolding material and the wheel-securing clip. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight wherein the wheel-securing clip of the wheel-balancing weight substantially contacts the injection mold and forms an injection boundary portion of the injection mold. 
     At least one embodiment of the invention provides a polymer overmolded wheel-balancing weight having a shape adapted to substantially match the circumference of the wheel secured thereto. 
     At least one embodiment of the invention provides an overmolded wheel-balancing weight wherein the weight is secured to the wheel-securing clip on the side opposed to the wheel-side when the overmolded wheel-balancing weight is secured to a wheel. 
     At least one embodiment of the invention provides an overmolded wheel-balancing weight that connects the weight to the wheel-securing clip via a protrusion formed in the weight; the protrusion being adapted to be compressed and/or riveted to secure the wheel-securing clip therewith. 
     At least one embodiment of the invention provides a wheel-securing clip for securing an overmolded wheel-balancing weight to a wheel that includes a recessed weight-securing portion sized and designed to receive therein material from a compressed protrusion protruding from the weight. 
     At least one embodiment of the invention provides a method of manufacturing an overmolded wheel-balancing weight, wherein the wheel-securing clip is used to locate the wheel-balancing weight in the mold; the wheel-balancing weight being preferably secured on the fixed portion of the mold. 
     At least one embodiment of the invention provides a method of manufacturing an overmolded wheel-balancing weight, wherein the wheel-balancing weight is secured in the mold with a clip-securing member adapted to pull the wheel-balancing weight with a moveable side of the mold. 
     At least one embodiment of the invention provides a method of manufacturing an overmolded wheel-balancing weight, wherein the overmolding material and/or the wheel-balancing weight is preheated to prevent expedite solidification of the injected overmolding material. 
     At least one embodiment of the invention provides a method of manufacturing an overmolded wheel-balancing weight, wherein the overmolding material is injected nearby the wheel-securing clip to equally distribute the overmolding material in the injection cavity of the injection mold. 
     At least one embodiment of the invention provides a colored polymer overmolded wheel-balancing weight adapted to substantially match the color of the wheel it is secured to. 
     At least one embodiment of the invention provides a kit of colored overmolded wheel-balancing weights wherein colors are adapted to distinguish wheel-balancing weights different having different weights. 
     At least one embodiment of the invention provides an injection mold including at least one retractable stem therein adapted to locate the weight in the injection mold during the injection of the overmolding material in the injection chamber, the at least one retractable stem being further adapted to be retractable during the injection process to allow complete overmolding of the weight, the at least one retractable stem also being adapted to be extended to locate and eject the overmolded wheel-balancing weight from the injection mold. 
     At least one embodiment of the invention provides a polymer (or plastic) weight (e.g. steel less weight) supported by a wheel-securing clip, the polymer weight being molded with the wheel-securing weight, the polymer weight being desirable for lightweight wheel-balancing masses that do not require a metallic weight. 
     At least one embodiment of the invention provides an overmolded wheel-balancing weight comprising a wheel-securing clip adapted to be secured to a wheel, a weight assembled to the wheel-securing clip and overmolding material adapted to at least partially cover the weight to protect the weight, wherein at least a portion of the wheel-securing clip is an overmolding material boundary. 
     At least one embodiment of the invention provides a method of manufacturing an overmolded wheel-balancing weight, the method comprising opening an injection cavity of an injection mold; securing the wheel-securing clip to a clip-supporting member in the mold to locate a weight in the injection cavity; closing the injection mold with a weight in the injection cavity; injecting overmolding material in the injection cavity to overmold at least a portion of the weight; opening the mold; and extracting the overmolded wheel-balancing weight from the mold. 
     At least one embodiment of the invention provides a plastic wheel-balancing weight adapted to be removably secured to a wheel to correct an unbalanced wheel to prevent undesired vibrations when the wheel is rotating, the plastic wheel-balancing weight comprising a wheel-securing clip sized and designed to be resiliently secured to a wheel; and a steel weight assembled to the wheel-securing clip and at least partially covered with plastic, at least a portion of the plastic being shaped by the wheel-securing clip. 
     Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     Additional and/or alternative advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, disclose preferred embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings which form a part of this original disclosure: 
         FIG. 1  is a top plan view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 2  is a flow chart illustrating a series of steps to produce an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 3  is a flow chart illustrating a series of steps to produce an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 4  is an almost front elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 5  is a front elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 6  is a top plan view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 7  is a rear sectional elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 8  is a front sectional elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 9  is a transversal isometric sectional elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 10  is a transversal sectional elevational view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 11  is an isometric view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 12  is a transversal sectional view of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 13  is an isometric view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 14  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 15  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 16  is left side elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 17  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 18  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 19  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 20  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 21  is a transversal sectional elevational view of a wheel-securing clip in accordance with at least one embodiment of the invention; 
         FIG. 22  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 23  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 24  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 25  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 26  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 27  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 28  is a transversal sectional elevational view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 29  is an isometric view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 30  is an isometric view of a wheel-securing clip and a weight of an overmolded wheel-balancing weight in accordance with at least one embodiment of the invention; 
         FIG. 31  is an isometric view of a portion of an injection mold in accordance with at least one embodiment of the invention; 
         FIG. 32  is a side elevation view of a portion of an injection mold in accordance with at least one embodiment of the invention; 
         FIG. 33  is an isometric view of a portion of an injection mold in accordance with at least one embodiment of the invention; 
         FIG. 34  is an illustrative flow chart of an exemplary series of steps in accordance with at least one embodiment of the invention; and 
         FIG. 35  is an illustrative flow chart of an exemplary series of steps in accordance with at least one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the present invention are described bellow with reference to the appended Figures. An exemplary overmolded metallic wheel-balancing weight  10  is illustrated in  FIG. 1 . The wheel-balancing weight  10  defines, for the purpose of the following description, at least two illustrative plans thereof. A longitudinal plan  14  disposed along the longitudinal direction of the wheel-balancing weight  10  and a transversal plan  18  orthogonally intersecting the longitudinal direction of the wheel-balancing weight  10 . It is understood that the present invention can be completely or partially applied to a variety of wheel-balancing weights  10  having various sizes and shapes. 
     The illustrative wheel-balancing weight  10  depicted in  FIG. 1  is overmolded with an polymer overmolding material such as polyethylene and polypropylene. The overmolding material  22  overmolds and protects the steel weight  26  therein against, inter alia, water, corrosion, dust and other debris encountered on the road. The overmolding material also servers to protect the wheel form the wheel-balancing weight  10  during installation on the wheel and when the wheel-balancing weight  10  is installed on the wheel under normal road use. Additionally, the overmolding material is used to improve the aesthetic appearance of the wheel-balancing weight and be used to visually differentiate different weights. 
     A wheel-securing clip  30  is secured to the overmolded steel weight  26  to removably secure the wheel-balancing weight  10  to the periphery of a wheel (not shown). An optional hole  34  is performed in the wheel-securing clip  30  in some embodiments to adjust the clipping force of the wheel-securing clip  30  on the wheel, provide a grip to remove the wheel-balancing weight  10  from the wheel and/or reduce the weight of the wheel-balancing weight  10 . The hole  34  is also used in some embodiments of the manufacturing process to handle the wheel-balancing weight  10  as it is going to be further explained below. Radiuses  38 , or chamfers  38 , are provided on ends corners of the wheel-securing clip  30  to prevent creating stress concentrators in the overmolded polymer that could result in rupturing the overmolded polymer and create cracks therein. The radiuses  38 , or chamfers  38  also help prevent damaging the wheel with sharp edges if used without overmolding. Embodiments of the present invention includes a reduced thickness portion  42  of the overmolded material  22 , in the neighborhood of the wheel-securing clip  30 , to prevent interferences between the overmolding material  22  and the wheel-securing clip  30 . The portion  42  thus facilitate proper connection between the wheel-securing clip  30  and the wheel and prevents any overmolding material  22  to be injected within the cavity defined by the wheel-securing clip  30  that would render harder the ejection of the wheel-balancing weight  10  from the mold. We will return later to the manufacturing aspects of the wheel-balancing weight  10  after some details concerning process embodiments for manufacturing the wheel-balancing weight  10 . 
       FIG. 2  illustrates an exemplary series of manufacturing steps adapted to produce a wheel-balancing weight  10 . An unmolded steel weight  26  is provided from raw material, preferably in the shape of a steel rod  50 , a steel wire  50 , or similar monolithic steel weight  26  adapted to improve wheel balancing. The raw steel rod is cut  54  and the length of the cut portion of steel rod  50  is determined by the desired weight of the wheel-balancing weight  10 . The total mass of the wheel-balancing weight  10  is equal to the added weight of the wheel-securing clip  30 , the steel weight  26  and the overmolding material  22 . The longer the portion of cut steel rod  50  is, the heavier the wheel-balancing weight  10  is going to be. Chamfers or radiuses are optionally performed  58  on each end of the steel weight  26  to remove undesirable sharp edges. The steel weight  26  is then stamped  62  to create therein a fastening protrusion  128  and an optional opposed compressed portion  140  that will be described in details below. The steel weight  26  is optionally plated after it has been chamfered and/or bent to improve, inter alia, its corrosion resistance  66 . A wheel-securing clip  30  is assembled  70  with the corresponding fastening protrusion and the wheel-securing clip  30  is secured to the steel weight  26  by compressing and deforming the fastening protrusion  74  to secure the wheel-securing clip  30  to the steel weight  26 . The assembled wheel-balancing weight  10  is then bent  78  to match the radius of the wheel it is going to be assembled to. The steps above are for illustrative purposes and can be reordered without departing from the scope of the present application. 
       FIG. 3  illustrates another exemplary series of steps for manufacturing polymer-overmolded wheel-balancing weights  10  in accordance with embodiments of the invention. An unmolded wheel-securing clip  30  and steel weight  26  assembly is inserted in an injection mold  90 . The mold is closed  94  to define a volume therein (e.g. injection chamber) for injecting a polymer, a resin, a thermoset plastic, a plastic or another suitable overmolding material around the unmolded wheel-securing clip  30  and steel weight  26  assembly. The connection between the wheel-securing clip  30  and the mold could be used to locate the steel weight  26  inside the mold. Polymers, such as polypropylene and polyethylene, could be used in the process. A precise fit is provided between the mold and the wheel-securing clip  30  to prevent any injection of plastic at undesired locations around the wheel-securing clip  30 . The mold interface with the wheel-securing clip  30  is designed in embodiments of the invention to prevent any undercuts that would interfere with the ejection of the molded wheel-balancing weight  10  with a mold having two halves and a single longitudinal parting line. Polymer is injected  98  in the mold and the injected plastic is cooled  102  prior to opening the mold  106  and extracting  110  the overmolded wheel-balancing weight from the mold. 
       FIG. 4  through  FIG. 10  refer to an exemplary embodiment of the invention. More precisely  FIG. 4  through  FIG. 6  depict the exterior of the wheel-balancing weight  10  where it is possible to see the polymer overmolding  22 , the parting line  120 , and the wheel-securing clip  30  extending outside the polymer overmolding  22 . 
       FIG. 7  and  FIG. 8  respectively illustrate longitudinal sectional views of the wheel-balancing weight  10  where one can appreciate a compressed portion  124  in the steel weight  26  from which extends the fastening protrusion  128 . The fastening protrusion  128  is assembled with a corresponding opening  132  located in the clip  30 . The illustrated assembly secures the wheel-securing clip  30  with the steel weight  26  by bending or compressing the fastening protrusion  128  when the wheel-securing clip  30  is assembled thereto. It can also be appreciated from these Figures that the steel weight  26  of the wheel-balancing weight  10  is curved along a radius  136 . The optional opposite compressed portion  140  can be appreciated on the other side of the steel weight  26  illustrated in  FIG. 8 . The opposite compressed portion  140  helps to ensure proper pressure is put on the steel weight  26  at the stamping phase to create the fastening protrusion and also increases the strength of the steel weight  26  by locally hardening the material. The material of the protrusion  128  is adapted to be housed by a recessed portion  188  of the wheel-securing clip  30  that will be detailed later below. 
     Turning now to  FIG. 9  where the fastening protrusion  128  assembly with the corresponding opening  132  located in the clip  30  is illustrated with more details. From this figure it can be appreciated that the mold (visible schematically illustrated in  FIG. 10 ) design circumscribes the clip  30  and that results in no plastic injection within the clip  30  cavity  144 . Further, the shape of the clip  30  defines a radius  148  that retains the injected plastic on its proximal side  156  when the plastic is injected and abuts the plastic portion of the wheel-balancing weight  10  when the wheel-balancing weight  10  is overmolded. This layout allows overmolding the fastening protrusion  128  and the assembly with the clip  30  with plastic thus improving its corrosion resistance while reducing the risk of damaging the wheel when the wheel-balancing weight  10  is assembled to the wheel.  FIG. 10  illustrates an exemplary mold having two halves  160 ,  164  circumventing the wheel-securing clip  30  while defining a closed volume around the steel weight  26  to receive injected plastic therein. It can be appreciated that the shape of the mold&#39;s halves  160 ,  164  is adapted to use the wheel-securing clip  30  as a mold boundary and thus prevent plastic to be injected too far within the cavity defined by the clip  30 . This is one way to ensure there is no undercut in the molding that would prevent extraction of the molded part  10  from a mold having two halves  160 ,  164  and opening in the longitudinal plan  14  of the wheel-balancing weight  10 . In an alternate embodiment, the clip  30  can be completely free of plastic. Plastic is injected all around the clip  30  and even leaves the region of the clip that is connected with steel weight  26  free of plastic. Conversely, it could be advantageous to cover the connecting region between the clip  30  and the steel weight  26  with plastic to further prevent corrosion. 
     Moving now to  FIG. 11  and  FIG. 12  illustrating another embodiment of the invention. One can appreciate from  FIG. 11  that the clip  30  has a different radius  148  causing the clip  30  to protrude almost perpendicular from the plastic molding  22 . As best seen in  FIG. 12 , the present assembly allows sufficient distance  152  between the clip  30  and the polymer overmolding  22  to insert therein a portion of the mold adapted to mate with the clip  30  and prevent plastic injection around the clip  30  that would prevent a two halves  160 ,  164  mold to be opened in the longitudinal plane  14  and the wheel-balancing weight  10  to be easily extracted from the mold. In the present situation, a schematic two-halves  160 ,  164  mold with a single longitudinal opening therein has been drafted showing that the wheel-balancing weight  10  can be ejected from the mold that opens in two according to arrows  170 . 
       FIG. 13  illustrates a wheel-securing clip  30  equipped with a barb  174  adapted to further secure the wheel-securing clip  30  to a wheel by providing additional gripping to the wheel. The barb  174  of the present embodiment provides a second spring clamping  180  for gripping the wheel in addition to the first spring clamping  184  provided by the main body of the wheel-securing clip  30 . The shape of the wheel-securing clip  30  is adapted to engage the side of a wheel and is also adapted to be secured to the steel weight  26 . The interface between the wheel-securing clip  30  and the steel weight  26  has generally been described above. The wheel-securing clip  30  illustrated in  FIG. 13  is provided with a recessed portion  188  sized and designed to receive therein material from the compressed fastening protrusion  128  (not illustrated in  FIG. 13 ) engaging the opening  132  in the wheel-securing clip  30 . The opening  132  can be round or have a different shape adapted to prevent relative rotation of the two parts. The recessed portion  188  would preferably be deep enough to receive therein the material from the compressed fastening protrusion  128  so that it does not extend above the surrounding surface  192 . This helps reduce the required thickness of overmolding material  22  (not illustrated on  FIG. 13 ) over the “riveted” assembly of the wheel-securing clip  30  and the steel weight  26 . 
     Another aspect of the wheel-securing clip  30  illustrated in  FIG. 13  is the recessed position of the surface  192  provided by a projecting portion  196  included in the design of the wheel-securing clip  30 . The projecting portion  196  is embodied as a curved portion  200  in the present example. The curved portion  200  defined in the wheel-securing clip  30  locate the surface  192  deeper so that the overmolding material  22  can meet the curved portion  200  in a way to produce an efficient junction. This can be better understood by comparing a wheel-securing clip  30  having no projecting portion  196 , in  FIG. 14 , and the wheel-securing clip  30  of  FIG. 13  illustrated from the side in  FIG. 15 . One can appreciate that the curved portion  200  provides a junction area  204  adapted to abut the overmolding material  22  that is schematically represented in  FIG. 15 . The junction area  204  created by the curved portion  200  defined in the projecting portion  196  is adapted to abut the overmolding material  22 . The curved portion  200  can be used as an extension of the mold and is used to further define the volume defined by the mold. The curved portion  200  provides a more “radial” junction surface with the overmolding material  22 . This prevents having a very thin layer of overmolding material  22  joining the wheel-securing clip  30  that could easily wave or curve and leaves an opening for dirt and water to enter between the overmolding material  22  and the wheel-securing clip  30 . In some embodiments, the desired thickness  208  of overmolding material  22  over the surrounding surface  192  can dictate the height of the curved portion  200  therefore many different designs are possible to serve different needs. A second junction area  212  is provided on the opposite side and preferably provides a surface that can substantially radially abuts the overmolding material  22 . As it can be appreciated, a whole portion  216  of the wheel-securing clip  30  is used to contain the overmolding material  22 . 
       FIG. 16  through  FIG. 21  illustrate a series of embodiments including wheel-securing clips  30  having different shapes adapted to be secured to different shape of wheels and adapted to cooperate with various metallic weights  26 . For example, the embodiments illustrated in  FIG. 13 ,  FIG. 15 ,  FIG. 17 ,  FIG. 18  and  FIG. 20  respectively have a flat clip portion  220 .  FIG. 19  illustrates an embodiment including an angled flat clip portion  224 . 
     Turning now to  FIG. 22  through  FIG. 25  illustrating a series of sectional embodied wheel-balancing weights  10 . In these embodiments the steel weight  26  is assembled to the wheel-securing clip  30  but the fastening protrusion  128  is not shown compressed. From these embodiments one can appreciate the distribution of the overmolding material  22  over the steel weight  26 . The contact locations  230  between the steel weight  26  and the wheel-securing clip  30  is clearly shown for each embodiment.  FIG. 22  illustrate en embodiment corresponding to the wheel-securing clip  30  of  FIG. 14  that does not include a deporting portion  196 . The embodiments shown in  FIG. 15  through  FIG. 27  include the deporting portion  196  that allows an additional thickness  208  of overmolding material  22 . It can be appreciated from  FIG. 23  through  FIG. 27  that the combination of the deporting portion  196  and the recessed portion  188  of the wheel-securing clip  30  create a sequence of three combined curves  234  (or combined angled portions). A portion of a stamping  46 , or a shape/letters/information, defined in the overmolding material  22  can also be seen in these figures. 
     Referring to  FIG. 22 , the steel weight  26  is provided with flat, or planar, contact portions  238  adapted to provide a suitable contact interface with the wheel-securing clip  30 . Radiuses  242  are provided on the metallic weights  26  to substantially match the curvature of the clip  148  in some embodiments and also provide a space where overmolding material  22  can be injected between the wheel-securing clip  30  and the metallic-weight  26 . 
     The wheel-securing clip  30  is secured to the steel weight  26  via the interface provided between the fastening protrusion  128  engagement with the opening  132  provided in the wheel-securing clip  30 . The fastening protrusion  126  is compressed  250  to protrude and extend  254  over the recessed portion  188  of the wheel-securing clip  30  as it can be appreciated in  FIG. 28 ,  FIG. 29  and  FIG. 30 . This assembly ensures that the wheel-securing clip  30  is permanently secured to the steel weight  26  to create a unitary wheel-balancing weight  10 . 
     The overmolded-wheel balancing weight  10  of embodiments of the invention is manufactured with an injection process. The injection process uses a mold  270  including a fixed portion  274  and a movable portion  278  that can be appreciated in  FIG. 31  through  FIG. 33 . The wheel-securing clip  30  and steel weight  26  assembly is positioned in the mold  270  prior to injecting the polymer in the mold  270 . The wheel-securing clip  30  and steel weight  26  assembly is located in the mold  270  by hooking the wheel-securing clip  30  to a clip supporting member  282  when the mold  270  is open. The wheel-securing clip  30  is preferably self-positioned by contacting the clip supporting member  282  at a plurality of locations. In the embodiment exemplified in  FIG. 32 , the end  286  of the wheel-securing clip  30  contacts the upper side  290  of the clip supporting member  282  while a lower portion  216  of the wheel-securing clip  30  contacts the lower side  294  of the clip supporting member  282 . Further, the end  286  of the wheel-securing clip  30  is contacting a vertical edge  298  of the mold  270  to ensure not lateral movement is allowed. The clip-supporting member  282  of the illustrated embodiment is defined in the fixed portion  274  of the mold  270  with a clip-receiving cavity  302  included in the mold  270 . The clip-receiving cavity  302  is prolonging a clip-retaining member cavity  306  in the movable portion  278  of the mold  270  from which extends a movable clip-retaining member  310  that will be discussed below in details. 
     The wheel-securing clip  30  is temporarily secured in the mold  270  when the movable portion  278  of the mold  270  is closed onto the fixed portion  274  by applying a pressure on the wheel-securing clip  30  with a clip mating edge  314 . With that configuration, the wheel-securing clip  30  and steel weight  26  assembly is positioned such that the wheel-securing clip  30  is firmly secured in the closed mold  270  and the steel weight  26  is suspended in the injection cavity  318  of the mold  270 . Injection of the overmolded material is preferably made symmetrically in the injection cavity  318 . In the illustrated embodiment, the injection is made through a central injection port  322  to ensure equal distribution of the injection material  22  in the injection cavity  318 . Alternatively, the injection could be made by a plurality of injection ports (not illustrated) that would also equally distribute the injection material  22  in the injection cavity  318 . The steel weight  26  can be preheated prior to be placed in the injection cavity  318  to help prevent expedited solidification of the injection material  22  by cooling too fast the injection material  22  in the mold  270  such that the injection material  22  doesn&#39;t have time to fill completely the injection cavity  318  before solidification. Another way to help prevent early solidification of the injection material  22  is to preheat the injection material  22  in the circuit bringing the injection material  22  in the mold  270  to increase the time before the injection material  22  begins solidification. Positioning stems  338  (visible in  FIG. 33 ) are provided in the mold  270  to help locate properly the steel weight  26  in the injection cavity  318 . These positioning stems  338  are adapted to be axially movable for contacting the metallic weight  22  when the mold  270  is closed and ensure proper positioning of the metallic weight  22 . The positioning stems  338  are adapted to be retracted as some point during the injection process when the overmolding material  22  begins to flow in the injection cavity  318 . The positioning stems  338  becomes optional when the overmolding material  22  is injected in the injection cavity  318  because the overmolding material  22  stabilizes the steel weight  26  in the injection cavity  318 . The injection of the overmolding material  22  is completed when the positioning stems  338  are retracted to ensure an even finish of the overmolding material  22 . The stems  338  are extended again, in an embodiment of the invention, when the mold  270  opens to stabilize and eject the overmolded wheel-balancing weight  10  from the mold  270 . 
     The movable clip-retaining member  310  is engaging the hole  34  included on the upper side of the wheel-securing clip  30  when the mold  270  is closing. The movable clip-retaining member  310  extends from the clip-retaining cavity  306  in the movable portion  278  of the mold  270 . The clip-retaining cavity  306  is sized and designed to allow sufficient vertical movements  326  to allow engagement of the hook  330  with the hole  34 . A corresponding opening  334  is included in the fixed portion  274  of the mold  270 . The corresponding opening  334  is configured to receive therein the movable clip-retaining member  310  and also to push the movable clip-retaining member  310  downward so that the hook  330  engages in the hole  34  of the wheel-securing clip  30  and cannot disengage when the mold  270  is closed. The movable clip-retaining member  310  is used to pull the overmolded wheel-balancing weight  10  from the fixed portion  274  of the mold  270  as it can be seen in  FIG. 33 . Once the overmolded wheel-balancing weight  10  pulled from the fixed portion  274  of the mold  270  the movable clip-retaining member  310  is moved upward to disengage the movable clip-retaining member  310  from the hole  34  of the wheel-securing clip  30 . 
     Referring now more precisely to  FIG. 33 , the illustrated overmolded wheel-balancing weight  10  has no overmolding material  22  in the neighborhood of the wheel-securing clip  30  to better see the assembled overmolded wheel-balancing weight  10  and also to illustrate one embodiment of the invention. In contrast, the junction of the wheel-securing clip  30  with the steel weight  26  is covered in other embodiments discussed above. 
       FIG. 34  illustrates an exemplary sequence of steps that can be used to overmold a wheel-balancing weight  10 . The mold  270  opens  350 , the steel weight  26  is heated  354  to prevent early solidification of the overmolding material  22 , The wheel-securing clip  30  is secured  358  in the mold  270 , the mold is closed  362  and the wheel-securing clip  30  is secured in the mold  270 , the polymer, or the overmolding material, is heated  366  prior to be injected in the mold  270 , the polymer is injected  370  in the mold  270  and solidifies, the mold  270  opens  374  to extract the overmolded wheel-balancing weight  10  therefrom  374 , the hook  330  from the movable clip-retaining member  310  is released  378  from the wheel-securing clip  30  and finally the overmolded wheel-balancing weight  10  is released  382  from the mold  270 . 
     Similarly,  FIG. 35  illustrates another alternate sequence of steps adapted to embody embodiments of the invention. The wheel-securing clip  30  is used to locate  390  the unmolded steel weight  26  in the mold  270 , The mold  270  is closed and the hook  330  engages  394  the wheel-securing clip  30 , the overmolding material is heated  398  prior to being injected in the mold  270 , the overmolding material  22  is injected in the mold&#39;s injection cavity  318 , the locating stems  338  are retracted  406  during injection of the overmolding material  22  in the injection cavity  318 , the injection stops  410 , the mold  270  opens  414  and the overmolded wheel-balancing weight  10  is extracted  418  from the mold  270 . 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments and elements, but, to the contrary, is intended to cover various modifications, combinations of features, equivalent arrangements, and equivalent elements included within the spirit and scope of the appended claims. Furthermore, the dimensions of limiting, and the size of the components therein can vary from the size that may be portrayed in the figures herein. Thus, it is intended that the present invention covers the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.

Technology Classification (CPC): 1