Abstract:
An apparatus for supporting a tube during plastic injection overmolding, the apparatus comprising at least one rod adapted to support essentially the entirety of an inner surface of a tube during at least a part of a plastic injection overmolding process for coating at least a portion of an outer surface of the tube.

Description:
FIELD 
       [0001]    The disclosure relates to structurally reinforced, molded plastic parts. 
       BACKGROUND 
       [0002]    Injection overmolding generally comprises coating a substrate placed inside a mold with a liquid, powder and/or slurry plastic (hereinafter referred to as “molten plastic”) at relatively high temperatures. The molten plastic is usually injected into the mold at high pressures or at low pressures, depending on the application and the type of substrate. Low pressure injection overmolding is typically done with injection pressures ranging from 10-40 MPa (100-400 bar), while high pressure injection overmolding is typically done with injection pressures ranging from 80-200 MPa (800-2000 bar). Generally, for structurally reinforced, molded plastic parts, the substrate may comprise a tube, a profile, or some other shaped, rigid element adapted to resist the high temperatures and pressures associated with injection overmolding. 
         [0003]    There are advantages to using high pressure injection overmolding in the fabrication of structurally reinforced, molded plastic parts. For example, moduli of elasticity, impact resistance, puncture resistance, and other mechanical characteristics, are substantially improved in reinforced parts produced by high pressure injection overmolding compared with parts produced by low pressure injection overmolding. Additionally, thickness of a plastic coating may be substantially reduced when using high-pressure injection overmolding, providing for a relative saving in manufacturing costs while also maintaining anticorrosion characteristics. 
         [0004]    Generally, substrate design requirements include a use of profiles which are rigid, lightweight, and fabricated from relatively inexpensive materials. Furthermore, the profiles are generally required to be of sufficient strength to not deform and/or suffer other mechanical degradations, as a result of a force with which the molten plastic strikes the profiles when injected into the mold at high pressure. Usually, in order to prevent deformations and/or other mechanical degradations, profiles with relatively thick walls, for example. greater than 3 mm are typically used. The use of profiles with relatively thick walls is generally a problem as the profiles may have a tendency to be relatively heavy in weight. 
         [0005]    US Patent Application Publication No. 2007/0071929 A1, “Molded Article with Metal Reinforcing and Method for its Manufacture”, incorporated herein by reference, describes “a composite article comprises a channel-shaped metal reinforcing element and molded plastic shell including a portion formed as a wall mechanically closing the open side of the channel shape. The reinforcing element may include a plurality of open channels each of them being closed by a portion of the plastic coating. Constructive elements comprising at least two such composite articles may be manufactured, for example a flat panel made of parallel elongated beams. A method for manufacturing the composite article in an assembly mold includes inserting a mold core in the metal reinforcing element via the open side of the channel transversely to the channel axis, assembling all parts of the mold, molding of the plastic coating, disassembling the mold; and removing the mold core from the composite article in direction parallel to the channel axis.” 
         [0006]    European Patent Application EP 1238773 A1, “System for Overmolding Tubes in Plastic Parts”, incorporated herein by reference, describes a “system for overmoulding tubes in plastic parts, in which a tube, generally metallic and thin, is housed in the interior or a mould for its overmoulding, in that the tube is arranged on the supports in the said interior of the mould ins in that the filling is carried out with the plastic material in order to obtain a plastic structure in which the tube is fastened to the said structure, with the interior of the tube being completely free of any plastic material at the end of the overmoulding due to its being closed during the process, which is characterized in that while the overmoulding of the tube is taking place, means are provided in the interior of the tube to keep the shape of the tube unalterable by withstanding the external pressure exerted by the plastic material, with the application of these means being maintained until the part has been cooled and then proceeding to remove them once the part has been finished.” 
         [0007]    Japanese Patent Publication No. 63141713 A, “Suction Pipe Made of Synthetic Resin for Engine and its Manufacture”, incorporated herein by reference, describes a method “to enable the suction path having two dimensional or mote complicated shape which is not capable of molding by injection molding to be achieved, while enabling ensuring the shape and the surface accuracy of a flange part which is not capable of molding by flow molding to be achieved by means of using the core in which the blow molding becoming the suction path of inner layer after molding is filled with sand, etc.” A drawback with the method described may be the possible combining of sand with the melted plastic, which may affect the surface finish of the reinforced part. To avoid this, tight production controls may be required, possibly resulting in increased production costs and production time. 
       SUMMARY 
       [0008]    An aspect of some embodiments of the disclosure relates to providing a system and method for high pressure injection overmolding of relatively thin-walled rigid substrates. 
         [0009]    According to an aspect of some embodiments of the disclosure, a structural insert (rod) is slidingly inserted inside a closed, or essentially closed, profile (tube) placed inside a high pressure injection mold, the structural insert adapted to distribute pressure (forces) acting on profile walls during high pressure injection overmolding, over the whole of, or optionally a portion of, the insert, such that deformation of the profile is substantially prevented. A deformation amplitude in the profile due to the injection pressure is maintained to a maximum of about 1 mm, substantially in the order of magnitude of a clearance between the insert and the profile, which may generally range from 0.05 mm-1 mm, and substantially less than that achieved through other methods known in the art. This allows for a better finished product, for example, in applications where an object may be inserted in the profile. For example, a connector to be inserted at ends of profiles which are to be joined together may be inserted with ease as the deformations in the profiles are relatively small and do not interfere with the insertion. The relatively small clearance substantially prevents molten plastic from flowing into the space between the insert and the profile, which and may warp the profile walls. 
         [0010]    According to an aspect of some embodiments of the disclosure, the use of a structural insert, adapted to exert an equal and opposing pressure to that resulting from the injection overmolding, substantially allows for the use of substantially thin-walled closed, or essentially closed, profiles. For example, profile wall thickness may be 0.1 mm or greater. Profiles of wall thickness between 0.1-1 mm are generally readily available in markets, and relatively easy to obtain. Additionally, the use of thin-walled closed profiles allow for the manufacture of lighter-weight products. 
         [0011]    The profile may be a rigid closed, or essentially closed, metal tube, and may comprise a cross-section of substantially any geometrical shape, such as, for example, circular, elliptical, quadrilateral, pentagonal, hexagonal, heptagonal, octagonal, or other polygonal shape with more than eight sides, or any combination thereof. The structural insert may be fabricated from any material adapted to resist temperatures of, for example, 230-250 degrees Celsius, and up to approximately 300 degrees Celsius, typically associated with high pressure injection overmolding processes. Examples of some materials adapted to resist the high temperatures may be metal, metal alloys, ceramic, composites, and others. Furthermore, the structural insert may comprise a solid cross-sectional shape substantially similar to an inner cross-section of the profile, and which may be referred to hereinafter as a “solid insert”. Optionally, the insert may comprise a non-solid cross-sectional shape, and which may be referred to hereinafter as a “non-solid insert”. Additionally or alternatively, the structural insert may comprise a cross-sectional shape different than the inner cross-section of the profile, and which may be referred to hereinafter as an “irregular insert”. 
         [0012]    In accordance with an embodiment of the disclosure, the structural insert may be slidingly inserted through a first opening at one end of the profile along a whole length of the profile. Optionally, the structural insert may be inserted through the first opening, and a second structural insert may be inserted through a second opening at an opposing end of the profile, each structural insert extending only a portion of the length of the profile until they abut one another. The structural insert may comprise a carrier at one end adapted to drive the structural insert into the profile, and further adapted to pull the structural insert out of the profile after the injection overmolding is completed. 
         [0013]    The profile is supported along an underside by supports which are removed when the overmolding material, which may be a plastic, partially, or wholly, covers the underside and exerts enough pressure on the profile to maintain a separation between the profile and the mold. Optionally, the supports are not removed so as to substantially prevent possible recesses in the molded plastic coating, which may expose the profile, in locations where the supports were used. 
         [0014]    In accordance with an embodiment of the disclosure, the mold is adapted to restrain the plastic coated tube so as to allow the insert to be pulled out of the tube once the overmolding process is completed. The mold comprises a step into which a section of a perimeter at each end of the coated tube fits. A height of the step may be approximately equal to a thickness of the plastic coating and the profile wall thickness, or optionally less. When the insert is to be pulled out of the tube, the step acts as a barrier by pushing on the section of the perimeter at the tube end, and does not interfere with the insert removal. Optionally, the mold comprises a step for a section of the perimeter at one end of the tube. 
         [0015]    In some embodiments of the disclosure, the structural insert may be fabricated from a material with a coefficient of thermal expansion greater than that of the profile. Once inserted into the profile, the hot temperatures of the molten plastic cause the insert to expand more than the profile, closing a relatively small clearance between the insert and the profile. Following injection of the molten plastic, the insert and profile are allowed to cool down, the insert contracting more than the profile to allow a relatively small clearance to develop. The insert may then be withdrawn. The relatively small clearance may be in the range from 0.05 mm-1 mm, for example 0.1 mm, depending on the material characteristics of the insert and the profile, and is adapted to allow the insert to be slidingly inserted and withdrawn. 
         [0016]    There is provided, in accordance with an embodiment of the disclosure, a method for overmolding, comprising supporting essentially the entirety of an inner surface of a tube to be coated; and coating at least a portion of an outer surface of the tube by plastic injection overmolding. Optionally, overmolding comprises high pressure injection overmolding. Optionally, the method further comprises distributing forces exerted on the tube. 
         [0017]    In some embodiments of the disclosure, supporting essentially the entirety of an inner surface of a tube to be coated, comprises supporting the tube by inserting at least one rod into said tube. Optionally, two rods are inserted into the tube. Optionally, a clearance between the at least one rod and the tube is less than 1 mm. Additionally or alternatively, the at least one rod is inserted through either end of the tube. Optionally, a first rod is inserted through one end of the tube, and a second rod is inserted through the other end of the tube. 
         [0018]    In some embodiments of the disclosure, high pressure injection overmolding comprises injecting molten plastic at a pressure of 80-250 MPa. Optionally, molten plastic is injected at a pressure of 80-120 MPa. Optionally, molten plastic is injected at a pressure of 120-180 MPa. Optionally, molten plastic is injected at a pressure of 180-250 MPa. 
         [0019]    In some embodiments of the disclosure, the method further comprises removing the rod from the tube following a cooling down period. Optionally, the cooling down period is 5 seconds or less. 
         [0020]    There is provided in accordance with an embodiment of the disclosure, an apparatus for supporting a tube during plastic injection overmolding, the apparatus comprising at least one rod adapted to support essentially the entirety of an inner surface of a tube during at least a part of a plastic injection overmolding process for coating at least a portion of an outer surface of the tube. Optionally, the plastic injection overmolding process comprises high pressure injection overmolding. Optionally, the rod is adapted to distribute forces exerted on the tube. 
         [0021]    In some embodiments of the disclosure, the at least one rod comprises two rods. Optionally, a clearance between the at least one rod and the tube is less than 1 mm. Optionally, a clearance between the at least one rod and the tube is less than 0.5 mm. Additionally or alternatively, a clearance between the at least one rod and the tube is less than 0.1 mm. 
         [0022]    In some embodiments of the disclosure, the at least one rod is inserted into the tube from either end. Optionally, a first rod is inserted into the tube through one end of the tube and a second rod is inserted into the tube through the opposite end of the tube. 
         [0023]    In some embodiments of the disclosure, molten plastic is injected at a pressure of 80-250 MPa. Optionally, molten plastic is injected at a pressure of 80-120 MPa. Optionally, molten plastic is injected at a pressure of 120-180 MPa. Optionally, molten plastic is injected at a pressure of 180-250 MPa. 
         [0024]    In some embodiments of the disclosure, the at least one rod is removed from the tube following a cooling down period. Optionally, the cooling down period is 5 seconds or less. 
         [0025]    In some embodiments of the disclosure, the rod is a rigid metal tube. Optionally, the rod comprises a circular, elliptical, quadrilateral, pentagonal, hexagonal, octagonal or other polygonal cross-section. Additionally or alternatively, the rod is solid tube. Optionally, the rod is adapted to resist temperatures up to about 300 degrees Celsius. 
         [0026]    There is provided, in accordance with an embodiment of the disclosure, a system for facilitating plastic injection overmolding, the system comprising a rod adapted to support essentially the entirety of an inner surface of a tube during at least one stage of a plastic injection overmoulding process for coating at least a portion of an outer surface of the tube; and a carrier unit adapted to insert said rod into the tube and to remove said rod from the tube upon completion of the at least one stage of a plastic injection overmoulding process. 
         [0027]    There is provided, in accordance with an embodiment of the disclosure, a plastic coated tube produced by a high pressure injection overmolding process comprising a metal profile of minimum wall thickness 0.1 mm; and a deformation amplitude in the profile of 1 mm or less. 
         [0028]    There is provided, in accordance with an embodiment of the disclosure, an article of manufacture comprising plastic coated tubes produced by a high pressure injection molding process, wherein each tube comprises a metal profile of minimum wall thickness 0.1 mm and a deformation amplitude of 1 mm or less. Optionally, the article of manufacture is a storage shack. Optionally, the article of manufacture is a chair. Optionally, the article of manufacture is a table. Optionally, the article of manufacture is a building panel. Optionally, the article of manufacture is a window. Optionally, the article of manufacture is a door. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0029]    Examples illustrative of embodiments of the disclosure are described below with reference to figures attached hereto. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. 
           [0030]      FIGS. 1A and 1B  schematically show a top view and a side view, respectively, of an exemplary high pressure injection overmolding system, in accordance with an embodiment of the disclosure; 
           [0031]      FIGS. 1C ,  1 D, and  1 D′ schematically show cross-sectional views A-A, B-B (inner cross section), and C-C, respectively, of the system of  FIG. 1A  comprising a round profile and a solid insert, in accordance with an embodiment of the disclosure; 
           [0032]      FIGS. 1E and 1F  schematically show a sectional side view and a cross-sectional view D-D of the profile of  FIG. 1C , respectively, comprising insufficient interior reinforcement during a high pressure injection molding process, as known in the art; 
           [0033]      FIGS. 1G and 1H  schematically show a sectional side view and a cross-sectional view E-E of the profile and the structural insert of  FIGS. 1C and 1D , respectively, during a high pressure injection molding process, in accordance with an embodiment of the disclosure; 
           [0034]      FIGS. 2A and 2B  schematically show a top view and a side view, respectively, of an exemplary high pressure injection overmolding system, in accordance with another embodiment of the disclosure; 
           [0035]      FIG. 3  shows a flow diagram of a method of performing high pressure injection overmolding using the high pressure injection overmolding system of  FIG. 1A , in accordance with an embodiment of the disclosure; 
           [0036]      FIG. 4  schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system comprising a round profile and a non-solid insert, in accordance with another embodiment of the disclosure; 
           [0037]      FIG. 5  schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system comprising a quadrilateral profile and a solid insert, in accordance with another embodiment of the disclosure; 
           [0038]      FIG. 6  schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system comprising an octagonal profile and a solid insert, in accordance with another embodiment of the disclosure; and 
           [0039]      FIG. 7  schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system comprising a curved-edge quadrilateral profile and an irregular insert, in accordance with another embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    Reference is made to  FIGS. 1A and 1B  which schematically show a top view and a side view, respectively, of an exemplary high pressure injection overmolding system  100 , in accordance with an embodiment of the disclosure. Overmolding system  100  comprises a horizontal platform  110 , a mold  120 , profile supports  170 , a structural insert  140 , a first carrier  150 , and a second carrier  160 . The components comprised in overmolding system  100  are generally fabricated from a material adapted to resist the work environment encountered in a high pressure injection overmolding operation, for example, metals, metal alloys, ceramic materials, or others, or any combination thereof. 
         [0041]    In accordance with an embodiment of the disclosure, structural insert  140  is attached at a first end  145  to first carrier  150 , the first carrier adapted to slidingly push the structural insert into a profile  130 . First carrier  150  is further adapted to slidingly withdraw insert  140  from profile  130 . Following insertion of insert  140  through profile  130 , the insert is attached to second carrier  160  at an opposing second end  146  of insert  140 . Attachment of first end  145  and/or second end  146  to first carrier  150  and second carrier  160 , respectively, may be by the use of nuts and bolts, or by any other mechanical means, or combination of means, suitable for performing the attachment. In some embodiments of the disclosure, insert  140  may be adapted with threads at first end  145  and/or second end  146  for fitting the insert unto threaded holes (not shown) in first carrier  150  and/or second carrier  160 . Optionally, insert  140  may be integrally attached to first carrier  150  or second carrier  160  through welding. 
         [0042]    In some embodiments of the disclosure, insert  140  may be first attached at second end  146  to second carrier  160  and then attached at first end  145  to first carrier  150  following insertion through profile  140 . In some embodiments of the disclosure, insert  140  may be attached at only one end; either first end  145  or second end  146 , to only one of the carriers, either first carrier  150  or second carrier  160 , and the opposing end remains unattached to a carrier. 
         [0043]    Horizontal platform  110  is adapted to receive first and second carriers  150  and  160 , respectively, and insert  140 , such that the insert may be slidingly pushed into profile  130  by carrier  150 , or alternatively, by carrier  160 . Horizontal platform  110  is generally substantially parallel to a floor (not shown). In some embodiments of the disclosure, horizontal platform  110  may be vertically oriented, perpendicular to a floor, or optionally, at an angle with the floor. 
         [0044]    Arranged on horizontal platform  110  is mold  120 , which comprises profile supports  170 . Profile supports  170  are adapted to support profile  130  inside mold  120  during the overmolding process, a distance substantially equivalent to a thickness of a plastic coating on the profile. Profile supports  170  are adapted to be withdrawn from mold  120  when molten plastic injected into the mold is able to support a weight of profile  130 . Profile supports  170  may be manually and/or optionally, automatically withdrawn. Comprised in mold  120  are one or more injectors (not shown) through which the molten plastic is injected into the mold during the overmolding process. 
         [0045]    Reference is also made to  FIG. 1C  which schematically shows a cross-sectional view A-A of overmolding system  100 , in accordance with an embodiment of the disclosure. Reference is also made to  FIG. 1D  which schematically shows a cross-sectional view B-B (inner cross-section) of overmolding system  100 , in accordance with an embodiment of the disclosure. Profile  130  comprises a rigid, circular metal tube with a thin wall defined by an inner surface  136  and an outer wall  135 , extending along the length of the profile. In accordance with an embodiment of the disclosure, wall thickness between outer surface  135  and inner surface  136  may be equal to or greater than 0.1 mm. In some embodiments of the disclosure, profile  130 , which may hereinafter also be referred to as tube, may comprise a cross-section of substantially any geometrical shape, such as, for example, circular, elliptical, quadrilateral, pentagonal, hexagonal, heptagonal, octagonal, or other polygonal shape with more than eight sides, or any combination thereof. 
         [0046]    Structural insert  140  may be fabricated from any material adapted to resist temperatures of, for example 230-250 degrees Celsius, and up to approximately 300 degrees Celsius, typically associated with high pressure injection overmolding processes. Examples of such materials may be metals, metal alloys, ceramics, composites, and others. In some embodiments of the disclosure, insert  140  may be shaped such that only a portion of the insert comprises a cross-sectional shape corresponding to an inner cross-section of profile  130 , for example, a section the length of the profile that is placed inside the profile. The other sections may have a different cross-sectional shape and/or dimensions, and may be adapted for mating with corresponding mating sections in first carrier  150  and/or second carrier  160 . 
         [0047]    Profile  130  is shown inside mold  120  following the injection of molten plastic, as shown by plastic coating  105 , and following withdrawal of profile supports  170 . Structural insert  140  is shown inside of profile  130 , following being slidingly inserted through the profile by first carrier  150 , a relatively small clearance  137  existing between the insert and inside surface  136  to substantially prevent molten plastic from flowing into the clearance and possibly causing warps in the profile. Clearance  137  may be in the range between 0.05 mm and 1 mm, for example, 0.1 mm. 
         [0048]    In accordance with an embodiment of the disclosure, mold  120  is adapted to restrain profile  130  to allow insert  140  to be pulled out of the tube once the overmolding process is completed. Reference is also made to FIG.  1 D′ which schematically shows a cross-sectional view C-C of overmolding system  100 , in accordance with an embodiment of the disclosure. Mold  120  comprises a step  121  into which a section of a perimeter at each end of the profile  130  fits. A height of step  121  may be approximately equal to a thickness of plastic coating  105  and profile  130  wall thickness, or optionally less. Step  121  is adapted to acts as a barrier by pushing on the section of the perimeter at an end of tube  130  when insert  140  is to be pulled out of the tube, and is further adapted to not interfere with insert  140  removal. Optionally, mold  120  comprises a step  121  for a section of the perimeter at only one end of tube  130 . 
         [0049]    Reference is made to  FIGS. 1E and 1F , which schematically show a sectional side view and a cross-sectional view D-D of profile  130 , respectively, comprising insufficient interior reinforcement during a high pressure injection molding process; as known in the art. Molten plastic in streams at a relatively high pressure P 1 , shown by solid arrow  181 , is ejected from injectors  180  towards a section of outer wall  135  of profile  130 . The relative high pressure P 1  causes the wall of profile  130  on the side of injectors  180  to deform with maximum deformation in areas under the injectors, the amplitude of the deformation shown by dl. Furthermore, pressure P 1  pushes profile  130  toward supports  170 , the supports exerting a relative high pressure P 2 , shown by solid arrow  171 , against the wall of the profile on the side opposite P 1 . The relative high pressure P 2  causes the wall of the profile  130  on the side of supports  170  to deform, with maximum deformation in areas in the proximity of the supports. The deformation of the wall is shown by inner wall  136 A and outer wall  135 A, and extends along a whole length, or optionally a portion of the length, of profile  130 , the amplitude of the deformation shown by d 2 . 
         [0050]    Reference is made to  FIGS. 1G and 1H , which schematically show a sectional side view and a cross-sectional view E-E of profile  130  comprising structural insert  140 , respectively, during a high pressure injection molding process, in accordance with an embodiment of the disclosure. Molten plastic in streams at a relatively high pressure P 1 , shown by solid arrow  181 , is ejected from injectors  180  towards a section of outer wall  135  of profile  130 . Furthermore, pressure P 1  pushes profile  130  toward supports  170 , the supports exerting a relative high pressure P 2 , shown by solid arrow  171 , against the wall of the profile on the side opposite P 1 . 
         [0051]    In accordance with an embodiment of the disclosure, structural insert  140  is adapted to distribute pressures (forces) P 1  and P 2  over the whole of, or optionally a portion of, the insert, such that deformation of the walls of profile  130  is substantially prevented (the deformation amplitude is relatively small, less than 1 mm) The opposing distributed forces, P 3  and P 4 , shown by solid arrows  141  and  142 , respectively, are substantially equal, and opposite in direction to the forces P 1  and P 2 . 
         [0052]    In some embodiments of the disclosure, insert  140  may be fabricated from a material which comprises a coefficient of thermal expansion greater than that of profile  130 . The hot temperatures of the molten plastic causes insert  140  to expand more than profile  130 , closing clearance  137  between the insert and the profile. Following injection of the molten plastic, insert  140  and profile  130  are allowed to cool down, the insert contracting more than the profile to allow a relatively small clearance to develop. Insert  140  may then be withdrawn. Clearance  137  may be in the range from 0.05 mm-1 mm, for example 0.1 mm, depending on the material characteristics of insert  140  and profile  130 . Furthermore, structural insert  140  may be a circular, solid insert. Optionally, insert  140  may be a circular, non-solid insert. Optionally, structural insert  140  may be an irregular insert. 
         [0053]    Reference is made to  FIGS. 2A and 2B , which schematically show a top view and a side view, respectively, of an exemplary high pressure injection overmolding system  200 , in accordance with another embodiment of the disclosure. Overmolding system  200  comprises a horizontal platform  210 , a mold  220 , a step  221 , profile supports  270 , a structural insert  240 , a first carrier  250 , and a second carrier  260 . Horizontal platform  210 , mold  220 , step  221 , profile supports  270 , first carrier  250 , and second carrier  260  are the same or substantially similar to those shown in  FIGS. 1A and 1B  at  110 ,  120 ,  121 ,  170 ,  150 , and  160 . 
         [0054]    In accordance with some embodiments of the disclosure, structural inserts  240  and  241  are attached at a first end  245  and  246  to first carrier  250  and second carrier  260 , respectively. First carrier  250  and second carrier  260  are adapted to slidingly push structural inserts  240  and  241 , respectively, into profile  230 . Profile  230  may be the same or substantially similar to that shown in  FIGS. 1A and 1B  at  130 . Inserts  240  and  241  are inserted into profile  230  until second ends  247  and  248  on the inserts abut. Optionally, second ends  247  and  248  do not abut. First carrier  250  and second carrier  260  are further adapted to slidingly withdraw inserts  240  and  241 , respectively, from profile  230 . 
         [0055]    Attachment of first ends  245  and  246  to first carrier  250  and second carrier  260 , respectively, may be by the use of nuts and bolts, or by any other mechanical means, or combination of means, suitable for performing the attachment. In some embodiments of the disclosure, inserts  240  and/or  241  may be adapted with threads at first ends  245  and/or  246  for fitting the insert unto threaded holes (not shown) in first carrier  250  and/or second carrier  260 . Optionally, inserts  240  and/or  241  may be integrally attached to first carrier  260  or second carrier  260 , respectively, through welding. 
         [0056]    Reference is made to  FIG. 3 , which shows a flow diagram of a method of performing high pressure injection overmolding using high pressure injection overmolding system  100  shown in  FIGS. 1A and 1B , in accordance with an embodiment of the disclosure. Optionally, the method may be performed with high pressure injection overmolding system  200  shown in  FIGS. 2A and 2B . It may be appreciated by a person skilled in the art that the method described herein may be applied in other sequences for the described embodiments, and may be applied in the same sequence described, or in other sequences, to other embodiments of the disclosure.
   [STEP  301 ] Mold  120  is opened and profile  130  is placed on profile supports  170  inside the mold. A height of profile supports  170  is adjusted according to the thickness of plastic coating  105 , and a number of profile supports is used, according to a weight of the profile and/or injection pressure.   [STEP  302 ] Profile  130  is secured inside mold  120     [STEP  303 ] Insert  140  is pushed through profile  130 .   [STEP  304 ] Mold  120  is closed.   [STEP  305 ] Molten plastic is injected into mold  120 . Profile supports  170  are removed when plastic coating  105  is capable of supporting the weight of profile  130 .   [STEP  306 ] Following application of plastic coating  105  along an entire length of profile  130 , injection of molten plastic is stopped and mold  120  is allowed to cool down for a period of time (cooling down period) ranging from 1 to 40 seconds, for example 5 to 20 seconds, 10 to 30 seconds, 20-40 seconds.   [STEP  307 ] Open mold  120 .   [STEP  308 ] Slidingly withdraw insert  140  from profile  130 .   [STEP  309 ] Remove profile  130  comprising plastic coating  105 .   
 
         [0066]    Reference is made to  FIG. 4 , which schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system  400  comprising a round profile  430  and a non-solid insert  440 , in accordance with another embodiment of the disclosure. Profile  430  is shown inside mold  420  following injection of molten plastic, as shown by plastic coating  405 . Structural insert  440  is shown inside profile  430 , a relatively small clearance  437  separating between the profile and the insert. High pressure injection overmolding system  400 , including profile  430 , mold  420 , insert  440 , plastic coating  405 , and clearance  437 , may be the same or substantially similar to that shown in  FIGS. 1A and 1B  at  100 , including  130 ,  120 ,  140 ,  105 , and  137 . Optionally, high pressure injection overmolding system  400 , including profile  430 , mold  420 , insert  440 , plastic coating  405 , and clearance  437 , may be the same or substantially similar to that shown in  FIGS. 2A and 2B  at  200 , including  230 ,  220 ,  240 ,  205 , and  237 . 
         [0067]    Reference is made to  FIG. 5 , which schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system  500 , comprising a quadrilateral profile  530  and a solid insert  540 , in accordance with another embodiment of the disclosure. Profile  530  is shown inside mold  520  following injection of molten plastic, as shown by plastic coating  505 . Structural insert  540  is shown inside profile  530 , a relatively small clearance  537  separating between the profile and the insert. High pressure injection overmolding system  500 , including profile  530 , mold  520 , insert  540 , plastic coating  505 , and clearance  537 , may be the same or substantially similar to that shown in  FIGS. 1A and 1B  at  100 , including  130 ,  120 ,  140 ,  105 , and  137 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. Optionally, high pressure injection overmolding system  500 , including profile  530 , mold  520 , insert  540 , plastic coating  505 , and clearance  537 , may be the same or substantially similar to that shown in  FIGS. 2A and 2B  at  200 , including  230 ,  220 ,  240 ,  205 , and  237 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. 
         [0068]    Reference is made to  FIG. 6 , which schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system  600  comprising an octagonal profile  630  and a solid insert  640 , in accordance with another embodiment of the disclosure. 
         [0069]    Profile  630  is shown inside mold  620  following injection of molten plastic, as shown by plastic coating  605 . Structural insert  640  is shown inside profile  630 , a relatively small clearance  637  separating between the profile and the insert. High pressure injection overmolding system  600 , including profile  630 , mold  620 , insert  640 , plastic coating  605 , and clearance  637 , may be the same or substantially similar to that shown in  FIGS. 1A and 1B  at  100 , including  130 ,  120 ,  140 ,  105 , and  137 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. Optionally, high pressure injection overmolding system  600 , including profile  630 , mold  620 , insert  640 , plastic coating  605 , and clearance  637 , may be the same or substantially similar to that shown in  FIGS. 2A and 2B  at  200 , including  230 ,  220 ,  240 ,  205 , and  237 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. 
         [0070]    Reference is made to  FIG. 7 , which schematically shows a cross-sectional view of a portion of a high pressure injection overmolding system  700  comprising a curved-edge quadrilateral profile  730  and an irregular insert  740 , in accordance with another embodiment of the disclosure. Profile  730  is shown inside mold  720  following injection of molten plastic, as shown by plastic coating  705 . Structural insert  740  is shown inside profile  730 , a relatively small clearance  737  separating between the profile and the insert. High pressure injection overmolding system  700 , including profile  730 , mold  720 , insert  740 , plastic coating  705 , and clearance  737 , may be the same or substantially similar to that shown in  FIGS. 1A and 1B  at  100 , including  130 ,  120 ,  140 ,  105 , and  137 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. Optionally, high pressure injection overmolding system  700 , including profile  730 , mold  720 , insert  740 , plastic coating  705 , and clearance  737 , may be the same or substantially similar to that shown in  FIGS. 2A and 2B  at  200 , including  230 ,  220 ,  240 ,  205 , and  237 , except for variations pertaining to a shape of the profile and/or insert as shown in the figure. 
         [0071]    It may be appreciated by a person skilled in the art that the shapes of the profiles and inserts shown in the different embodiments are for illustrative purposes only, and are not intended to be limiting in any way. Numerous shapes of profiles and inserts may be used, an exemplary few shown herein. 
         [0072]    In the description and claims of embodiments of the present disclosure, each of the words, “comprise” “include” and “have”, and forms thereof, are not necessarily limited to members in a list with which the words may be associated. 
         [0073]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced be interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.