Abstract:
The present invention provides a lighting system for use within a display sign, wherein the lighting system comprises a first module having a multi-layer circuit board and an arrangement of components electrically connected to the circuit board. The component arrangement includes a driver control chip that provides regulated voltage to the light emitting diodes, at least one surface mounted resistor, and a pair of light emitting diodes wherein each diode is mounted to a longitudinal end portion of the circuit board. Thus, the driver control chip is positioned between the light emitting diodes. The component arrangement further includes a high-frequency capacitor that filters undesired electrical noise and a rectifying diode that converts electrical potential from alternating current to direct current. A second module is electrically connected to the first module by a pair of flexible conductor wires. The second module includes a multi-layer circuit board and an arrangement of components electrically connected to the circuit board. The component arrangement of the second module is similar to that of the first module, wherein a light emitting diode is mounted to each longitudinal end portion of the circuit board.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   Pursuant to 35 U.S.C. §120, this Application is a continuation application of Ser. No. 10/948,824, now U.S. Pat. No. 7,165,863, filed on Sep. 23, 2004, issued on Jan. 23, 2007, and thereby claims the benefit of that Application. 

   TECHNICAL FIELD 
   The present invention relates to an illumination system and more particularly to providing high-power, high-intensity light emitting diode modules that are economic to produce and operate. 
   BACKGROUND OF THE INVENTION 
   Recent improvements in the growth and manufacture of the crystals utilized in the production of the light emitting diodes has permitted greater utility and flexibility for its use as an alternative to standard sign industry lighting sources such as neon, fluorescent, cold cathode, metal halide, incandescent and high pressure sodium light sources. Light emitting diodes offer a low voltage alternative to the standard or high voltage lighting sources mentioned. Further developments in light emitting diodes technology have permitted a greater ability to modulate the intensity and light output expanding the potential applications for light emitting diodes lighting technology. Various industries, including the sign industry, have maximized this benefit to produce new and useful and unobvious illumination patterns and techniques. 
   Various corporations have introduced the improved light emitting diodes utilizing different and varying approaches to achieving similar lighting applications in the signage industry. Light emitting diode lighting systems are strung together in different and varying configurations. Further advancements have been made and light emitting diodes technology has been accepted in mainstream use as a superior lighting alternative as evidenced by street signal lighting and changing traffic signals beginning to convert to arrayed light emitting diodes as the preferred lighting for its intensity, visibility and clarity. 
   The use of illumination systems of known designs and configurations is known in the prior art. More specifically, illumination systems of known designs and configurations previously devised and utilized for the purpose of illumination with light emitting diodes are known to consist basically of familiar, expected, and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which has been developed for the fulfillment of countless objectives and requirements. 
   By way of example, U.S. Pat. No. 6,394,626 to McColloch discloses a flexible light track for signage. U.S. Pat. No. 6,371,637 to Atchinson et al. discloses a compact, flexible LED array. U.S. Pat. No. 6,283,612 to Hunter discloses a light emitting diode light strip. U.S. Pat. No. 6,167,648 to Dimmick discloses an illuminated modular sign having adjustable quick release modules. U.S. Pat. No. 5,931,577 to Ishibashi discloses a display device and method for making the same. U.S. Pat. No. 5,924,785 to Zhang et al. discloses a light source arrangement. U.S. Pat. No. 6,346,777 to Kim discloses an LED lamp apparatus. Lastly, U.S. Pat. No. 6,072,280 to Allen discloses an LED light string employing series-parallel block coupling. 
   While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe an illumination system that allows providing high-power, high-intensity light emitting diode modules that are economic to produce and operate. 
   In this respect, the illumination system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of providing high-power, high-intensity light emitting diode modules that are economic to produce and operate. 
   The present invention relates to a linear, linked and stranded high-power, high-intensity light emitting diode illumination system utilizing modules with a metal-core, ceramic coated printed circuit board with surface mounted electrical components required to produce light through the plurality of light emitting diodes. The present invention also relates to improvements in light emitting diodes and advancements in design specification, printed circuit board layouts and electrical component configurations. The present invention, through its specific design, most efficiently utilizes the minimum amount of low voltage electricity to maximize lighting intensity across the standard lighting spectrum, i.e., red range, amber, orange, blue, white, and green. The present invention, referencing specific electrical component configurations and anticipated flow of electrical current, when segmented units are utilized singularly or in plurality, minimizes “voltage resistance drop” across a segmented unit or a group in parallel, calculated in Ohms. 
   Therefore, it can be appreciated that there exists a continuing need for a new and improved illumination system which can be used for providing high-power, high-intensity light emitting diodes that are economic to produce and operate. In this regard, the present invention substantially fulfills this need. 
   SUMMARY OF THE INVENTION 
   In view of the inherent limitations regarding conventional lighting systems as well as solid state lighting systems, the present invention moves the development of high-power, high intensity light emitting diodes into a system that is both economic to produce as well as economic to operate. 
   In view of the foregoing disadvantages inherent in the known types of illumination systems of known designs and configurations now present in the prior art, the present invention provides an improved light emitting diode illumination system. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved light emitting diode illumination system and method which has all the advantages of the prior art and none of the disadvantages. 
   To attain this, the present invention essentially comprises at least one module with a metal-core, ceramic coated printed circuit board assembly, and a specifically designed heat-sink. The metal-core, ceramic coated printed circuit board is rectangular in configuration. The metal-core, ceramic coated printed circuit board has front and back faces. The metal-core, ceramic coated printed circuit board segments have electrical elements coupled to the front face. The electrical elements include two or more light emitting diodes, and a plurality of resistors. The metal-core, ceramic coated printed circuit board has a single associated high-frequency “noise” filtering capacitor and a plurality of associated rectifying diodes. The rectifying diodes convert AC to DC. One pair of inverted electrical insulation displacement connectors are affixed for the first time on the back side of the metal-core, ceramic coated printed circuit board with through-hole technology, that couple the light emitting diode module to a pair of continuous individual stranded and insulated copper core conductor wires. These connectors are capable of coupling the electrical elements to a source of electrical potential. In this manner the light emitting diodes are illuminated with minimum current while generating minimum heat. 
   More particularly, the present invention essentially comprises a plurality of similarly configured modules. Each module has a metallic mass with an elongated upper component and an elongated lower component. Each upper component includes a generally flat lower surface and upper surface with laterally spaced wiring channels and a central longitudinal void there between. Each upper component also includes curved sides with outwardly extending fins for heat sink purposes. Each lower component has a lower surface with a longitudinal depressed area with a foam tape there within and an upper surface coupled to the lower surface of the upper component. Each lower component has a length greater than the length of its associated upper component to form a mounting tab with a mounting aperture there through. 
   Each module also has a circuit board with a front face and a back face mounted on the upper surface of the upper component. Each circuit board is fabricated of an insulating bottom layer with trace patterns thereon and forming the back face. The bottom layer is fabricated of multi-layers of dissimilar material construction with a bottom layer consisting of high grade steel, a second layer consisting of a dielectric coating, a third layer consisting of the copper trace layer, a fourth layer consisting of an additional sandwiching dielectric layer, and a final ceramic coated top layer. 
   Next provided is a plurality of electrical components coupled to the trace patterns of each circuit board. Such electrical components include two high-power high-intensity light emitting diodes, a light emitting diode driver control chip, a single high-frequency cap filter to abate “noise”, rectifying diodes that convert electrical potential from AC to DC, surface mounted resistors of specific values to regulate the electrical potential and illuminate the light emitting diodes. Each circuit board has two pairs of small holes for the passage of the insulation displacement connectors and one pair of large holes for machine screws to couple the circuit boards to the metallic mass extending there through. 
   Each module also has a translucent cap cover positionable over the central extent of an associated circuit board with a generally semi-cylindrical upper surface and lateral snap tabs adapted to couple with its associated circuit board. 
   Next provided is a pair of alternating current carrying continuous insulated stranded copper core conductor wires coupling the plurality of modules in parallel. Each wire extends through aligned wiring channels of the upper components of the modules. These wires are continuous and unsegmented. A cross cut channel is formed in the upper component of the mass for allowing the electrical components to couple with the wires. 
   Lastly, pairs of electrically conductive insulation displacement connectors extend through each of the circuit boards in proximity to their ends with upper ends coupled with the trace patterns and lower ends extending into the cross-cut channels to frictionally affix, and electrically couple, the connectors and the wires. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached. 
   In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
   As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
   According to one aspect of the invention, the illumination system provides a new and improved linear, stranded and linked high-power, high-intensity light emitting diode illumination system comprising a metal-core, ceramic coated printed circuit board, and a specifically designed heat-sink. The metal-core, ceramic coated printed circuit board is in a rectangular configuration. The metal-core, ceramic coated printed circuit board has front and back faces. The metal-core, ceramic coated printed circuit board has electrical elements coupled to the front face. The electrical elements include two or more light emitting diodes, and a plurality of resistors. The metal-core, ceramic coated printed circuit board has a single associated high-frequency “noise” filtering capacitor and a plurality of associated rectifying diodes. The rectifying diodes convert AC to DC. One pair of inverted electrical insulation displacement connectors are affixed for the first time on the back side of the metal-clad printed circuit board with through-hole technology, that couple the light, emitting diode module to a pair of continuous individual stranded and insulated copper core conductor wires. These connectors are capable of coupling the electrical elements to a source of electrical potential. In this manner the light emitting diodes are illuminated with minimum current while generating minimum heat. 
   According to another aspect of the invention, illumination system includes a module with a metallic mass with an upper surface having laterally spaced wiring channels and outwardly extending fins, a circuit board mounted on the module and fabricated of an insulating bottom layer with trace patterns thereon, a plurality of electrical components, including at least one light emitting diode, coupled to the trace patterns of the circuit board, a pair of conductor wires coupling the electrical components with each wire and extending through the wiring channels of the module, and at least one pair of connectors extending through the circuit board with upper ends coupled with the trace patterns and lower ends extending downwardly to electrically couple with the continuous wires. 
   For a better understanding of the present invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings as well as the descriptive matter in which there is illustrated and described the preferred embodiment of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
       FIG. 1  is a perspective illustration of the illumination system, including coupling between system modules constructed in accordance with the principles of the present invention. 
       FIG. 2A  is an enlarged perspective illustration of a module as depicted in  FIG. 1 . 
       FIG. 2B  is an enlarged perspective illustration of a printed circuit board of the module, without the presence of a protective plastic cover for illustrative purposes. 
       FIG. 3A  is a top plan view of the printed circuit board showing a copper trace pattern. 
       FIG. 3B  is a bottom plan view of the printed circuit board. 
       FIG. 3C  is an elevation side view of the horizontal plane of the printed circuit board showing the various layers of the board. 
       FIG. 3D  is an elevation end view of the printed circuit depicting the layers of the board. 
       FIG. 4A  is a sectional view of a heat sink mass of the module. 
       FIG. 4B  is an elevation side view of the heat sink mass. 
       FIG. 4C  is a top plan view of the heat sink mass. 
       FIG. 5  is a sectional view of the module, including the cover, constructed in accordance with the principles of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With reference now to the drawings, and in particular to  FIG. 1  thereof, the preferred embodiment of the new and improved illumination system embodying the principles and concepts of the present invention and generally designated by the reference numeral  10  will be described. 
   The present invention, the illumination system  10  is comprised of a plurality of components. Such components in their broadest context include a module  12  having a printed circuit board assembly  32 , a plurality of electrical components  37 , a pair of conductor wires  56  and at least one pair of connectors  60 . Such components are individually configured and correlated with respect to each other so as to attain the desired objective. 
   A plurality of similarly configured modules  12  is first provided. Each module  12  has a metallic heat sink mass  14  with an elongated upper component  16  and an elongated lower component  18 . Each upper component  16  includes a generally flat lower surface  16   a  and upper surface  16   b  with laterally spaced wiring channels  20  and a central longitudinal void  21  there between. Each upper component  16  also includes curved sides  16   c  with outwardly extending fins  22  for heat sink purposes. Each lower component  18  has a lower surface  18   a  with a longitudinal depressed area  24  with a foam tape  26  there within, and an upper surface  18   b  coupled to the lower surface  16   a  of the upper component  16 . Each lower component  18  has a length greater than the length of its associated upper component to form a mounting tab  28  with a mounting aperture  30  there through. 
   Each module  12  also has a circuit board assembly  32  with a front face  34  and a back face  36  mounted on the upper surface  16   b  of the upper component  16 . Each circuit board assembly  32  comprises a bottom layer  38   a  fabricated from multi-layers of dissimilar material construction such as high grade steel, a second layer  38   b  consisting of a dielectric coating, a third layer  38   c  having a copper trace pattern  39 , a fourth layer  38   d  consisting of an additional sandwiching dielectric coating, and a top or fifth layer  38   e  of ceramic coating. 
   Next provided is a plurality of electrical components  37  coupled to the trace patterns  39  of each circuit board  32 . Such electrical components  37  include two high-power, high-intensity light emitting diodes  40 , a light emitting diode driver control chip  41 , a single high-frequency cap filter  42  to abate “noise”, rectifying diodes  44  that convert electrical potential from AC to DC, surface mounted resistors  46  of specific values to regulate the electrical potential and illuminate the light emitting diodes  40 . Each circuit board  32  has two pairs of small holes  48  for the passage of insulation displacement connectors  60  and one pair of large holes  50  for machine screws to couple the circuit boards to the metallic mass. 
   Each module  12  also has a translucent cap cover  52  positionable over the central extent  32   a  of an associated circuit board  32  with a generally semi-cylindrical upper surface  52   a  and lateral snap tabs  54  adapted to couple with its associated circuit board. 
   Next provided is a pair of alternating current carrying continuous insulated stranded copper core conductor wires  56  coupling the plurality of modules  12  in parallel. Each wire  56  is coupled during operation to a potential source of alternating current and extends through aligned wiring channels  20  of the upper component  16  of the modules  12 . A cross cut channel  58  is formed in the upper component  16  for allowing the electrical components to couple with the wires  56 . 
   Lastly, pairs of electrically conductive insulation displacement connectors  60  extend through each of the circuit boards  32  in proximity to their ends with upper ends  62  coupled with the trace patterns and lower ends  64  extending into the cross cut channel  58  to frictionally affix, and electrically couple, the connectors  60  and the wires  56 . 
   With greater specificity and as shown in the illustrations,  FIG. 1  is a perspective illustration of the coupling between system segments or modules  12  depicting a sectional view of a continuous, light emitting diode illumination system  10  constructed in accordance with the principles of the present invention. In this preferred embodiment of the lighting system  10 , the individual lighting modules  12  are linked together in a linear fashion in parallel, by and affixed to, a pair of continuous insulated and stranded copper core conductor wires  56 . These modules  12 , when coupled to a power supply (not shown), can operate and function as a lighting unit singularly or in plurality, only limited by the amount of electrical potential available from the power supply and the laws of physics pertaining to electricity. 
     FIG. 2A  is an enlarged perspective illustration of a segment  12  with the protective plastic cover  52  in place over the exposed electrical components  37  of the lighting device module  12 , otherwise referred to as a pod, which individually or in plurality, as depicted in  FIG. 1 , constitutes a light source.  FIG. 2B  is and enlarged perspective illustration of the metal-core, ceramic coated printed circuit board  32  with all of the surface mounted electrical components  37  and light emitting diodes  40  affixed in the proper operational positions without the presence of the protective plastic cover  52  for illustrative purposes. 
   In these Figures, the printed circuit board  32  has a rectangular configuration. The printed circuit board  32  has front  34  and back  36  faces. The metal-core, ceramic coated printed circuit board  32  has electrical elements  37  coupled to the front face  34 . The material for the bottom or metal-core layer  38   a  is preferably a heat conductive metal selected from the class of conductive metals including steel, stainless steel, aluminum and the like. The electrical elements  37  further include two light emitting diodes  40 , a plurality of resistors  46  and a high-frequency “noise” filtering capacitor  42 . There is a plurality of associated rectifying diodes  44 . The rectifying diodes  44  convert alternating current (AC) to direct current (DC). One pair of inverted electrical insulation displacement connectors is provided. There is a light emitting diode control driver chip  41  which functionally provides clean and regulated electrical potential to energize and illuminate the light emitting diodes  40 . An injection molded plastic cap/cover  52  is provided to cover the electrical elements from environmental detriments and intrusions. Quick-snap tabs  54  are molded into the cap  52  to frictionally attach the plastic cap/cover over the metal-core, ceramic coated printed circuit board  32  and onto the heat sink fins  22 . 
     FIG. 3A  is a top plan view of the metal-core, ceramic coated printed circuit board  32  showing the copper trace pattern  39  and the top view of the through-hole  50  positions for the machine screw to mechanically fasten the metal-core, ceramic coated printed circuit board  32  to the metal heat sink mass  14  shown in  FIG. 4 . Additionally,  FIG. 3A  shows the positions of the through-hole  48  positions for the insertion of the insulation displacement connectors  60  so they may be affixed untraditionally and uniquely to the bottom layer  38   a  of a single-sided metal-clad printed board  32 .  FIG. 3B  is a bottom plan view of the metal-core, ceramic coated printed circuit board  32 . The through-hole  50  positions for the machine screw to mechanically fasten the metal-core, ceramic coated printed circuit board  32  to the metal heat sink mass  14  and the through-hole  48  positions for the insulation displacement connectors  60 .  FIG. 3C  is a elevation side view of the horizontal plane of the metal-core, ceramic coated printed circuit board  32  depicting the layers  38   a - e  incorporated in the manufacture of the metal-core, ceramic coated printed circuit board  32  which, as explained above, is comprised of a steel base substrate bottom layer  38   a,  a dielectric coating second layer  38   b,  a copper trace third layer  38   c,  a dielectric coating layer  38   d,  and a top dielectric ceramic coating or finishing layer  38   e.    FIG. 3D  is an elevation or sectional end view of the horizontal plane of the printed circuit board  32  depicting the five layers  38   a - e.    
     FIG. 3A  illustrates the front face  34  of the printed circuit board  32  showing the copper trace pattern  39  necessary for the electrical elements  37 , once attached, to function in the intended manner, while  FIG. 3B  shows the back face  36  of the metal-core, ceramic coated printed circuit board  32 . Illustrated are the pre-stamped holes  50  for attachment of the machine screws, and the inverted insulation displacement connector holes  48 . Shown in  FIG. 3C  is a profile view of the metal-core, ceramic coated printed circuit board  32  which shows the layers  38   a - e  that make up the substrate, that includes two dielectric coating layers  38   d, b  that sandwich a copper trace layer  38   c.  The bottom layer  38   a  consists of a high-grade steel for rigidity, even thermal distribution and transfer. Additionally,  FIG. 3D  is a sectional view with the same material and component description as  FIG. 3C . 
     FIG. 4A  is a sectional view of the typical cross-section of the metal heat sink mass  14  specifically designed to dissipate heat, mechanically fasten to the metal-core, ceramic coated printed circuit board  32 , and allow for the positioning of the continuous insulated and stranded copper core conductor wires  56  in the appropriate wire channels  20 , including the fins  22  for heat dissipation, a cut out depression  24  in the base  18  of the device  14  for double-sided tape  26  for fastening, as well as a tabbed extension  28  with a pre-drilled hole  30  for optional mechanical fastening to a substrate. 
     FIG. 4B  is an elevation side view of the metal heat sink mass  14  specifically designed to dissipate heat, mechanically fasten to the metal-core, ceramic coated printed circuit board  32 , and allow for the positioning of the continuous insulated and stranded copper core conductor wires  56  in the appropriate wire channels  20 , including the fins  22  for heat dissipation, a cut out depression  24  in the base  18  of the device  14  for double-sided tape  26  for fastening as well as a tabbed extension  28  with a pre-drilled hole  30  for optional mechanical fastening to a substrate. There is depicted a cross cut  58  to allow for a void area  58   a  in order for the inverted insulation displacement connectors  60  to be placed on the bottom side or face  36  of the metal-core, ceramic coated printed circuit board  32  after it is mechanically fastened to the heat sink mass  14 . 
     FIG. 4C  is a top plan view of the metal heat sink mass  14  specifically designed to dissipate heat, mechanically fasten to the metal-core, ceramic coated printed circuit board  32 , and allow for the positioning of the insulated and stranded copper core conductor wires  56  in the appropriate wire channels  20 , including the fins  22  for heat dissipation, a cut out depression  24  in the base  18  of the device  14  for double-sided tape  26  for fastening as well as a tabbed extension  28  with a pre-drilled hole  30  for optional mechanical fastening to a substrate. There is a depicted cross cut  58  to allow for a void area  58   a  in order for the inverted insulation displacement connectors  60  to be placed on the bottom side or face  36  of the metal-core, ceramic coated printed circuit board  32  after it is mechanically fastened to the heat sink mass  14 . 
   A profile view of the specially designed metallic mass  14  is shown in  FIG. 4A . It is used as a heat sink to dissipate heat energy created from the operation of a module  12  of the illumination system  10  into an attached substrate or ambient air by way of the air cooled fin  22  design present on both sides of the length of the heat sink mass  14 . Specific architecture is employed in the design of this device. There is a depressed area  24  designed to accept a length of double-sided adhesive foam tape  26  in order to act as an alternative method of attachment singularly or in conjunction with the metal mounting tab  28 . Wiring channels  20  are provided to allow the continuous insulated conductor wires  56  to pass through the upper body component  16  of the heat sink mass  14  and fasten to the insulation displacement connectors  60  in a cross cut channel  58  in  FIG. 4B  and  FIG. 4C . Mechanical fastening of the machine screw (not shown) through the hole  50  on the metal-core, ceramic coated printed circuit board  32  and into the specific void in the heat sink mass  14  allow for this during assembly. 
     FIGS. 4B and 4C  show a cross-cut tab where the extruded body of the heat sink mass  14  has specifically been removed to create a mounting tab  28 , which has a pre-drilled hole  30  intended for mechanical fastening to a substrate or object by way a standard sized bolts and nuts, rivets, or screws. 
     FIG. 5  is the end or sectional view the entire light emitting diode illumination module, pod, or unit  12 , constructed in accordance with the principles of the present invention and illustrating the primary embodiment of the invention. Additionally the double-sided adhesive foam tape  26  is depicted by a dashed rectangle in the depression area  24  of the heat sink mass  14 . 
   The present invention allows significantly increased tolerances for electrical component configuration. The present invention has been configured to reduce operating temperature of the light emitting diodes  40  while maximizing the dissipation of ambient heat of the printed circuit board  32  created during its operation. This consideration further expands the range of applications this invention can be utilized in such as refrigeration environments where earlier forms of light emitting diode lighting systems maximized heat output, without consideration, to the detriment of the system component and/or the environment in which it is utilized. 
   As to the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided. 
   With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
   Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.