Patent Application
20090200777
This present invention relates generally to airbags or inflatable cushions for vehicles. More specifically, the present invention relates to systems and methods for controlling the deployment of an inflatable cushion of an airbag module.
Airbag modules have become common in modern automobiles. An airbag module typically comprises an inflatable cushion and an inflator within a housing. The module is installed in a desired position within the vehicle, such as the steering wheel, the dashboard, the seat, vehicle doors; the A-pillar, and other locations. The inflatable cushion is stored in a folded position within the housing in fluid communication with the inflator. In response to an activation event or occurrence, a sensor provides a signal for activating the inflator. The inflator provides a supply of inflating gas to the cushion to inflate the cushion, deploying it from the housing into the vehicle.
Various methods have been employed to tie the inflation level of the inflatable cushion to specific conditions.
Accordingly, it is desirable to provide an airbag module with an apparatus or system that can provide a signal to vary the inflation rate or venting rate of the airbag module.
Disclosed herein is a device and method for manipulating the deployment characteristics of an inflatable cushion of an airbag module. Exemplary embodiments of the present invention are directed to a method and apparatus to change the level of inflation of a passenger side airbag based on an occupant's or other object's proximity to the deploying airbag. In one exemplary embodiment a small foam plug or deployable member is propelled through the folded cushion toward an area proximate to the airbag module wherein the deployable member is propelled using the inflation forces of the first stage of the inflator. In this embodiment, a thread attached to the plug pulls a switch to signal the sensing and diagnostic module that the deployable member has not encountered an obstruction and the signal is used to enable the second inflator stage. In another exemplary embodiment, a contact-type electro-mechanical sensor will determine if an occupant or other object is close to the deploying inflatable cushion in this embodiment if the occupant is in close proximity the deployment is suppressed alternatively, the cushion will fill with the needed energy to fully inflate the cushion. In this embodiment either a separate squib or the inflator energy is used to deploy the contact sensor.
In accordance with an exemplary embodiment, an air bag module for use in a vehicle is provided. The air bag module, comprising: an inflatable cushion being configured for deployment from the air bag module; an inflator for inflating the inflatable cushion, the inflator being in fluid communication with the inflatable cushion, the inflator comprising a first initiator for initiating a first stage of inflation and a second initiator for use with the first initiator for initiating a second stage of inflation, the first stage of inflation providing a first inflation output to the inflatable cushion and the second stage producing a second inflation output to the inflatable cushion, the second inflation output being greater than the first inflation output; a deployable member, the deployable member being deployed in a first direction either before or during the first stage of inflation; and wherein unobstructed deployment of the deployable member in the first direction will cause an activation signal to be sent to the second initiator to initiate the second stage of inflation.
In accordance with another exemplary embodiment, an air bag module for use in a vehicle is provided. The air bag module, comprising: an inflatable cushion being configured for deployment from the air bag module; an inflator for inflating the inflatable cushion, the inflator being disposed within a plenum, the plenum comprising a first plurality of openings in fluid communication with the inflatable cushion, a second plurality of openings in fluid communication with an exterior of the airbag module; and a conduit in fluid communication with a plate housing; a deployable member slidably received within the plate housing, the deployable member being deployed in a first direction during activation of the inflator; a rotary valve rotatably disposed within the plenum the rotary valve being configured to transition from a first position to a second position, wherein the first plurality of openings are blocked by the rotary valve in the first position and second plurality of openings are unblocked by the rotary valve in the first position; and wherein unobstructed deployment of the deployable member in the first direction will cause the rotary valve to transition from the first position to the second position, wherein the first plurality of openings are unblocked by the rotary valve in the second position and the first plurality of openings are blocked by the rotary valve in the second position.
In accordance with another exemplary embodiment, a proximity detection device for use in a vehicle is provided. The proximity detection device, comprising: a deployable member, the deployable member being deployed in a first direction either before or during inflation of the inflatable cushion; and wherein unobstructed deployment of the deployable member in the first direction will cause an inflation output to the inflatable cushion to be increased.
In accordance with another exemplary embodiment, a method for determining whether a portion of an inflatable cushion of an airbag module is obstructed is provided. The method comprising: deploying a deployable member in a first direction; increasing an inflator output to the inflatable cushion if the deployable member reaches a predetermined distance, wherein the deployable member is not an inflatable item.
The above-described and other features of the present application will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
Disclosed herein is a method and apparatus for selectively controlling the deployment or inflation of an inflatable cushion of an airbag module through the use of a deployable member disposed within and/or proximate to the inflatable cushion. In accordance with an exemplary embodiment, a force sufficient for deployment of the deployable member is provided. In addition, an inflation force is also provided by an inflator to inflate the inflatable cushion, in one embodiment the inflator comprises a first initiator for initiating a first stage of inflation and a second initiator for use with the first initiator for initiating a second stage of inflation, the first stage of inflation providing a first inflator output to the inflatable cushion. During the first stage of inflation the deployable member is deployed in a first direction, wherein unobstructed deployment of the deployable member in the first direction will cause a signal to be ultimately sent to the second initiator to initiate the second stage of inflation. If, however, the deployable member does not deploy in an un-obstructed manner no activation signal will be sent to the second initiator and only the first initiator will be fired.
In accordance with one exemplary embodiment the inflator is a dual stage inflator capable of providing two inflation outputs at selected times. Of course, other types of inflators maybe used in accordance with exemplary embodiments of the present invention. Non-limiting examples of exemplary inflators include but are not limited to pure gas inflators, hybrid inflators, pyrotechnic inflators, and equivalents thereof.
Referring now to the Figures, and in particular to
A sensor or sensing-and-diagnostic module 22 is adapted to detect an activation event wherein the occurrence of a threshold event will cause an activation signal 24 to be generated and received by the inflator 18, thereby causing the inflator to inflate the inflatable cushion. The detection of the threshold event is determined by one or more sensors, which are disposed about the vehicle in accordance with known technologies. Thus, the activation signal 24 controls the activation of the airbag module 14. In an exemplary embodiment sensing-and-diagnostic module 22 comprises a microprocessor, microcontroller or other equivalent processing device capable of executing commands of computer readable data or program for executing a control algorithm that controls the operation of the airbag module. In order to perform the prescribed functions and desired processing, as well as the computations therefore (e.g., the execution of fourier analysis algorithm(s), the control processes prescribed herein, and the like), the controller may include, but not be limited to, a processor(s), computer(s), memory, storage, register(s), timing, interrupt(s), communication interfaces, and input/output signal interfaces, as well as combinations comprising at least one of the foregoing. For example, the controller may include input signal filtering to enable accurate sampling and conversion or acquisitions of such signals from communications interfaces. As described above, exemplary embodiments of the present invention can be implemented through computer-implemented processes and apparatuses for practicing those processes.
The inflatable cushion is stored in a folded or un-deployed position in housing 16. The cushion is positioned to be in fluid communication with the inflator 18 wherein generation of the inflating gas will cause the cushion to inflate. Upon detection of an activation event by the sensing-and-diagnostic module 22, the inflator 18 is activated via signal 24 to generate the inflation gas. The inflation gas causes the cushion 20 to inflate and expand from housing 16 into the interior of the vehicle. It should be recognized that module 14 is illustrated by way of example only as being included in the dashboard of the vehicle. Of course, it is contemplated that module 14 can be installed for deployment in other regions of the vehicle, such as, but not limited to a forward facing position, a mid-mount location, the steering wheel, the seat, the A-pillar, the roof, and other locations as well as other angular or positional relationships illustrated in
Additionally, the present disclosure is also contemplated for use with various types of inflatable cushions and inflators. For example, cushions which are folded in a particular manner to achieve various deployment configurations and various types of inflators (e.g., dual stage inflators).
In addition, and in accordance with the alternative exemplary embodiments of the present invention, the sensing-and-diagnostic module can also be adapted to detect one or more conditions of the seating structure. For example, sensing-and-diagnostic module 22 can be adapted to detect one or more of the following: a load or amount of load (e.g., occupant weight) on the seating structure 12, a position of the seating structure, an angle of a portion of the seating structure with respect to another portion, the distance the seating structure is from the air bag module 14, and other data that is relevant to the deployment of the airbag by receiving input from a plurality of sensors disposed about the vehicle.
For example, the sensing-and-diagnostic module can receive inputs from one or more sensors such as, but not limited to, a seat position sensor 26, an optical scanner 28, a load sensor 30, a seat recline sensor 32, a seat belt use detection sensor 34, and a belt tensioning sensor (not shown). The sensors are positioned to provide input signals to module 22 indicative of one or more seat conditions. The one or more seat conditions combined with an occupant's size (e.g., weight determined by sensors) is inputted in a control algorithm resident upon a microprocessor disposed within the sensing and diagnostic module in order to determine a desired deployment scheme for the inflatable cushion. For example, the data inputs when compared to a look up table stored in the memory of the microprocessor or other readable format will allow the algorithm to determine whether a full deployment or partial deployment of the airbag is desired (e.g., tailoring of the airbag module by activating or not activating a system designed to modify the cushion deployment characteristics).
The continuous sampling of the various sensors allows the sensing and diagnostic module to be provided with various inputs before an activation event (deployment) occurs. It is noted that the airbag inflation system of the present disclosure is contemplated for use with any combination of the aforementioned sensors and it is not intended to be limited by the specific types of sensors discussed above.
The seat position sensor detects the position or distance of seating structure 12 with respect to air bag module 14. Similarly, the optical scanner 28 can be used to detect the position of seating structure 12. The load sensor 30 is disposed within the seating structure 12 and can be used to detect the load on the seating structure. Thus, sensor 30 is capable of detecting the specific weight or load on a portion of seating structure 12. The seat recline sensor 32 can be used to detect the degree or angle to which an upper or back portion of the seating structure 12 is reclined or positioned with respect to a lower or seat portion of seating structure 12. The seat belt use detection sensor 34 can determine whether the seat belt 36 is secured (e.g., buckled is inserted into its corresponding clasp). The seat belt tensioning sensor, alone or in combination with the load sensor 30, can also be used to determine the load on the seating structure 12.
In accordance with an exemplary embodiment of the present invention and referring now to
In accordance with an exemplary embodiment, the unobstructed deployment of member 40 will cause a sensing device 46 to provide a signal to the sensing and diagnostic module or directly to the inflator. It is also noted that sensing device 46 may be used with any of the aforementioned sensors to provide inputs or signals to the sensing and diagnostic module or alternatively sensing device 46 may be the only device used to determine whether a second stage of the inflator is to be activated. In accordance with an exemplary embodiment the signal generated by sensing device 46 is provided to the sensing and diagnostic module for use in control logic wherein the sensing and diagnostic module provides an activation signal to the second initiator if the required signals are received by the sensing and diagnostic module.
In an exemplary embodiment, the inflator is a dual stage inflator having a first initiator for providing a first low inflation stage and a second initiator for use with the first initiator in order to provide a second inflation stage. In an exemplary embodiment the first initiator and the second initiator are pyrotechnic squibs that fire in response to an activation signal. Of course, other equivalent devices are contemplated to be within the scope of the present invention. In one exemplary embodiment, the second inflation stage provides a higher level of inflator output to the inflatable cushion than the first inflation stage. An example of the inflator output or pressures provided by only the first initiator are approximately 227 kilopascal (kPa), measured in a 60 liter tank, while the inflator output or pressure provided by only the second initiator are 432 kPa for a total combined pressure of 615 kPa. Such a dual stage inflator is designated as (615kPa/227 Kpa) which means if the primary initiator or first initiator is fired 227 kPa will be generated in the 60-liter tank and if both the primary and secondary are fired 615 kPa will be generated in the 60-liter tank. Of course, it is understood that the pressures (e.g., inflator gas output) associated with the first and second initiators may vary to levels greater and less than the aforementioned values. In addition, and in alternative exemplary embodiments the pressures provided by the first initiator and the second initiator may be equal or alternatively the pressures provided by the first initiator may be greater than the second initiator.
The variation of the inflator output provided by the first and second initiators and resulting inflating force of the inflating cushion may ultimately depend upon a variety of factors including the location of the airbag module within the vehicle and the possible locations of the vehicle seat. In an exemplary embodiment, the second inflation stage is provided to fully inflate the inflatable cushion. The gas volume delivered to the cushion (at a certain temperature and pressure) determines, in part, the force an inflating cushion will generate. Accordingly, the amount of force generated by the inflating cushion depends in part on the available volume as well as the inflator output and time after initial inflator activation. Exemplary embodiments of the present invention are directed to a deployable member disposed within or adjacent to the inflatable cushion. The deployable member will be inflated when an activation signal is sent to the first initiator and the deployable member will provide an activation signal to the second initiator if the inflatable member is able to deploy in an un-obstructed manner. If, however, the deployable member does not deploy in an un-obstructed manner no activation signal will be sent to the second initiator and only the first initiator will be fired.
The air bag module includes an outer housing 16 for mounting to or proximate to an instrument panel or interior surface of a vehicle by suitable means such as fasteners. Of course, the module is contemplated for mounting to other structures in the vehicle. The housing is made of an easily molded or extruded rigid material such as plastic, steel, aluminum etc. As will be described in detail below, air bag module 14 comprises means to customize or tailor the inflation level of the inflatable cushion 20. The inflation level is commensurate with unobstructed deployment of the inflatable cushion. More specifically, and in accordance with an exemplary embodiment, deployable member 40 will deploy outwardly away from air bag module 14 in a first direction defined generally by arrow 48. Once the deployable member reaches a full deployment defined by a distance “X” away from the airbag module, the fully and unobstructed deployment of deployable member 40 will cause sensing device 46 to generate a signal. The signal will indicate that deployable member has fully deployed or is unobstructed and the signal will cause second initiator to fire thereby initiating the second stage of inflation wherein the inflatable cushion will reach its full deployment configuration.
In accordance with an exemplary embodiment, deployable member 40 will be deployed with gas generated by the first low stage of inflation, which in one embodiment comprises approximately 30 percent of the overall inflator output generated by the inflator when both initiators are fired. Of course, the amount of inflator output corresponding to the first low inflation stage might vary to be greater or less than the aforementioned values. For example, the first low stage of inflation may comprise greater or less than 30 percent of the overall inflation output generated by the inflator if both initiators are fired. Other percentages include, but are not limited to, 50 percent of the overall inflation output of both initiators or, if applicable, greater than 50 percent of the overall inflation output or pressures provided by both initiators the inflator.
Referring back now to
As illustrated in
Referring now to
In accordance with an exemplary embodiment of the present invention, deployable member 40 provides a proximity sensor that is fully deployed when a first stage of the inflator is activated. In accordance with an exemplary embodiment, this occurs approximately 5 ms after the initial activation of the inflator. At approximately 10 ms after the initial activation of the inflator, and if sensing element 62 provides the appropriate signal, the second stage is fired wherein full deployment of the inflatable cushion occurs. It is, of course, understood that the aforementioned time periods are provided as non-limiting examples and the present invention is intended to be used with time periods greater or less than the aforementioned values. In addition, it is also understood that the microprocessor of the sensing and diagnostic module may, in an alternative embodiment, have logic for determining and providing the time delays between the first and second stages of inflation, wherein such timing or time periods between the first stage and the second stage may wary the total outputs of the initiators and the inflator.
In summation and in accordance with an exemplary embodiment illustrated in
The deployable member travels very fast to give a signal in under 5 ms this approach allows a very low first inflation stage to be used (e.g., 30% or less of the total inflation) as well as a very fast enable decision for the second stage that allows the airbag inflation to “catch up” for in-position occupants (e.g., 7 ms the signal is received and the second stage is fired), wherein the cushion fills normally with a fabric flap closing over the opening provided for the deployable member. The foam projectile is shaped like a mushroom to provide a blunt contact surface.
Referring now to
For example, another means for determining if the plate element has traveled its full stroke corresponding to unblocked deployment would be to couple the plate element to a conductive member, wherein the conductive member is configured to break or tear when the plate element reaches is fully deployed position. Once broken, the conductive member will no longer provide an electrical path between a first resistor and a second resistor, which are connected in parallel by electrical connectors. Accordingly, when the conductive member provides an electrical path between the first resistor and the second resistor a known resistance is provided. However, when plate element reaches an unobstructed deployment configuration, a force is applied to the conductive member such that the conductive path between the first resistor and the second resistor is no longer available. Accordingly, the resistance encountered by the electrical connectors will be equal to that of the second resistor. Therefore, control logic of the sensing and diagnostic module can be easily configured to determine whether the conductive member has been severed. For example, if each of the resistors has the same resistance, severing of the conductive member will cause the resistance to double. In addition, sensing and diagnostic module can easily determine whether the power has been cut or there is a short-circuit in the system. In each of these cases the control logic of the sensing and diagnostic module will be configured to provide an appropriate output signal.
Alternatively, an optical sensor 96 may be positioned to detect the presence or lack thereof of the piston or the central member within the plenum. For example, optical sensor 96 is positioned to detect light from a light source 85 positioned to provide a detectable light source that passes through a plurality of openings 87 in the central member wherein a portion 89 of the central member located proximate to the piston has no openings thus, no light can pass therethrough and be sensed by the optical sensor, once the central portion is fully extended from the housing. Alternatively, the piston itself may provide the necessary means to block the light being detected by the optical sensor. Accordingly, the lack of detected light by the optical sensor will provide a signal indicative of the deployment of the deployable member. Of course, the aforementioned example is provided as a non-limiting example and other configurations are contemplated. For example, sensor 96 may comprise an internal light source that is passed through openings 87 and reflected back to the sensor.
Another alternative sensing device would comprise a Hall effect sensor positioned at the location depicted by box 96 wherein a magnet is located at portion 89 or on piston 88 and the Hall effect sensor detects the magnetic field of the magnet once the deployable member is fully deployed and a signal is generated. As illustrated and in accordance with an exemplary embodiment, the plate element is a flexible low mass plastic plate with large holes, which in accordance with an exemplary embodiment weighs less than 20 grams. Of course, and if applications required the plate element may weigh more than 20 grams. If the deployment is obstructed, the plate will contact the occupant. The low mass of the plate will have a negligible effect due to contact with the occupant. An exemplary configuration for this embodiment to integrate the same with a mid-mounted airbag module, wherein this configuration allows the plate element to be pushed through a horizontal styling gap above or below the deployable door of the airbag module.
In an alternative embodiment the housing and plate element may comprise a completely separate unit located at a position remote from the airbag module housing wherein the airbag module has a unique orientation with respect to the vehicle interior (e.g., a top mounted airbag modules). In this case a styling gap above a glove box door can be utilized for deployment of the plate element. In accordance with an exemplary embodiment, the plate is designed to push with a maximum force of 500 Newtons on a close proximity occupant. Of course, and as applications require forces greater than 500 Newtons may be provided. This force will move the sensor into a final position in under 5 ms and also should provide some discrimination between an occupant's hand and other body portions. For example, an unsupported hand should be pushed out of the way by the plate element allowing for deployment of the inflatable cushion. A head or chest will have enough mass to remain in place and block the plate sensor.
An example of a deployment sequence with the embodiment of
If an occupant or other object is in close proximity to the airbag module the same will block the motion of the plate sensor. An example of this sequence is as follows: the crash sensor initiates the plate sensor squib, gas from the squib is used to push the sensor plate through a horizontal styling gap in the instrument panel and the plate is blocked by the occupant or other object and never reaches the end of travel. In this situation the electrical connection is not broken and the airbag controller does not receive the “zone is clear” signal. Thus, the airbag deployment is suppressed.
Referring now to
In this embodiment, the inflator further comprises a plenum 106 and rotary valve assembly 108, wherein the plenum further comprises a first plurality of plenum ports 110, which are positioned to be in fluid communication with the inflatable cushion (e.g., provide an inflation force to the cushion), a second plurality of plenum ports 112, which are positioned to be in fluid communication with an exterior of the housing (e.g., allow for venting of the inflation force as opposed to directing it to the inflatable cushion), and a conduit or tube 114 providing fluid communication between the plenum and the housing 102 (e.g., drive the plate out of the housing). In addition, the rotary valve assembly comprises a rotatable valve member 116 configured to be rotatable received within plenum 106. In accordance with an exemplary embodiment rotatable valve member 116, will have a plurality of openings 118 configured to align with the second plurality of openings of the plenum in a first position and a plurality of openings 120 configured to align with the first plurality of openings of the plenum in a second position, wherein the plurality of openings 118 are aligned with the second plurality of openings of the plenum in a default positioned such that the inflator and the airbag module is configured to allow a portion of the inflation gas to exhaust out of the housing during a first stage of inflation. In accordance with an exemplary embodiment plenum 106 will have rotation limit bolts 117 or equivalent items in order to provide a means for limiting the rotation of valve member between the first position and the second position or in other words the bolts or equivalent items will protrude into the plenum in order to provide stops for the valve member. In addition, bolts 117 will ensure that either the first plurality of openings or the second plurality of openings are open to allow inflation gas to exhaust from the plenum.
In accordance with an exemplary embodiment un-obstructed deployment of the plate element will cause the rotatable valve member to rotate within the plenum wherein the plurality of openings 118 are no longer aligned with the second plurality of openings in the plenum and the plurality of openings 120 are now aligned with the first plurality of openings in the plenum thereby redirecting the inflation gas into the inflatable cushion. In accordance with an exemplary embodiment rotation of the rotatable valve member is facilitated by securing a cable 122 to a rearward end of the plate element at one end and a portion of the rotatable valve member at the other wherein the cable travels through the conduit providing fluid communication between the housing and the plenum.
A deployment sequence of this embodiment is as follows: a collision sensor initiates the airbag inflator (similar to current systems) wherein gas from the inflator is captured in the plenum surrounding the inflator and forced out the back of the module through a row of holes in the rotary valve member and the housing. The gas also travels down the conduit into a chamber around the plate sensor, wherein the pressure in the chamber is increased and the plate sensor is forced out through a horizontal styling gap in the instrument panel. When the plate reaches the end of the travel (approximately 100 mm of course, and as applications require the distance may be greater or less than 100 mm), the cable becomes taut and rotates the valve body in the inflator plenum. This rotation closes the ports venting the gas through the back portion of the housing while simultaneously opening ports into the inflatable cushion. The remaining gas is then directed into the inflatable cushion causing a normal deployment. In accordance with an exemplary embodiment, the plate movement and valve rotation occur will occur within 10 ms so that very little gas is expelled through the rear portion of the housing when unobstructed deployment of the plate number occurs.
In accordance with an exemplary embodiment and when a close proximity occupant is positioned to block the movement of the plate sensor away from the housing to block deployment sequence occurs. A blocked deployment sequence can be described as follows: the collision sensor initiates the airbag module inflator wherein gas from the inflator is captured in the plenum surrounding the inflator and forced out the back of the module through a row of holes in the rotary valve and the housing. The gas also travels down the tube and pushes on the plate sensor until the plate sensor is forced from a horizontal styling gap in the instrument panel. The plate is then blocked by the occupant and never reaches the end of travel thus, the cable does not become taut and the valve body is not rotated and the remaining gas is vented out of the back of the airbag module. In this scenario, the airbag deployment is suppressed because the cushion never receives any inflation gas.
In accordance with an exemplary embodiment, the plate sensor is a flexible low mass plastic plate with a plurality of holes wherein the total weight of the plate sensor is <20 grams of course, and as applications require, plate sensors greater than 20 grams are contemplated. If the deployment area is obstructed, the plate will contact the occupant or other object wherein the low mass of the plate will have a negligible effect due to contact with the occupant. An exemplary configuration for this embodiment to integrate the same with a mid-mounted airbag module, wherein this configuration allows the plate element to be pushed through a horizontal styling gap above or below the deployable door of the airbag module. This configuration also allows the rotary valve plenum and plate housing to be integrated into the airbag canister with an aluminum extrusion design. The plate is designed to push with a maximum force of 500 Newtons on a close proximity occupant. This force will move the sensor into final position in less than 5 ms and also should provide some discrimination between an occupant's hand or other body portion wherein an unsupported hand will be pushed out of the way by the sensor allowing normal deployment. In contrast, an occupant's head or chest will have enough mass to remain in place and block the plate sensor.
Non-limiting examples of the time of travel of the plate in this embodiment are as follows: if unobstructed, the plate element will reach its end of stroke in approximately 8 ms after the firing of the inflator and the rotary inflation valve will be turned by the movement of the plate and all of the remaining inflation gas will be directed into the cushion. Thereafter, and at approximately 10 ms after the initial firing, a second stage, if needed and if applicable (e.g., dual stage inflator etc.) of the inflator is fired.
On the other hand, if there is an obstruction the plate element is blocked and this will occur at approximately 4 ms after the initiator has been fired (e.g., plate does not deploy fully out of the housing) and all remaining inflator gas is exhausted behind instrument panel regardless of whether a second stage is available and employed. It is, of course, understood that the aforementioned time sequences are merely provided as non-limiting examples, wherein values greater or less than those mentioned herein are contemplated and exemplary embodiments of the present invention are not intended to be limited by the same.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
