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Title:
UNIVERSAL ROLLER SWAGING MACHINE WITH TOOL WEAR MONITOR AND METHOD FOR SWAGING WORK PIECES TOGETHER
Document Type and Number:
WIPO Patent Application WO/2014/168827
Kind Code:
A1
Abstract:
A roller swaging machine is provided for swaging first and second work pieces together. The roller swaging machine may include a base, a work piece support assembly, a tool A roller swaging machine (10) is provided for swaging first and second work pieces together. The roller swaging machine may include a base (12), a work piece support assembly (20), a tool carriage assembly (30), a spline feed assembly (40), and a linear sensor (48). In an embodiment, a tool carriage assembly (30) may be configured to support an expander tool (60) having a tapered mandrel (62), the spline feed assembly (40) may be configured to be coupled to the tapered mandrel (62) of the expander tool (60), and the linear sensor (48) may be configured to measure axial movement of the tapered mandrel (62). A method for swaging work pieces together is also disclosed.

Inventors:
ARAVINDAN ANAND (IN)
NAGPURE SAMEER SURESHRAO (IN)
SPINK KENNETH MAYNARD (US)
SURESH SRINIVAS B (US)
Application Number:
PCT/US2014/032973
Publication Date:
October 16, 2014
Filing Date:
April 04, 2014
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
EATON CORP (US)
International Classes:
B21D41/02; B21D39/10; B21D39/20
Foreign References:
US20120167372A12012-07-05
JPH03207537A1991-09-10
DE102005029680A12007-01-04
US20070204666A12007-09-06
Other References:
None
Attorney, Agent or Firm:
GUENTHER, John, P. (39577 Woodward Avenue Suite 30, Bloomfield Hills MI, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A roller swaging machine comprising:

a base;

a work piece support assembly supported on or above the base;

a tool carriage assembly supported on or above the base, the tool carriage assembly configured to support an expander tool having a tapered mandrel;

a spline feed assembly supported on or above the base, the spline feed assembly configured for connection to the tapered mandrel of the expander tool; and

a linear sensor configured to measure axial movement of the tapered mandrel.

2. The roller swaging machine of claim 1, wherein the work piece support assembly interchangeably supports a work piece adaptor configured to secure a first work piece relative to a second work piece.

3. The roller swaging machine of claim 1, wherein the tool carriage assembly is supported for movement along the base.

4. The roller swaging machine of claim 2, wherein the tool carriage assembly includes a locking mechanism configured to secure the tool carriage assembly in a selectable position relative to the base.

5. The roller swaging machine of claim 1, wherein the tool carriage assembly interchangeably supports a tooling adaptor configured to support the expander tool.

6. The roller swaging machine of claim 1, wherein the spline feed assembly is supported for movement along the base.

7. The roller swaging machine of claim 6, wherein the spline feed assembly includes a locking mechanism configured to secure the spline feed assembly in a selectable position relative to the base.

8. The roller swaging machine of claim 1, wherein the linear sensor is a linear variable differential transducer.

9. The roller swaging machine of claim 1, including an on-board computer or processor configured to control axial movement of the tapered mandrel based on an input from the linear sensor.

10. The roller swaging machine of claim 9, wherein the on-board computer or processor is configured to control radial expansion of the rollers based on the axial movement of the tapered mandrel measured in connection with the linear sensor.

11. A method for swaging work pieces together comprising:

installing an expander tool on a tool carriage assembly of a roller swaging machine, the expander tool including a tapered mandrel supported for axial movement relative to a plurality of rollers;

coupling a spline feed assembly provided on the roller swaging machine to the tapered mandrel of the expander tool;

installing a first work piece relative to a second work piece on a work piece support assembly provided on the roller swaging machine;

calibrating a linear sensor provided on the roller swaging machine to determine a relationship between axial movement of the tapered mandrel and an instantaneous outer diameter of the rollers; and

swaging the first and second work pieces to a post swage inner diameter (PSID) based on the axial movement of the tapered mandrel.

12. The method of claim 11, including calculating a target PSID by adjusting a desired PSID of the first and second work pieces, and swaging the first and second work pieces to the target PSID.

13. The method of claim 12, wherein the calculating the target PSID includes:

providing a desired PSID;

providing at least one actual dimension of the first or second work piece;

adjusting the desired PSID based on the actual dimension of the first or second work piece to achieve a corrected PSID; and

adjusting the corrected PSID based on a set or pre-determined spring back correction factor of the first and second work pieces.

14. The method of claim 13, wherein the actual dimension of the first or second work piece can be at least one of a wall thickness of the first work piece, an outer diameter of the first work piece, and an inner diameter of the second work piece.

15. The method of claim 13, wherein the desired PSID is adjusted by an amount that the actual dimension varies from a pre-determined nominal dimension of the first or second work piece.

16. The method of claim 13, wherein the spring back correction factor can be determined by initially swaging the first and second work pieces to the target PSID, measuring the actual PSID, and calculating a difference between the target PSID and the actual PSID.

17. The method of claim 11, wherein the calibrating the linear sensor includes:

installing a first ring gage with a first diameter on the work piece support assembly; measuring the axial movement of the tapered mandrel that is required for the rollers to achieve the first diameter;

installing a second ring gage with a second diameter on the work piece support assembly; measuring the axial movement of the tapered mandrel that is required for the rollers to achieve the second diameter; and

determining a relationship between the axial movement of the tapered mandrel and the outer diameter of the rollers.

18. The method of claim 11 , including monitoring an actual PSID of the swaged work pieces to determine potential tooling wear on the expander tool.

19. The method of claim 17, wherein the monitoring for potential tooling wear on the expander tool includes:

measuring an actual PSID of the swaged work pieces;

comparing the target PSID with the actual PSID of the swaged work pieces; and notifying an operator if the target PSID exceeds the actual PSID by a pre-determined threshold.

20. The method of claim 11 , including monitoring a torque being applied to the tapered mandrel to ensure that the torque is within a pre-determined threshold to ensure a quality swage and detect failure modes.

Description:
UNIVERSAL ROLLER SWAGING MACHINE WITH TOOL WEAR MONITOR AND METHOD FOR SWAGING WORK PIECES TOGETHER

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Patent Application No. 13/861,872, filed April 12, 2013, which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

[0002] The present disclosure relates to roller swaging machines, including a roller swaging machine that is configured to calculate a target post swage inner diameter (PSID), swage work pieces to the target PSID, and monitor expander tooling wear.

BACKGROUND

[0003] Roller swaging machines are commonly used to secure an end fitting onto a tube using a mechanical connection. For example, the end fitting is loosely placed over an end of the tube, and an expander tool is inserted within the end of the tube. The expander tool includes a plurality of rollers that are supported around a tapered mandrel. The tapered mandrel is rotated and advanced along its axis relative to the rollers. Advancement of the tapered mandrel causes the rollers to radially expand and engage an inner circumference of the tube. As a result, the rollers force the tube to radially expand into contact with the end fitting, thereby forming a mechanically sealed connection between the tube and the end fitting.

[0004] However, consistent quality of swaged connections can be somewhat difficult to achieve as a result of varying dimensions of work pieces (i.e., tolerances) and tooling wear of the tapered mandrel and rollers. As such, it would desirable to provide a roller swaging machine that is configured to calculate a target post swage inner diameter (PSID) based on the actual dimensions of the work pieces, swage the work pieces to the target PSID, and monitor expander tooling wear.

SUMMARY

[0005] A roller swaging machine is provided for swaging first and second work pieces together. The roller swaging machine may include a base, a work piece support assembly, a tool carriage assembly, a spline feed assembly, and a linear sensor. In an embodiment, a tool carriage assembly may be configured to support an expander tool having a tapered mandrel, the spline feed assembly may be configured to be coupled to the tapered mandrel of the expander tool, and the linear sensor may be configured to measure axial movement of the tapered mandrel.

[0006] Various aspects of the present disclosure will become apparent to those skilled in the art from the following detailed description of the various embodiments, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of an embodiment of a roller swaging machine in accordance with aspects of the present disclosure.

[0008] FIG. 2 is an enlarged perspective view of an embodiment of a work piece support assembly that may be used with a roller swaging machine such as generally illustrated in FIG. 1.

[0009] FIG. 3 is an enlarged perspective view of an embodiment of an expander tool carriage assembly that may be used with a roller swaging machine such as generally illustrated in FIG. 1.

[0010] FIG. 4 is an enlarged perspective view of an embodiment of a spline feed assembly that may be used with a roller swaging machine such as generally illustrated in FIG. 1.

[0011] FIG. 5 A is a block representation generally illustrating an embodiment of an expander tool wear monitoring system that may be used with a roller swaging machine such as generally illustrated in FIG. 1, wherein the expander tool is shown in a first position.

[0012] FIG. 5B is a block representation generally illustrating the expander tool wear monitoring system as generally illustrated in FIG. 5A, wherein the expander tool is shown in a second position.

[0013] FIG. 6 is a flow chart generally illustrating an embodiment of a method for swaging work pieces to a desired post swage inner diameter (PSID) that may employ a roller swaging machine such as generally illustrated in FIG. 1.

[0014] FIG. 7 is a flow chart generally illustrating an embodiment of a method for calculating a target PSID that may employ a roller swaging machine such as generally illustrated in FIG. 1.

[0015] FIG. 8 is a flow chart generally illustrating an embodiment of a method for monitoring expander tooling wear that may employ a roller swaging machine such as generally illustrated in FIG. 1. DETAILED DESCRIPTION

[0016] Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the invention will be described in conjunction with embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.

[0017] Referring now to the drawings, FIG. 1 illustrates an embodiment of a roller swaging machine 10 including aspects of the present disclosure. The roller swaging machine 10 can be used to swage a first work piece to a second work piece, thereby forming a mechanically sealed connection between the two work pieces. For example and without limitation, the first work piece may comprise a tube or the like, and the second work piece may comprise a sleeve, union, bulkhead fitting, flange, or other fitting. The swaged work piece may be suitable, for example and without limitation, in aircraft, space-craft, marine, industrial, and other high reliability applications.

[0018] As generally illustrated in FIG. 1, an embodiment of a roller swaging machine 10 may include a base 12. The base 12 can be a suitable support surface, such as a table top, bench, cart, or the like, and may be supported on a plurality of wheels if desired. The base 12 may include a set of guide rails 14, and the set of guide rails 14 may extend, for at least some distance, generally parallel with one another along a top surface of the base 12, a purpose of which will be explained below.

[0019] The roller swaging machine 10 may further include a work piece support assembly 20, a tool carriage assembly 30, and a spline feed assembly 40. In embodiments, the roller swaging machine 10 may also include a programmable logic controller (PLC) and a graphical user interface (GUI) 50. Aspects and features of the foregoing components are described further below. It should be fully appreciated, however, that the roller swaging machine is not limited to the illustrated embodiment, but may include any other components and/or configurations of components suitable for swaging work pieces together.

[0020] Referring now to FIGS. 1 and 2, the work piece support assembly 20 may be rigidly secured to the base 12. As more clearly shown in FIG. 2, the work piece support assembly 20 can include, among other components, a set of jaws 22 (or similarly functioning components) that are configured to interchangeably support a work piece adaptor 24. The jaws 22 may be actuated (i.e., opened and closed) by an automated system, which may include, for example, a hydraulic or pneumatic actuator. The jaws 22 may also be secured in a closed position by a suitable locking device, such as locking mechanism 26. The work piece adaptor 24 may, in turn, be configured to securely support first and second work pieces (which may be collectively referred to as "the work pieces") during the swaging process. The jaws 22 can be configured to support a variety of customized work piece adaptors 24 that, in turn, may be configured or designed for specific work pieces. The ability of the work piece support assembly 20 to support a variety of work piece adaptors 24 is a feature that can enable embodiments of a roller swaging machine 10 to be more universal. In other words, the roller swaging machine 10 can be used to swage work pieces having a variety of sizes and intended applications such as, for example and without limitation, fuel line fittings on the one hand and hydraulic tube fittings on the other.

[0021] Referring now to the embodiments illustrated in FIGS. 1 and 3, a tool carriage assembly 30 can be supported for linear movement along one or more guide rails 14 (collectively referred to as "guide rails") on the top surface of the base 12. The tool carriage assembly 30 can be selectively fixed in any position along the guide rails 14 by a locking mechanism including, but not limited to, a clamp 32 (see, e.g., FIG. 1). As more clearly illustrated in FIG. 3,

embodiments of the tool carriage assembly 30 may include a base 34 that can be configured to interchangeably support a tooling adaptor 36. For example and without limitation, the base 34 may comprise a generally U-shaped fixture; although, the base 34 may comprise other suitable support fixtures. The tooling adaptor 36, in turn, can be configured to securely support an expander tool. As explained in further detail below, embodiments of an expander tool may include a tapered mandrel that is supported for rotational and axial movement relative to a plurality rollers. In an embodiment, the tooling adaptor 36 may comprise a collar-style fixture; however, the adaptor may comprise other forms of suitable support fixtures. In embodiments, the tooling adaptor 36 may be removably secured to the base 34 in any suitable manner. The base 34 can be configured to support a variety of customized tooling adaptors 36 that may be designed for specific expander tools. The ability of the tool carriage assembly 30 to be moved along the guide rails 14 relative to the work piece support assembly 20 and the ability to support a variety of tooling adaptors 36 are features that, among other things, can help enable the roller swaging machine 10 to be more adaptable or universal in nature. [0022] Referring now to FIGS. 1 and 4, the spline feed assembly 40 can be supported for linear movement along guide rails 14 providing on an upper or top surface of the base 12. The spline feed assembly 40 can be selectively fixed in almost any position along the guide rails 14 by a locking mechanism, which may include, but is not limited to, a clamp 42. As generally illustrated in FIG. 4, an embodiment of a spline feed assembly 40 may include a motor 43, a gear box 44, a rotatable spline 45, and a spline coupler 46. The motor 44 can be configured to selectively rotate the spline 45 via the gear box 44, which in turn can rotate the spline coupler 46. The spline coupler 46 is configured to be connected to an end of the tapered mandrel on the expander tool for selective rotation and axial movement of the tapered mandrel. The spline feed assembly 40 may also be configured to move the spline coupler 46 in an axial direction, such as with a mechanical actuator. The ability of the spline feed assembly 40 to be moved along the guide rails 14 relative to the tool carriage assembly 30 is a feature that can enable embodiments of the roller swaging machine 10 to be more adaptable or universal.

[0023] The spline feed assembly 40 may also include a linear sensor 48. The linear sensor 48 can be configured to detect and measure the axial movement (e.g., a stroke length) of the tapered mandrel on the expander tool as it is advanced relative to the rollers, such as described further below. In an embodiment, the linear sensor 48 may comprise a linear variable differential transducer (LVDT). It should be appreciated, however, that the linear sensor 48 can, instead of or additionally, comprise another sensing or detection device that is capable of measuring the axial movement of the tapered mandrel. Some potential features or purposes of a linear sensor are discussed further below.

[0024] The roller swaging machine 10 may also include a programmable logic controller (PLC) or other type of on-board computer. In embodiments, the PLC can include a computing system that is capable of receiving inputs, performing computing functions, and providing outputs. The PLC may also include memory that is capable of storing information or data. A user interface, such as a graphical user interface (GUI) 50, may also be provided to, among other things, display information to an operator and/or to provide a means for an operator to input information into the PLC. The GUI 50 may comprise a touch screen interface or other suitable user interface. It should be fully appreciated that the roller swaging machine 10 may include various other electrical and/or computing components associated with a desired function or application. [0025] Referring now to FIG. 5A, a block representation of an embodiment of an expander tool 60 is generally illustrated. The illustrated expander tool 60 includes a tapered mandrel 62 and a plurality of rollers 64. The tapered mandrel 62 may be supported for axial movement relative to the rollers 64. The rollers 64 may be supported around an outer surface of the tapered mandrel 62 for rotational and radial movement relative to the tapered mandrel 62. In an embodiment, as the tapered mandrel 62 is advanced in an axial direction towards the rollers 64, the rollers 64 gradually expand outwardly in the radial direction due to (in conformance with) the tapered outer surface of the mandrel 62. As a result, a desired outer diameter of the expander tool 60 can be achieved by controlling the axial movement of the tapered mandrel 62. It should be appreciated that the radial expansion of the rollers 64 may be directly related or proportional to the axial movement of the tapered mandrel 62. Thus, the radial expansion of the rollers 64 can be determined from, or based upon, axial movement of the mandrel 62.

[0026] As briefly described above, a linear sensor 48 may be configured to detect and/or measure axial movement of the tapered mandrel 61. The linear sensor 48, therefore, can be configured or calibrated to help determine a direct relationship between axial movement of the tapered mandrel 62 and radial expansion of the rollers 64. In an embodiment, the linear sensor 48 can be calibrated by supporting a first ring gage 66 having a known first diameter on the work piece support assembly 20 (see, e.g., FIG. 1). The expander tool 60 may be inserted within the first ring gage 66 as if to perform a swaging process. The tapered mandrel 62 may be advanced until the rollers 64 radially expand and initially come into contact with an inner diameter of the first ring gage 66. The axial movement of the tapered mandrel 62 that is measured by the linear sensor 48 and the diameter of the first ring gage 66 may be stored, for example, in a PLC. Next, a second ring gage having a known second diameter may be supported on the work piece support assembly 20. Again, the expander tool 60 may be inserted into the second ring gage as if to perform a swaging process. The tapered mandrel 62 may be advanced until the rollers 64 radially expand and initially come into contact with an inner diameter of the second ring gage. The axial movement of the tapered mandrel 62 that is measured by the linear sensor 48 and the diameter of the second ring gage may be stored, for example, in a PLC. The PLC may then use the gathered data to determine a direct relationship between the axial movement of the tapered mandrel 62 and the outer diameter of the rollers 64. As a result, an instantaneous outer diameter of the rollers 64 can be determined from, or based upon, an axial movement of the tapered mandrel 62, which may be measured in connection with a linear sensor 48.

[0027] Referring now to FIG. 6, an embodiment of a method of swaging first and second work pieces to a desired post swage inner diameter (PSID) using a roller swaging machine of the type disclosed herein will be explained. In an initial step 70, desired external tooling can be mounted on the roller swaging machine 10. After the desired tooling is installed on the roller swaging machine 10, a GUI 50 may prompt the operator to select a mode of swaging. In an embodiment, the roller swaging machine 10 may be configured to swage in a "diameter control mode" or a "torque control mode." In a diameter control mode, the operator may enter a desired post swage inner diameter (PSID) and the roller swaging machine 10 may swage the work pieces until the desired PSID is reached or obtained. In a torque control mode, the operator may enter a desired torque and the roller swaging machine 10 may swage the work pieces until a desired torque on the spline 45 is reached or obtained. When a desired mode is selected, if desired, the other (non-selected) mode can be monitored by the PLC as a backup monitoring system or safety factor to protect the tooling and the swage limits. For example, if the diameter control mode is selected, a PLC may be configured to continue to monitor the torque on the spline 45 to ensure that the torque does not exceed a pre-determined threshold.

[0028] If the diameter control mode is selected, then a linear sensor 48 may then be calibrated at step 72, such as generally described above. After the linear sensor 48 is calibrated, a spring back correction factor may be set. The spring back correction factor may, for example, comprise the difference in a target PSID calculated by the roller swaging machine 10 (such as described below) and an actual PSID that may be measured (such as by an operator). Spring back may be a result of the resiliency in the material of the work pieces and can occur after the swaging process has been performed. In other words, if spring back is present, then the actual PSID may be less than the target PSID. To set the spring back correction factor, the operator may enter a target PSID into the system (e.g., into a GUI) and swage the work pieces. An operator can then measure or obtain an actual PSID and enter that into the system (e.g., into a GUI). The difference between the target PSID and the actual PSID can provide a relevant spring back correction factor.

[0029] After the set up and calibration steps are complete, a GUI (such as GUI 50) may prompt an operator to input preliminary swage information. Such information may include, but is not limited to, a desired PSID, an actual outer diameter of a first work piece (e.g., tube), an actual wall thickness of a first work piece (e.g., tube), and/or an actual inner diameter of a second work piece (e.g., end fitting). Based on the information that is inputted into the system, a PLC can be configured to calculate a target PSID at step 74, such as will be generally explained below. The roller swaging machine 10 may then swage the work pieces to the target PSID, at step 76, by sensing and utilizing a stroke length of the tapered mandrel 62. Swaging the work pieces to the target PSID can ultimately achieve the desired PSID.

[0030] After the work pieces have been swaged, in embodiments, the system may prompt an operator to measure the actual PSID of the swaged work pieces and enter the dimension into the system. The system can display the acceptable range for the target PSID and enable the operator to accept, reject, or re-swage the work pieces. A PLC may also be configured to store the swaging data for any or all swage operations that are performed. These steps can be repeated any number of times for additional swages.

[0031] Referring now to FIG. 7, an embodiment of a method of calculating a target PSID will be described. As noted above, the system (e.g., a GUI) may prompt an operator to input preliminary swage information. For example, a GUI 50 can prompt an input of a desired PSID at step 80. The system may then prompt an input of the actual dimensions of the work pieces at step 82. Such dimensions can include the outer diameter of the first work piece, the wall thickness of the first work piece, the inner diameter of the second work piece, and/or a spring back factor.

[0032] A corrected PSID may then be calculated by the PLC at step 84. The corrected PSID is the desired PSID entered at step 80, which may then be corrected based on the actual dimensions that influence groove fill entered at step 82. If other than nominal values are entered for the actual dimensions at step 82, then the desired PSID may be adjusted accordingly. The desired PSID is adjusted by the amount above or below nominal in order to achieve a swaged connection that would be equivalent to a swaged connection using work pieces having nominal dimensions. For example, if the outer diameter or the wall thickness of the first work piece (e.g., tube) is larger than nominal, the then desired PSID will be reduced by the amount above nominal to obtain the corrected PSID. If the inner diameter of the second work piece (e.g., end fitting) is larger than nominal, then the desired PSID will be increased by the amount above nominal to obtain the corrected PSID. Conversely, if the inner diameter of the second work piece (e.g., end fitting) is smaller than nominal, then the desired PSID will be decreased by the amount below nominal to obtain the corrected PSID.

[0033] The target PSID may then be calculated by the PLC at step 86. To calculate the target PSID, the corrected PSID may be adjusted by a spring back correction factor. For example, when a value is entered for a spring back correction factor, the corrected PSID can be increased by that amount to compensate for spring back. As described above, swaging the work pieces to the target PSID ultimately achieves a desired PSID.

[0034] Referring now to FIG. 8, an embodiment of a method of monitoring expander tooling wear will be generally explained. At step 90, the linear sensor 48 may be calibrated to determine a direct relationship between axial movement of the tapered mandrel 62 and radial expansion of the rollers 64, such as previously described. A PLC may then calculate a target PSID at step 92, for example, as explained above. At step 94, the work pieces can then be swaged to a target PSID based on the mandrel stroke, which can be measured by the linear sensor 48. The system (e.g., GUI 50) may prompt a measurement by the operator of the actual PSID of the swaged work pieces and enter or intake the dimension. The actual PSID of the swaged work piece may then be compared to the target PSID at step 96. If the target PSID exceeds the actual PSID by a pre-determined threshold, then the PLC may be configured to provide an alert and/or notify the operator at step 98 to inspect the expander tool 60 for potential tooling wear 68, such as is generally illustrated in FIGS. 5 A and 5B. The tool monitoring features enables a maximum number of swages while eliminating or substantially reducing the potential that work pieces are swaged with a damaged or worn expander tool 60. A relationship between the torque and the mandrel stroke may also be established for creating upper and lower limits that differentiates an acceptable swage from an unacceptable (or "bad") swage. This relationship can be also be used to alter the operator of other failure modes such as, for example, if the jaws 22 are not securely locked (i.e., if the PSID is achieved but the torque is below a predetermined limit, an error notification may be provided to the operator describing such a failure).

[0035] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and various modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.