Abstract:
A device and method for controlling strain in a transmission line such as a power or signal transmitting wire, cable or other conduit. The device includes a body having at least one cavity formed therein for receipt of at least a portion of a transmission line. Multiple openings formed in the body allow the transmission line to extend from the at least one cavity and external to the body. The at least one cavity is defined to include a peripheral boundary formed at least partially by a first substantially linear wall and a second opposing wall which deviates from the first wall, thereby forming a deviation path for the transmission line disposed therein. A cover may be provided to cooperatively mate with the body such that it conceals the cavity or cavities formed therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a divisional of application Ser. No. 10/056,943, filed Oct. 25, 2001, pending. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to the attachment of wires, cables or other conduits to flexible structures, or between multiple structures expected to exhibit relative motion therebetween, and, more particularly, to the employment of such wires, cables or conduits in high strain-inducing environments while protecting the wires, cables or conduits from such strain and while also providing protection from dynamic or other natural and induced environments.  
         [0004]     State of the Art  
         [0005]     Wires, cables and other conduits, referred to collectively herein as transmission lines, are conventionally used to transmit power or signals in various applications. Such transmission lines may transmit power or signals, for example, electrically, hydraulically or pneumatically. Often such transmission lines are attached to an associated structure for which the transmission lines are carrying power or are communicating signals. For example, transmission lines are conventionally found in, and are in some manner attached to, buildings, cars, transport vehicles, railway cars, aerospace vehicles and numerous other structures to deliver power to, or communicate with, various components of such structures.  
         [0006]     In numerous applications, the structure to which the transmission lines are attached may experience forces or motions which place a strain on the transmission lines. Alternatively, the transmission lines may be coupled between multiple structures, or between multiple components of a single structure, wherein the relative movement between the multiple structures may induce strain therein.  
         [0007]     For example, transmission lines are conventionally attached to a rocket motor&#39;s casing for powering and controlling components associated with the rocket motor. A conventional rocket motor may include a casing fabricated from a composite material formed of fibers or filaments and a bonding agent and which is configured to accommodate a relatively large amount of strain during operation of the rocket motor. For example, operational stresses applied to the casing of a conventional rocket motor may result in a strain exhibited as an elongation of the casing of up to 2%. Additionally, pressure from within the rocket motor may cause a radial deformation of the casing. Transmission lines conventionally attached to such a casing may experience mechanical degradation and potential failure when exposed to high-strain magnitudes.  
         [0008]     In an effort to reduce the strain experienced by transmission lines in such service, various techniques and systems have been employed. However, such conventional techniques and systems are expensive and require an extensive amount of time and labor to install. For example, a given rocket motor may require upwards of 2,500 individual parts, including various brackets, clamps and covers, to install the requisite raceways which house transmission lines associated with the rocket motor. Additionally, installation of such a raceway system may require several weeks of intensive labor.  
         [0009]     Referring to  FIG. 1 , a cross section of such a prior art raceway  100 , coupled to a rocket motor  102 , is shown. The raceway  100  is configured to house multiple transmission lines  104 , which transmission lines may include various configurations and sizes of wires, cables and conduits. The transmission lines  104  may even include destruct charges  104 A which are configured to destroy the rocket motor  102  in the case of an errant rocket path, as will be appreciated by those of ordinary skill in the art.  
         [0010]     Clamping mechanisms  106  may be employed to bundle multiple transmission lines  104  together. The transmission lines  104  and/or the clamping mechanisms  106  may be coupled to various brackets  108 , which may in turn be attached to the casing  110  of the rocket motor  102  by means of fasteners or through use of an adhesive. Covers  112  of various configurations serve to conceal and protect the transmission lines  104  from an external atmosphere and provide a more aerodynamic profile on the rocket motor exterior.  
         [0011]     Numerous design requirements must be met in implementing the raceway  100  with the rocket motor  102 . For example, each bracket  108  may need to be individually tested upon assembly. Any adhesive or shear ply used in the installation of the raceway  100  must be able to withstand local elongation transferred from the rocket motor casing  102 . Further, the raceway covers  112  must be designed to slide relative to other components during operation of the rocket motor  102  so as to prevent mechanical damage to themselves or other components of the raceway  100 . For example, slots may be formed in the covers  112 , allowing fasteners to be placed therethrough, thereby maintaining the cover in a substantially fixed radial position relative to the rocket motor  102 , but allowing the covers  112  a limited amount of longitudinal movement relative to the rocket motor  102 , the brackets  108  and other components attached thereto.  
         [0012]     Additionally, the raceway  100  must meet pressure and thermal design criteria. For example, the raceway  100  must be able to withstand both internal and external pressures which may result in a differential pressure of up to  10  pounds per square inch, or higher. In order to prevent thermal degradation, all covers may include a cork thermal protection which is conventionally manually applied. Further, a room temperature vulcanizing (RTV) sealant is conventionally applied along all edges during assembly. Also, air flow and temperature within the raceway  100  must be considered as it is often desirable to limit the exposure of the transmission lines  104  to hot air or other gases which may be present within the raceway  100 .  
         [0013]     Thus, as can be seen, a great deal of design, preparation, manufacture and assembly work goes into installing transmission lines on a rocket motor to ensure proper operation.  
         [0014]     As mentioned above, installation of transmission lines on or between other structures may experience similar difficulties. For example, relative movement between a truck and a trailer (or between two railway cars) may induce unwanted strain in transmission lines coupled therebetween. Additionally, pressurized pipelines, rotating or moving aircraft surfaces and earthquake-proof buildings, to name a few examples, may induce unwanted strains in transmission lines associated therewith and extending between mutually movable components, or components which elongate in various directions under applied stresses.  
         [0015]     In view of the shortcomings in the art, it would be advantageous to provide a device and a method for attaching transmission lines to or between structures and which allow the structure to experience relatively high strains, including strains induced by stretching, compression, or other flexure, while maintaining the associated transmission lines in a low-strain environment. Such a device and method might also desirably provide thermal and environmental protection to the transmission lines.  
         [0016]     It would be additionally advantageous to provide a device and a method for controlling the strain experienced by transmission lines which is simple and relatively inexpensive to fabricate and install and/or implement. It would also be advantageous to provide such a device and a method which is easily tailored to specific applications and installations.  
       BRIEF SUMMARY OF THE INVENTION  
       [0017]     In accordance with one aspect of the invention, a strain control device is provided. The strain control device includes a body having a first end and a second end. A first opening is defined in the first end and a second opening is defined in the second end. At least one cavity is formed in the surface of the body such that the at least one cavity is in communication with the first and second ends. A periphery of the at least one cavity is defined, at least partially, to include a first substantially linear wall and a second opposing wall which deviates from the first substantially linear wall. The second opposing wall may include a curved configuration with at least a portion exhibiting a constant radius.  
         [0018]     In accordance with another aspect of the invention, another strain control device is provided. The strain control device includes a body having a first end and a second end. A first plurality of openings is defined in the first end and a second plurality of openings is defined in the second end. A plurality of cavities is formed in a surface of the body, with each cavity of the plurality being in communication with an opening of the first plurality of openings and an opening of the second plurality of openings. Each of the plurality of cavities also includes a periphery which is at least partially defined by a first substantially linear wall and a second opposing wall which deviates from the first substantially linear wall.  
         [0019]     In accordance with another aspect of the invention, another strain control device is provided. The strain control device includes a body having a first end and a second end. At least one cavity is formed in the body between the first end and the second end. The at least one cavity is configured to receive at least a portion of a transmission line therein and defines a deviation path for that portion of the transmission line.  
         [0020]     In accordance with another aspect of the invention, a rocket motor is provided. The rocket motor includes a rocket casing and a body attached to a surface of the rocket casing. The body includes a first end and a second end with a first opening being defined in the first end and a second opening defined in the second end. At least one cavity is formed in a surface of the body, with the at least one cavity being in communication with the first and second openings. A peripheral boundary of the at least one cavity is at least partially defined by a first substantially linear wall and a second opposing wall which deviates from the first substantially linear wall.  
         [0021]     In accordance with another aspect of the invention, another strain control device is provided. The strain control device includes a body having a first grasping member configured to frictionally engage a first portion of a transmission line and a second grasping member configured to frictionally engage a second portion of the transmission line. At least one cavity is defined in the body between the first grasping member and the second grasping member, wherein the at least one cavity is configured to accommodate a third portion of the transmission line therein and defines a deviation path for the third portion of the transmission line.  
         [0022]     In accordance with another aspect of the present invention, a method of controlling strain in a transmission line is provided. The method includes providing a body, forming a first opening in a first end of the body, forming a second opening in a second end of the body, and forming a cavity in a surface of the body between and in communication with the first and second openings. The cavity is defined by a peripheral boundary which includes a first substantially linear wall and a second opposing wall which deviates from the first substantially linear wall. The method further includes positioning a transmission line within the cavity such that it extends from the first opening, through the cavity and through the second opening.  
         [0023]     In accordance with another aspect of the present invention, another method of controlling strain in a transmission line is provided. The method includes providing a body having a first grasping member and a second grasping member and forming a cavity in the body in communication with the first and second grasping members, wherein the cavity is configured to provide a deviation path to the transmission line. A first portion of the transmission line is frictionally engaged with the first grasping member, a second portion of the transmission line is frictionally engaged with the second grasping member, and a third portion of the transmission line is disposed within the cavity.  
         [0024]     In accordance with another aspect of the present invention, a method of forming a strain control device is provided. The method includes providing a body, forming a first opening in a first end of the body, forming a second opening in a second end of the body, and forming at least one cavity in a surface of the body in communication with the first and second openings.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0025]     The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:  
         [0026]      1  is a cross sectional view of a prior art raceway used to house transmission lines associated with a rocket motor;  
         [0027]      FIG. 2  is a perspective view of one embodiment of a strain control device according to the present invention;  
         [0028]      FIG. 3  is a perspective view of the device shown in  FIG. 2  with its associated cover removed;  
         [0029]      FIG. 4  shows a cross section of the device shown in  FIGS. 2 and 3 ;  
         [0030]      FIG. 5  is a graphic depicting the potential deviation path of a transmission line installed in the device shown in  FIGS. 2 and 3 ;  
         [0031]      FIGS. 6A and 6B  show a cross sectional view of the device shown in  FIG. 3  with a transmission line installed therein;  
         [0032]      FIG. 7  is a graph of a potential transmission line path indicating various parameters associated with determining a maximum path deviation according to one aspect of the present invention;  
         [0033]      FIG. 8  is a perspective view of another embodiment of the present invention;  
         [0034]      FIG. 9  is a perspective view of another embodiment of the strain control device of the present invention;  
         [0035]      FIG. 10  is a perspective view of another embodiment of the strain control device of the present invention with its associated cover removed; and  
         [0036]      FIG. 11  shows an adapter which may be used in conjunction with various embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]     Referring to  FIG. 2 , a strain control device  200  is shown, which may include a body  202  and a cover  204  cooperatively mated with the body  202 . An opening  206  or a port is formed through the end  208  of the body  202 . A similar opening  210  ( FIG. 3 ) is formed through the opposite end  212  of the body  202 .  
         [0038]     Referring to  FIG. 3 , the body  202  is shown with the cover  204  removed therefrom. The body  202  may be described as including a first body section  211  and a second body section  213 . The first body section  211  includes a first cavity  214  formed in the upper surface  216  of the body  202 . The first cavity  214  is defined by a substantially linear wall  218  and an opposing curved wall  220  which laterally deviates from the substantially linear wall  218 . At one end of the first cavity  214 , the substantially linear wall  218  and the opposing curved wall  220  adjoin the opening  206 , thereby causing the first cavity  214  to be exposed through the end  208  of the body  202 .  
         [0039]     It is noted that, with the cover  204  removed from the body  202 , the opening  206  might be described as being substantially “C-shaped,” having a mouth  222  formed in the upper surface  216  of the body  202 . The opening  210  at the opposing end  212  is similarly configured. The mouths  222  of the openings  206  and  210  allow a transmission line to be inserted therethrough from the top (as shown) of body  202  for installation of the transmission line into the strain control device  200  as shall become more apparent below. While a transmission line might be longitudinally threaded through an opening or port  206  or  210  which does not include a mouth  222  (i.e., an aperture having a continual ring-like configuration), an opening configured to include a mouth  222  is desirable for assembly purposes, particularly in helping to reduce the time of installing a transmission line, as the transmission line may be effectually “snapped” into place in body  202  rather than threaded therethrough. The cover  204  ( FIG. 2 ) may then be coupled with the body  202  so as to conceal the cavities  214  and  226 , and any transmission line installed therein, from an external environment.  
         [0040]     The second body section  213  includes a second cavity  226  which is configured similarly to the first cavity  214  and includes a substantially linear wall  228  and a curved opposing wall  230 . Toward the center of the body  202 , another C-shaped opening  224  serves as a transition aperture from the first cavity  214  to the second cavity  226 . In the embodiment shown, the second cavity  226  is configured as a reversed image of the first cavity  214  with respect to a longitudinal centerline  232  that runs through the openings  206  and  210 . Thus, the two cavities  214  and  226  adjoined together at the center opening  224  define a general shape which appears somewhat sinusoidal in nature. Particularly, the two curved walls  220  and  230  serve to define a substantially sinusoidal curve opening onto the upper surface  216  of the body  202 .  
         [0041]     Referring briefly to  FIG. 4 , a longitudinal cross sectional view of the body  202 , taken parallel to the plane of the body, is shown. The various walls  218 ,  220 ,  228  and  230  can be seen to exhibit an arcuate or curved surface as they extend upwardly from the base  234  of the adjoining cavities  214  and  226 . The upwardly curved configuration of the walls  218 ,  220 ,  228  and  230  allows the walls to more naturally transition into the openings  206 ,  210  and  224 . Additionally, while the walls  218 ,  220 ,  228  and  230  might be formed to exhibit an angular transition from the base  234  of the cavities  214  and  226 , a curved transition may serve to reduce degradation of the material of the body  202  proximate the transition between the base  234  and the walls  218 ,  220 ,  228  and  230  due to repeated strain or elongation of the strain control device  200 .  
         [0042]     The cavities  214  and  226  as thus configured provide a deviation path for a transmission line installed therein. The concept of a deviation path might be better understood with reference to  FIG. 5 , which depicts a graphic  238  similar in configuration to the shape defined by the walls  218 ,  220 ,  228  and  230  of the cavities  214  and  226 . A nominal transmission line path  240  represents where a transmission line might be located upon installation of the transmission line and when no strain is induced into the strain control device  200 . The nominal transmission line path  240 , as shown, is slightly curved such that a shallow, substantially sinusoidal-type curve is formed. A linear boundary  242  and a curved boundary  244  determine the extent of allowable deviation from the nominal transmission line path  240 . Thus, when the strain control device  200 , and more particularly the body  202 , experiences an elongating or contracting strain, a transmission line installed therein may deviate from the nominal transmission line path  240  to a new path located between the two boundaries  242  and  244  without experiencing the strain exhibited by the body  202 . While the nominal transmission line path  240  is shown to be oriented substantially midway between the straight line  242  and the curved  244  boundaries, it may be placed closer to either boundary  242  or  244 , depending on the expected strains that will be seen by the strain control device  200  during operation.  
         [0043]     Referring to  FIGS. 6A and 6B , a transmission line  250  is shown as installed in the body  202 , illustrating the concept of the deviation path shown in  FIG. 5 . In  FIG. 6A , the transmission line  250  is installed in its nominal transmission line path  240  ( FIG. 5 ). As described above, the transmission line  250  may be installed by inserting the transmission line  250  through the mouth  222  ( FIG. 3 ) of the various C-shaped openings  206 ,  210  and  224 . The C-shaped openings  206 ,  210  and  224  are sized and configured to snugly grasp the transmission line  250  and hold it in place once it has been installed. In operation, the C-shaped openings might be considered constriction points, as will become more evident below.  
         [0044]     The body  202 , as shown, is attached to a structure such as, for example, a composite rocket motor casing  252 , although other structures are contemplated. The body  202  may be attached by adhesive, through the use of fasteners or through other techniques as understood by those of skill in the art.  
         [0045]     During operation of a rocket motor, the casing  252  is subject to numerous forces, including internal and external pressure environments, which induce strain in the casing  252 . The induced strain may result in elongation, contraction or other flexure of the casing  252 . The body  202  is designed to withstand strains similar to that seen in the rocket motor casing  252 . To accommodate such strain, the body  202  may be formed of an elastomeric material such as neoprene rubber, although other materials are contemplated. Additionally, forming the body of such a flexible conformable material may allow the body  202  to be installed on structures of various configurations, for example, by cooperatively mating with the radial surface of the rocket motor casing  252 .  
         [0046]     Referring to  FIG. 6B , when the rocket motor casing  252  is strained, for example, in an elongating fashion, the body  202  is formulated, configured and attached to the rocket motor casing  252  to correspondingly elongate therewith. During elongation of the body  202 , the openings  206 ,  210  and  224  substantially maintain their grasp on the transmission line  250  and cause the transmission line  250  to deviate from its nominal transmission line path  240  ( FIG. 5 ) and straighten such that it follows a path along the substantially linear walls  218  and  228 ; in other words, it approaches and/or reaches the linear boundary  242  ( FIG. 5 ) of its deviation path.  
         [0047]     A similar reaction occurs when a longitudinally contracting strain is induced into the body  202 . However, upon contraction of the body  202 , the transmission line  250  would become displaced, or deviate, from its nominal transmission line path  240  ( FIG. 5 ) toward the curved walls  220  and  230 , or toward the curved boundary  244  ( FIG. 5 ) of its deviation path.  
         [0048]     Thus, the body  202  is formulated and configured to absorb the strain induced by the structure to which it is attached (or induced by the relative movement of multiple structures between which it is attached) while substantially isolating the strain from the transmission line  250 . The body  202  may be designed such that it isolates the transmission line  250  from all of the expected strain produced by a given structure, or it may be designed such that a limited amount of strain may be ultimately transferred to the transmission line  250 .  
         [0049]     Referring now to  FIG. 7 , the design and configuration of the maximum geometric deviation path length for a curved boundary  244  exhibiting a constant radius is described. The curved boundary  244  is defined as being an arc extending through an angle of 2A (in radians), having a radius of R and an arc length of S. The corresponding linear boundary  242  may be defined to have a length 2L. The distance between the linear boundary  242  and the center  260  of the curved boundary  244  is defined as D. The equations used to determine the maximum deviation path length for such a configuration are as follows:  
                 EQ   .           ⁢   1     ⁢     :       ⁢                       A   =       cos     -   1       ⁡     (     D   R     )                       EQ   .           ⁢   2     ⁢     :       ⁢                       S   =     2   ⁢   RA   ⁢           ⁢   and                     EQ   .           ⁢   3     ⁢     :       ⁢                         Elongation   ⁡     (   strain   )       =       S   -     2   ⁢   L         2   ⁢   L                 
 
         [0050]     Thus, starting with an anticipated value of maximum elongation (either calculated or measured) and an initial length (2L) of the linear boundary  242 , one can solve for the arc length (S) of the curved boundary  244  using EQ. 3. Selecting a desired radius (R) and having solved for the arc length (S), EQ. 2 may be solved for the half angle (A) of the curved boundary  244 , which may in turn be used to solve for the distance (D) between the center  260  of the curved boundary  244  and the linear boundary  242  using EQ. 1.  
         [0051]     For example, in designing the deviation path for a first cavity  214  in the body  202  shown in  FIG. 3 , one may start with an initial strain of approximately 2.5% (or 0.025 inches per inch). With a linear boundary  242  length 2L of 12 inches and a desired radius of approximately 16 inches, the above equations can be solved to determine that the arc length S of the curved boundary  244  is approximately 12.3 inches, which traverses through an angle 2A of approximately 0.76875 radians (or approximately 44°).  
         [0052]     It is noted that while the above exemplary equations are for a deviation path having a curved boundary  244  of a constant radius, other nonlinear boundary configurations may be utilized. For example, a zigzag pattern, ellipses, parabolas, hyperbolas or any path that deviates from the linear boundary  242  may be utilized. Additionally, the cavity and the deviation path defined thereby need not include a substantially linear wall. For example, with reference to  FIG. 8 , a cavity  214 ′ may be formed having a first nonlinear wall  246  and a second opposing nonlinear wall  248  if so desired. Additionally, while most of the cavities have been defined having walls which define a generally two-dimensional deviation path, a three-dimensional deviation path may be defined within the cavity if so desired.  
         [0053]     Additionally, while certain examples have been set forth above, the strain control device  200  may be formed of various materials using various methods of construction. For example, as mentioned above, the body  202  may be formed of a neoprene rubber. However, numerous materials having various densities and mechanical properties may be used depending on the conditions of service the strain control device  200  is expected to experience. Thus, the body  202  may be formed of a low-density foam, a high-density rubber, or any of a number of materials of varying density in between. Another exemplary material may include a polyurethane which is amenable to forming dual-density molds.  
         [0054]     The body  202  may include Microballoons®, or other hollow, finely divided, hole-free, low-density particles of synthetic resins to vary the density as desired; fiber reinforcement, such as glass or carbon fibers, to tailor the mechanical properties; or the addition of various filler materials such as, for example, silica for thermal resistance. With such flexibility in composition, the strain control device  200  may be customized and tailored for various environments and conditions. For example, it may be desirable to limit the amount of strain or elongation exhibited by the body  202  during operation. Thus, the inclusion of fiber reinforcing members in the body may allow the amount of elongation exhibited by the body  202  to be limited to a predetermined amount, thereby preventing potential damage to the body  202  and/or any transmission lines disposed therein.  
         [0055]     Further, the body  202  may even be formed of a material which varies in density and/or composition from one portion of the body  202  to another, thereby allowing a very high degree of customization.  
         [0056]     The ability to form the body  202  from numerous materials also allows for flexibility in manufacturing. Desirably, the body is formed from a molding process or from an extrusion process which allows for simple and cost effective manufacturing relative to prior art systems such as was described with respect to  FIG. 1  above. Additionally, while shown as being generally flat or planar, the body  202  may be formed to a predetermined shape, such as a desired radius, for easier and more effective installation on a given structure. Alternatively, one or more surfaces may be so configured. For example, the undersurface of the body  202  may be defined as a shallow, concave curve of substantially the same radius as and exterior of a rocket motor casing  252 .  
         [0057]     Likewise, the cover  204  may be formed of various materials and through various fabrication processes. In certain applications, it may be desirable to form the body  202  and the cover  204  from different materials. For example, when using the strain control device  200  in conjunction with a rocket motor, it may be desirable to form the body  202  from a material such as silica-filled nitrile rubber (NBR), which accommodates relatively high levels of strain while also providing some thermal protection. However, it may be desirable in such circumstances to form the cover  204  from a highly thermally resistant material such as, for example, an aramid fiber, commercially known as Kevlar®.  
         [0058]     Referring now to  FIG. 9 , a strain control device  300  according to another embodiment is shown. The strain control device  300  includes a body  302  and a cover  304  cooperatively mated and interlocked with the body  302 . A first plurality of openings  306 A- 306 D or ports is formed along a first end  308  of the body  302  and a second plurality of openings  310 A- 310 D is formed through the opposing end  312  of body  302 .  
         [0059]     As seen in  FIG. 10 , which depicts the body  302  with the cover  304  removed therefrom, the first plurality of openings  306 A- 306 D open up into an associated plurality of cavities  314 A- 314 D formed in a first body section  311 . Similarly, the second plurality of openings  310 A- 310 D open to another plurality of cavities  316 A- 316 D formed in a second body section  313 . The first and second set of cavities  314 A- 314 D and  316 A- 316 D are adjoined by an additional set of openings  318 A- 318 D, respectively.  
         [0060]     The strain control device  300  is thus similar to the embodiment described above with respect to  FIGS. 2 and 3  but allows for multiple transmission lines to be installed in a single strain control device  300 . Additionally, the strain control device  300  includes a plurality of air passages  320  which both reduce the weight of the strain control device  300  and may be in communication with cavities  314 A- 314 D and  316 A- 316 D to serve as an interim air passage from the cavities  314  and  316  through the cover  304 . One or more openings  321  may be placed within the cover  304  in communication with the air passages  320 , thereby allowing air to flow from the cavities  314  and  316  without directly exposing a transmission line  250  contained therein to the external environment.  
         [0061]     Additional voids or compartments may likewise be designed into the strain control device  300  to accommodate, for example, ordnance systems (such as destruct charges  104 A—see  FIG. 1 ) associated with rocket motors as will be understood by those of skill in the art.  
         [0062]     As will be appreciated by those of ordinary skill in the art, the strain control devices disclosed herein may be arranged in various configurations as is required for specific installations and applications. For example, referring to the embodiment described with respect to  FIGS. 8 and 9 , multiple strain control devices  300  may be arranged in an end  312  to end  308  pattern such that a transmission line may be extended for a desired length along a structure. Additionally, if so desired, multiple strain control devices  300  may be layered in a laminated manner in order to accommodate a high volume of transmission lines.  
         [0063]     Additionally, the thickness of the strain control devices  300  may be varied as may be desired. The variance of thickness may be desirable in designing for specific thermal conditions or, in the case of installation on a rocket motor or other aerospace vehicle, in designing the aerodynamics of the resulting structure. Further, with reference to the destruct charge  104 A shown in  FIG. 1 , those of skill in the art will appreciate that it is necessary to maintain a minimum distance between the chevron of the shaped destruct charge and the casing of the booster rocket motor in order for the destruct charge  104 A to be effective. Thus, by providing added thickness in the body  302  of the strain control device  300 , such designs and configurations are more easily obtained.  
         [0064]     Alternative embodiments may also include a body which includes a single cavity formed therein rather than a longitudinally extending pattern of multiple cavities. Thus, for example, referring briefly to  FIG. 3 , only the first cavity  214  may exist in the body. Again, this may add to the flexibility of installing transmission lines in varied applications and configurations. Alternatively, three or more cavities may be formed in a longitudinally arranged repeating pattern. In such a case, the repeating pattern may include a reversal of cavities about a longitudinally extending centerline from one cavity to the next adjacent cavity. Such flexibility obtained from the modular nature of the strain control devices allows for multiple bodies  202 ,  302  to be arranged in varying patterns. For example, bodies of varied length may be installed in an end-to-end pattern to achieve a desired length. Further, multiple transmission lines installed in the body  302  described with respect  FIG. 10  may not all be of equal length. Thus, it may be desirable to arrange one or more bodies  202  described with respect to  FIG. 3  in an end-to-end fashion with one or more bodies  302  of  FIG. 10  so as to terminate some of the transmission lines at a given location while extending other transmission lines past the location.  
         [0065]     Referring now to  FIG. 11 , an adapter  350  is shown which may be utilized in conjunction with the various embodiments of the present invention. The adapter  350  may be described as including a generally annular body  352  having an inner radius  354  and an outer radius  356 . The adapter  350  may also include a cut portion  358  through the annular body  352  extending from the inner radius  354  to the outer radius  356 . The cut portion  358  may be a simple cut as shown, or it may include the removal of a larger portion of the annular body  352  such that the annular body  352  is substantially C-shaped with a mouth portion (i.e., like the openings  206 ,  210  and  224  described above with respect to  FIG. 3 ).  
         [0066]     The adapter  350  is designed such that the inner radius  354  is sized and configured to fit around a transmission line of a particular size. The outer radius  356  of the adapter  350  is configured to fit within one of the openings  206 ,  210  and  224  ( FIG. 3 ) of a strain control device. The adapter  350  may then function as the opening into which it is inserted but with a different internal diameter so as to frictionally or snugly grasp a transmission line of a smaller diameter positioned within a body  202 ,  302 . The adapter  350  may be sized and configured so as to effect an interference or compression fit between the adapter  350  and the opening  206 ,  210 ,  224  into which it is inserted. Thus, by using the adapter  350 , a strain control device having openings  206 ,  210 , and  224  exhibiting a particular size and configuration may accommodate transmission lines of numerous sizes and/or configurations.  
         [0067]     For example, the body  302  described with respect to  FIG. 10  may include multiple transmission lines, wherein each transmission line exhibits a different diameter. However, the use of adapters allows the openings  306 A- 306 D,  310 A- 310 D and  318 A- 318 D to be formed of a single size and configuration if so desired. Likewise, the adapters may be utilized to accommodate transmission lines having a cross section which is not substantially circular. For example, the shaped destruct charge  104 A of  FIG. 1  may be installed by using an adapter having an outer surface configured to cooperatively engage a C-shaped opening while the internal surface of the adapter  350  is configured to cooperatively engage with the shaped destruct charge.  
         [0068]     While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.