Abstract:
An artificial nipple is formed of an elastomeric polymer by use of 3D printing after imaging of a mother&#39;s breast in an active state of lactation. The artificial nipple used as an attachment to a baby bottle or as the nipple component of a pacifier. Use of an artificial nipple formed in this manner mitigates a problem with nipple confusion, as may otherwise manifest in newborn offspring.

Description:
Related Applications 
       [0001]    This application s claims benefit of priority to U.S. provisional patent Application Nos. 62/330,367 and 62/330,634 filed May 2, 2016, each of which are incorporated by reference as though fully replicated herein. 
     
    
     BACKGROUND 
       [0002]    Field of the Invention 
         [0003]    The present disclosure pertains to the field of three dimensional printing (3D printing) of anatomy. More particularly, 3D printing is used to replicate a nursing mother&#39;s nipple. 
         [0004]    Description of the Related Art 
         [0005]    Breastfeeding is associated with many advantages for both mother and baby. Some studies suggest an association between breastfeeding and; (1) lower risk of asthma or allergies; (2) fewer ear infections, respiratory illnesses and bouts of diarrhea; (3) higher IQ scores for the baby later in childhood; and (4) improved weight for both mother and baby. Many breastfed infants are also fed using conventional baby bottles. Nipple confusion sometimes arises where a bottle-fed baby “forgets” how to nurse on mother&#39;s nipple. This happens because breastfeeding requires far more vigorous mouth and tongue motions and greater muscle coordination than does bottle-feeding. Thus, a newborn who is exposed to conventional bottle nipples or even conventional pacifiers can cease to nurse properly. The art provides no known solution to this problem, other than to let the baby rediscover how to nurse. 
         [0006]    3D printing, which is sometimes called additive manufacturing, is a well-known process for producing three dimensional objects. Conventionally, robotic processing utilizes inkjet-like printer heads to deposit successive layers of material into the shape of a three dimensional article. Deposition methods, among others, include such extrusion technologies as fused deposition modeling and, fused filament fabrication of thermoplastics. See, for example, Chee Kai Chua; Kah Fai Leong; Chu Sing Lim (2003). Rapid Prototyping. World Scientific. p. 124. ISBN 978-981-238-117-0. Powder bed deposition technologies include selective heat sintering and selective laser of thermoplastic powder. Powder bed and inkjet head printing may be used to deposit most metal alloys, plaster and powdered polymers. See for example, U.S. Pat. No. 4,247,508 to Housholder for “Molding Process” issued to Hiemenz; and “Rapid prototypes move to metal components, EE Times, Mar. 9, 2007. 3D printing processes may be utilized to make 3D articles utilizing polymers, metals, and ceramics. By way of example, U.S. Pat. No. 7,569,273 issued to Bredt et al., describes the use of powder deposition technology to deposit thermoplastic silicone materials. 
         [0007]    3D articles may be printed utilizing a computer-aided design package, a scanner, an ordinary camera, or a 3D specific camera to feed data to photogrammetry software. Commercially available software for this purpose includes, for example, ContextCapture, Pix4Dmapper, Photoscan,  12 3D Catch, Bundler toolkit, PIXDIM, and Photosketch. 3D Printing has been utilized to make human prosthetic devices. For example, U.S. Pat. No. 5,370,692 to Fink et al. describes the rapid manufacture of bone prosthesis by use of medical computer aided imaging to make a replica of original bone that is deposited using laser-bonded layers of ceramic particles. U.S. Pat. No. 8,454,362 describes the use of a 3D camera to capture data that may be used in making a dental prosthesis, such as a crown. 
         [0008]    U.S. Pat. No. 9,044,380 to Sabree et al. describes a process of impression-molding a mother&#39;s breast to make a mold from which may be cast either a nipple for a baby bottle or a pacifier. This is problematic in the sense that, practically speaking, the time required for the impression-forming process precludes making a mold of the breast in an active state of lactation, as described below. Moreover, the resins utilized in casting custom nipples from this impression are of questionable safety when used in combination with baby products. Lastly, the impression-forming process physically distorts the nipple area of the breast, which defeats the purpose of forming a custom nipple that closely resembles that of a mother&#39;s breast. 
         [0009]    Some attempts have been made to make artificial nipples by use of 3D printing, but without good success. WO2017/019401 to Dretzaka-Kaye et al describes a vacuum chamber that retains a breast in position for a laser scanning operation that creates a digital imaging file. The nipple region of the breast may be reproduced as an artificial nipple by use of 3D printing, stereo lithography or molding processes. Here the vacuum problematically distorts the mother&#39;s nipple to a non-natural state other than that which would be presented to an infant. Similarly, WO2016/154681 to Mobbs shows imaging of a breast that may be reproduced by use of 3D printing; however, the breast is not placed in an active state of lactation as would normally presented to an infant. 
       SUMMARY 
       [0010]    The presently disclosed instrumentalities advance the art and overcome the problems outlined above by mitigating the problem of nipple confusion. This is done by the use of 3D printing technology to provide an artificial nipple or pacifier that closely resembles the naturally occurring nipple of a child&#39;s mother or wet nurse in a state of active lactation. As used herein a “child” may be a human child or a non-human mammalian child. 
         [0011]    In one aspect, an elastomeric artificial nipple structure is formed for use as a substitute nipple or pacifier for a nursing child. The artificial nipple structure is custom-made to provide a nipple portion that closely resembles an actual nipple in an active state of lactation that is normally presented to the child when nursing. Generally speaking, the nipple portion described above reproduces the areola and nipple region of a breast and may also transition into an area of the breast posterior of the areola. The actual nipple may be, for example a human nipple. As used herein, the term “closely resembles” means that the reproduced region of areola and/or nipple of a mother&#39;s breast is exactly reproduced within a dimensional tolerance that externally deviates less than about 4 or 5% from the original in terms of external length, height and width, or another suitable tolerance that is achievable by 3D printing processes. This variance is preferably less than 3% and more preferably less than 1%. The reproduced region of areola and nipple may be provided with surface texturing features corresponding to those of the actual breast, or else artificial texturing may be provided within the range of dimensional tolerance as an aid to simulate such texture and facilitate suckling. 
         [0012]    In another aspect, the artificial nipple may be formed as a component of a baby bottle or a pacifier. 
         [0013]    In one aspect, the artificial nipple structure may be cast from a mold to which a synthetic resin may be added to form elastomeric artificial nipples. 
         [0014]    A process for making the elastomeric artificial nipple includes converting a breast into an active state of lactation and imaging the breast to obtain 3D image data including a nipple component of the breast. The 3D image data is then processed to provide a print data file, which is submitted to a 3D printer for printing of the artificial nipple structure based upon the print data file to provide an artificial nipple structure with a component that closely resembles a nipple region of the breast. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows a human breast in a resting state; 
           [0016]      FIG. 2  shows the breast of  FIG. 1  inserted into a breast pump, which converts the breast from the resting state to an active estate of lactation; 
           [0017]      FIG. 3  show the breast as it is being imaged in the active state with consequent processing of the image data to provide print data that is suitable for purposes of 3D printing; 
           [0018]      FIG. 4  shows a 3D printer in a state of printing an artificial nipple structure based upon the print data; 
           [0019]      FIG. 5  provides additional detail with respect to forming the artificial nipple structure according to one embodiment; 
           [0020]      FIG. 6  shows an artificial nipple structure in the form of a nipple for a baby bottle; 
           [0021]      FIG. 7  shows an artificial nipple structure in the form of a pacifier according to one embodiment; 
           [0022]      FIG. 8  shows an artificial nipple structure in the form of a pacifier according to one embodiment; 
           [0023]      FIG. 9  shows a mold that is used for casting of an artificial nipple structure; 
           [0024]      FIG. 10  is a process diagram for making the artificial nipple structure according to; one embodiment; 
           [0025]      FIG. 11  is a process diagram for making the artificial nipple structure according to; one embodiment; 
           [0026]      FIG. 12  is a process diagram for making the artificial nipple structure according to; one embodiment; 
           [0027]      FIG. 13  shows an active state breast as it is being cast to form an impression; 
           [0028]      FIG. 14  shows a casting aid including a nipple portion that is recast in positive form from the impression  FIG. 13 ; 
           [0029]      FIG. 15  shows a mold that is made utilizing the casting aid of  FIG. 14 ; and 
           [0030]      FIG. 16  is a process diagram showing the steps of making a mold, such as the mold shown in  FIG. 15 . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    The female breast is ordinarily divided into 15-25 lobes that are separated by connective and adipose tissue. These lobes radiate out from the nipple and are subdivided into lobules. Each lobe drains into a lactiferous duct and each duct has a dilation called a lactiferous sinus behind the nipple for milk storage. As is well known, the ducts branch and grow when activated by estrogen and progesterone stimulation during pregnancy. These stimulated glandular units form alveoli which are secretory units lined by simple cuboidal epithelium, surrounded by a basement membrane and wrapped in myoepithelial cells which surround the entire alveolus. The developing alveoli replace much of the adipose tissue. 
         [0032]      FIG. 1  shows one-such human breast in a resting state  100 . The breast in state  100  is capable of producing milk for expression to an infant almost immediately upon demand, but in the resting state  100  has not has not yet let down the milk for immediate delivery to a child. The breast  100  has areola  102  from which nipple  104  protrudes in a substantially cylindrical shape. No milk is produced during the non-pregnant and non-lactating state. The internal breast (not shown) consists of mostly adipose tissue with small amounts of glandular tissue and ducts. 
         [0033]      FIG. 2  shows the breast positioned within an intake  200  of a breast-pump  202  The breast pump  202  provides a physical stimulus converting breast  100  from the resting state shown in  FIG. 1  to an active state  100 A in which the breast is ready to express milk. Other means may perform this state conversion equally as well, such as by actual nursing activity or manual stimulation. The breast pump  202  may be any type of commercially available breast pump that is commonly used by nursing mothers to harvest breast milk for later consumption by a nursing child, such as an infant. 
         [0034]      FIG. 3  shows the breast in a naturally occurring active state  100 A, which is associated with the well-known morphological changes indicated as areola  102 A and nipple  104 A. These changes are ascertainable by way of comparison between  FIG. 1  and  FIG. 3  where  FIG. 1  shows the breast in a resting state  100  and  FIG. 3  shows the same breast in a naturally occurring state  100 A of active lactation. As shown in this comparison, the areola  102 A and nipple  104 A form a relatively conical structure, compared to areola  102  and nipple  104 . This change is due to the accumulation of milk in interior ducts (not shown) proximate areola  102 A as is well known in the art. When lactation ceases or sucking ceases from the breast in the active state  100 A, these changes may revert to the resting state  100  within about 2 minutes. Breasts come in all shapes and sizes, as do areolae and nipples, so the change comparison described herein is provided by way of example to illustrate that morphological changes do occur between resting and active states, but it is understood in the art that the usual changes described here are not universally applicable to all breasts. 
         [0035]    As shown in  FIG. 3 , a conventional 3D camera  300  may be used to photograph breast  100 A in the naturally occurring active state. Additional cameras may be provided for stereoscopic vision, especially in the area  310  proximate areola  102 A and nipple  104 A. The cameras  300 ,  302 ,  304  provide image data to an imaging computer  306 , which utilizes commercially available software to create an imaging file, here represented as data  308 , of a type commonly utilized to operate a 3D printer in making an article. The imaging focuses especially on the area  310  proximate areola  102 A and nipple  104 A to provide sufficient structure for an infant to nurse. A fiducial  312  may be drawn onto breast  100  or placed as an adhesive sticker in the area  310  to provide a more precise indicator of scale that may be processed to render a true-to-scale representation of region  310  in the data  308  processed by computer  306 . This processing preferably reproduces the structure of region  310  atop a standardized base section that is suitable for use as a nipple for a baby bottle or pacifier, as explained in more detail below. 
         [0036]    For embodiments utilizing only one camera, a preferred aspect is to use a 3D scanning technology, such as Microsoft&#39;s MobileFusion™ application, which turns an iPhone® into a 3D scanner. This is a class of device that obtains a plurality of pictures from a single imager and is able to use depth of scale in rendering a 3D image that is readily convertible into print image data  308  for use in 3D printing applications. 
         [0037]    As shown in  FIG. 4 , the computer  306  data  308  to a commercially available 3D printer  400  where a print head  402  forms an artificial nipple structure  404 . The printer  400  is selected from among commercially available options for its ability to print a 3D image as described above. The material that is printed depends upon the desired manner of constructing a 3D nipple structure that closely resembles that of region  310  which is imaged according to the discussion of  FIG. 3 . The artificial nipple structure may be suitable for use as a nipple for a baby bottle or pacifier. It will be appreciated that the use of 3D printing may be associated with structural artifacts, such as the formation of fine lines in the reproduced structure that are present in the artificial nipple structure that are not found in the actual nipple  100 A. Nonetheless, generally speaking, the technology of 3D printing has sufficiently advanced that such lines are suitably small that they do not preclude making an artificial, nipple structure which closely resembles the actual nipple  100 A. 
         [0038]    By way of example,  FIG. 5  shows the artificial nipple structure  404  as it is being formed in successive layers by the print head  402 . Here the artificial nipple structure  404  is a nipple for use in a baby bottle as is also shown in  FIG. 6 . The artificial nipple structure  404  includes a base section  500  that is dimensionally compatible with a conventional baby bottle  600  (see also  FIG. 6 ). The conventional portion of the design includes, for example, a screw-on cap  602  (see  FIG. 6 ) that compresses an elastomeric flange  502  against a milk reservoir body  604  to form a seal at edges  504 ,  506 . A bulge  508  passes through orifice  606  of the screw-on cap  602  to present an artificial nipple structure  404  including portion  510  that closely resembles or reproduces, from an exterior perspective, the features of active breast region  310  as shown in  FIG. 3 . As shown in  FIG. 5 , portion  510  has not yet been completely printed, but the object of this printing exercise is to custom-form the artificial nipple structure of portion  510  in a manner reproduces as closely as possible the nipple structure in region  310  of a mother or wet-nurse. Thus, the artificial nipple structure  404 , as provided with as internal flow passageway  512 , may be used to dispense milk or formula to an infant. The internal dimensions of artificial nipple structure  404  may be reduced by a form factor, such as by 75% to 95% of the external dimensions to provide an overall wall thickness that is suitably strong for purposes of nursing a child without substantial risk of creating a choking hazard. It will be appreciated that the base section  500  may be 3D printed in its entire form atop a digitally created base section  500  or, alternatively, provided as a preexisting blank in the form shown generally in base section  500  to which area  510  is successively added by use pf the printer head  402 . 
         [0039]    The artificial nipple structure  404  is alternatively a pacifier  700  closely resembling the actual nipple structure of a mother or wet-nurse. This is shown, for example, in  FIG. 7  where a pacifier  700  has been 3D printed to reproduce the active state nipple structure  310  (see  FIG. 3 ) of a mother or wet nurse. The resulting nipple  702  closely reproduces the active state nipple structure  310  of a mother or wet nurse, and this has been by imaging an active state breast  100 A according to the process described above. The pacifier  700  may be printed as a one-piece article of manufacture on a base section  704  including a plate  706  with indentations  708 ,  710  to accommodate a baby&#39;s nose when the baby is sucking on nipple  702 , together with a cylindrical base  712  connected to grip ring  714 . The nipple  702  may be solid or it may optionally have a hollow interior  716 , the positon of which is indicated by dashed interior lines  718 ,  720 , to promote flexion as a baby sucks on nipple  702 . 
         [0040]    The grip ring  714  may be integrally formed with the cylindrical base  712  in a single printing operation. Alternatively, the grip ring  712  may be formed with barbs, such as barb  722  at opposed ends, the barbs being insertable through an orifice  724  in the cylindrical base  712  communicating with the hollow interior  716  such that the barb  722  expands in the interior  716  to preclude removal of the barb from the orifice. 
         [0041]      FIG. 8  shows the artificial nipple structure as another type of pacifier  800  in which the same type of nipple  702  as is shown in  FIG. 7  is 3D printed atop a different base  802 . The base  802  has a cylindrical section  804  that is integrally bonded to the nipple  702 . The cylindrical section  804  has an opening  806  leading to a hollow interior space, the position of which is indicated by dashed lines  718 ,  720 . This opening  806  is sufficiently large to accommodate a finger such that the nipple  702  may be positioned on a finger and placed in an infant&#39;s mouth to stimulate sucking activity. A grip tab  808  is provided to facilitate positioning and/or removal of the pacifier  600  from the infant&#39;s mouth. 
         [0042]      FIG. 9  shows a mold  900  including a first part  902  and a second part  904 . The first part  902  and the second part  904  are separably adjoined along junction  906 . The first part  902  has a recess defined by internal margins  908  formed therein. The margins  908  may be determined by imaging of an active state breast  100  as represented above in  FIG. 3  and the discussion thereof; however, the margins  908  reproduce that image as a negative or subtractive structure formed in the matrix of the first part  902 . Thus, the first part  902  may be 3D printed to reproduce the breast  100  as a negative image or hole defined by margins  908 . 
         [0043]    An internal structure  910  is formed integral to the second part  904 , fitting within the recess formed by margins  908 . The internal structure  910  has complementary dimensions with respect to the margins  908 , such that a space  912  is provided therebetween. As shown in  FIG. 9 , the space provides an artificial nipple structure  404  according to the embodiment of  FIG. 5 . In one aspect, the space  912  may be provided by 3D imaging as described above to impart complementary dimensions to the nipple structure  910  making the internal structure  910  is smaller than the margins  908  by a form factor, such as a reduction to 75% to 95% of the outer dimensions defined by margins  908 . The space  912  may be thickened as needed, especially in areas where sucking action occurs to mitigate the risk where breakage of the end product may cause a choking hazard. A connector  914  provides a pathway communicating a source of injection molding polymer  916  with the space  912 . Thus, a polymer  916  in liquid form may be introduced into the space  912  where it is allowed to harden as it cures. 
         [0044]    The liquid polymer  916  is formulated to cure, for example, into a PVC plastic, latex or silicone based material, and is preferably silicone or a copolymer of silicone in a variety that has regulatory approval for use in the nipples of baby bottles or pacifiers as the case may be. The material may be, for example, a medical grade silicone. The material is preferably free of bisphenol-A (BPA) and nitrosamines. 
         [0045]    As shown in  FIG. 9 , the numeral space  912  is constructed and arranged to provide the artificial nipple structure as a nipple for use in a baby bottle, corresponding to  FIG. 5 . It will be appreciated that the space  912  may also be constructed and arranged to provide the artificial nipple structure  404  in the form of pacifiers  700 ,  800  as shown in  FIGS. 7 and 8 . 
         [0046]      FIG. 10  shows a process  1000  of making the artificial nipple structure  500 . To begin, a resting state breast is converted  1002  to active state, as described supra in context of  FIGS. 1-3 . The active state breast is imaged  1004  in a 3D context, as described in  FIG. 3 . The image data is processed  1006  to provide data, such as a STL file, that is compatible with software for use in 3D Printing. Step  1008  is optionally performed as needed to resolve imaging errors, as provided for in some commercially available software packages. This may require operator intervention to resolve apparent data errors that are visually apparent on a model image after the processing of step  1006 . An artificial nipple structure, such as is shown as the artificial nipple structure  404  in any one of  FIG. 5, 7 or 8 , is then printed  1010  as described in context of  FIG. 4 . The artificial nipple structure is optionally but preferably inspected and finished  1012  in a manual operation, after which the artificial nipple structure may be presented to a child in the intended environment of use. The steps  1010 - 1012  may be successively repeated to provide a plurality of elastomeric nipple structures cast from a single mold or 3D image. 
         [0047]      FIG. 11  shows process  1100 , which is a variant of process  1000  intended for molding of an artificial nipple structure  404 . In  FIG. 11 , identical numbering is preserved for steps that are the same as the correspondingly numbered steps shown in  FIG. 10 . Step  1102  entails making a negative image data file such that the data may be utilized s a subtractive image to print  1104  the first part  902  and the second part  904  of mold  900 , as shown in  FIG. 9 . With the mold complete, a suitable resin is applied  1106  to the mold, such as by injection molding or pouring resin into the mold, to form the artificial nipple structure. The resin is allowed to cure  1108  before the artificial nipple structure is removed  1110  from the mold. The steps  1106 - 1012  may be successively repeated to provide a plurality of elastomeric nipple structures cast from a single mold. 
         [0048]      FIG. 12  shows process  1200 , which is a variant of process  1000  intended for molding of an artificial nipple structure  404 . In  FIG. 12 , identical numbering is preserved for steps that are the same as steps shown in  FIG. 10 . Step  1202  printing an artificial nipple structure as a casting aid; however, this process step differs from that of step  1010  because any material may be used in the printing operation. Hard plastic is preferred. The casting aid is then cast to make a mold  900  including the first part  902  and the second part  904  of mold  900 , as shown in  FIG. 9 . The mold  900  may be made of any curable polymeric resin, which is cured  1206  to complete the mold  900 . With the mold complete, another resin is applied  1208  to the mold, such as by injection molding or pouring resin into the mold, to form the artificial nipple structure. The resin is allowed to cure  1210  before the artificial nipple structure is removed  1212  from the mold. The steps  1208 - 1012  may be successively repeated to provide a plurality of elastomeric nipple structures cast from a single mold. 
         [0049]      FIG. 13  shows an alternative way of making an artificial nipple structure that does not involve the use of 3D printing. Imaging of the active state breast  100 A is not required when the active state breast  100 A is placed in a molding device  1300 . The molding device  1300  may be shaped generally like a funnel with a bowl  1302  for receipt of the active state breast  100 A. The bowl  1302  orients the nipple region  1304  of the active state breast  100 A generally central to cylinder  1306 . One or more through orifices  1308  communicate thorough the cylinder  1306  for receipt of a fast curing resin  1310 . One example of a suitable quick setting resin is a dental impression resin, such as the siloxane and silicone based material as represented by Alginot FS™ sold by Kerr Corporation of Orange, Calif. The resin within cylinder  1306  cures to leave an impression of the nipple region  1304  in plug  1312 . A plunger  1314  may be reciprocated  1316  within the cylinder  1306  to dislodge the plug  1312  and subsequently repositioned for a new molding process. The internal surfaces of cylinder  1306  may be coated with a release agent to facilitate removal of the plug  1312 . 
         [0050]    As shown in  FIG. 14 , the portion of the plug  1312  in which is formed the impression of nipple portion  1304  may be cast from the cured resin as a positive reproduction  1304 A, trimmed and manually fitted atop a base section, such as the base section  500  of  FIG. 5 , to form casting aid  1400  Alternative base sections include the base sections  704  and  802  for use as pacifiers as shown in  FIGS. 7 and 8 . The casting aid  1400  is then used in a casting process to make a top portion  1500  of mold  1502 , as shown in  FIG. 15 . The top portion  1500  includes indentation  1504 , which defines space  1506 . A second portion  1508  of mold  1502  separably adjoins the first portion  1500  at junction  1510  and includes a stepped protrusion  1512 . Introduction of resin  1514  through connector orifice  1516  fills space  1506  with resin that mat be allowed to cure in forming any one of the artificial nipple structures  404  described above. However, these artificial nipple structures will not have the process artifacts associated with 3D printing. 
         [0051]      FIG. 16  shows a process  1600  of making an artificial nipple structure as illustrated in  FIGS. 13-15 . A breast is placed  1602  in an active state of lactation, then cast  1604  using quick-setting resin to form an indentation that reproduces at least the nipple region of the breast in the active state. The indentation is recast  1606  to form a positive reproduction of the nipple region. The nipple portion resulting from step  1606  is fitted  1608  to a base section that is essentially an adaptor for presenting the nipple portion in the intended environment of use. This base section may be, for example, any one of base sections  500 ,  704  or  802  described above. The fitting operation may be performed manually, as by adhering the nipple portion to the base to form a casting aid. Alternatively, the fitting operation may be done digitally to meld data connecting the nipple portion to the base, with subsequent  3 d printing of the casting aid. In either case, a casting aid results from the competed fitting operation. The casting aid is then used to form  1610  a mold component that embodies an impression of the casting aid. This casting step  1610  may be successively repeated to provide a plurality of elastomeric nipple structures cast from a single mold. The resulting mold is utilized to cast  1612  an artificial nipple structure. After optional inspection and finishing  1614  the artificial nipple structure is presented  1616  to a child. The steps  1612 - 1614  may be successively repeated to provide a plurality of elastomeric nipple structures cast from a single mold. 
         [0052]    Although a human nipple is depicted in the drawings, it will be appreciated that the instrumentalities described herein are not limited to human nipples and may be extended to other mammalian nipples, such as those of other primates, livestock, or mammals constituting endangered species. 
         [0053]    Those of ordinary skill in the art will understand that the foregoing discussion teaches by way of example and not be limitation. Accordingly, what is shown and described may be subjected to insubstantial change without departing from the scope and spirit of invention. The inventors hereby state their intention to rely upon the Doctrine of Equivalents, if needed, in protecting their full rights in the invention.