Patent Publication Number: US-2023160668-A1

Title: Body armor panel for use with personal protective vest and system for assembling same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/282,517 filed on Nov. 23, 2021, the disclosure of which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to personal protective vests, and more specifically, to a body armor panel for use with a personal protective vest. 
     BACKGROUND OF THE INVENTION 
     At least some known personal protective vests include rigid ballistic panels that are sown into the vest to provide the wearer protection from small arms fire. These rigid ballistic panels to not allow for a freedom of movement that is desired by security personal to provide additional comfort and flexibility, while providing a high level of safety protection. 
     The present invention addresses one or more of the aforementioned challenges. 
     SUMMARY OF THE INVENTION 
     In different embodiments of the present invention, a personal protective vest and a body armor panel for use with the personal protective vest are provided. 
     In one embodiment of the present invention, a body armor panel for use with a personal protective vest is provided. The body armor panel includes an outer cover defining a panel assembly cavity and a ballistic material panel assembly positioned within the panel assembly cavity. The ballistic material panel assembly includes a plurality of layered material segments defined between a strike face and a wear face. Each of the layered material segments includes a different ballistic material. The plurality of layered material segments includes a first layered material segment including a layer of a first ballistic material defining the strike face, a second layered material segment adjacent the first layered material segment and including a plurality of layers of a second ballistic material, a third layered material segment adjacent the second layered material segment and including a plurality of layers of a third ballistic material, and a fourth layered material segment adjacent the third layered material and defining the wear face. 
     In another embodiment of the present invention, a personal protective vest assembly is provided. The personal protective vest assembly includes a personal protective vest and a body armor panel positioned within the personal protective vest. The personal protective vest includes an outer surface, an inner surface, and a ballistic panel pocket defined between the outer surface and the inner surface. The inner surface includes a slot for accessing the ballistic panel pocket. The body armor panel is removably positioned within the ballistic panel pocket. The body armor panel includes an outer cover defining a panel assembly cavity and a ballistic material panel assembly positioned within the panel assembly cavity. The ballistic material panel assembly includes a plurality of layered material segments defined between a strike face and a wear face. Each of the layered material segments includes a different ballistic material. The plurality of layered material segments includes a first layered material segment including a layer of a first ballistic material defining the strike face, a second layered material segment adjacent the first layered material segment and including a plurality of layers of a second ballistic material, a third layered material segment adjacent the second layered material segment and including a plurality of layers of a third ballistic material, and a fourth layered material segment adjacent the third layered material segment and defining the wear face. 
     In a further embodiment, a method of fabricating a body armor panel is provided, The method includes forming a ballistic material panel assembly including a plurality of layered material segments defined between a strike face and a wear face, applying a first heat treatment to a ballistic material panel assembly to increase a temperature of the ballistic material panel assembly to a predefined temperature, and applying a compression treatment to the heated ballistic material panel assembly at a predefined pressure and a predefined period of time to form a hardened ballistic material panel assembly. The method also includes positioning the hardened ballistic material panel assembly within an outer cover and welding the outer cover to form a perimeter seam about a perimeter of the hardened ballistic material panel assembly to seal the hardened ballistic material panel assembly within the outer cover to form a body armor panel. The method also includes applying a second heat treatment to the body armor panel to increase a temperature of the body armor panel to a second predefined temperate and applying a conditioning treatment to the heated body armor panel to increase a flexibility of the body armor panel 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIGS.  1 - 5    are perspective views of a personal protective vest assembly including a personal protective vest and body armor panels; 
         FIGS.  6 - 9    are schematic views of a body armor panel that may be used with the personal protective vest assembly shown in  FIG.  1   ; 
         FIGS.  10  and  11    are schematic cross-sectional views of the body armor panel shown in  FIGS.  6 - 9   ; 
         FIG.  12    is a cross-sectional view of the body armor panel shown in  FIG.  10   ; 
         FIG.  13    is a partial view of a strike face of the body armor panel shown in  FIG.  10   ; and 
         FIG.  14    is a partial view of a wear face of the body armor panel shown in  FIG.  10   ; and 
         FIGS.  15  and  16    are flowcharts illustrating a method of manufacturing the body armor panel. 
         FIG.  17    is a schematic view of a system used to manufacture the body armor panel. 
         FIGS.  18 - 21    are schematic views of a brass mold and ballistic material panel assembly used to form the body armor panel. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present invention. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present invention. 
     In general, the present invention describes a personal protective vest system that includes a soft-flexible armor panel that is inserted into a personal protective vest. In some embodiments, the personal protective vest system includes the Hyperline™ soft-flexible armor panel provided by Safe Life Defense™. 
     Referring to  FIGS.  1 - 14   , in the illustrated embodiment, the present invention includes a personal protective vest assembly  10  that includes a wearable personal protective vest  12  and one or more body armor panels  14  inserted into the personal protective vest  12 . In some embodiments, the personal protective vest  12  is configured to be worn by a person covering a portion of the person&#39;s torso. In other embodiments, the personal protective vest assembly  10  may include other wearable protective articles that cover other areas of a person&#39;s body such as, for example, wearable protective articles covering the lower body, arms, legs, and head. 
     In the illustrated embodiment, the personal protective vest  12  includes a front vest panel  16  and a rear vest panel  18 . In some embodiments, the front vest panel  16  may be removable coupled to the rear vest panel  18  with a vest fastening assembly  20 . The vest fastening assembly  20  may include, for example, a Velcro assembly, a button assembly, and/or any suitable fasteners that allow the front vest panel  16  to removable attach to the rear vest panel  18 . 
     Each vest panel  16 ,  18  includes an outer surface  22  and an inner surface  24  adapted to be positioned adjacent to the person&#39;s body with the personal protective vest  12  worn by the person. A ballistic panel pocket  26  is defined between the outer surface  22  and the inner surface  24 . The ballistic panel pocket  26  is sized and shaped to receive a body armor panel  14  therein such that the body armor panel  14  is positioned within the ballistic panel pocket  26 . The inner surface  24  also including a slot  28  defined along the inner surface  24  to provide access to the ballistic panel pocket  26  to insert and/or remove body armor panel  14 . A slot fastening assembly  30  may be defined along the slot  28  to allow the ballistic panel pocket  26  to be selectively sealed. The slot fastening assembly  30  may include, for example, a Velcro assembly, a button fastener assembly, and/or any suitable fasteners that allow the slot  28  and ballistic panel pocket  26  to be sealed. 
     In the illustrated embodiment, the body armor panel  14  includes an outer cover  32  that defines a panel assembly cavity  34  and a ballistic material panel assembly  36  that is positioned within the panel assembly cavity  34 . The outer cover  32  may include a 30 denier thermoplastic polyurethane laminated nylon fabric. In some embodiments, the body armor panel  14  includes a cross-sectional shape substantially similar to the cross-sectional shape of the corresponding vest panels  16 ,  18 . In other embodiments, the body armor panel  14  may include any suitable cross-sectional shape to facilitate covering any portion of a person&#39;s body. 
     The ballistic material panel assembly  36  includes a plurality of layered material segments  38 ,  40 ,  42 ,  44  defined between a strike face  46  and a wear face  48 , with each of the layered material segments  38 ,  40 ,  42 ,  44  including a different ballistic material. When positioned within the ballistic panel pocket  26  the strike face  46  is orientated near the outer surface  22  of the corresponding vest panel  16 ,  18  and the wear face  48  is orientated near the inner surface  24  of the corresponding vest panel  16 ,  18  such that the wear face  48  is closer to a person&#39;s body than the strike face  46  with the personal protective vest  12  worn by the person. 
     In the illustrated embodiment, the plurality of layered material segments includes a first layered material segment  38  that includes a layer of a first ballistic material  50 , a second layered material segment  40  that is adjacent the first layered material segment  38  and includes a plurality of layers of a second ballistic material  52 , a third layered material segment  42  that is adjacent the second layered material segment  40  and includes a plurality of layers of a third ballistic material  54 , and a fourth layered material segment  44  that is adjacent the third layered material segment  42  and includes a plurality of layers of a fourth ballistic material  56 . The first layered material segment  38  defines the strike face  46  and the fourth layered material segment  44  defines the wear face  48 . A number of layers of the third ballistic material  54  is greater than a number of layers of the second ballistic material  52 , and a number of layers of the fourth ballistic material  56  is less than the number of layers of the third ballistic material  54 . 
     In some embodiments, as shown in  FIG.  10   , the first layered material segment  38  includes a single layer of the first ballistic material  50 , the second layered material segment  40  includes four layers of the second ballistic material  52 , the third layered material segment  42  includes eight layers of the third ballistic material  54 , and the fourth layered material segment  44  includes four layers of the fourth ballistic material  56 . In other embodiments, each segment  38 ,  40 ,  42 ,  44  may include any suitable number of layers of corresponding ballistic material. 
     The first ballistic material  50  includes an ultra-high molecular weight polyethylene fiber based composite laminate having an Areal density of about between 226 g/m 2  and 240 g/m 2  including four single layers of unidirectional sheet cross plied at 90 degrees to each other and consolidated with a rubber based matrix. In some embodiments, the first ballistic material may include DSM Dyneema® HB50 with the first layered material segment  38  includes a single layer of DSM Dyneema® HB50. 
     The second ballistic material  52  includes an ultra-high molecular weight polyethylene fiber based composite laminate having an Areal density of about between 208 g/m 2  and 224 g/m 2  including six single layers of unidirectional sheet cross plied at 90 degrees to each other and consolidated with a rubber based matrix. In some embodiments, the second ballistic material may include DSM Dyneema® SB117 with the second layered material segment  40  including four layers of DSM Dyneema® SB117. 
     The third ballistic material  54  includes para-aramid unidirectional material including four plies of para-aramid unidirectional material cross-plied in 0°/90°/0°/90° configuration. In some embodiments, the third ballistic material  54  may include Barrday Advanced Material Solutions™ U611 with the third layered material segment  42  including eight layers of Barrday Advanced Material Solutions™ U611. 
     The fourth ballistic material  56  includes a woven and laminated material having an Areal density of about 516 g/m 2 . In some embodiments, the fourth ballistic material  56  may include Barrday Advanced Material Solutions™ FCKER1017160-01129 with the fourth layered material segment  44  including four layers of Barrday Advanced Material Solutions™ FCKER1017160-01129. 
     As shown in  FIG.  11   , in some embodiments, the plurality of layered material segments includes the first layered material segment  38  including a single layer of the first ballistic material  50 , the second layered material segment  40  including six layers of the second ballistic material  52 , the third layered material segment  42  including six layers of the third ballistic material  54 , and the fourth layered material segment  44  including a plurality of layers of the third ballistic material  54  and a plurality of layers of the fourth ballistic material  56  positioned in an alternating layered arrangement such that each layer of the third ballistic material  54  is positioned between corresponding layers of the fourth ballistic material  56 . For example, the fourth layered material segment  44  may include four layers of the fourth ballistic material  56  interlaced with three layers of the third ballistic material  54  such that a top layer of fourth ballistic material  56  is adjacent a bottom layer of third ballistic material  54  of the third layered material segment  42 , and a bottom layer of fourth ballistic material  56  defines the wear face  48 . 
     In some embodiments, as shown in  FIGS.  6 - 8   , the body armor panel  14  includes a cross-sectional shape defining a lower portion  70  and an upper portion  72  extending from the lower portion  70 . The upper portion  72  has a first width  74 , and the lower portion  70  has a second width  76  that is larger than the first width  74  of the upper portion  72 . The body armor panel  14  also has a pair of opposing side walls  78 ,  80  that extend from the lower portion  70  to the upper portion  72  at opposing oblique angles. The upper portion  72  also includes an arcuate surface  82  defined along the a top edge  84  of the upper portion  72 . In other embodiments, as shown in  FIG.  9   , the body armor panel  14  may include a substantially rectangular cross-sectional shape. 
       FIG.  15    is a flowchart illustrating a method  200  of manufacturing the body armor panel  14 . The method includes a plurality of steps. Each method step may be performed independently of, or in combination with, other method steps. In the illustrated embodiment, the method  200  includes positioning the ballistic material panel assembly  36  within a dual platen heated press including placing the layered material segments  38 ,  40 ,  42 ,  44  within the dual platen heated press such that the first layered material segment  38  defines the strike face  46 , the second layered material segment  40  is between the first layered material segment  38  and the third layered material segment  42 , and the fourth layered material segment  44  is adjacent the third layered material segment  42  and defines the wear face  48 . 
     The dual platen heated press is then operated to apply a heat process to the ballistic material panel assembly  36  including applying heat at a first temperature from the strike face  46 , applying heat at a different second temperature from the wear face  48 , and applying pressure to the ballistic material panel assembly  36  during the heat process. In some embodiments, the first temperature is between about 250 and 300° Fahrenheit and the second temperature is between about 150 and 225° Fahrenheit, with the applied pressure at about 80 psi. 
     The ballistic material panel assembly  36  is then removed from the dual platen heated press after a first predefined elapsed period of time. For example, in some embodiments, the first predefined elapsed period of time is about 1.5 minutes. The ballistic material panel assembly  36  is allowed to cool for a second elapsed period of time and then cut to a desired shaped. In some embodiments, the second predefined elapsed period of time is about 30 seconds. 
     In some embodiments, the Hyperline™ soft armor panel is constructed by layering ballistic material in a 0°/0° orientation in a layered material configuration from strike face to wear face including: 1 Layer—DSM Dyneema® HB50; 4 Layers—DSM Dyneema® SB117; 8 Layers—Barrday Advanced Material Solutions™ U611; and 4 Layers—Barrday Advanced Material Solutions™ FCKER1017160-01129. The layered materials are feed into a dual platen heated press that is used to apply heat at a temperature of 250-300 degrees Fahrenheit from the strike face layer. A temperature of 150-225 degrees Fahrenheit is applied from the opposite platen to the wear face layer. Pressure is applied during the heat process at no less than 80 psi. After a minimum of 1.5 minutes the press is released and the materials is removed from the machinery and is allowed to cure for a period of no less than 30 seconds. The armor packet may be consolidated in a full sheet from which shapes may be cut by using a multi ply cutter, precision rotary blade or die cutter, or, layers may be pre-cut into uniform shapes that are layered and consolidated using the above process. 
     The ballistic material panel assembly  36  is sealed inside an outer cover  32  including water resistant TPU material such as, for example, Brookwood™ Cover HST 30d. The TPU is sealed using a High Frequency Ultrasonic Welding Machine. In some embodiments, the body armor panel  14  includes a High Frequency Weld (HFW) seal  58  about the perimeter of the ballistic material panel assembly  36  having a width of about 0.25 inches+/−0.25 inches, with a maximum gap  60  between the ballistic panel  36  and the HFW seal  58  of about 0.25 inches+−0.2 inches, with an overcut  62  having a maximum allowable width equal to 0.5 inches. A thermal label with an adhesive backing is then applied to the wear face of the sealed ballistic panel. 
       FIG.  16    is a flowchart illustrating another method  300  of manufacturing the body armor panel  14 .  FIG.  17    is a schematic view of a system  100  used to manufacture the body armor panel  14 . In the illustrated embodiment, the system  100  includes a fabric spreading and cutting machine  102 , a first industrial conveyor oven machine  104 , a hydraulic press machine  106 , a high frequency ultrasonic welding machine  108 , a second industrial conveyor oven machine  110 , and a belt press machine  112 . In method step  302 , the plurality of layered material segments are fed through the fabric spreading and cutting machine  102  and cut to predefined cross-sectional shapes to form a pre-cut, layered ballistic material panel assemblies  36 . 
     In method step  304 , a first heat treatment is applied to a pre-cut, layered ballistic material panel assembly  36  to increase a temperature of the ballistic material panel assembly to a predefined temperature. The first heat treatment may be applied to increase the temperature of the ballistic material panel assembly to the predefined temperature between about 150° and 190° Fahrenheit. For example, the pre-cut, layered ballistic material panel assembly  36  may be positioned within an industrial heat tunnel, i.e., the first industrial conveyor oven machine  104 , for a predefined period of time to increase the temperature of the ballistic material panel assembly to the predefined temperature between about 150° and 190° Fahrenheit. In some embodiments, applying the first heat treatment includes operating the industrial heat tunnel at an internal temperature between about 300° and 350° Fahrenheit, and positioning the ballistic material panel assembly within the heat tunnel for an elapsed heating time between about 1 minute and 2 minutes. For example, the first heat treatment may include feeding the pre-cut, layered ballistic material panel assembly  36  through the first industrial conveyor oven machine  104  operated with a heated environment of about 335° F. for 1 minute and 50 seconds. In some embodiments, a reflective adhesive vinyl sticker  86  is applied onto a top layer (i.e., the strike face  46 ) of the ballistic material panel assembly  36  prior to the first heat treatment. 
     In method step  306 , a compression treatment is applied to the heated ballistic material panel assembly at a predefined pressure and a predefined period of time to form a hardened ballistic material panel assembly. For example, upon completion of the first heat treatment, the heated ballistic material panel assembly is removed from the first industrial conveyor oven machine  104  and positioned onto the hydraulic press machine  106 . The hydraulic press machine  106  is then operated to apply the compression treatment including applying a pressure between about 100 to 500 tons to the heated ballistic material panel assembly. The compression treatment may include, for example, applying a pressure between about 100 to 500 tons to the heated ballistic material panel assembly for a period of 30 seconds. In some embodiments, the compression treatment may include applying 200 tons of pressure to the heated ballistic material panel assembly for a period of 30 seconds to form a hardened ballistic material panel assembly. 
     In embodiments in which the reflective adhesive vinyl sticker  86  has been applied onto the strike face  46  of the ballistic material panel assembly  36  prior to the first heat treatment, the compression treatment embeds the reflective adhesive vinyl sticker  86  into the strike face  46  such that surface of reflective adhesive vinyl sticker  86  is substantially flush with the strike face  46  of the hardened ballistic material panel assembly. 
     In method step  308 , the hardened ballistic material panel assembly  36  is positioned within the outer cover  32  and the outer cover  32  is welded to form a perimeter seam about a perimeter of the hardened ballistic material panel assembly to seal the hardened ballistic material panel assembly within the outer cover to form a body armor panel  14 . For example, as shown in  FIGS.  16 - 21   , the upon completing the compression treatment, the hardened ballistic material panel assembly  36  may be positioned between two layers of pre-cut outer cover material (e.g., Brookwood™ Cover HST 30d) having a cross-sectional shape substantially similar to the hardened ballistic material panel assembly  36 , and placed on a bottom plate  114  of the high frequency ultrasonic welding machine  108 . A brass mold assembly  116  having cross-sectional shape substantially similar to the hardened ballistic material panel assembly  36  is positioned over a top layer of the pre-cut outer cover material such that the hardened ballistic material panel assembly  36  is positioned within a cavity  118  defined through the brass mold assembly  116 . A compressible insert  120  is then placed within the cavity  118  on top of the hardened ballistic material panel assembly  36  and outer cover  32 . The compressible insert  120  includes a thickness  122  such that a top surface  124  of the compressible insert  120  is spaced a vertical distance  126  above an upper surface  128  of the brass mold assembly  116  with the compressible insert  120  contacting the outer cover  32 . As shown in  FIG.  21   , as a top plate  130  of the high frequency ultrasonic welding machine  108  is moved to contact the brass mold assembly  116 , the top plate  130  contacts the compressible insert  120  to cause the compressible insert  120  to compress and apply pressure onto the hardened ballistic material panel assembly  36  and outer cover  32  to force air trapped between the hardened ballistic material panel assembly  36  and outer cover  32  towards the perimeter of the outer cover  32  before the top plate  130  contacts the brass mold assembly  116 . Once the top plate  130  is in contact with the brass mold assembly  116 , the high frequency ultrasonic welding machine  108  is operated to weld a perimeter seam along the outer cover  32  via the brass mold assembly  116  to form a vacuum seal between the hardened ballistic material panel assembly  36  and the outer cover  32 . 
     In some embodiments, the high frequency ultrasonic welding machine  108  is operated to seal the hardened ballistic material panel assembly  36  within a water resistance thermo-plastic packaging. The water resistance thermo-plastic packaging may include a semi-transparent thermo-plastic material such that the reflective adhesive vinyl sticker  86  is visible through the water resistance thermo-plastic outer cover. In some embodiments, the compressible insert  120  includes a Nomex® material positioned within the brass mold assembly  116 . As the high frequency ultrasonic welding machine  108  operates the top plate  130  to lower and contact the brass mold assembly  116 , the top plate  130  contacts the Nomex insert to apply pressure to the top layer of water-resistance material to remove air between top/bottom layers of material and the hardened ballistic material panel assembly  36  to facilitate eliminating air from the body armor panel  14 . The high frequency ultrasonic welding machine  108  then applies high frequency radio waves to water resistance material layers through brass mold assembly to form the perimeter weld to seal the hardened ballistic material panel assembly  36  within the water resistant outer cover packaging and form an air-tight seal. The air-tight seal facilitates maintaining the shape of the assembled panel. 
     In another embodiment, the first heat treatment and the compression treatment are applied to only a portion of the plurality of the plurality of layered material segments  38 ,  40 ,  42 ,  44 . For example, in some embodiments, the first heat treatment and the compression treatment are applied only to the first and second layered material segments  38 ,  40  to form a partially hardened ballistic material panel assembly. The partially hardened ballistic material panel assembly is then layered onto the third layered material segment  42  and/or the fourth layered material segment  44  to form the completed ballistic material panel assembly, which is then placed within the outer cover  32  and into the high frequency ultrasonic welding machine  108  to weld the perimeter seam about the completed ballistic material panel as sembly. 
     In other embodiments, the first heat treatment and the compression treatment are applied only to the third layered material segment  42  and/or the fourth layered material segment  44  to form the partially hardened ballistic material panel assembly. The first and second layered material segments  38 ,  40  are then layered on top of the partially hardened ballistic material panel assembly to form the completed ballistic material panel assembly prior to welding the outer cover  32  onto the completed ballistic material panel assembly. 
     In method step  310 , a second heat treatment is applied to the body armor panel  14  to increase a temperature of the body armor panel  14  to a second predefined temperate. For example, after the hardened ballistic material panel assembly  36  has been welded within the outer cover  32  to form the sealed body armor panel  14 , the sealed body armor panel  14  is then placed into the second industrial conveyor oven machine  110  for a predefined period of time to increase the temperature of the sealed body armor panel  14  to facilitate increasing a flexibility of the sealed body armor panel  14 . The second industrial conveyor oven machine  110  is operated at a lower internal temperature then the first industrial conveyor oven machine  104 . 
     In method step  312 , a conditioning treatment is then applied to the heated body armor panel  14  to increase a flexibility of a conditioned body armor panel  14 . For example, after the second heat treatment is completed, the heated body armor panel  14  is fed through a belt press machine  112  that includes a pair of opposing conveyor belt systems that form roller pairs of varying heights. As the heated body armor panel  14  is moved through the roller pairs the heated body armor panel  14  is moved through various vertical positions, thereby breaking-in the heated body armor panel  14  to increase the flexibility of the finished, conditioned body armor panel  14 . 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims. 
     Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing or other embodiment may be referenced and/or claimed in combination with any feature of any other drawing or embodiment. 
     This written description uses examples to describe embodiments of the disclosure and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.