Abstract:
A protective cover for a portable computing device includes a first hardshell component, a second hardshell component, and a hinging element. The first hardshell component removably snaps onto a first portion of the portable computing device to protect the first portion of the portable computing device. The second hardshell component removably snaps onto a second portion of the portable computing device to protect the second portion of the portable computing device. The hinging element comprises a flexible material and is attached to the first hardshell component and the second hardshell component such that the hinging element of the protective cover aligns with the hinging structure of the portable computing device. The hinging element flexes to allow the second portion of the portable computing device to remain articulable relative to the first portion of the portable computing device when the protective cover is installed on the portable computing device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/050,791, filed on Mar. 17, 2011, which claims priority to U.S. Provisional Patent Application 61/317,537, filed on Mar. 25, 2010, and to U.S. Provisional Patent Application 61/314,954, filed on Mar. 17, 2010, all of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     Protective covers for handheld electronic devices, such as various types of MP3 players, video players, cell phones, smart phones, satellite phones, walkie talkies, GPS navigational devices, telematics devices, pagers, monitors, personal data assistants, bar code scanners, as well as various types of computers, including portable computers, laptop computers, handheld computers, ultra-mobile computers, tablet computers, and various hybrid devices that combine two or more of these functions, provide a valuable function in preventing damage to these handheld electronic devices. Various types of protective cases are available that provide a varying amount of protection. 
     SUMMARY 
     A protective cover for a portable computing device includes a first hardshell component, a second hardshell component, and a hinging element. The portable computing device has at least a first portion and a second portion where the second portion is connected to the first portion through a hinging structure such that the second portion articulates relative to the first portion. The first hardshell component of the protective cover removably snaps onto the first portion of the portable computing device to protect at least one surface of the first portion of the portable computing device. The second hardshell component removably snaps onto the second portion of the portable computing device to protect at least one surface of the second portion of the portable computing device. The hinging element comprises a flexible material and is attached to the first hardshell component and the second hardshell component such that the hinging element of the protective cover aligns with the hinging structure of the portable computing device. The hinging element of the protective cover flexes to allow the second portion of the portable computing device to remain articulable relative to the first portion of the portable computing device when the protective cover is installed on the portable computing device. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of an embodiment of a protective case and a sliding/articulating handheld electronic device. 
         FIG. 2  is a perspective view of a hard plastic back shell of the embodiment of  FIG. 1 . 
         FIG. 3  is a perspective view of an assembled silicone layer and hard plastic back shell. 
         FIG. 4  is another perspective view of the assembled hard plastic back shell and silicone layer of the embodiment of  FIG. 1 , and the sliding/articulating handheld electronic device. 
         FIG. 5  is a perspective view of the hard plastic front shell of the embodiment of  FIG. 1 . 
         FIG. 6  is a perspective view of an embodiment of an articulating handheld electronic device. 
         FIG. 7  is a perspective view of an embodiment of a sliding handheld electronic device. 
         FIG. 8  is an exploded view of another embodiment of a protective case for a sliding/articulating handheld device. 
         FIG. 9  is a schematic isometric view of an embodiment of a protective case that includes an integrated silicone hinge. 
         FIG. 10  is a schematic isometric view of an embodiment of a handheld electronic device. 
         FIG. 11  is a front view of the embodiment of  FIG. 9 . 
         FIG. 12  is a back view of the embodiment of  FIG. 9 . 
         FIG. 13  is an exploded view of the three pieces of the embodiment of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     Many electronic devices are constructed with two pieces that may be joined by hinges or various sliding mechanisms. Examples of such devices may be hand held mobile telephones, portable gaming devices, laptop computer, netbook computers, or other devices. 
     A protective cover or outer shell for these devices may be constructed with two hard shell components, one for the front portion of the electronic device and one for the rear portion. A silicone or other flexible component may be held by one or both of the hard shell components. 
     In some embodiments, the flexible component may be held by only one of the hard shell components. In an example of such an embodiment, the flexible component may be installed underneath the rear hard shell component. 
     In some embodiments, the flexible component may be held or retained by both hard shell components. In an example of such an embodiment, the flexible component may be retained by both hard shell components and the flexible component may have a portion that covers a hinge or other mechanism that may join the two portions of the electronic device. 
     The flexible component may have pads or other mechanisms that may allow a user to active a button on the electronic device when the cover is installed. Some embodiments may have removable covers for earphone ports or other electrical connectors as well. 
     In some embodiments, the protective cover may be a removable cover that may be installed and removed by a consumer. In such embodiments, the protective cover may have logos, colors, or other designs that allow a user to personalize their electronic device. In such embodiments, the protective cover may have snaps or other engagement mechanisms that may be easily installed and removed by a consumer. 
     In other embodiments, the protective cover may not be a consumer installed cover. In such embodiments, the protective cover may be installed by the manufacturer of the electronic device and may be an integral part of the electronic device. In such embodiments, the protective cover may be installed using fasteners, adhesives, snaps, or other mechanisms for which a typical consumer may not have access or ability to install or remove. 
       FIG. 1  is a perspective view of a protective case  100  and a sliding/articulating handheld electronic device  104 . Many handheld electronic devices have a back portion  110  and a front sliding/articulating front portion  112 . Mobile phones, for example, may have a sliding front portion that may include a screen that slides to an open position to access a keyboard. Other mobile phones may have a front portion, such as sliding/articulating front portion  112 , that articulates on hinges to expose a keyboard. 
     In order to provide a cover for both the back portion  110  and the sliding/articulating front portion  112 , separate hard plastic shells, such as hard plastic front shell  102  and hard plastic back shell  108 , can be utilized. However, plastic shells that attach directly to front and back portions of handheld electronic devices often do not provide a large amount of protection, especially against shocks from impacts. In addition, hard plastic shells may provide openings to operational features of the handheld electronic device that further reduces the protection provided by hard plastic shells. 
     As illustrated in  FIG. 1 , the hard plastic front shell  102  has a series of hooks, such as front shell hooks  146 ,  148 ,  150 , and other front shell hooks (not shown), on opposing sides of the hard plastic front shell  102 , that attach the hard plastic front shell  102  to the sliding/articulating front portion  112  of the sliding/articulating handheld electronic device  104 . 
     The hard plastic front shell  102  may be constructed from thermoplastic polymers and has a hardness generally in the range of 65 to 120 on the Rockwell scale for HDPE, acrylic, PP, PVC, ABS, nylon, 10% GF PC. A narrower range of 105-115 on the Rockwell scale can be used for ABS and PC. These ranges are exemplary only and may vary with specific materials. The thermoplastic polymers can be molded, die cast or otherwise formed to a desired shape. Other materials can also be used for the hard shell, including metals that can be formed or machined to a desired shape. 
     The hard plastic front shell  102  may attach directly to the sliding/articulating front portion  112  of the sliding/articulating handheld electronic device  104 . The hard plastic front shell may allow the sliding/articulating front portion  112  to slide or articulate between an open and closed position without interfering with the sliding/articulating motion provided by a sliding/articulating connector (not shown). The hard plastic front shell  102  may provide impact protection and may have an elevated surface that may protect the sliding/articulating front portion of the sliding/articulating handheld electronic device  104  from impacts. 
     As also illustrated in  FIG. 1 , a hard plastic back shell  108  has a plurality of back shell hooks  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 ,  128  that attach the hard plastic back shell  108  to the back portion  110  of the sliding/articulating handheld electronic device  104 . Again, the manner in which the back shell hooks  114 - 128  attach to the back portion  110  of the sliding/articulating handheld electronic device  104  may not impede the operation of the sliding/articulating front portion  112  of the sliding/articulating handheld electronic device  104 . 
     The hard plastic back shell  108  also has a plurality of back shell openings  152 ,  154 ,  156 ,  158 ,  160  that are aligned with electronic device operational features  174 , including buttons and ports, in the sliding/articulating handheld electronic device  104 . The electronic device operational features  174  include the operational features illustrated in  FIG. 1 , as well as the device buttons  186 ,  188 , illustrated in  FIG. 4 , and other operational features that may exist on the sliding/articulating handheld electronic device  104 . The hard plastic back shell  108  can be made from the same materials as the hard plastic front shell  102  with the same range of hardness. 
     As also illustrated in  FIG. 1 , a flexible silicone layer  106  is provided that is disposed in the hard plastic back shell  108 . The density of the flexible silicone layer ranges from 50 Shore A to 60 Shore A, but may vary from 30 to 70 Shore A. In one embodiment, a range of 48-52 Shore A is used. 
     The flexible silicone layer  106  is molded to fit directly into, and to conform closely to, the hard plastic back shell  108 . The flexible silicone layer  106  has a plurality of silicone layer openings  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 . Each of these silicone layer openings  130 - 144  is aligned with back shell hooks  114 - 128 , respectively. 
     Each of the back shell hooks  114 - 128  is recessed inwardly from the outer edge of the hard plastic back shell  108  so as to engage the silicone layer openings  130 - 144 . The back shell hooks  114 - 128  are inserted through the silicone layer openings  130 - 144  from the outside of the flexible silicone layer  106  and extend inwardly to the interior portion of the flexible silicone layer  106 . In this fashion, the back shell hooks  114 - 128  are disposed inside of the flexible silicone layer  106 , adjacent recessed portions, such as recessed portions  182 ,  184  in flexible silicone layer  106 , which allows the back shell hooks  114 - 128  to engage the back portion  110  of the sliding/articulating handheld electronic device  104 . 
     By inserting the recessed back shell hooks  114 - 128  through silicone layer openings  130 - 144 , the back shell hooks  114 - 128  are hidden by the flexible silicone layer  106  and a clean and decorative appearance is provided from the outside of the hard plastic back shell  108 . Also, since the back shell hooks  114 - 128  are recessed inwardly and the flexible silicone layer  106  is recessed outwardly, next to silicone layer openings  130 - 144 , such as recessed portions  182 ,  184 , there is little or no deflection of the flexible silicone layer  106  resulting from insertion of the back shell hooks, which further assists the combination of the hard plastic back shell  108  and the flexible silicone layer  106 , to function as a single integrated unit. 
     Upon assembly, the hard plastic back shell  108  and the flexible silicone layer  106  may be securely married together as a result of the mechanical connection between the recessed back shell hooks  114 - 128  and the silicone layer openings  130 - 144 , since the back shell hooks  114 - 128  are inserted through silicone layer openings  130 - 144 . In this manner, the flexible silicone layer  106  appears to be part of the hard plastic back shell  108  and functions as a single integrated unit. As a result, the flexible silicone layer  106  can be made from a soft, flexible material that is more easily capable of absorbing shocks since deformation and movement of the flexible silicone layer  106  away from the hard plastic back shell  108  is substantially restricted. 
     The back shell openings  152 - 160  are aligned with various portions of the flexible silicone layer  106 , as disclosed in more detail below. As also shown in  FIG. 1 , silicone layer operational features  180  are disposed in the flexible silicone layer  106  that are disposed in the back shell openings  152 - 160  when the flexible silicone layer  106  is married to the hard plastic back shell  108 . The silicone layer operational features  180  generically refer to the various pads, portals, access panels and other operational features of the flexible silicone layer  106 . 
       FIG. 2  is a schematic perspective view of the hard plastic back shell  108 . As illustrated in  FIG. 2 , the hard plastic back shell  108  includes a plurality of back shell hooks  114 - 128  that are recessed from the outer surface of the hard plastic back shell  108 . The back shell hooks  114 - 128  slide through the silicone layer openings  130 - 144  of flexible silicone layer  106  ( FIG. 1 ) and are hidden by the flexible silicone layer  106 . The silicone layer operational features  180  are disposed in the back shell openings  152 - 160 , as disclosed in more detail below, to prevent the entry of dust, dirt and moisture. 
       FIG. 3  is a schematic perspective view of the flexible silicone layer  106  disposed in the hard plastic back shell  108 . As shown in  FIG. 3 , back shell hooks  114 ,  116 ,  118  are inserted through silicone layer openings  130 ,  132 ,  134  in the flexible silicone layer  106 . Back shell hooks  114 ,  116 ,  118  are disposed on the interior portion of the flexible silicone layer  106  for attachment to the back portion  110  ( FIG. 1 ) of the sliding/articulating handheld electronic device  104  ( FIG. 1 ). Since the back shell hooks  114 - 118  are inserted through the silicone layer openings  130 - 134 , back shell hooks  114 - 118  are not visible from the exterior of the hard plastic back shell  108 . 
     For example, as illustrated in  FIG. 3 , back shell hooks  120 ,  122 ,  124 ,  126 ,  128  ( FIGS. 1 and 2 ) are not visible since the flexible silicone layer  106  hides the back shell hooks  120 - 128 , as illustrated in  FIG. 3 . In this manner, the flexible silicone layer  106  and hard plastic back shell  108  appear as a single integrated unit. Further, back shell hooks  114 - 128 , when inserted through silicone layer openings  130 - 144 , function to securely hold the flexible silicone layer  106  to the hard plastic back shell  108  so that the combined structure functions as a single integrated unit.  FIG. 3  also includes a pivoting access panel  178 , which provides access to a port on the back portion  110 . 
       FIG. 4  is an exploded view of the sliding/articulating handheld electronic device  104  that is aligned with the flexible silicone layer  106 , which is married to the hard plastic back shell  108 . As shown in  FIG. 4 , silicone pad  162  is disposed in back shell opening  152 . Similarly, silicone pads  164 ,  166  are disposed in the back shell opening  154 . Silicone pads  162 ,  164 ,  166  comprise silicone layer operational features  180  ( FIG. 1 ), as well as other operational features on the flexible silicone layer  106 , such as device buttons  186 ,  188  that are disclosed in  FIG. 1 . 
     The silicone layer operational features  180  interact with electronic device operational features  174 . Specifically, silicone pad  162  interacts with the device button  186 , while silicone pads  164 ,  166  interact with device button  188 . Another silicone layer operational feature  180  comprises the silicone plug  172  that is inserted in a jack (not shown) in the back portion  110  of the sliding/articulating handheld electronic device  104 . 
     As also illustrated in  FIG. 4 , the back shell hook  122  extends through the silicone layer opening  136 . Similarly, back shell hook  124  is inserted through the silicone layer opening  138 . Back shell hook  126  is similarly inserted through silicone layer opening  142 , while back shell hook  128  is inserted through silicone layer opening  144 . Each of the back shell hooks  114 - 128  ( FIGS. 1 and 4 ) attach to an inner surface of the back portion  110  of the sliding/articulating handheld electronic device  104  to securely hold the assembled flexible silicone layer  106  and hard plastic back shell  108  to the back portion  110  of the sliding/articulating handheld electronic device  104  without interfering with the sliding motion of the sliding/articulating front portion  112  ( FIGS. 1 and 4 ) of the sliding/articulating handheld electronic device  104 . 
       FIG. 5  is a schematic perspective view of the hard plastic front shell  102 . As shown in  FIG. 5 , front shell hooks  148 ,  150 , as well as other front shell hooks not illustrated in  FIG. 5 , securely attach to the sliding/articulating front portion  112  of the sliding/articulating handheld electronic device  104 . The hard plastic front shell  102 , as well as the front shell hooks, do not interfere with the sliding/articulating motion of the sliding/articulating front portion  112  of the sliding/articulating handheld electronic device  104 . 
       FIG. 6  is a schematic perspective view of an articulating handheld electronic device  600 . As shown in  FIG. 6 , the front portion  602  swivels away from the back portion  604  to expose a keyboard  606 . The front portion, as illustrated in the embodiment of  FIG. 6 , includes a display  608  that is disposed at an angle to the back portion  604  and keyboard  606  to assist in viewing the information on display  608 . The protective cover  100  ( FIG. 1 ) is attached to the front portion  602  and back portion  604  in a manner that does not impede the articulating movement of the front portion  602 . 
       FIG. 7  is a schematic perspective view of a sliding handheld electronic device  700 . As shown in  FIG. 7 , a front portion  702  slides away from a back portion  704  to expose the keyboard  706 . A hard plastic front shell, such as hard plastic front shell  102  ( FIG. 1 ), attaches to the front portion  702  and does not interfere with the movement of the front portion  702  with regard to the back portion  704 . Similarly, a hard plastic back shell and flexible silicone layer, such as hard plastic back shell  108  ( FIG. 1 ) and flexible silicone layer  106  ( FIG. 1 ), attach to the back portion  704  and do not interfere with the articulating movement of the front portion  702  of the sliding handheld electronic device  700 . 
       FIG. 8  is an exploded view of another embodiment of a protective case  800  and a sliding/articulating handheld device  804 . As illustrated in  FIG. 8 , a front flexible silicone layer  803  is disposed in hard plastic front shell  802 . The combined structure is then attached to the front portion  812  of the handheld electronic device  804  with front shell hooks  814 ,  816 ,  818 . The back flexible silicone layer  806  is disposed in the hard plastic back shell  808  and attaches to the back portion  810  of the handheld electronic device  804 , in the same manner as disclosed with respect to  FIG. 1 . 
     The protective case  800  provides additional protection to the front portion  812  of the handheld electronic device  804  as a result of the use of the combined structure of the hard plastic front shell  802  and front flexible silicone layer  803 . Hence, a flexible silicone layer is disposed under both the front plastic hard shell  802  and the hard plastic back shell  808  to provide additional protection to both the front portion  812  and the back portion  810  of the handheld electronic device  804 . 
       FIG. 9  is a schematic perspective view of an embodiment of a protective case  900  that may be used for a device with a hinge and where the flexible component of the protective case may cover or span the hinge area of the device. 
     As shown in  FIG. 9 , the protective cover  900  includes a front surface hard plastic outer cover  902  that snaps onto the front face of a handheld electronic device, such as a mobile phone. Similarly, a back surface hard plastic outer cover  904  snaps onto the back surface of the mobile phone, or other electronic device. 
     A silicone cover  922 , that is soft and flexible, has a front portion  920  that is disposed in the interior portion of the front surface hard plastic outer cover  902  and a back portion  906  that is disposed in back surface hard plastic outer cover  904 . A silicone hinge  908 , that connects front and back portions of the silicone layer, is disposed between the front surface hard plastic cover  902  and the back surface hard plastic outer cover  904 , and hinges along silicone fold line  910 . 
       FIG. 10  illustrates an example embodiment  900  that shows a protective cover in a partially open position. The protective cover may come in three parts: a front hard plastic cover  902 , a back hard plastic cover  904 , and a silicone hinge  908 . 
     In some embodiments, the silicone hinge  908  may be a separate, removable piece that is installed first, then the front cover  902  and back cover  904  may be installed on top of the silicone hinge  908 . 
     In other embodiments, the silicone hinge  908  may be molded to one or both of the front cover  902  and back cover  904 . In such an embodiment, the silicone hinge  908  may be overmolded onto the back cover  904  and/or the front cover  902 . Some embodiments may use a two-shot molding technique or a separate molding operation to mold the silicone hinge  908  onto one or both of the covers. 
     As shown in  FIG. 10 , the embodiment  900 , has a hinge  952  that hinges along the left vertical side  954  of handheld electronic device  950 . The embodiment  900  may be a protective cover for a cellular telephone or other handheld mobile device. Openings  912 ,  914 , illustrated in  FIG. 9 , allow a user to view activity and enter information into the electronic device. As also shown in  FIG. 9 , the silicone hinge  908  may include pads  916  that assist the user in entering information into the side of the handheld electronic device. The silicone hinge  908  provides protection to the left side edge  954  of the handheld electronic device and allows information to be entered into the handheld electronic device through pads  916  on the left side edge  954  of the handheld electronic device, while the protective case  900  and the handheld electronic device are in a closed position. 
     In other words, the silicone hinge  908  allows access to buttons  958  ( FIG. 10 ) on the side  954  of the handheld electronic device when the handheld electronic device and the protective case  900  are in a closed position, and the silicone hinge  908  provides protection to the side of the handheld electronic device adjacent to the silicone hinge  908 . Additionally, the front surface hard plastic outer cover  902  and the back surface hard plastic outer cover  904  provide additional protection from impacts and help disperse impacts throughout the softer silicone layer  922  that is disposed under the hard plastic covers  902 ,  904 . 
       FIG. 11  is a front view of the embodiment of  FIG. 9 . As shown in  FIG. 11 , the front surface hard plastic outer cover  902  has openings  912 ,  914 . The back portion  906  of the silicone inner cover  922  can be viewed through the openings  912 ,  914 . In addition, pads  916  are shown as part of the silicone hinge  908  that interface with buttons  958  on the handheld electronic device that is disposed in the protective case  900 . 
       FIG. 12  is a back view of the protective case  900 . As shown in  FIG. 12 , the back surface hard plastic outer cover  904  has an opening  918 . The front portion  920  of the silicone inner cover  922  that is disposed in an inner portion of the front surface hard plastic outer cover  902  is visible through the opening  918 . As also illustrated in  FIG. 3 , the back surface hard plastic outer layer  904  covers only a portion of the back surface, so that silicone hinge  908  is partially exposed. In this manner, silicone hinge  908  has a broad area to flex when the protective case  900  is in the open position. 
     Pads  916  allow activation of buttons  958  on the enclosed handheld electronic device while the protective case  900  is in the closed position. In this manner, the entire side of the enclosed electronic device is protected by the silicone hinge  908 , while the pads  916  allow access to the enclosed handheld electronic device. 
       FIG. 13  is an exploded view of the three pieces of the embodiment of  FIG. 9 . As shown in  FIG. 13 , the front surface hard plastic shell  902  is aligned to cover the front portion of the silicone cover  920 . The back surface hard plastic cover  904  is aligned to cover the back portion  906  of the silicone cover  922 . The silicone hinge  908  connects the front portion  922  to the back portion  906  of the silicone cover  922 . 
     Mechanical connectors  924  illustrate the manner in which the back surface hard plastic cover  904  attaches to the back portion  956  ( FIG. 10 ) of the handheld electronic device. Similarly, front surface hard plastic shell  902  includes similar mechanical connectors (not shown) that connect the front surface hard plastic shell  902  to the front portion  960  ( FIG. 10 ) of the handheld electronic device. 
     As illustrated in  FIG. 13 , the silicone cover  922  is a continuous cover that is disposed within the front surface hard plastic cover  902  and the back surface hard plastic cover  904 , and extends around the side of the handheld electronic device to provide protection to the front, back and side portions of the handheld electronic device. In this manner, protection is not only provided to the front and back faces, but also at the location where the handheld electronic device  950  hinges, as illustrated in  FIG. 10 , with a continuous silicone cover. 
     As disclosed above, the connecting silicone hinge  908  includes pads  916  ( FIG. 9 ) that allow activation of buttons  958  ( FIG. 10 ), while the protective case  900  is in a closed position. In this manner, the silicone cover  922  provides protection to the handheld electronic device and allows activation of buttons in the hinge area of the handheld electronic device. Further, the combination of the hard plastic covers  902 ,  904  that surround the softer silicone cover  922  provides a substantial amount of protection to the handheld electronic device that is not available from either the use of just a silicone cover or hard plastic covers. 
     The hard plastic covers  902 ,  904  protect the handheld electronic device from sharp impacts. The shock of hard impacts is spread along the surface of the hard plastic outer covers  902 ,  904 , and is absorbed by the silicone cover  922 . In this manner, the combination of the hard plastic covers  902 ,  904  and the silicone cover  922  provides both protection and accessibility that has not been available to hinged type of handheld electronic devices, such as flip phones. 
     Although the embodiment  900  is shown as a handheld electronic device that pivots along a side portion, a silicone hinge can also be provided on a top portion of a protective cover for handheld electronic devices that hinge along a top portion. Further, a silicone hinge can be provided along a bottom portion of the protective cover for handheld electronic devices that hinge along a bottom portion. Of course, the silicone hinge can be employed on either side of the protective cover, depending upon which side the electronic device hinges. 
     The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.