Patent Publication Number: US-2023133300-A1

Title: Pattern maker

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority to U.S. Provisional Application Ser. No. 63/272,805, filed on Oct. 28, 2021, which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     STATEMENT REGARDING JOINT RESEARCH AGREEMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a drawing device for creating a pre-determined pattern on a substrate. 
     2. Description of Related Art 
     Creating patterns using markers or other writing instruments is typically completed by hand. Children may create patterns on paper sheets for home-made wrapping paper, birthday cards and the like. The present disclosure aids in pattern-making by streamlining the process and allowing a more uniform outcome. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure is directed to a drawing device comprising at least one wheel coupled to a wheel rod having a gear assembly located thereon, wherein movement of the wheel causes rotation of the gear assembly, a cam operatively coupled to the gear assembly such that rotation of the gear assembly causes rotation of the cam, wherein the cam has at least one bearing surface that defines a pattern to be drawn by the drawing device, the bearing surface configured to intermittently engage a cam follower upon rotation of the cam, at least one arm operatively coupled to the cam follower, wherein the at least one arm is configured to pivot upon engagement of the cam with the cam follower, a marker carriage operatively coupled to the at least one arm, wherein the marker carriage defines at least one marker opening sized and shaped to receive a writing instrument, and wherein the marker carriage is configured to laterally move upon pivoting of the at least one arm in the pattern defined by the bearing surface. 
     The present disclosure is further directed to a kit comprising the drawing device as described above, at least two cams, and at least one writing instrument, wherein the at least two cams each have a bearing surface configured to define a pattern to be drawn by the drawing device and wherein the bearing surface of the first cam is different from the bearing surface of the second cam to define two different patterns. 
     The present disclosure is also directed to a method of creating a pattern on a substrate, the method comprising inserting at least one writing instrument into a marker carriage of a drawing device, coupling a cam to the drawing device, pushing the device across the substrate, wherein the device comprises at least one wheel coupled to a wheel rod, and the pushing causes the at least one wheel and the wheel rod to rotate, wherein the device comprises a gear assembly and rotation of the at least one wheel causes rotation of the gear assembly; wherein the gear assembly is operatively coupled to the cam, such that rotation of the gear assembly causes rotation of the cam, wherein the cam has at least one bearing surface configured to intermittently bear against a cam follower upon rotation of the cam, wherein the device further comprises at least one arm operatively coupled to the cam follower, wherein the at least one arm is configured to pivot upon engagement of the cam with the cam follower, and wherein the marker carriage is operatively coupled to the at least one arm and the marker carriage is configured to laterally move upon pivoting of the at least one arm. 
     Additional aspects of the invention, together with the advantages and novel features appurtenant thereto, will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Corresponding reference characters indicate corresponding parts throughout the drawings. 
         FIG.  1    is a perspective view of a drawing device in accordance with an embodiment of the invention showing markers and a cam mounted on the drawing device; 
         FIG.  2    is a perspective view of the drawing device of  FIG.  1    without the markers or cam mounted on the device; 
         FIG.  3    is a top plan view of the drawing device of  FIG.  1    without the markers but showing the cam mounted on the device; 
         FIG.  4    is a bottom plan view of the drawing device of  FIG.  1    without the markers mounted on the device; 
         FIG.  5    is a right side plan view of the drawing device of  FIG.  1    without the markers but showing the cam mounted on the device; 
         FIG.  6    is an exploded view of the drawing device of  FIG.  1    without the markers but showing the cam; 
         FIG.  7    is a perspective view of the bottom of the drawing device of  FIG.  1    with the bottom side of the housing removed; 
         FIG.  8    is a perspective cut-away view of the movement mechanism in combination with the gear assembly of the drawing device of  FIG.  1   ; 
         FIG.  9    is an exploded view of the gear mechanism of the drawing device of  FIG.  1   ; 
         FIG.  10    is a top perspective view of five different cams for use with the drawing device of  FIG.  1   ; 
         FIG.  11    is a bottom perspective view of the cams of  FIG.  10   ; 
         FIG.  12    is a perspective view of the cam follower, cam mount, biasing members, and arms of the drawing device of  FIG.  1   ; 
         FIG.  13    is a perspective view of an arm of the drawing device of  FIG.  1   ; 
         FIG.  14    is a bottom plan view of the top portion of the housing and the marker carriage of the drawing device of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     The present disclosure is generally directed to a drawing device. The drawing device is capable of creating patterns on a writing surface, particularly when the drawing device is pushed over the writing surface. Thus, the drawing device is capable of holding markers (or other appropriate writing instruments), and when the user pushes (or pulls or otherwise moves) the device over the writing surface (any sized writing surface), different line patterns are created. The patterns or designs created with this device can be used for a broad range of purposes, such as craft projects, wrapping paper, greeting or gift card paper, notebook covers, artwork, and the like. 
     One aspect of the present disclosure is directed to a drawing device shown in  FIGS.  1 - 14    and denoted by the numeral  10 . Looking to  FIGS.  1 ,  2  and  6   , drawing device  10  has a housing  12  that at least partially encloses a cam mount  14  onto which a cam  16  is mounted. Wheels  20  enable longitudinal (forward and rearward) movement of drawing device  10  by a user pushing or pulling on the device. As shown in  FIGS.  8  and  9   , movement of the device causes wheels  20  and wheel rod  22  to rotate, which in turn, causes gear  24  coupled to wheel rod  22  to rotate. Rotation of gear  24 , in turn, rotates worm screw  26 , which in turn rotates cam mount  14  and cam  16 . As shown in  FIGS.  7  and  12   , cam  16  contacts cam follower  28 , which pivots arms  30 . Arms  30  are coupled to marker carriage  32 , such that the pivoting movement of arms  30  translates to lateral movement of marker carriage  32 . 
     In various embodiments, housing  12  includes a top portion  12   a  and a bottom portion  12   b  that can be connected via any appropriate fastening mechanism  34  (e.g., fasteners such as screws, snap-fit closure, and the like), although access to the interior of the housing can be provided by a number of ways as will be understood by the skilled person. 
     Housing  12  has a movement mechanism located therein or thereon. In the illustrated embodiment, the movement mechanism includes two wheels  20  that partially extend through two holes  38  ( FIG.  4   ) defined by the bottom portion  12   b  of housing  12  so that they can contact a portion of the intended writing surface or substrate. In general, the movement mechanism allows for low friction contact between the writing surface and the base of the housing  12 . For example, the movement mechanism can include at least one wheel (e.g., one wheel, two wheels, three wheels, four wheels, etc.), or any other appropriate device. When at least one wheel is used, it can be coupled to the base of housing or, as illustrated, located partially within the housing  12  and partially extend through the bottom portion of the housing to contact the writing surface. When two wheels are used, as in the illustrated embodiment, the wheels  20  can be evenly spaced from a longitudinal axis al of the drawing device  10  as shown in  FIG.  4   . 
     Looking to  FIGS.  7  and  8   , the movement mechanism is operatively coupled to a gear assembly  40 , for example, by a rod  22  (wheel rod). In the illustrated embodiment having two wheels  20 , wheel rod  22  extends from the first wheel to the second wheel through a central portion of the respective wheels. Upon rotation of the wheels, the wheel rod  22  also rotates. A gear  24  is coupled to the wheel rod  22 . In the illustrated embodiment, the gear  24  defines a central hole  42  through which the wheel rod  22  extends, and the gear  24  is located at or near a center point of the wheel rod  22 . 
     Referring to  FIGS.  8  and  9   , the gear assembly  40  also includes a worm screw  26  operatively coupled to the gear  24  (worm wheel). Rotation of the gear  24  through rotation of the wheel rod  22  thereby also rotates the worm screw  26 . Worm screw  26  is located on a bottom portion of the cam mount  14 . Thus, rotation of worm screw  26  causes rotation of cam mount  14  as a whole. The device  10  also includes a gear holder  46  to aid in the interaction between the gear  24 , the worm screw  26  and cam mount  16 . The gear holder  46  has two pronged legs  48  that extend toward the wheel rod  22 . The cut-out portion creating the prong rests atop the wheel rod  22 , wherein one leg  48  is on one side of gear  24  and the other leg  48  is on the other side of gear  24 . The gear holder  46  can define openings  50  for insertion of fasteners (not shown) to fasten the gear holder to housing  12 . In the illustrated embodiment, the gear holder  46  contains three fastener openings  50  circumferentially spaced around gear holder  46 . In general, the gear holder is generally cylindrical in shape with an outwardly extending flange  52  and an inwardly extending flange  54 . The inwardly extending flange  54  mates with an outwardly extending flange  56  on the cam mount  14  to allow the cam mount  14  to rest atop the gear holder  46 , thereby allowing free rotation of the gear assembly  40  (worm wheel and worm screw). Pin  59  ( FIG.  9   ) can be inserted through an opening defined by gear holder  46  and worm screw  26  to operatively couple to components. 
     As shown in  FIG.  2   , cam mount  14  extends upwardly through a central opening in the top housing  12   a  such that a cam  16  selected by the user can be removably mounted on the cam mount. While in the illustrated embodiment, the cam mount is centrally located through the top of housing  12 , the skilled person will understand that the cam mount  14  can be located in any appropriate location on or in the housing  12  (e.g., on the top of, bottom of, sides of, or within the housing). The cam mount  14  includes a top mounting portion  58  and a bottom worm screw  26 . Thus, rotation of the worm screw  26  by the gear  24  propelled by the movement of the wheels  20  along a surface correspondingly causes rotation of the top mounting portion  58  of the cam mount  14 . 
     The mounting portion  58  has four upwardly extending sides  60 . Two opposing sides contain ribs  62 . In the illustrated embodiment, these sides  60  are supported via a support wall  64  to strengthen the cam mount  14  from one rib  62  to the other rib  62 . The other two opposing sides contain a central tab  66 , wherein the tab  66  is resiliently deflectable. The central tab  66  contains a detent  68  to secure the cam  16  to the cam mount  14 . Thus, the mounting portion  58  generally resembles a protruding square having four perpendicular sides. Referring to  FIGS.  10  and  11   , the underside of the cam  16  mimics this structure, having an analogous recessed portion  70  having the same general shape as the protruding mounting portion  58 . Thus, two opposing sides of the recessed square contain outward bulges  72  that mate with the outwardly projecting ribs  62  of the mounting portion  58  of the cam mount  14 . The top wall of the cam  16  defines two openings  74  on the inner side of the two other opposing side walls corresponding to the deflectable tabs  66  of the cam mount  14 . The deflectable tabs  66  mate with these openings  74  to releasably couple the cam  16  to the cam mount  14 . 
     As shown in  FIGS.  10  and  11   , the cam  16  can be any desired shape and a variety of different shapes of cams may be provided for use with the drawing device to make different patterns. As discussed more fully below, the shape of the cam dictates the translational movement of the marker carriage  32 . That is, the shape of the cam dictates the overall pattern made upon movement of the device  10 . As illustrated, the cam can also include a peripheral skirt  78  that contacts the internal walls of the cam follower  28 . 
     As best shown in  FIGS.  3  and  12   , a collar shaped cam follower  28  is positioned adjacent cam mount  14  and cam  16  for contact with cam  16  upon movement of the drawing device. Cam follower  28  has an arcuate shape so that one end  28   a  of the cam follower is located to one side of the cam mount (e.g., left side) and the other end  28   b  of the cam follower is located to the other side of the cam mount  14 , opposing the other end of the cam follower (e.g., right side). Cam follower  28  is coupled to housing at a pivot point p such that cam follower  28  pivots upon contact of the cam  16  with the cam follower  28 . The top side of the housing  12   a  can also contain a cam frame  82  ( FIGS.  2  and  3   ) to generally hide the cam follower from view of the user. 
     Looking to  FIGS.  6 ,  7  and  12   , cam follower  28  is operatively coupled to arms  30 ( a )( b ) via corresponding linkages  84 ( a )( b ). Linkages  84 ( a )( b ) are coupled to cam follower  28  through corresponding fastener openings  90 ( a )( b ) defined by cam follower as well as arcuate openings  86 ( a )( b ) ( FIG.  14   ) in housing  12 . Arcuate openings  86  are sized to allow for the pivoting movement of the cam follower  28  to be mimicked by the linkage  84 . A fastener  88  can be inserted into the cam follower fastener opening  90  and threaded into a fastener hole defined by linkage  84  thereby coupling cam follower  28  to linkage  84 . The skilled person will understand that cam follower  28  can be coupled to linkage  84  in other appropriate manners. Cam follower  28  (and linkage  84 ) may be coupled to arms  30  at a number of locations. In the illustrated embodiment, both the first end of the cam follower  80   a  and the second end of the cam follower  80 b define a fastener opening  90  coupled to a first linkage and a second linkage. Alternatively, the cam follower  28  can define at least one fastener opening (for example, one fastener opening, two fastener opening, three fastener openings, four fastener openings, etc.) with a fastener inserted therethrough and coupled to a linkage at any appropriate location. 
     Linkages  84 ( a )( b ) are operatively coupled to arms  30 ( a )( b ). Linkages  84  can be coupled to arms  30  through fastener holes defined by arms  30 . A fastener can be inserted into each arm  30  and threaded into a fastener hole defined by each linkage  84 , thereby coupling arms  30  to linkages  84 . Alternatively, linkages  84 ( a )( b ) may be integrally formed with arms  30 ( a )( b ). The skilled person will understand that arm  30  can be coupled to linkage  84  in other appropriate manners. The illustrated embodiment contains an arm  30  at each linkage  84 . Arms  30  are connected to each other via stability leg  92  to provide added stability, although the skilled person will understand that added stability may not be necessary, or can be provided in a variety of other manners. The stability leg  92  defines fastener openings  94 ( a )( b ) that correspond to the fastener openings defined by arms  30 . Thus, when a fastener is placed through an end of the stability leg  92 , an arm  30  and linkage  84 , it couples these three components together. 
     In various embodiments, the drawing device  10  may include more than one cam follower operatively connected to arms  30 . A second cam follower can be located, for example, on the top and bottom of cam mount, so that there is a cam follower on each of the top, bottom, left, and right of cam mount. In embodiments having a first cam follower and a second cam follower, the first cam follower can create side-to-side movement of a marker holding assembly, and the second cam follower can create front-to-back movement of the marker holding assembly. Alternatively, a first cam follower can be located to one side of the cam mount (e.g., left side) and a second cam follower can be located to the other side of the cam mount, opposing the first cam follower (e.g., right side). In various embodiments, the device can also comprise a third cam follower located approximately 90 degrees from and general planar to the first and second cam follower (e.g., on the top side of cam mount) and a fourth cam follower opposing the third cam follower (e.g., on the bottom side of the cam mount). 
     In various embodiments, and referring in particular to  FIGS.  7  and  12   , biasing members  100 ( a )( b ) can couple corresponding arms  30 ( a )( b ) to housing  12 . In the illustrated embodiment, an end of a biasing member  100  (e.g., spring) is coupled to one of the arms  30  via a fastener  102  through a biasing member fastener hole  104  ( FIG.  13   ) defined by arm  30 . The other end of the biasing member  100  (e.g., spring) is coupled to a post  106  in housing  12  via a fastener. The biasing members  100  allow the arms  30  to return to a neutral (starting) position after a pivoting movement caused by movement of the cam follower  28 . 
     In the illustrated embodiment, and referring in particular to  FIG.  14   , each arm  30  contains three distinct portions. A first portion  31   a  of the arm is generally located in an upper portion of the housing  12  above the wheel rod  22  and is generally planar and parallel to the longitudinal axis al of the drawing device  10 . A second portion  31   b  of the arm  30  extends perpendicularly downward toward the bottom of housing  12  and terminates below wheel rod  22 . A third portion  31   c  of the arm  30  extends parallel to and in the same direction as the first portion  31   a  and below the wheel rod  22  and couples the arms  30  to the marker carriage  32 . The arms  30  can be coupled to the marker carriage  32  through any known means in the art, for example, using fasteners placed through fasteners holes defined by the marker carriage  32  and the arms  30 . 
     Looking to  FIG.  14   , the marker carriage  32  contains an elongated slot  110  located thereon that mates with a protrusion  112  having two fastener holes  114  defined on either side thereof protruding downward from the top portion  12   a  of the housing  12 . The elongated slot  110  is wide enough to allow the protrusion  112  to pass therethrough but not allow passage of the heads of any screw inserted into the fastener hole, thereby securing the marker carriage to the housing. The elongated slot has a length l 1  greater than the length l 2  of the housing protrusion. The difference in length allows for lateral side-to-side movement of the marker carriage upon pivoting of the arms from the cam follower movement and cam rotation. 
     The marker carriage  32  has a first portion  33   a  and a second portion  33   b . The first portion  33   a  can be partially or completely enclosed within housing  12 . The first portion  33   a  is generally co-axial with the housing  12  (e.g., the base of housing). The second portion  33   b  of the marker carriage  32  is generally angled relative to the first portion of carriage  33   a . For example, the second portion can be angled about 145 degrees to about 155 degrees (e.g., 150 degrees) relative to the first portion and to the housing. In other embodiments, the second portion  33   b  is co-axial with the first portion  33   a . The degree of angle of the second portion may dictate the relative line thickness of the markings produced upon movement of the drawing device  10 , especially when a marker having a bullet nib is used. For example, a second portion that is not angled or not substantially angled relative to the first portion will produce a thinner line as compared to a second portion that is angled at least 45 degrees relative to the first portion. 
     The second portion  33   b  of marker carriage  32  defines at least one opening  120 . The opening  120  is sized to receive a marker or other writing instrument as intended. For example, the opening  120  can be sized to receive a broad line marker, a fine line marker, or a super fine line marker, a crayon, a pen, a pencil, or any other appropriate writing instrument. In embodiments where the opening is sized to receive a marker, the opening is generally sized to allow the nib of the marker to pass through while not allowing the barrel of the marker to pass. In various embodiments, the opening can be universally sized to receive a variety of different writing instruments. In other embodiments, the opening can be sized to receive a particular writing instrument. In various aspects, the opening may be sized and shaped to provide a snap fit with the top of the marker barrel. 
     Marker carriage  32  can define more than one opening  120 , for example, two openings, three openings, four openings, five openings, six openings, seven openings, eight openings, nine openings, ten openings, or more. The number of openings for writing instruments can be increased through an expansion member having additional openings located thereon that can be coupled to the body of the marker holding assembly. The illustrated embodiment defines ten openings  120  for engagement of ten different markers. 
     In various embodiments, first portion  33   a  is offset from second portion  33   b  by ledge  126 . The barrel of the marker or other writing instrument rests on ledge  126  to provide stability to the writing instrument. The ledge  126  can be sized and shaped to correspond to the size and shape of the barrel of the writing instrument in order to essentially cradle the barrel during use. An upwardly extending wall  128  is positioned on either side of each opening  120  in the marker carriage  30  to provide added stability to the writing instrument once inserted. The spacing between walls  128  can be such that the distance between adjacent walls  128  is substantially equal to or only slightly larger than that of the writing instrument intended to be used in the marker carriage. For example, when the openings  120  are sized for use with a broad line marker, the distance between adjacent walls  128  is generally about the diameter of the barrel of a broad line marker, such that the outer surface of the barrel of the marker (or other writing instrument) is in abutting engagement (contact with) the walls on either side of the opening through which the marker is inserted. The walls  128  can also contain upwardly extending ribs  130  and/or nibs  132  along a portion thereof in order to increase contact with the inserted writing instrument. In the illustrated embodiment, two ribs  130  are located on a front portion of the wall  128  on each marker-contacting surface and a nib  132  is located on a top rear portion of the wall  128  on each marker-contacting surface. The walls  128  are generally trapezoidal in shape, having a flat bottom side, generally perpendicular front and back sides, wherein the back side is taller than (extends more upward than) the front side. A top side connects the back side to the front side and is generally angled due to the disparity in side lengths of the back side and the front side. 
     The carriage  32  can comprise an adapter (not shown) that is coupled to the opening (for example, through a snap fit or mating mechanism) so that the opening is sized to receive a writing instrument of a different size. For example, the openings can be sized to receive a broad line marker (or any other desired writing instrument), or upon engagement of the adapter, a fine line marker (or any other desired writing instrument). Different adapters can be used to change the size of the opening. For example, one adapter can change the size of the opening to receive a fine line marker. A second adapter can the size of the opening to receive a crayon, and so forth. The adapter can have a component that also adapts the wall spacing to allow for abutting engagement of different sized writing instruments with the walls. For example, the adapter can have walls connected thereto that extend relatively upward to engage a writing instrument barrel inserted therein. Alternatively, the wall spacing adapter can be a separate component. For example, a wall spacing adapter can be coupled to existing walls independently (e.g., through snap fit, mating components, etc.). 
     Looking to  FIG.  4   , a deployable positioning wheel  128  can be located on the base of housing  12 . The positioning wheel  128  is movable (retractable) from a first deployed position to a depressed position. In the first position, the positioning wheel  128  elevates the housing  12  by raising a portion of housing  12  (e.g., tilting housing near the marker holding assembly) to allow markers or other writing instruments to be inserted into the marker carriage  32  without unintentional markings on the writing surface. In use, the positioning wheel  128  is pushed into a retracted position, thereby moving the writing instruments into contact with the writing surface. The positioning wheel  128  also provides a third wheel surface for added stability of the device  10  while moving. 
     In another embodiment, a retractable spacer (not shown) can be used in place of or in addition to the positioning wheel. In this way, the spacer can be deployed so that it elevates housing by raising at least a portion of housing to allow markers or other writing instruments to be inserted into the marker carriage. The retractable spacer can be retracted, for example by moving the spacer so that it is generally flush with the base of housing or in a position so as not to cause interference between the retractable spacer and the writing surface. 
     In use, a user inserts a desired cam (using the pattern indicia located thereon to determine the pattern) into the cam mount. The user inserts the desired writing instruments into the openings defined by the marker carriage. The user then pushes the device across a substrate to create a design. That is, the movement of the device causes the writing instrument to create a line (a patterned line) across the surface of the substrate. By moving the device, the wheels rotate, causing the wheel rod to rotate. The rotation of the wheel rod rotates the gear assembly (the gear and the worm screw) to thereby cause rotation of the cam and the cam mount. The rotation of the cam causes intermittent contact of the cam with the cam follower (e.g., the left side and/or right side of the cam follower on an intermittent basis). The cam follower movement causes the arms of the device to pivot, which thereby translationally moves the marker carriage. The marker carriage movement causes the lines created on the substrate from the writing instrument to one side of center. The particular shape of the cam will dictate the pattern. For example, a cam having more contact surfaces for contact with the cam follower, evenly distributed across the perimeter of the cam will cause rapid side-to-side movement of the marker carriage due to the rapid contact of the cam with the left and right sides of the cam follower. This shape of cam may create, for example, a large (high-amplitude) high-frequency zig-zag pattern. When the protrusions on the cam perimeter are reduced, but the same general shape is used, a smaller (low-amplitude) high-frequency zig-zag pattern may be created. Thus, the fewer protrusions present on the circumference of the cam will cause less translational movement of the markers during the creation of the pattern (a lower frequency pattern), and more protrusions will cause more translational movement (a higher frequency pattern). Similarly, the larger the distance from the main cam body to the end of the protrusion (i.e., a cam having larger protrusions), the larger the amplitude of the created pattern, and the smaller the distance, the smaller the amplitude of the created pattern. For example, a centered circle will produce a relatively straight line as it does not contact the cam follower(s), whereas an off-centered circle (having one cam protrusion) will produce a wavy line and a star shape will produce a zig-zag line. Pattern indicia  76  ( FIG.  10   ) located on the cam  16  indicate the pattern that will be produced by that particular cam  16 . The pattern indicia  76  can include a raised example of the pattern. For example, a triangular cam having side indents includes a high-amplitude zig-zag pattern raised on the top side of the cam. A star-shaped came includes a low-amplitude zig-zag pattern raised on the top side of the cam. 
     From the foregoing it will be seen that this invention is one well adapted to attain all ends and objectives herein-above set forth, together with the other advantages which are obvious and which are inherent to the invention. 
     Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative, and not in a limiting sense. 
     While specific embodiments have been shown and discussed, various modifications may of course be made, and the invention is not limited to the specific forms or arrangement of parts and steps described herein, except insofar as such limitations are included in the following claims. Further, it will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.