Abstract:
A standable sticker is provided comprising an integral one-piece shape that is divided into a figure portion and a base portion. The base portion is adapted for permanent or removable adherence to a surface, and is coated on one side with a pressure sensitive adhesive. A perforated or scored line defines a boundary between the figure portion and base portion and the figure portion in foldable at an angle to the base portion at the perforated or scored line to permit the figure portion to be presented in a substantially vertical orientation. The sticker is adapted for releasable adhesion to liner material or substrate.

Description:
TECHNICAL FIELD 
     The present invention relates to pressure sensitive stickers having graphic designs and, more particularly, to stickers that are standable on a surface so as to present an erect, three-dimensional perspective of the graphic designs, and stickers that may be either permanently adherable to the surface or removable from and reattachable to the surface. 
     BACKGROUND OF THE INVENTION 
     Stickers have a wide variety of informational, educational and entertaining uses, particularly for children. Conventionally, stickers are effectively two-dimensional from a perspective view in that they lay flat when adhered to a surface. For some purposes such as creating a diorama having depth and perspective, however, it is desirable to present stickers in a three-dimensional manner. That is, there is a need for stickers that have graphic designs printed thereon and are self-standable in a substantially vertical orientation. There is also a need for self-standable stickers that are repositionable on a surface without sacrificing their adherent characteristics. The present invention provides standable, pressure sensitive stickers for permanent or repositionable adherence to a display surface, and methods and apparatus for manufacturing them. 
     SUMMARY OF THE INVENTION 
     A standable sticker is provided comprising an integral one-piece shape that is divided into a figure portion and a base portion. The base portion is adapted for adherence to a surface, and is coated on one side with a pressure sensitive adhesive. A perforated or scored line defines a boundary between the figure portion and the base portion, and the figure portion is foldable at an angle to the base portion at the defined line. This permits the figure to be presented in a substantially vertical orientation. 
     In another embodiment, a group of stickers are provided on a liner material or substrate. The stickers are adapted to be released from the liner material and transferred to a coated display surface on which the stickers may be arranged in repositionable configurations. 
     The present invention also provides processes for manufacturing the stickers described above. In a first process, a length of base material is passed through an adhesive coater to apply one or more pressure sensitive adhesive strips to a first side of the base material, such that the first side has a non-adhesive region adjacent the adhesive strip or strips. A laminate is produced by applying a length of releasable liner material to the first side. The laminate is either passed through a corona treater or chemically treated in a top-coating process, to permit a second side of the base material to accept ink. The laminate is then passed through one or more print decks to create one or more images on the non-adhesive region. The laminate subsequently undergoes a series of finishing steps. A die-cutting station produces outlines on the laminate. Each outline circumscribes an image that defines a figure portion and an area of the adhesive strip that defines a base portion. The same die-cutting station also produces perforated lines along an edge defined between the non-adhesive region and the adhesive strip. Alternatively, a separate scoring station produces scored lines. A sheeting station cuts the length of laminate into discrete sheets. 
     In a second process for manufacturing standable stickers, a length of base material is either passed through a corona treater or chemically treated in a top-coating process to permit a print side of the base material to accept ink. The base material is passed through one or more print decks to create predetermined images on the print side, each image defining a figure portion. The base material is then passed through a coating station to apply a pattern of pressure sensitive adhesive coating to predetermined regions of a first side of the base material. Each region defines a base portion, and each base portion abuts an edge of a corresponding one of the figure portions. A laminate is produced by applying a length of releasable liner material to the first side. The laminate is passed through a die-cutting station to cut outlines into the base material. Each outline defines a sticker, and each sticker includes one of the figure portions and a corresponding one of the base portions, with pressure sensitive adhesive on the base portion but not on the figure portion. Perforated or scored lines are produced on the laminate as in the first method, each score line being one of demarcation and substantially coincident with a corresponding one of the edges of the figure portions. A sheeting station is then employed to cut the laminate into discrete sheets. 
     In another process for manufacturing standable stickers, a length of base material is passed through a print deck to print predetermined images on a back side of the base material. Die patterns are then produced on a front side of the base material. The die patterns are in register with corresponding images on the back side. A composite is produced by applying a length of laminate material to the back side of the base material. A pattern of pressure sensitive adhesive regions is applied to the laminate material. A length of releasable liner material is then applied to the laminate material. The composite is passed through a die-cutter to define figure portions and corresponding base portions on the composite. Each figure portion includes at least one of the graphic images, and each base portion includes one of the adhesive regions. A plurality of perforated or scored lines are produced on the composite. Each line defines a boundary between one of the figure portions and a corresponding one of the base portions. The composite is then cut into a finished sheet having a total area less than a total area of the initial sheet. 
     The present invention is also directed to apparatus employed in the practice of the processes herein described. 
     Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a sticker according to the present invention; 
     FIG. 2 is a perspective view of the sticker of FIG. 1 in a standing position; 
     FIG. 3 is a top view of a set of stickers positioned on a substrate according to the present invention; 
     FIG. 4 is a perspective view of a group of stickers arranged on a coated surface; 
     FIG. 5 is a diagrammatic view of adhesive coating apparatus in operation according to a first method of the present invention; 
     FIG. 6 is a view of the back side of a base material with adhesive stripping according to the first method of the present invention; 
     FIG. 7 is a diagrammatic view of a flexographic printing and finishing apparatus in operation according to the first method of the present invention; 
     FIG. 8 is a view of the front side of a base material showing rows of graphic images printed thereon according to the first method of the present invention; 
     FIG. 9 is a view of the front side of the base material of FIG. 8 showing die-cut outlines and perforated or scored lines; 
     FIG. 10 is a diagrammatic view of a sticker constructed according to the first method of the present invention showing the relationships between layers, adhesive coating and color applications; 
     FIG. 11 is a perspective view of the sticker of FIG. 10 shown in a standing position; 
     FIG. 12 is a diagrammatic view of in-line apparatus for producing stickers according to a second method of the present invention; 
     FIG. 13 is a view of the front side of a base material with a set of graphic images printed thereon according to the second method of the invention; 
     FIG. 14 is a view of the front side of the base material of FIG. 13 showing die-cut outlines and perforated or scored lines; 
     FIG. 15 is a diagrammatic view of offset lithographic apparatus in operation according to a third method of the present invention; 
     FIG. 16 is a view of the back side of a base material with graphic images printed thereon according to the third method of the present invention; 
     FIG. 17 is a diagrammatic view of a die pattern station in operation according to the third method of the present invention; 
     FIG. 18 is a view of the front side of a base material with die patterns printed thereon according to the third method of the present invention; 
     FIG. 19 is a diagrammatic view of a laminating machine in operation according to the third method of the present invention; 
     FIG. 20 is a diagrammatic view of adhesive application apparatus in operation according to the third method of the present invention; 
     FIG. 21 is a diagrammatic view of liner material application apparatus in operation according to the third method of the present invention; 
     FIG. 22 is a view of the back side of a base material according to the third method of the present invention showing a base material, laminate layer, a pattern pressure sensitive adhesive application, and a liner material; 
     FIG. 23 is a diagrammatic view of die-cutting and scoring apparatus in operation according to the third method of the present invention; 
     FIG. 24 is a diagrammatic view of sheet cutting apparatus in operation according to the third method of the present invention; 
     FIG. 25 is a front view of a laminated sheet having die-cut outlines and perforated or scored lines according to the third method of the present invention; and, 
     FIG. 26 is a diagrammatic view of a sticker constructed according to the third method of the present invention showing the relationships between layers, adhesive coating and color applications. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. 
     FIGS. 1 and 2 show a sticker according to a preferred embodiment of the present invention. The sticker  10  includes a printed figure or graphic design portion  12  designed for presentation in a standing orientation, such as a substantially vertical position with respect to a horizontal. The sticker  10  may be constructed of a cellulosic based (i.e., paper), a polymeric based (i.e., plastic) material, a composite thereof, and is preferably rigid. Various types of objects, characters or text may be printed on the figure portion  12 . In addition, the figure portion  12  has a die-cut outline or periphery  14 , the shape of which is chosen as appropriate to enhance the image or information printed on the figure portion  12 . Integral with the figure portion  12  is a tab or base portion  16 . A perforated or scored line  18  defines a boundary between the figure portion  12  and base portion  16 . Preferably, the line  18  is perforated with one or more perforations rather than scored. The sticker  10  is adhered to a substrate or liner material  20  that serves as a storage or holding medium. The sticker  10  is removable from the liner material  20 . Silicone treated paper has been found suitable for use as the liner material  20 . 
     To present the sticker  10  in a substantially vertical orientation, i.e., in a three-dimensional manner, the sticker  10  is peeled from the liner material  20 . The base portion  16  is folded at an angle from the figure portion  12  at the perforated or scored line  18  such that the base portion  16  serves as a supporting base or foot for the figure portion  12 . In the embodiment shown in FIGS. 1 and 2, one side  22  of the base portion  16  is treated with a pressure sensitive adhesive and the sticker  10  is placed on a display surface  24 . To facilitate and enhance the free-standability of the sticker  10 , the display surface is preferably coated with an aqueous coating and a top liquid coating such as unsaturated oligomeric acrylate that is photo initiated, i.e., cured by an ultraviolet (“U.V.”) source. This material is distributed by Kelstar in Cinnaminson, N.J., under the trade name “Ultra Sheen”, Model No. UV-32EC. The sticker  10  may be repeatedly removed from the liner material  20 , folded at the score line  18 , placed on the coated surface  24 , removed from the coated surface  24 , unfolded and returned to the liner material  20 . 
     FIGS. 3 and 4 show another preferred embodiment according to the present invention. A plurality of stickers  10  are provided as a thematically-related, integrated set on one or more sheets of liner material  20 . The stickers  10  have varied sizes, images, and die-cut shapes or outlines  14 . The stickers  10  are removable from the liner material  20  and positionable in various combinations on the coated display surface  24  provided with the stickers  10 . The display surface  24  may be printed in a background scenario or graphic format consistent with the theme expressed by the graphic images or text of the stickers  10 . As with the embodiment illustrated in FIGS. 1 and 2, the coating on the display surface  24  permits the stickers  10  to be repeatedly adhered and removed therefrom. Thus, a user may create various customized dioramas on the display surface  24  by repositioning and rearranging the stickers  10  a number of times. 
     Production Methods 
     Three preferred production methods for manufacturing the stickers  10  according to the present invention will now be described. The first and second methods take advantage of flexographic printing technology which enables printing with line screens of 133-150 dpi; the process is competitive with offset lithography line screens of 175-200 dpi. Generally, the first method is a two-step method that involves flexographic production on converted material. The second method is a one-step method that involves flexographic production with in-line adhesive coating. The third method contemplates offset printing combined with silk screen adhesive application and off-line finishing. 
     Method 1 
     Method 1 relies on flexographic production, which offers the intrinsic advantages of full color printing on a wide variety of possible substrates other than paper, as well as many different possible finishing operations. All steps involved may be accomplished in-line, preferably using rolls of material, but may generally be divided into two processes: a converting process and a flexographic printing process. 
     FIG. 5 illustrates the converting process and apparatus used therefor. A roll  30  of a base material  32  is provided. The base material  32  is preferably a clear plastic such as polyester having a thickness of five mils. A length of the base material  32  is unrolled and passed through an adhesive coater  34 , which applies one or more longitudinal strips of pressure sensitive adhesive  36  to the back side  38  of the base material  32 . As shown in FIG. 6, application of the adhesive results in the back side  38  having alternating adhesive strips  36  and non-adhesive areas or regions  40 . In order to provide a substrate for the base material  32 , a length of releasable liner material  20  is fed from a roll  44  to a pair of rollers  46  and applied to the back side  38  of the base material  32  to produce a laminate  48 . The laminate  48  is then collected into a roll  50  and ready to be transferred to the flexographic printing process. 
     FIG. 7 illustrates the flexographic printing process which, in the preferred embodiment, also includes the finishing steps described below. It is generally difficult to adhere ink to the base material  32  which, as described above, is preferably a plastic, because plastic is nonporous. Thus, a length of the laminate  48  is fed from the roll  50  through a corona treater  52  to apply a static electrical charge to the front or print side  54  of the base material  32  in order to enhance the ability of the print side  54  to accept ink printing. An alternative to employing the corona treater  52  is to chemically treat the print side  54  to accept ink ,i.e., “top coating” the print side with an overprint varnish such as one containing isopropyl alcohol and aqua ammonia. Using the corona treater  52 , however, has been found to be more economical in the practice of the present invention. 
     The laminate  48  is then passed through at least one, but preferably a series of, print decks  56 , 58 , 60 , 62 , 64  to print predetermined information, figures or graphic images  66  on the print side  54 . Each print deck  56 , 58 , 60 , 62 , 64  applies a single color of ink. As printed, the images  66  are reversed or mirrored —that is, the images  66  are created “face-down” with respect to the base material  32 . Hence, when the finished sticker  10  is folded at the perforated or scored line  18  and vertically disposed in its standing position as shown in FIG. 11, the images  66  appear in correct orientation when viewed through the clear base material  32  in its finished state. Preferably, the last print deck, e.g., print deck  64  in the present embodiment, should overlay a white-colored ink application over the entire surface to increase opacity and create stronger viewing graphics. As shown in FIG. 8, the images  66  are created only on the non-adhesive regions  40  of the print side  54 , and may vary with respect to size, shape and graphic design in a predetermined, repeatable pattern. 
     Once the printing process has been completed, the laminate  48  may, if required or desired, be run through an over-laminate station  68  to apply a clear over-laminate layer  70  to the print side  54  of the base material  32 . The over-laminate layer  70  may serve to protect non-U.V. treated ink or to otherwise enhance quality and durability. In addition, the glossy surface of the over-laminate layer  70  may be considered to improve the aesthetic effects of the finished product. 
     The printed laminate  48  is then subject to a series of finishing steps. The laminate  48  is passed through a diecutting station  72 . As shown in FIG. 9, the die-cutting station  72  cuts outlines  14  into the base material  32  from its print side  54  about the periphery of the images  66  printed thereon to define figure portions  12 . The outlines  14  are also cut into areas of the print side  54  directly opposite from the adhesive strips  36  on the back side  38  of the base material  32  to define base portions  16  immediately adjacent the figure portions  12 , as also shown in FIG.  9 . Although not shown in the Figures, it is preferable that the die or dies used to cut the outlines  14  be nicked so as to leave a narrow, continuous bridge of base material  32  joining each figure portion  12  to the uncut regions of the laminate  48 . Such bridges afford the stickers  10  with a point of attachment to the laminate  48 , thereby eliminating possible subsequent quality control problems, without affecting the ability of the end user to peel the finished stickers  10  from the liner material  20 . 
     The die-cutting station  72  also creates perforated lines  18  between each corresponding pair of figure and base portions  12 , 16  to facilitate the foldability of the finished stickers  10 . While the number of perforations will depend on the length of the line  18 , it has been found sufficient to punch one or two perforations along the line  18 . As an alternative to perforating the line  18  at the die-cutting station  72 , the laminate  48  may be passed through a scoring station  78  that imparts a score along each line  18 . However, perforating the line  18  is preferable since this eliminates the need for the scoring station  78 . Also, better quality control has been observed in high-volume production runs when perforating is chosen in favor of scoring. 
     Finally, the laminate  48  is passed through a sheeting station  82  to create a plurality of laminate sheets  84  each having an identical grouping or arrangement of stickers  10 . As described previously, each sheet  84  should contain a set of thematically related stickers  10 . The sheets  84  will each have a length of 7.25″ and a width of 4″. 
     FIG. 10 diagrammatically summarizes the construction of the finished sticker  10  with its several layers shown in exploded view. As described, the base portion  16  of the base material  32  has an adhesive coating  86  cut from one of the adhesive strips  36 . The several applications of ink colors  88  result in the figure or graphic image  66  imprinted on the figure portion  12 . The finished sticker  10  is produced with the liner material  20  in releasable contact with the base portion  32 . 
     It will be understood that as an alternative to employing discrete converting and flexographic printing processes, both processes may be carried out as a single, continuous, in-line process wherein the step of transferring the roll of converted laminate  50  from the converting equipment to the printing equipment is eliminated. The election of the one alternative in preference to the other will depend upon a number of factors having little immediate relevance to the present invention. However, both alternatives are intended to come within the scope of the invention. 
     Method 2 
     As with Method 1, Method 2 relies on flexographic production. However, Method 2 is more specifically intended to produce the stickers of the present invention in a single, continuous, in-line process. 
     As shown in FIG. 12, a length of base material  32 , preferably a clear, rigid plastic, is passed through flexographic printing apparatus similar to that used in Method 1 described above. That is, the corona treater  52  and one or more print decks  56 , 58 , 60 , 62 , 64  are employed to imprint informational or graphic images  66  on the base material  32 , preferably at a resolution of 133-150 line screens. Again, the images  66  are printed in reversed or mirrored fashion so as to appear in correct form when the finished sticker  10  is displayed as in FIG.  11 . The resulting set of images  66  printed on the top or print side  54  may differ in size, shape and graphic design, as shown in FIG. 13, and are grouped in predetermined, repeated patterns. As in Method 1, the corona treater  52  will be eliminated in the case where the print side  54  has been chemically treated to accept ink. 
     The printed base material  32  is then run through a pattern coating station  90  which applies a plurality of pressure sensitive adhesive coatings  86  to the back side  38  of the base material in a predetermined pattern corresponding to the images  66 . In FIG. 13, reference numeral “ 92 ” designates the locations on the base material  32  at which the adhesive coatings  86  are applied in adjacent relation to the images  66 . A releasable liner  20  comparable to that employed in Method 1 is then fed from a roll  44  to a pair of rollers  46  and applied to the back side  38  of the base material  32  to produce a laminate  94 . As in Method 1, it may be desirable or necessary at this point to utilize an over-laminate station  68  to apply a clear over-laminate layer  70  to the print side  54 . 
     The subsequent finishing steps are analogous to those employed in Method 1, i.e., passing the laminate  94  through a die-cutting station  72  and a sheeting station  82 . As before, the scoring station  78  is necessary only where the die-cutting station  72  has not been configured to produce perforations on the lines  18 . In addition, the die or dies used at the die-cutting station  72  may be nicked so as to leave a narrow, continuous bridge (not shown) of the base material  32  joining each figure portion  12  to the uncut regions of the laminate  94 . The resulting plurality of sheets  96  produced, shown in FIG. 14, include die-cut outlines  14  defining corresponding figure and base portions  12 , 16  separated by perforated or scored lines  18 . The sheets  96  will typically each have a length of 7.25″ and a width of 4″. The construction of the finished stickers  10  may be diagrammatically summarized in a manner analogous to that depicted in FIG. 10 with respect to Method 1. 
     The one-step, in-line method of Method 2 provides certain advantages over Method 1. The ability to pattern coat pressure sensitive adhesive onto the base material  32  in-line while performing the printing steps lowers production costs and increases production flexibility. In addition, the fact that pattern coating involves applying the adhesive in direct, actual shapes permits more efficient use of materials, especially when the sizes and shapes of the figure portions  12  vary greatly. Moreover, registration of the printing to adhesive application to die-cutting steps is greatly improved since all steps are accomplished continuously and simultaneously. Thus far, Method 2 has been found superior to Method 1 in terms of cost and quality. 
     Method 3 
     The third method according to the present invention is generally a seven-step method that combines several production techniques used in different disciplines of the graphic arts. Unlike the first two flexographic methods described above, the Method 3 entails offset lithographic printing of images  66  on a cellulosic based material such as paper rather than on a clear polymeric based material. In addition, the third method operates on sheets of materials rather than the rolls of the flexographic methods. 
     Referring to FIG. 15, individual sheets  100 , preferably constructed of paper, are drawn from a batch  102  and fed through offset lithographic printing apparatus  104 , which comprises one or more print decks  106 , 108 , 110 , 112 . Each print deck  106 , 108 , 110 , 112  applies a differently colored ink to a print or back side  114  of each sheet  100 . Each printed sheet  116  has various images  66  arranged in a manner similar to the images produced in Method 2, as shown in FIG.  16 . In the present method, however, it is not necessary to print reversed or mirrored images. The printed sheets  116  are collected into a batch  117  and transferred to a die pattern station  118 , which consists essentially of an additional offset lithographic print deck  120  and is shown in FIG.  17 . The additional print deck  120  prints a die pattern  122 , preferably in black ink, on the front side  124  of each sheet  116  to produce patterned sheets  126 . As shown in FIG. 18, the die patterns  122  are in register with the corresponding images  66  printed on the back side  114  and are used as a die-cutting guide for the die-cutting equipment described below. 
     The patterned sheets  126  are collected and transferred to a laminating machine  128 , shown in FIG.  19 . The laminating machine  128  applies a clear, rigid laminate layer  129  to the back side  114  of each sheet  126  to form a laminated sheet  130 . The laminated sheets  130  are collected and transferred to an adhesive application station  132  of the type typically used in silk screening operations, shown in FIG. 20. A pressure sensitive adhesive is applied in a predetermined pattern to the laminate layer  129  on the back side  114  of each laminated sheet  130 . The laminated sheets  130  are then collected and transferred to liner application apparatus  134  shown in FIG. 21, also of the type typically used in silk screening operations. The liner application apparatus  134  further laminates the sheets  130  by applying a releasable liner material  20  to the laminate layer  129 . FIG. 22 shows the front side  124  of one of the laminated sheets  130  with the releasable liner material  20  acting as a substrate. Reference numeral “ 92 ” designates the locations where the adhesive coatings  86  have been applied adjacent corresponding images  66  on the back side  114 . 
     Once the laminated sheets  130  have each been provided with the releasable liner material  20 , the sheets  130  are transferred to a die-cutting station  136 , shown in FIG. 23, where the sheets  130  are die-cut and perforated in a manner analogous to the finishing operations described above in relation to Methods 1 and 2. Again, the die or dies used may be nicked. Also, a scoring step may be elected in place of perforation. As shown in FIG. 24, the sheets  130  are then run through sheet cutting apparatus  138  such as a flat cutter and trimmed or cut to a finished size. Preferably, a finished sheet  140  will have a length of 7.25″ and a width of 4″. FIG. 25 shows the front side  124  of the finished sheet  140 . The die-cutting operation results in an outline  14  cut about each printed image  66  and corresponding adhesive coating  86  to define figure and base portions  12 , 16 . The die-cutting operation also creates a perforated line  18  between each figure and base portion  12 , 16 . As in the case of Methods 1 and 2, the resulting set of varied stickers  10  on each sheet  140  are preferably thematically related. 
     FIG. 26 diagrammatically summarizes the construction of the finished sticker  10  with its several layers shown in exploded view. As described, the sticker  10  is based on the original sheet  100  which is preferably a paper layer. The paper layer  100  has a black die pattern  122  printed on its front side  124  and a series of differently colored ink applications  88  on its back side  114  which result in the figure or graphic image  66 . The paper layer  100  is laminated with a clear, rigid laminate layer  129  on the printed back side  114 , and a pressure sensitive adhesive coating  86  exists on the base portion  16  of the laminate layer  129 . The finished sticker  10  is in releasable contact with the liner material  20  on the side of the laminate layer  129  carrying the adhesive coating  86 . 
     It will be understood that the present method may be modified such that each sheet  130 , before it is run through the cutting apparatus  138 , contains a plurality of sets or groups of thematically related stickers  10 . For example, each sheet  130  may contain four groups having the same theme or four groups having different themes. In such a case, the cutting apparatus  138  would be used to divide each sheet  130  into smaller individual sheets that each contain only one group of stickers  10 . 
     It should be noted that because all of the needed operations must be accomplished individually and off-line, Method 3 is much more costly than the Methods 1 and 2, especially where large-quantity production runs are contemplated. While reproduction by the offset lithography process in Method 3 is superior as compared the flexographic printing methods of Methods 1 and 2, in many situations the improved print quality will not justify the significant cost difference. At present, it is believed that Method 3 is viable cost-wise only for low-quantity production runs. Thus, Method 2 is considered overall to be the best method described herein for the efficient production of standable stickers  10  of commercially acceptable quality. 
     It will be understood that application of the stickers  10  produced by the above-described methods is not limited to the coated display surface  24 . Alternatively, where repositionability or rearrangement of the stickers  10  is not contemplated, the stickers  10  described herein may be permanently adhered to surfaces such as paper stationery. 
     It will also be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.