Method and apparatus for forming a threaded neck on a metallic bottle

Abstract

An apparatus and method of making and applying threaded twist-off neck finishes for metal containers is provided. More specifically, the present invention relations to apparatus and methods used to form metallic bottles with threaded necks adapted to receive selectively removable threaded closures. The threaded neck may be formed by interconnecting a threaded outsert to a metallic bottle. Alternatively, the threaded neck may be formed as an integral portion of the neck of the bottle.

Claims

1. A method for forming a threaded neck on a neck portion of a metallic bottle, comprising: providing a metallic bottle comprising a bottom dome portion, a body portion, said neck portion extending upwardly from said body portion, and an opening positioned on an uppermost portion of said neck portion, wherein said neck portion is adapted to receive a plastic threaded outsert; die necking an uppermost portion of said neck portion to reduce a diameter of said uppermost portion; forming a retention bead on said reduced diameter neck portion which has an outer diameter that is larger than said reduced diameter neck portion, said retention bead having an upwardly oriented shoulder on an uppermost portion of said retention bead; forming said plastic threaded outsert, having a hollow cylindrical body portion and threads extending from an exterior surface, wherein said outer diameter of said retention bead is greater than an outer diameter of said exterior surface of said plastic threaded outsert; placing said plastic threaded outsert over said reduced diameter neck portion of said metallic bottle such that a lowermost portion of said plastic threaded outsert is proximate to said upwardly oriented shoulder, wherein said upwardly oriented shoulder engages substantially the entire lowermost portion of said plastic threaded outsert to prevent said plastic threaded outsert from sliding in a downward direction on said neck portion of said metallic bottle; and outwardly bending said reduced diameter neck portion above said plastic threaded outsert to form a flange with a distal end extending outwardly and away from said neck portion to form a substantially horizontally oriented shoulder adapted to engage an uppermost portion of said plastic threaded outsert, said flange having an outer diameter that is less than said outer diameter of said retention bead, wherein said plastic threaded outsert is interconnected to said neck portion of said metallic bottle, and wherein said threaded neck is adapted to receive a twist-off closure.

2. The method of claim 1, wherein a distance between crests of said threads formed on said plastic threaded outsert is approximately 0.093 inches such that said threads are adapted to receive the twist-off closure with an interior diameter of less than about 1.10 inches.

3. The method of claim 1, further comprising forming anti-rotation beads on an exterior surface portion of said neck portion of said metallic bottle before said plastic threaded outsert is placed over said neck portion, said anti-rotation beads increasing a coefficient of friction between said exterior surface portion and said plastic threaded outsert.

4. The method of claim 1, wherein said hollow cylindrical body portion of said plastic threaded outsert has an interior diameter of less than about 0.95 inches such that said threaded neck of said metallic bottle is adapted to receive said twist-off closure having an interior diameter of between about 1.0 inches and about 1.10 inches.

5. The method of claim 1, wherein said outer diameter of said flange is less than an outer diameter of said exterior surface of said plastic threaded outsert such that the plastic threaded outsert forms a substantially smooth transition from said flange to said exterior surface.

6. The method of claim 1, wherein said twist-off closure is a roll on pilfer proof closure.

7. The method of claim 1, wherein said threads formed on said plastic threaded outsert have a depth of between approximately 0.15 inches and approximately 0.023 inches.

8. The method of claim 7, wherein said plastic threaded outsert has a height between approximately 0.30 inches and approximately 0.60 inches.

9. The method of claim 8, wherein said hollow cylindrical body of said plastic threaded outsert has a thickness between about 0.050 inches and about 0.150 inches.

10. The method of claim 9, wherein said outer diameter of said exterior surface of said plastic threaded outsert is between approximately 0.998 inches and approximately 1.023inches such that said threaded neck is adapted to receive the twist-off closure having an interior diameter of less than about 1.10 inches.

11. The method of claim 1, wherein said outer diameter of said retention bead is about equal to an outer diameter of said threads formed on said plastic threaded outsert.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the Summary of the Invention given above and the Detailed Description of the drawings given below, serve to explain the principles of these embodiments. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. Additionally, it should be understood that the drawings are not necessarily to scale.

(2) FIG. 1 is a front elevation view of a metallic bottle with a threaded outsert interconnected on a neck portion according to one embodiment of the present invention;

(3) FIG. 2 is a fragmented front elevation view of a neck of a metallic bottle according to one embodiment of the present invention prior to interconnection of a threaded outsert to the neck;

(4) FIG. 3A is a front elevation view of a threaded outsert according to one embodiment of the present invention;

(5) FIG. 3B is a cross-sectional front elevation view of the threaded outsert of FIG. 3A taken along line 3B;

(6) FIG. 4A is a fragmented front elevation view of the threaded outsert of FIG. 3A placed on the neck of the metallic bottle of FIG. 2;

(7) FIG. 4B is a fragmented, cross-sectional front elevation view of the threaded outsert of FIG. 3A interconnected to the neck of the metallic bottle of FIG. 2;

(8) FIG. 5A is a front elevation view of a metallic bottle with a threaded neck portion formed according to certain embodiments of the present invention;

(9) FIG. 5B is a fragmented, cross-sectional front elevation view of the curled neck of the metallic bottle of FIG. 5A before formation of the threaded neck portion;

(10) FIG. 6 illustrates a method of roll forming threads into the curled neck of the metallic bottle of FIG. 5B according to one embodiment of the present invention;

(11) FIG. 7 illustrates a method of cutting threads into the curled neck of the metallic bottle of FIG. 5B according to one embodiment of the present invention; and

(12) FIG. 8 illustrates a method of compression forming threads into the curled neck of the metallic bottle of FIG. 5B according to one embodiment of the present invention.

(13) A component list of the various components shown in drawings is provided herein:

(14) TABLE-US-00001 Number Component 4 metallic bottle 6 threaded outsert 8 body 12 bottom 16 sidewall 20 neck 24 opening 28 first exterior diameter 32 retention bead 36 second exterior diameter 40 neck exterior surface 42 cylindrical body of outsert 44 interior diameter of outsert 46 exterior diameter of outsert 47 exterior thread diameter 48 outsert height 52 outsert thickness 56 threads 60 helical ridges 64 exterior surface of outsert 65 first radius 66 second radius 67 thread flat portion 68 thread depth 69 thread pitch 72 interior surface of outsert 76 curl 80 uppermost surface 82 distance to start of first thread 84 distance to bottom of thread 104 metallic bottle 108 curl 110 vertical axis of bottle 112 vertical roller 113 rotation 114 vertical roller surface 116 axis 118 exterior roller 119 exterior roller surface 120 lateral movement 122 vertical movement 124 cylindrical cutter 128 cylindrical mandrel 130 side molds 132 contact surface

DETAILED DESCRIPTION

(15) Various embodiments of the present invention are described herein and as depicted in the drawings. The present invention has significant benefits across a broad spectrum of endeavors. It is the Applicants' intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the invention.

(16) Referring now to FIG. 1, a metallic bottle 4 is illustrated with a threaded outsert 6 according to one embodiment of the present invention. The metallic bottle 4 and threaded outsert 6 may be formed separately and the threaded outsert 6 interconnected to the metallic bottle 4 as described below. Alternatively, the threads may be formed as an integral portion of the neck of the metallic bottle, thus eliminating the need for an outsert.

(17) Manners of forming metallic bottles 4 are generally known in the art. The metallic bottle is generally formed from a sheet of aluminum or steel in a draw and wall ironing (DWI) process or from a slug of aluminum or steel in an impact extrusion process. The metallic bottle 4 has a generally cylindrical body 8. Optionally, the metal body 8 is coated on all interior and exterior surfaces and the coatings cured to protect the metal of the body 8 from tooling contact, corrosion, and/or to protect the contents of the metallic bottle 4. The metal body 8 has a bottom dome portion 12. The metal body also has a sidewall portion 16, a neck portion 20 extending upwardly from the sidewall portion 16, and an opening 24 positioned on an uppermost portion of the neck 20.

(18) Referring now to FIG. 2, a fragmented front elevation view of the neck 20 of the metallic bottle 4 is illustrated before interconnection of the threaded outsert 6 thereto. A series of die necking operations have been performed on the body 8 to reduce the diameter of the body 8 to form the neck 20 with a predetermined shape and diameter. Methods and apparatus used in necking metal containers are generally known in the art as disclosed in U.S. Pat. Nos. 4,403,493, 4,693,108, 4,732,027, 5,138,858, 5,448,903, 5,469,729, 5,713,235, 5,778,723, and 7,140,223 which are each incorporated herein by reference in their entirety. The uppermost portion of the neck 20 has a first predetermined exterior diameter 28. During the die necking operations, an expanded ring or retention bead 32 is formed with a second predetermined exterior diameter 36. Optionally, the exterior diameter 36 may match the diameter of the neck 20. The diameter 36 of the retention bead 32 is larger than the diameter 28 of the uppermost portion of the neck 20. The retention bead 32 retains the threaded outsert 6 in a predetermined position on the neck 20 to prevent the threaded outsert 6 from sliding. Optionally, anti-rotation features may be formed on an exterior surface 40 of the neck 20 to prevent inadvertent rotation or movement of the threaded outsert 6 when twisting a closure (not illustrated) threadably interconnected to the metallic bottle 4. In one embodiment, the anti-rotation features may be bumps, beads, or ridges, combinations thereof, or any other shape selected to increase the coefficient of friction between the exterior surface 40 of the neck 20 and an interior surface of the threaded outsert 6. In another embodiment, the anti-rotation feature is an adhesive or sealant applied to the exterior surface 40 of the neck 20 before interconnecting the threaded outsert 6 to the neck 20.

(19) Referring now to FIG. 3A, the threaded outsert 6 is illustrated prior to interconnection to the metallic bottle 4. The threaded outsert 6 may be formed of metal, injection molded from a plastic material, or made of any other material known to those skilled in the art. The threaded outsert 6 is generally comprised of a hollow cylindrical body 42. Threads 56 are integrally formed on an exterior surface portion of the body 42 of the threaded outsert 6. The threaded outsert 6 has an interior diameter 44 large enough for the threaded outsert 6 to be placed on the neck 20 of the metallic bottle 4. As may be appreciated by one of skill in the art, the threaded outsert 6 has any interior diameter 44 larger than the first exterior diameter 28 of the neck 20, but less than the exterior diameter 36 of the retention bead 32. In one embodiment, the minimum interior diameter 44 of the threaded outsert 6 is less than approximately 0.95 inches, but the dimension is directly related to the size of the bottle neck, which can vary significantly based on the application. In one embodiment, the threaded outsert 6 has an exterior diameter 46 between approximately 0.998 inches and approximately 1.023 inches. In a preferred embodiment, the exterior diameter 46 of the threaded outsert 6 is approximately 1.010 inches. In one embodiment, an exterior diameter 47 of the threads 56 of the threaded outsert 6 is between approximately 1.038 inches and approximately 1.063 inches. In a preferred embodiment, the exterior diameter 47 of the threads 56 is approximately 1.05 inches.

(20) FIG. 3B is a cross-sectional front elevation view of the threaded outsert 6 taken along line 3B-3B of FIG. 3A. In one embodiment, the threaded outsert 6 has a height 48 of between approximately 0.30 inches and approximately 0.60 inches. In another embodiment, a thickness 52 of the threaded outsert 6 is between approximately 0.050 inches and approximately 0.150 inches.

(21) Helical ridges 60 form threads 56 on an exterior surface 64 of the threaded outsert 6. The threads 56 have a size, shape, alignment, and geometry similar to threads of glass containers which are generally known in the art as disclosed in drawings produced and distributed by the Glass Packaging Institute (GPI), including GPI drawing number 5457 for glass finish number 545 which is incorporated herein in its entirety by reference. In one embodiment, the threads 56 of the threaded outsert 6 have the dimension, shape, geometry, and alignment of threads described in GPI drawing number 5457. In another embodiment, threads 56 are adapted to interconnect with a ROPP closure with a diameter between approximately 0.90 inches and approximately 1.10 inches. In still another embodiment, the threads 56 have a first radius of curvature 65 of no more than approximately 0.020 inches. In yet another embodiment, the threads 56 have a second radius of curvature 66 of approximately 0.016 inches. In still another embodiment, the threads 56 may have an optional flat portion 67 with a maximum width of approximately 0.007 inches. In yet another embodiment, the threads 56 have a depth 68 of between approximately 0.15 inches and approximately 0.023 inches. In a preferred embodiment, the depth 68 of the threads 56 is approximately 0.20 inches. In still another embodiment, the threads 56 start approximately 90° apart and have four leads, each lead generally having 2.7 turns per inch, a thread lead of approximately 0.370 inches, a cutter diameter of approximately 0.500 inches, a helix angle of approximately 6° 31′, and a minimum thread travel of approximately 108°. In yet another embodiment, the threads 56 have a pitch 69, or distance from the crest of one thread to the next crest, of approximately 0.093 inches. Although various dimensions have been provided to describe one exemplary embodiment of the threaded outsert 6 and the threads 56, it is expressly contemplated that dimensions of the threaded outsert 6 and the placement, dimensions, spacing, and geometry of the threads 56 may be varied and still comport with the scope and spirit of the present invention.

(22) Optionally, anti-rotation features may be formed on an interior surface 72 of the threaded outsert 6 to prevent inadvertent rotation or movement of the threaded outsert 6 after interconnecting the threaded outsert 6 to the metallic bottle 4. For example, the anti-rotation features may prevent inadvertent rotation or movement of the threaded outsert 6 when a closure (not illustrated) is twisted to open the metallic bottle 4. In one embodiment, the anti-rotation features may be shapes such as bumps, beads, groves, protrusions, or ridges, or combinations thereof, or any other shape selected to increase the coefficient of friction between the exterior surface 40 of the neck 20 and the interior surface 72 of the threaded outsert 6. In another embodiment, the anti-rotation feature may be an adhesive or sealant applied to the interior surface of the threaded outsert 72 or to the exterior surface 40 of the neck 20 before interconnection of the threaded outsert 6 to the neck 20.

(23) After forming the metallic bottle 4 and the threaded outsert 6, the outsert 6 is placed over the neck 20 as illustrated in FIG. 4A. The threaded outsert 6 is retained in a predetermined position by the retention bead 32. Referring now to FIG. 4B, a curling operation expands the neck 20 above the threaded outsert 6 to form a curl 76 to interconnect the threaded outsert 6 to the metallic bottle 4. The curl 76 is closed above the threaded outsert 6 to prevent unintended or inadvertent movement or rotation of the threaded outsert 6. In one embodiment, a radius of curvature of the curl 76 is between approximately 0.031 inches and approximately 0.063 inches. Sealing surfaces are formed on an uppermost surface 80 of the metallic bottle 4. The sealing surfaces are adapted to be rigid and dimensionally consistent to contact a liner of a closure to seal the metallic bottle 4 and prevent leakage of liquid or gas. The uppermost surface 80 is substantially parallel to the bottom 12 of the metallic bottle 4. In one embodiment, an interior surface portion 80A of the uppermost surface 80 has a maximum radius of curvature of approximately 0.031 inches. In another embodiment, a maximum distance 82 from the uppermost surface 80 of the metallic bottle 4 to the start of the first full thread 56A is approximately 0.088 inches. When the threads 56 are formed without the optional flat portion 67 (illustrated in FIG. 3B), the maximum distance 82 is approximately 0.095 inches. In still another embodiment, a minimum distance 84 of approximately 0.234 inches separates the uppermost surface 80 of the metallic bottle 4 from a bottom swing of the second radius 66 of a thread 56B at the lowest point at the end of the thread 56B. In yet another embodiment, the sealing surfaces of the upper surface 80 of the metallic bottle 4 have the dimensions and geometry described in GPI drawing number 5457.

(24) Referring now to FIG. 5A, a metallic bottle 104 is depicted with threads 56 on a neck portion 20 formed by rolling, cutting, or compression according to various embodiments of the present invention. The metallic bottle 104 may be formed, coated, and cured as described above in conjunction with FIG. 1. The metallic bottle has a metal body 8, a bottom dome portion 12, a sidewall portion 16, a neck portion 20 extending upwardly from the sidewall portion 16, and an opening 24 positioned on an uppermost portion 80 of the neck 20. The threads 56 and the uppermost portion 80 of the metallic bottle 104 have the dimensions and geometry described above in the text accompanying FIGS. 3A, 3B, and 4B. In one embodiment, the threads 56 and uppermost portion 80 of the metallic bottle 104 have the dimensions and geometry described in GPI drawing number 5457. However, as appreciated by one skilled in the art, any variety of sizes and dimensions can be utilized and practiced with the present invention depending on the required size of the bottle.

(25) Referring now to FIG. 5B, a cross-sectional front elevation of the neck 20 of the metallic bottle 104 is illustrated before threads have been formed thereon. The metallic bottle 104 has been necked to a predetermined diameter. A curl 108 of a predetermined size and thickness is formed on the neck 20. The curl 108 may optionally be formed of multiple rolls of the metal of the neck 20.

(26) A method and apparatus of roll forming threads 56 on the metallic bottle 104 according to one embodiment of the present invention is illustrated in FIG. 6. The metallic bottle 104 is mounted in a mandrel (not illustrated) and the metallic bottle 104 is spun about a substantially vertical axis 110 extending through the center of the metallic bottle 104. A vertical roller 112 is inserted into the opening 24 of the spinning metallic bottle 104. In the illustrated embodiment, the vertical roller 112 has a contoured exterior surface 114; however, it is contemplated that the exterior surface 114 of the vertical roller 112 may be smooth or contoured. The vertical roller 112 rotates in a first direction 113 about an axis 116 which is substantially parallel to the axis 110 of the metallic bottle 104. An exterior roller 118 with a contoured exterior surface 119 of a predetermined shape is positioned on the exterior of the metallic bottle 104. The exterior roller 118 rotates in a second direction about a vertical axis substantially parallel to axis 110. The second direction is opposite to the first direction. Both the vertical roller 112 and the exterior roller 118 can move laterally as indicated by horizontal arrows 120 and/or vertically as indicated by vertical arrows 122. Although FIG. 6 illustrates the vertical roller 112 rotating in a counter-clockwise direction and the exterior roller 118 rotating in a clockwise direction, it is expressly contemplated that vertical roller 112 can rotate in the clockwise direction and the exterior roller 118 can rotate in the counter-clockwise direction and still comport with the scope and spirit of the present invention.

(27) The exterior surface 114 of the vertical roller 112 is moved into contact with an interior surface of the neck 20 of the metallic bottle 104. The contoured exterior surface 119 of the exterior roller 118 is moved into contact with an exterior surface portion of the curl 108 (illustrated in FIG. 5B) of the neck 20. The surfaces 114, 119 of the vertical roller 112 and the exterior roller 118 apply a compressive force therebetween to the curl 108 of the metallic bottle 104 to form threads 56 of a predetermined size, shape, and geometry in the neck portion 20 of the metallic bottle 104. During the threading, both the vertical and exterior rollers 112, 118 may move laterally and vertically and the vertical roller 112 provides support to the neck 20 of the metallic bottle 104. The surface 114 of the vertical roller 112 may optionally form a predetermined shape or profile on the interior surface of the neck 20 of the metallic bottle 104. In one embodiment, the metallic bottle 104 is mounted in a mandrel, but the bottle 104 remains stationary while the vertical and exterior rollers 112, 118 rotate about the bottle 104 during the threading.

(28) A method and apparatus of cut forming threads 56 on the metallic bottle 104 according to another embodiment of the present invention is illustrated in FIG. 7. The metallic bottle 104 is positioned in a mandrel (not illustrated) and spun about the substantially vertical axis 110 extending through the metallic bottle 104. At least one cylindrical cutter 124 rotates 113 about the axis 116 substantially parallel to axis 110 and moves both laterally 120 and vertically 122. Alternatively, the cylindrical cutter 124 moves only in a lateral direction 120. Cutting surfaces of the cylindrical cutter 124 are moved into cutting contact with the exterior surface of the curl 108 (illustrated in FIG. 5B) to cut threads into the neck portion 20 of the metallic bottle 104. Optionally, in one embodiment, a mandrel may hold the bottle 104 stationary while the cylindrical cutter 124 moves around the bottle 104 to cut threads into the neck portion of the bottle 104. In another embodiment, a mandrel 128 (illustrated in FIG. 8) may optionally be inserted into the opening 24 of the bottle 104 to hold the bottle and provide support to the neck 20 of the bottle 104 while the cylindrical cutter 124 cuts the threads 56 into the neck 20. In yet another embodiment, one or more of the cutting surfaces of the cylindrical cutter have a cutting profile that is different than one or more other cutting surfaces of the cylindrical cutter. In still another embodiment, two cylindrical cutters are used to cut the threads in the exterior surface of the curl.

(29) Referring now to FIG. 8, a method and apparatus of compression forming threads 56 on the metallic bottle 104 is illustrated. The metallic bottle 104 is positioned in a mandrel (not illustrated) that provides support to the metallic bottle. A cylindrical mandrel 128 that moves vertically 122 is inserted into the opening 24 of the metallic bottle 104 in force receiving contact with an interior surface of the neck 20. Optionally, in one embodiment, the cylindrical mandrel 128 may seal the interior of the metallic bottle 104 and introduce a gas, such as air, into the interior of the metallic bottle 104 to pressurize the interior and increase the rigidity of the metallic bottle 104. Two or more side molds 130 are positioned around the exterior surface of the curl 108 (illustrated in FIG. 5B) of the metallic bottle 104. The side molds 130 have contact surfaces 132 with a predetermined shape adapted to form threads 56 in the curl 108 of the metallic bottle 104. The contact surfaces 132 of each of the two or more side molds 130 can have a different predetermined shape. The side molds 130 close around the neck 20 and create a compressive force between the mandrel 128 and side molds 130 to compress the curl 108 and the neck 20 and form the threads 56 in the neck 20 of the metallic bottle 104.

(30) Threaded metallic bottles 4, 104 of the present invention are adapted to be sealed with a threaded closure (not illustrated). The closure may be formed of steel, plastic, or any other material known to those of skill in the art. The closure can be of any size or geometry known in the industry, such as closures currently used to seal glass bottles of all sizes. After the threaded metallic bottle 4, 104 is filled with a selected product, the closure is placed over the opening 24 and threadably engaged with the threads 56 by methods known in the art to seal the product into the metallic bottle 4, 104 without leakage of liquid or gas. One or more interior surfaces of the closure contact and apply a sealing force to the sealing surfaces formed on the uppermost surface 80 of the metallic bottles 4, 104. The closure may optionally have an elastomeric disk that contacts and is compressed between the uppermost surface 80 of the metallic bottles 4, 104 and the closure. In one embodiment, a sealant may be applied to the uppermost surface 80 or to the interior surface of the closure before placing the closure over the opening 24. To open a sealed metallic bottle 4, 104, the consumer rotates the closure causing the helical ridges 60 of the threads 56 to drive the closure loose and off of the metallic bottle 4, 104.

(31) The present invention has many benefits compared to prior art metal bottles. The threaded neck portion of a metallic bottle of the present invention allows the metallic bottle to be sealed with closures of known sizes. Closures used to seal metallic bottles of the present invention may be removed without the use of a separate tool. Once opened, the metallic bottles of the present invention may be selectively resealed by threading a closure that has been removed from the metallic bottle back onto the bottle.

(32) The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the invention, the practical application, and to enable those of ordinary skill in the art to understand the invention.

(33) While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. It is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims.