Strong, externally smooth structures

FIELD OF INVENTION

This invention relates to components for easy construction of structures, and more particularly to tubular frame components for easy construction of strong, externally smooth structures.

BACKGROUND OF INVENTION

It has long been known that combinations of tubes and connectors can be used to quickly create framework structures such as jungle-gyms and tents. By connecting tubes at their ends, the frameworks for geodesic domes, furniture and display cases can be created.

In a typical system, that of U.S. Pat. No. 5,169,258 (issued to Raynak), the fittings have cylindrical pins protruding from a semi-spherical body. PVC pipes are plugged onto the pins and so used to form even large structures such as the framework of a house. Other similar patents (U.S. Pat. No. 4,273,462 to Fukuchi; U.S. Pat. No. 4,242,969 to Checkwood et al.; U.S. Pat. No. 4,187,649 to Chaffee; U.S. Pat. No. 3,074,203 to Paksy) use various types of connectors to assemble pipes into larger structures such as display cases and coffee tables.

Other patents have used the same general technique with tubes having a square cross section: U.S. Pat. No. 5,820,289 to Kern et al.; U.S. Pat. No. 5,451,115 to Sayres; U.S. Pat. No. 4,368,998 to Pestoor; and U.S. Pat. No. 3,736,035 to Brown et al. There are certain advantages all such systems possess.

All the references listed above combine flexibility of design with ease of construction. By altering the arrangement of connectors and tubes new structures can be designed with great ease. Construction is also very easy, as the standardized connectors (also called fittings, joints or corners) and tubes (also called pipes or frame members) can be manufactured with great economy and put together quickly, with few or no special tools and by personnel having little experience or training. If the structure needs to be later modified, most such designs allow for easy disassembly and reassembly in a new configuration.

Such structures also tend to have certain general weaknesses. The completed structure is not a shell or panel type of structure and therefore stress, strain, and torsion, are all applied directly and fully at the couplings between fittings and pipes. Repeated cycles of use, or repeated applications of force to the completed structure, quickly deform the couplings and the structure tends to fall apart shortly.

Most of the references cited above do not refer to paneling. Those that do refer to paneling or shelves (for example, Brown and Kern) teach the panel or shelf as something requiring support from the tubular cross members. None of the references offer means for reducing the forces induced in the couplings, and none offer the panels as structural support for the framework. Finally, none of the references disclose structure allowing a flush, smooth tangential connection of paneling and circular section framework. In each case, paneling is taught as being radial to the tubular framework, not tangential.

One attempt to make the panels bear a structural burden can be seen in U.S. Pat. No. 5,647,650, issued Jul. 15, 1997 to Daugherty et al. In this case, the tubular support structures (there are no cross beams) have wide flanges which grip the end of a wall, thus helping to distribute imposed forces. The panels may be angled, rather than directly radial, but the wide flanges necessarily protrude from the completed structure. More importantly, that system is not actually modular, as it lacks fittings or connectors to connect the tubes, thus flexible design and assembly in to a wide variety of structures is not possible. The modular tubes of Daugherty ('650) are vertical members only, held in place on a base plate which may form the bottom of a wheeled cabinet. A complete framework, as such, is not present, and as with the above references, no structure is disclosed allowing a smooth, flush tangential connection of the paneling and the framework.

SUMMARY AND OBJECTS OF INVENTION

The invention consists of several components which interlock to form a strong, externally smooth structure. Tubes (also called pipes or frame members) are connected at their ends by fittings (also called joints or corners). The fittings have faces which are symmetrical in external form and size the external surface of the tubes, thus providing flush, smooth joints. The invention also has a panel which attaches to the framework of tubes and fittings. The panel connects to the side of the framework, on the plane defined by tangents of the tubes, rather than in the plane defined by the axes of the tubes, or some plane in between.

In order to provide a smooth, flush fit between the panel and the framework, a recess is provided in the tubes and fittings to accept the panel. The recess runs in a continuous groove along the length of a tube, transfers along the matching faces of the fitting, and then along the length of a second tube matched to the other end of the fitting. The recesses may engage the entire periphery of the panels, by traversing from tube to fitting around the entire periphery of the panel. They may also be discontinuous.

The recess forms a partial chordal section of the tubes if one were to view a circular cross section of a tube: one surface of the panel fits chordally into the tube's surface while an edge of the panel is substantially radial to the tube. Thus the recess has a first surface which is parallel to the panel's exterior surface, which will be referred to herein as the bottom of the recess. The recess also has one surface which is substantially normal to the panel's exterior surface, which will be referred to herein as the peripheral wall of the recess. The thickness of the panel is equal in depth to the recess as measured from the exterior surface of the tube to the bottom along the peripheral wall. The panel's exterior surface will thereby join smoothly to the tube's exterior surface, and to the exterior surfaces of the fittings, without any step, gap, or discontinuity.

The fasteners used to hold the various components together may be disposed within the completed structure, resulting in an entirely smooth exterior. This requires that three different properties of the edge of the panel be shaped to exactly mate with the recess. First, the edge outline is the shape of the panel in two dimensions not including thickness. The edge outline may be a perfect square, a square with rounded corners, or other shapes. Also, the panel may not be wholly planar, instead being contoured in three dimensions, for example as a nose-cone or other bulbous shape.

The second property, the edge thickness, is generally equal to the depth of the recess. However, edge thickness may be less than the depth of the recess if, for example, the peripheral wall is situated at an angle to the radius of the tube, rather than being exactly radial. The balance of the panel is also usually, but not necessarily, the same thickness as the edge thickness.

Finally, the edge cross section is viewed in the plane normal to the surface of the panel and perpendicular to the axis of the tube. The shape of the edge cross section may either vary or be constant around the entire periphery of the panel. In the preferred embodiment, the edge cross section will be complementary to the cross section of the recess in the plane perpendicular to the axis of the tube. The complementary edge cross section and recess cross section provide a snug and continuous contact between the panel edge and the recess. The three different properties of the edge of the panel thereby create the three dimensional shape exactly matching the space defined by the recess.

Smooth exteriors are beneficial in applications in which streamlining is important, such as trailers. Smooth exteriors are also useful any time projections on a structure would be disadvantageous, for example when projections might catch on external machinery. The form is also eye-pleasing.

The structure's interior will not be smooth or flush; because the panels are tangential to the exterior of the tubes, a cavity between the panel and the fittings and tubes of the framework is formed in the interior. There may also be visible on the inside of the structure, apparatus for securing the panels to the framework. For example a linear bead of welded metal may be used to secure the panel to the tubes and fittings. Stud/bolt and bracket combinations may also be used. This less eye-pleasing interior can be easily modified by making a structure with panels tangential to both sides of the framework. This embodiment not only allows both the structure's interior and exterior to be smooth, but also greatly strengthens the structure. The interior of the assembled structure should not be confused with the “tube interior,” the interior of the tube components.

More importantly, the panel is a planar load bearing member. Most fitting and tube structures must absorb all imposed forces at the connection of cross pieces and corner, thereby allowing small forces to generate large torques. In contrast, the present invention takes advantage of the panel to provide a distributed load bearing structure: a monocoque shell. A load imposed on a tube at the top of the structure will not be primarily transmitted to the fittings at the end of the tube, but rather largely to the panel edge by the opposing peripheral wall of the tube's recess. The panel will in turn transmit the force to the recess of the tube on its far side, and so on until the force is absorbed.

It is therefore one object of the invention to provide an improved structural system allowing use of structural panels with easy assembly.

It is another object of the invention to provide a tube and fitting framework which allows speedy assembly, yet which reduces the forces induced in the couplings between tubes and fittings.

It is another object of the invention to provide a structural system which allows easy assembly of a strong monocoque structure.

It is another object of the invention to provide a structural system allowing easy assembly of strong structures able to withstand numerous cycles of use.

It is another object of the invention to provide a structural system allowing use of structural panels yet allowing easy manufacture of the system components.

It is yet another object of the invention to provide a structural system allowing a smooth, flush joint between panels and elements of a tubular framework.

It is yet another object of the invention to provide a structural system allowing easy assembly of strong, streamlined structures.

It is yet another object of the invention of provide a structural system allowing a tangential joint between panels and elements of a tubular framework.

It is yet another object of the invention to provide a method of constructing a tube and fitting structure having structural panels and a smooth exterior.

It is yet another object of the invention to provide a structural system allowing construction of a structure which has no projecting flanges, fittings, or fasteners.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1

a

is a cross sectional view of a tube, in a plane perpendicular to its axis, according to the preferred embodiment of the invention.

FIG. 1

b

is a perspective view of a tube according to the preferred embodiment of the invention.

FIG. 1

c

is a perspective view of a tube mated to a panel according to the to preferred embodiment of the invention.

FIG. 2

a

is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a first alternative embodiment of the invention.

FIG. 2

b

is a perspective view of a tube according to the preferred embodiment of the invention.

FIG. 3

a

is a perspective view of an elbow-type fitting according to the preferred embodiment of the invention.

FIG. 3

b

is a perspective view of a mated fitting and tube according to the preferred embodiment of the invention.

FIG. 4

is a perspective view of a T-type fitting according to the preferred embodiment of the invention.

FIG. 5

a

is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a second alternative embodiment of the invention.

FIG. 5

b

is a perspective view of a tube according to a second alternative embodiment of the invention.

FIG. 6

a

is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a third alternative embodiment of the invention.

FIG. 6

b

is a perspective view of a tube according to a third alternative embodiment of the invention.

FIG. 7

a

is a cross sectional view of a tube, in a plane perpendicular to the tube axis, according to a fourth alternative embodiment of the invention.

FIG. 7

b

is a perspective view of a tube according to a fourth alternative embodiment of the invention.

FIG. 8

a

is a cross sectional view of a tube mated to a panel, in a plane perpendicular to the tube axis, according to a fifth alternative embodiment of the invention.

FIG. 8

b

is a perspective view of a tube mated to a panel according to a fifth alternative embodiment of the invention.

FIG. 9

a

is a cross sectional view of a tube mated to a panel, in a plane perpendicular to the tube axis, according to a sixth alternative embodiment of the invention.

FIG. 9

b

is a perspective view of a tube mated to a panel according to a sixth alternative embodiment of the invention.

FIG. 10

is a perspective view of a structure constructed with the components and according to the methods of the invention.

DETAILED DESCRIPTION OF DRAWINGS

The invention can be better understood by examination of the attached drawings.

FIG. 1

a

is a cross sectional view of a tube

100

, in a plane perpendicular to its axis, according to the preferred embodiment of the invention.

FIG. 1

b

is a perspective view of a section of the tube

100

. Tube

100

is depicted to be circular, however, other cross sections, such as ellipses, ovals, or polygonal figures are all possible without departing from the essence of the invention. Tube

100

is pictured to be hollow, but it is obvious to use a solid member, or one having more complex internal structure. Tube

100

has an exterior surface

102

which defines the circumference of the tube

100

. Exterior surface

102

is interrupted by peripheral wall

104

which cuts into the tube

100

. Peripheral wall

104

and bottom

106

together define the outline and cross section of recess

108

.

The cross section of tube

100

with recess

108

, in a plane perpendicular to the axis of tube

100

, may be described as the intersection of two partial chords of tube

100

. In this case, neither bottom

106

, nor peripheral wall

104

cut completely across tube

100

from one point on its circumference to another. As the partial chord defined by the peripheral wall

104

is radial, within the cross sectional plane, the recess

108

is only a fraction of the section which would be defined by two radii meeting the circumference of the tube

100

at the same locations as the partial chords defined by bottom

106

and peripheral wall

108

. This section defined by recess

108

will be referenced herein as a partial chordal section.

Note too that bottom

106

necessarily has the geometric property of being parallel to some tangent of the circumference of tube

100

. The points at which a tangent is parallel to a chord on a circular surface are those points which are directly perpendicular to the median of the total chord length. Tangents may be at other points on bodies or surfaces of other shapes. Bottom

106

may have projections, studs, or different depths at different portions of panel recess

108

and thus need not be entirely uni-planar; however, bottom

106

is uni-planar in the preferred embodiment shown.

In the preferred embodiment, peripheral wall

104

is radial to the axis of tube

100

and is located at the median of a chord formed by projecting the partial chord defined by bottom

106

across the tube

100

to the opposite point on the exterior surface

102

of the tube

100

. Thus peripheral wall

104

meets exterior surface

102

at the point on the circumference of tube

100

at which the partial chord defined by bottom

106

is parallel to the tangent to the circumference of the exterior surface

102

of the tube

100

.

The result of this is that a flat body such as a panel

110

in

FIG. 1

c

placed along the length of tube

100

will sit with its edge in recess

108

. Further, if the panel

110

has a thickness equal to the radial depth of recess

108

, measured from the tangent point where peripheral wall

104

meets exterior surface

102

to the bottom

106

or its chordal projection, the exterior surface of the panel

110

will meet exterior surface

102

of tube

100

at a smooth junction. In this preferred embodiment of the invention, the radial depth of recess

108

is equal to the length of height of peripheral wall

104

.

The cross section of

FIG. 1

a

can also be visualized as an end view of the tube

100

. Tube

100

may have one or more ends for connection with other components. Tube

100

may branch and form any one of many complex shapes, for example a “T” having three ends. The end of tube

100

is generally annular in shape, with a notch in the outline corresponding to the recess

108

in the exterior surface

102

.

Panel recess

108

will generally be straight. While panel recess

108

may run the entire length of tube

100

, as in the preferred embodiment, this is not necessary. In one equivalent obvious to those skilled in the art, panel recess

108

may span only a fraction of the length of the tube

100

to seat a flat body of length shorter than that of the tube

100

within recess

108

. Panel recess

108

may also be considered to be an asymmetrical groove on exterior surface

102

.

Tube

100

is only one component of the structural kit of the invention. Such a structural kit could contain any of a wide range and number of components including tube

100

, panels

110

, fittings

300

(see

FIG. 3

a

), and special modifications of these. The structural kit may be organized so as to provide easy assembly of a pre-determined structure, with all tubes

100

, panels

110

, and fittings

300

necessary to the task, as well as fasteners, special parts, and so on. One such kit may be used to make a storage box, a second kit having different components may be used to build a storage shed, and a third kit may be used construct a trailer. Many additional possibilities are obvious.

Tube

100

may be constructed in many ways, and composed of a wide range of materials. Tube

100

may be extruded, machined, milled, rolled, or constructed by any other method. For example, the construction of a square tube out of four strips of material is obvious to those skilled in the art. Recess

108

also may be created as tube

100

is extruded, machined, etc, or, recess

108

may be created after tube

100

is finished, by machining, etching, or other finishing process. Tube

100

may be constructed of any of a wide range of materials, including but not limited to, metal, metal alloys, wood, plastic, rubber, other polymers, composites and so on. Tube

100

may be any length or diameter.

FIG. 2

a

is a cross sectional view of tube

200

, in a plane perpendicular to its axis, according to a first alternative embodiment of the invention.

FIG. 2

b

is a perspective view of tube

200

according to this alternative embodiment. Tube

200

has first recess

202

and second recess

204

. Recess

202

and recess

204

are depicted to be at an angle of 90 degrees to each other, in an orientation allowing flat bodies nestled within them to be perpendicular to each other. This is not necessary—an angular alignment of greater or less than 90 degrees may be desirable for the finished structure.

It is even possible to conceive of structures requiring recess

202

and recess

204

be parallel or co-planar.

The invention may also have components with greater or lesser numbers of panel recesses. One member of the structural kit of the invention may have no panel recesses, another member may have more than two.

FIG. 3

a

is a view of a fitting

300

according to the preferred embodiment of the invention. Fitting

300

has a first connector

304

projecting from a first annular face

306

and a second connector

316

projecting from a second annular face

312

.

FIG. 3

b

is a perspective view of fitting

300

mated with tube

302

wherein second annular face

312

abuts tube end

314

. Annular face

312

and tube

314

are axially aligned. The cross section of annular face

312

, in the plane perpendicular to this axis of alignment, is symmetrical to the cross section, in the same plane, of tube end

314

.

Projecting from fitting

300

into tube

302

is connector

316

, unseen in

FIG. 3

b

. The shape of fitting

300

is semi-cylindrical. Fitting

300

has a smooth exterior resembling several intersecting tubes of the same diameter as tube

302

. When tube

302

is connected to fitting

300

, the joint is smooth, the tubular shape of tube

302

carrying across the joint to fitting

300

. In the preferred embodiment of the invention, connector

304

and connector

316

are cylindrical. Tube

302

has an unseen tubular interior of the same diameter as the connector

316

. Tube

302

fits snugly over the connector

316

, providing a tight mating

Fitting

300

and tube

302

are angularly aligned. Tube

302

has recess

310

. Matching recess

310

, fitting

300

has panel recess

308

. When tube

302

is mated to fitting

300

and recess

308

is properly aligned with recess

310

, the two merge into a single larger recess. The recesses

308

and

310

on fitting

300

and tube

302

, respectively, may be alternately disposed along the exterior of the angle formed by the fitting

300

and tube

302

, creating an interior corner for defining an aperture in a paneled surface, such as a window.

Recess

308

may have a cross section, generally viewed in the plane perpendicular to the axis of the circumference of fitting

300

at any particular point, which varies in order to accommodate a flat surface matching recess

310

to the variable contours of fitting

300

. However, the cross section of recess

308

will match that of recess

310

at annular face

312

. Thereafter, the variations in cross section of recess

308

may change to maintain the desired surface across the contours of fitting

300

to accommodate a panel.

Connector

304

, (which may be referred to as a connector, locator, guide, fastener, or by other terms) may be any of a wide range of mechanisms. In the preferred embodiment, it is a cylindrical body which frictionally engages the interior of tube

302

to provide a secure connection. However, connector

304

may be an adhesive, or a cylindrical body covered with adhesive, or any of the ingenious connectors found in the reference patents cited earlier and incorporated herein, or any of many obvious equivalents, all without departing from the scope of the invention.

Cylindrical connector

304

may be a solid projection from fitting

302

, or it may be detachable. It may be rubber covered, or have circular or spiral flanges around the perimeter, to create a tighter joint or a pressure resistant seal. Connector

304

may also be equipped with a washer or O-ring, having a plan-form identical to annular face

306

.

Fitting

300

is depicted with two annular faces,

306

and

312

, and two connectors,

304

and

316

, of the same size. However fitting

300

may also serve to connect tubes or other components of different diameters or even different cross sectional shapes. In addition, the invention contemplates the creation of structures having a smooth exterior, but the interior may be quite complex. Thus, annular face

306

might be symmetrical to the tube end

314

which mates to it, only in those regions which will be externally visible in the finished product. This is one obvious equivalent embodiment of the invention.

Although not preferred, recesses

308

and

310

, in fitting

300

and tube

302

, respectively, may be disposed such that a panel resting in recesses

308

and

310

is not tangential to the exterior surfaces of the fitting

300

and tube

302

. The exterior surface of a structure in such an embodiment may not be externally smooth. Fitting

300

may be manufactured by any of the methods mentioned earlier in reference to tube

100

, and may be made of any of the same materials. Fittings, tubes and panels need not necessarily all be of the same materials.

FIG. 4

is a perspective view of a T-type fitting

400

. Fitting

400

is designed to accommodate three tubes (not pictured) in a planar array. Thus fitting

400

has three connectors,

402

,

404

, and

406

, and two panel recesses,

408

and

410

. Fitting

400

might also have sufficient connectors and annular faces, in other embodiments, to accommodate almost any number of tubes, in planar or non-planar array. In particular, fitting

400

may have three orthogonal connectors and thus serve as a corner of a three dimensional structure. The corner need not be entirely composed of right angles, it may also include any desired angle, allowing for example streamlining of a trailer or for other reasons of convenience. The fitting

400

may also have more than three couplings.

FIG. 5

a

is a cross sectional view of tube

500

, in a plane perpendicular to its axis, according to a second alternative embodiment of the invention.

FIG. 5

b

is a perspective view of tube

500

according this second embodiment. Tube

500

has exterior surface

502

; peripheral wall

504

, channel

506

, and bottom

508

form recess

510

. In this second embodiment of the invention, the panel (not shown) has at least one protrusion, a tab or flange, along the panel edge which engages channel

506

. The panel is secured within recess

510

by the construct of channel

506

.

FIG. 6

a

is a cross sectional view of tube

600

, in a plane perpendicular to its axis, according to a third alternative embodiment of the invention.

FIG. 6

b

is a perspective view of tube

600

according this third embodiment. Tube

600

has exterior surface

602

; peripheral wall

604

and bottom

606

define recess

608

. In this third alternative embodiment of the invention, peripheral wall

604

is not radial to tube

600

; rather, peripheral wall

604

and bottom

606

meet at an acute angle. Peripheral wall

604

and exterior surface

602

do, however, still meet at the point on exterior surface

602

radially outward from the median point of a chord projected by the bottom

606

. As a result, the panel (not shown) still meets exterior surface

602

at an exact tangent. A complimentary panel has a cross section corresponding to the cross section of panel recess

608

with an acute angle on its edge allowing the panel to mate with and be secured within panel recess

608

.

FIG. 7

a

is a cross sectional view of tube

700

, in a plane perpendicular to its axis, according to a fourth alternative embodiment of the invention.

FIG. 7

b

is a perspective view of tube

700

according this fourth embodiment. Tube

700

has exterior surface

702

; peripheral wall

704

and bottom

706

form recess

708

. Tube

700

may be made of any thickness desired, or may be solid, or may be solid for most of its length but have hollows at each end to receive fitting connectors (not shown).

A panel (not shown) is secured to tube

700

by the action of pins

710

, which interpenetrate both the panel and peripheral wall

704

. Peripheral wall

740

and the panel may have cavities prepared for pins

710

, or the pins

710

may be driven into each, respectively. Pins

710

may be manufactured separately, or as part of tube

700

, or as part of the panel. Pins

710

may also be replaced by dados in peripheral wall

704

and the panel with connecting biscuits.

Instead or in addition to the peripheral wall

704

, bottom

706

may be similarly varied as shown in

FIGS. 5

a

-

7

b

; i.e., bottom

706

may have pins, channels, studs, or other indentations or projections. Bottom

706

may also vary in depth (as measured from the intersection of the peripheral wall

704

and the exterior surface

702

) over its longitudinal direction if the panel is varied in thickness to match.

FIG. 8

a

is a cross sectional view of tube

800

mated to panel

806

, in a plane perpendicular to the axis of tube

800

, according to a fifth alternative embodiment of the invention.

FIG. 8

b

is a perspective view of tube

800

mated to panel

806

according this fifth embodiment. Panel

806

abuts both peripheral wall

802

, which mirrors the edge outline and thickness of panel

806

, and bottom

804

. In this fifth alternative embodiment of the invention, panel

806

is secured to tube

800

by a bead of welding

808

at their interior junction. While the bead of welding

808

may be located on the exterior junction, that embodiment somewhat mars the smoothness of the finished structure. Bead of welding

808

may be a normal longitudinal line or discontinuous as with spot welds.

FIG. 9

a

is a cross sectional view of tube

900

mated with panel

906

, in a plane perpendicular to the axis of tube

900

, according to a sixth alternative embodiment of the invention.

FIG. 9

b

is a perspective view of tube

900

mated with panel

906

according this sixth embodiment. This embodiment provides a more secure attachment of panel

906

to tube

900

. Peripheral wall

902

and bottom

904

still hold panel

906

in a load bearing relationship, but the attachment is carried out elsewhere. Tube

900

has bracket

908

, with an aperture

914

therein. Panel

906

has stud

910

which projects from panel

906

, through bracket

908

, and is secured therein. Bracket

908

may be equipped with a grommet (not shown) for better connection. In one alternative embodiment of the invention, stud

910

may be a screw or a bolt secured with a nut

912

.

In another alternative embodiment, bracket

908

is omitted, and a screw penetrates panel

910

and tube

900

through bottom

904

to secure them together. The screw head may be recessed, to retain streamlining of the exterior of the completed structure. Such a fastening method is shown in

FIG. 10

, which depicts a structure

1000

utilizing the components and methods disclosed herein. Structure

1000

is shown without a top panel so that the recess

1006

is visible. Panels

1008

are attached to the tubes

1002

and fittings

1004

with screws

1010

. Many other variations of attachment apparatus and fastening methods will be obvious to those skilled in the art.

In addition to the various mechanical fasteners discussed above, the panel may be secured to the panel recess using adhesives disposed between the contact surfaces of the two components. More than one type of fastener may also be used at the same time. Similarly, the various embodiments discussed above may be combined in one structure or even in one component without departing from the scope of the invention.

The invention and the best known mode of working it have been disclosed above in order allow practice of the invention by those skilled in the art, subject to retained patent rights. Many equivalents, substitutions and alternatives beyond those specifically detailed above will be obvious to those skilled in the art, without departing from the scope of the invention. Nothing in the above disclosure in any way limits the scope of the invention, which is limited only by the claims below.