Abstract:
A lighting tube fitting apparatus, method and system that allows movement of a lighting tube about two axes while preventing rotation about the longitudinal axis of the lighting tube it. A lighting tube within one of the disclosed fittings provides greater ability to align the electrode ends of a lighting tube with electrode holders. This reduces the need for the tight tolerances that are typically required in the art of conventional tube lighting. The movement of the lighting tube is enabled in the disclosed implementation using one or more pressure arcs within a clamp body make contact with a clamp ring that holds a lighting tube in place and prevents its rotation about its own axis. The lighting tube fittings provide the additional benefit of supporting the entire weight and position of the lighting tube, eliminating the need for any additional lighting tube supports along the length of the lighting tube.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims the benefit of the filing date of U.S. Provisional Patent Application 61/187,377 to Roger C. Bowser entitled “Lighting Tube Fitting,” which was filed on Jun. 16, 2009, the disclosure of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     This disclosure relates to lighting tube fittings and structures with specific application to custom made lighting tube holding devices. 
     2. Background Art 
     Holders for lighting tubes are known in the art. For example, various conventional fittings for holding neon tubes are illustrated and described in U.S. Pat. No. 4,947,301 to Charles Steele, entitled “Neon Tube Electrode Housing,” issued Aug. 7, 1990, the disclosure of which is hereby incorporated by reference. 
     Gas filled lighting tubes (tubes) became popular as the well known neon advertisement signs and have evolved into the familiar fluorescent tubes of standard lengths used in businesses and homes ubiquitously. These tubes are typically designed with two electrodes at each end and standard electrical fittings and plugs have been designed to facilitate the use of these tubes everywhere. Although gas filled lighting has been standardized in many aspects, custom lighting tubes still exists. Custom made lighting tubes continue to be used for advertisement and other target locations in a home or business where unique lighting is desired. These custom made lighting tubes typically include the standard two prong electrodes at each end of the tube connected to a power source that subsequently ionizes a gas within the tube to create luminescence. 
     One of the principle challenges of installing custom made lighting tubes in a sign or for other use is mounting of the lighting tubes on a fascia or within lighting housing. Each tube is generally a piece of custom glass work and the tube is formed in a particular shape with the electrodes of the tube designed for a targeted dimension to correspond with and be parallel with each other. The custom glass work, however, because each tube is manufactured separately, does not always align properly with the electrode holders and there exists the potential for the tube electrodes to not align properly with sign housing fixtures. 
     Because of the specific tolerances that must generally be met for a tube to attach to a conventional sign, it is not uncommon for the electrode ends to not be exactly parallel. Where a replacement lighting tube is manufactured to fit an existing lighting display, the alignment with both the electrode holders and with the existing tube supports may be desired but is difficult to achieve. The new lighting tube will often break during the installation process as an installer attempts to align the rigid glass tube into an existing support. In addition, once conventional tubes are installed in a sign, the tube is generally quite rigidly fixed in place, and there can be little or no adjustment of the positions of the electrodes. Because of this, an installer generally cannot perform any, or can only perform very few, adjustments of the electrode positions of the tube after installation to adapt to particular tube holders. Also, because the tube is rigidly fixed, thermal expansion stresses on the tube during seasonal operation can be significant, particularly if the electrode was installed touching one of the surfaces of the housing. In addition, because the tube supports are located along the surface of the sign, conventional tubes are manufactured to produce shapes within a single plane that is parallel with a back wall of the sign housing, allowing them to be within reach of the tube supports. 
     SUMMARY 
     The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS. 
     Implementations of lighting tube (tube) fittings are disclosed that hold a tube at the electrode ends and prevents movement of the tube relative to a central axis of the fitting and rotation, while permitting non-axial movement of the tube. Particular implementations of tube fittings disclosed in this document may provide the entire support of a tube at its electrode ends, and may not require the use of any additional tube supports along the length of the tube or face of the sign. In addition, tubes containing shapes out of a single plane of the sign may be utilized, as a result of the support of the tubes being provided at the tube ends. A wide variety of implementations of tube fittings are disclosed. 
     Implementations of a lighting tube fitting are disclosed for connecting and securing lighting tubes at their electrode ends to a fascia or other display housing. The lighting tube fitting includes a clamp body, at least one pressure arc and a clamp ring. The clamp body includes a side wall, a first and second end opening and at least two apertures. The pressure arc has a concave inner surface and an outer surface with at least two protrusions that are able to fit through the apertures in the clamp body. These protrusions may be rounded or dome shaped or may be any other geometric shape. The clamp ring has an inner diameter sufficiently large to receive an end of the clamp body. When a lighting tube is assembled with the clamp body, the protrusions of the pressure arcs extend through the apertures of the clamp body to contact and exert a force on the inner walls of the clamp ring. The lighting tube may fit in one opening end of the clamp body that has an inner diameter greater than 6 mm and may also include a threaded outer surface. 
     The clamp ring may also include protrusion grooves on the inner surface that align with the protrusions of the pressure rings and that permit rotation of the clamp ring with respect to the clamp body as the protrusions are maintained within the grooves. The outer surface of the clamp body or protrusions may be convex, but this is not necessary as long as the clamp ring is able to rotate about the outer surface of the clamp body. These protrusion grooves may have a slope that decreases in depth from the inner surface of the clamp ring and as it extends around the inner circumference of the clamp ring. The width of the protrusion grooves on the inner diameter of the clamp ring is greater than the width of the respective protrusions. Other grooves on the inner surface of the clamp ring may align with an angled flange on the outer surface of the clamp body and may include at least one angled groove wall to further engage the clamp ring to the clamp body. 
     Other implementations of the light tube fitting may use two or three pressure arcs instead of a single arc and each of the two or three arcs may have a protrusion that fits through a corresponding aperture in the clamp body. The protrusions may also be compressible with respect to the arcs themselves. Additionally, when assembled with a lighting tube, a tubular sleeve may be placed around the lighting tube or a coating may be included on the concave side of the pressure arcs before they are placed around the lighting tube. Furthermore, a relief sleeve may be coupled to the clamp ring at the electrode end of the lighting tube. 
     Another implementation disclosed is a method for securing and supporting a lighting tube by passing the electrode end of a lighting tube through an aperture to the first side of a fascia and placing a clamp body with at least one pressure arc inside the clamp body around the lighting tube. At least two protrusions extend from the surface of the pressure arc through apertures in the side wall of the clamp body. The first end of the clamp body slides back through the aperture in the fascia such that a majority of the clamp body is on a first side of the fascia and the first end of the clamp body extends through to the opposing side of the fascia. 
     A clamp ring slides around a first end of the clamp body and engages the clamp body by exerting a force against the at least two protrusions of the pressure arcs and on end of the clamp body is received in the clamp ring. This then exerts a force against the lighting tube within the pressure arc. The first end of the clamp body is secured to the fascia by coupling a fastener to the first end of the clamp body on the second side of the fascia. The clamp ring may include grooves that align and engage the protrusions extending through the apertures of the clamp body and allow rotation of the clamp ring about the clamp body as the protrusions are maintained in the grooves of the clamp ring. 
     After engaging the clamp ring with the clamp body and after securing the first end of the clamp body to the second side of the fascia, the adjusting of the lighting tube about at least one axis, but not more than two, is possible. Once the adjustments of the lighting tube are made for the first electrode end of the lighting tube, a second electrode end of the lighting tube may be secured with a second clamp body, pressure arc, and clamp ring in the same manner as the first electrode end of the lighting tube. 
     A lighting tube display system is also disclosed that includes a lighting tube with an electrode end that is secured to a display housing through an electrode port by the disclosed lighting tube fitting. The lighting tube fitting prevents the lighting tube from rotating about the longitudinal axis of the first electrode end but allows rotation about a second axis perpendicular to the longitudinal axis. It may also allow rotation about a third axis that is perpendicular to both the longitudinal axis and the second axis. This rotation may be limited to less than 4 degrees. 
     A second lighting tube fitting attached to a second electrode end of the lighting tube at a second electrode port of the display housing will secure the lighting tube to the display housing and prevent the lighting tube from rotating about any axis. Once the lighting tube is fixed at both electrode ends at the electrode ports of the display housing, the two lighting tube fittings will support the entire weight of the lighting tube. This eliminates the need for any additional supports along the length of the lighting tube within the display housing and allows a lighting tube to be designed beyond a single plane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS. 
       A more complete understanding of the disclosure may be derived by referring to the detailed description when considered in connection with the following illustrative figures. In the figures, like reference numbers refer to like elements or acts throughout the figures. 
         FIG. 1  illustrate an exploded view of a lighting tube fitting. 
         FIG. 2  depicts a cross sectional view of a clamp body assembly including the clamp body with the pressure arcs, tubular sleeve and a lighting tube inserted therein. 
         FIGS. 3A and 3B  depict a back side cross sectional view of two implementations of the clamp body assembly 
         FIG. 4  depicts a cross section of a clamp ring 
         FIG. 5  depicts an oblique view of the clamp ring 
         FIG. 6  depicts a cross sectional view of an assembled lighting tube fitting. 
     
    
    
     DESCRIPTION 
     In the following description, and for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various aspects of the inventions disclosed herein. It will be understood, however, by those skilled in the relevant arts, that the principles learned from this disclosure may be practiced by those of ordinary skill in the art without these specific details. In other instances, known structures and devices are shown or discussed more generally in order to avoid obscuring more pertinent features. In many cases, a description of the operation is sufficient to enable one to implement the various forms of the devices and methods. It should be noted that there are many different and alternative configurations, devices and technologies to which the disclosure may be applied. The full scope of the inventions is not limited to the examples that are described below. 
     One particular implementation of a lighting tube fitting that includes various elements is illustrated in  FIGS. 1-6  as a non-limiting example of the principles disclosed and discussed herein to describe other implementations. Referring specifically to  FIG. 1 , an exploded view of a lighting tube fitting with a clamp body  1  includes a first open end  2  with a threaded outer diameter  8  and an annular flange  6  and a second open end  4 . The clamp body  1  also includes at least two apertures  3  through the clamp body  1  and an annular flange  6  to secure the clamp body  1  against a fascia  30 . The fascia may be a single wall or include multiple sides of the entire frame of a lighting tube display housing. It should also be understood that the various embodiments and implementations disclosed herein are particularly useful for non-linear lighting tubes of the type that are typically used for gas-tube lighting sign designs. Linear lighting tubes are predictable because their lengths and electrode ends are predictable. Non-linear lighting tubes, however, because the manufacturing process is different, are much more difficult to manufacture with exactly aligned electrodes and exacting lengths. The clamp body  1  may also include at least two angular flanges  5  at an end of the clamp body  1 . 
     A lighting tube  60  with an electrode end  61  is inserted through a nut  40 , one or more washers  41 , a fascia or other lighting housing surface  30  and a tubular sleeve  25 . The electrode end  61  with the tubular sleeve  25  is surrounded by at least one pressure arc  20  that each include at least one protrusion  20   a  on the outside surface of the at least one pressure arc  20 . The lighting tube electrode end  61  combined with the elements of the tubular sleeve  25  and the pressure arcs  20  fits within the clamp body  1  such that the protrusions  20   a  of the pressure arcs  20  are inserted through the holes or openings  3  of the clamp body  1 . The clamp body  1  with the pressure arcs  20 , and one electrode end  61  of the lighting tube  60 , and the tubular sleeve  25 , combine to form one embodiment of a clamp body assembly  70  ( FIG. 2 ). 
     The clamp body assembly  70  is inserted into the second end  11  of a clamp ring  10  when the protrusions  20   a  of pressure arcs  20  are aligned with and slid into entry grooves  13  ( FIG. 4 ) of clamp ring  10 . A clamp body  1  with angular flanges  5  also may align with flange grooves  15  ( FIG. 4 ) of clamp ring  10  as protrusions  20   a  slide to the end of entry grooves  13 . Clamp ring  10  may then be rotated such that protrusions  20   a  and angular flanges  5  slide around the inner circumference of clamp ring  10  within pressure grooves  14  and flange grooves  15  respectively. The rotation of clamp ring  10  around clamp body assembly  70  may increase pressure on protrusions  20   a  as the protrusions  20   a  are slid within pressure grooves  14  that are sloped toward its longitudinal axis  62  ( FIGS. 3A and 3B ), closer to the inner diameter  16  of clamp ring  10 . The pressure arcs  20  are subsequently pushed closer together compressing tubular sleeve  25  and tightening the clamp body assembly&#39;s  70  hold on the electrode end  61  of the lighting tube  60 . 
     After the clamp ring  10  is rotated to a position that secures the clamp body  1  inside clamp ring  10 , the threaded first opening end  2  of clamp body  1  is inserted through a fascia  30 , until annular flange  6  is flush with the surface of fascia  30 . The fascia  30  may merely be a substrate of wood, plastic, wallboard or metal, or may be part of some larger lighting housing. Nut  40  is tightened around the threaded first end  2  of clamp body  1  such that washers  41  are tightened against one side of the fascia  30  and the annular flange  6  or a washer  41  and an annular flange  6  is tightened against the other side of fascia  30 . The first end opening  12  of clamp ring  10  may be attached to an electrode strain relief device  50 . Strain relief device  50  is not a required component of the lighting tube fitting in all embodiments and other coverings are contemplated as well. The electrode strain relief device  50  may be coupled to the outside of the clamp ring  10  as shown, or may alternatively be coupled to the inside of the clamp ring  10 . In particular implementations, the strain relief device  50  is weather resistant or moisture resistant to protect the electrodes extending from the lighting tube  60 . Weather resistant and moisture resistant strain relief devices  50  may be made, for example, of plastic, rubber, neoprene, silicon, or other resilient, water resistant material. As illustrated in  FIG. 6 , the strain relief device  50  in many implementations includes a chamber within the strain relief device  50  within which other insulated electrical conductors may be coupled to the bare electrodes extending from the lighting tube  60 . This in combination with a weather or moisture resistant strain relief device  50  helps to enable the couple to be used outdoors more safely. 
       FIG. 2  illustrates a cross sectional of the clamp body assembly  70  including a clearance  71  between the convex outer wall of pressure arc  20  and the concave inner wall of clamp body  1 . The clearance  71  of clamp body assembly  70  should be substantially equidistant at all diametric points between the outer surface of pressure arc  20  and the inner surface of clamp body  1 . Protrusions  20   a  may be rounded or may be of another specific geometric shape to allow for radial movement of the pressure arcs  20  within pressure grooves  14 . The protrusions  20   a  may be compressible with respect to the pressure arcs  20  and may or may not be fixed on the outer body of the pressure arcs  20 . Compressible protrusions  20   a , for example, may be formed of a compressible material such as a substantially rigid foam or other material that may compress slightly 
       FIGS. 3A and 3B  depict a cross sectional view of the clamp body assembly  70  perpendicular to the lighting tube longitudinal axis  62 .  FIG. 3A  shows clamp body  1  housing two pressure arcs  20 , a tubular sleeve  25  and lighting tube  60 . Pressure arcs  20  are held within the clamp body  1  by the protrusions  20   a  on the pressure arcs  20  inserted through openings  3  of the clamp body  1 .  FIG. 3B  shows a clamp body  1  housing an implementation of a single pressure arc  20   a , a tubular sleeve  25  and lighting tube  60 . It will be understood that the number of pressure arcs  20  in  FIGS. 3A and 3B  are not limitations on the scope or design of the disclosure and that one or more pressure arcs  20  may be used. In the example of  FIG. 3B , where only a single pressure arc  20  is used that surrounds a majority of the lighting tube  60 , the at least one pressure arc  20  still includes at least two protrusions  20   a  extending from an outer surface of the pressure arc  20 . Where only a single pressure arc  20  is used, the single pressure arc  20  is formed of a flexible material, such as a plastic, that permits the pressure arc  20  to flex like a clamp to squeeze against the lighting tube  60  when pressure is applied to the at least two protrusions  20   a . It will be understood from this disclosure that although in the particular implementation illustrated in  FIG. 2  the at least two protrusions  20   a  are illustrated directly across from each other, other implementations may not include the protrusions  20   a  positioned symmetrically about the circumference of the tube  60 . In another particular implementation it is contemplated that at least three pressure arcs  20  may be used, each with its own at least one protrusion  20   a.    
       FIG. 4  depicts an implementation of a cross sectional view of the clamp ring  10  with two open ends including a first end opening  12  with an inner diameter  17  larger than a standard or custom lighting tube and a second end opening  11  with an inner diameter  16  larger than the outer diameter  7  of clamp body  1 . Standard lighting tubes of the type relative to this disclosure come in sizes ranging from approximately 8 mm to approximately 25 mm in diameter, non-standard tubes will be close to that size, for example, ranging from approximately 5 mm to approximately 40 mm in diameter. Those of ordinary skill in the art will readily be able to adjust the relative dimensions of the components in this disclosure to adapt to specific tube diameters given the description provided here. Furthermore, it will be understood that particular component dimensions may be usable for a range of tube diameters because the use of the at least one pressure arc does not need to exactly fit each tube diameter to work properly. Because the at least two protrusions being compressed by the clamp ring  10  cause the at least one pressure arc  20  to apply pressure to the tube  60 , the fit does not need to be exact to prevent longitudinal rotation of the tube within the at least one pressure arc  20 . The clamp ring  10  may include two entry grooves  13  beginning at the edge and on the inside of the second opening  11  and continuing a distance parallel to the longitudinal axis  62  of the clamp ring  10  for a partial length. The entry grooves  13  allow the second end  4  of the clamp body assembly  70  to slide into the second end  11  of the clamp ring when the protrusions  20   a  of pressure arcs  20  align with and slide along the length of the entry grooves  13 . 
     The clamp ring  10  may also include pressure grooves  14  that are connected to the entry grooves  13  and extend for a distance around the inner circumference of the second opening  11 . The pressure grooves  14  may also slope towards the inner diameter  16  of the second end  11  of the clamp ring  10  from an initial depth equal to that of the depth of the entry grooves  13  to another reduced target depth. Including a slope on the pressure grooves  14  increases a force that presses the pressure arcs  20   a  towards the lighting tube  60  as the clamp ring  10  is rotated around the clamp body assembly  70  and the protrusions  20   a  of pressure arcs  20  slide within pressure grooves  14  around the inner circumference of clamp ring  10 . The pressure grooves  14  are of a sufficient width  19  that small movements of the protrusions within the grooves are possible in a direction other than about the longitudinal axis  62  of the clamp ring  10 . In particular implementations, it is contemplated that each end of a lighting tube  60  may individually have up to 5 degrees of radial movement from its longitudinal axis in directions other than about its longitudinal axis in relation to the clamp body  1  to allow for variations in tubes during a tube mounting process while still supporting the entire weight of the tube by only its ends. Once both ends of the tube are secured in respective ends, 
     Clamp ring  10  may also include flange grooves  15  on the inner circumference of the second opening  11  that allow flanges  5  on the outer circumference of the clamp body  1  to slide within the clamp ring  10 . The flange grooves  15  may include a groove wall that is angled with respect to the other groove wall. These grooves  15 , including an angled wall, would provide additional pressure and surface contact with flanges  5  between the clamp body  1  and the clamp ring  10  to further resist movement of the clamp body  1  with respect to the clamp ring  10  when securing the two together. 
       FIG. 5  depicts an oblique view of the clamp ring  10  including entry grooves  13 , pressure grooves  14  and flange grooves  15 . Second end opening  12  of clamp ring  10  allows the electrode end  61  of lighting tube  60  to connect to a power source and first end opening  11  has a large enough diameter to allow the second end  4  of the clamp body assembly  70  to be received into clamp ring  10 . 
       FIG. 6  depicts a cross section of the entire lighting tube fitting from  FIG. 1 , including a lighting tube  60  held within a clamp body assembly  70  ( FIG. 2 ) with the first threaded end  2  of the clamp body  1  inserted through a fascia  30  and secured by a fastener such as a nut  40  and washers  41  on one side of the fascia  30  and the annular flange  6  of the clamp body  1  on the other side of the fascia  30 . Longitudinal axis  62 , horizontal through the electrode end of the lighting tube  60 , and axis  24  represented vertically through the center point of protrusions  20   a  intersect at a point on a third axis  23  that goes into the page and is perpendicular to both axes  62  and  24 . The pressure arcs  20  hold the lighting tube  60  with friction layer  25 , which in the particular implementation of  FIGS. 1-6  is illustrated as a tubular sleeve  25 . Although the friction layer  25  is illustrated as a tubular sleeve  25  that surrounds the tube  60  in this particular example, it should be understood that the friction layer  25  may alternatively be merely a layer of friction material between the at least one pressure arc  20  or adhered to the at least one pressure arc  20 . Not all implementations will necessarily include a friction layer  25 . The pressure grooves  14  of clamp ring  10  secure protrusions  20   a  and prevent the lighting tube  60  from rotating about axis  62 . However, the lighting tube 70  is free to rotate a few degrees both about axis  24  in a left to right direction as well as about axis  23  in an up and down direction. 
     Various inserts and stress relief covers  50  may be utilized to protect and/or ensure that the wires extending from the lighting tube  60  are supported when they are connected to any of a wide variety of connecting cable types, such as, by non-limiting example, GTO, Neo-Pro, High Voltage (HV) silicone, and any other cable or wire type. In the particular implementation illustrated in  FIG. 6 , a stress relief cover  50  is included around the end of the clamp ring  10 . 
     In other particular implementations, a larger variety of sizes of lighting tubes  60  may be utilized with the same sized clamp body  1  and clamp ring  10  merely by changing the size of the pressure arcs  20  and/or the thickness of the friction layer  25  to match a particular tube diameter. This may allow the clamp body  1  and clamp ring  10  to serve as fairly universal parts while a user can use a specific pressure arc  20  and friction material  25  for particular sized tubing. 
     Any of a wide variety of features and structures may be employed with various implementations of tube fittings, using the principles disclosed in this document. The various Figures outlining a wide variety of options, structures, and assembly techniques may be employed in particular implementations. These examples are for the exemplary purposes of this disclosure and are non-limiting. For example, various systems and features exist for locking the position of a clamp ring  10  in place when a desired tightness has been reached. Various other designs for the clamp body  1 , clamp ring  10 , pressure arc  20 , and other parts of the tube fitting also exist. Using the principles disclosed in this document, a wide variety of implementations are possible. 
     Implementations of lighting tube fittings like those disclosed in this document may have many advantages over the current state-of-the-art. An example of an advantage is that lighting tubes connected to a sign using tube fittings, similar to those disclosed, may be held such that substantially no movement of the tube may occur once two fittings are used on both ends of the lighting tube, but adjustment of the position of the tube is still possible in non-axial directions when only one tube fitting is secured to one end of a lighting tube. A second example is that the need for high precision forming of tubes and the need for tube supports in the middle of a sign may be obviated through use of the disclosed tube fittings because the entire lighting tube can be supported at both ends by the disclosed tube fittings. This allows the use of non-planar lighting tube designs that extend from the plane of the sign without requiring tube supports in the middle of their extents. These examples are not the only advantages of the disclosed tube fittings and not all implementations have each of these advantages. Other advantages of the various implementations are not limited by those discussed here. 
     The materials used for implementations of lighting tube fittings may be made of a wide variety of conventional materials used to make goods similar to these in the art, such as, by non-limiting example, metals, plastics, rubbers, composites, ceramics, and the like. Those of ordinary skill in the art will readily be able to select appropriate materials having appropriate dielectric, ultraviolet (UV) resistance, heat resistance, and/or flame resistance properties and manufacture these products from the disclosures provided herein. 
     The implementations listed here, and many others, will become readily apparent from this disclosure. From this, those of ordinary skill in the art will readily understand the versatility with which this disclosure may be applied.