Abstract:
A luminous electric display unit having glass tubing, filled with an inert gas, fully or partially enclosed within a protective housing, thereby providing protection both for the glass tubing and the public.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of our U.S. patent application Ser. No. 08/819,821, filed Mar. 18, 1997, now abandoned which is a continuation-in-part of U.S. patent application Ser. No. 08/570,103, filed Dec. 11, 1995, now abandoned, which is a continuation of U.S. patent application Ser. No. 08/262,007, filed Jun. 17, 1994, now U.S. Pat. No. 5,533,286. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a luminous electric display unit of the inert gas-containing tube type. More particularly this invention is directed to a luminous electric display unit wherein the tube is partially protected with a transparent trough that is visible from all sides of the sign. 
     2. Description of Related Art 
     Luminous electric signs of the inert gas-filled tube type have long been employed in commercial and business establishments to provide decoration and/or impart information. Typically, such signs are referred to as “neon signs” and may be hung or placed in various locations, such as storefront windows, to advertise a product, decorate, or provide message information. 
     The tubular lighting elements of the sign may be conformed into an array of desired letters, logos, symbols, or decorative shapes, as in a glass tube-bending operation. The array is supportably attached by suitable brackets or wires to a rigid open frame, to a support backing, or to some form of housing or box. 
     In some situations, the housing that supports the lighting elements takes on special importance. For example, in applications such as food service, health care, schools, or any function involving children, safety is a primary consideration. When used in food service settings, the dust, foreign particles, and insects that tend to accumulate in neon signs become more than a mere nuisance, they may pose a contamination threat to food products in proximity. Luminous neon tube type signs, with their bright and varied colors, frequently draw the attention of children and can thus prove problematic because children are tempted to reach for the thin glass tubing. Moreover, governmental entities often place regulations on the use of luminous neon tube type signs in the above applications to guard against injury should the glass tubing break. 
     Security is another factor that retailers often consider when choosing a sign for advertising in and around their businesses. Many business owners want to maintain unobstructed sight lines to critical areas of their store or property to minimize opportunities for theft or other undesirable activity. Luminous neon tube type signs generally block the sight lines with their housing and thus are not used when unobstructed views are required. 
     As true of any product, manufacturing expense is always important. Housing for the components of a luminous neon tube type sign usually comes in multiple parts that must then be assembled. The additional assembly cost can add significantly to the manufacturing cost of the sign. 
     Various types of neon signs are known and found in the prior art. U. S. Pat. Nos. 1,570,980 to Wiegend, and 1,872,428 to Drury, show neon tube type signs where the glass tube is embedded in a groove to form the outline of a character or symbol. U. S. Pat. No. 5,267,404 to Kizy shows a neon tube type sign where the glass tube is mounted on a face plate that is in turn recessed within a rectangular housing. However, none of these signs completely cover the neon tube to protect the glass tubing from damage and to protect the public from injury. Kizy shelters the glass tube by placing the display unit within the housing, but the glass tube is still accessible from the front of the sign. U. S. Pat. No. 1,917,956 to Earley discloses a neon tube type sign where the glass tube is embedded in plaster and wax. While the plaster provides strong support for the tube, the front side of the tube is still exposed to the elements and thus may be soiled with insects, dust, and other foreign materials. 
     In addition, all of the above signs will block the sight lines wherever they are used and thus are not preferred where security is important. 
     None of the above signs use a single unit of material to totally encapsulate the glass tubing. Although Earley embeds the tubing in plaster and wax, the manufacturing process requires the plaster to be etched away in front of the tubing thus requiring a labor intensive step that defeats the benefits of complete encapsulation. 
     In view of the above, and in accordance with the present invention, it is desirable to provide a luminous electric display unit of the inert gas-filled tube type that protects both the glass tubing and the public from harm and keeps the glass tubing free from foreign debris. It is also desirable to provide a luminous electric display unit that is substantially transparent to allow for greater visibility of activities taking place in and around a place of business, for example. In addition, it is also desirable to reduce assembly expense by forming the housing from a single unit of material that encapsulates the glass tubing and is then sealed. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, one object of the present invention is to protect the lighting array of a luminous electric display unit of the inert gas-filled tube type from glass breakage and contamination by dust and foreign matter. 
     Another object is to protect the public from the dangers resulting from glass breakage or inappropriate handling of a luminous electric display unit. 
     Yet another object is to provide a luminous electric display unit that meets governmental regulations for use in food service or health care settings. 
     Still another object, in one form of the invention, is to provide a luminous electric display unit having a translucent housing thereby producing a substantially unobstructed view through the display unit. 
     An object of the present invention is to provide a luminous electric display unit wherein the illuminated tubing is visible from any angle of which the display unit is viewed. 
     And still further object, in one form of the invention, is to form the housing for the display unit from a single unit of material that is then molded to totally encapsulate and provide protection for the glass tubing held inside. 
     Also, another object of this invention is to provide a luminous electric display unit where the glass tube is not totally encapsulated and yet protected from environmental elements while remaining visible from all angles. 
     In accordance with another embodiment of the invention, both the face and back portions of the protective housing are made from a translucent material thereby minimizing any visual obstruction through the display unit. 
     In accordance with still another embodiment of the invention, the protective housing is made from a single unit of material that is then molded to encapsulate the glass tubing. 
     Further objects and advantages will become apparent from a consideration of the following description and drawings. 
     According to the present invention, the foregoing and other objects and advantages are attained by providing a luminous electric display unit having a protective housing that comprises a back portion and a face portion. The back portion has elongated grooves that are recessed from the face portion for receiving a gas filled glass tube. The face portion holds the glass tubing in place in the elongated grooves and also protects the tubing from damage or contamination by foreign debris. Electrical circuitry located behind the back portion of the housing illuminates the tubing when the circuitry is connected to a power source. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a first embodiment of an electric luminous display unit of the present invention; 
     FIG. 2 is a right side elevation view of the display unit of FIG. 2 taken generally along lines II —II and looking in the direction of the arrows; 
     FIG. 3 is a front elevation view of the display unit of with the glass tubing removed to better show the grooves in the back portion of the unit, which receive and protect the tubing; 
     FIG. 4 is a front elevation view of the glass tubing of the luminous display unit of FIG. 1; 
     FIG. 5 is a rear elevation view of the glass tubing of the luminous display unit of FIG. 1; 
     FIG. 6 is a rear elevation view of the glass tubing of the luminous display unit of FIG. 1 showing the connection of the electrical circuitry to the tubing; 
     FIG. 7 is a sectional view of the display unit of FIG. 1, taken generally along lines VII—VII and looking in the direction of the arrows; 
     FIG. 8 is a right side perspective view of a second embodiment of the present invention showing the housing made of a single unit of material; 
     FIGS. 9 is a broken-away perspective view showing one technique for affixing the face portion of the unit to the back portion; 
     FIG. 10 is a broken-away perspective view showing a second technique for affixing the face portion of the unit to the back portion; 
     FIG. 11 is a broken-away perspective view showing a third technique for affixing the face portion of the unit to the back portion; 
     FIG. 12 is a broken-away perspective view showing a fourth technique for affixing the face portion of the unit to the back portion; 
     FIG. 13 is a perspective view showing a “blister pack” design for attaching the face and back portions to one another; 
     FIG. 14 is a front elevation view of a third embodiment of the electric luminous display unit; 
     FIG. 15 is a bottom plan view thereof; 
     FIG. 16 is a side elevation view, the opposite side being a mirror image thereof; 
     FIG. 17 is a partial blown-up front elevation view of the top portion of the electric luminous display unit; 
     FIG. 18 is a broken-away partial view of the connecting means; 
     FIG. 19 is a cross-sectional view of the top portion of the electric luminous display unit taken along line III —III in FIG. 17; 
     FIG. 20 is a front elevation of a fourth embodiment of the electric luminous display unit; 
     FIG. 21 is a side elevation view thereof, the opposite side being a mirror image; 
     FIG. 22 is a top plan view of the fourth embodiment; 
     FIG. 23 is a bottom plan view of the fourth embodiment; 
     FIG. 24 is a side elevation view of a fifth embodiment of the electric luminous display unit; 
     FIG. 25 is a front elevation view of the fifth embodiment thereof; 
     FIG. 26 is a cross-sectional view of the side of the electric luminous display unit taken along line IV—IV in FIG. 25; 
     FIG. 27 is a front perspective view of the fourth embodiment of the electric luminous display unit; and 
     FIG. 28 is a front perspective view of the fifth embodiment of the electric luminous disply unit. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, an improved luminous electric display unit that meets and achieves the various objects of the invention set forth above is shown. 
     As seen in FIGS. 1 through 4, electrical luminous display unit  10  includes support housing  12  having a substantially rigid face portion  14  and a substantially rigid back portion  16 . Back portion  16  is preferably comprised of a thermo-formable material while face portion  14  can be constructed from a less expensive material. Back portion  16  contains one or more elongated grooves  18 ,  20  for the receipt and protection of elongated glass tubing  22 . The back portion  16  also has a lip  23  around the perimeter of said back portion for helping to maintain said face portion  14  in position when it is connected to the back portion  16 . The face portion  14  also rests upon a shoulder  24  formed in the back portion  16 . The shoulder  24  allows the front portion  14  to be adjacent to the back portion  16  when connected thus making any type of connection stronger and sturdier. Glass tubing  22  contains an inert gas, such as neon, that is electrically excited via transformer  28  and cables  26  to illuminate tubing  22 . Tubing  22  forms the word “OPEN” surrounded by a generally rectangular border in the referred embodiment, however, any arrangements of letters can be formed and used in the display unit. To dissipate heat emanating from glass tubing  22  and transformer  28 , back portion  16  contains vent holes  4  allowing cool air to enter the sign near the bottom and warm air to escape from the top of the sign. 
     Glass tubing  22  for containing the inert gas is bent, as in a heat-shaping operation. In such a shaping operation, a single length of tubing forms the entire word, e.g., OPEN, and the rectangular border. To separate and distinguish the letters, transition portions  22   a  of the length of tubing are, where practical, bent to lie primarily in a plane separate from the plane of the letters of the message to be conveyed (See FIGS. 1,  4  and  5 ). Transition portions  22   a  are also covered with an opaque coating to minimize the amount of light escaping from that portion of the tubing  22 . 
     As shown in FIGS. 2,  5  and  6 , transformer  28  and cables  26  are used to deliver electrical power to display unit  10  from a conventional 120V AC power supply. Once energized, the gas illuminates the display unit  10  by transmitting light through the transparent portions of tubing  22 . Transformer  28  is preferably positioned in an area of back portion  16  having no recessed grooves  20  (i.e., behind island  90  areas). This allows the overall width of the sign to be reduced to essentially the width of the transformer  28  plus the thickness of the materials comprising both face portion  14  and back portion  16  as shown best in FIG.  2 . One clear advantage of reducing the overall sign thickness is that the sign can be hung against a wall instead of just from a ceiling. For maximum safety from electrical hazards, the transformer  28  could be encased in plastic such that the only component external to the housing  12  would be the power cord. 
     FIGS. 1,  3 , and  7  show the encapsulation of glass tubing  22  within grooves  18 ,  20  and face portion  14 . Glass tubing  22  is held in place by grooves  18 ,  20 , face portion  14 , and islands  90 . Grooves  18 ,  20 , face portion  14 , and islands  90  combine to provide protection both for the tubing  22  and the public. Rubber bushings  32  are used to position glass tubing  22  in grooves  18 ,  20  to ensure a tight fit. Alternative means, such as plastic clips, or sponge cushioning could be used instead of rubber bushings  32 . 
     FIGS. 7 and 9 through  13  illustrate various mechanisms that can be used to secure the face portion  14  to the back portion  16 . Face portion  14  is received into back portion  16  along lip  40  as shown in FIG.  7 . Bolts  29  and nuts  30  are used to secure face portion  14  to back portion  16 . In one common embodiment, face portion  14  is secured to back portion  16  via a “blister pack” seal (see FIG.  13 ). This technique requires raised regions  50   a,b  (i.e., blisters) that are dispersed about either face portion  14  (as shown in FIG. 13) or back portion  16  and extend towards the other portion. The raised regions  50   a,b  are exactly the same size and shape as their corresponding apertures  52   a,b . Therefore, when the raised region  50   a,b  is inserted into the corresponding aperture  52   a,b,  the raised region  50   a,b  is squeezed slightly to fit within the corresponding aperture  52   a,b  forming a friction fit. The portions of the housing without the blisters or raised regions  50   a,b  have corresponding apertures  52   a,b  that are designed to receive blisters  50   a,b  and thus secure the two portions together via friction. The shape and position of blisters  50   a,b  and apertures  52   a,b  can be modified to suit the shape and contents of housing  12 , so long as the blisters  50   a,b  correspond in size and shape to the apertures  52   a,b . For example, a long narrow blister  50   a  and aperture  52   a  combination may be used along the edges of the display unit  10  while smaller, square shaped blisters  50   b  and apertures  52   b  may be used at the corners. Still another approach for attaching face portion  14  to back portion  16  involves forming lips  23  that extend from the edges of one or both portions. When the two portions are placed together, the lips  23  hook over an opposing edge or lip to ensure a secure fit. Other alternatives for securing face portion  14  to back portion  16  include: an adhesive  31  (FIG.  9 ), staples  33  (FIG.  10 ), clips  35  (FIG.  11 ), screws  37  (FIG.  12 ), heat melting, thermo-seal, ultrasonic welding, or other known securing means. 
     Face portion  14  is made from a translucent material. Back portion  16  is opaque for daylight applications and is preferably translucent for indoor, night time, or applications requiring an unobstructed view through the sign. 
     FIG. 8 shows yet another embodiment where a single piece of material is used to form both face portion  14  and back portion  16  of housing  12 . In forming housing  12 , back portion  16  should be comprised of a thermo-formable material. As part of the thermo-form process, a mold is impressed upon the heated material to form grooves  18 ,  20 , which vary in depth, in back portion  16  (see FIG.  7 ). Deeper grooves  18 ,  20  are used to receive segments of transition portions  22   a  allowing those portions of tubing  22  to lie in a separate plane than the portions forming the letters. Face portion  14  is often comprised of a thin, pliable material that is relatively inexpensive. Since face portion  14  does not carry any load bearing responsibility, its composition and design is primarily dictated by the degree of protection required for tubing  22  and the public. Also, as shown in FIG. 8, the material is folded along flexible hinge  17  such that face portion  14  and back portion  16  oppose one another. Flexible hinge  17  is commonly a score line, but alternative embodiments are envisioned where separate hinge hardware is used to join face portion  14  to back portion  16 . Face portion  14  and back portion  16  are then secured to each other using a blister pack seal  50   a,b  or any of the other means discussed above. By using a unitary piece of material to form the entire housing, manufacturing costs are reduced because fewer steps are required. For example, the housing is commonly placed on what is known in the industry as a “trim dye”. Next, excess material is trimmed away to form the housing&#39;s shape and then holes and grooves are impressed upon the housing as desired. When a unitary piece of material is used to form the entire housing, these steps can be performed in one session on the dye. By contrast, multiple housing components each require their own session on the trim dye. In addition, a light weight, yet safe, display unit can be constructed by reducing the densities of face portion  14  and back portion  16  where appropriate. 
     FIGS. 14,  15  and  16  are directed toward the third embodiment in the electrical luminesce display unit  110 . This third embodiment is comprised of a support housing  112  which has a front face portion  114  and a back portion  116 . Along the perimeter of the support housing  112  is a trough  119  which holds a glass tubing  122 . The trough  119  is connected to the back portion  116  and integrally formed therewith on one edge of the trough  119  such that one edge of the trough  119  is connected to the back portion  116  while the other edge of the trough  119  is not connected to any part of the housing  112 , it just extends out away from the housing  112 . A glass tubing  122  is held within the trough  19  by a retention wire  160  and at every location of a retention wire  160  there is also a bushing  132  placed between the glass tubing  122  and the trough  119  to prevent the glass tubing  122  from being damaged. At the top of the support housing  112  there is a hanger portion  162  formed therewith. This hanger portion  162  is integrally formed with the housing  112 , either the front face portion  114  or the back portion  116 . The hanger portion  162  allows the electric luminous display unit  110  to be hung from a support structure such as a ceiling or a wall. Connected to the hanger portion  162  are chains  166 , or any other type of conventional hanging unit, that allow the electric luminous display unit  110  to be hung. Electrical circuitry is located within the housing  112  or between the back portion  116  and the front portion  114  of the housing  112 . The electrical circuitry is connected to the glass tubing  122  and illuminates the glass tubing  122  when the circuitry is connected to a power source. 
     FIG. 17 is a partial blown-up front elevation view of the top portion  114  of the electric luminous display unit  110 . In this figure, chain elements  166  are connected to connecting means  168  which are connected to the hanger portion  162  allowing the electric luminous display unit  110  to be hung from a support structure. FIG. 17 more clearly discloses the trough element  119  that holds the glass tubing  122 . The glass tubing  122  is held within the trough unit  119  by retention wire  160 . Between the glass tubing  122  and the trough unit  119 , a bushing  132  is placed to hold the glass tubing  122  firmly in place and prevent it from being damaged by the trough unit  119 . Transition portions  122   a  of the glass tubing  122  are shown protruding out of the top of a tubing aperture  184  in the top part of the rigid faced portion  114 . Also depicted in this figure is the flap element  170  and its relationship to the tongue element  172 . The flap element  170  and the tongue element  172  are the means that connect the face portion  114  with the back portion  116 , forming the entire support housing  112 . The tongue element  172  has a slot located on each side thereof, and the flap  170  fits within the slots in such a manner that the tongue  172  and flap  170  are adjacent one another or nested together in a parallel fashion forming a locking mechanism. 
     FIG. 18 shows a broken-away partial view of the connection between the flap portion  170  and the tongue portion  172  as previously described. The inner edge of the trough portion  119 , within which is held the glass tubing  122 , forms the flap region  170  which overlaps with the tongue region  172  of the face portion  114 . In the face portion  114 , slots  180  are cut out forming the tongue portion  172 . In the inner portion of the trough  119  which forms the flap  170 , an aperture or apertures  182  are cut within the flap portion  170  to form an opening within which the tongue  172  is slid into forming, a tight friction formed connection means thereby connecting base portion  114  with the back portion  116 . 
     FIG. 19 is a cross-sectional view of the top portion of the electric luminous display unit  110 . In this figure the relationship between the front face portion  114  and the back portion  116  is more clearly depicted. Both the face portion  114  and the back portion  116  are preferably comprised as a thermo-formable material. The back portion  116  extends up into the trough portion  119 , the trough portion  119  extends up into the hanger portion  162 , and the hanger portion  162  is attached the chain  166  for hanging the entire electric luminous display unit  110 . The glass tubing  122  is inset in the trough  119 . The glass tubing  122  is held within the trough  119  by the retention wire  160 . Located between the glass tubing  122  and the trough  119  is placed a bushing  132  to help hold the glass tubing  122  securely in place within the trough  119  and also to prevent it from moving and damage. As shown in this figure, the back portion  119 , the trough  119  and the hanger portion  162  are all integrally formed and comprised of one continuous piece of thermoformable material. The trough  119  extends outside an exterior to the support housing  112 . This allows the glass tubing  122  to be visible from any angle when the electric luminous display unit  110  is viewed. 
     FIGS. 20,  21 ,  22 ,  23  and  27  disclose the fourth embodiment of the electric luminous display unit  210 . This fourth embodiment differs from the previous embodiments in that the glass tubing  222  is inlaid within groove  218  both on the face portion  214  as well as the rear portion  216  of the electric luminous display unit  210 . The electric luminous display unit  210  again is comprised of a face portion  214  and a rear portion  216  of an overall support housing  212 . The glass tubing  222  is retained within groove  218  by retention wire  260 . The face portion  214  and the rear portion  216  of the support housing  212  are two separate pieces that are connected together along rim  286  that runs the perimeter of both the face portion  114  and the back portion  116 , with the face portion rim (not shown) being placed inside the back portion rim  286  and connected together with connecting means  274 . These connecting means can be any conventional type of connecting means such as screws, staples, bolts and the like. This fourth embodiment of the electric luminous display unit  210  can also be hung using hanging means  276 . Located in both the top and the bottom of the support housing  212  and on both the face portion  214  and the rear portion  216  are located air vents  278 . These vents  278  allow the air within the support housing  212  to enter and escape thus prevent the electric luminous display unit  210  from overheating. 
     FIGS. 24,  25  and  28  depict a fifth embodiment of the electric luminous display unit  310 . This fifth embodiment is similar to the third and fourth embodiments with the support housing  312  being comprised of a thermoformable material having two separate portions, one being the rigid face portion  314  and the other being the back portion  316 . This embodiment also has a hanger portion  362  which has some type of conventional hanging means such as a chain  366  connected thereto with a connecting means  376 . Around the perimeter of the support housing  312  is a trough  319  within which is housed a glass tubing  322 . The glass tubing  322  is retained within the trough  319  by retention wires  360  and placed between the glass tubing  322  and the trough portion  319  are bushing elements  332  which help to hold the glass tubing  322  in place and prevent it from damage from the trough portion  319 . The face portion  314  is connected to the rear portion  316  in the same manner or similar manner as in the fourth embodiment, that is, the rim (not shown) of the perimeter of the face portion  314  is inserted within the rim  386  of the back portion  316  and connected together with conventional connection means  374  such as screws, bolts, staples and the like. The difference between the fourth and the fifth embodiment is that in the fifth embodiment, the rim  386  of the rear portion  316  continues on and is integrally formed with the trough  319  which holds glass tubing  322 . 
     FIG. 26 is a cross-sectional view of the side of the electric luminous display unit  310  showing the connection between the front face portion  314 , the back portion  316  and the trough  319  that partially encapsulates the glass tubing  322 . The front face portion  314  extends from the front of the electric luminous display unit  310  to the side where it forms a rim  386  and continues on in a curved fashion to form the trough  319  within which is placed the glass tubing  322 . As in previously described embodiments, the glass tubing  322  is maintained within the trough  319  by retention wires  360  placed intermittently around the perimeter of the electric luminous display unit  310 . Placed within the trough  319  and between it and the glass tubing  322  are bushings  332  to prevent the glass tubing  322  from hitting the surrounding trough  319  and becoming damaged or broken. The encompassing nature of the trough  319  protects the glass tubing  322  from breakage an vandalism as well as allows the glass tubing to be visible from various angles. While the face portion  314  and the back portion  316  may be either opaque, colored or transparent, the trough  319  itself is transparent, thus allowing for expanded visibility. However, if desired, the trough  319  can also be opaque or colored. 
     Thus it can be seen from the foregoing detailed description, that the present invention provides a safe, economical, luminous electrical display unit  310 . Features such as total and partial encapsulation of the glass tubing  322 , for the protection of both the tubing and the public, and a translucent housing  312  or the  322  tubing being located around the perimeter of the display unit  310  that provide an unobstructed view through the display unit  310 , overcome many of the safety drawbacks found in prior art display units. Moreover, using a unitary piece of material, in a few of the embodiments, for the display unit housing  312  significantly reduces manufacturing costs. 
     While the above description contains many specificities, it is understood that many variations are apparent to one of ordinary skill in the art from a reading of the above specification. Such variations are within the spirit and scope of the present invention as defined by the following claims: