Patent Publication Number: US-9402498-B2

Title: Safety grounded tree

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to artificial lighted trees. Specifically, embodiments of the present invention provide for a decorative lighted Christmas tree with power routed through the trunk of the tree and three-wire safety grounding. The tree is divided into sections for easy assembly, disassembly, and storage. Safety electrical contacts at the ends of each section are not powered until the sections are assembled. The tree can also accommodate multiple lighting circuits utilizing different voltages simultaneously. 
     BACKGROUND OF THE INVENTION 
     Seasonal lights, such as those used in conjunction with Christmas trees, are well known in the art. These seasonal lights generally use two-wire conductors to provide power to each of the light bulbs on a particular strand. Since insulation covers the entire length of the wire and plug, risk of shock is minimal so grounding is not a major issue. 
     Further, artificial pre-lighted Christmas trees, where the seasonal lights are incorporated on or with the tree, have become a popular alternative to both live trees and unlighted artificial trees. These trees are usually sectional for easy storage, with some lighted trees routing power for the lights up through the trunk of the tree with electrical connectors built into the ends of each tree section to distribute power to each section. This mechanism, although convenient, brings with it the risk of exposed conductors at every electrical junction. If these exposed wires accidentally make contact with any other portion of the artificial tree, there is a risk of electric shock and other undesirable electrical dangers (e.g., fire). 
     Therefore, there is a need in the art for a lighted artificial Christmas tree with a 3-wire safety ground and electrical connectors which prevent electric shock when the contacts are accidentally touched. These and other features and advantages of the present invention will be explained and will become obvious to one skilled in the art through the summary of the invention that follows. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an artificial lighted tree with power routed through a hollow trunk and three-wire electrical grounding, where the trunk itself is conductive and grounded. 
     It is also an object of the present invention to provide an artificial lighted tree where the trunk is divided into sections and safety electrical connectors at the end of each section prevent power from being connected to the exposed contacts at the top end of any trunk section until the bottom end of another trunk section is connected to it. 
     It is also an object of the present invention to provide a multi-conductor system in the artificial lighted tree which is capable of carrying a variety of different voltages allowing for different types of lights to be used on the same tree. 
     According to an embodiment of the present invention, a lighted artificial tree comprising a base configured to receive and hold a trunk. The trunk comprises a hollow body having an electrically conductive wall, one or more inner electrical conductors situated inside the hollow body, one or more side electrical connectors accessible from the outside of the hollow body and electrically connected to said inner electrical conductors, a ground conductor, electrically connected to the electrically conductive wall of the trunk, and a branch holding mechanism configured to attach one or more artificial tree branches to the trunk. 
     According to an embodiment of the present invention, the trunk comprises two or more trunk sections. Each trunk section comprises a hollow body having an electrically conductive wall, a male electrical connector attached inside a first end of the hollow body, and a female electrical connector attached inside a second end of the hollow body. The first end of one trunk section connects to the second end of a second trunk section causing the male electrical connector to connect to the female electrical connector and electrically connecting the electrically conductive walls of the first trunk section and the second trunk section. One or more inner electrical conductors connect the female connector to the male connector within a trunk section. 
     According to an embodiment of the present invention, the electrically conductive wall of the first trunk section makes a direct electrical connection with the electrically conductive wall of the second trunk section when the two trunk sections are connected together. 
     According to an embodiment of the present invention, the male electrical connector comprises a male ground contact corresponding to a female ground contact in the female electrical connector for creating an electrical connection between the electrically conductive walls of the first trunk section and the second trunk section. 
     According to an embodiment of the present invention, a limiting collar controls proper insertion depth between the first trunk section and the second trunk section. 
     According to an embodiment of the present invention, the male electrical connector comprises a center male contact terminal, and one or more side male contact terminals. The female electrical connector comprises a fixed center terminal, a movable center safety contact configured to move into electrical contact with the fixed center terminal when the center male contact terminal contacts the movable center safety contact, one or more fixed side terminals, and one or more movable side safety contacts configured to move into electrical contact with the fixed side terminal when the side male contact terminal contacts the movable side safety contact. 
     According to an embodiment of the present invention, the movable center safety contact and the movable side safety contacts are not energized until the male electrical connector and the female electrical connector are connected together causing the movable center safety contact to move into contact with the fixed center terminal and one or more movable side safety contacts to move into contact with one or more fixed side terminals. 
     According to an embodiment of the present invention, the side male contact terminal is a cylindrical contact ring; and the movable side safety contacts are arranged symmetrically such that the female electrical connector and the male electrical connector are capable of connecting in a plurality of rotational orientations to produce redundant electrical contact between the cylindrical contact ring and the plurality of movable side safety contacts. 
     According to an embodiment of the present invention, the male electrical connector further comprises a plurality of side male contact terminals. The female electrical connector further comprises a plurality of fixed side terminals, a plurality of movable side safety contacts, and a plurality of independent conductors each connected to one of the plurality of fixed side terminals. The first end of the first trunk section connects to the second end of the second trunk section in only a single orientation by means of a keying mechanism in at least one of a) the trunk sections; or b) the electrical connectors. 
     According to an embodiment of the present invention, the tree has multiple independent power conductors for running a plurality of different voltages. 
     According to an embodiment of the present invention, the tree further comprises a foot pedal configured for at least one of a) turning power on and off; and b) switching between various different lighting modes. 
     According to an embodiment of the present invention, the foot pedal further comprises fuses. 
     The foregoing summary of the present invention with the preferred embodiments should not be construed to limit the scope of the invention. It should be understood and obvious to one skilled in the art that the embodiments of the invention thus described may be further modified without departing from the spirit and scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of the entire tree showing three-wire ground connections, and the various main parts of the tree. 
         FIG. 2  shows the tree with multiple trunk sections and the detailed anatomy of a trunk section. 
         FIG. 3A  is a cutaway side view of the multi-conductor male and female safety connectors showing how the movable side safety contacts are not powered when the male and female electrical connectors are disconnected from each other. 
         FIG. 3B   2  is a cutaway side view of the multi-conductor male and female safety connectors when connected together showing how the movable side safety contacts have moved into contact with the fixed side terminals, completing the electrical path between the male and female electrical connectors. 
         FIG. 3C  is a bottom and top view of the multi-conductor male and female safety connectors respectively. 
         FIG. 3D  is bottom and top view of the male and female safety connectors where the male electrical connector has a conductive ring, and the female electrical connector has redundant side connectors for ensuring a proper connection in a plurality of rotational orientations. 
         FIG. 3E  is a cutaway side view of the male and female safety connectors where the male electrical connector has a conductive ring, and the female electrical connector has redundant side connectors for ensuring a proper connection in a plurality of rotational orientations. 
         FIG. 4  is view of male and female plugs with a third electrical connection for ground. 
         FIG. 5A  shows a side profile view of the secondary connector in the side of the tree trunk for making power accessible from outside the tree trunk. 
         FIG. 5B  shows a face view the secondary connector attached to the side of the tree trunk for making power accessible from outside the tree trunk. 
         FIG. 6  shows a foot pedal switch with three-wire safety ground conductors running through it and fuses. 
         FIG. 7  shows the entire tree with side connectors and a two-prong connector between the trunk sections 
         FIG. 7A  shows the detail level of the two-prong connector from  FIG. 7   
         FIG. 7B  shows the detail level of the side electrical connector from  FIG. 7   
     
    
    
     DETAILED SPECIFICATION 
     The present invention generally relates to artificial lighted trees. Specifically, embodiments of the present invention provide for a decorative lighted Christmas tree with power routed through the trunk of the tree and three-wire safety grounding. The tree is divided into sections for easy assembly, disassembly, and storage. Safety electrical contacts at the ends of each section are not powered until the sections are assembled. The tree can also accommodate multiple lighting circuits utilizing different voltages simultaneously. 
     According to an embodiment of the present invention,  FIG. 1  shows an artificial lighted tree  100  comprising two primary parts: a base  101  and a trunk  102 . One of ordinary skill in the art would recognize that the trunk and base may be attached to each other by a variety of means. Examples of attachment means include, but are not limited to, welding, screws, bolts, adhesives, or the trunk may merely be held upright by the base while resting on a surface. The trunk  102  is preferably electrically conductive or has an electrically conductive wall. To reduce the risk of electric shock, the tree  100  in  FIG. 1  is safety grounded using a third wire that goes into the third hole in a grounded power outlet. As shown in  FIG. 1 , according to one embodiment of the present invention, grounding is accomplished by electrically connecting the neutral wire  103  to the ground wire  104  by attaching them both to the conductive trunk  102  of the tree  100 . One of ordinary skill in the art would recognize there are a variety of ways to achieve proper grounding. The neutral wire  103  and the hot wire  108  then run up the inside of the trunk routing power to lights that decorate the tree. One of ordinary skill in the art would recognize that wires are not necessary, and any conductor can be used, including, but not limited to, printed circuits, conductive paints, conductive liquids, or ionized gases. Embodiments of the present invention may incorporate one or more of these conductors in lieu of or in conjunction with the wires. 
       FIG. 1  also shows a side electrical connector  107  which provides access to the hot wire  108  and neutral wire  103  inside the trunk  102  from outside the trunk  102 . The side electrical connector  107  may be as simple as a wire, electrically connected to the wires  108 ,  104  inside the tree  100 , and merely passing through a hole in the trunk  102  to the lights on the tree, or it may be a complex detachable multi-conductor connector as depicted in  FIG. 5 , described later in this specification. Another embodiment of the side electrical connector is shown in  FIG. 7A . One of ordinary skill in the art would appreciate that there are numerous types of side electrical connectors that could be utilized with embodiments of the present invention, and embodiments of the present invention are contemplated for use with any appropriate type of side electrical connector. 
     According to a preferred embodiment of the present invention, the tree  100  also includes a branch attachment means  105 . The branch attachment means  105  may permanently secure the branches to the tree or the branches may be removable. If the branches are permanently attached to the tree, they may be hinged  106  to allow the branches to fold upward for compact storage. Branch attachment means  105  may include, but are not limited to, screw fittings, snap fittings, hinged fittings, or any combination thereof. One of ordinary skill in the art would appreciate that there are numerous types of branch attachment means that could be utilized with embodiments of the present invention, and embodiments of the present invention are contemplated for use with any appropriate type of branch attachment means. 
     According to a preferred embodiment of the present invention in  FIG. 1 , a three-pronged plug  110  allows the entire tree  100  to be properly grounded when plugged into a grounded power outlet. Finally, a fuse box  109  attached to the side of the trunk  102  or the base  101  of the tree  100  houses appropriate fuses which will cut off power in case of a short or other electrical fault. Alternatively fuses may be housed inside an optional foot pedal controller shown in  FIG. 6 , or inside the plug  110  itself. 
       FIG. 2  shows the trunk of the tree  200  divided into separable trunk sections  202 . According to an embodiment of the present invention, each trunk section has a male safety connector  203  in one end and a female safety connector  204  in the other end, allowing the trunk sections  202  to be assembled in any order. It is important to note that female electrical connectors and male electrical connectors are merely two connectors that connect to each other. Neither connector needs to be unambiguously anatomically male or female. So long as the connectors connect to each other, one may be accurately considered male and the other female. The trunk sections  202  need not all be of the same length. The male and female safety connectors  203 ,  204  are described in greater detail later in  FIG. 3A-3E . The wires  205  connect the male safety connector  203  to the female safety connector  204 , routing power to the side connectors and the next trunk section. 
     According to an embodiment of the present invention, The ground connection  208  is made in the base  201  itself which incorporates a female safety connector  204  to allow any trunk section  202  to connect to the base  201 . 
     In a preferred embodiment of the present invention, a foot pedal  209  can be connected in line with the power cord to control the lighting of the tree. In other embodiments, the control of the lighting of the tree may be controlled by one or more control elements, such as a switch, a selector knob, an indicator panel, or any other human interface device (HID) or any combination thereof. One of ordinary skill in the art would appreciate that there are numerous types of control elements that could be utilized with embodiments of the present invention, and embodiments of the present invention are contemplated for use with any type of control element. 
     According to an embodiment of the present invention, a trunk section may also include a multi-conductor divider harness  206 . This divider harness  206  allows power to be branched off to various multi-conductor divider harness side electrical connectors  207  and between the male safety connector  203  and the female safety connector  204 . Alternatively, the divider harness  206  may enable the use of a plurality of circuits running at different voltages incorporated into the tree  200 . With multiple circuits running through independent conductors, the user has the option of using both AC and DC voltages and a variety of different voltage levels simultaneously, including but not limited to 3 VDC, 5 VDC, 12 VDC, 24 VDC, 36 VDC, 120 VAC, 230 VAC, 50 Hz AC, or 60 Hz AC. When using multiple independent circuits, the divider harness  206  serves the function of routing the correct wires to the correct multi-conductor divider harness side electrical connectors  207  and between the male safety connector  203 , and female safety connector  204 . A multi-conductor safety connector will now be explained, referring to  FIG. 3A-3C . 
       FIG. 3A  shows the cutaway side view of the male electrical connector  301  and female electrical connector  302  components of the multi-conductor safety connector. The mechanics of the safety connector will now be explained. According to an embodiment of the present invention, the multi-conductor male electrical connector  301  contains a common center male contact terminal  303  and multiple side male contact terminals  304 . These terminals  303 ,  304  are embedded in or attached to a male insulator  306 . These terminals  303 ,  304  pass through the male insulator  306  and fold over to rest against the top surface of the male insulator  306 , securing them in place and providing a larger contact surface for the outgoing wires  305 ,  313  to make electrical contact. A male wire insulator  307  has outgoing wires  305 ,  313  passing through L-shaped holes. When the male wire insulator  307  is fastened to the male terminal insulator  306  with screws  308 , the ledge formed by the L-shaped hole presses the exposed tip of the outgoing center wire  305  against the top end of the center male contact terminal  303  and the outgoing side wires  313  against the top end of the side male contact terminals  304 , creating electrical connections. Optionally, the wires  305 ,  313  may be soldered to the top ends of the terminals  303 ,  304 . The bottom ends of the contact terminals  303 ,  304  will make contact with corresponding conductors (i.e., movable side safety contacts  317 , movable center safety contact  318 ) on the multi-conductor female safety connector  302 . The male connector is held together with screws and attached inside the trunk body  300  by securing indentations  321 . Alternatively, the multi-conductor male safety connector  301  may be formed as a single piece with no screws, or as a snap-together assembly. One of ordinary skill in the art would recognize there are a variety of ways to form both the multi-conductor male connector  301  and the multi-conductor female safety connectors  302 . 
     Referring now to the female electrical connector  302  in  FIG. 3A , a fixed center terminal  309  is soldered to an incoming center wire  311  or held in electrical contact with an incoming center wire  311  by the female wire insulator  312 . The incoming side wires  314  pass through the female wire insulator  312  and into the female terminal insulator  315 , where they make an electrical connection, with or without soldering, with the fixed side terminals  310  embedded in the female terminal insulator  315 . These fixed side terminals  310  and fixed center terminal  309  are folded in a hook shape with the ends embedded in the insulators  312 ,  315 , exposing contact surfaces to air spaces  316 . The fixed side terminals  310  and fixed center terminal  309  are situated in close proximity to the corresponding movable side safety contacts  317  and movable center safety contact  318  respectively. 
     According to an embodiment of the present invention, one end of the movable center safety contact  318  is fixed to the female wire insulator  312 , and the other end hangs free, extending into an air space  316  in the female terminal insulator  315  above it. The free-hanging end is exposed to the open air, but recessed into the air space  316  in the exposed surface of the female terminal insulator  315 . The movable center safety contact  318  is made of a resilient flexible conductor which bends under force and returns to its original position when the force is removed. When the multi-conductor male safety connector  301  connects to the multi-conductor female safety connector  302 , as shown in  FIG. 3B , the center male contact terminal  303  presses against the movable center safety contact  318 , moving the free hanging end into electrical contact with the fixed center terminal  309 . 
     Both the movable center safety contact  318  and the movable side safety contact need to be pressed down at the same time in order to complete the circuit and make a connection which provides for safety from most accidental insertion of foreign bodies into the female socket. 
     The movable side safety contacts  317  are arranged corresponding to their fixed side terminals  310  in much the same manner as described above. One end of each movable side safety contact  317  is fixed in place and held between the safety terminal insulator  319  and the female securing insulator  320 . The other end floats freely, exposed in the adjacent air space  316 . The entire multi-conductor female safety connector  302  assembly is held together with screw  308  and attached inside the trunk body  300  by securing indentations  321 . Because the movable contacts  317 ,  318  are not in electrical contact with anything, they can be safely touched even when the trunk section  202  is powered. Looking now at  FIG. 3B , when the trunk sections  202  are assembled, the movable contacts  317 ,  318  are pressed into a position of electrical contact with the fixed terminals  309 ,  310 , passing power safely to the next trunk section. 
     According to an embodiment of the present invention, in order to prevent the multi-conductor male safety connector  301  being inserted too far, a limiting collar  325  is attached to the trunk body  300  at the appropriate distance. As shown in  FIG. 3B , when the safety connector is connected, this limiting collar, abuts the trunk body  300  of the other trunk section and prevents excess insertion. 
       FIG. 3C  shows the bottom view of the multi-conductor male safety connector  301 , and the top view of the multi-conductor female safety connector  302 . According to an embodiment of the present invention, the side terminals  304 ,  310  are arranged symmetrically and each side terminal  304 ,  310  corresponds to a separate circuit. In order to guarantee that the connectors  301 ,  302  are mated correctly, a key bar  322  on the body of the trunk section end with the multi-conductor male connector  301  slides into a key slot  323  cut into the body on the trunk section end with the female connector  302 . If the key bar  322  and key slot  323  are not aligned, the trunk sections will not slide together. The key bar  322  and key slot  323  are also shown in the cutaway view of  FIG. 3A-3B . One of ordinary skill in the art would recognize that the keying mechanism  322 ,  323  can be arranged in any way either on the trunk body  300  or on the male and female multi-conductor safety connectors  301 ,  302 . 
     According to an embodiment of the present invention, it is also possible to have a safety connector without accommodating multiple circuits, as depicted in  FIG. 3D-3E . In  FIG. 3D , the side male contact terminal  304  is a cylindrical ring  324 . This cylindrical ring can make contact with the movable side safety contacts  317  of the multi-conductor female safety connector  302  in any rotational orientation. Since rotational orientation is not important in this particular embodiment, there is no need for a keying mechanism in  FIG. 3D-3E . Because the movable side safety contacts  317  will both contact the same cylindrical ring  324 , the side contacts  317  become redundant, making the connection more reliable and able to accommodate more power. 
     According to an embodiment of the present invention depicted in  FIG. 3D-3E , the trunk body  300  has bare metal surfaces  326  where the two trunk sections connect. This allows a direct electrical connection to between the conductive walls of the trunk sections when the pieces are fitted together. This not only eliminates the need for a separate grounding pin, as depicted in  FIG. 4 , but also produces a more reliable ground throughout the entire tree trunk so long as the contact areas are kept clean and free of corrosion. This direct electrical connection can be accomplished in a variety of ways, including, but not limited to a conductive paint, a conductive sleeve, or pattern of conductive traces. One of ordinary skill in the art would recognize that there are many ways to accomplish this direct electrical connection without departing from the spirit of the present invention. 
       FIG. 4  shows two-prong male  401  and female  402  connectors mounted inside the trunk sections  400 . According to an embodiment of the present invention, a female ground clip  403  and a male ground pin  404  are spot welded  405  to their respective trunk sections. The trunk sections each have a flat side  406  that must be aligned with each other as a keying mechanism to ensure a properly grounded electrical connection. Another embodiment of the two-prong electrical connector incorporated into the tree is depicted in  FIG. 7B . One of ordinary skill in the art would recognize that just about any type of electrical connector, of a combination of connectors could be used here to achieve proper grounding, while routing power where it is needed. 
       FIG. 5  represents a cutaway side view and a face view of the side electrical connector mentioned earlier in  FIG. 1  (reference number  107 ) and  FIG. 2  (reference number  207 ). According to an embodiment of the present invention, the side view electrical connector  502  contains multiple conductors  503  for powering multiple independent circuits simultaneously. With multiple circuits running through independent conductors, the user has the option of using both AC and DC voltages and a variety of different voltage levels simultaneously, including but not limited to 3 VDC, 5 VDC, 12 VDC, 24 VDC, 36 VDC, 120 VAC, 230 VAC, 50 Hz AC, or 60 Hz AC. In this particular embodiment of the present invention, the side view electrical connector  502  snaps into the trunk body  501  by means of a securing tab  504 . One of ordinary skill in the art would recognize that such a sophisticated connector is not necessary. The task of routing power from inside the tree to outside the tree could also be accomplished with something as simple as a wire, electrically connected to the wires  103 ,  104  inside the tree, and passing through a hole in the trunk body. The connection could be either hard-wired or detachable. Another embodiment of a side connector incorporated into the tree is shown in  FIG. 7B . 
       FIG. 6  shows the inside of the foot pedal  600  that can be used to control the lighting on the tree. According to an embodiment of the present invention, the foot pedal ground wire  601  passes straight through the food pedal, while the foot pedal hot wire  602  and the foot pedal neutral wire  603  both pass through fuses  604  mounted in fuse holders  605  within the pedal  600 . The foot pedal hot wire also passes through a pushbutton  606  which can be used to turn the lights on and off or control the lighting mode. Although only one fuse is necessary, on the foot pedal hot wire  602 , extension cords that do not have a ground conductor would prevent proper grounding, and the distinction between the foot pedal hot wire  602  and the foot pedal neutral wire  603  would become arbitrary. The fuse on the foot pedal neutral wire  603  provides an additional level of protection in case the foot pedal ground wire  601  is not properly grounded. 
       FIG. 7  shows another embodiment of the entire tree  700  with two-prong electrical connectors, depicted in  FIG. 7A , connecting the trunk sections. The trunk body  702  has a conductive wall and is held upright by the base  701 . The two-prong electrical connector ground wire  704  is electrically connected to the conductive wall of the tree. The two-prong electrical connector hot wire  708  passes through a fuse in the fuse box  709 . Alternatively, fuses may be housed inside the foot pedal  771 . 
     Referring to  FIG. 7B , the two-prong electrical connector side electrical connector  714  provides access to the two-prong electrical connector hot wire  708  and the two-prong electrical connector neutral wire  703  from outside the tree. This two-prong electrical connector side electrical connector  714  may be a polarized or non-polarized two-prong electrical connector or any kind of electrical connector that accomplishes the purpose of routing power from inside the tree to outside the tree. One of ordinary skill in the art would recognize there are a variety of ways to implement the two-prong electrical connector side electrical connector  714 . The three-prong plug  110  allows for proper grounding when plugged into a grounded power outlet. An optional foot-pedal  771  allows for controlling the lights. In other embodiments, the control of the lighting of the tree may be controlled by one or more control elements, such as a switch, a selector knob, an indicator panel, or any other human interface device (HID) or any combination thereof. One of ordinary skill in the art would appreciate that there are numerous types of control elements that could be utilized with embodiments of the present invention, and embodiments of the present invention are contemplated for use with any type of control element. 
     In  FIG. 7A , the male electrical connector  712  connects to the female electrical connector  713  inside the trunk body  702  of the tree. 
     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from this detailed description. The invention is capable of myriad modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature and not restrictive.