Abstract:
A hand-held inspection lamp is described. The lamp includes a multi-pin receptacle capable of connecting to a cord carrying alternating current and, alternatively, a cord capable of carrying direct current. The pins of the receptacle are wired to appropriate hardware within the lamp such that the proper type of current is supplied to a bulb housed therein. Thus, if the lamp is configured for a bulb that utilizes AC current, the pin configuration of the receptacle and an AC power cord supply AC current directly to the bulb or a ballast. The DC power cord has pins configured to supply current to an inverter connected to the bulb or ballast through the receptacle. A similar, but converse, arrangement is provided for the lamp when designed to house a bulb that utilizes DC current.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to hand-held electric lamps, and in particular to hand-held inspection lamps with external electrical power supply.  
           [0002]    As used herein, the term inspection lamp encompasses general illumination lamps and lamps with various color filters to emit light in selected ranges of wavelength, including infrared, visible and ultraviolet. The particular lamps described in this specification are filtered to emit in the ultraviolet and/or blue ranges to cause a flourescent response from flourescent tracer dyes for leak detection, coating and surface flaw inspection, and LV curing.  
         BACKGROUND OF THE INVENTION  
         [0003]    Inspection lamps requiring external electrical power supply are usually designed to connect exclusively to an alternating current (AC) or to a direct current (DC) power source, but not interchangeably to either AC or DC. Inspection lamps designed to connect to a DC source are typically smaller light-weight portable with a power cord having alligator clips for connecting to battery terminal posts or a plug for an automobile lighter socket. The AC lamps are typically larger and heavier, and have a power cord terminating in a three-prong grounded plug for use with an AC line voltage outlet.  
         SUMMARY OF THE INVENTION  
         [0004]    The invention is directed to inspection or curing lamps which can be quickly configured to connect to either an AC outlet or a DC power source merely by changing to the appropriate power cord. The pin connections between the cords and lamp are adapted to connect or to by-pass certain internal circuitry within the lamp.  
           [0005]    One type of lamp, for example, may have an internal AC to DC power converter enabling it to supply direct current to the bulb, regardless of the source. Another type of lamp may have an internal DC to AC converter to supply line voltage AC to the lamp, or to a transformer or impedance ballast to produce a particular voltage, frequency or waveform for lamp operation. Either type of lamp, in accordance with this invention, will have at least two detachable power cords with a multi-pin connection to the lamp. The pin connector circuitry in the lamp will remain unchanged by the power cord selection, but the pin connector circuitry in the power cords vary in how they connect certain pin sockets to the power source.  
           [0006]    Typically, a power cord for AC line voltage has a three-prong grounded outlet plug. A power cord for DC typically has battery clips or a cigarette lighter plug. In this invention, a multi-pin plug at the opposite end of the power cord has the same number and configuration of pins in both the AC and DC cords, but the pin connections in the cord differs between the AC cord and the DC cords.  
           [0007]    Using this invention in a lamp where a tungsten-halogen incandescent bulb is intended to be powered by 12-volt direct current, for example, the pin connections in the AC power cord automatically route the AC line current to an AC to DC power converter within the lamp, while the pin connections in the DC cords automatically bypass the converter. Conversely, using the invention in a lamp where a high intensity discharge (HID) bulb is intended to be powered by high-voltage high-frequency alternating current, the pin connections in the DC power cords automatically route the DC current to a DC to AC power converter within the lamp, while the pin connections in the AC cords would automatically by-pass the converter and route the AC line current directly to a transformer/ballast device.  
           [0008]    Various internal circuitry and pin configurations can be used, depending in part upon whether a particular polarity is required. Several alternative configurations are described herein.  
           [0009]    In addition, there may be other novel features of the particular lamps described. The lamp with an AC-powered MDL light source has several safety features in its configuration. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0010]    [0010]FIG. 1 is a view of an inspection lamp according to the invention with an ac power cord.  
         [0011]    [0011]FIG. 2 is a view of the lamp of FIG. 1 with the filter holder removed.  
         [0012]    [0012]FIG. 3A is a schematic representation of an inspection lamp similar to the lamp of FIG. 1 except with a DC power cord.  
         [0013]    [0013]FIG. 3B is a schematic representation of an alternative form of DC power cord.  
         [0014]    [0014]FIG. 3C is a schematic representation of an AC power cord.  
         [0015]    [0015]FIG. 4A is a schematic representation of an alternative form of inspection lamp with a DC power cord.  
         [0016]    [0016]FIG. 4B is a schematic representation of an alternative form of DC power cord.  
         [0017]    [0017]FIG. 4C is a schematic representation of an AC power cord.  
         [0018]    [0018]FIG. 5A is an electrical schematic depiction of the lamp and AC power cord of FIG. 4C.  
         [0019]    [0019]FIG. 5B is a depiction of the pin socket connections on the power cord of FIG. 4C.  
         [0020]    [0020]FIG. 5C is an electrical schematic depiction of the lamp and DC power cord of FIG. 4A.  
         [0021]    [0021]FIG. 5D is a depiction of the pin socket connections on the power cord of FIG. 4A.  
         [0022]    [0022]FIG. 6 is a perspective view of a novel protective cover for a bulb and reflector assembly.  
         [0023]    [0023]FIG. 7 is a side view of the protective cover shown in FIG. 6.  
         [0024]    [0024]FIG. 8 is a perspective view of a second embodiment of the protective cover for a bulb and reflector assembly.  
         [0025]    [0025]FIG. 9 is a cross-sectional view of the embodiment shown in FIG. 8 taken along line  9 - 9 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    The invention is described herein as embodied in several lamps and cord configurations which allow the lamp to be powered by either AC or DC power sources. The most common power sources are 10 V/60 Hz AC power and 12 V DC power. 110 V/60 Hz is the prevalent outlet power in the United States, and 12 V DC is prevalent in automobiles and automobile batteries. The two lamp examples which follow are a lamp using an AC-powered HID bulb, and a lamp with a DC-powered tungsten-halogen bulb. While some alternatives are suggested in the following text, neither the specific examples or the suggested alternatives are intended to exhaustively describe all of the forms in which the invention can be embodied.  
       Example of Lamp with AC-powered HID Bulb  
       [0027]    [0027]FIGS. 1 and 2 depict an inspection lamp  10  for producing a fluorescent response from dye additives for detecting fluid leaks in large closed containers or circulating systems, or producing a fluorescent response from penetrating dyes in NDT inspection for surface flaws, or detecting voids or dis-uniformity in coatings. A lamp of this type may be used to scan relatively large surfaces at relatively long distances to produce a fluorescent response. To excite a small accumulation of fluorescent dye sufficiently to cause a fluorescent response under these conditions, the lamp must emit high radiant power in the dye&#39;s excitation band. For example, a lamp of this type used to detect the presence of a fluorescent material using a perylene fluorescent dye should emit high radiant power in the UV-A range between 340 and 380 nm to take advantage of the perylene response peak in that range. To create this high emittance, the inspection lamp  10  uses a micro-discharge halide light source (MDL) similar to that used in some automobile headlights, which provides a high level UV-A energy and has nearly instant start and restart capabilities. MDL sources of this type are available in commercially produced bulbs, such as a Phillips DUV-35W.  
         [0028]    These MDL bulbs require special transformer/ballasting equipment to provide a voltage and frequency higher than normal 110 V/60 Hz for continuous operation, and extremely high open-circuit voltage for instant restart when hot. In particular, this lamp  10  uses an electronic transformer/ballast device to convert line power to approximately 390 V, 400 Hz open circuit (ballasted to maintain 50-150 V during operation). Then to achieve hot restart, it uses an ignition booster to create an open circuit voltage of 24,000 V maintained for approximately a 1.2 second pulse until the discharge arc is established. These electronic devices are housed within the lamp  10  as described hereafter.  
         [0029]    Referring now to FIG. 1, the lamp  10  comprises an electronics housing  12  and a hand-held illumination unit  14 , connected by an electrical conduit  16 . The electronics housing has a carry handle  18 , with a post  20  that acts as a stand for the hand held unit when not in use. The pistol grip handle  22  of the hand-held unit has an aperture (not visible in the drawings) to fit over the post  20 . This post/stand arrangement is not new, and has been used by the applicants&#39; assignee for several years.  
         [0030]    Because of the high voltage of this ignition device (referring now to FIG. 3A), the ballast device  24  is kept in the electronics housing and the ignition device  26  is moved into the hand-held unit  14 . This eliminates the potential hazard of having 24,000 V across a conduit  16  that could have its shielding insulation compromised through wear.  
         [0031]    Referring now to FIG. 2, the hand-held unit has a pistol grip handle  22  attached to a bulb/reflector housing  28 . The pistol grip handle has an ON/OFF switch  30  that must be held in the ON position to supply power to the MDL bulb  32 . Inside the bulb/reflector housing  28  is a smooth surfaced aluminized reflector  34  contoured to produce a long focal length. Attached to the end of the bulb/reflector housing is a removable silicon rubber filter holder  36 , into which is inserted an appropriate light filter  38 .  
         [0032]    A bulb/reflector assembly may be provided as a single unit. Thus, the assembly may be installed and removed from the bulb/reflector housing as described below. The reflector is secured around the base of the bulb, the electrical contacts of the bulb extending through the reflector. The base of the bulb includes bayonet pins extending transversely from the long axis of the bulb, such that the bulb/reflector assembly may be pushed downwardly into a socket and rotated slightly to lock each bayonet pin into the closed side of a J-shaped channel provided in the socket.  
         [0033]    The reflector  34  is provided with an external collar  202 , through which a pair of apertures  204  are furnished, one of the apertures  204  being hidden in FIG. 2. A protective cover  206  is shown in FIGS. 6 and 7. The cover  206  is generally round, shaped to correspond with the opening of the reflector  34  and to cover the external collar  202 . Two tabs  208  protrude through the cover  206 , positioned to correspond with the apertures  204 . When a user opens the packaging of the reflector/bulb assembly, the cover is in place with tabs  208  engaging apertures  204 , thereby protecting the aluminized surface of the reflector  34 . The user may grasp a handle  210 , which is conveniently provided on the cover  206 . The bulb and reflector may then be inserted into the housing and secured into place via a twisting motion, without ever being touched by the user. Once the reflector is secured, a withdrawing motion forces the tabs  208  to disengage apertures  204 , allowing removal of the cover  206  from the reflector  34 .  
         [0034]    The protective cover may be formed from any material having suitable rigidity to support the necessary handling, inserting, and rotating actions described above. One acceptable material is rigid cardboard. A single piece of cardboard may be cut in a shape comprised of a rectangular center section  212  separated by fold lines  214  from semicircular ends  216 . A central fold line  218  is parallel with fold lines  214  and bisects the central portion  212 . Folding the single piece of cardboard along the three fold lines provides a round base, which has a circumference corresponding with the shape and size of the reflector collar  202 , and a handle  210  perpendicular thereto. Various designs of holes (not shown) may be provided in the handle  210  to facilitate grasping. Further, a fastener (not shown) may be provided to secure the two halves of the handle to one another and prevent unfolding of the cover.  
         [0035]    Another embodiment of the cover  220  is shown in FIGS. 8 and 9. This cover  220  may be formed from a single circular piece of rigid material, preferably cardboard. Two or more punch out tabs  222  are defined by lines of weakness  224  on three sides. The lines of weakness may be scored or die cut into the cover using any of the techniques well known to those skilled in the art. The fourth side of each punch out tab is left unscored such that the tabs do not become unattached when knocked out, thereby preventing them from falling into the reflector. The tabs are positioned such that an average user can insert fingers therethrough to grasp the cover. Caution must be used, however, in not putting fingers through so far as to contact the reflector or the bulb.  
         [0036]    The lamp  10  is supplied with at least two power cords. The power cord  40  in FIG. 1 has a three pronged grounded plug  42  on one end for connecting to an AC outlet. This type of plug is also shown schematically in FIG. 3C. The lamp is also supplied with at least one alternative power cord  50 , having a device for connection to a DC source, such as the battery terminal clips  52  of FIG. 3B or the lighter plug  54  of FIG. 3A. Regardless of the type of connection device on the end of the cord distal to the lamp, the proximal end of the cord has a multi-pin connector, herein a six-pin plug  44 A,  44 B. The electronics housing  12  has a corresponding receptacle  48  with six pins. Inside the plug, the pin sockets are wired to the power cord according to the type of power supply to be used.  
         [0037]    For instance, in the schematic of FIG. 3A, the power cord  50  is for a DC power supply from an automobile lighter. The plug  44 A is wired so that the positive DC contact will be connected to pin socket  1 . The negative contact is wired to pin socket  2 . Pin socket  3  is wired to pin socket  5 , and pin socket  4  is wired to pin socket  6 . The cord  50  shown in FIG. 3 b  is essentially the same as the cord in FIG. 3A, except that it has battery terminal clips  52  instead of the lighter plug  54 .  
         [0038]    Inside the electronics housing  12 , the receptacle pins corresponding to plug sockets  1  and  2  are wired to the input terminals of an inverter  58 , which takes in the 12 V DC and outputs 110 V, 60 Hz AC power. The output from the inverter  58  is routed through pins  3  and  4 , which are in turn connected back into the housing by pins  5  and  6 . Pins  5  and  6  are connected to an ON/OFF switch  60  on the electronics housing.  
         [0039]    Placing the manual switch  60  “ON” supplies 110 V, 60 Hz power to the electronic ballast and transformer device  24  described above to deliver 400 Hz AC at approximately 390 V open circuit (ballasted to maintain 50-150 V during operation) through conduit  16 . When the ON/OFF  30  switch is depressed, the ignition device  26  starts the MBL bulb&#39;s discharge arc and the lamp illuminates.  
         [0040]    The plug  44 B shown in FIG. 3C is for connecting the lamp to a 110 V AC outlet. In this plug, the ground terminal is wired to pin socket  2 . The AC power lines are wired to pin sockets  5  and  6 . Pins  5  and  6  then bypass the inverter and deliver 110 V, 60 Hz AC power directly to the transformer. Thereafter operation is as described above.  
       Example of Lamp with a DC-Powered Tungsten-Halogen Bulb  
       [0041]    [0041]FIG. 4A is an example of a smaller hand-help inspection lamp  100  that is intended for use at closer range and in more restricted space than the larger lamp described above. This type of lamp, for example, may be used to inspect for leaks in an automotive air conditioning system. Since the range is less, the lamp can produce a fluorescent response without needing as high intensity radiance from the light source. For increased maneuverability in tight compartments, the lamp is constructed in a compact style having a handle  102  in line with the bulb/reflector housing  104 . The handle encloses an AC to DC converter  106  and has a momentary ON/OFF switch  108 . This lamp uses a tungsten halogen bulb  110  that is designed for use with 12 V DC.  
         [0042]    At the end of the handle away from the bulb/reflector housing is a multi-pin receptacle, herein a six-pin receptacle  112 . The lamp of FIG. 4 a  has a power cord  114 A connected to the receptacle that has a plug  116  with six pin sockets at one end and a lighter plug  118  at the other end.  
         [0043]    As shown in FIGS. 5C and 5D, the plug  116  is wired so that the positive DC contact will be connected to pin socket  1 . The negative DC contact is wired to pin socket  5 . Pin socket  2  is wired to pin socket  6 . Pin sockets  3  and  4  are not connected. The cord  114 B shown in FIG. 4B is essentially the same as the cord  114 A in FIG. 4A, except that it has battery terminal clips  120  instead of the lighter plug  118 .  
         [0044]    Inside the lamp, as shown also in FIG. 5C, pin  1  is connected to one side of the momentary ON/OFF switch  108 . The other side of switch  108  brings DC voltage to the input of an AC to DC converter  106 , but bypasses the converter through pin  6  to pin  2 , and then to one terminal connection of the bulb. The other bulb terminal is connected to pin  5 , completing a DC circuit through bulb  110  when the switch is moved to the “ON” position. Pin  3  is connected to ground and pin  4  to the output of the AC/DC converter, but the respective sockets  3  and  4  are not connected in the DC cords.  
         [0045]    In the AC power cord of FIGS. 4C, 5A and  5 B, pin socket  1  is connected to the hi-side prong of the three-prong AC plug, pin socket  5  to the neutral prong, and pin socket  3  to the ground prong. Pin sockets  2  and  4  are connected together, and socket  6  is not connected. Inside the lamp the pin wiring remains unchanged. Pin  1  is wired to the ON/OFF switch  108 . When the switch is moved to ON, AC power is connected to the input side of the AC to DC converter  106 . 12 V DC power is then output from the converter through pin  4  out through the plug to pin  2  to a terminal connector of the bulb. The other bulb terminal is connected to the neutral pin  5 . Pin  3  connects the supply ground to the lamp ground.  
         [0046]    Other internal lamp configuration, with corresponding AC and DC power cords, can be used to accomplish the same result. Thus, the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.