Abstract:
A portable stack lamp includes a base supported by a supporting device, such as an extensible tripod and a plurality of rolling wheels, two or more lamp units stacked up to form a stack-up lamp body mounted on said base, and a cover which is adapted to cover a top opening of the housing of the lamp unit having a handle affixed thereon. The portable stack lamp is arranged to provide 360 degrees illumination so as to produce luminous beams in all directions while the user is able to selectively increase or decrease its luminous intensity by simply stacking up more or less lamp unit easily anytime. Therefore, the portable stack lamp can illuminate the surrounding that not only minimizes the number of work lamps to be used but also saves both the electrical energy and illumination cost. Moreover, each of the lamp unit of the portable stack lamp is arranged to equip a ring type fluorescent bulb as a light source so that it can be used indoor while consuming less electrical energy than the incandescent bulb or halogen bulb of the conventional work lamp.

Description:
BACKGROUND OF THE PRESENT INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The present invention relates to work lamps, and more particularly to a portable stack lamp which not only provides 360 degrees illumination but also is capable of being stacked up to increase lighting intensity.  
           [0003]    2. Description of Related Arts  
           [0004]    Table lamp, floor lamp, ceiling lamp, and etc. are common types of indoor lighting fixtures. Lantern lamp and spot light are outdoor lighting fixtures that generally use incandescent bulbs and halogen bulbs for illumination. Therefore, these outdoor lamps are most usually used as work lamps to provide supplemental illumination in working environments such as auto shops and factories.  
           [0005]    Portability is the primary feature of a work lamp so that it is handy for the user to carry elsewhere for use. Therefore, both the lantern lamp and spot lamp are compact in size for easy carry from place to place. However, the user must hand carry the work lamp or hang it up near the workplace for illumination.  
           [0006]    The luminous intensity of the conventional work lamp is limited to the power of light bulb. If a 60-watt incandescent bulb or halogen bulb is used in the lantern lamp or spot lamp, there is no way to increase or decrease the luminous intensity unless replacing the light bulb with one having a higher or lower watt.  
           [0007]    Since reflection disc is generally mounted behind the light bulb of the convention work lamp to reflect light beam to enhance luminous intensity, either the lantern lamp or the spot lamp can only emit luminous beam in a single direction that may limit the work lamp&#39;s application and require the user to rotate the entire work lamp by hand to direct the light beam to the area where the user wants to illuminate.  
           [0008]    Due to the safety concern that the halogen work lamp produces great amount of heat during illumination, it not only wastes energy but also renders the halogen work lamp not being allowed to be used indoor.  
         SUMMARY OF THE PRESENT INVENTION  
         [0009]    It is a main object of the present invention to provide a portable stack lamp which is arranged to provide 360 degrees illumination so as to produce luminous beams in all directions. Therefore, one portable stack lamp can illuminate the surrounding that not only minimizes the number of work lamps to be used but also saves both the electrical energy and illumination cost.  
           [0010]    It is another object of the present invention to provide a portable stack lamp which arrangement successfully equips a ring type fluorescent bulb as the light source in each lamp unit so that it can be used indoor while consuming less electrical energy than the incandescent bulb or halogen bulb of the conventional work lamp.  
           [0011]    It is another object of the present invention to provide a portable stack lamp wherein the circular central lamp mount which is used to support the ring type fluorescent bulb therearound is used, at the same time, as a reflective ring to reflect all light beams radially outwards.  
           [0012]    It is another object of the present invention to provide a portable stack lamp which enables the user to selectively increase or decrease its luminous intensity by simply stacking up more or less lamp unit easily anytime.  
           [0013]    It is another object of the present invention to provide a portable stack lamp which fluorescent bulb is arranged to be easily reached and replaced, wherein the user has no need to detach all upper lamp units one by one and merely requires to unassemble the lamp unit attached on top of the lamp unit to be repaired in order to reach the fluorescent bulb therein.  
           [0014]    It is another object oft he present invention to provide a portable stack lamp which can stand on floor, support at an adjustable height and is easy to carry and roll from place to place effortlessly.  
           [0015]    In order to accomplish the above objects, the present invention provides a portable stack lamp, comprising:  
           [0016]    a base having a top mounting surface and a bottom supporting surface;  
           [0017]    means for supporting the base being detachably attached to the bottom supporting surface of the base;  
           [0018]    at least a lamp unit which comprises:  
           [0019]    a housing which is a circular disc having a bottom wall and a surrounding wall made of transparent material;  
           [0020]    a ring-shaped lamp mount, which is attached to a central portion of the bottom wall of the housing, having a circular outer light reflective surface and defining a receiving chamber therein and a light source chamber between the light reflective surface and the surrounding wall of the housing;  
           [0021]    a ring type fluorescent bulb having a diameter smaller than the housing and larger than the lamp mount and a height smaller than the surrounding wall of the housing;  
           [0022]    means for mounting the fluorescent bulb around the lamp mount inside the light source chamber of the housing;  
           [0023]    a control circuit, which is disposed in the receiving chamber, comprising a power connector detachably connected to the fluorescent bulb, a power input terminal for electrically connecting to a power source to supply electricity to the fluorescent bulb, and a power output terminal for extended electrical connection;  
           [0024]    a bottom attachment fastener provided at a bottom portion of the housing; and  
           [0025]    a top attachment fastener provided at a top portion of the housing; and  
           [0026]    a cover adapted to cover a top opening of the housing of the lamp unit;  
           [0027]    wherein when only one lamp unit is used, the bottom attachment fastener thereof is attached to the top mounting surface of the base and the top attachment fastener is attached to the cover;  
           [0028]    in which when two more lamp units are used, the bottom attachment fastener of the bottom layer of lamp unit is attached to the top mounting surface of the base and the bottom attachment fastener of an upper layer of lamp unit is detachably fastened to the top attachment fastener of the lower neighboring layer of lamp unit so as to stack up the lamp units in a layer on layer manner, wherein the cover is attached to the top attachment fastener of the topmost layer of lamp unit to construct the portable stack lamp of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a perspective view of a portable stack lamp according to a preferred embodiment of the present invention.  
         [0030]    [0030]FIG. 2 is an exploded perspective view of the portable stack lamp according to the above preferred embodiment of the present invention.  
         [0031]    [0031]FIG. 3 is a perspective view of the portable stack lamp illustrating the top layer of lamp unit and the cover separately according to the above preferred embodiment of the present invention.  
         [0032]    [0032]FIG. 4 is a perspective view of the portable stack lamp illustrating how to replace the fluorescent bulb of a bottom layer of lamp unit according to the above preferred embodiment of the present invention.  
         [0033]    [0033]FIG. 5 is top perspective view of the lamp unit of the portable stack lamp according to the above preferred embodiment of the present invention.  
         [0034]    [0034]FIG. 6 is a bottom perspective view of the portable stack lamp according to the above preferred embodiment of the present invention, wherein the rolling wheels are replaced with floor stands.  
         [0035]    [0035]FIG. 7 is a perspective of the portable stack lamp according to an alternative mode of the above preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0036]    Referring to FIGS.  1  to  7 , a portable stack lamp according to a preferred embodiment of the present invention is illustrated, which comprises a base  10 , a cover  20  and one or more layers of lamp unit  30  mounted between the base  10  and the cover  20 .  
         [0037]    As shown in FIGS. 1, 2,  4 , and  6 , the base  10  has a top mounting surface  11  and a bottom supporting surface  12 . The base  10  further provides with a base attachment fastener  13  which includes a plurality of arc-shape attachment slots  131  circularly and spacedly aligned on the base  10 . Each of the attachment slots  131  has an indention  132  formed along a middle portion of an outer elongated side thereof. The base  10  further comprises an elongaged electric cord  14  having one end connected with a terminal connector  141 , which is extended to mount on the top mounting surface  11  of the base, and another end connected with an electric plug  142  for connecting to a power supply.  
         [0038]    Referring to FIGS. 2, 4 and  5 , each of the lamp units  30  comprises a housing  31 , a ring-shaped lamp mount  32 , a light source  33 , a control circuit  34 , a bottom attachment fastener  35 , and a top attachment fastener  36 .  
         [0039]    The housing  31 , which is a plastic made transparent circular disc having a U-shaped cross section, has a bottom wall  311  and a surrounding wall  312 . The lamp mount  32  is a ring-shaped body which bottom end inwardly protruded a plurality of fastening lips  321  for fastening on a central portion of the bottom wall  311  of the housing  31  by screws so as to integrally and coaxially fasten the lamp mount  32  on the bottom wall  311 . The lamp mount  32  further comprises a plurality of holder heads  322  integrally and spacedly protruded on an upper portion of the outer peripheral surface of the lamp mount  32 . The lamp mount  32  has a circular outer light reflective surface  323  and defines a receiving chamber  324  therein and a light source chamber  37  between the light reflective surface  323  and the surrounding wall  312  of the housing  31 .  
         [0040]    The lamp unit  30  further comprises a mounting device  38  for supporting the light source  33  around the lamp mount  32  inside the light source chamber  37  of the housing  31 , so that the light beams emitted from the light source around the lamp mount  32  illuminate all directions through the surrounding wall  312  while the reflective surface  323  ensures all light beams being radially directed outwards.  
         [0041]    According to the preferred embodiment of the present invention, the light source  33  is embodied as a ring type fluorescent bulb having a diameter smaller than the housing  31  and larger than the lamp mount  32  and a height smaller than the surrounding wall  312  of the housing  31 . The mounting device  38  includes a plurality of U-shaped holder mounts  381  having one end connected to the holder heads  322  respectively. Therefore, the ring type fluorescent bulb  33  is supported by sitting on the holder mounts  381  and the U-shaped holder mounts  381  are fittingly clipped on the body of the fluorescent bulb  33  spacedly so as to evenly support the weight of the fluorescent bulb  33  within the light source chamber  37 . Accordingly, the ring type fluorescent bulb  33  is extended around the housing  31  and emits luminous beams outside in 360 degrees through circular surrounding wall  312 . At the same time, the luminous beams emits inwardly from the inner peripheral edge of the fluorescent bulb  33  are all reflected radially outwards by the reflective surface  323  of the lamp mount  32 .  
         [0042]    The control circuit  34  is disposed in the receiving chamber  324  and mounted on the bottom wall  311  of the housing for controlling the power supply and illumination of the fluorescent bulb  33 . The control circuit  34  of the preferred embodiment should include a power connector  341  detachably connected to a power input terminal  331  to supply power for the light source  33 , a power input terminal  342  for electrically connecting with the power source to supply electricity (as shown in FIG. 4), and a power output terminal  343  for providing an electrical connection with another lamp unit  30  (if any) of the stack lamp of the present invention (as shown in FIG. 5). For fluorescent bulb, the power connector  341  should include a starter to light up the fluorescent bulb  33 .  
         [0043]    As shown in FIGS. 2 and 4, the bottom attachment fastener  35  of each of the lamp units  30  is provided at a bottom portion of the housing  31  thereof. The bottom attachment fastener  35  includes a plurality of arc-shaped attachment ribs  351  integrally and downwardly protruded from the bottom wall  311  of the housing  31 . The arc-shaped attachment ribs  351  are spacedly aligned along a peripheral edge of the bottom wall. On each of the attachment ribs  351 , an engagement knob  352  is protruded from a middle portion of the outer surface thereof that defines an engagement gap  353  between the engagement knob  352  and the bottom edge of the surrounding wall  312 . In addition, a threaded hole  353  is formed adjacent to the engagement gap  353  on each of the attachment ribs  351 .  
         [0044]    As shown in FIG. 6, in order to mount a lamp unit  30  on the base  10  to function as bottom layer of lamp unit  30 , the user may simply insert the arc-shaped attachment ribs  351  of the lamp unit  30  through the a re-shaped attachment slots  131  respectively while aligning the engagement knobs  352  with the indentions  132 , wherein the length of the attachment slot  131  should be longer than that of the attachment rib  351 . After the engagement knobs  352  pass through the attachment slots  131 , the user can simply rotate the lamp unit  30  until the engagement knobs  352  are disaligned with the indentions  132  so as to engage the base  10  between the bottom wall  311  of the lamp unit  31  and the attachment knobs  352 . Of course, other connection methods, such as screwing, clipping and gluing, can be used to connect the lamp unit  30  to the base  10 . It is also worth to mention that, when the bottom wall  311  of the lamp unit  30  is constructed strong and rigid enough, the bottom wall  311  can be functioned as the base  10  of the stack lamp of the present invention too.  
         [0045]    As shown in FIGS. 2 and 4, the top attachment fastener  36  of each of the lamp units  30  is provided at a top portion of the housing  31  thereof. The top attachment fastener  36  has a plurality of L-shaped engagement slots  361  formed on a top side of the surrounding wall  312  of the housing  31 . Each of the engagement slots  361  has a vertical portion downwardly extended from a top edge of the surrounding wall  312  and a transversal portion horizontally extended from a bottom of the vertical portion on the surrounding wall  312  of the housing, so as to define an edge tongue  362  above the transversal portion of the respective engagement slot  361 , wherein the width of the engagement slot  361  is equal to or slightly smaller than a size of the engagement knob  352 .  
         [0046]    Therefore, in order to stack up a lamp unit  30  on top of another one coaxially, the user merely needs to overlappedly stack an upper lamp unit  30  on another lower lamp unit  30  while aligning the engagement knobs  352  with the engagement slots  361  respectively. The distance between two opposing attachment ribs  351  should be arranged to be slightly smaller than an inner diameter of the top rim of the surrounding wall  312 , so that the attachment ribs  351  can be inserted in the light source chamber  37 . Then, when the top edge of the surrounding wall  312  of the lower lamp unit  30  supports against the bottom wall  311  of the upper lamp unit  30 , the engagement knobs  352  are positioned at the bottom end of the vertical portions of the engagement slots  361  respectively. To lock the connection, the user merely needs to rotate the upper lamp unit  30  with respect to the lower lamp unit  30  to transversally drive the engagement knobs  352  into the transversal portions of the engagement slots  361  so that the edge tongues  362  of the top attachment fastener  36  of the lower lamp unit  30  are engaged between the engagement knobs  352  and the bottom wall  311  of the upper lamp unit  30  while the threaded holes  353  of the attachment ribs  351  are aligned at the vertical portions of the engagement slots  361  respectively. Therefore, in order to enhance the connection between the upper and lower lamp units  30 , a plurality of fastening screws  39  each having an enlarged head is screwed into the threaded holes  353  until the enlarged heads are pressed against the surrounding wall  312  of the lower lamp unit  30  so as to further fasten the attachment ribs  351  of the upper lamp unit  30  with the surrounding wall  312  of the lower lamp unit  30 .  
         [0047]    In order words, the lamp units  30  can thus be stacked up in a layer on layer manner to form a stack-up lamp body. It is worth that it would be an apparent alternative mode to replace the arrangements of the bottom attachment fastener  35  and the top attachment fastener  36  with each other.  
         [0048]    As shown in FIGS. 2 and 3, the cover  20  is adapted to cover a top opening  313  of the housing  31  of the topmost lamp unit  30 . According to the preferred embodiment of the present invention, the cover  20  also comprises a cover attachment fastener  21  which is constructed identical to the bottom attachment fastener  35  of each of the lamp unit  30 , so that the cover attachment fastener  21  can be fastened with the top attachment fastener  36  of any of the lamp units  30  like how the bottom attachment fastener  35  of the upper lamp unit  30  is connected with the top attachment fastener  36  of the lower lamp unit  30  as described above.  
         [0049]    The cover  20  is preferred to further include a handle  22  pivotally affixed thereon for the user to hand carry the stack lamp from place to place. A handle recess  23  is formed on the cover  20  to receive the handle  22  when it is folded down.  
         [0050]    When only one lamp unit  30  is used, the bottom attachment fastener  35  thereof is attached to the top mounting surface  11  of the base  10  as described above and the top attachment fastener  36  is connected to the cover attachment fastener  21  of the cover  20 .  
         [0051]    When two more lamp units  30  are used, as shown in FIGS.  1  to  5 , the bottom attachment fastener  35  of the bottom layer of lamp unit  30  is mounted on the top mounting surface  11  of the base  10  and the bottom attachment fastener  35  of an upper layer of lamp unit  30  is detachably fastened to the top attachment fastener  36  of the lower neighboring layer of lamp unit  30  so as to stack up the lamp units  30  in a layer on layer manner, wherein the cover  20  is attached to the top attachment fastener  36  of the topmost layer of lamp unit  30  to construct the portable stack lamp of the present invention as shown in FIG. 1.  
         [0052]    In view of above, the portable stack lamp of the present invention is arranged to enable a ring type fluorescent bulb  33  to be equipped as the light source in each lamp unit so that it can be used indoor while consuming less electrical energy than the incandescent bulb or halogen bulb of the conventional work lamp. Moreover, the circular central lamp mount which is used to support the ring type fluorescent bulb therearound is used, at the same time, as a reflective ring to reflect all light beams radially outwards.  
         [0053]    All lamp units  30  have the same structure, so that the user is free to select the number of lamp units  30  to purchase. When the user needs more luminous intensity, the user can simply stack more lamp units  30  up. When the user wants to reduce the luminous intensity, the user can detach the desired number of lamp units  30  easily anytime.  
         [0054]    When the fluorescent bulb  33  of any lamp unit  30  is broken, the user has no need to detach all upper lamp units one by one. The user of the present invention merely needs to unassemble the lamp unit  30  attached on top of the lamp unit  30  to be repaired in order to reach the fluorescent bulb  33  therein, as shown in FIG. 4.  
         [0055]    The portable stack lamp of the present invention further comprises a supporting device  40  for supporting the base  10 , which is detachably attached to the bottom supporting surface  12  of the base  10 . Referring to FIGS.  1  to  5 , for ease of transportation, the supporting device  40  includes a plurality of rolling wheels  41  affixed to the bottom supporting surface  12  of the base  10  so that the user can roll it from place to place effortless.  
         [0056]    As shown in FIG. 6, the rolling wheels  41  can be replaced with floor stands  42  which are firmly screwed to the bottom supporting surface  12  of the base  10  to steadily support the portable stack lamp on a slippery surface.  
         [0057]    As shown in FIG. 7, an alternative mode of the supporting device  40 ′ is illustrated, which includes an extensible tripod  43 ′ to stand the portable stack lamp on floor. The tripod  43 ′ comprises a foldable tripod base  431 ′ and an extensible post  432 ′ upwardly extended from the foldable tripod base  431 ′, wherein a top end of the extensible post  432 ′ is detachably fastened to the bottom supporting surface  12  of the base  10 , so that the user is capable of adjusting the illuminating height of the portable stack lamp.