Patent Publication Number: US-8541932-B2

Title: Lamp with heat dissipater

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a lamp and, more particularly, to a lamp including a hollow casing formed by a heat dissipater. 
     2. Description of the Related Art 
       FIG. 1  shows a conventional lamp  8  including a cooling body  81  with a plurality of fins  811  on an outer periphery thereof. A lighting element  82  is mounted to an end of the cooling body  81 . An electrically conductive member  83  is mounted to the other end of the cooling body  81  and electrically connected to the lighting element  82 . Through control by a control unit such as a circuit board, the lighting element  82  emits light beams after the electrically conductive member  83  is supplied with electricity. The cooling body  81  assists in dissipation of heat generated during operation of the lighting element  82  and the electrically conductive member  83 . 
     However, the cooling body  81  must be large enough to receive the lighting element  82  and the electrically conductive member  83  for cooling purposes, leading to a bulky cooling body  81  and causing inconvenience in usage. Furthermore, the lamp  8  does not include ventilation holes and cooling fans and, thus, can not provide excellent cooling effect. The overall cooling effect of the lamp  8  is thus not satisfactory, shortening the service life of the lighting element  82 . 
     To mitigate the disadvantages of the lamp  8 ,  FIG. 2  shows another conventional lamp  9  including a first housing  91 , a second housing  92 , a circuit board  93 , a cooling module  94 , and a lighting element  95 . The first housing  91  has a plurality of air inlets  911 . The second housing  92  has a plurality of air outlets  921 . The circuit board  93 , the cooling module  94 , and the lighting element  95  are mounted in a hollow casing formed by the first and second housing  91  and  92 . The cooling module  94  is comprised of a cooling fan  941  and a heat dissipater  942 . The circuit board  93  is electrically connected to the cooling fan  941  and the lighting element  95 . The lighting element  95  is connected to the heat dissipater  942 . 
     When the lighting element  95  is supplied with electricity and generates heat, the circuit board  93  drives the cooling fan  941  to rotate. Ambient air is driven in via the air inlets  911  and cooperates with the heat dissipater  942  to dissipate the heat generated by the lighting element  95 . Furthermore, the heat is carried away by the hot air that is driven out by the cooling fan  941  via the air outlets  921 , obtaining the predetermined cooling effect and prolonging the service life of the lighting element  95 . 
     However, the lamp  9  still has several disadvantages. Firstly, the hollow casing of the lamp  9  is comprised of the first and second housings  91  and  92  for receiving the circuit board  93 , the cooling module  94 , and the lighting element  95 . Thus, the lamp  9  has a complicated structure, and the assembly is inconvenient. Furthermore, the first and second housings  91  and  92  must be processed to form the air inlets  911  and the air outlets  921 , leading to inconvenience in manufacturing and high manufacturing costs. Secondly, the air inlets  911  and the air outlets  921  are arranged mainly to introduce ambient air to dissipate the lighting element  95 . The cooling effect is poor at the circuit board  93 . 
     Thus, a need exists for a lamp with improved cooling effect. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a lamp with simplified structure. 
     Another objective of the present invention is to provide a lamp that can be assembled easily. 
     A further objective of the present invention is to provide a lamp that provides excellent cooling effect. 
     The present invention fulfills the above objectives by providing, in a first aspect, a lamp including a heat dissipater having a base and an engaging member. The base includes a first air guiding portion and a fixing portion. The engaging member is mounted to an outer periphery of the base. A second air guiding portion is formed between the engaging member and the base. A lighting element is mounted to the base of the heat dissipater. A housing is engaged with the engaging member of the heat dissipater. The housing and the heat dissipater together define a compartment in communication with the first and second air guiding portions. A cooling fan is mounted to the fixing portion of the base. A circuit board is mounted in the compartment and electrically connected to the lighting element and the cooling fan. The circuit board is electrically connected to an electrically conductive member having an end extending out from the housing. 
     According to a second aspect, a lamp includes a heat dissipater having a base and an engaging member. The base includes a first air guiding portion and a fixing portion. The engaging member is mounted to an outer periphery of the base. A lighting element is mounted to the base of the heat dissipater. A housing is engaged with the engaging member of the heat dissipater. The housing includes a second air guiding portion. The housing and the heat dissipater together define a compartment in communication with the first and second air guiding portions. A cooling fan is mounted to the fixing portion of the base. A circuit board is mounted in the compartment and electrically connected to the lighting element and the cooling fan. The circuit board is electrically connected to an electrically conductive member having an end extending out from the housing. 
     The present invention will become clearer in light of the following detailed description of its illustrative embodiments described in connection with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiments may best be described by referring to the accompanying drawings where: 
         FIG. 1  shows a perspective view of a conventional lamp. 
         FIG. 2  shows a cross sectional view of another conventional lamp. 
         FIG. 3  shows an exploded, perspective view of a lamp of a first embodiment according to the preferred teachings of the present invention. 
         FIG. 4  shows a cross sectional view of the lamp of  FIG. 3  after assembly. 
         FIG. 5  shows a top view of a lamp of a modified embodiment according to the preferred teachings of the present invention. 
         FIG. 6  shows an exploded, perspective view of a lamp of a second embodiment according to the preferred teachings of the present invention. 
         FIG. 7  shows a cross sectional view of the lamp of  FIG. 6  after assembly. 
         FIG. 8  shows an exploded, perspective view of a lamp of a third embodiment according to the preferred teachings of the present invention. 
         FIG. 9  shows a cross sectional view of the lamp of  FIG. 8  after assembly. 
     
    
    
     All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiments will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions conforming to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood. 
     Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “inner”, “outer”, “side”, “end”, “portion”, “radial”, “annular”, and similar terms are used herein, it should be understood that these terms refer only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A cooling fan of a first embodiment according to the preferred teachings of the present invention is shown in  FIGS. 3 and 4  and generally includes a heat dissipater  1 , a lighting element  2 , a housing  3 , a cooling fan  4 , and a circuit board  5 . The heat dissipater  1  is engaged with the lighting element  2 . The housing  3  engages with the heat dissipater  1  to form a hollow casing for receiving the cooling fan  4  and the circuit board  5 . The cooling fan  4  is engaged and cooperates with the heat dissipater  1  to provide cooling effect for the lighting element  2 . The circuit board  5  is electrically connected to the cooling fan  4  for driving the cooling fan  4  to rotate. 
     The heat dissipater  1  includes a base  11  and an engaging member  12 . The base  11  includes a first air guiding portion  111  and a fixing portion  112 . The first air guiding portion  111  can be of any structure allowing passage of air into or out of the hollow casing. The first air guiding portion  111  can provide air inlet effect or air outlet effect according to the rotating direction of the cooling fan  4 . The fixing portion  112  can be of any structure allowing engagement with the cooling fan  4 . The engaging member  12  is mounted to an outer periphery of the base  11  with a second air guiding portion  121  formed between the engaging member  12  and the base  11 . The second air guiding portion  121  can be of any structure allowing passage of air into or out of the hollow casing. The second air guiding portion  121  can provide air inlet effect or air outlet effect according to the rotating direction of the cooling fan  4 . 
     In this embodiment, the base  11  includes a seat  11   a  and an annular wall  11   b  formed along an outer periphery of the seat  11   a . The first air guiding portion  111  is in the form of at least one passageway formed between an adjoining area between the seat  11   a  and the annular wall  11   b . The passageway of the first air guiding portion  111  serves as an air outlet. The fixing portion  112  includes a plurality of pegs formed on an inner periphery of the annular wall  11   b . Furthermore, the engaging member  12  includes an engaging ring  12   a  connected to the annular wall  11   b  by a plurality of connecting ribs  12   b . By such an arrangement, the second air guiding portion  121  is in the form of a plurality of passageways between the connecting ribs  12   b . The passageways of the second air guiding portion  121  serve as air inlets. In an alternative embodiment shown in  FIG. 5 , the engaging member  12  includes a plurality of protrusions  12   c  formed on an outer periphery of the annular wall  11   b , and the second air guiding portion  121  includes a plurality of passageways formed between the protrusions  12   c  and serving as air inlets. 
     The lighting element  2  is mounted to the base  11  of the heat dissipater  1 . The lighting element  2  can be a light-emitting diode (LED), a bulb, or any other member that can emit light beams when supplied with electricity. In this embodiment, the lighting element  2  is mounted to a side of the seat  11   a  of the heat dissipater  1 . 
     The housing  3  is engaged with the engaging member  12  of the heat dissipater  1 . The hollow casing formed by housing  3  and the heat dissipater  1  includes a compartment  31  ( FIG. 4 ) in communication with the first and second air guiding portions  111  and  121 . In this embodiment, the housing  3  is a hollow semi-sphere and includes an opening  32  in an end thereof. A through-hole  33  is formed in the other end of the housing  3 . An end edge of the housing  3  having the opening  32  is fixed to the engaging ring  12   a  by suitable provisions such as welding, bonding, locking, male/female coupling, etc. 
     The cooling fan  4  is mounted to the fixing portion  112  of the base  11  and aligned with the first air guiding portion  111 . In this embodiment, the cooling fan  4  includes a fan housing  41  in which a fan wheel  42  is rotatably received. The fan housing  41  can be fixed by a plurality of fasteners  43  (such as screws or the like) to the fixing portion  112  (the pegs). Thus, the fan housing  41  is securely fixed to the base  11 . Furthermore, the fan housing  41  can include a block portion  411  engaged with the base  11 . The block portion  411  prevents reverse flow of air currents flowing through the first air guiding portion  111 . 
     The circuit board  5  is mounted in the compartment  31  and electrically connected to the lighting element  2  and the cooling fan  4  for controlling the lighting element  2  and for driving the fan wheel  42  of the cooling fan  4  to rotate. The circuit board  5  also includes an electrically conductive member  51  that has an end exposed outside of the housing  3 . In this embodiment, the end of the electrically conductive member  51  of the circuit board  5  extends out from the housing  3  via the through-hole  33  of the housing  3 . 
     In use of the lamp according to the preferred teachings of the present invention, the lamp can be mounted to a lamp seat on a wall, ceiling, or desk. The lamp is electrically connected to an electricity service system via the electrically conductive member  51  such that the lighting element  2  can emit light beams when supplied with electricity. The electricity service system also provides power to the cooling fan  4  for operation. With the arrangement of the first and second air guiding portions  111  and  121  in communication with the compartment  31  receiving the circuit board  5 , and by the engagement between the lighting element  2  and the heat dissipater  1 , the first and second air guiding portions  111  and  121  cooperate with the cooling fan  4  to provide excellent cooling effect for the lighting element  2  and the circuit board  5  when the lighting element  2  and the circuit board  5  are supplied with electricity and generate heat. 
     Specifically, with reference to  FIG. 4 , when the circuit board  5  drives the fan wheel  42  of the cooling fan  4  to rotate, the fan wheel  42  drives air currents into the compartment  31  via the second air guiding portion  121  to dissipate the heat generated by the circuit board  5 . Furthermore, the heat dissipater  1  transmits the heat generated by the lighting element  2  supplied with electricity, and the fan wheel  42  guides the air currents out via the first air guiding portion  111 . The heat of the heat sources is thus transmitted to the outside, obtaining better cooling effect and prolonging the service life of the lighting element  2 . 
       FIGS. 6 and 7  show a lamp of a second embodiment according to the preferred teachings of the present invention. The lamp also includes a heat dissipater  1 ′, a lighting element  2 , a housing  3 ′, a cooling fan  4 , and a circuit board  5 . The lighting element  2 , the cooling fan  4  and the circuit board  5  in this embodiment are substantially the same as those in the first embodiment except for minor modification to the outlines, and are thus not described in details to avoid redundancy. 
     The main difference between the heat dissipater  1 ′ of the second embodiment and the heat dissipater  1  of the first embodiment is that the first air guiding portion  111  of the heat dissipater  1 ′ is in the form of at least one passageway formed in a central portion of the seat  11   a , and that the heat dissipater  1 ′ of the second embodiment does not include the second air guiding portion  121  of the first embodiment. Furthermore, the housing  3 ′ of the second embodiment includes a second air guiding portion  34  in communication with the compartment  31 . In the second embodiment, the second air guiding portion  34  includes a plurality of passageways extending through the housing  3 ′ and serving as air inlets. With reference to  FIG. 7 , when the fan wheel  42  of the cooling fan  4  rotates, the fan wheel  42  drives air currents into the compartment  31  via the second air guiding portion  34  to transmit the heat generated by the circuit board  5  and the lighting element  2  to the outside via the first air guiding portion  111 , obtaining better cooling effect and prolonging the service life of the lighting element  2 . 
       FIGS. 8 and 9  show a lamp of a third embodiment according to the preferred teachings of the present invention. The lamp also includes a heat dissipater  1 ″, a lighting element  2 , a housing  3 , a cooling fan  4 , and a circuit board  5 . The lighting element  2 , the housing  3 , the cooling fan  4 , and the circuit board  5  in this embodiment are substantially the same as those in the first embodiment and are thus not described in details to avoid redundancy. 
     The main difference between the heat dissipater  1 ″ of the third embodiment and the heat dissipater  1  of the first embodiment is that the first air guiding portion  111  of the heat dissipater  1 ″ is in the form of at least one passageway formed in a central portion of the seat  11   a . Furthermore, the engaging member  12  includes a flange  12   d , and a plurality of support blocks  12   e  extends from an outer surface of the flange  12   d . The end edge of the opening  32  of the housing  3  is fixed to the support blocks  12   e  of the engaging member  12 . Thus, the second air guiding portion is in the form of a plurality of radial passageways formed between the support blocks  12   e  and serving as air inlets. With reference to  FIG. 9 , when the fan wheel  42  of the cooling fan  4  rotates, the fan wheel  42  drives air currents into the compartment  31  via the second air guiding portion  121  to transmit the heat generated by the circuit board  5  and the lighting element  2  to the outside via the first air guiding portion  111 , obtaining better cooling effect and prolonging the service life of the lighting element  2 . 
     An arcuate guide face F can be formed in an adjoining area between the flange  12   d  of the engaging member  12  and the annular wall  11   b  of the base  11  to provide an air guiding effect. 
     In view of the foregoing, the lamp according to the preferred teachings of the present invention is simple in structure. Specifically, the compartment  31  receiving the lighting element  2 , the cooling fan  4 , and the circuit board  5  is defined by the heat dissipater  1 ,  1 ′,  1 ″ and the housing  3 ,  3 ′ through provision of the engaging member  12  of the heat dissipater  1 ,  1 ′,  1 ″. Compared to the hollow casing comprised of the first and second housings  91  and  92  of the lamp  9  shown in  FIG. 2 , one of the first and second housings  91  and  92  is replaced with the heat dissipater  1 ,  1 ′,  1 ″ in the lamp according to the preferred teachings of the present invention. Thus, the whole structure is simplified and allows convenient manufacturing. Furthermore, the assembly of the lamp according to the preferred teachings of the present invention can be achieved easily by engaging the lighting element  2  and the cooling fan  4  with the heat dissipater  1 ,  1 ′,  1 ″, mounting the circuit board  5  to the housing  3 ,  3 ′, and engaging the housing  3  with the heat dissipater  1 ,  1 ′,  1 ″. Convenient assembly is thus provided. 
     With the arrangement of the first air guiding portion  111  and the second air guiding portions  121  and  34  in communication with the compartment  31  receiving the circuit board  5  and the engagement between the lighting element  2  and the heat dissipater  1 ,  1 ′,  1 ″, the cooling fan  4  drives air current to flow through the first air guiding portion  111  and the second air guiding portions  121  and  34  to provide excellent cooling effect for the lighting element  2  and the circuit board  5 , enhancing the cooling effect. 
     Thus, since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.