Patent Publication Number: US-7914183-B2

Title: LED lamp having elastic members for securing LED module to heat sink thereof

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to an LED lamp, and particularly to an LED lamp having an LED module readily secured to a heat sink of the LED lamp. 
     2. Description of Related Art 
     An LED lamp is a type of solid-state lighting device that utilizes light-emitting diodes (LEDs) as a source of illumination. The LED has an advantage of being resistant to shock, and an almost unlimited lifetime under specific conditions, making it a cost-effective yet high quality replacement for incandescent and fluorescent lamps. Conventionally, the LED lamp utilizes a heat sink to dissipate heat generated by the LED module. The LED module is directly secured to the heat sink by a mounting device such as a plurality of fasteners. The assembly of the plurality of the fasteners is the source of some difficulty, since the fasteners may drop from the LED module during assembly, a problem that is aggravated when the LED lamp is deployed outdoors and at heights, such as when the LED lamp is a highway lamp. 
     What is needed, therefore, is an improved LED lamp which can overcome the described limitations. 
     SUMMARY OF THE DISCLOSURE 
     An LED lamp includes an LED module, a heat sink having a base abutting an upside of the LED module, a plurality of posts extending through the LED module and into the base of the heat sink, and a plurality of elastic members engaging the plurality of posts respectively and elastically abutting an underside of the LED module to secure the LED module to the base of the heat sink. The LED module is sandwiched between the base and the elastic members. 
     Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric, exploded view of an LED lamp in accordance with a preferred embodiment of the present disclosure. 
         FIG. 2  is an inverted view of the LED lamp in  FIG. 1 . 
         FIG. 3  is a cross-section of the LED lamp in  FIG. 1 , showing posts and elastic members engaging a heat sink of the LED lamp. 
         FIG. 4  is a view similar to  FIG. 3 , but shows the LED module disposed among the posts and the elastic members. 
         FIG. 5  is a view similar to  FIG. 3 , but shows the LED module and the posts combined together by the elastic members. 
         FIG. 6  is an assembled view of the LED lamp in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Referring to  FIGS. 1-2 , an LED lamp  100  in accordance with a present embodiment is illustrated. The LED lamp  100  comprises a heat sink  10 , an LED module  40  located on the heat sink  10 , and a mounting device (not labeled) securing the LED module  40  to the heat sink  10 . The mounting device includes four posts  20  engaging the heat sink  10  and extending through the LED module  40 , and four elastic members  30  mounted on the posts  20 . The LED module  40  is sandwiched between the heat sink  10  and the elastic members  30 . 
     Also referring to  FIG. 3 , the heat sink  10  comprises a rectangular base  12  and a plurality of fins  14  extending therefrom. The base  12  has a top surface  16  and a bottom surface  18  opposite thereto. The fins  14  extend parallel and upwardly from the top surface  16  of the base  12 . A rectangular recess  15  is defined in the bottom surface  18  of the base  12  and adjoins edges of the base  12 , for receiving a waterproof cushion (not shown) therein, whereby a transparent/translucent cover (not shown) of the LED lamp  100  can be hermetically mounted to the bottom surface of the base  12  to protect the LED module  40  therein. The base  12  defines four fastener holes  19  in the bottom surface  18  thereof engaging the posts  20 . The four fastener holes  19  are within the recess  15 . 
     Each of the posts  20  comprises a head portion  22 , a neck portion  24 , a pole portion  26 , and a threaded portion  28  extending from the pole portion  26 . The head portion  22 , the neck portion  24 , the pole portion  26  and the threaded portion  28  align on a same longitudinal axis. The neck portion  24  extends from the head portion  22  and has a diameter less than that of the head portion  22 . The pole portion  26  extends from the neck portion  24  and has the same diameter as the head portion  22 . The threaded portion  28  forms a spiral thread on an outer wall thereof. Each of the threaded portions  28  engages each of the fastener holes  19  of the base  12  so that the posts  20  are secured to the heat sink  10 . Due to the diameter of the neck portion  24  being less than that of the head portion  22  and the pole portion  26 , a round recess is defined around an outer surface of the neck portion  24 , receiving the elastic member  30 . 
     Each elastic member  30  is of an elastic material such as rubber. In this embodiment, each elastic member  30  is a rubber ring with a central hole  32  defined therein. A thickness of each elastic member  30  is similar to a length of the neck portion  24  along the axial direction thereof. Outer diameters of each elastic member  30  gradually decrease along the axial direction from a middle portion thereof to two ends of the elastic member  30 . Thus, the elastic member  30  has a convex outer circumferential surface. In an original shape, an inner diameter of each elastic member  30  (i.e., a diameter of the central hole  32 ) is smaller than the diameter of the head portion  22 ; and the outer diameter of each end of the elastic member  30  is the same as the diameter of the head portion  22 , whereby the outer diameter of middle portion of the elastic member  30  is larger than that of the head portion  22 . The elastic member  30  can be elastically expanded in a radial direction when an expanding force in the radial direction is applied thereto, so that the head portions  22  of the posts  20  are able to extend through the central holes  32  of the elastic members  30 , whereby the neck portions  24  of the posts  20  engage in the central holes  32 , respectively. 
     The LED module  40  comprises a substantially square circuit board  41  and a plurality of LEDs  45  arranged on an underside (not labeled) of the circuit board  41  in a matrix. Corresponding to the four fastener holes  19  in the base  12 , four through holes  49  are defined in the circuit board  41 . Each of the through holes  49  has an inner diameter slightly larger than the diameter of the head portion  22  of each post  20  and smaller than the outer diameter of the middle portion of the elastic member  30 . 
     As shown in  FIGS. 3-6 , in assembly of the LED lamp  100 , each of the elastic members  30  is mounted to the neck portion  24  of each post  20  via the head portion  22  extending through the central hole  32  of the elastic member  30 . The elastic member  30  is received in the recess of the post  20  and two ends thereof abut the head portion  22  and the pole portion  26 , respectively. The threaded portion  28  of each of the posts  20  engages the fastener hole  19  of the base  12  with the pole portion  26  abutting the base  12 . The LED module  40  is mounted to the posts  20  engaged in the base  12  with the through holes  49  of the circuit board  41  correspondingly sleeving the head portions  22  of each post  20 . Each of the elastic members  30  is pressed by the circuit board  41  of the LED module  40  and has an inwardly elastic deformation to extend through the through holes  49  of the circuit board  41 . The circuit board  41  of the LED module  40  is impelled to engage the pole portions  26  of the posts  20 , and releases the elastic members  30  to resume the original shape. The base  12  abuts an upside of the circuit board  41  of the LED module  40  and the elastic members  30  elastically abut an underside of the LED module, whereby the circuit board  41  of the LED module  40  is securely sandwiched between the base  12  and the elastic members  30 . Accordingly, the circuit board  41  of the LED module  40  is securely attached to the base  12  of the heat sink  10  by the elastic members  30 . 
     In disassembly of the LED lamp  100 , the LED module  40  is directly withdrawn from base  12  of the heat sink and passes through the posts  20  and the elastic members  30  via the elastic deformation of the elastic members  30 . Additionally, since the posts  20  with the elastic members  30  are pre-assembled to the base  12  of the heat sink  10 , assembly the LED module  40  to the heat sink  10  is convenient. 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.