Abstract:
The present invention discloses a lamp, mounted on a socket when in use, comprising a cap, a housing, and a light source, wherein the cap is adapted to connect to the socket, one of the cap and the housing comprises a tubular body, and the other comprises a cylindrical cavity for accommodating the tubular body, and the tubular body rotates in the cylindrical cavity around an axis of the cap and moves along the axial direction of the cap to effect relative rotation and relative telescopic motion between the cap and the housing. The lamp of the present invention allows both relative rotation and relative telescopic motion between the cap and the housing, therefore facilitating adjustment of the illumination direction, and is adaptable to different types of fittings.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to the technical field of lighting, and specifically relates to a lamp which allows both relative rotation and relative telescopic motion between a cap and housing. 
       BACKGROUND ART 
       [0002]    Typically, a lamp comprises a cap, housing and light source, where at least a part of the light source is accommodated in the housing, the lamp is used by mounting of the cap on a socket, and common modes of connecting the cap and housing include insert-pull out, insert-rotate, or rotate. Upon mounting the lamp on the socket, the positions of the lamp and socket are fixed with respect to each other, and the lamp cannot undergo rotational or telescopic movement with respect to the socket, thereby causing considerable inconvenience. For example, upon mounting a directional LED lamp on the socket, because the lamp is unable to rotate relative to the socket, it is sometimes impossible to adjust the LED light source to illuminate the desired direction. Furthermore, lamps come in a vast array of shapes and sizes, and as the lamp cannot extend or contract relative to the socket, in many cases where the lamp is installed in the fitting, the center of illumination may not match the optical center of the fitting, thereby resulting in the issue of uneven illumination. 
       SUMMARY OF THE INVENTION 
       [0003]    In order to resolve the issues above, the objective of the present invention is to disclose a lamp which allows both relative rotation and relative telescopic motion between a cap and its housing, thereby facilitating adjustment of illumination direction, which is also adaptable to different types of fittings. 
         [0004]    The lamp of the present invention, mounted on a socket when in use, comprises a cap, a housing, and a light source, wherein the cap is adapted to connect to the socket, one of the cap and the housing comprises a tubular body, and the other comprises a cylindrical cavity for accommodating the tubular body, and the tubular body rotates in the cylindrical cavity around an axis of the cap and moves along the axial direction of the cap to effect relative rotation and relative telescopic motion between the cap and the housing. 
         [0005]    As an embodiment, one of the outside surface of the tubular body and the side wall of the cylindrical cavity has a protrusion, while the other has at least two circular slots and at least one linear slot, the protrusion slides in any one of the at least two circular slots to effect relative rotation between the cap and the housing, and the protrusion slides in at least one of the linear slots to effect relative telescopic motion between the cap and housing. 
         [0006]    In another embodiment, the tubular body comprises a rigid portion and a flexible portion, the outside surface of the flexible portion has a positioning member, the side wall of the cylindrical cavity has at least two circular slots, the positioning member slides in any one of the at least two circular slots to effect relative rotation between the gap and the housing, and the positioning member moves across the at least two circular slots through an elastic deformation of the flexible portion to effect relative telescopic motion between the cap and the housing. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an exploded view of the first embodiment of the present invention; 
           [0008]      FIG. 2  is a bottom elevation view of the bottom cover  22  of the first embodiment of the present invention; 
           [0009]      FIG. 3  is a front view of the first embodiment of the present invention; 
           [0010]      FIG. 4  is a cutaway view of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. 
         [0012]      FIG. 1  shows an exploded view of a lamp according to a first embodiment of the invention, the lamp comprising a cap  10 , housing  20 , and a light source (not shown) at least partially accommodated within the housing  20 . 
         [0013]    The cap  10  comprises a rigidly connected first portion  11  and a second portion  12 , the first portion  11  of the cap is adapted to connect to a socket (not shown), the second portion  12  of the cap comprises a tubular body  40 , the axis of the tubular body  40  being the axis of the cap  10 , and the tubular body  40  has opposing first end and second end, wherein the first end of the tubular body  40  is rigidly connected to the first portion  11  of the cap. The tubular body  40  comprises two rigid portions  41 ,  42  and two flexible portions  43 ,  44 , the two rigid portions  41 ,  42  being the same in size and symmetrical in position, and the two flexible portions  43 ,  44  being the same in size and symmetrical in position, the rigid portions  41 ,  42  and the flexible portions  43 ,  44  are formed by four slits  49  longitudinally laid out along the tubular body  40 , each slit  49  either running through the tubular body  40  or running through a part of the second end of the tubular body  40  near the tubular body  40 , the larger areas between two adjacent slits  49  being the rigid portions  41 ,  42 , while the smaller areas between two adjacent slits  49  being the flexible portions  43 ,  44 , with one end of the flexible portions  43 ,  44  rigidly connected to the first portion  11  of the cap, while the other end may undergo elastic deformation under the action of an external force to move closer to or further away from the axis of the tubular body  40 . An outside surface of one of the rigid portions  41  has a protrusion  45 , and outside surfaces of both flexible portions  43 ,  44  respectively have positioning members  47 ,  48  (positioning member  48  is not shown), wherein in the first embodiment, protrusion  45  is a cylindrical protrusion, and positioning members  47 ,  48  are smooth surface hemispherical protrusions, the positioning members  47 ,  48  having the same height as protrusion  45 , but the diameter of the hemispherical protrusions being slightly greater than the width of the protrusion  45 . Protrusion  45  and positioning members  47 ,  48  can also take other shapes and sizes. Moreover, cap  10  further comprises a limiting column  61 , extending along the axis of the tubular body  40 , one end of the limiting column  61  rigidly connected to the first portion  11  of the cap, with the other end freely extending beyond the tubular body  40 . 
         [0014]    The housing  20  comprises two top covers  21 ,  23 , a bottom cover  22 , and a shade  24 . At least one portion of the top cover  21  and at least one portion of the bottom cover  22  may enclose a cylindrical cavity  50 , the cylindrical cavity  50  can accommodate the tubular body  40 , the top cover  23  is adapted to accommodate the light source, while the top cover  23  may further comprise a heat dissipation member. The side wall of the cylindrical cavity  50  has a plurality of circular slots  52  and a linear slot  51 , permitting the protrusion  45  of the rigid portion  41  of the tubular body  40  to slide freely therein. As shown in  FIG. 2 , the circular slots  52  are formed from a plurality of circular protrusions  53  positioned at equally-spaced intervals on the side wall of the cylindrical cavity  50 , the width of each circular slot  52  is greater than the width of the protrusion  45 , but is slightly less than the diameter of the positioning members  47 ,  48 , therefore when the positioning members  47 ,  48  slide within the circular slot  52 , they function to increase the friction of rotation. The linear slot  51  is positioned at the bottom of the cylindrical cavity  50  along the longitudinal direction thereof, and is formed by removing a portion of the bottom of the circular protrusions  53 , such that the linear slot  51  joins the circular slot  52 , and the protrusion  45  is able to slide from the linear slot  51  into the circular slot  52  or from the circular slot  52  into the linear slot  51 , while the circular protrusion  54  near the opening of the cylindrical cavity  50  is intact, and is adapted to form the circular slot  52  closest to the opening while also serving as a blocking member of the linear slot  51  to prevent the protrusion  45  detaching from the linear slot  51  during its movement therein. Moreover, the top cover  23  further comprises a limiting hole  62 , which is positioned on the axis of the cylindrical cavity  50  and mates with the limiting column  61  of the cap  10 ; upon completing assembly of the lamp of the present embodiment, the limiting column  61  is inserted into the limiting hole  62 , and remains there throughout the relative rotation and relative telescopic movement of the cap  10  and the housing  20  so as to prevent the housing  20  and the cap  10  from breaking apart due to the large radial forces experienced at the point of furthest distance between the cap  10  and the housing  20 . 
         [0015]      FIG. 3  shows a front view of the lamp according to the first embodiment of the invention, while  FIG. 4  shows a cutaway view of the lamp according to the first embodiment of the invention. In order to facilitate installation of the lamp, the limiting column  61  of the cap  10  is typically first inserted into the limiting hole  62  of the housing  20 , whereupon the tubular body  40  is fitted between the top cover  21  and bottom cover  22  of the housing  20  before assembling the top cover  21  and bottom cover  22  together, so that the tubular body  40  is enclosed within the cylindrical cavity  50 . 
         [0016]    When the tubular body  40  is in place inside the cylindrical cavity  50 , the axis of the cylindrical cavity  50  coincides with the axis of the tubular body  40 , which is also the axis of the cap  10 . As the protrusion  45  of the tubular body  40  slides within one of the circular slots  52 , relative rotation is enabled between the cap  10  and the housing  20 , while the positioning members  47 ,  48  also slide within the circular slots  52  corresponding to their positions, and serve to increase friction during the rotation process; when the protrusion  45  in the circular slot  52  slides to the point of intersection with the linear slot  51 , relative telescopic motion is enabled between the cap  10  and the housing  20 , and when the protrusion  45  slides in the linear slot  51 , the positioning members  47 ,  48  move across the plurality of circular slots  52  through an elastic deformation of the flexible portions  43 ,  44 , in addition, after the cap  10  and the housing  20  are adjusted to a particular relative position, the positioning members  47 ,  48  serve a positioning function to prevent any arbitrary telescopic motion of the cap  10  relative to the housing  20 . 
         [0017]    In actual use, upon mounting the lamp of the present embodiment on a socket, the first portion  11  of the cap is rigidly connected to the socket, whereupon the operator may, as required, rotate the housing  20  around the axis of the cap  10 , and the light source in the housing will rotate along therewith so as to adjust the direction of illumination, or alternatively, once the housing  20  is rotated to a particular angle (i.e. the protrusion  45  enters the linear slot  51 ), the housing  20  may be pulled in the axial direction of the cap  10  for telescopic adjustment to adjust the relative position of the housing and the cap so as to adapt to the fitting within which the lamp is installed. 
         [0018]    The upper limit of relative telescopic motion between the cap  10  and the housing  20  depends on the length of the linear slot  51 ; the longer the cylindrical cavity, the longer the linear slot  51 , and the longer the distance that the protrusion  45  on the outer surface of the tubular body  40  can slide therein, therefore allowing more telescopic adjustment between the cap  10  and housing  20 . For a given linear slot  51  length, the precision of telescopic adjustment between the cap  10  and housing  20  will depend on the number of circular slots  52 ; the greater the number of circular slots  52 , the narrower the width of each individual circular slot  52 , and the smaller the minimum permissible telescopic adjustment between the cap  10  and the housing  20 , i.e. the higher the precision of the telescopic adjustment. Therefore, the length of the linear slot  51  and the number of circular slots  52  may be designed according to specific needs. 
         [0019]    As another embodiment, outside surfaces of the two rigid portions  41 ,  42  of the tubular body  40  each has a protrusion  45 ,  46  respectively, the two protrusions  45 ,  46  being positioned along the diameter of a cross section of the tubular body or cylindrical cavity; at the same time, two linear slots  51  are provided on the side wall of the cylindrical cavity  50  to respectively enable sliding of the two protrusions  45 ,  46 , and thereby effect relative telescopic motion between the cap  10  and housing  20 . The advantage of having two protrusions  45 ,  46  is that during the relative rotation of the cap  10  and housing  20 , the two protrusions  45 ,  46  slide within the same circular slot  52  and are able to render the relative rotation between the cap  10  and housing  20  more stable. 
         [0020]    The light source for the lamp of any embodiment of the invention may be selected from one of a light emitting diode (LED), organic light emitting diode (OLED), incandescent lamp, halogen lamp, and gas discharge lamp; or the like. 
         [0021]    The lamp of a second embodiment of the present invention differs from the lamp of the first embodiment in that no protrusions  45  are provided on the outer surfaces of the rigid portions  41  and  42  of the tubular body  40 , and only positioning members  47 ,  48  are provided on the outer surfaces of the flexible portions  43 ,  44 , while no linear slot  51  is provided on the side wall of the cylindrical cavity  50 , instead only the plurality of circular slots  52  are provided. In this arrangement, relative rotation of the cap  10  and the housing  20  is accomplished through positioning members  47 ,  48  sliding within the circular slots  52 , while relative telescopic motion of the cap  10  and the housing  20  is accomplished through the positioning members  47 ,  48  moving across the circular slots  52  under the elastic deformation of the flexible portions  43 ,  44 . 
         [0022]    While the present invention has been described in connection with specific embodiments thereof, it will be understood by those skilled in the art that many modifications and variations can be made thereto. It is therefore to be understood that the appended claims are intended to cover all such modifications and alterations insofar as they fall within the true spirit and scope of the invention.