Abstract:
A projecting lamp for projecting images to create visual and decorative effect is provided. The projecting lamp mainly includes a lamp cylinder mounted on a supporting structure. A projecting structure is mounted in a front opening of the lamp cylinder and includes a focus control bar. By rotating a threaded body of the focus control bar, a distance between a projecting lens located at a front of the projecting structure and a projecting picture located at a rear of the projecting structure is finely adjusted to enable projection of a magnified and clear image. The lamp cylinder is adjustable in its elevation angle and its angular position in a plane. The whole projecting lamp may be quickly disassembled for easy storage and conveyance.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a projecting lamp for projecting images to create visual and decorative effect, and more particularly to a projecting lamp having a focus control bar adapted to finely adjust focus of the projecting lamp to project clear image. 
     BACKGROUND OF THE INVENTION 
     There are various types of projecting lamps available in the markets, some of which have simple structure while others have complicate structure. These projecting lamps may be used in very wide applications, such as making reports, creating visual and decorative effects, etc. 
     FIGS. 10A and 10B show a conventional projecting lamp currently available in the market. The projecting lamp includes a hollow cylinder  81  fixedly mounted to a top of a stand  80 . An illuminating means capable of emitting intensive light is mounted in a closed rear end of the cylinder  81 , and a picture holder  83  holding a projecting picture  82 , a locating ring member  84 , and a front ring member  86  holding a projecting lens  85  are sequentially mounted in an open front of the cylinder  81  from inner side to outer side. And, two straight rods  8  are rearward extended through the front and the locating ring members  86 ,  84  to connect their rear ends to the picture holder  83 . To use the projecting lamp, the illuminating means is turned on for the same to emit light. The emitted light passes through the projecting picture  82  and the projecting lens  85 , so that an image on the projecting picture  82  is projected and magnified on a plane, such as a wall surface. 
     Since a distance between the projecting lamp and the wall surface varies, it is necessary to adjust a distance between the projecting picture  82  and the projecting lens  85  to project a clear image on the wall surface. In FIG. 10A, the distance between the projecting picture  82  and the lens  85  is large. By pulling the straight rods  8  outward, the distance is shortened, as shown in FIG.  10 B. To effect focus control in the conventional projecting lamp, an operator must hold the two straight rods  8  at the same to pull or push them in order to obtain a desired focus. Since there is only a very small adjustable distance between the projecting picture  82  and the lens  85 , it is difficult for the operator to apply a suitable magnitude of force on the two straight rods  8  in one direction to obtain the desired focus. It is very possible one movement of the rods  8  would bring the projecting picture  82  to be too close to or too far away from the lens  85 . Moreover, only one minor touch or vibration of the projecting lamp would possibly result in undesirable change in the adjusted focus, causing inconvenience in using the projecting lamp. 
     Further, the above-described focusing structure of the conventional projecting lamp assembled from the projecting picture  82 , the lens  85  and the straight rods  8  is fixed in the cylinder  81  through a frictional contact of an inner wall surface of the cylinder  81  with a plurality of leaf springs  841  extended from the lens holder  83  and the locating ring member  84 . The leaf springs  841  tend to scrap against and therefore damage the inner wall of the cylinder  81 . Moreover, the leaf springs  841  are subject to elastic fatigue after they have been used for a prolonged time and therefore lose their intended function of holding the focusing structure in the cylinder  81 . 
     In the conventional projecting lamp, the cylinder  81  is mounted on a top of a vertical stand  80 . It is difficult to adjust the cylinder  81  to different elevation angles and it is impossible to rotate the cylinder  81  in a plane relative to the stand  80  to a desired direction. 
     Therefore, it is desirable to develop an improved projecting lamp to eliminate the drawbacks existing in the conventional projecting lamps. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a projecting lamp that includes a projecting structure and a focus control bar that work together to enable easy and fine adjustment of a distance between a projecting picture and a projecting lens of the projecting lamp, and the adjusted focus of the projecting lamp is not subjected to easy change due to vibration or collision. 
     Another object of the present invention is to provide a projecting lamp having a lamp cylinder that is adjustable in its elevation-angle and angular position. 
     A further object of the present invention is to provide a projecting lamp that can be quickly disassembled for easy storage or conveyance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
     FIGS. 1A and 1B are front and rear perspective views, respectively, of a projecting lamp according to the present invention; 
     FIG. 2 is an exploded perspective of the projecting lamp of FIG. 1; 
     FIGS. 3A and 3B are perspective views showing the projecting structure of the projecting lamp of the present invention and the positioning of a projecting picture into the projecting structure; 
     FIGS. 4A and 4B are side views showing the adjustment of the focus control bar of the projecting lamp of the present invention; 
     FIGS. 5A and 5B are perspective views showing the operation of the focus control bar of the projecting lamp of the present invention; 
     FIGS. 6A and 6B are perspective views of the lamp cylinder of the present invention with the projecting structure mounted therein; 
     FIG. 7 is a perspective showing the adjustment of the lamp cylinder of the present invention to a desired elevation angle; 
     FIGS. 8A and 8B are perspective views showing the rotation of the lamp cylinder of the present invention within a plane; 
     FIG. 9 shows the focus control of the present invention to project a clear image; and 
     FIGS. 10A and 10B are partially sectioned perspective views of a conventional projecting lamp. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to FIGS. 1A,  1 B and  2  that are front, rear, and exploded perspective views, respectively, of a projecting lamp according to the present invention for producing images that are visually attractive and function as decorations. As shown, the projecting lamp mainly includes a lamp cylinder  1 , a transformer  12 , a projecting structure  2 , a connecting means  3 , a supporting post  4 , a base  5 , and a predetermined number of feet  6 . 
     The lamp cylinder  1  is a hollow cylindrical member having a front opening  13 . Two diametrically opposite first threaded holes  131  are provided on the lamp cylinder  1  adjacent to the front opening  13  for two screws  11  to thread thereinto. An illuminating means (not shown) is mounted in the lamp cylinder  1  to an inner rear end thereof to serve as a light source. Two diametrically opposite second threaded holes  14  are provided on the cylinder lamp  1  at a middle point thereof. Washers  141  are fitted around the second threaded holes  14 . 
     The transformer  12  is connected to an outer rear end of the lamp cylinder  1  to electrically connect to the illuminatingmeans in the lamp cylinder  1 . An electric cord  121  is connected at one end to the transformer  12  and at another end to a wall-mount socket (not shown) to supply stable power to the illuminating means. 
     Please refer to FIGS. 2,  3 A and  3 B. The projecting structure  2  is mounted in the front opening  13  of the lamp cylinder  1  and mainly includes a focus control bar  21 , a projecting lens  22 , a lens holder  221 , a front ring member  23  behind the lens holder  221 , a middle ring member  24 , and a rear ring member  25 . 
     The lens holder  221 , the front ring member  23  and the middle ring member  24  respectively define a first round hole  28  via which light emitted by the illuminating means pass to project an image. The rear ring member  25  defines a second round hole  28  having a size the same as that of a projecting picture  7 . The second round hole  28  is provided along a lower half with a semicircular channel  251  into or from which the projecting picture  7  can be quickly inserted or removed. 
     The projecting lens  22  is fixedly sandwiched between the lens holder  221  and the front ring member  23  by bolts and nuts, so that the projecting lens  22  is aligned with the first round holes  28  and a clearance  222  exists between the lens holder  221  and the front ring member  23 . 
     The middle ring member  24  and the rear ring member  25  are separately fixedly connected to two ends of three parallel fixing threaded rods  26  to form a unit, so that the middle and the rear ring members  24 ,  25  always stably move together in the lamp cylinder  1  in the same direction. Two spaced guide bars  27  have one externally threaded end screwed into the clearance  222  between the lens holder  221  and the front ring member  23  and another end extended through the middle ring member  24  and the rear ring member  25  to project from the rear ring member  25 , such that the unit of the middle and the rear ring members  24 ,  25  is allowed to smoothly slide on and along the guide bars  27 . 
     The focus control bar  21  includes a handle portion  211  forward extended through the front ring member  23  and the lens holder  221  to project from the lens holder  221  for an operator to conveniently hold thereat, and an externally threaded body portion  212  rearward extended from the handle portion  211  to thread through a threaded hole on the middle ring member  24 . Thus, when the focus control bar  21  is rotated at the handle portion  211 , the handle portion  211  is freely rotatable without moving the lens holder  221  and the front ring member  23  while the threaded body portion  212  would bring the middle ring member  24  to axially move along the focus control bar  21 . Since the rear ring member  25  is distantly connected to the middle ring member  24  through the three fixing rods  26 , the unit of the middle and the rear ring members  24 ,  25  axially moves on and along the focus control bar  21  and the guide bars  27 . This arrangement allows fine adjustment of a distance between the projecting picture  7  inserted in the semicircular channel  251  on the rear ring member  25  and the projecting lens  22  by rotating the focus control bar  21  at the handle portion  211  and thereby obtain a desired focus for the projecting lamp. 
     FIGS. 4A and 4B are side views showing the focus control of the projecting lamp via the focus control bar  21 . In FIG. 4A, an initial distance between the front ring member  23  and the middle ring member  24  is L 1 . When an operator grips at the handle portion  211  to turn the focus control bar  21  and cause the middle ring member  24  to axially move along the threaded body portion  212  of the focus control bar  21  toward the front ring member  23 , the distance L 1  between the middle and the front ring members  24 ,  23  is shortened to a difference distance L 2 , as shown in FIG.  4 B. That is, the rear ring member  25  having the projecting picture  7  attached thereto could be axially finely moved along with the middle ring member  24  through turning the focus control bar  21  to achieve the focus control. 
     FIGS. 5A and 5B are perspective views showing the operation of the projecting structure  2  of the projecting lamp of the present invention. When the focus control bar  21  is rotated, the middle and the rear ring members  24 ,  25  connected together by the fixing rods  26  are brought to axially move at the same time, enabling adjustment of distance between the lens  22  and the projecting picture  7  on the semicircular channel  251  on the rear ring member  25 . 
     FIGS. 6A and 6B are perspective views of the lamp cylinder  1  with the projecting structure  2  mounted therein, showing the focus control bar  21  is rotated to adjust the distance between the lens  22  and the projecting picture  7 . 
     Please refer back to FIG.  2 . The connecting means  3  is a U-shaped member being provided at two ends and a center with threaded holes  31   a ,  31   b , and  32 , respectively. The lamp cylinder  1  is adapted to suspend in the U-shaped connecting means  3  by tightening two first adjusting screws  311   a  and  311   b  through the two threaded holes  31   a ,  31   b  at two ends of the U-shaped connecting means  3  into the two second threaded holes  14  on the lamp cylinder  1 . Please refer to FIGS. 2 and 7 at the same time. By properly loosening the two first adjusting screws  311   a ,  311   b , the lamp cylinder  1  can be pivotally turned relative to the connecting means  3  to a desired elevation angle. Please refer to FIGS. 8A and 8B. A second adjusting screw  321  is downward threaded through the threaded hole  32  at the center of the U-shaped connecting means  3  into a top of the supporting post  4 . When the second adjusting screw  321  is properly loosened, the lamp cylinder  1  could be rotated in a plane by 360 degrees relative to the supporting post  4 , as indicated by the dotted lines in FIG.  8 B. 
     Please refer back to FIG. 2 again. The base  5  is provided at a top with a fixing hole  51  for firmly receiving a lower end of the supporting post  4  therein. A lower portion of the base  5  is provided with a predetermined number of guide grooves  52  into which feet  6  are detachably connected for the projecting lamp of the present invention to stand stably. 
     When the projecting lamp of the present invention is in a fully assembled state as shown in FIGS. 1A and 1B, and the electric cord  121  is plugged into a power source, such as a general wall-mount socket, for the illuminating means to emit light, the emitted light will pass through the projecting picture  7  and the lens  22 , and an image  71  on the projecting picture  7  is magnified and projected on a plane, as shown at the right side of FIG.  9 . At this point, the operator may adjust the horizontal position and the elevation angle of the lamp cylinder  1  according to the position of the plane onto which the image  71  on the projecting picture  7  is to be projected. Thereafter, the operator may turn the focus control bar  21  leftward or rightward to adjust the distance between the projecting picture  7  and the lens  22  until a clear projected image  71  is obtained. 
     Please note that the focus control bar  21  is a threaded bar. By turning the focus control bar  21 , a precise fine adjustment of the distance between the picture  7  and the lens  22  is allowable. The focus control bar  21  is therefore superior to the straight rods  8  in the conventional projecting lamp. 
     The semicircular channel  251  provided on the rear ring member  25  provides a very easy way to change the projecting picture  7  in the projecting structure  2 . The operator needs only to loosen the two screws  11  and remove the projecting structure  2  from the opening  13  of the lamp cylinder  1 . Since the semicircular channel  251  is located at the most outer side of the projecting structure  2 , the projecting picture  7  inserted therein can be easily extracted and replaced with another projecting picture having different design. The projecting structure  2  with a new projecting picture  7  can be then mounted into the lamp cylinder  1  via the opening  13  and the screws  11  are tightened again to resume a complete projecting lamp for use. 
     Since the threaded body portion  212  of the focus control bar  21  is engaged with a threaded hole on the middle ring member  24 , the middle ring member  24  is not subject to easy moving on the threaded body portion  212  of the focus control bar  21  due to vibration or collision during normal operation or use of the projecting lamp. That is, the adjusted distance between the projecting picture  7  and the lens  22 , or the adjusted focus of the projecting lamp, is not easily affected by general vibration or collision of the projecting lamp. 
     Moreover, unlike the conventional projecting structure that is frictionally fitted in the lamp cylinder through leaf springs  841  that are subjected to elastic fatigue, the projecting structure  2  is fixed in the front opening  13  of the lamp cylinder  1  by threading the screws  11  through the first threaded holes  131  on the lamp cylinder  1  into the clearance  222  between the lens holder  221  and the front ring member  23 . Therefore, the projecting lamp of the present invention is structurally more durable for use. 
     The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.