Abstract:
A door videophone capable of rotating a camera, comprising: a main body having a monitor for displaying an image of a caller, and being located indoors; a bell box having the camera for photographing looks of the caller and transmitting the image of the caller to the monitor, and being located outdoors; an actuating device for rotating the camera, and being disposed in the bell box; and a control device for generating an operation control signal associated with the actuating device, and being disposed at the main body.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a door videophone for visually observing an outdoor caller and talking with the caller, and, more particularly, to a door videophone capable of rotating a camera in order to observe total looks of an outdoor caller. 
     DESCRIPTION OF THE PRIOR ART 
     Generally, when a caller calls at a person&#39;s house, it is necessary that a host of the house observes whether the caller is acquaintance or not and, then, opens a door. 
     Referring to FIG. 1, there is shown a conventional door videophone for observing a caller. 
     As shown in FIG. 1, the conventional door videophone includes a main body  10  having a monitor  12 , a bell box  20  having a camera  22  for transmitting image of a caller to the monitor  12 , an electronic lock  30  disposed at door and a power supply  40  for providing electric current to the main body  10 , the monitor  20  and the lock  30 . The main body  10  is located indoors and the bell box  20  is located outdoors. 
     The main body  10  also has a release switch  14  for unlocking the electronic lock  30 , a hook switch  16  for operating the monitor  12  and a handset  18  for talking with the caller. The hook switch  16  is turn on when the handset  18  is lifted. 
     The bell box  20  also has a bell switch  24  for ringing a bell. 
     The operation of the conventional door videophone structured as above-mentioned will be explained. 
     When the caller turns on the bell switch  24  to ring the bell, a host lifts the handset  18  to turn on the hook switch  16 . In this case, the image of the caller photographed by the camera  22  is displayed on the monitor  12  so that the host can observe the caller and, then, the host turns on the release switch  14  to unlock the electronic lock  30 . 
     However, in the conventional door videophone, since the photographing direction of the camera cannot be adjusted, photographing area of the camera is extremely limited. 
     Therefore, when the caller gets out of the photographing area, the camera cannot photograph the total looks of the caller and, consequently, the host cannot correctly observe looks of the caller through the monitor. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a door videophone capable of rotating a camera to enlarge a photographing area of the camera. 
     In accordance with an aspect of the present invention, there is provided a door videophone capable of rotating a camera, comprising: a main body having a monitor for displaying an image of a caller, and being located indoors; a bell box having the camera for photographing looks of the caller and transmitting the image of the caller to the monitor, and being located outdoors; an actuating means for rotating the camera, and being disposed in the bell box; and a control means for generating an operation control signal associated with the actuating means, and being disposed at the main body. 
     In accordance with another aspect of the present, there is provided an actuator for rotating a camera upward, downward, left and right, comprising: a base plate for supporting the camera; at least one first driving means for generating a rotation force to rotate the base plate upward and downward; at least one first transmitting means for transmitting the rotation force generated by the first driving means to the base plate; at least one second driving means for generating a rotation force to rotate the base plate left and right; at least one second transmitting means for transmitting the rotation force generated by the second driving means to the base plate; and a control means for generating an operation control signal associated with the first and second driving means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in connection with the accompanying drawings, in which: 
     FIG. 1 is a system diagram showing a structure of a door videophone of a prior art; 
     FIG. 2 is a system diagram illustrating a structure of a door videophone in accordance with a preferred embodiment of the present invention; 
     FIG. 3 is a disassembled perspective view depicting an embodiment of an actuator employed in the door videophone of the present invention; 
     FIGS. 4A to  4 D are perspective views schematically representing an operation state of the door videophone illustrated in the FIG. 3; 
     FIG. 5 is a disassembled perspective view showing another embodiment of the actuator employed in the door videophone of the present invention; 
     FIG. 6 is a schematic cross-sectional view of the door videophone assembling the actuator of the FIG. 5; and 
     FIGS. 7A to  7 D are perspective views schematically representing an operation state of the door videophone illustrated in the FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of a door videophone in accordance with a present invention will be described in detail, referring to the accompanying FIGS. 2 to  7 D. 
     Referring to FIG. 2, there is shown a system diagram illustrating a structure of the door videophone in accordance with the present invention. 
     The door videophone in accordance with the present invention comprises a main body  100  having a monitor  110 , a bell box  200  having a camera  210  for transmitting an image of a caller to the monitor  110 , an actuator  300  for rotating the camera  210 , an electronic lock  400  disposed in a door and a power supply  500  for providing electric current to the main body  100 , the bell box  200 , the actuator  300  and the lock  400 . 
     The main body  100  includes a handset  120  for transmitting/receiving a voice signal, a release switch  130  for unlocking the electronic lock  400 , a control switch  140  for generating an operation control signal associated with the actuator  300  and a hook switch  150  for turning on the monitor  110 . Normally, the handset  120  is placed on the hook switch  150 . In this state, when a host lifts the handset  120 , the image photographed by the camera  210  is displayed on the monitor  110 . The surface of the control switch  140  has four arrows respectively indicating upper, lower, left and right directions so that the host may easily adjust rotation direction of the camera  210  to be rotated by operation of the actuator  300 . 
     The bell box  200  also includes a microphone and speaker  220  for transmitting/receiving the voice signal to/from the handset  120  and a bell switch  230  for ringing a bell. 
     FIG. 3 is a disassembled perspective view depicting an embodiment of the actuator employed in the door videophone of the present invention. 
     Referring to FIG. 3, the actuator  300  includes a base plate  310  for supporting the camera  210 , a first driving motor  320  for rotating the base plate  310  in left and right direction as the operation control signal is outputted from the control switch  140 , a second driving motor  330  for rotating the base plate  310  in upper and lower direction as the operation control signal and a bracket  340  for supporting the base plate  310 . The first and second driving motors  320  and  330  are spaced out substantially 90 degrees from each other and the bracket  340  is spaced out substantially 135 degrees from each of the first and second driving motors  320  and  330 . Preferably, a shock absorber  350  is disposed between the camera  210  and base plate  310 . The shock absorber  350  prevents a vibration caused by operation of the first or second driving motor  320  or  330  from being transmitted to the camera  210 . The shock absorber  350  may be made of rubber, plastic and the like having an elasticity. 
     In this embodiment, the peripheral surface of the base plate  310  is a convex surface having a predetermined curvature. The base plate  310  has first and second rails  312  and  314  respectively positioned at portions of the base plate  310  facing with the first and second driving motors  320  and  330 . The first and second rails  312  and  314  have a predetermined length along the curvature of the peripheral surface of the base plate  310 . 
     In this case, the actuator  300  further includes first and second guide blocks  322  and  332  respectively disposed at driving shafts of the first and second driving motors  320  and  330 . The first and second guide blocks  322  and  332  respectively have first and second grooves  324  and  334  for inserting each of the first and second rails  312  and  314  thereinto. Each of the first and second grooves  324  and  334  has a predetermined length along the curvature of the peripheral surface of the base plate  310  and a width substantially equal to that of each of the first and second rails  312  and  314 . Preferably, the width of each of the first and second grooves  324  and  334  is wider than each of the first and second rails  312  and  314 . Further, front surface of each of the bracket  340 , first and second guide blocks  322  and  332  have a curvature substantially equal to that of the peripheral surface of the base plate  310  to be closely contacted to the peripheral surface of the base plate  310 . Therefore, when the first driving motor  320  is driven to rotate the first guide block  322 , rotation force of the first guide block  322  is transmitted to the first rail  312  to rotate the base plate  310  in left or right direction. Simultaneously, the second rail  314  is moved along the second groove  334 . To control the rotation force generated from the first and second driving motors  320  and  330 , a reduction gear may be respectively disposed between each of the first and second guide blocks  322  and  332  and each of the driving shafts of the first and second driving motors  320  and  330 . 
     Further, when the second driving motor  330  is driven to rotate the second guide block  332 , rotation force of the second guide block  332  is transmitted to the second rail  314  to rotate the base plate  310  in an upper or lower direction. Simultaneously, the first rail  312  is moved along the first groove  324 . 
     Preferably, the bell box  200  also has a first and second support  326  and  336  for respectively supporting lower portion of the first and second guide blocks  322  and  332 . In this case, the lower portion of each of the first and second guide blocks  322  and  332  takes the shape of semi-cylinder, and upper portion of each of the first and second supports  326  and  336  has a semi-cylindrical recess. Preferably, a first bearing  328  is disposed between the first guide block  322  and the first support  326  so that the first guide block  322  is smoothly rotated. Also, a second bearing  338  is disposed between the second guide block  332  and the second support  336  so that the second guide block  332  is smoothly rotated. Further, a bearing  342  is disposed between the base plate  310  and the bracket  340  so that the base plate  310  is smoothly rotated. 
     Detailed description for the electronic lock  400  employed in the door videophone capable of rotating the camera is omitted because it has been known. 
     Hereinafter, operation of the door videophone capable of rotating the camera in accordance with the present invention will be described in detail, referring to FIGS. 4A to  4 D. 
     When a caller turns on the bell switch  230  of the bell box  200  to ring the bell, a host lifts the handset  120  to turn on the hook switch  150  after hearing the bell. Then, the image of the caller photographed by the camera  210  is displayed on the monitor  110 . 
     In this case, when the caller gets out of a photographing area of the camera  210  and, therefore, the camera  210  does not photograph the total looks of the caller, the host turns on the control switch  140  to rotate the camera  210  toward the caller. Then, the host may correctly observe the caller. 
     That is, referring to FIG. 4A, when the host presses the upper arrow of the control switch  140  to drive the second driving motor  330  clockwise, the second guide block  332  fixed to the driving shaft of the second driving motor  330  is rotated upwardly. Then, rotation force of the second guide block  332  is transmitted to the base plate  310  through the second rail  314  inserted into the groove  334  and, therefore, rotates the base plate  310  and camera  210  disposed at the base plate  310 . Simultaneously, the first rail  312  is moved backwards along the groove  324  of the first guide block  322 . On the contrary, referring to FIG. 4B, when the host presses the lower arrow of the control switch  140  to drive the second driving motor  330  counterclockwise, as in the above-mentioned principle, the base plate  310  and camera  210  disposed at the base plate  310  are rotated downward. 
     Further, referring to FIG. 4C, when the host presses the left arrow of the control switch  140  to drive the first driving motor  320  clockwise, the first guide block  322  fixed to the driving shaft of the first driving motor  320  is rotated left. Then, rotation force of the first guide block  322  is transmitted to the base plate  310  through the first rail  312  inserted into the groove  324  to rotate the base plate  310  and the camera  210  disposed at the base plate  310 . Simultaneously, the second rail  314  is moved backwards along the groove  334  of the second guide block  332 . On the contrary, referring to FIG. 4D, when the host presses the right arrow of the control switch  140  to drive the first driving motor  320  counterclockwise, as in the above-mentioned principle, the base plate  310  and camera  210  disposed at the base plate  310  are rotated right. 
     Referring to FIGS. 5 and 7D, there is shown another embodiment of the actuator employed in the door videophone of the present invention. 
     Referring to FIGS. 5 and 6, the actuator in accordance with another embodiment of the present invention includes a base plate  600  for supporting the camera  210  thereon, a housing  610 , first and second driving motors  620  and  630  respectively having first and second worm gears  622  and  632 , a first wheel gear  640  engaged with the first worm gear  622  and a second wheel gear  650  engaged with the second worm gear  632 . 
     The first and second motors  620  and  630  are respectively driven as the control signal is outputted from the control switch  140 , clockwise or counterclockwise. Further, when the first and second driving motors  620  and  630  are driven, the first and second wheel gears  640  and  650  respectively engaged with the first and second worm gears  622  and  632  are rotated. The first and second wheel gears  640  and  650  are spaced out about 90 degrees from each other. 
     In this case, first and second screw shafts  642  and  652  are respectively disposed on center portion of the first and second wheel gears  640  and  650 . Each of the first and second screw shafts  642  and  652  are rotated together with each of the first and second wheel gears  640  and  650 . 
     Further, first and second racks  660  and  670  are respectively disposed on portions of the base plate  600  facing with the first and second screw shafts  642  and  652 . The first and second racks  660  and  670  are joined to the base plate  600  in the universal joint type. The first and second racks  660  and  670  are respectively engaged with the first and second screw shafts  642  and  652 . Therefore, the first and second racks  660  and  670  are respectively moved by rotation of each of the first and second screw shafts  642  and  652 , upward or downward. The first and second racks  660  and  670  are substantially cylindrical in shape having screw thread capable of being respectively engaged with the first and second screw shafts  642  and  652  therein. 
     The actuator in accordance with the embodiment also has a support  680  disposed between the first and second motors  620  and  630 , and a shock absorber  690  disposed between the base plate  600  and the camera  210 . The support  680  is contacted to back surface of the base plate  600 . The support  680  can rotate around its center portion. The shock absorber  690  prevents a vibration caused by operation of the first or second driving motors  620  or  630  from being transmitted to the camera  210 . 
     Referring to FIG. 7A, when a host turns on the upper arrow of the control switch  140  to drive the first driving motor  620 , the worm gear  622  rotates to move the first wheel gear  640  and first screw shaft  642  clockwise. Then, the first rack  660  engaged with the first screw shaft  642  is moved backward to rotate the base plate  600  and the camera  210  upward. 
     On the contrary, referring to FIG. 7B, when the host turns on the lower arrow of the control switch  140  to drive the first driving motor  620 , the worm gear  622  rotates to move the first wheel gear  640  and first screw shaft  642  counterclockwise. 
     Then, the first rack  660  engaged with the first screw shaft  642  is moved counterclockwise to push the upper portion of the base plate  600  and the camera  210  rotates downward. 
     On the other hand, referring to FIG. 7C, when the host turns on the left arrow of the control switch  140  to drive the second driving motor  630 , the worm gear  632  rotates to move the second wheel gear  650  and second screw shaft  652  clockwise. 
     Then, the second rack  670  engaged with the second screw shaft  652  is moved backward to pull the left portion of the base plate  600  and the camera  210  rotates left. 
     Further, referring to FIG. 7D, when the host turns on the right arrow of the control switch  140  to drive the second driving motor  630 , the worm gear  632  rotates to move the second wheel gear  650  and second screw shaft  652  counterclockwise. 
     Then, the second rack  670  engaged with the second screw shaft  652  is moved forward to push the left portion of the base plate  600  and the camera  210  rotates right. 
     In accordance with the present invention, though the caller gets out the photographing area of the camera, the host rotates the camera to correctly observes the caller. 
     While the present invention has been described with respect to certain preferred embodiments only, other modifications and variation may be made without departing from the spirit and scope of the present invention as set forth in the following claims.