Abstract:
A surveillance camera device is provided which has an impact absorbing structure. The camera device includes a rotary base supporting a camera unit, a rotary bracket supporting the rotary base, and coil springs. The coil springs work to elastically urge the rotary base away from the rotary bracket to as to permit the rotary base to move straight against the mechanical pressure of the springs when subjected to a damaging impact on the device, thereby absorbing the impact to avoid damage to the camera unit.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field of the Invention 
   The present invention relates generally to a surveillance camera, and more particularly to a surveillance camera for use with store security, building security, and any other security applications which has an impact absorbing structure working to avoid damage to an internal structure of the camera. 
   2. Background Art 
   Typical surveillance cameras present an appearance which persons will perceive to be a surveillance camera clearly and gives the impression that they are being watched in order to prevent crimes before happening, but it gives an unpleasant feeling to customers in the store, for example. The surveillance cameras are, thus, unpopular. In order to avoid such a problem, dome-shaped smoky surveillance cameras which are designed not to give people the pressure mentally have become prevalent. Typical surveillance cameras are classified into two types: an automatically angle adjustable type in which a direction of surveillance can be changed from a remote monitor room and an angle fixed type in which a direction of surveillance is fixed upon installation of the camera. 
     FIGS. 5 and 6  illustrate an internal structure of the angle fixed type of conventional dome-shaped surveillance camera device. 
   The camera unit  100  has an image capturing lens  102 , a CCD image sensor, and a circuit substrate which are disposed within a casing  101  and works to convert a captured image into an electrical signal and output it. The casing  101  is retained at a side wall thereof by arms  103   a  of a holder plate  103 . The holder plate  103  is disposed on the bottom of a support plate  104  to be rotatable to yaw the camera unit  100 . The support plate  104  has arms  104   a  and  104   b  which are supported by upright arms  105   a and  105   b  of a rotary bracket  105  through pins  106  and  107  to be rotatable vertically to tilt the camera unit  100 . The rotary bracket  105  has engages at the center thereof a boss  109  of a base plate  108  to be rotatable horizontally to pan the camera unit  100 . The base plate  108  is fixed on a body of the camera device (not shown). The camera device has installed therein a main substrate on which a power supply circuit and an image processing circuit are disposed and also has a power cord and a control cord extending outside the camera device for connection with a commercial power supply and an external camera monitor. A smoky dome-shaped resinous cover is installed on the camera device to cover the camera unit  100 . 
   Such a surveillance camera device is usually suspended from a ceiling or installed on a side wall of a building. The installation is achieved by affixing the camera device to the wall temporarily, connecting the power and control cords to the camera device, panning and tilting the camera device while watching the camera monitor, and fixing the camera device in a desired position. In a case where the camera device is installed on the side wall, a vertical direction of a captured image may be inclined after the angle adjustment. The inclination is corrected by yawing the camera unit  100  to stand the image upright. After the direction in which an image is to be captured is determined, the camera device is fixed firmly on the wall. 
   The surveillance camera device, however, has the drawback in that persons being watched may feel uncomfortable with the surveillance and beat the camera device with, for example, a baseball bat, thus causing damage to an internal structure of the camera device. 
   SUMMARY OF THE INVENTION 
   It is therefore a principal object of the present invention to avoid the disadvantages of the prior art. 
   It is another object of the present invention to provide a surveillance camera device with an impact absorbing structure working to avoid damage to an internal structure of the device. 
   According to one aspect of the invention, there is provided a surveillance camera device which comprises: (a) a camera unit working to capture an image of a surveillance target and output an image signal indicative of the captured image; (b) a supporting member supporting the camera unit; (c) a bracket supporting the supporting member; (d) an elastic member working to elastically urge the supporting member away from the bracket; (e) a mount body on which the bracket is mounted; and (f) a cover installed on the mount body. If the cover is beaten with, for example, a stick, so that a damaging impact is added to the camera unit, it will cause the supporting member to move against elastic pressure of the elastic member, thereby absorbing the impact on the camera unit to avoid damage thereto. When the impact is attenuated, the supporting member is returned by the elastic pressure of the elastic member to an initial position, thus enabling a camera operation to be resumed. 
   In the preferred mode of the invention, the bracket has a support arm in which a hole elongated in a vertical direction is formed. The supporting member is retained by the bracket through a screw inserted into the elongated hole so as to permit the supporting member to move straight in the vertical direction along the elongated hole as well as to rotate in the vertical direction about the screw. 
   The elastic member is implemented by a coil spring disposed between the screw and the support arm. 
   The camera device further comprises a tilt plate disposed between the supporting member and the support arm. The tilt plate works to define a tilt angle of the supporting member relative to the bracket. 
   The bracket is made of an annular plate, thereby permitting the camera unit to move into a central opening of the bracket when subjected to a large-scaled impact, thus absorbing the impact completely. 
   The bracket is retained at a periphery thereof by at least one tension roller and a plurality of guide rollers, thereby allowing the bottom of the camera unit to be disposed close to a mount body, which permits the size of the camera device to be reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood more fully from the detailed description given hereinbelow and from the accompanying drawings of the preferred embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments but are for the purpose of explanation and understanding only. 
     In the drawings: 
       FIG. 1  is an exploded perspective view which shows a surveillance camera device according to the invention; 
       FIG. 2(   a ) is a perspective view which shows a camera unit; 
       FIG. 2(   b ) is a perspective view which shows a mount body; 
       FIG. 3  is an exploded view which shows the mount body of  FIG. 2(   b ); 
       FIG. 4  is an exploded view which shows the camera unit of  FIG. 2(   a ); 
       FIG. 5  is a perspective view which shows a conventional surveillance camera device; and 
       FIG. 6  is a perspective view which shows an internal structure of the camera device of  FIG. 5 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the drawings, particularly to  FIG. 1 , there is shown the angle fixed type of surveillance camera device consisting of a camera assembly  1  and a domed cover assembly  2 . In the following discussion, the terms “upper”, “lower”, “vertical”, and “horizontal” are used to refer to the orientation of the surveillance camera device disposed in the orientation shown in  FIG. 1 . 
   The camera assembly  1  consists essentially of a mount body  3  and a camera unit  4 . The mount body  3  has an upper flange  3   a  and a lower cylinder  3   b.  The camera unit  4  is installed on the mount body  3 . The flange  3   a  has an upper annular flat surface. An annular guide  3   c  is formed on a peripheral portion of the upper surface of the flange  3   a.  The domed cover assembly  2  is fitted on the periphery of the annular guide  3   c.  A ring-shaped upright wall  3   d  is installed as a reinforcement on the upper surface of the flange  3   a.  The domed cover assembly  2  consists of a dome  5  and a cover  6 . The dome  5  is made of a fully smoked polycarbonate resin and has a thickness of approximately 3.5 mm. The installation of the domed cover assembly  2  on the camera assembly  1  is achieved by inserting three screws  7  through mount holes  8  in the cover  6  into screw holes  9  in the guide  3   c  of the camera assembly  1 . 
   A main circuit substrate  11  is, as clearly shown in  FIG. 2(   b ), installed at sides thereof within the cylinder  3   b  of the mount body  3  through brackets  10 . A variety of adjustment switches  13  is joined to the main circuit substrate  11  through a harness  12 . A control cord  14  and a power cord  15  extend from the main circuit substrate  11  outside the cylinder  3   b  through cord bushings  16  and  17 . The control cord  14  is used to transmit a camera output to an external monitor. 
   Three hourglass-shaped guide rollers  18 ,  19 , and  20  are installed rotatably on the flange  3   a  at regular intervals inside the reinforcement wall  3   d . The guide rollers  18  and  19  are fitted on studs  21  and  22  projecting from the flange  3   a  and retained by screws  23  and  24 , respectively. The guide roller  20  works as a tension roller and installed rotatably by a screw  26  on an end of a lever  25  of a C-shape in cross section. The lever  25  is installed at the other end thereof on a stud  27  on the flange  3   a  rotatably by a screw  29  and urged by a torsion coil spring  28  inward of the flange  3 a in a radius direction. 
   The camera unit  4 , as clearly shown in  FIG. 2(   a ), includes an image capturing lens  31  installed on an upper end of a cylindrical casing  30 , a CCD sensor disposed on a focal point within the casing  30 , and a circuit substrate on which a camera control circuit is mounted. An adjustment ring  32  which is formed integrally with the casing  30  is fitted at a lower portion thereof in a hollow cylindrical rotary base  33  to be rotatable to adjust a yaw angle of the camera unit  4 . Harnesses  34  and  35  extend from the circuit substrate installed within the casing  30  and are joined at ends thereof to connectors  36  and  37  for electrical connections with the main circuit substrate  11  installed in the mount body  3 . Upright strips  33   a  and  33   b  are formed on diametrically opposed ends of the rotary base  33  and held by support arms  39  and  40  to be swingable. The support arms  39  and  40  extend vertically from a rotary bracket  38 . The rotary bracket  38  is supported at a periphery thereof by the guide rollers  18 ,  19 , and  20  of the mount base  3  to be rotatable horizontally or panable. 
   The rotary bracket  38  is, as clearly shown in  FIG. 4 , made of an annular plate. The upright arm  39  is formed integrally with the annular plate and extends vertically. The upright arm  40  is secured on the periphery of the annular plate through screws. The upright arms  39  and  40  have holes  41  and  42  elongated in a lengthwise direction thereof. An axis screw  43  consisting of an axis portion and a threaded portion is inserted into the elongated hole  41  from outside the upright arm  39  through an upper mount ring  44   a  of a torsion coil spring  44  and engaged in a screw hole  45  formed in the upright strip  33   a  of the rotary base  33 . A lower mount ring  44   b  of the torsion coil spring  44  is installed on the support arm  39  of the rotary bracket  38  through a small axis screw  46 . Specifically, the upper mount ring  44   a  and the lower mount ring  44   b  are hung on the axes of the screws  43  and  46  at a given interval away from each other, thus allowing the casing  30  to tilt to the rotary bracket  38 . The torsion coil spring  44  works to urge the axis screw  43  elastically into constant abutment on an upper end of the elongated hole  41 . An axis screw  47  is inserted into the elongated hole  42  from outside the support arm  40  through an upper mount ring  48   a  of a torsion coil spring  48  and engaged in a screw hole  50  formed in the upright strip  33   b  of the rotary base  33  through a hole  49   a  of a tilt plate  49 , so that the rotary base  33  or the casing  30  is supported by the rotary bracket  38  to be swingable vertically or tiltable. A lower mount ring  48   b  of the torsion coil spring  48  is installed rotatably on the support arm  40  of the rotary bracket  38  through a small axis screw  51 . The torsion coil spring  48  works to urge the axis screw  47  elastically into constant abutment on an upper end of the elongated hole  42 . The tilt plate  49  has formed therein a vertical groove  49   b  in which the hole  49   a  is formed and an arc-shaped horizontal guide hole  49 c formed in a lower portion of the vertical groove  49   b . The vertical groove  49   a  has a width substantially identical with that of the support arm  40 . The support arm  40  is engaged in the vertical groove  49   b  of the tilt plate  49  to hold the tilt plate  49  from rotating. A guide pin  52  installed on the upright strip  33 b of the rotary base  33  is inserted into the guide hole  49   c  to be swingable therewithin, thereby defining a tilt angular range within which the rotary base  33  or the casing  30  is tiltable relative to the rotary bracket  38 . 
   The installation of the surveillance camera device will be described below. 
   First, the connectors  36  and  37  of the camera unit  4  are joined to connectors installed on the main circuit substrate of the mount body  3 . Next, the guide roller  20  (i.e., the tension roller) is pressed outward through the lever  25  and kept as it is. The camera unit  4  is put in the mount body  3 . The periphery of the rotary bracket  38  of the camera unit  4  are placed in contact with the guide rollers  18  and  19 , after which the lever  25  is released to bring the guide roller  20  into contact with the periphery of the rotary bracket  38 , so that the rotary bracket  38  is pressed elastically by the torsion coil spring  28  of the guide roller  20 , thereby applying a brake to a horizontal rotation of the camera unit  4 . This permits the camera unit  4  to be adjusted in a pan angle and held at a desired horizontal angular position. The camera unit  4  is also rotatable vertically about the axis screws  43  and  47 , thereby permitting the camera unit  4  to be adjusted in a tilt angle and held at a desired vertical angular position. 
   Specifically, in the installation of the surveillance camera device on the ceiling or wall of a building, a surveillance orientation toward, for example, an entrance of the building is fixed by adjusting the pan angle and the tilt angle of the camera unit  4 . The pan angle is fixed by using a vis(es)  330  and a washer(s)  340 , as shown in  FIG. 2(   a ). The tilt angle is fixed by tightening the axis screws  43  and  47 . In a case where the surveillance camera unit is installed on a side wall of the building, the adjustment of the pan and tilt angles may cause an image captured by the camera unit  4  to be inclined. This inclination is corrected by turning the adjustment ring  32  of the casing  30  to adjust the yaw angle of the camera unit  4 . These adjustments are accomplished by an installation operator while watching the monitor. 
   The rotary base  33  working to support the camera unit  4  is, as described above, retained by the rotary bracket  38  using the screws  43  and  47  which are inserted into the holes  41  and  42  elongated vertically in the support arms  39  and  40  so as to allow the rotary base  33  to move straight in a vertical direction as well as to swing vertically to tilt the camera unit  4 . Thus, if the domed cover assembly  2  is beaten with, for example, a stick or bat, so that the impact is added to the camera unit  4 , it will cause the rotary base  33  to move vertically while compressing the torsion coil springs  44  and  48 , thereby absorbing the damaging impact on the camera unit  4 . 
   While the present invention has been disclosed in terms of the preferred embodiments in order to facilitate better understanding thereof, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, the invention should be understood to include all possible embodiments and modifications to the shown embodiments which can be embodied without departing from the principle of the invention as set forth in the appended claims. For instance, the surveillance camera device uses the rotary bracket  38  retaining the rotary base  33  carrying the camera unit  4  to be swingable vertically, but may alternatively use any other similar rotary mechanism. The camera unit  4  may alternatively be installed fixedly on the rotary base  33 . The rotary base  33  may alternatively be installed fixedly on the rotary bracket  38 . The torsion coil springs  44  and  48  used as elastic members working to absorb the impact on the camera unit  4  may be replaced with cushion members such as rubber. The cover  6  may alternatively be of any shape other than a dome.