Abstract:
A bumper device for an Automated Guided Vehicle (AGV) includes a bumper supporting member combined to a vehicle body of the AGV, and a bumper supported on the bumper supporting member. The bumper device also includes a movement supporting device installed at the bumper supporting member and to movably support the bumper, and a movement sensor to sense a movement of the bumper. Thus, the bumper device promptly senses and effectively absorbs an impact from multiple directions.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a bumper device for an automated guided vehicle (AGV). 
     2. Description of the Related Art 
     An AGV is an apparatus for a factory automation system, for conveying goods, articles, etc. without manipulation by hand in a factory. 
     The AGV automatically travels along a predetermined path by a controller (not shown) installed therein, and thus the AGV is equipped with a bumper device protecting a vehicle body in preparation for a possible impact on running. 
     A conventional bumper device  201  for an AGV  205 , as shown in FIG. 9, comprises a bumper member  280  installed at a circumference of a vehicle body  207 , and an impact sensor  290  installed inside the bumper member  280 . 
     The bumper member  280  is made of an elastic material such as rubber, plastics, etc. in order to absorb a shock generated when the AGV  205  impacts on other objects. Further, the impact sensor  290  is of a shape corresponding to the bumper member  280  so as to sense an impact given on the bumper member  280 . The impact sensor  290  is installed inside the bumper member  280  by way of an insert molding. Further, the impact sensor  290  is electrically connected to the controller of the AGV  205 . 
     With this configuration, in the conventional bumper device  201 , if the AGV  205  impacts on other objects, the bumper member  280  absorbs the impact, and the impact sensor  290  senses the impact transmitted from the bumper member  280  and transmits it to the controller (not shown) of the AGV  205 . Then, the controller stops the AGV  205 . 
     However, in the conventional bumper device, because the impact sensor is insert-molded in the bumper member, it is impossible to sense an impact generated beyond a sensing area. That is, there is a problem that the sensing area is limited with respect to regions and direction in which impacts are generated. 
     In addition, because the impact sensor is insert-molded inside the bumper member, a distance between an impact position and the impact sensor may be not uniform due to a molding tolerance, a dimensional tolerance, or etc., during a manufacturing process thereof. Thus, a sensitivity of the impact sensor may be different according to an impact region of the bumper device. 
     Moreover, because the bumper member is fixed on the AGV and absorbs an impact with elasticity of the bumper member itself, the bumper device has limitations in an absorbing capability. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made keeping in mind the above-described shortcoming and user&#39;s need, and an object of the present invention is to provide a bumper device for an AGV, which can promptly sense and effectively absorb an impact given from every region and every direction. 
     This and other objects of the present invention may be accomplished by the provision of a bumper device for an AGV comprising a bumper which absorbs a shock generated in a backward direction of a bumper supporting member combined with a vehicle body of the AGV. The bumper is supported on the bumper supporting member. The bumper device includes a movement supporting means installed at the bumper supporting member to movably support the bumper, and a movement sensor to sense a movement of the bumper. 
     Preferably, the movement supporting means includes a backward and forward shock absorber. 
     Effectively, the backward and forward shock absorber is comprised of a guide provided on the bumper supporting member along a backward and forward direction; a supporting slider coupled to the guide so as to slide backward and forward, and supporting the bumper; a backward and forward shock absorbent member installed at the bumper supporting member at the rear of the supporting slider and elastically diminishing a backward movement of the supporting slider. 
     Preferably, the backward and forward shock absorbent member is comprised of a spring supporter installed at the rear of the guiding slider, and a backward and forward shock absorbent spring held between the spring supporter and the supporting slider. 
     Effectively, at the spring supporter is installed a spring holding shaft supporting the backward and forward shock absorbent spring; and on the supporting slider is formed a shaft hole through which the spring holding shaft passes. 
     Preferably, the movement supporting means includes a multi-directional shock absorber installed in front of the supporting slider and absorbing multi-directional shock of the bumper. 
     Effectively, the multi-directional shock absorber is comprised of a slider connector combined to the supporting slider; a bumper connector combined to the bumper; and a universal joint movably combining the slider connector with the bumper. 
     Preferably, one end of the bumper connector directly toward the bumper is combined with a rotary shaft perpendicular to a sliding direction of the supporting slider; and on the bumper is provided a rotary shaft accommodating part rotatably combined to the rotary shaft. 
     Effectively, the bumper is comprised of a bumper plate perpendicular to the guide, and an elastic absorbent member combined on the front of the bumper plate; and the rotary shaft accommodating part is provided on the rear of the bumper plate. 
     Preferably, the bumper device further comprises a multi-directional shock absorbent spring surrounding the multi-directional shock absorber between the supporting slider and the bumper and absorbing the shock of impact on the bumper. 
     Effectively, the movement sensor includes a sensor plate combined to the bumper and having a sensing hole thereon; a light element emitting light passing through the sensing hole; and a light receiving element sensing the light passed through the sensing hole from the light element. 
     Preferably, the bumper device further comprises a droop preventive unit having one end combined to the bumper supporting member and the other end contacting with a rear lower part of the bumper, in order to prevent the bumper from drooping. 
     Effectively, the droop preventive unit is comprised of a hollow plunger-accommodating member combined to the bumper supporting member; a plunger spring accommodated in the plunger-accommodating member; and a plunger accommodated in the plunger-accommodating member and contacting with a rear lower part of the bumper by elasticity of the plunger spring. 
     Preferably, the movement supporting means is provided in pairs at opposite sides of the bumper plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a bumper device for an AGV according to a first embodiment of the present invention; 
     FIGS. 2 and 3 are a top plan views showing actions of the bumper device for the AGV of FIG. 1; 
     FIGS. 4 and 5 are side views showing actions of the bumper device for the AGV of FIG. 1; 
     FIG. 6 is a section view showing a part taken along line VI—VI of FIG. 2; 
     FIG. 7 is a perspective view showing the AGV equipped with the bumper device of FIG. 1; 
     FIG. 8 is a top plan view of a bumper device for an AGV according to a second embodiment of the present invention; and 
     FIG. 9 is a schematic perspective view of a conventional bumper device for an AGV. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings. 
     FIG. 1 is a perspective view of a bumper device for an AGV according to a first embodiment of the present invention. As shown therein, the bumper device  1  for the AGV comprises a bumper supporting member  70  combined to a vehicle body  7  of the AGV  5  (see FIG.  7 ), a bumper  80  movably combined to the bumper supporting member  70 , a movement sensor  90  (see FIG. 4) sensing a movement of the bumper  80 , and at least one movable supporting means  10  installed on the bumper supporting member  70  and movably supporting the bumper  80 . 
     The bumper supporting member  70  includes a combining plate  71  combined to a bottom part of the vehicle body  7  of the AGV  5 , and a guiding plate  73  provided on the combining plate  71  and forming a mounting plate on which the movable supporting means  10  are installed. The combining plate  71  is of a rectangular shape with a predetermined area. The combining plate  71  is combined to the bottom part of the vehicle body  7  by means of bolts, welding, or etc. Further, the guiding plate  73  has an enough area to install the movable supporting means  10  thereon. Here, it is desirable that the combining plate  71  and the guiding plate  73  are manufactured separately and then combined to each other. 
     The bumper  80  includes a bumper plate  81  provided in parallel with a side of the vehicle body  7  of the AGV  5 , and an elastic absorbent member  83  combined to the front of the bumper plate  81 . 
     The bumper plate  81  is approximately of a rectangular shape having a predetermined width and a length corresponding to the length of the side of the vehicle body. The absorbent member  83  is made of an elastic material such as rubber, plastics, etc. in order to absorb a shock generated when the AGV  5  impacts on other objects. In this case, it is desirable that the absorbent member  83  should have an enough elasticity to absorb the shock and transmit it to the bumper plate  81 . 
     The movement sensor  90 , as shown in FIGS. 4 and 5, includes a sensor plate  91  having one end combined to the bumper plate  81  and the other end backwardly extended from the bumper plate  81 , and an optical sensor  95  installed at the bumper supporting member  70  and sensing the movement of the sensor plate  91 . At a rear part of the sensor plate  91  is formed a sensing hole  93 . The optical sensor  95  is comprised of a light element  97  emitting light passing through the sensing hole  93  and a light receiving element  99  sensing the light passed through the sensing hole  93 , the sensor plate  91  being positioned therebetween. The optical sensor  95  is electrically connected to a controller (not shown) controlling an operation of the AGV  5 . Thus, where the sensor plate  91 , together with the sensing hole  93 , moves depending on an impact of the bumper  80 , light from the light element  97  is not transmitted to the light receiving element  99 , and which is transmitted it to the controller (not shown) of the AGV  5 . 
     The movable supporting means  10  includes a backward and forward directional shocks absorber  11  installed on the bumper supporting member  70  and absorbing backward and forward directional shocks from the bumper  80 , and a multi-directional shock absorber  13  installed between the backward and forward shock absorber  11  and the bumper  80  and absorbing multi-directional shocks from the bumper  80 . 
     The backward and forward shock absorber  11  is comprised of a guide  20  provided on the guiding plate  73  along a backward and forward direction, a supporting slider  30  sliding backward and forward along the guide  20 , a backward and forward shock absorbent member  40  installed at the rear part of the supporting slider  30  and elastically diminishing a backward movement of the supporting slider  30 . 
     The guide  20  may be manufactured separately and then combined to the guiding plate  73 , or may be manufactured in one united body. Opposite end parts of the guide  20  are provided with stoppers  21  preventing the supporting slider  30  from separating from the guide  20 . 
     The supporting slider  30  is comprised of a sliding part  31  sliding along the guide  20 , and a supporting part  35  extended from a part of the sliding part  31 , perpendicular to the guide  20 . 
     On a surface of the sliding part  31 , which faces the guide  20 , is formed a guiding groove  33  for engaging with the guide  20 . It is desirable that the guide  20  and the guiding groove  33  are combined to each other in a dovetail manner so as to prevent the sliding part  31  from coming off the guide  20 . 
     On an area of the supporting part  35 , which is adjacent to the guide  20  is provided a shaft hole  36  through which a spring holding shaft  43  of the backward and forward shock absorbent member  40  passes. Further, on a free end of the supporting part  35  is provided a movable unit hole  37  (see FIG. 6) to which the multi-directional shock absorber  13  is combined. The movable unit hole  37  is formed with a female screw  39  on the inside thereof, and is covered by a cover plate  38  at the rear part of the supporting part  35 . 
     The backward and forward shock absorbent member  40  is comprised of a spring supporter  41  installed on the guiding plate  73 , and a backward and forward directional shock absorbent spring  45  held between the spring supporter  41  and the supporting part  35  of the supporting slider  30 . 
     The spring supporter  41  is standing on the guiding plate  73 . The front of the spring supporter  41  is combined with the spring holding shaft  43  (see FIGS. 2 and 4) whose free end passes through the shaft hole  36  provided on the supporting part  35  of the supporting slider  30 . Further, the backward and forward shock absorbent spring  45  surrounds the spring holding shaft  43 . 
     The multi-directional shock absorber  13  is comprised of a movement supporting unit  50  supporting an up and down movement and a lateral movement of the bumper  80 , a rotary supporting unit  60  supporting a rotational movement of the bumper  80  in forward and backward directions, and a multi-directional shock absorbent spring  15  diminishing the movement of the bumper  80 . 
     The movement supporting unit  50  is, as shown in FIG. 6, comprised of a slider connector  51  combined to the movable unit hole  37  of the supporting slider  30 , a bumper connector  55  combined to the bumper  80 , and a universal joint  57  provided between the slider connector  51  and the bumper connector  55  and movably combining the slider connector  51  with the bumper connector  55 . 
     On a rear part of the slider connector  51  is formed a male screw  53  corresponding to the female screw  39  formed on the movable unit hole  37 . The universal joint  57  is comprised of a bail accommodating part  58  formed at a free end of the  51  bumper connector  55 , and a ball  59  integrally formed at the rear part of the slider connector  51  and being movably accommodated in the ball accommodating part  58 . Here, the positions of the ball accommodating part  58  and the ball  59  may be changed with respect to each other. Further, the ball accommodating part  58  and the ball  59  may be manufactured separately from the bumper connector  55  and the slider connector  51 , respectively, and then combined with each connector. On the free end of the bumper connector  55  is formed a male screw  56 . 
     The rotary supporting unit  60  is, as shown in FIG. 6, comprised of a rotary shaft  61  combined to the free end of the bumper connector  55 , a rotary shaft accommodating part  67  provided at the rear part of the bumper plate  81  and rotatably combined with the rotary shaft  61 . 
     On a backward center of the rotary shaft  61  is formed a female screw  63  corresponding to the male screw  56  of the bumper connector  55 . On up and down parts of the rotary shaft  61  are provided projections  65  for combining with the rotary shaft accommodating part  67 . 
     The rotary shaft accommodating parts  67  are provided at both sides on the rear of the bumper plate  81 . Each rotary shaft accommodating part  67  has a pair of combining plates  68  parallel to each other and protruded from the rear up and down parts of the bumper plate  81 . On the center of each combining plate  68  is provided a rotary shaft hole  69  through which the projection  65  of the rotary shaft  61  is rotatably inserted. 
     The multi-directional shock absorbent spring  15  is installed between the supporting part  35  of the supporting slider  30  and the rotary shaft accommodating part  67  of the bumper  80  so as to surround the movement supporting unit  50 . 
     In addition, the bumper device  1  for the AGV  5  according to the present invention further comprises a droop preventive unit  75  for preventing the bumper  80  from drooping. As shown in FIGS. 4 and 5, the droop preventive unit  75  includes a hollow plunger-accommodating member  77  combined to the bumper supporting member  70 , a plunger spring  78  accommodated in the plunger-accommodating member  77 , and a plunger  79  accommodated in the plunger-accommodating member  77  and contacting with the rear of the bumper  80  by elasticity of the plunger spring  78 . The rear end of the plunger-accommodating member  77  is combined to a supporter  76  provided on the bumper supporting member  70 . The droop preventive unit  75  allows the plunger  79  to elastically push the lower part of the bumper  80 , thereby preventing the bumper  80  from drooping due to a self-weight thereof. 
     With this configuration, the bumper device  1  for the AGV  5  according to the present invention is, as shown in FIG. 7, combined with the lower part of the vehicle body  7  of the AGV  5 , and absorbs and senses the shock of impact, thereby stopping the AGV  5 . Herein, the bumper device  1  may be installed at on at least one side of the vehicle body  7 . 
     Hereinbelow, an operation of the bumper device  1  for the AGV will be described. 
     While the AGV  5  is traveling, if the bumper  80  impacts other objects, firstly, the shock of impact is absorbed in the elastic absorbent member  83  of the bumper  80  and makes the bumper plate  81  move. At this time, as shown in FIG. 3, if the impact region is the left part or the right part of the bumper  80 , the bumper plate  81  turns around the rotary shaft  61  of the rotary supporting unit  60  and moves back at one universal joint  57  of the movement supporting unit  50 . As shown in FIG. 5, if the impact region is the upper part or the lower part of the bumper  80 , the bumper plate  81  moves from up to down at the universal joints  57  of the movement supporting unit  50 . 
     If the bumper plate  81  moves, secondly, the shock of impact is absorbed in the multi-directional shock absorbent spring  15 . Thereafter, the shock of impact, which is not absorbed by the absorbent member  83  and the multi-directional shock absorbent spring  15  is absorbed by making the supporting slider  30  move back along the guide  20 , and therefore the backward and forward shock absorbent spring  45  completely absorbs the shock of impact. 
     Further, if the bumper plate  81  moves depending on an impact on the bumper  80 , the movement sensor  90  senses the movement of the bumper plate  81  and transmits it to the controller (not shown) of the AGV  5 , while the shock of impact is absorbed in the absorbent member  83 , the backward and forward shock absorber  11 , and the multi-directional shock absorber  13 . 
     That is, if the bumper plate  81  moves, the sensor plate  91  combined to the bumper plate  81  moves, and therefore the sensing hole  93  moves. Then, the light being transmitted from the light element  97  to the light receiving element  99  is swerved from the sensing hole  93  due to the movement of the sensor plate  91 . That is, the light from the light element  97  cannot pass through the sensing hole  93 , and therefore does not reach the light receiving element  99 . Then, the movement sensor  90  transmits an impact signal to the controller (not shown) of the AGV  5 , and the controller stops the AGV  5 . 
     FIG. 8 is a top plan view of a bumper device for an AGV  5  according to a second embodiment of the present invention. As shown therein, unlike the bumper device  1  of FIG. 1, the bumper device  101  for the AGV  5  according to the second embodiment comprises a single multi-directional shock absorber  113  as a movable supporting means. 
     The multi-directional shock absorber  113  is comprised of a movement supporting unit  150  combined with a bumper supporting member  170  and supporting an up and down movement and a lateral movement of the bumper  180 , a rotary supporting unit  160  supporting a rotational movement of the bumper  180  in forward and backward directions, and a multi-directional shock absorbent spring  115  diminishing a movement of the bumper  180 . 
     The movement supporting unit  150 , the rotary supporting unit  160 , the multi-directional shock absorbent spring  115 , and a movement sensor  190  are the same as those of the bumper device  1  of FIG. 1 according to the first embodiment. Therefore, the descriptions for the first embodiment will be incorporated herein. 
     With this configuration, in the bumper device  101  according to the second embodiment, if the bumper  180  impacts on other objects while the AGV  5  is traveling, firstly, the shock of impact is absorbed in an elastic absorbent member  183  of the bumper  180  and makes the bumper plate  181  move along the impact direction. That is, if the bumper  180  impacts on other objects, the bumper plate  181  moves along a direction according to the movement supporting unit  150  or the rotary supporting unit  160 . Then, if the bumper plate  181  moves, secondly, the shock of impact is absorbed in the multi-directional shock absorbent spring  115 . 
     Further, if the bumper plate  181  moves according to impact of the bumper  180 , the movement sensor  190  senses the movement of the bumper plate  181  and transmits it to the controller (not shown) of the AGV  5 , while the shock of impact is absorbed in the absorbent member  183  and the multi-directional shock absorber  113 . Then, the movement sensor  190  transmits an impact signal to the controller so as to stop the AGV  5 . Because a sensing operation of the movement sensor  190  is the same as that of the bumper device  1  of FIG. 1, detailed descriptions thereof will be omitted. 
     As described above, a bumper absorbing a shock is movably installed and a movement sensor sensing a movement of the bumper is provided, so that the shock of impact in every region and every direction on a bumper can be promptly sensed. 
     Moreover, the sensitivity thereof is improved because the movement sensor senses the movement of a bumper plate, and an absorbing function of a bumper device is improved because the shock is absorbed by the movement of the bumper. 
     As described above, the present invention provides a bumper device for an AGV, which can promptly sense and effectively absorb a shock of impact in every area and every direction. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.