You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     The present invention relates to a safety device and more particularly relates to a safety device for barring a passageway. 
     The use of a bar or barrier to block passage through a passageway finds use in many different situations. Generally, the bar or barrier is utilized to alert a person or a vehicle that there should not be any passage. While many different types of bars or barriers are utilized, one consideration in certain situations is that the barrier should not cause or incur damage if it is impacted. Otherwise, the cost of repairing or replacing the bar or barrier can be substantial, especially when it is a relatively frequent occurrence. 
     Barriers can be used in many different situations whenever it is decided to impede or stop traffic from flowing. This may be at an intersection where it is desirable to halt either pedestrian or vehicular traffic from crossing in a certain direction at a certain time. The barriers may also be used in situations where it is desirable to remind a person not to proceed unless certain steps are taken. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a breakaway bar or barrier which is sufficiently strong to perform its function as a barrier while having a breakaway arrangement whereby damage to the barrier is minimized when accidentally hit. 
     The barrier arrangement of the present invention may be utilized in any number of different situations such as set forth above. Thus, it can be used in conjunction with other safety devices such as with loading and unloading docks, intersections, and in any situation where it is appropriate to bar a passageway or the like. 
     The barrier components may be formed of any suitable material with the proviso that one or more portions thereof are of a magnetic metallic material. However, the other portions may be formed of suitable materials such as metals or plastics or the like. 
     The activation of the barrier may be accomplished by different means as will be discussed hereinbelow. It suffices to say that many different suitable activation/deactivation devices arrangements may be employed: these may be manual, mechanical or electrical, etc. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus generally described the invention, reference will be made to the accompanying drawings illustrating an embodiment thereof, in which: 
         FIG. 1  is a perspective view of a barrier according to one embodiment of the present invention; 
         FIG. 2  is a partially exploded view thereof; 
         FIG. 3  illustrates where the barrier may be utilized in conjunction with a loading/unloading situation; 
         FIG. 4  illustrates the trailer backed up to a door utilizing the barrier of the present invention; 
         FIG. 5  is an illustration of the barrier in an operative position; 
         FIG. 6  is an illustration of the barrier in an inoperative position; 
         FIG. 7  is a view of the trailer being removed from the loading dock; 
         FIG. 8  is a side view of the area wherein the arm is mounted to the pivot portion in a further embodiment of the present invention; 
         FIG. 9  is an exploded view of  FIG. 8 ; 
         FIG. 10  is a side elevational view of a further embodiment of the present invention when the barrier is in an operative position; 
         FIG. 11  is a side elevational view thereof in an inoperative position; and 
         FIGS. 12 to 14  are side elevational views of a further embodiment showing the barrier moving from an operative to an inoperative position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings in greater detail and by reference characters thereto, there is illustrated in  FIG. 1  a barrier which is in an operative position—i.e. to bar a passageway. The barrier is generally designated by reference numeral  10 . 
     The barrier is mounted on a post  12  adjacent a passageway which is to be barred. It will be understood that barrier  10  can also be mounted on any convenient structure adjacent the passageway. 
     Barrier  10  includes a mounting device generally designated by reference numeral  14  and which is designed to receive a bar  16 . Bar  16  conveniently can have a proximal end  18  with a magnetic portion  20  located thereat. Mounting device  14  includes a receptacle  22  for receiving magnetic portion  20  of proximal end  18 . 
     Mounting device  14  also includes a pivot portion  24  which can, in the illustrated embodiment, pivot through approximately 90° to move bar  16  from a horizontal position to a vertical position. Naturally, the degree of pivot can be either more or less depending on the particular situation. 
     In the illustrated embodiment, bar  16  has the magnetic portion  20  which is attracted to receptacle  22  which is of a suitable metallic material. It will be understood that this is merely one possible arrangement with others also capable of being utilized. Thus, in addition to magnetic portion  20 , receptacle  22  may also be magnetic, but of an opposite polarity. Still further, receptacle  22  could include the magnetic material while bar  16  is of a suitable metallic material. It suffices to say that such arrangements are within the skill of one knowledgeable in the art. Similarly, the particularly magnetic arrangement and the strength thereof may be varied according to the particular circumstances. One could utilize multiple magnets if desired. 
     As shown in  FIG. 3 , a trailer  28  is backing up to a loading dock  30 . When in position, a safety locking device  34  is utilized on the wheels of the trailer. 
       FIG. 5  illustrates a position wherein the barrier is operative to block passageway into the trailer. This can, for example, be the position when the trailer is not yet in position. 
       FIG. 6  illustrates the position wherein access is permitted to the trailer with the pivot portion  24  having moved to approximately 90° such that bar  16  is in a vertical position and passage is permitted. 
     If desired, one or more sensors  32  can be utilized to detect when arm  16  is in a certain position. 
     In the embodiment of  FIGS. 8 and 9 , a housing  136  is formed about the end of bar  116 . Housing  136  provides protection against pinching or the like when mounting bar  116  on pivot portion  124 . 
     This embodiment also utilizes an actuator  134  which comprises a moveable member which will detect when bar  116  is in position or has been rotated or knocked out of position. When bar  116  is mounted on pivot portion  124 , actuator  134  is forced by the end of bar  116  inwardly. However, as shown is  FIG. 9 , actuator  134  will move outwardly due to the magnetic field when bar  116  has been removed or knocked away. Actuator  134  may be connected, for example, to an audible or visual signal or other device to indicate whether bar  116  is in operative position. 
     The safety device of the present invention may be tied into other systems, both used for safety or other purposes. It will be understood that although the safety device of the present invention has been shown in one particular situation using a loading dock, it can be utilized anywhere where it is desired to restrict movement or indicate the passage is barred. The safety system may use proximity sensors, limit switches, and the like. 
     In the embodiment of  FIGS. 10 and 11 , a supplemental rod  15  is utilized in conjunction with barrier  16 . 
     Turning to the embodiment of  FIGS. 12 to 14 , there is illustrated a barrier  212  which is connected at one end to a pivot point  214 . One end of a cable  216  is connected to barrier  212  while the other end is connected to a moveable member  220 . A dampening device  218  such as spring, elastic material or rubber may be provided in cable  216 . A dampening means can also be mounted on barrier  212 . 
     A protrusion  222  is located at a lower point of a door  224 . As it moves upwardly, protrusion  222  engages moveable member  220  thus exerting a force on barrier  212  to cause the same to move upwardly. Moveable member  220  may assume many different forms and may be mounted in a slot or the like such that it will move in a desired path. 
     It will be understood that the above described embodiment is for purposes of illustration only and the changes and modifications may be made thereto without departing from the spirit and scope of the invention.

Summary:
A device for securing a passageway comprising a barrier on a mounting member, the barrier being retained by magnetic attraction between the mounting member and the barrier, the mounting member being pivotably moveable between operative and inoperative positions.